Metal organic frameworks á heterogeneous catalysts for the synthesis ò quinazolinones and pyridines

VIETNAM NATIONAL UNIVERSITY - HO CHI MINH CITY
UNIVERSITY OF TECHNOLOGY

NGUYEN THI NGOC TRAN

METAL-ORGANIC FRAMEWORKS AS
HETEROGENEOUS CATALYSTS
FOR THE SYNTHESIS OF
QUINAZOLINONES AND PYRIDINES

Major: Chemical engineering
Major ID: 60 52 03 01

M. ENG. THESIS

HO CHI MINH CITY, JAN 2019


CƠNG TRÌNH ĐƯỢC HỒN THÀNH TẠI
TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐHQG – HCM
Cán bộ hướng dẫn khoa học 1 : GS.TS. Phan Thanh Sơn Nam
(Ghi rõ họ, tên, học hàm, học vị và chữ ký)
Cán bộ hướng dẫn khoa học 2 : ..................................................................
(Ghi rõ họ, tên, học hàm, học vị và chữ ký)
Cán bộ chấm nhận xét 1 : PGS.TS. Nguyễn Thị Phương Phong
(Ghi rõ họ, tên, học hàm, học vị và chữ ký)
Cán bộ chấm nhận xét 2 : TS. Lê Vũ Hà
(Ghi rõ họ, tên, học hàm, học vị và chữ ký)
Luận văn thạc sĩ được bảo vệ tại Trường Đại học Bách Khoa, ĐHQG TP. HCM
ngày 12 tháng 01 năm 2019
Thành phần Hội đồng đánh giá luận văn thạc sĩ gồm:

(Ghi rõ họ, tên, học hàm, học vị của Hội đồng chấm bảo vệ luận văn thạc sĩ)
1. PGS.TS. Phạm Thành Quân
2. PGS.TS. Nguyễn Thị Phương Phong
3. TS. Lê Vũ Hà
4. PGS.TS. Nguyễn Đình Thành
5. TS. Nguyễn Thanh Tùng
Xác nhận của Chủ tịch Hội đồng đánh giá luận văn và Trưởng Khoa quản lý
chuyên ngành sau khi luận văn đã được sửa chữa (nếu có).
CHỦ TỊCH HỘI ĐỒNG

TRƯỞNG KHOA KTHH


ĐẠI HỌC QUỐC GIA TP.HCM
TRƯỜNG ĐẠI HỌC BÁCH KHOA

CỘNG HÒA XÃ HỘI CHỦ NGHĨA VIỆT NAM
Độc lập - Tự do - Hạnh phúc

NHIỆM VỤ LUẬN VĂN THẠC SĨ
Họ tên học viên: NGUYỄN THỊ NGỌC TRÂN..................... MSHV:1770010 ..............
Ngày, tháng, năm sinh: 19/11/1994 ........................................... Nơi sinh: Long An ..........
Chuyên ngành: Kỹ thuật hóa học .............................................. Mã số : 60520301...........
I. TÊN ĐỀ TÀI:
Metal-organic frameworks as heterogeneous catalysts for the synthesis of
quinazolinones and pyridines.
II. NHIỆM VỤ VÀ NỘI DUNG:
- Sử dụng xúc tác dị thể Cu-MOF-74 cho phản ứng tổng hợp quinazolinones.
- Sử dụng xúc tác dị thể MOF VNU-20 cho phản ứng tổng hợp pyridines.
III. NGÀY GIAO NHIỆM VỤ : 13/08/2018

IV. NGÀY HOÀN THÀNH NHIỆM VỤ: 12/01/2019
V. CÁN BỘ HƯỚNG DẪN
Cán bộ hướng dẫn : GS.TS. PHAN THANH SƠN NAM

Tp. HCM, ngày 22 tháng 01 năm 2019.
CÁN BỘ HƯỚNG DẪN

CHỦ NHIỆM BỘ MÔN ĐÀO TẠO

(Họ tên và chữ ký)

(Họ tên và chữ ký)

TRƯỞNG KHOA KỸ THUẬT HÓA HỌC
(Họ tên và chữ ký)


ACKNOWLEDGEMENTS
First and foremost, I would like to thank Prof. Phan Thanh Son Nam for the
financial support for this project and also gave me guidance on this thesis with his
comprehensive knowledge. Working with them is an honor and a valuable experience
for me.
Especially, my profound gratitude is expanded to all the teaching staffs of the
Organic Chemistry Department, for the valuable information provided by them in their
respective fields. Their unconditional love and support have always accompanied with
every achievement in my life.
In addition, I would like to thank my talented and loyal friends: Mr. Phuc. H. Pham
and Mr. Vu. H. H. Nguyen, Miss Tram. T. Van, Miss Que. T. D. Nguyen for their
encouragement and support during my hardest time. Their advices made me always
have the positive attitude and helped me complete this thesis.

Finally, I would like to express my sincere gratitude to my parents. Their love,
encouragement and continuous support have always been with me in every
achievement I get in my life.

Ho Chi Minh City, December, 2018
Nguyen Thi Ngoc Tran


ABSTRACT
Generally, this thesis focuses on applying metal-organic frameworks as efficient
solid catalysts for diverse transformations. According to that, two MOFs were
successfully synthesized by solvothermal method. A crystalline porous copper-based
metal-organic framework named Cu-MOF-74 was generated from Cu(NO3)2.3H2O and
2.5-dihydroxyterephthalic acid while a mixed-linker iron-based MOF named VNU-20
[Fe3(BTC)(NDC)2·6.65H2O] was prepared from 1,3,5-benzenetricarboxylic acid, 2,6naphthalenedicarboxylic acid and FeCl2. Physical characterizations
catalysts were obtained by several analysis
diffraction (PXRD),

of the solid

techniques including powder

X-ray

transmission electron microscopy (TEM), thermogravimetric

analysis (TGA), Fourier transform infrared (FT-IR), and

atomic absorption

spectroscopy (AAS). The results indicated that the desired structures of the MOFs
were obtained.
For the first time, the Cu-MOF-74 was used as a heterogeneous catalyst for the
reaction between 2-phenylindole and phenethylamine to afford the 3-phenethyl-2phenylquinazolin-4(3H)-one in excellent conversion. Indeed, the reaction offered
many advantages as compared to previous works including low catalyst loading, and
milder conditions. VNU-20 was found to be more active for the cyclization of
ketoxime carboxylates and dibenzyl ether than several conventional molecular and
MOF-based heterogeneous catalysts, which has not mentioned in previous reports yet.
These MOFs not only exhibited high catalytic possibilities but also could be reused for
several times without any considerable decline in efficiency. Due to the benefits of
quinazolinone and pyridine derivatives in pharmaceutical and chemical industry, the
scope of the reactions was expanded by varying many substrates to obtain a broad
range of desired products.


CONTENTS
ACKNOWLEDGEMENTS ........................................................................................ iv
ABSTRACT ...................................................................................................................v
CONTENTS ................................................................................................................. vi
LIST OF FIGURES ..................................................................................................... ix
LIST OF SCHEME ..................................................................................................... xi
LIST OF TABLES ..................................................................................................... xiv
LIST OF ABBREVIATION .......................................................................................xv
CHAPTER 1: LITERATURE REVIEW ....................................................................1
1.1

METAL-ORGANIC FRAMEWORKS (MOFS) ......................................................1

1.1.1 General introduction ........................................................................................1
1.1.2 General methods for the synthesis of MOFs ...................................................3

1.1.3 Application of MOFs .......................................................................................4
1.2

INTRODUCTION TO CU-MOF-74 AS AN EFFICIENT HETEROGENEOUS

CATALYST ....................................................................................................................9

1.3

INTRODUCTION TO IRON-BASED METAL-ORGANIC FRAMEWORKS AND IRON-

BASED

MOF VNU-20 [FE3(BTC)(NDC)2.6.65H2O] AS A HETEROGENEOUS

CATALYST ..................................................................................................................19

1.4

THE QUINAZOLINONES SYNTHESIS OF 2-ARYLINDOLES WITH AMINES

UTILIZING CU-MOF-74 AS AN EFFICIENT HETEROGENEOUS CATALYST ..............25

1.5

THE CYCLIZATION REACTIONS OF KETOXIME ACETATES AND DIBENZYL

ETHER TO PRODUCE PYRIDINES UTILIZING

MOF VNU-20 AS A HETEROGENEOUS

CATALYST ..................................................................................................................35

1.6

AIMS AND OBJECTIVES ...................................................................................49

CHAPTER 2: EXPERIMENTAL SECTION ..........................................................51
2.1.

MATERIALS AND INSTRUMENTATION ............................................................51

2.2.

SYNTHESIS OF THE METAL-ORGANIC FRAMWORKS (MOFS) ......................53

2.2.1 Synthesis of Cu-MOF-74..............................................................................53
2.2.2 Synthesis of VNU-20....................................................................................54


2.3.

CATALYTIC TESTS ...........................................................................................54

2.3.1 Catalytic studies in the expansion reaction to produce 2-arylquinazolinones
54
2.3.2 Catalytic studies in the cyclization reaction of ketoxime acetates and
dibenzyl ether to synthesize 2,4,6-triphenyl pyridine .............................................55
CHAPTER 3. RESULT AND DISCUSSION ...........................................................58
3.1

THE CU-MOF-74-CATALYZED BAEYER-VILLIGER OXIDATION EXPANSION

REACTION TO SYNTHESIZE 2-ARYLQUINAZOLINONES ............................................58

3.1.1 Synthesis and characterization of Cu-MOF-74 ............................................58
3.1.2 Catalytic studies in the synthesis of 2-arylquinazolinones ...........................63
3.1.2.1 Effect of temperature on the reaction ....................................................64
3.1.2.2 Effect of solvent on the reaction ............................................................66
3.1.2.3 Effect of reactant molar ratio on the reaction yield ...............................67
3.1.2.4 Effect of catalyst quantity on the reaction yield ....................................68
3.1.2.5 Effect of different catalysts on the reaction yield ..................................69
3.1.2.6 Leaching test ..........................................................................................71
3.1.2.7 Catalyst reusability ................................................................................72
3.1.2.8 Effect of different substituents on the reaction ......................................75
3.1.2.9 Conclusion .............................................................................................77
3.2

THE MIXED-LINKER MOF VNU-20-CATALYZED CYCLIZATION REACTIONS

OF KETOXIME ACETATES AND DIBENZYL ETHER TO PRODUCE SYMMETRICAL
PYRIDINES ..................................................................................................................77

3.2.1 Synthesis and characterization of VNU-20 ..................................................77
3.2.2 Catalytic studies in the synthesis of symmetrical pyridines .........................78
3.2.2.1 Effect of temperature on the reaction ....................................................79
3.2.2.2 Effect of solvent on the reaction ............................................................80
3.2.2.3 Effect of ratio reactants on the reaction .................................................82
3.2.2.4 Effect of catalyst amount on the reaction ..............................................83
3.2.2.5 Effect of time on the reaction ................................................................84

3.2.2.6 Effect of oxidant on the reaction ...........................................................85
3.2.2.7 Effect of oxidant amount on the reaction ..............................................86
3.2.2.8 Effect of antioxidant on the reaction .....................................................87
3.2.2.9 Leaching test ..........................................................................................89


3.2.2.10 Pyridine test ...........................................................................................90
3.2.2.11 Catalyst reusability ................................................................................91
3.2.2.12 Effect of different catalysts on the reaction ...........................................93
3.2.2.13 Effect of different atmospheres on the reaction .....................................96
3.2.2.14 Effect of different substituents on the reaction ......................................97
3.2.2.15 Plausible mechanism............................................................................101
3.2.2.16 Conclusion ...........................................................................................105
CHAPTER 4. CONCLUSION .................................................................................107
REFERENCES ..........................................................................................................109
APPENDIX A: CALIBRATION CURVE ..............................................................118
APPENDIX B: GC YIELD .......................................................................................121
APPENDIX C: CHARACTERIZATION DATA ...................................................129


LIST OF FIGURES
Figure 1. 1: Progress in the synthesis of ultrahigh porosity MOFs. The values in
parentheses represent the pore volume (m3/ g) of these materials [4].............................1
Figure 1. 2: Growth of the Cambridge Structural Database (CSD) and MOF entries
since 1972 [5]. The inset shows the MOF self-assembly process from building blocks:
metals (red spheres) and organic ligands (blue struts). ...................................................2
Figure 1. 3: Overview of synthesis methods, possible reaction temperatures, and final
reaction products in MOFs synthesis [10]. ......................................................................3
Figure 1. 4: Interaction of a substrate molecule, S, with a metal site, M, through (a)
expansion of the coordination sphere around the metal ion; or (b) (reversible)

displacement of one of the ligands [22]. .........................................................................6
Figure 1. 5: Color changes during the dehydration of Cu3(BTC)2(H2O)3.xH2O to give
Cu3(BTC)2, and subsequent readsorption of the aldehyde to give
Cu3(BTC)2(C6H5CHO)x [24]. ..........................................................................................7
Figure 1. 6: General structure and selected examples of ligands containing
coordinative and reactive functional groups [22]. ...........................................................8
Figure 1. 7: Crystal structure of a MOF-74 (left) and metal oxide chains connected by
organic linkers (right). O, red; C, black, H, white; metal, blue [33]. ............................10
Figure 1. 8: Solvothermal synthesis of MOF structures [35]. ......................................11
Figure 1. 9: CO2 adsorption–desorption isotherms at different temperatures of
Cu2(dhtp) [34]. ...............................................................................................................13
Figure 1. 10: Total yields of the products that result from the oxidation of
cyclohexene in the presence of M–MOF-74 and without catalyst (blank) with TBHP.
.......................................................................................................................................14
Figure 1. 11: Comparison of different types of acid catalysts for the acylation of
anisole [36]. ...................................................................................................................15
Figure 1. 12: Pores in the M2dobdc MOF (brown = carbon; orange = metal; red =
oxygen).[31] ..................................................................................................................16
Figure 1. 13: Three types of Quinazolinones. ..............................................................25
Figure 1. 14: The crystal structure of VNU-20 (b) are linked horizontally and
vertically by BTC3− and NDC2−, respectively (a, e and f) to form the orange-red
crystals (d) with structure highlighted with a rectangular window of 6.0 × 8.7 Å2 (c).
Atom colors: Fe, blue and orange polyhedra; C, black; O, red. All H atoms are omitted
for clarity [67]. ...............................................................................................................20
Figure 1. 15: Pyridine core and several pyridine derivatives [87, 88]. ........................36
Figure 3. 1: PXRD patterns of the simulated (a) and synthesized (b) Cu-MOF-74 58
Figure 3. 2: FT-IR spectra of terephthalic acid and the Cu-MOF-74 ..........................60
Figure 3. 3: TGA curve of the Cu-MOF-74 .................................................................61
Figure 3. 4: SEM micrograph of the Cu-MOF-74........................................................61
Figure 3. 5: TEM micrograph of Cu-MOF-74 at 500nm and 100nm ..........................62

Figure 3. 6: Pore size distribution of Cu-MOF-74 .......................................................62
Figure 3. 7: Isotherm linear plot of Cu-MOF-74..........................................................63
Figure 3. 8: Effect of temperature on the reaction yield. .............................................65
Figure 3. 9: Effect of solvent on the reaction yield ......................................................66
Figure 3. 10: Effect of reactant molar ratio on the reaction yield ................................68
Figure 3. 11: Effect of catalyst quantity on the reaction yield .....................................69
Figure 3. 12: Effect of homogeneous catalysts on the reaction yield ..........................70
Figure 3. 13: Effect of heterogeneous catalysts on the reaction yield..........................71
Figure 3. 14: Leaching test indicated no contribution from homogeneous catalysis of
active species leaching into reaction solution. ..............................................................71
Figure 3. 15: Catalyst recycling studies .......................................................................72
Figure 3. 16: PXRD patterns of the simulated (a) and synthesized (b) Cu-MOF-74...74
Figure 3. 17: FT-IR spectra of the Cu-MOF-74 ...........................................................74
Figure 3. 18: Effect of different temperatures on the reaction yield ............................79
Figure 3. 19: Effect of solvent to the reaction. .............................................................80
Figure 3. 20: Effect of molar ratio of dibenzyl ether /(E)-acetophenone O-acetyl
oxime acetate on the reaction yield ...............................................................................82
Figure 3. 21: Effect of catalyst amount on the reaction yield. .....................................83
Figure 3. 22: Effect of time on the reaction. ................................................................84
Figure 3. 23: Effect of oxidant on the reaction.............................................................85
Figure 3. 24: Effect of oxidant amount on the reaction. ..............................................86
Figure 3. 25: Effect of antioxidant on the reaction. .....................................................88
Figure 3. 26: Leaching test indicated no contribution from homogeneous catalysis of
active species leaching into reaction solution. ..............................................................89
Figure 3. 27: Pyridine test ............................................................................................90
Figure 3. 28: Catalyst reusing studies. .........................................................................91
Figure 3. 29: FT-IR analyses of the new (a) and recovered (b) catalyst. .....................92
Figure 3. 30: PXRD determination of the new (a) and recovered (b) catalyst. ............93

Figure 3. 31: Effect of different homogeneous catalyst on the reaction. .....................93
Figure 3. 32: Effect of different heterogeneous catalyst on the reaction. ....................95
Figure 3. 33: Effect of different atmospheres on reaction yield. ..................................96


LIST OF SCHEME
Scheme 1. 1: The photolysis of o-methyl dibenzyl ketone carried out inside the pores
of [Co3(4,40-BPhDC)3(4,40-bpy)] [30]. ..........................................................................9
Scheme 1. 2: The oxidation of cyclohexene [37]. ........................................................13
Scheme 1. 3: Simplified reaction for the acylation of anisole with acetyl chloride [36].
.......................................................................................................................................14
Scheme 1. 4: The catalytic activity of Cu-MOF-74 in some typically base-catalyzed
reactions, a) Knoevengel condensation rection. b) Micheal reaction [31]. ...................16
Scheme 1. 5: The coupling reaction of amines and -carbonyl aldehydes [39]. ..........17
Scheme 1. 6: The reaction between dibenzyl ether and 2-acetyl phenol utilizing CuMOF-74 catalyst [40]. ...................................................................................................17
Scheme 1. 7: The three-component coupling reaction of 2-pyridincarboxaldehyde,
piperidine, and phenylacetylene using Cu-MOF-74 catalyst [41]. ...............................18
Scheme 1. 8: The synthesis of imidazo[1,5-a]pyridines via oxidative amination of the
C(sp3)–H bond using Cu-MOF-74 [42]. .......................................................................18
Scheme 1. 9: The hydroacylation of 1-alkynes with glyoxal derivatives using the CuMOF-74 catalyst [43]. ...................................................................................................19
Scheme 1. 25: 1,5-benzodiazepine synthesis via cyclocondensation of 1,2-diamines
with ketones using MOF-235 as an efficient heterogeneous catalyst [48]....................21
Scheme 1. 26: Direct C-C coupling of indoles with alkylamides via oxidative C−H
functionalization using Fe3O(BDC)3 as a productive heterogeneous catalyst [49].......21
Scheme 1. 27: Direct arylation of benzoazoles with aldehydes utilizing metal–organic
framework Fe3O(BDC)3 as a recyclable heterogeneous catalyst [50]. .........................21
Scheme 1. 28: Synthesis of 2-alkenylazaarenes using the direct alkenylation of 2substituted azaarenes with carbonyls via C−H bond activation [51]. ...........................22
Scheme 1. 29: Oxidant-promoted formation of coumarins using Fe3O(BPDC)3 as an
efficient heterogeneous catalyst [52]. ............................................................................22
Scheme 1. 30: Direct C–N coupling of azoles with ethers via oxidative C–H activation

under metal–organic framework catalysis [53]. ............................................................23
Scheme 1. 31: One-pot oxidative synthesis of quinazolinones using Fe(BTC) as
efficient heterogeneous catalysts by Oveisi and co-workers [54]. ................................23
Scheme 1. 32: Cross-coupling of coumarin and N,N-dimethylaniline utilizing VNU20 as a heterogeneous catalyst [55]. ..............................................................................24
Scheme 1. 33: The cross-dehydrogenative coupling of 6-methylcoumarin with
mesitylene using the VNU-20 catalyst [56] ..................................................................24
Scheme 1. 10: The reductive N-heterocyclization of N-(2-nitrobenzoyl)azacycloheptane to prepare the corresponding azacycloheptano[2,1-b]-4(3H)-quinazolinone
[61].................................................................................................................................26
Scheme 1. 11: The Palladium-Catalyzed Reaction of o-Iodoanilines with
Carbodiimides and Carbon Monoxidea (a). The Palladium-Catalyzed
Cyclocarbonylation Reactions of o-Iodoanilines with Ketenimines (b) [62]. ..............27


Scheme 1. 12: One-pot condensation of anthranilic acid, ortho esters (or formic acid)
and amines (a) [63]. Synthesis of 4(3H)-quinazolinones using La(NO3)3.6H2O and
PTSA under solvent-free conditions (b) [64]. ...............................................................28
Scheme 1. 13: The synthesis of 3-aminoalkyl-2-arylaminoquinazolin-4(3H)-one and
3,3’-disubstituted bis-2-arylaminoquinazolin-4(3H)-ones [65]. ...................................28
Scheme 1. 14: Cu-catalyzed synthesis of quinazolinone derivatives (a) [66];
Microwave-assisted synthesis of quinazolinone derivatives via rapid iron-catalyzed
cyclization (b) [67]. .......................................................................................................29
Scheme 1. 15: Niementowski synthesis of modified quinazolinones [68]. ..................29
Scheme 1. 16: Synthesis of 2,3-disubstituted quinazolinones from N-(ohalophenyl)imidoyl chlorides or imidates [70]. ............................................................30
Scheme 1. 17: Synthesis of 3-substituted and 2,3-disubstituted quinazolinones via Cucatalyzed aryl amidation [71]. ......................................................................................31
Scheme 1. 18: Fe-catalyzed method for the synthesis of 2,3-diarylquinazolinones [72].
.......................................................................................................................................31
Scheme 1. 19: Oxidative radical skeletal rearrangement of 5-aryl-4,5-dihydro-1,2,4oxadiazoles into quinazolinones [73]. ...........................................................................32
Scheme 1. 20: Palladium-catalyzed carbonylative synthesis of quinazolinones with 2aminobenzamide (a) [74] with 2-aminobenzonitriles (b) [75]. .....................................32
Scheme 1. 21: Oxidative synthesis of quinazolinones [76]. .........................................33
Scheme 1. 22: The reaction between 2-aminobenzamide and benzyl alcohol using

Fe3O(BPDC)3 catalyst [77]. ...........................................................................................33
Scheme 1. 23: Synthesis of pyrido-fused quinazolinone derivatives via copper
catalyzed domino reaction [78]. ....................................................................................34
Scheme 1. 24: The reaction of 2-arylindoles with amines or ammoniums via BaeyerVilliger oxidation expansion [59]. .................................................................................34
Scheme 1. 34: Conventional method for construction of pyridine [89-92] ..................37
Scheme 1. 35: The Chichibabin reaction [87] ..............................................................37
Scheme 1. 36: The aza-Diels–Alder approach to pyridine derivatives [93] .................38
Scheme 1. 37: Synthesized 1-substituted 2-[(2S)-2-pyrrolidinyl] pyridine from Lproline [94] ....................................................................................................................39
Scheme 1. 38: Microwave-assisted organic synthesis of substituted pyridines from
1,3-dicarbonyl compounds and aldehydes [95]. ............................................................40
Scheme 1. 39: Synthesis of pyridines via palladium-catalyzed iminoannulation of
internal acetylenes [96]..................................................................................................40
Scheme 1. 40: Ring-closing metathesis strategy for pyridine synthesis using
acrylamide entry to synthesize pyridines [98]. ..............................................................41
Scheme 1. 41: Rhodium-catalyzed cycloaddition reaction for the formation of pyridine
derivatives [99, 100] ......................................................................................................42
Scheme 1. 42: Transition metal -catalyzed cross-coupling of activated pyridines ......42
Scheme 1. 43: Mn(III)-Mediated Reactions of Cyclopropanols with Vinyl Azides to
form 2,6-diphenylpyridine [103]. ..................................................................................43


Scheme 1. 44: Synthesis of functionalized pyridines via Cu-catalyzed threecomponent cascade annulation reaction [81]. ...............................................................44
Scheme 1. 45: The cyclization between (E)-acetophenone O-acetyl oxime acetate and
N,N-dimethylaniline utilizing iron-organic framework catalyst [104]. .........................44
Scheme 1. 46: Metal-free assembly of polysubstituted pyridines from oximes [105,
106]. ...............................................................................................................................45
Scheme 1. 47: Methodology synthesized 2,4,6, tri-substituted pyridines [110-113]. ..46
Scheme 1. 48: Coupling reaction of oximes acetates with toluene derivatives via
Csp3–H bond activation [80]. ........................................................................................47
Scheme 1. 49: Some recent methodology synthesized 2,4,6- trisubstituted pyridines

via oxime derivatives [80, 114-116]. .............................................................................48
Scheme 1. 50: The reaction between 2-phenylindole and 2-phenylethanamine utilizing
Cu2(dhtp) catalyst. .........................................................................................................50
Scheme 1. 51: The cyclization of ketoxime acetates and dibenzyl ether using VNU-20
as a heterogeneous catalyst. ...........................................................................................50
Scheme 2. 1: Synthetic reaction of Cu2(dhtp) or Cu-MOF-74 [34]. ............................53
Scheme 2. 2: Self-assembling synthesis of the reddish-yellow crystal (VNU-20) [44].
.......................................................................................................................................54
Scheme 3. 1: The reaction between 2-phenylindole and 2-phenylethanamine utilizing
Cu-MOF-74 catalyst.
64
Scheme 3. 2: The cyclization of (E)-acetophenone O-acetyl oxime acetate and
dibenzyl ether utilizing VNU-20 as a heterogeneous catalyst. .....................................78
Scheme 3. 3: Control experiments ..............................................................................103
Scheme 3. 4: Plausible reaction pathway....................................................................105


LIST OF TABLES
Table 1. 1: The Properties of Cu-MOF-74 [36]............................................................11
Table 2. 1: List of the utilized substances and their providers. ....................................51
Table 3. 1: The synthesis of 4(3H) quinazolinones containing different substituents.
75
Table 3. 2: Synthesis of 2,4,6-triphenylpyridines utilizing the VNU-20 catalysta. ......97


LIST OF ABBREVIATION
MOFs

Metal-organic frameworks

SBUs

Secondary building units

VNU

Vietnam national university

BBC

4,4′,4″-[benzene-1,3,5-triyl-tris(benzene-4,1-diyl)]tribenzoate

BTE

4,4′,4″-[benzene-1,3,5-triyl-tris(ethyne-2,1-diyl)]tribenzoate

CE

conventional electric

EC

electrochemistry

MC

mechanochemistry

US

microwave-assisted and ultrasonic

BDC

1,4-benzenedicarboxylate

BPDC

Biphenyl-4,4′-dicarboxylate

BTC

Benzene 1,3,5-tricarboxylate

NDC

2,6-naphthalenedicarboxylate

DABCO

1, 4-diazabicyclo [2.2. 2] octane

TEMPO

2, 2, 6, 6-tetramethylpiperidine-1-oxyl radical

BET

Brunauer-Emmett-Teller

BPY

4,4’-Bipyridine

DMF

N,N’-dimethylforamide

THF

Tetrahydrofuran

DCM

Dichloromethane

MAPs

Methoxyacetophenones

TFA

Trifluoroacetate

nbp

N-butylpyridinium

IL

Ionic liquid

DMSO

Dimethylsulfoxide

[bbim]+ Br-

1,3-n-dibutylimidazolium bromide

dppf

1, l'-bis-(dipheny1phosphino) ferrocene

GC

Gas chromatography

FID

Flame ionization detector

FT-IR

Fourier transform infrared

MS

Mass Spectrometry

NMR

Nuclear Magnetic Resonance

PXRD

Powder X-ray diffraction


AAS

Atomic absorption spectroscopy

SEM

Scanning Electron Microscope

SBU

Secondary building unit

TBHP

tert-butyl hydroperoxide

DTBP

Di-tert-Butyl peroxide

TGA

Thermal Gravimetric Analyzer

TEM

Transmission electron microscopy

H2(dhtp)

2,5-dihydroxyterephthalic acid

H2OBA

4,4′-oxybis(benzoic) acid

Dobdc

2, 5-dioxido-1, 4-benzenedicarboxylate

Acac

Acetylacetonate

Dpa

Di (2-pyridyl) amine

NIST

The National Institute of Standards and Technology

Literature Reviews

CHAPTER 1: LITERATURE REVIEW
1.1

Metal-organic frameworks (MOFs)

1.1.1 General introduction
Metal-organic frameworks (MOFs), also known as porous coordination polymers ,
are compounds consisting of metal ions clusters linked together by organic bridging
ligands with wide range of well – defined topology to form one-, two-, threedimensional structures [1]. MOFs have unusually large surface areas and tailorable
pore sizes. The most striking properties of MOFs are their large pore volumes that
have been unsurpassed by any other porous material to date. In comparison with other
solid matters such as zeolites, carbons and oxides, the porosity of MOFs have come up
to 90% free volume and the enormous internal surface areas have extended beyond
7000 m2/g (Figure 1. 1) [2]. For instance, MOF–200 and MOF–210 (Zn4O(BBC)2 and
(Zn4O)3(BTE)4(BPDC)3, respectively) act as an extensive class of crystalline materials
with the ultrahigh surface areas (4530 m2/g and 6240 m2/g, respectively) and porosities
(90% and 89% volume) [3].

Figure 1. 1: Progress in the synthesis of ultrahigh porosity MOFs. The values in
parentheses represent the pore volume (m3/ g) of these materials [4].

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An almost exponential growth of the structures of MOFs has been seen in the
Cambridge Structural Database (CSD) during the last decade. The combination of so
far unreached porosity, surface area, pore size and wide chemical inorganic–organic
composition recently has created a strikingly increasing trend each year for all
structure types (Figure 1. 2).

Figure 1. 2: Growth of the Cambridge Structural Database (CSD) and MOF entries
since 1972 [5]. The inset shows the MOF self-assembly process from building blocks:
metals (red spheres) and organic ligands (blue struts).
Transition metal ions such as copper, zinc, nickel, iron are frequently used as the
inorganic components of MOFs. For the organic linker, there are an extensive variety
of choices. Ligands with rigid backbones are often preferred, because the rigidity helps
to sustain the open-pore structure and easily predicts the network geometry for
expected application. The linkers can be neutral, anionic, or cationic. The neutral and
anionic organic linkers are most commonly use such as pyrazine and 4,4’-bipyridine
(bpy) [6] and carboxylates because they have the ability to aggregate metal ions into
clusters and therefore the frameworks are more stable [7]. Cationic organic ligands are
relatively little used, because of their low affinities for cationic metal ions [8].

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1.1.2 General methods for the synthesis of MOFs
During the last two decades, the synthesis of MOFs has attracted significant
attentions. The main goal in MOF synthesis was to establish the synthesis conditions
that lead to defined inorganic building blocks without decomposition of the organic
linker [9]. MOFs are often synthesized by means of solvothermal in which the
reactions are carried out in an organic solvent at high-temperature in closed vessels.

This method is relatively simple and can produce large-scale MOFs; However, it
typically takes long reaction times, from several hours up to several months,
depending upon the MOF of interest and the reaction solvents, reaction temperatures,
reagent concentrations, and other factors [8]. Besides that conventional electric (CE),
electrochemistry (EC), mechanochemistry (MC), microwave-assisted and ultrasonic
(US) methods have been employed (Figure 1. 3).

Figure 1. 3: Overview of synthesis methods, possible reaction temperatures, and final
reaction products in MOFs synthesis [10].

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Literature Reviews

1.1.3 Application of MOFs
MOFs with permanent porosity and their variety and multiplicity than any other
class of porous materials have made MOFs ideal candidates for storage of fuels
(hydrogen and methane), capture of carbon dioxide, (gas adsorption) and catalysis
applications [4].
In 1998, MOF-2 [Zn(BDC)] is the first carbon dioxide adsorption material [11] and
to date, MOF-200 with 2437 mg/g at 50 bar and 298 K have the best excess carbon
dioxide uptake [3]. The development in the chemistry of MOFs came in 1999, MOF5, the first robust and highly porous material , have gas adsorption measurements,
which revealed 61% porosity and a Brunauer- Emmett-Teller (BET) surface area of
2320 m2/g (2900m2/g Langmuir). These values are substantially higher than those
commonly found for zeolites and activated carbon [12]. MOFs have also been use to
separate toxic molecules, hydrocarbon and water from complex compounds. For
instance, Cu2(PZDC)2(Pyz) (PZDC = pyrazine-2,3-dicarboxylate; Pyz = pyrazine)
selectively takes up acetylene over carbon dioxide through hydrogen bonding between
acetylene and oxygen atoms on the MOF internal surface [13]. Besides that, the

melamine-MOFs were also used as an absorbent for the removal of heavy metal Pb(II)
from waste water [14]. One of the earliest examples of a dynamic separation was
performed

using

a

gas

chromatographic

[Zn2(BDC)2(BPy)]

to

separate

alkanes

such

column

filled

as n-pentane,

with

MOF-508

n-hexane,

2,2-

dimethylbutane, and 2-methylpentane [15]. In biomedical chemistry, iron-containing
BioMIL-1 MOF, which was built up from non-toxic iron and the therapeutically active
linker nicotinic acid, showed higher loading for nicotinic acid (up to 75%) as
compared to the native MOF structures and exhibited controlled drug delivery [16].
The most attractive application of MOFs is as heterogeneous catalysts for organic
chemical reactions due to the fact that they can be easily separated and recycled from
the reaction systems [17]. MOFs are composed entirely of strong bonds (e.g., C-C, CH, C-O, and M-O), they show high thermal stability ranging from 250° to 500°C[18].
However, these materials could not compare with zeolites in stability [19]. It has been
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Literature Reviews

a challenge to make chemically stable MOFs because of their susceptibility to linkdisplacement reactions when treated with solvents over extended periods of time
(days) [4]. Moreover, high open metal sites as well as abundant metal content in the
structure of MOFs give a higher catalytic activity than zeolites, in comparison [20]. So
MOFs have several unquestionable advantages included the variety of structures and
the ability for large-scale production [21].
Catalysis at the metal sites
Metal ions or clusters in the structure of numerous MOFs can directly coordinate to
the substrate to catalyze a chemical transformation, as well as, as-synthesized active
MOFs. Coordination of the substrate to the metal requires either an expansion of the
coordination sphere of the metal ion, or a displacement of one of the ligands (Figure
1. 4). However, the crystalline integrity do not collapse as a consequence of the local

distortions produced upon substrate coordination [22]. For example, employing copper
imidazolate, [Cu(im)2] and copper pyrimidinolate, [Cu(2-pymo)2] for aerobic liquid
phase oxidation of activated paraffins was investigation. In this study, the different
reactivities of [Cu(2-pymo)2] and [Cu(im)2] was described by principle DFT
calculations on MOF model clusters. According to that, [Cu(im)2] has a more
adaptable crystalline framework than [Cu(2-pymo)2], which allows that the copper
sites expand their coordination sphere from 4 to 5 upon interaction with ·OH radical
species. On the contrary, binding of the same radical to [Cu(2-pymo)2] produces the
displacement of one of the 2-pymo ligands from the coordination sphere around the
central Cu site. A hypothesis that a higher energy would be required in the case of
[Cu(2-pymo)2] to break a Cu-pyrimidine bond than in the case of [Cu(im)2] in which
only a rearrangement of the ligands is required to accommodate the ·OH radical leads
to the better performance of [Cu(im)2] than [Cu(2-pymo)2] in higher alkane
conversion, higher selectivity and low accumulation of alkylhydroperoxides in the
reaction medium [23].

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Literature Reviews

Figure 1. 4: Interaction of a substrate molecule, S, with a metal site, M, through (a)
expansion of the coordination sphere around the metal ion; or (b) (reversible)
displacement of one of the ligands [22].
Besides, MOFs with coordinatively unsaturated sites are MOFs in which one of the
coordination positions of the metal centers is occupied by a labile ligand, which can be
removed without causing the collapse of the crystalline structure. In most cases, the
labile ligands are solvent molecules that, when thermally removed, leave a free
coordination position in the metal, which become available for adsorbed substrates.
The correspoding metal center which will be prone to accept electron density from any

donor will behave as a Lewis acid center. When suitable oxidizing agents, such as O2,
H2O2 or hydroperoxydes, are present in the reaction medium, the resulting MOF can
contribute as redox catalyst [22]. For instance, the liquid phase cyanosilylation of
benzaldehyde using Cu3(BTC)2 was reported by Kclaus and co-workers. In this
situation, the Lewis acid copper(II) sites of the Cu2-paddle-wheel become accessible
for the coordination of the aldehyde. It was observed that physically and chemically
bound water molecules are easily removed from the host material by heating the
compound in vacuum (Figure 1. 5). The dehydration makes the copper coordination
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Literature Reviews

sites accessible for other molecules [24]. Other examples in previous literature were
Mukaiyama-aldol condensation [25], Friedel–Crafts benzilation [26], and the oxidation
of alcohols [27] sulfides, olefins, paraffins [28].

Figure 1. 5: Color changes during the dehydration of Cu3(BTC)2(H2O)3.xH2O to give
Cu3(BTC)2, and subsequent readsorption of the aldehyde to give
Cu3(BTC)2(C6H5CHO)x [24].
Catalysis at the organic linkers
MOFs catalyze a chemical reaction not only at the metal sites but also at the organic
linkers in some cases in which MOFs contain functional groups at the organic linker.
Therefore, the catalytic function is located at the organic linker and not at the metal
site. It is obvious that the linkers that form this type of MOFs need to contain two
different types of organic functional groups: coordinative functional groups, G1, that
coordinate to the metal sites to hold the crystalline framework; and reactive functional
groups, G2, which are not coordinated to the metals and will be responsible for the
catalytic properties of the material (Figure 1. 6). However, it is complicated to
generate MOFs with reactive functional groups free and accessible to catalytic

7


Literature Reviews

substrates. To meet the demand, the ligand used must be soluble and the functional
group must be resistant under the synthesis conditions [22]. A prototypic example of
MOFs having two types of functional groups is the Friedel−Crafts reaction between
pyrroles and nitroalkenes utilizing the material Nu-601 which contains 2D layers of Zn
paddlewheel dimmers connected to the urea ligand depicted and pillared with 4,40bipyridine. Nu-601 was found to be an active hydrogen-bond-donor that showed a
significantly higher rate of substrate consumption versus the control reaction [29].

Figure 1. 6: General structure and selected examples of ligands containing
coordinative and reactive functional groups [22].
Catalysis with the advantages of the pore sites
The prominent role of MOFs in heterogenerous catalysis fascinated scientists to
scrutinize this impact on the catalytic transformation. By decreasing mass transport
limitations, a high porosity of MOFs could facilitate the contact between the substrate
of the reaction and the catalytic sites. Academically, the pore system of the solid can
be used as either a host matrix to introduce additional catalytic species, or as the
nanometric reaction cavity where a chemical reaction takes place [22]. As a host
matrix, the regular system of channels and cavities of these solids can be used to
encapsulate various kinds of species, including metal or metal oxide nanoparticles or
molecular catalysts, this combine the properties of both the host and the guest.
Moreover, it can participate in the catalytic process contributing with additional
functionalities not provided by the encapsulated moieties, such as acid or basic sites
located at the metal nodes or the organic linkers. Besides, the nanometric reaction

8

Literature Reviews

cavity or the confinement space of the pore system can largely influence the product
selectivity, and this is more likely to occur when a substrate or product of the reaction
and the host matrix in which it is contained have similar dimensions. One example is
the reaction of o-methyl dibenzyl ketone inside the pores of the material [Co3(4,40BPhDC)3(4,40-bpy)]. In solution, the product distribution arises from the random
coupling of the two benzyl radicals, giving a 25, 50, 25% ratio of the three possible A–
A, A–B and B–B diarylethanes (Scheme 1. 1). However, when diffusion is restricted
due to confinement effects, the product distribution changes, favoring the asymmetric
A–B diarylethane arising from recombination of the geminate radical pair [30].

Scheme 1. 1: The photolysis of o-methyl dibenzyl ketone carried out inside the pores
of [Co3(4,40-BPhDC)3(4,40-bpy)] [30].
1.2

Introduction to Cu-MOF-74 as an efficient heterogeneous catalyst
Structure of Cu-MOF-74

Cu-MOF-74 belongs to a class of the M-MOF-74 (or M-CPO-27) series of
materials, being formed from a 2,5-dihydroxyterephthalic acid (dhtp4-) organic linkers
linking with metal cations (M = Cu, Fe, Mn, Co, Ni or Zn) which are of valence +2.
The structure of these MOF-74s, of general formula M2dobdc (dobdc4- = 2,5dioxidoterephthalate), consists of metal oxide chains connected by the dobdc4- linkers
to form a 3-D structure with honeycomb-like hexagonal that contains 1-D broad
channels [31]. The metal ions bond to oxygen atoms in square pyramidal geometry
with coordination number of five. After synthesis, the channels of MOF-74s are lined
with guest molecules such as water or DMF molecules because the metal cations
9