Nghiên cứu một số phân tử có chuyển pha spin

LUC  Nguyn Th Nguy


I HC QUI
TRƢỜNG ĐẠI HỌC KHOA HỌC TỰ NHIÊN




Nguyễn Thị Nguyệt Ánh



NGHIÊN CỨU MỘT SỐ PHÂN TỬ CÓ CHUYỂN PHA SPIN





LUC





i  N 2012

LUC  Nguyn Th Nguy


I HC QUI
TRƢỜNG ĐẠI HỌC KHOA HỌC TỰ NHIÊN




Nguyễn Thị Nguyệt Ánh



NGHIÊN CỨU MỘT SỐ PHÂN TỬ CÓ CHUYỂN PHA SPIN


: Vt
 :


LUC


NG DN KHOA HC: TS. NGUYN ANH TUN

i  





LUC  Nguyn Th Nguy


LỜI CẢM ƠN

L c nhn th
Nguyn Anh Tun, cng dn, bt
lu.
i li c
b  Thp, Khoa Vi
hc Khoa hc T t nhiu kin thc b 
Cui li c
  t thi gian qua.

 12 12 
Hc 
Nguyễn Thị Nguyệt Ánh

LUC  Nguyn Th Nguy


MỤC LỤC
LỜI CẢM ƠN
MỤC LỤC
Danh mục hình vẽ
Danh mục bảng biểu
Các ký hiệu & từ viết tắt
Chƣơng 1. MỞ ĐẦU 1
Chƣơng 2. PHƢƠNG PHÁP NGHIÊN CỨU 6
2.1. Gii thiu v t phi (DFT) 6
2.1.1.  7
2.1.2. : Thomas-





 8
2.1.3. 




-Kohn th nht 13
2.1.4. 









-Sham 16
 18
Chƣơng 3. Cấu trúc hình học, cấu trúc điện tử và đặc trƣng chuyển pha spin
của phân tử Mn(pyrol)
3
(tren) 19
3.1. Trp 19
3.1.1. Cc 19
3.1.2. Cn t 21
3.2. Tr 23
3.2.1. Cc 23
3.2.2. Cn t 24
3.3. Mt s a chuyn pha spin 26
3.3.1. S i c c 27
3.3.2. S chuy 28
3.3.3. S bing 31
Chƣơng 4. Cấu trúc hình học, cấu trúc điện tử và đặc trƣng chuyển pha spin
của phức chất [Fe

III
(salten)(mepepy)]BPh
4
34
4.1. Cấu trúc hình học 34


LUC  Nguyn Th Nguy


4.2. Cn t 36
4.3. S   38
4.3.1. S chuy 38
4.3.2. S a s chuy 40
Chƣơng 5. Cấu trúc hình học, cấu trúc điện tử, và đặc trƣng chuyển pha spin
của phân tử [Co(dioxolene)
2
(4-NO
2
-py)
2
] 41
5.1. Cc 41
5.2. Cn t 44
n pha spin 48
KẾT LUẬN 49
TÀI LIỆU THAM KHẢO 50

LUC  Nguyn Th Nguy


DANH MỤC HÌNH VẼ

c c Mn(pyrol)
3

ng. 1
 P c Mn
III
. 2
 chuyn tr ng ca
nhing cng c 4
ng dt b hin th c chuyn pha spin. 4
: Cc c Mn(pyrol)
3
 ng 

c theo tri xng Mn
ng. 19
n MnN
6
c Mn(pyrol)
3
(tren)  tr 20
    

  c  n t 





    
Mn(pyrol)
3
(tren)

 tr 21
t s qu  gn mc Fermi c Mn(pyrol)
3
(tren)
trong tr ti b m
3
. 22
3.5: S  t Mn(pyrol)
3
(tren)  tr, tr

c biu din b ti b m
3
. 23
3.6: Cn MnN
6
c Mn(pyrol)
3
(tren)  tr 23
 3.7:   

  c  n t 





    
Mn(pyrol)
3
(tren)

 tr HS. 25
t s qu  gn mc Fermi c Mn(pyrol)
3
(tren)
trong tr ti b m
3
. 26
3.9: S   Mn(pyrol)
3

(tren)  trHS, tr
c biu din b ti b m
3
. 26
c tranh m bin dn t c  ng th
th             n t   
Mn(pyrol)
3
(tren) khi chuyn pha gia trn
t so vi tr   (

c biu din b

LUC  Nguyn Th Nguy


n t so vi tr (

c biu din bng
i m ti b m
3
. 28
4.1: Cc ca ph
III
ng
 c b  
 34
: (a) 














 3d c Fe
III
, (b) Trng 
LS, (c) Tr  spin trong tr  spin
trong tr ti b m
3
. 37
: Bc tranh m bin dn t ca phc cht [Fe
III
(salten)(mepepy)]
 n t so vi tr (


c biu din bn t
so vi tr (

c biu din b 
t). M ti b m
3

38
5.1: (a) 









 [Co(dioxolene)
2
(4-NO
2
-py)
2

 c b  m,
i t dioxolene, (c) Phi t 4-NO
2
-py. 41
  C   n Co-N
2
O
4
c

[Co(dioxolene)
2

(4-NO
2
-py)
2
]
trn 42
  C   n Co-N
2
O
4
c

[Co(dioxolene)
2
(4-NO
2
-py)
2
]
tr 43
5.4: (a) 














 3d c [Co(dioxolene)
2
(4-NO
2
-
py)
2
], (b) Tr 45
 .5: Mt s qu o trng c   [Co(dioxolene)
2
(4-NO
2
-py)
2
] trong
tr 46
:   [Co(dioxolene)
2
(4-NO
2
-py)
2
], (a) Tr
LS, (b) Tr 46

LUC  Nguyn Th Nguy


DANH MỤC BẢNG BIỂU

B t MnN c Mn(pyrol)
3
(tren)  trng t
c t thc nghit. 20
B t Mn-N c Mn(pyrol)
3
(tren)  tr
c t thc nghit. 24
Bng 3.3 t Mnt NMnN (
o
)  trng
a  [Mn(pyrol)
3
c t kt qu c
nghi d  . 27
B N1N6 trong tr
LS

tr
HS
) c Mn(pyrol)
3
(tren). 31

B ng (eV) gia tr
Mn(pyrol)
3
(tren), bao g lch v 

xc
ng  32
Bng 4.1:    t Fe-  a phc cht [Fe
III
(salten)(Mepepy)]
 thc nghi 
t i giyc nghim. 35
Bng 4.2:  (m) ci t trong tr
 37
Bng 5.1: t (
o
) ca cn CoN
2
O
4
 tr
c t kt qu  liu thc nghi thc nghic in
 42

LUC  Nguyn Th Nguy


Các ký hiệu & từ viết tắt

AO: Qu  (Atomic orbital)
t phi (Density functional theory)
E: Tng
E
xc
i
HOMOn: Qu  th n i mc HOMO
HOMO: Qu  cao nht b chim (Highest occupied molecular orbital)
HS: Spin cao (High spin)
K
LS: Spin thp (Low spin)
LUMO: Qu  thp nh chim (Lowest unoccupied molecular
orbital)
LUMO+n: Qu  th n c LUMO
m: M
MO: Qu  (Molecular orbital)
n: i
Png kt cn t
S: Tng spin
SCO: Chuyn pha spin (Spin-crossover)
TS: Trn (Transition state)
U: Th n Coulomb

ng e

g
t
2g
)

: M  n t






LUC  Nguyn Th Nguy


1
MỞ ĐẦU

  
[4]



.1: 
3
(tren), 


d
4

 d
7


  kim
loi chuyn tip Mn
III
, vi cn t d
4
 ng hp
cht ca Mn  tr  c bao quanh bi 6
 ng phi t kin MnN
6
 bao
 , v Mn(pyrol)
3


LUC  Nguyn Th Nguy


phi t MnN
6
 c bao xung quanh b c
ch .1.
 o 3d c Mn b c
mc e
g
t
2g

: mc t
2g
ng thm 3 qu o d
xy
, d
yz
,

d
xz
; mc e
g

m 2 qu o d
z2
d
x2-y2
. Hing gic e
g

t
2g
g Mn
III
c quynh bi m
quan ging kt cn t c ch 1.2.
1.2:  P c Mn
III
.
e

g
tr t li v mng so vi vic
n t  bn t 3d ca ion Mn
III
nm  t
2g
, trong
n t p v S = 1, g
trp (Low spin, LS).
e
g
tr i v mng so vi vic
n t  n t 3d ca ion Mn
III
nm  trt
2g
n
t th  nm  tre
g
ng h bn t 3d ca ion
Mn
III
 
spin, HS).
 t gi nh   tn
ti  c hai tru kin nhi
c minh h 1.2.
 c t, vic          SCO

II


III
[20,37] 
Co
III

II


LUC  Nguyn Th Nguy



p cn t
(P) ph thuc ma nh kim loi chuyn
tip. Mt s  ca Fe
II

III
 ra r
II


III
 n t 3d d
6
 Fe
II
u
hin hi Co

III
va ion Co
III

ng gi nh  tr, hing SCO
hiy  nh Mn
II
vi cn t d
5
, hp cht
ng nh  trc li, v cha ion Fe
III

n t 3d y.
 


 

[3,24]


cao [15].


1.3(a)  
s ph thuc ca tr c SCO.  nhi thp,
 tn ti  trp LS,  nhi  tn ti  tr
spin cao HS.    chuyn tra nhi 
 nhi n nhi T

2
 chuyn t tr
m nhi xui T
2
 vn tn ti  tr
HS, phi tip tc gim nhi xung ti nhi T
1
< T
2
 mi tr v
tr nhi
2
 T
1

1


LUC  Nguyn Th Nguy



2
c g chuy nhit trong nhng
ng c n pha spin. Trong khong nhi t T
1

n T
2
  tn t

c bit nng nhi t T
1
n T
2
,
s d  chuyn t
trp sang trc lc minh h
1.3(c). V  c s d
nh  c thc hin bi nhi hoc


1.3: 

n pha spin, tng spin c thay 
t b chuyn m.
  
c ng dt b hin th.


LUC  Nguyn Th Nguy


1.4
 





 (DFT).

Trong bn ludt phi 
u cc, cn t chuyn pha spin ca mt
s  kim loi chuyn tip vi cn t m: 
[Mn(pyrol)
3
(tren)]      3d
4
, [Co(dioxolene)
2
(4-NO
2
-py)
2
] mt
 d
7
,  [Fe
III
(salten)(mepepy)]BPh
4

cho cd
5
.   
 Co nng thng cho vic thit k
ng h SCO mi.

LUC  Nguyn Th Nguy


C 2
PHƢƠNG PHÁP NGHIÊN CỨU

2.1. Giới thiệu về lý thuyết phiếm hàm mật độ (DFT)
ng t u h n t i gii
  ca h a 3N bin s. Cho
n hi i gii vng h 
n ti v   gii g
 mt gin ti
a h nhin t.
t phi (Density-
tip c hin thi nhiu ht
t hii dn tng cng t 
 t ca h n t , vt rm ct yu
t ca h in t c biu di
m n t ca h a 3 bin t a
3N bin t ng tm l
hic s dng nhiu nht) trong vit c

h vt liu t  cho ti cht r
 n t   t ca h n t c
 khi
ng t mi ra 
chng minh cht ch n tng ct phit
ng  trt phia
m n t  m hu ht va h
n t  n t. M
 c g n t  trn trong
 t DFT. T nhng vi s n tc

LUC  Nguyn Th Nguy


 n tc s dng ru qu
t rng t, vc,
khoa hc vt lic ghi nhn nha 
vit phi bng gi
1998. Ti  th  t phit
.
2.1.1. 
Tr























c gi










:
)1.1.2(), ,(), ,(
2
1
)(

2
11
1
2
1
2
2
NN
N
ji
ji
N
i
iexti
rrErr
rr
e
rV
m





































-Openheimer [1]. 







i, V
ext
 , E 




. 

, V
ext
 , tuy
V
ext
 

 
.
 (2.1.1) 



  tp h









nhau s 







a h 







:
)2.1.2(), ,(
1 M
RREE



 -(E
nn
c t
ng:

E
tot
= E + E
nn
(2.1.3)
M qua t  
gi ging hp chung




  ph thu . Trong nh
 xu  gi
c mn t [12,17]. K t i

LUC  Nguyn Th Nguy


 thut di qua mt
n mnh m [32,35].  p c
gii quyt v 



 

  
c[35],  (CC) [35]
ng t h[31].
nh vi d, 











  c l gi nhiu ht.
  t DFT, 









 c biu di t
phia m n t (E[(r)]) 





 p c
chuy nhiu hn t y cho

 nhiu ht v  ,



























 [11,23,28].  









phi



























 . 

, 

























phi











 E[(r)]. 










E[(r)].
2.1.2. : Thomas-










 1920 [8,9,10,36]. 






























.  : 







 ng
nhi v











 i h s 2







h
3






ng th hiu dnh bt
  cn t. 































 







 . 
 dn dt m

 


Thomas-Fermi.









u hydro.

LUC  Nguyn Th Nguy


)4.1.2()()(
2
2
2
2
rEr
r
e
Z
m










:
)5.1.2(
)(
)(
2
)(
)()(
2
)(
)()()(
2
)(
)(
2
)(
2
2
*
2
2
2
*
2
*2
2
*
2
2
2

*


  








energyattractionnucleuselectron
energykinetic
rd
r
r
Zerdr
m
r
rdr
r
e
Zerdr
m
r
rdr
r
e
Zrrdr

m
r
rdr
r
e
Z
m
rE
































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
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





(2.1.5)  -





















 r). 
 r). 



















 . 



 , 




 

(

), 





l V = l
3
, 











 N, 






0 K, 

 thi









, 






:
)6.1.2(
8
)(
8
),,(
2
2
2
222
2
2
R
ml
h
nnn
ml
h
nnn
zyxzyx







n
x
, n
y
, n
z
= 1, 2, 3, R 

, 
















 





1/8 th 







R n
x
, n
y
, n
z
). 



:
)7.1.2(
8
63
4
8
1
)(
2/3
2
23



















h
mlR




LUC  Nguyn Th Nguy













 + :
)8.1.2())((
8
4
)()()(
22/1
2/3
2
2



O
h
ml
g















g() 






















 (


) 





 N 



,
 







   

f().
 h-Dirac:
)9.1.2(
1
1
)(
)(






e
f

0 







:
)10.1.2(
,0
,1
)( 











asf
F
F




F
. 













 
F

  
F


. 




F








.














































:
)11.1.2(

2
5
8
2
4
)()(2
2/53
2/3
2
0
2/33
2/3
2
F
l
h
m
dl
h
m
dgfE
F




























 2 














 n t,








  


F







N 



V, 

:

)12.1.2(
2
3
8
)()(2
2/33
2/3
2
F
l
h
m
dgfN














LUC  Nguyn Th Nguy

thay 
F


(2.1.12) (2.1.11), :
)13.1.2(
8
3
10
3
3/5
3
3
3/2
2














l

N
l
m
h
E




(2.1.13) 















  =
N/l
3
NV 








. 










, :
)14.1.2(871.2)3(
10
3
,)(
)()3(
10
3
)(
8
3
10
3

][
3/22
2
3/5
2
3/53/22
3/5
3/2
2



































FF
TF
C
m
rdrC
m
rdr
rdr
m
h
T






 V   NV = (
r






. Chuyn v 



, :
)15.1.2()(][
3/5
rdrCT
FTF











 -


 ,  -














, 





. 

















 u hydro (



) 






:
)16.1.2(
)(
)()]([
3/5

 rd
r
r
ZrdrCrE
FTF















N 



, :
)17.1.2(
)()(
2
1)(
)()]([
21
21
21
3/5
rdrd
rr

rr
rd
r
r
ZrdrCrE
FTF






 
















:

)18.1.2(, ,, ,), ,,, ,( )(
111
2
111 NiiNiii
rdrdrdrdrrrrNr


 





 (2.1.17), 







 . 













  -



.

LUC  Nguyn Th Nguy


 ,  (2.1.17) 






.


























 . , 




 c t  ng nht, 













-



m yu tr
-Fermi. 

  
 ,   d 


.
Trong su

 , 



  lc b  






 -Fermi, 






 -Fermi-Dirac
(TFD) [6,28], Thomas-Fermi-Weizsacker (TFW) [28,38],  -
Fermi-Dirac-Weizsacker (TFDW hay TFD-[2,21,22,28,39,40].
























 -Fermi.  -




, 


















[6,28] 



. 


, :
)19.1.2(][][][

xTFTFD
EEE 



:
 
)20.1.2(7386.0,)(][][
3/1
3
4
3
3/4




xxDx
CrdrCKE









 

 

 
  





 . 
[14,28]. 














. 













 [38], 























 (1 + ar)e
ikr
, 

a  k 


. Hi

i v

-

:

LUC  Nguyn Th Nguy


)21.1.2(
)(
)(
8
1
][
2



 rd
r
r
T
W

















:
)22.1.2(][][][


WTFWTF
TTT 



1 

.
 ng s hiu chnh ti
v





 























[16].




















T[] 

c







 -Fermi-Dirac-






[2,21,22,39,40]. 












 (1964) [18].
 n t 





 n, 

 -







 t s g
i v







 ,  . 



 m
 E[], 
.  .
2.1.3. 




-Kohn th nht





















 -Kohn. 





, 






N



















), ,,(
21 N
xxx



(
),(
iii
srx


, s
i

 i gii c

 
thu

:
)23.1.2(
ˆ
 EH



 E  , 
H
ˆ

 . 





 -Openheimer , 









 (






LUC  Nguyn Th Nguy


)24.1.2(
1
2
1
)(
2
1
ˆ
111
2






operatorrepulsionelectronelectron
N
ji
ji
operatorattractionnucleuselectron
N
i
i
operatorenergykinetic
N
i
i
rr
rvH


















:
)5.1.2()(
1





M
i
i
Rr
Z
rv
















 ,
)(rv







   




.








(












) 








 :
)26.1.2(, ,,, ,), ,,, ,( )(
111
2
111 NiiiNiii
xdxddsxdxdxxxxNr


 













 x, y,  z. 






)(r



 


































)(r


. , 









)(r







. , 

















)(r



)27.1.2()(

 rdrN



,
)(r



[] 
-



V
ee
[]. 
)(r







)(rv

. 

  










.
Đi
̣
nh ly
́
Hohenberg -Kohn thứ nhất: 


)(rv








, 








, 










)(r



[18].

Vi

  

 [28]. , 






, 





u di














-V
ne
,












-



 V
ee
,  T 



 
)(r



, 














-.

LUC  Nguyn Th Nguy


   
 
)28.1.2()()(
)()(
1
)()(
1
)(
1
)( )(

1
)(
)( )(
)( )(
)(
)(
111
11
2
21
2
11
1
2
1
2
1
1
1
2
1
1
*



    
  

 

 






































rrvrd
rrvrd
N
rrvrd
N
r
N
rvrdr
N
rvrd
dsxdxdrvrdxdxddsrvrd
xdxdrvxdxdrv
xdxdrv
xdxdrvV
timesN
NNN
NNNNN
NNN
N
i
Ni
N

N
i
ine

  










y, u di











-g
qua
)(r



:
)29.1.2()()(][

 rdrrvV
ne



Ti u di











-



 V
ee



)(r


:
)30.1.2(),(
1

2
)1(1

1
2
)1(

1

2
)1(

1

1

2
1

1

2
1

1
2
1

21
21
21
321
2
21
21
321
2
21
21
1
2
21
)1(
1
2
1
1
2
21
1
1
2
1

1
*

  
  
 
  

 
 






































































rr
rr
rdrd
xdxddsds
NN
rr
rdrd
xdxddsds
rr
rdrd
NN
xdxd

rr
NN
xdxd
rr
xdxd
rr
xdxd
rr
xdxd
rr
V
N
N
N
timesNN
N
NN
N
N
ji
N
ji
N
N
ji
ji
ee












  











LUC  Nguyn Th Nguy




:
)31.1.2(
2
)1(
),(

321
2
21 N
xdxddsds
NN
rr

 





y, :
)32.1.2(][
)()(),()()(
),(
][
21
21
2121
21
21
21
21
21
21
termalnonclassicJ
rdrd
rr

rrrr
rdrd
rr
rr
rdrd
rr
rr
V
termalnonclassicenergyrep ulsionCoulomb
ee














  



  










J[]  . 










 ; 
 






.
T, Thomas-





















 , 












 T[]. 


 

,  












  nhc tip
t qua s g m thp c
m b , 















 



 T[c g


-Sham (KS) [19]. 




u dng 









.
2.1.4. 












-Sham








  















 









 , 

 hi




[19]. 

n th

 , 

  xu









:
)33.1.2()(
2
1
ˆ
11
2










N
i
is
N
i
i

rvH
