Studies of spin-crossover complexes via solvo-thermal syntheses and their thermal relaxation of light excited kinetic phenomena
Date Issued
2004
Date
2004
Author(s)
CHEN, KOWA
DOI
zh-TW
Abstract
The novel complex Cis-[Fe(tzpy)2(NCS)2](1) has been synthesized successfully from spin crossover trans-[Fe(tzpy)2(NCS)2](2) isomer by solvothermal induced isomerization method. Single-crystal diffraction data was collected at 293 K by CAD-4 diffractometer. Complex (1) crystallizes in the monoclinic space group C 2/c with Z=4, a=14.828(4), b=11.485(5) Å ,c=15.071(2) Å, beta = 110.081(15) deg. The bond lengths of Fe-N are 2.249(4) Å, 2.197(4) Å, and 2.056(5) Å for complex 1 and 2.217(2) Å, 2.181(2) Å, and 2.097(3) Å for complex 2 at HS state. Solvothermal methods have provided rotes to otherwise inaccessible geometry isomers. Both complexes have a similar pseudo-octahedral [FeN6] core with the NCS- groups in the cis arrangement in 1 but trans in 2.
Another Dinuclear (N`, N1, N2 ,N``)2 Double bridging complex [Fe2(bpt)2(NCS)2(CH3OH)2] (3) and unique spin crossover 1D ladder complex [Fe2(bpt)2(NCS)2(bpy)2]•MeOH (4) have been synthesized successfully also by solvo- thermal syntheses from spin crossover trans-[Fe(abpt)2(NCS)2] complex.
Variable-temperature magnetic susceptibility measurement reveals that 1 and 3 staying in a high-spin state in the observed temperature range of 5-300 K. The 1D Spin-crossover complex 4 has a abrupt spin transition at 130 K and possesses unusual magnetic behavior.
It is interesting to note that the steric possible conformation can be realized by hydro-(solvo-)thermal syntheses and the differences of the crystal packing and [FeⅡN6] octahedron geometry between these iron (Ⅱ) complexes result in a dramatic change in their magnetic properties. Further studies on the origin of the discrepancy in the crystal field responsible for this result are currently in progress.
Subjects
自旋轉換
溶劑熱合成法
亞鐵錯合物
solvothermal
spincrossover
iron
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-93-R90223020-1.pdf
Size
23.31 KB
Format
Adobe PDF
Checksum
(MD5):fd48a740c556740ca8338f0ec7b11549