TY - JOUR
T1 - A novel bis(trans-thiocyanate)iron(II) spin-transition molecular material with bidentate triaryltriazole ligands and its bis(cis-thiocyanate)iron(II) high-spin isomer
AU - Zhu, Dunru
AU - Xu, Yan
AU - Yu, Zhi
AU - Guo, Zijian
AU - Sang, Hai
AU - Liu, Tao
AU - You, Xiaozeng
PY - 2002
Y1 - 2002
N2 - Two novel complexes trans-[Fe(MBPT)2(NCS)2] (1) and cis-[Fe(mMBPT)2(NCS)2] (2) have been synthesized and their structure characterized at 293 K by single-crystal X-ray crystallography [MBPT (or mMBPT) = 4-p(or m)-methylphenyl-3,5-bis(pyridin-2-yl)-l,2,4 triazole]. Complexes I and 2 are isomers, and I crystallizes in the triclinic space group P with Z = 1, a = 9.120(3) Ä, b = 9.2563(18) Å, c = 11.576(2) Å, α = 76.256(15)°, β = 76.405-(18)°, γ = 84.983(19)°, and V = 922.1(4) Å3 in contrast to 2 in the monoclinic space group C2/c with Z = 4, a = 21.851(3) Å, b = 13.4113(15) Ä, c = 16.859(3) Å, β = 128.153(9)°, and V = 3885.0(9) Å3. Both complexes have a similar pseudo-octahedral [FEN6] core with the NCS- groups in the trans arrangement in I but cis in 2. Variable-temperature magnetic susceptibility and IR spectral measurements reveal that I shows an abrupt high-spin ↔ low-spin (HS ↔ LS) transition centered at T1/2 around 231 K, in contrast to 2 staying in a high-spin state in the observed temperature range of 75-300 K. The extended X-ray absorption fine structures (EXAFS) spectra confirm that the average Fe-N distance for the HS state in I is ≈0.2 Å longer than that of the LS state. Complex 1 represents the first spin-crossover iron(II) complex with triaryltriazole and trans-thiocyanate ligands.
AB - Two novel complexes trans-[Fe(MBPT)2(NCS)2] (1) and cis-[Fe(mMBPT)2(NCS)2] (2) have been synthesized and their structure characterized at 293 K by single-crystal X-ray crystallography [MBPT (or mMBPT) = 4-p(or m)-methylphenyl-3,5-bis(pyridin-2-yl)-l,2,4 triazole]. Complexes I and 2 are isomers, and I crystallizes in the triclinic space group P with Z = 1, a = 9.120(3) Ä, b = 9.2563(18) Å, c = 11.576(2) Å, α = 76.256(15)°, β = 76.405-(18)°, γ = 84.983(19)°, and V = 922.1(4) Å3 in contrast to 2 in the monoclinic space group C2/c with Z = 4, a = 21.851(3) Å, b = 13.4113(15) Ä, c = 16.859(3) Å, β = 128.153(9)°, and V = 3885.0(9) Å3. Both complexes have a similar pseudo-octahedral [FEN6] core with the NCS- groups in the trans arrangement in I but cis in 2. Variable-temperature magnetic susceptibility and IR spectral measurements reveal that I shows an abrupt high-spin ↔ low-spin (HS ↔ LS) transition centered at T1/2 around 231 K, in contrast to 2 staying in a high-spin state in the observed temperature range of 75-300 K. The extended X-ray absorption fine structures (EXAFS) spectra confirm that the average Fe-N distance for the HS state in I is ≈0.2 Å longer than that of the LS state. Complex 1 represents the first spin-crossover iron(II) complex with triaryltriazole and trans-thiocyanate ligands.
UR - http://www.scopus.com/inward/record.url?scp=0036193574&partnerID=8YFLogxK
U2 - 10.1021/cm010688u
DO - 10.1021/cm010688u
M3 - 文章
AN - SCOPUS:0036193574
SN - 0897-4756
VL - 14
SP - 838
EP - 843
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 2
ER -