单分子磁体-锰配合物的高压红外光谱研究  

Pressure-Tuning Infrared Spectral Study on the Single-Molecule-Magnet Manganese Complexes

作　　者：许振华[1] 陈志达[1] Ian S Butler 

机构地区：[1]北京大学化学与分子工程学院 [2]Department of Chemistry

出　　处：《光谱学与光谱分析》2004年第6期663-665,共3页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金 (50 2 0 30 0 1;2 0 0 2 30 0 5和G1 9980 61 30 7)资助项目

摘　　要：研究了单分子磁体锰配合物Ⅰ :[Mn1 2 O1 2 (O2 CC6 H4 3 Cl) 1 6 (H2 O) 3(3 Cl C6 H4 CO2 H) ]·(3 Cl C6 H4 CO2 H)和配合物Ⅱ :[Mn1 2 O1 2 (O2 CCH2 Br) 1 6 (H2 O) 4]·4 (CH2 Cl2 )的高压红外光谱 ,两者不同的压力诱导相转变的压力 (配合物Ⅰ :2 5～ 2 9kbar,配合物Ⅱ :2 9～ 35kbar)被观察到 ,两者均为二级压力诱导相转变。认为在压力诱导相转变时 ,也发生了配合物高自旋向低态自旋态的转变。配合物Ⅰ的平均压力灵敏度不同于通常情况 ,它在低压相区的平均压力灵敏度 (0 19cm- 1 ·kbar- 1 )比高压相区 (0 2 9cm- 1 ·kbar- 1 )低。而配合物Ⅱ与通常情况相似 ,在低压相区平均压力灵敏度 (0 34cm- 1 ·kbar- 1 )比高压相区 (0 2 3cm- 1 ·kbar- 1 )为高 ,即在高压相区的可压缩性比低压相区小。The infrared spectra (IR) of single-molecule-magnet manganese Complexes [Mn-12 O-12 (O2CC6H3-3-Cl)(16) (H2O)(3) (Cl-3-C-6 H4CO2H)](.)(3-Cl-C6H4CO2H) (I) and [Mn-12 O-12 (O2CCH2Br)(16) (H2O)(4)](.)4(CH2Cl2) (II) were studied at high external pressure. The different pressure-induced phase transition pressures were observed for both complexes (complex I, 25-29 kbar) and (complex II, 29-35 kbar). Both were second-order pressure-induced phase transition. The possible changes from higher spin to lower spin happened near the phase transition pressure following the changes of their structures when undergoing the high pressures. The average value of pressure sensitivities in the low-pressure phase is unusually smaller (0.19 cm(-1) (.) kbar(-1)) than in the high-pressure phase (0.29 cm(-1) (.) kbar(-1)) in the complex I. On the contrary, the average value of the pressure sensitivities in the low-pressure phase is higher (0.34 cm(-1) (.) kbar(-1)) than in the high-pressure phase (0.23 cm(-1) (.) kbar(-1)) in the complex II as usually, which means that the possibility of compression is lower in the high-pressure phase than in the low-pressure phase.

关 键 词：单分子磁体 锰配合物 高压红外光谱 压力诱导相转变 磁性材料 

分 类 号：TM27[一般工业技术—材料科学与工程] O614.711[电气工程—电工理论与新技术]