title: [Pressure-tuning infrared spectral study on the single-molecule-magnet manganese complexes].
abstract: The infrared spectra (IR) of single-molecule-magnet manganese complexes [Mn12O12 (O2CC6H4-3-Cl)16 (H2O)3 (3ClC6H4COH)].(3-Cl-C6H4CO2H)(I) and [Mn12O12(O2CCH2Br)16 (H2O)4]x4(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) x kbar(-1)) than in the high-pressure phase (0.29 cm(-1) x 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) x kbar(-1)) than in the high-pressure phase (0.23 cm(-1) x 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.
authors.affiliation: The State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
authors.forename: Zhen-hua
authors.initials: ZH
authors.lastname: Xu
authors.forename: Zhi-da
authors.initials: ZD
authors.lastname: Chen
authors.forename: Ian S
authors.initials: IS
authors.lastname: Butler
mesh_terms: D008280:Magnetics; D008345:Manganese / Q000737:chemistry*; D015394:Molecular Structure; D011312:Pressure; D013055:Spectrophotometry, Infrared / Q000379:methods*; D013696:Temperature
chemical_list: D008345:Manganese