Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan.
Chemistry. 2011 Aug 22;17(35):9612-8. doi: 10.1002/chem.201101404. Epub 2011 Aug 9.
Cyanide-bridged metal complexes of [Fe(8)M(6)(μ-CN)(14)(CN)(10)(tp)(8)(HL)(10)(CH(3)CN)(2)]PF(6)⋅n CH(3)CN⋅m H(2)O (HL=3-(2-pyridyl)-5-[4-(diphenylamino)phenyl]-1H-pyrazole), tp(-) =hydrotris(pyrazolylborate), 1: M=Ni with n=11 and m=7, and 2: M=Co with n=14 and m=5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P2(1)/n. They have tetradecanuclear cores composed of eight low-spin (LS) Fe(III) and six high-spin (HS) M(II) ions (M=Ni and Co), all of which are bridged by cyanide ions, to form a crown-like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro- and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2, respectively. Ac magnetic susceptibility measurements of 1 showed frequency-dependent in- and out-of-phase signals, characteristic of single-molecule magnetism (SMM), while desolvated samples of 2 showed thermal- and photoinduced intramolecular electron-transfer-coupled spin transition (ETCST) between the [(LS-Fe(II))(3) (LS-Fe(III))(5)(HS-Co(II))(3)(LS-Co(III))(3)] and the [(LS-Fe(III))(8)(HS-Co(II))(6)] states.
氰桥联金属配合物[Fe(8)M(6)(μ-CN)(14)(CN)(10)(tp)(8)(HL)(10)(CH(3)CN)(2)]PF(6)⋅nCH(3)CN⋅mH(2)O（HL=3-(2-吡啶基)-5-[4-(二苯基氨基)苯基]-1H-吡唑，tp(-)=三(吡唑基)硼氢化物），1：M=Ni，n=11，m=7，2：M=Co，n=14，m=5）被制备。配合物 1 和 2 是同构的，结晶于单斜晶系 P2(1)/n 空间群。它们具有由八个低自旋（LS）Fe(III)和六个高自旋（HS）M(II)离子（M=Ni 和 Co）组成的十四核核心，所有这些离子都由氰化物离子桥接，形成一个冠形核结构。磁感性测量表明，分子内铁磁和反铁磁相互作用在 1 中和在 2 的新鲜样品中分别是有效的。1 的交流磁感性测量显示出与单分子磁体（SMM）特征相关的频率依赖的进相和出相信号，而 2 的去溶剂化样品则显示出[(LS-Fe(II))(3)(LS-Fe(III))(5)(HS-Co(II))(3)(LS-Co(III))(3)]和[(LS-Fe(III))(8)(HS-Co(II))(6)]状态之间的热和光诱导分子内电子转移耦合自旋转变（ETCST）。
