Akitsu Takashiro, Einaga Yasuaki
Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama, Kanagwa 223-8522, Japan.
Inorg Chem. 2006 Nov 27;45(24):9826-33. doi: 10.1021/ic060783a.
Preparations, crystal structures, and spectral and magnetic properties of two new chiral one-dimensional cyano-bridged coordination polymers, [Cu(II)L2]M(II)(CN)].2H2O (M(II) = Ni(II) (1) and Pt(II) (2), L = trans-cyclohexane-(1R,2R)-diamine) have been presented. Complex 1 crystallizes in the monoclinic P2(1) space group with a = 9.864(4) A, b = 15.393(8) A, c = 7.995(4) A, beta = 110.32(3) degrees , V = 1138.4(10) A3, and Z = 2, while 2 crystallizes in the monoclinic P2(1) space group with a = 9.899(3) A, b = 15.541(4) A, c = 8.102(2) A, beta = 111.02(2) degrees , V = 1163.6(5) A3, and Z = 2. The unique zigzag cyano-bridged chains along the crystallographic b axis consist of alternate chiral [CuL(2)]2+ cations and square-planar [M(CN)4]2- anions. One side of the axial Cu-N(triple bond C) bond distances are 2.324(6) and 2.34(1) A with Cu-N[triple bond]C angles of 137.8(6) degrees and 138.2(9) degrees for 1 and 2, respectively. On the other hand, the opposite side of the axial Cu-N(triple bond C) bond distances are 3.120(8) and 3.09(1) A with significantly large bent Cu-N[triple bond]C angles of 97.9(5) degrees and 96.8(7) degrees for 1 and 2, respectively. The novel axial bonding features of extremely long semi-coordination Cu-N bonds are attributed to coexistence of pseudo-Jahn-Teller elongation and electrostatic interaction in the unique zigzag cyano-bridged chains. The characteristic bonding features with overlap between small 3d (Ni(II)) or large 5d (Pt(II)) and 3d (Cu(II)) orbitals results in larger shifts in XPS peaks of not only Cu2p(1/2) and Cu2p(3/2) but also Ni2p(1/2) and Ni2p(3/2) for 1 than those of 2, which is also consistent with weak antiferromagnetic interactions with Weiss constants of -5.31 and -5.94 K for 1 and 2, respectively. The d-d, pi-pi*, and CT bands in the electronic, CD, and MCD spectra for 1 and 2 in the solid state at room temperature are discussed from the viewpoint of magneto-optical properties.
本文报道了两种新型手性一维氰基桥联配位聚合物[Cu(II)L2]M(II)(CN)].2H2O（M(II) = Ni(II) (1) 和Pt(II) (2)，L = 反式环己烷-(1R,2R)-二胺）的制备、晶体结构以及光谱和磁性性质。配合物1结晶于单斜P2(1)空间群，a = 9.864(4) Å，b = 15.393(8) Å，c = 7.995(4) Å，β = 110.32(3)°，V = 1138.4(10) Å3，Z = 2；而配合物2结晶于单斜P2(1)空间群，a = 9.899(3) Å，b = 15.541(4) Å，c = 8.102(2) Å，β = 111.02(2)°，V = 1163.6(5) Å3，Z = 2。沿晶轴b轴的独特之字形氰基桥联链由交替的手性[CuL(2)]2+阳离子和平面正方形[M(CN)4]2-阴离子组成。对于1和2，轴向Cu-N(三键C)键距离的一侧分别为2.324(6) Å和2.34(1) Å，Cu-N[三键]C角度分别为137.8(6)°和138.2(9)°。另一方面，轴向Cu-N(三键C)键距离的另一侧分别为3.120(8) Å和3.09(1) Å，对于1和2，Cu-N[三键]C角度显著弯曲，分别为97.9(5)°和96.8(7)°。极长的半配位Cu-N键的新型轴向键合特征归因于独特之字形氰基桥联链中伪 Jahn-Teller 伸长和静电相互作用的共存。小3d（Ni(II)）或大5d（Pt(II)）与3d（Cu(II)）轨道之间重叠的特征键合导致1中不仅Cu2p(1/2)和Cu2p(3/2)，而且Ni2p(1/2)和Ni2p(3/2)的XPS峰位移比2中的更大，这也与1和2的反铁磁相互作用较弱一致，其魏斯常数分别为-5.31和-5.94 K。从磁光性质的角度讨论了1和2在室温下固态电子、CD和MCD光谱中的d-d、π-π*和CT带。
