Tuning of electronic properties of one-dimensional cyano-bridged CuII-NiII, CuII-PdII, and CuII-PtII bimetallic assemblies by stereochemistry of ligands
Abstract: Preparations, XPS and electronic spectroscopy, and magnetism of seven new one-dimensional cyano-bridged coordination polymers, chiral [Cu(RR-chxn)2][Pd(CN)4]·2H2O (1), [Cu(trans-chxn)2][M(CN)4]·2H2O (2, 4, and 6 for M=Pd, Ni, and Pt), and [Cu(cis-chxn)2][M(CN)4]·2H2O (3, 5, and 7 for M=Pd, Ni, and Pt) (RR-chxn=cyclohexane-(1R,2R)-diamine, trans-chxn=racemic trans-cyclohexane-(1,2)-diamine, and cis-chxn=racemic cis-cyclohexane-(1,2)-diamine) have been reported in view of tuning of their electronic properties by stereochemistry of chxn ligands and metal-substitution. Comparison of Cu 2p1/2 and 2p3/2 peaks of XPS and broad d–d bands around 18000cm−1 of electronic spectra are described systematically for 1–7. Variable-temperature magnetic measurement shows that complexes 1–7 indicate weak antiferromagnetic interactions via cyano-bridges. Because of semi-coordination coupled with pseudo Jahn–Teller elongation and electrostatic interaction for 1, the axial Cu–N coordination bond distances of 2.330(7) and 3.092(8)Å are considerably longer than those of equatorial ones in the range from 2.016(6) to 2.030(6)Å. The former bond distances of 1 are intermediate values among the related Ni (2.324(6) and 3.120(8)Å) and Pt (2.34(1) and 3.09(1)Å) complexes. [Copyright 2008 Elsevier] Copyright of Inorganica Chimica Acta is the property of Elsevier Science Publishers B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts)