Copper(II) solvatochromic complexes [Cu(acac)(N^N)(ligand)]BPh4 with various axial ligands. Correlation between coordination geometries and d–d transition energies (acac=acetylacetonato, N^N=1,10-phenanthoroline, 2,2′-bipyridyl)

Year: 2013 DOI: 10.1016/j.poly.2012.09.063

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Ryo Horikoshi, Yusuke Funasako, Takeshi Yajima, Tomoyuki Mochida, Yoji Kobayashi, Hiroshi Kageyama.   Polyhedron, 2013, 50, 66-74.


A series of copper(II) solvatochromic complexes [Cu(acac)(N^N)(ligand)]BPh4 (acac = acetylacetonato; N^N = 1,10-phenanthoroline (1), 2,2′-bipyridyl (2); ligand = HMPA, pyridine, DMSO, DMF, MeOH, acetone, and MeCN) have been synthesized and their coordination geometries were crystallographically investigated. The solvent-coordinated cations, adopting a five-coordinate square-pyramidal structure, formed head-to-tail dimers via π⋯π interactions. Solid-state absorption studies revealed that their d–d transition energies are correlated with the donor number of the axial ligands. A linear correlation was found between the d–d transition energies and the Cu–O (axial ligands) distances in the solid-state, revealing the role of the coordination environment on the d–d transition energies in the copper(II) solvatochromic complexes.