Alkoxy-Bridged Dicopper(II) Cores Meet Tetracyanonickelate Linkers: Structural, Magnetic, and Theoretical Investigation of Cu/Ni Coordination Polymers.

Two heterometallic Cu(II)/Ni(II) coordination polymers, [Cu 2 (Hbdea) 2 Ni(CN) 4 ] n ( 1 ) and [Cu 2 (dmea) 2 Ni(CN) 4 ] n · n H 2 O ( 2 ), were successfully self-assembled in water by reacting Cu(II) nitrate with H 2 bdea ( N -butyldiethanolamine) and Hdmea ( N , N -dimethylethanolamine) in the presence of sodium hydroxide and [Ni(CN) 4 ] 2- . These new coordination polymers were investigated by single-crystal and powder X-ray diffraction and fully characterized by FT-IR spectroscopy, thermogravimetry, elemental analysis, variable-temperature magnetic susceptibility measurements, and theoretical DFT and CASSCF calculations. Despite differences in crystal systems, in both compounds, each dinuclear building block [Cu 2 (μ-aminopolyalcoholate) 2 ] 2+ is bridged by diamagnetic [Ni(CN) 4 ] 2- linkers, resulting in 1D ( 1 ) or 2D ( 2 ) metal-organic architectures. Experimental magnetic studies show that both compounds display strong antiferromagnetic coupling ( J = -602.1 cm -1 for 1 and -151 cm -1 for 2 ) between Cu(II) ions within the dimers mediated by the μ-O-alkoxo bridges. These results are corroborated by the broken symmetry DFT studies, which also provide further insight into the electronic structures of copper dimeric units. By reporting a facile self-assembly synthetic protocol, this study can be a model to widen a still limited family of heterometallic Cu/Ni coordination polymer materials with different functional properties.