Crystal structure of bis(2,2′-bipyridyl)monochlorocopper(II) hexafluorophosphate monohydrate at 298 K and the electron spin resonance spectra of some bis(2,2′-bipyridyl)copper(II) complexes to 4.2 K

Abstract

The crystal structure of the title compound [Cu(bipy)₂Cl][PF₆]·H₂O (1)(bipy = 2,2′-bipyridyl) has been determined by X-ray diffraction, using diffractometer data collection. The structure was solved by the heavy-atom method and successive Fourier synthesis. Compound (1) crystallises in the monoclinic space group P2₁/n with a= 21.403(5), b= 12.235(3), c= 8.599(2)Å, β= 92.68(2)°, and Z= 4. The CuN₄Cl chromophore involves a near-regular trigonal bipyramidal stereochemistry, but with a significant distortion of the three in-plane angles from 120°(115.7, 123.8, and 120.5°). The poly-crystalline and single-crystal e.s.r. spectrum of (1) and a number of other 2,2′-bipyridyl complexes with [Cu(bipy)₂X]ⁿ⁺ cations (X = Cl or I, n= 1; X = NH₃, n= 2) are reported between 300 and 4 K. The molecular g tensors are consistent with a near-regular trigonal bipyramidal or square pyramidal distorted trigonal bipyramidal stereochemistry. As the e.s.r. spectra do not change significantly with temperature a dynamic behaviour in the sense of the pseudo-rotation of the Berry–Twist mechanism is not considered to operate.