Magnetic, Spectroscopic and Thermal Study of [Cu(NO₃)(PyTz)₂](NO₃). A Copper(II) Complex Containing Thiazine Derivative Ligand

Abstract

The copper(II) complex [Cu(NO 3 )(PyTz) 2 ](NO 3 ) has been previously characterized means X-ray powder diffraction and now studied by IR spectroscopy, UV-Vis-NIR diffuse reflectance, magnetic susceptibility measurement, electronic spin resonance (ESR) and thermal analysis. The results are correlated with a distorted square pyramidal coordination around copper(II) ion rather than the cis-distorted octahedral stereochemistry of a CuN 4 OOЈ chromophore in good concordance with their structure. Likewise, in order to indicate towards what square pyramidal isomer the 947 complex is distorted, the method proposed by Carugo and Bisi has been applied to the structural data of [Cu(NO 3 )(PyTz) 2 ](NO 3 ). It is deduced that there is a large distortion from the trigonal bipyramid geometry, close to a square pyramid geometry, being produced almost exclusively through the B route of the Berry mechanism. 1 H-NMR (deuteriochloroform): δ 10.93 (s, 1H), 8.15 (d, J ϭ 4.82 Hz, 1H), 7.58 (t, J ϭ 7.71 Hz, 1H), 6.84 (m, 2H), 3.45 (t, J ϭ 5.12 Hz, 2H), 3.04 (t, J ϭ 5.92 Hz, 2H), 1.96 (m, 2H); 13 C-NMR (deuteriochloroform): δ 161.0, 146.1, 137.7, 119.1, 116.5, 41.8, 26.9, 22.0. UV-Vis (EtOH): λ max , nm; (ε, L mol Ϫ1 cm Ϫ1 ) 307 (17372), 267 (19249). Preparation of [Cu(NO 3 )(PyTz) 2 ](NO 3 )The preparation of the complex has been carried out as it is described by us [16]. The crystals were separated by filtration, washed with cold ether and air-dried. Found: C,