Experimental and theoretical investigation of octahedral and square-planar isothiocyanato complexes of Ni(II) with acylhydrazones of 2-(diphenylphosphino) benzaldehyde

Octahedral and square-planar isothiocyanato complexes of Ni(II) with the condensation derivative of 2-(diphenylphosphino)benzaldehyde and Girard's T reagent were synthesized and characterized by elemental analysis, IR spectroscopy and X-ray crystallography. Results of magnetic measurements for octahedral Ni(II) complex were also reported. In all the complexes the ligand is coordinated as tridentate via the phosphorus, the imine nitrogen and the carbonyl oxygen atoms while the remaining coordination positions are occupied with thiocyanato anions. Coordination of deprotonated phosphine ligand results in formation of square-planar complexes, while the octahedral complex was formed with protonated ligand. Reaction energetics with both forms of ligand were studied by the means of DFT and results were in complete agreement with experimental observations. Furthermore, ligand field splitting analysis gave the deeper insight in the relationship of the isolated complex coordination environment and protonation of the ligandThis work was supported by the Ministry of Education, Science and Technological development of the Republic of Serbia (Grant OI 172055). We thank the Slovenian Research Agency (ARRS) through program P-0175 for financial support and EN-FIST Centre of Excellence, Dunajska 156, 1000 Ljubljana, Slovenia, for using SuperNova diffractometer. The following organizations are thanked for financial support: the Ministerio de Ciencia e Innovacion (MICINN, project number CTQ2011-25086/BQU), and the DIUE of the Generalitat de Catalunya (project number 20145GR1202 and the XRQTC). Financial support from MICINN (Ministry of Science and Innovation, Spain) and the FEDER fund (European Fund for Regional Development) was provided by grant UNGI08-4E-00