X-ray crystal structure and vibrational spectra of hydrazides and their metal complexes. Part II. Hexaaquacobalt(II)bis(phthalhydrazidato)tetrahydrate

The hexaaquacobalt(II)bis(phthalhydrazidato)tetrahydrate, [Co(H2O)6](C8N2O2H5)2·4H2O is examined using single crystal X-ray diffraction analysis. The crystals are triclinic, space group P1¯, with a = 9.757(1), b = 10.955(2), c = 11.106(1), α = 100.79(2), β = 90.35(3), γ = 91.54(1) and Z = 2. In [Co(H2O)6](C8N2O2H5)2·4H2O, the cobalt(II) is coordinated by six water ligands and the [Co(H2O)6]2+ is associated with the two O-deprotonated phthalhydrazidato ions only by hydrogen bonds. The infrared and Raman spectra of phthalhydrazide (PH) and infrared spectra of deuterated derivative phthalhydrazide (PD) and of [Co(H2O)6](C8N2O2H5)2·4H2O are reported. The theoretical wavenumbers, infrared intensities and Raman scattering activities have been calculated using density functional (B3LYP) method with the 6-311++G(d,p) basis set. The calculated potential energy distribution has proved to be of great help in assigning the spectra PH, its deuterated derivative and [Co(H2O)6](C8N2O2H5)2·4H2O. The results from natural bond orbital (NBO) analysis for keto-hydroxy form of PH are presented.