X-ray crystal structure and vibrational spectra of hydrazides and their metal complexes. Part I. Catena-poly[di-μ-aqua-(μ-maleic hydrazidato-O)sodium] hydrate

The catena-poly[di-μ-aqua-(μ-maleic hydrazidato-O)sodium] hydrate, [Na(MH) (H2O)2]n·H2O is examined using single crystal X-ray diffraction analysis. The crystals are monoclinic, space group C2/c, with a = 14.321(4), b = 16.114(5), c = 6.547(1) Å, β = 104.11(2) and Z = 4. In title complex, each sodium ion is coordinated by two oxygen atoms of two water molecules, one oxygen atom of the maleic hydrazidato, two oxygen atoms of two water molecules from an adjacent [Na(MH)(H2O)2] unit and one oxygen atom of the maleic hydrazidato from an adjacent [Na(MH)(H2O)2] unit too. It is interesting that the sodium ion is not bonded by O-deprotonated oxygen atom but by carbonyl oxygen atom of maleic hydrazidato. The infrared and Raman spectra for maleic hydrazide (MH), its deuterated derivative (MD) and [Na(MH)(H2O)2]n·H2O 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) for MH and MD and 6-311++G(d,p)/LanL2DZ for [Na(MH)(H2O)2]n·H2O basis sets. The calculated potential energy distribution has proved to be of great help in assigning the infrared and Raman spectra maleic hydrazide, its deuterated derivative and [Na(MH)(H2O)2]n·H2O. The isotope replacements were very helpful in correlation of observed bands and of the theoretically calculated normal vibrations. The results from natural bond orbital (NBO) analyses for keto-hydroxy, diketo and dihydroxy forms of MH as well as for the theoretical model of [Na(MH)(H2O)2]n·H2O are compared.