Synthesis, structure and spectral investigation of hydrogen bonded helical chain in mixed ligand Cu(II) pyrimidone complex

A simple mono-aqua-dichloro copper(II) pyrimidone complex has been synthesized and characterized using various spectral techniques such as Infrared and Raman in addition to the single crystal X-ray diffraction. The single crystal X-ray analysis carried out for the complex under study brings out the fact that there are two molecules in the unit cell with parameters a = 9.657(2); b = 3.857(2); c = 10.781(2); α = 90°; β = 107.781°; γ = 90°; V = 382.891 and are crystallized in monoclinic crystal system with Pn space group. In solid state the molecules are interconnected through strong hydrogen bonding [O4⋯H21-O2W = 2.644 Å; O4⋯H21 = 1.853 Å; ∠O4⋯H21-O2W = 172.87°;] formed between the coordinated water molecule (O2W) and the exocyclic ketonic oxygen of the pyrimidone ring (O4). This H-bonding interaction causing a twist in the C1 = O1⋯H21 segment [∠C1 = O1⋯H21 = 122.29°] in combination with weak π-π stacking interaction (3.857 Å) of the adjacent pyrimidone rings brings the single stranded helical chain which possesses both P and M sense of supramolecular helical assembly. The internal and external modes of vibrations of the crystal under study have been estimated and discussed by applying group theoretical methods.