A Novel Metal Organic Compound of Al(III): Synthesis, Crystal Structure, Spectroscopic and Theoretical Study

Abstract

A new mononuclear compound (dmpH)[Al(pydc)2]·3H2O 1, where pydcH2 = pyridine-2,6-dicarboxylic acid and dmp = 2,9-dimethyl-1,10-phenanthroline (as known neocuproine), has been synthesized and fully characterized. The crystallographic analysis revealed that the compound 1 crystallized in Monoclinic, P21/n space group with a = 9.2625(4) A, b = 18.2798(7) A, c = 15.6002(6) A, β = 94.233(2), Z = 4, V = 2634.17(18) A3. The asymmetric unit consists of [Al(pydc)2]– anion, one dmpH+ cation and three uncoordinated water molecules. Al(III) atom is coordinated in a distorted octahedral manner by two nitrogen and four oxygen atoms of pyridine-2,6-dicarboxylate ligand. Neocuproine is known as proton acceptor ligand. In the crystal structures of the complex extensive O–H···O, N–H···O and C–H···O hydrogen bonds as well as noncovalent interactions such as π–π and C–O···π stacking play important roles in stabilizing structures. Density functional theory calculations at B3LYP/6-311++G(d,p) level was carried out to calculate geometrical parameters of studied complexes. The electronic properties of the Al(III) complex and free (pydc)2− ligand have been investigated based on the natural bond orbital analysis. AIM methodology to verify interactions between counter ion and uncoordinated water molecules with Al complex is carried out as well. Novel synthesized Al(III) compound has supramolecular structure and its calculated geometrical parameters at B3LYP/6-311++G(d,p) level are in agreement with the experimental results.