Synthesis and Investigation of Solid‐ and Solution‐State Structures of Nickel(II) Complexes with 1, 3‐Dimethyl‐5‐(arylazo)‐6‐aminouracil. Issue 36 (30th November 2016)

• Record Type: Journal Article
• Authors: Purkayastha, Atanu; Debnath, Diptanu; Roy, Subhadip; Bauzá, Antonio; Choudhury, Rupasree; Frontera, Antonio; Misra, Tarun Kumar
• Is Part Of: European journal of inorganic chemistry. Issue 36(2016)
• Page Start: 5585
• Page End: 5593
• Publication Date: 2016-11-30
• Subjects: Nickel -- Structure elucidation -- Noncovalent interactions -- Density functional calculations; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201601021
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : The (arylazo‐6‐aminouracil)nickel(II) derivatives [Ni II (DMA 3 U)2 ] [HDMA 3 U = 1, 3‐dimethyl‐5‐(arylazo)‐6‐aminouracil; arylazo = phenylazo (1 ), p ‐Me‐phenylazo (2 ), p ‐Cl‐phenylazo (3 )] have been synthesized and isolated in crystalline form. Single‐crystal X‐ray diffraction study of [Ni(1 )2 ] reveals that, in the complex, the metal center has a square‐planar environment. The intramolecular N–H/π and C–H/π interactions hold in the solid state as well as in poor hydrogen‐bond acceptor (HBA) solvents, but are disrupted in good HBA solvents. Crystal‐structure analysis further shows that the NH groups of the coordinated ligands are not available for hydrogen‐bonding interactions in the solid state, and this conclusion is corroborated by DFT calculations. Complexes exhibit multiple absorption bands in the UV/Vis region and TDDFT studies were performed to understand the origin of the ground‐state electronic absorptions. The complexes exhibit intense emission spectra in poor HBA solvents rather than in good HBA solvents. The association constant ( K asso ) values for complex HBA solvents, which were determined UV/Vis spectrophotometrically, range from 1.18 to 2.51m –1 . Abstract : Nickel(II) complexes of 1, 3‐dimethyl‐5‐(arylazo)‐6‐aminouracil ligands possess perfect square‐planar geometry. Crystallographic and DFT studies show that N–H/π and C–H/π interactions play important roles in the stabilization of the supramolecular assembly in the solid state, whereas in solution these interactions are present in chloroform and disrupted in DMSO due to the formation of hydrogen bonds.