A new trinuclear zinc(II) complex and a heptacoordinated mononuclear cadmium(II) complex with a pyrimidine derived Schiff base ligand: Syntheses, crystal structures, photoluminescence and DFT calculations

作者：Das Kinsuk; Jana Atanu; Konar Saugata; Chatterjee Sudipta; Mondal Tapan Kumar; Barik Anil Kumar^*; Kar Susanta Kumar

来源：Journal of Molecular Structure, 2013, 1048: 98-107.

DOI：10.1016/j.molstruc.2013.05.020

• Pyrimidine-derived Schiff base ligand
• Trinuclear zinc(II)
• Heptacoordinated cadmium(II)
• X-ray crystal structure
• Spectral study

The new N-6 donor hexadentate Schiff base 2,4-bis [2-(pyridine-2-ylmethylidene) hydrazinyl] pyrimidine (L), its trinuclear Zn(II) complex, [Zn-3(L)(2)Cl-6] (1) and mononuclear heptacoordinate Cd(II) complex [Cd(L)(H2O)(2)](ClO4)(2) (2) have been synthesised and characterised by crystallographically and spectroscopically. Complex 1 is featured by the triangular arrangement of three zinc atoms where the neighbouring Zn atoms are linked via half portion (N-3 chromophore) of the same ligand molecule. In 1, the ligand molecules behave as hexadentate ones (employing both pyrimidine nitrogen atoms as active donor centres) to create the octahedral environment around Zn(II). The central and terminal Zn(II) atom has N-6 and N3Cl3 chromophores respectively. In 2 the same ligand (L) behaves as pentadentate one (ignoring one pyrimidine nitrogen in the coordination process) to produce a pentagonal bipyramidal geometry with two apical water molecules. The geometries of both complexes were optimised in the singlet state by DFT method. The TDDFT calculations have been done on the optimised geometries to understand the electronic structure and spectral transition in the complexes. Complex 1 exhibits intraligand (1)(pi -%26gt; pi*) fluorescence in aqueous methanol solvent at room temperature.

• 出版日期2013-9-24