Novel Mononuclear Divalent Zinc, Cadmium and Mercury Complexes of Tridentate Hydrazone Ended by Thiophene Ring

New hydrazone derivative, namely (Z)-4-((3-cyano-4,6-dimethyl pyridine-2-yl)amino)-N'-(thiophen-2-ylmethylene)benzohydrazide (H2BTH) and its mononuclear Zn(II), Cd(II) and Hg(II) complexes were prepared and characterized by conventional measurements. Infrared spectral data confirmed that the hydrazone coordinates to metal ion as neutral NS or NO. The structure of Cd(II) complex was further studied by x-ray powder diffraction. The density functional theory (DFT) based quantum chemical calculations were accomplished at B3LYP/6-level of theory andMuilikan atomic charge in a companion with global and local reactivities and various energetic values have been calculated at the selected atoms, and the reactive sites have been assigned on the surface of the molecules through molecular electrostatic potential (MEP) map. TGA and DrTGA were used to establish some compounds' thermal stability, and the kinetic parameters of activation such as ΔG*, ΔH*, and ΔS* were determined. Moreover, all investigated compounds were screened for antimicrobial and DNA binding activities.

Synthesis of Newer Mercury(II) Complexes of Meso-Tetraaryl-21,23-Dithiaporphyrins

Due to the larger size of hetero atom and poor binding with metals, N2X2 type of core modified porphyrins show lesser tendency to form metal complexes. Mercury(II) complexes of symmetrical and unsymmetrical meso-tetraaryl-21,23-dithiaporphyrins are synthesized and characterized by the reaction of corresponding meso-tetraaryl-21,23-dithiaporphyrins with mercuric acetate in chloroform/methanol. These mercury complexes are well characterized by their UV-Visible spectra, fluorescence spectra, 1H NMR, 13C NMR and elemental analysis. Soret bands of mercury complex of unsymmetrical 5,20-bis-(4′-methoxyphenyl)-10,15-bisphenyl-21,23-dithiaporphyrin appeared at 442 nm and 462 nm whereas Q band appeared at 516 nm, 560 nm, 620 nm and 714 nm. Appearance of four Q bands is characteristic for this mercury complex of N2X2 type of core modified porphyrins. Mercury complex of unsymmetrical 5,20-bis-(4′-methoxyphenyl)-10,15-bisphenyl-21,23dithiaporphyrin is an excellent fluorescent molecule and showed fluorescence spectrum at 722 nm. These core modified porphyrin complexes provides a good coordination examples of mercury complexes of 21,23-dithiaporphyrins that can be used in sensing applications.

The η1-H–C⋯Hg agostic interactions in the mercury complexes of N-confused porphyrin

The bond path for the η1-H(17)–C(17)⋯Hg agostic interactions in 4–9 was a through-space interaction [Hg⋯C(17)] and a through-bond interaction [Hg⋯H(17)].