Tin(IV) complexes of tridentate schiff bases having ONS donor systems

Synthesis of transition metal complexes containing a Schiff base ligand derived from 1,10-phenanthroline-2,9-dicarboxaldehyde and 2-aminobenzenethiol

“…It has been reported [20] that a metal is capable of forming dp-pp bands with ligands containing nitrogen as the donor atoms. The zinc(II) ion has its 4d orbitals completely vacant, and hence L ?…”

Synthesis and spectroscopic studies of organotin(IV) complexes of biologically active Schiff bases derived from sulpha drugs

“…12 These compounds give a & value of >2.1, which indicates a coordination number greater than four. Comparison of the isomer shift of these complexes with those already reported indicates the coordination number to be more than four, as these isomer shifts are much lower than those Retetrahedral tin.…”

Exploring oxorhenium ‘3+1’ mixed-ligand complexes carrying the S-benzyl-3-[(2-hydroxyphenyl)methylene]dithiocarbazate [ONS]/monothiol [S] donor set: synthesis and characterization

“…The tendency of the Schiff base to shift the equilibrium from thione form A to thiolo form B may be attributed to stabilization arising from the conjugation of the −C=N-N=C group upon coordination to the ReO(V) core [29]. Moreover, comparison of the 1 H NMR spectrum of the free ligand (1) with its ReO(V) complexes reveals that (i) the phenolic proton of the ligand disappears, (ii) the azomethine proton signal is shifted downfield [30], and (iii) the position of the SCH 2 proton resonance attributed to the S-benzyl group of (1), occurring at around δ 4.60 ppm, virtually remains unaltered during complexation. This supports the mode of coordination suggested by the IR data, with additional evidence that the sulfur atom in the CH 2 Ph group is not involved in coordination.…”