Platinum (II), palladium (II), and nickel (II) complexes based on thiosalicylhydrazide and related ligands

Thiosalicylhydrazide and its derivatives were reacted with Pt(II), Pd(II), and Ni(II) metal precursors in methanol solvent in the presence of either pyridine or triethylamine base to produce metal complexes of these ligands with predominant monodentate coordination at the ligand S -atom. Non-covalent interactions (NCI) analysis of the crystal structure of one complex showed the presence of intramolecular interactions responsible for ligand spatial orientation. The reactions of thiosalicylhydrazide (HSC 6 H 4 CONHNH 2 , 1a H 2 ) and its derivatised ligands HSC 6 H 4 CONHR (where R = NCHC 6 H 4 - p -Cl; 1b H 2 , NCHC 6 H 4 - o -OH; 1c H 2 , NCHC 10 H 9 Fe; 1d H 2 and NHC 6 H 5 ; 1e H 2 ) with a variety of platinum(II), palladium(II), and nickel(II) centres were investigated with bond formation predominantly occurring through the deprotonated thiols as revealed by the X-ray crystal structure determination of the [Pt( 1b H) 2 (dppf)]·CH 2 Cl 2 (dppf = 1′1-bis(diphenylphosphino)ferrocene) complex. The complexes were characterised by NMR and FTIR spectroscopy, ESI mass spectrometry, and microelemental analyses. The tendency to form a S,N chelate in the reaction of [PtCl 2 (dppf)] with 1a H 2 , and an emerging isomerisation in [Pt( 1a H) 2 (PPh 3 ) 2 ] was confirmed by 31 P{ 1 H}NMR spectroscopy. Non-covalent interactions (NCI) analysis was carried out to demonstrate the occurrence of S···HN and O···HC attractive interactions in the [Pt( 1b H) 2 (dppf)]·CH 2 Cl 2 crystal structure which determine the spatial orientation of the two 1b H ligands. Hirshfeld surface analysis was used to visualise and quantify the various intermolecular interactions in the [Pt( 1b H) 2 (dppf)]·CH 2 Cl 2 crystal structure.