Synthesis, X-ray crystal structures and properties of complex salts and sterically crowded heteroleptic complexes of group 10 metal ions with aromatic sulfonyl dithiocarbimates and triphenylphosphine ligand

Two new complex salts of the form (Bu4N)2[Ni(L)2] (1) and (Ph4P)2[Ni(L)2] (2) and four heteroleptic complexes cis-M(PPh3)2(L) [M = Ni(II) (3), Pd(II) (4), L = 4-CH3OC6H4SO2NCS2] and cis-M(PPh3)2(L′) [ M = Pd(II) (5), Pt(II) (6), L′ = C6H5SO2NCS2] were prepared and characterized by elemental analyses, IR, 1H, 13C and 31P NMR and UV–Vis spectra, solution and solid phase conductivity measurements and X-ray crystallography. A minor product trans-Pd(PPh3)2(SH)2, 4a was also obtained with the synthesis of 4. The NiS4 and MP2S2 core in the complex salts and heteroleptic complexes are in the distorted square-plane whereas in the trans complex, 4a the centrosymmetric PdS2P2 core is perforce square planar. X-ray crystallography revealed the proximity of the ortho phenyl proton of the PPh3 ligand to Pd(II) showing rare intramolecular C–H⋯Pd anagostic binding interactions in the palladium cis-5 and trans-4a complexes. The complex salts with σrt values ∼10−5 S cm−1 show semi-conductor behaviors. The palladium and platinum complexes show photoluminescence properties in solution at room temperature.