Organometallic palladium and platinum complexes with strongly donating alkyl coligands – Synthesis, structures, chemical and cytotoxic properties

Labile Pd-sulphur and Pt-sulphur bonds in organometallic palladium and platinum complexes [(COD)M(alkyl)(S-ligand)]n+—A speciation study

“…The complexes [(COD)Pd(Me)Cl] [45,74] reported [50]. All other chemicals were purchased from commercial suppliers and were used without further purification. ]…”

“…For a more defined approach to assess the binding strength of various sulphur ligands (with or without biological relevance), complex scaffolds [(terpy)Pt] 2+ (terpy = 2,2′:6,2″-terpyridine) [16,23,[31][32][33][34][35][36][37][38] and [(dien)Pt] 2+ (dien = diethylene-triamine) [22,[36][37][38][39][40] with only one coordination site, have been frequently studied, in the latter case also the Pd derivatives [36][37][38]41,42]. Recently, we have demonstrated the suitability of the [(COD)M(R)] (M = Pt or Pd; R = alkyl) fragment to coordinate various ligands [43][44][45][46][47][48][49][50][51]. For the platinum derivatives multinuclear NMR spectroscopy in addition to the determination of molecular structures has allowed an excellent insight into the binding between platinum and the introduced ligands [43][44][45][46][49][50][51].…”

“…Recently, we have demonstrated the suitability of the [(COD)M(R)] (M = Pt or Pd; R = alkyl) fragment to coordinate various ligands [43][44][45][46][47][48][49][50][51]. For the platinum derivatives multinuclear NMR spectroscopy in addition to the determination of molecular structures has allowed an excellent insight into the binding between platinum and the introduced ligands [43][44][45][46][49][50][51]. From the 1 H-195 Pt coupling constant of the trans-oriented olefin proton the bond strength could be quantified quite reliably.…”

“…For the palladium analogues [(COD)Pd(Me)] [45,46,48] only bonding distances from molecular structure determinations give such insight. However, it became also evident, that bond distances are not only the result of metal to ligand binding, but is also influenced by crystal packing effects.…”

“…The motivation to start this study comes from the fact that organometallic derivatives of the [(COD)Pt(R)X] motif have shown marked antiproliferative activity with X = Cl, alkynyl, or alkyl [43][44][45][46]. Recently, we added the thiolate ligand SC 6 F 4 H-4 [50] to this series on which we report herein.…”