Synthesis and Characterization of Platinum(II) Complexes with a Diazenecarboxamide‐Appended Picolyl‐Triazole Ligand

Abstract

AbstractThe coordination of the diazenecarboxamides, which were functionalized with the 1‐(2‐picolyl)‐1H‐1,2,3‐triazole moiety 1, to platinum(II) were studied, where K2[PtCl4] and cis‐[PtCl2(DMSO)2] were used as the platinum sources. The picolyl‐triazole (pictri) binding unit enabled chelation to the metal centre through the 1,2,3‐triazole N2 and the pyridyl nitrogen atoms under mild reaction conditions. When cis‐[PtCl2(DMSO)2] was used, with CH2Cl2 or CH3CN as the reaction solvents, the pure, stable diamminedichloridoplatinum(II) complexes 2 were isolated by filtration in 39 to 83 % yield. The products were structurally characterized in solution by 1H, 13C and 195Pt NMR spectroscopy. The 195Pt NMR chemical shifts for 2 appear in the region of –2203 to –2207 ppm. The structure of complex 2a was confirmed by single‐crystal X‐ray crystallography. The formation of the platinum complexes 2 was monitored using NMR spectroscopy. The complexation with cis‐[PtCl2(DMSO)2] in [D7]dmf proceeded through several intermediates, as indicated by the 195Pt NMR spectra with resonances in the range of –3055 to –2907 ppm. Similarly, the reaction of cis‐[PtCl2(DMSO)2] with diazenecarboxamide, which was functionalized with the nonchelating 1‐(2‐aminoethyl)‐1,2,3‐triazole derivative, was examined by NMR spectroscopy.