EPR study of electron transfer and group transfer in organoplatinum(II) and (IV) compounds

摘要: Chelate complexes between the 1,4-diazabuta-1,3-diene ligands RNCH–CHNR = R–DAB (R = alkyl, aryl) and organoplatinum fragments PtMe2, PtMe4 PtMes2 (Mes = mesityl) can be reversibly reduced to paramagnetic compounds, formulated as platinum(II) or (IV) species bound by radical anion (R-DAB˙–). EPR studies in fluid frozen solution support this assignment; however, metal contribution singly occupied MO is higher for PtII than PtIV systems. Comparison with related of main group transition element series reveals that even organoplatinum(IV) compounds exhibit a relatively high degree ligand-to-metal spin transfer evident from small 1H(CH) large 14N 195Pt hyperfine coupling constants. The tetramethylplatinum(IV) are photoreactive; platinum-containing primary dissociation product platinum–carbon σ bond homolysis has been detected spectroscopy using But-NO trap reagent during irradiation. Group reactivity also noted anions where conversion [(R-DAB)PtMe2]˙– → [(R-DAB)PtMe4]˙– could monitored spectroscopy.