Bis (phosphine) bis (tellurocarboxylato)-palladium (II) and -platinum (II) complexes: synthesis and crystal structure

摘要

Bis (phosphine) bis (tellurocarboxylato)-palladium (II) and -platinum (II) [M(RCOTe)_2(PR'_3)_2] (M = pd or Pt; R = Bu~t, Ph, 4-MeC_6H_4, etc.; R' = Et or Ph), were synthesized in moderate to good yields by treating sodium tellurocarboxylates or O-trimethylsilyl telluroesters with [MCl_2(PR'_3)_2]. The platinum complexes with 2-methoxy-benzenecarbotelluroato ligands also were synthesized from [Pt(PR'_3)_4] with the corresponding diacyl ditelluride. The tellurocarboxylato complexes are yellow to orange or red crystals, and labile thermally and toward oxygen. The nickel analogues [Ni(RCOTe)_2(PR'_3)_2] (R' = Et or Ph) were obtained by similar fashion, but were too labile to isolate. X-Ray diffraction analysis of trans-[Pt(4-MeC_6H_4COTe)_2(PEt_3)_2] was carried out, and compared with those of the corresponding thio- and seleno-carboxylato complexes. These complexes crystallized in the same space group (P2_1/c) and are isostructural having a square-planar co-ordination geometry with thio- or telluro-carboxylato ligands which are unidentate.