Synthesis of [Pt(CO)(dppm)] and [Pt(CO)(dppm)] Heteroleptic Chini-type Platinum Clusters by the Oxidative Oligomerization of [Pt(CO)(dppm)].

The reactions of [Pt(CO)] with CH(PPh) (dppm), CH═C(PPh) (P^P), and Fe(CHPPh) (dppf) proceed via nonredox substitution and result in the heteroleptic Chini-type clusters [Pt(CO)(dppm)], [Pt(CO)(P^P)], and [Pt(CO)(dppf)], respectively. Conversely, the reactions of [Pt(CO)] with PhP(CH)PPh (dppb) and PhPC≡CPPh (dppa) can be described as redox fragmentation that afford the neutral complexes Pt(dppb), Pt(CO)(dppa), and Pt(CO)(PPh)(C≡CPPh)(dppa). The oxidation of [Pt(CO)(dppm)] results in its oligomerization to yield the larger heteroleptic Chini-type clusters [Pt(CO)(dppm)], [Pt(CO)(dppm)], and [Pt(CO)(dppm)] (for the latter there is only IR spectroscopic evidence). All the clusters were characterized by means of IR and P NMR spectroscopies and electrospray ionization mass spectrometry. Moreover, the crystal structures of [NEt][Pt(CO)(dppm)]·CHCN, [NEt][Pt(CO)(dppm)]·2CHCN·2dmf, [NEt][Pt(CO)(dppm)]·4dmf, [NEt][Pt(CO)(dppf)]·2CHCN, Pt(CO)(dppa)·0.5CHCN, Pt(CO)(PPh)(C≡CPPh)(dppa)·2thf, and Pt(dppb) were determined by single-crystal diffraction (dmf = dimethylformamide; thf = tetrahydrofuran).