Abstrakt
The bimetalladodecaborane cluster compound [(PMe2Ph)(4)Pt2B10H10] 1, quantitatively reacts with EtNC at room temperature to afford [{(EtNC)(PMe2Ph)(3)}(mu-EtNC) Pt2B10H10] 3 in which one molecule of EtNC replaces a terminal PMe2Ph ligand, and a second molecule of EtNC bridges the PtePt vector. The metalbridging EtNC molecule can be ejected from 3, either by irradiation with UV light, or via displacement with CO to form [{(EtNC)(PMe2Ph)(3)}(mu-CO) Pt2B10H10] 4.
The CO-bridge may then in turn be replaced with SO2 to give [{(EtNC)(PMe2Ph)(3)}(mu-SO2) Pt2B10H10] 5. If 3 is allowed to react directly with SO2 then the SO2 molecule takes up a bridging position and the bridging EtNC displaces a terminal metal-bound phosphine to afford [{(EtNC)(2)(PMe2Ph)(2)}(mu-SO2) Pt2B10H10] 6.
The transient absorption spectrum of 3 under UV illumination is investigated and shows that the bridging isonitrile is ejected to produce a transient spectrum very similar to that of [(PMe2Ph)(4)Pt2B10H10] 1. Reaction of [(PMe2Ph)(4)Pd2B10H10] 7, viz. the dipalladium analogue of 1, with EtNC results in the displacement of two PMe2Ph phosphine ligands forming [{(EtNC)(2)(PMe2Ph)(2)} Pd2B10H10] 8, which has no bridging EtNC unit and which shows only a weak ability to form an adduct with SO2.
DFT calculations at the B3LYP/6-31G* level mirror the observed data well. (C) 2013 Elsevier B. V.
All rights reserved.