Synthesis and structure of alkynylplatinum(IV) complexes containing the pincer group [2,6-(dimethylaminomethyl)phenyl-N,C,N]-

An alkynyliodine(III) reagent IPh(CCSiMe 3)(O 3SCF 3) reacts readily with Pt(O 2CAr)(NCN) to give Pt(O 2CAr)(O 3SCF 3)(CCSiMe 3)(NCN), and addition of sodium iodide gives isolable Pt(O 2CAr)I(CCSiMe 3)(NCN) as the first examples of alkynylplatinum(IV) 'pincer' complexes. Reaction of phenyl(trimethylsilylalkynyl)iodine(III) triflate with Pt II(O 2CAr)(NCN) (Ar = Ph, 4-trifluoromethylphenyl (Ar F); NCN = [C 6H 3(CH 2NMe 2) 2-2,6]) at ambient temperature gives solutions of Pt IV(O 2CAr)(OTf)(C≡CSiMe 3)(NCN) [Ar = Ph (1a); Ar = Ar F (1b)]. Addition of sodium iodide (NaI) to 1 results in the isolation of Pt IV(O 2CAr)I(C≡CSiMe 3)(NCN) [Ar = Ph (2a); Ar = Ar F (2b)] in >90% yields. In these first examples of alkynyl(pincer)platinum(IV) complexes, the pincer group is present as a mer-[NCN] - tridentate donor and the alkynyl group is located cis to the pincer carbon donor, and the triflate (1a, 1b) and iodide groups (2a, 2b) are located trans to the pincer carbon; an X-ray structural analysis has been completed for 2b. © 2004 Elsevier B.V. All rights reserved.