Synthesis of triynylcarbene complexes and of bi- and trinuclear complexes with heptatriynylidene C7-bridges

The dimethylamino (trimethylsilylhexatriynyl)carbene complex [(CO)(5)W=CO(NMe2)C=CC=CC=CSiMe3] (2) was synthesized by two different routes: (a) by sequential reaction of the ethynylcarbene complex [(CO)(5)W=C(NMe2)C=CH] with nBuLi, CuI, and IC=CC=CSiMe3 and (b) by Cl2Pd(MeCN)(2)-catalyzed coupling of [(CO)(5)W=C(NMe2)C=CSnn Bu-3] with IC=CC=CSiMe3. Desilylation of 2 with KF/THF/MeOH afforded the hexatriynylcarbene complex [(CO)(5)W=C(NMe2)C=CC=CC=CH] (4). Deprotonation and coupling with ClSnn Bu-3, gave the C-stannylated carbene complex [(CO)(5)W-C(NMe2)C=CC=CC=CSnn Bu-3] (5). Reaction of 5 with nBuLi and [ClRu(CO)(2)Cp] afforded the heterobimetallic heptatriynylidene-bridged complex [(CO)(5)W=C(NMe2)C= CC=CC=CRu(CO)(2)Cp] (6). The trinuclear complex [(CO)(5)W=C(NMe2)C=CC=CC=C-Hg-C=CC=CC=C(Me2N)C=W(CO)(5)] (7) was obtained by reaction of 4 with nBuLi and HgCl2. All new compounds are stable at room temperature. Spectroscopic data suggest weak interaction of the metal centers in 6 and 7. (C) 1999 Elsevier Science S.A. All rights reserved.