Synthetic Routes to Transition‐Metal‐Substituted Pentadiynylidene Complexes

Abstract

Sequential reaction of the dimethylamino(ethynyl)carbene complex [(CO)5 WC(NMe2)CCH] (1) with nBuLi, CuI and BrCCSiMe3 affords the dimethylamino(trimethylsilylbutadiynyl)carbene [(CO)5WC(NMe2)CCCCSiMe3] (2). Desilylation of 2 with KF/THF/MeOH gives [(CO)5WC(NMe2)CCCCH] (3). The C‐stannylated carbene complex [(CO)5WC(NMe2)CCCCSnBu3] (4) is obtained by deprotonation of 3 with nBuLi and subsequent reaction with Bu3SnCl. Pd‐catalyzed coupling of complex 4 with [ClRu(CO),Cp] affords the heterobimetallic pentadiynylidene complex [(CO)5WC(NMe,)CCCCRu‐(CO)2Cp] (5) The analogous Fe derivative [(CO),WC(NMe,)CCCCFe(CO)2Cp] (6) is obtained by sequential reaction of 3 with nBuLi and [IFe(CO)2Cp] Similarly, treatment of 3 first with nBuLi and then with half an equivalent of HgCl2 affords the novel C4HgC4‐bridged biscarbene complex [(CO)3WC(NMe2)CCCCHgCCCCC(NMe2)W(CO)5]( 7 ) All new compounds are stable at room temperature. Spectroscopic data suggest weak interaction of the metal centers in 5 – 7.

Polynuclear Complexes with Propynylidene C3-Bridges: General Synthetic Route to Bis-, Tris-, and Tetrakis(ethynylcarbene) Complexes

“…upfield shift of the C(carbene) resonance. A similar trend is observed for the tris-and tetrakis(ethynylcarbene) comThe 1 H-and 13 C-NMR spectra of complexes 8a, b exhibit only one singlet for the cyclopentadienyl rings implying that plexes 11a, 12a, and 13Ϫ15.…”

“…The resonance of the carbene carbon atom in the 13 C-NMR spectra of the complexes 2Ϫ15 is at rather high field 12a, and 13Ϫ15.…”

“…Previously, we reported on the efficient preparation of Polynuclear transition metal complexes with π-conjubimetallic ethynylcarbene complexes by nucleophilic substigated carbon bridges have recently attracted considerable tution of a lithiated ethynyl-or butadiynylcarbene complex interest due to their potentially useful chemical and physical for the halide X in metal monohalides [XMЈ(LЈ m )] [13] [15] . In properties.…”

“…sandwich complexes can be considered as building blocks in the synthesis of linear [3] , star-shaped [6] [7] , biphenyl [8] , binaphthyl [7] , an-dimethylamino(trimethylsilylethynyl)carbene complexes [(CO) 5 MϭC(NMe 2 )CϵCSiMe 3 ] (M ϭ W, Cr) proved to be thracene [9] , 1,6-methano[10]annulene-2,7-diyl [10] , alkenyl, [11] or ammonium pentadienide [12] bridges are readily suitable precursors for the L n MC 3 fragment. Desilylation with KF/THF/MeOH [15] , followed by deprotonation with accessible. By contrast, apart from our results on the synthesis of the C 4 HgC 4 -bridged complex [(CO) 5 Wϭ nBuLi, gave the lithiated acetylide [(CO) 5 MϭC(NMe 2 )-CϵCLi] (M ϭ W, Cr).…”

“…By contrast, apart from our results on the synthesis of the C 4 HgC 4 -bridged complex [(CO) 5 Wϭ nBuLi, gave the lithiated acetylide [(CO) 5 MϭC(NMe 2 )-CϵCLi] (M ϭ W, Cr). Treatment of two equivalents of this C(NMe 2 )CϵCCϵCHgCϵCCϵCC(NMe 2 )ϭW(CO) 5 ] [13] , examples of π-conjugated metal-bridged trinuclear biscar-tungstate (or chromate) in situ with one equivalent of the metal dichloride [Cl 2 M(PEt 3 ) 2 ] (M ϭ Ni, Pd, Pt) resulted bene complexes are unknown [14] . Nevertheless, all these sys-…”