Di- and Polymetallic Heteroatom Stabilized (Fischer) Metal Carbene Complexes

Recent advances in the field of multicarbene and multimetal carbene complexes of the Fischer-type

“…A comprehensive review by Sierra in 2000 accounts for most of the results before 1999 [11]. The first section will deal especially with dinuclear biscarbene complexes and methods to prepare such compounds, whereas the following section covers the area of Fischer carbene complexes containing metal-fragments as carbene substituents.…”

“…The reaction of dilithiated substrates with two equivalents of a metal carbonyl and reaction with alkylating reagents has led to the formation of bimetallic biscarbene complexes [11]. The spacer unit may be a π-conjugated substrate in which case the terminal metal fragments will be in electronic contact with each other via the carbene moiety and through the spacer unit.…”

“…Fischer carbene anions were reacted with a large variety of metal carbonyl cations as electrophiles. One equivalent of a carbon bidentate electrophile afforded dinuclear monocarbene complexes, whereas half an equivalent gave dinuclear biscarbene complexes 31 (Scheme 7) [11]. followed by an oxidation of the dianion with AgBF 4 generated the a,a'-unsaturated biscarbene complex [{Cr(CO) 5 } 2 {μ-C(OMe)CH=CHC(OMe)] 37 [80].…”

“…The reactivity of Fischer carbene complexes containing α,β-unsaturated carbon substituents with a variety of organic substrates have been thoroughly investigated and extensively reviewed [1][2][3][4][5][6][7][8][9][10][11][84][85][86][87]. Well-known classes of monocarbene complexes used as precursors in organic synthesis via organometallic intermediates are those displaying carbene substituents with a-unsaturated carbon-carbon bonds.…”

“…In ongoing work, the lithiation of the β-carbon of dimethylamino(1-ethynyl)carbene of tungsten pentacarbonyl can be reacted with iodine and tris(n-butyl)stannylchloride to give iodoethynylcarbene and the stannylated ethynylcarbene complexes, respectively. These two ethynylcarbene complexes react in a carbon-carbon coupling reaction catalyzed by [Pd(CNMe) 2 Cl 2 ]to give a biscarbene with a C 4 -, C 8 -and C 12 -spacer linking the two carbene carbon atoms [11].…”