Chemistry of di- and tri-metal complexes with bridging carbene or carbyne ligands. Part 15. Reactions of the complex [W(CR)(CO)₂(η-C₅H₅)](R = C₆H₄Me-4) with iron carbonyls; crystal structures of [Fe₂W(µ₃-CR)(µ-CO)(CO)₈(η-C₅H₅)] and [FeW₂(µ₃-RC₂R)(CO)₅L(η-C₅H₅)₂](L = CO or O)

Abstract

Chemistry ofCarbyne Ligai [W( X R ) ( CO) Structures of [FeW,(P3-RC* Diand Tri-metal Complexes with Bridging Carbene or nds. Part 15.' Reactions of the Complex 2(q-C5H5)] (R = CsH4Me-4) with Iron Carbonyls; Crystal [ Fe2W( W C R ) (P-CO) (C0)8(vC5 H 5) I and R)(C0)5L(q-C5H5)2] (L = CO or 0 ) "

Chemistry of highly electrophilic binuclear cations. 6. Synthesis of the alkyne-bridged complexes [Mo2(η5-C5H5)2{μ-η2:η2-HC2(p-tol)}(CO)2(μ-L2)][B{3,5-C6H3(CF3)2}4]2 and their isocyanide derivatives (L2=Ph2PCH2PPh2, Me2PCH2PMe2)

“…In agreement with this, the CH resonance of the bridging alkyne ligand now appears considerably more shielded (d = 5.54 ppm), but here the couplings to the phosphorus atoms are quite different (J HP = 15, 4 Hz), suggesting a more asymmetric coordination of the alkyne ligand to the dimetal centre, which perhaps would compensate for the distinct number of isocyanide ligands bonded to the molybdenum atoms. There are many possibilities for asymmetric binding of an alkyne ligand to a dimetal centre [10,[14][15][16], Chart 3. and our spectroscopic data do not allow us to fully identify the actual coordination mode of the alkyne bridge in 6. Thus, the structural diagram depicted in Chart 3 must be considered only as an oversimplified representation of this unstable cation.…”

Delocalized bonding in tetrahedral organo-transition metal clusters: an EHMO study of metal vertex rotations in Co2Fe(CO)9S, CpMoCo2(CO)8CR, and in Cp2Mo2(CO)4(RC≡CR)

“…There is an example of a molecule -the (C,H,)WFe,(CO),C-tolyl cluster 15 -in which the vertex is rotated through 90°, but the two Fe(C0)3 units are linked by a bridging carbonyl (22). This molecule would be an interesting candidate for a detailed variable-temperature NMR study.…”

“…6. Finally, we were aware of the structure of the (C5H5)WFe,(CO)9C-tolyl cluster 15 in which the tungsten-to-cyclopentadienyl vector is almost exactly in the plane of the metals, as in 3c (22). The crucial parameter to note here is the angle made by the Cp,,,,,,,-metal axis with a line joining this metal to the centre of the cobalt-cobalt (or iron-iron) vector.…”

Unusual Reactions of Cationic Bridging Carbyne Complexes of Dimethylsilane-Bridged Bis(η5-cyclopentadienyl)diiron Tricarbonyl with Nucleophiles. A Route to Iron−Sulfur Cluster Bridging Carbene Complexes

“…In recent years, our interest in developing the methodologies of the synthesis of transition metal bridging carbene and carbyne complexes stems from the fact that many such complexes are themselves metal clusters or are the precursors of metal cluster complexes, which have played important roles in many catalytic reactions. , A considerable number of di- or trimetal bridging carbene and bridging carbyne complexes have been synthesized by Stone and co-workers − and by us. , Most recently, we found a new method for the preparation of dimetal bridging carbene and carbyne complexes: the reactions of highly electrophilic diiron cationic carbyne complexes [Fe 2 (μ-CO)(μ-CAr)(CO) 2 (η 5 -C 5 H 5 ) 2 ]BBr 4 (Ar = C 6 H 5 , p-CH 3 C 6 H 4 ) with nucleophiles to give a series of diiron bridging carbene complexes. , This offers a new and useful method for the preparation and structural modification of dimetal bridging carbene complexes.…”