Ruthenium isocyanides

Until the appearance of a recent communication 37), no zero-valent ruthenium isocyanide complexes had been described. The synthesis of these complexes was accomplished by a lengthy reaction sequence, which was necessary since simple reactions such as substitution of a ligand in... 

Bis(phoshacyclopentadienyl)titanium(II) complexes, preparation and reactivity, 4, 265 Bisphosphanes on DIOP modification, 10, 7 in hydrogenations, 10, 7 in hydrogenations, P-chiral ligands, 10, 11 Bisphosphinidenes, with platinum(II), 8, 453 -54 Bisphosphinites, in hydrogenations, 10, 14 Bis(phosphinoalkyl-thioether)arenes, in ruthenium isocyanides, 7, 138... 

Isocyanides may be coordinated to the central iron or ruthenium atom in the corresponding 2,3-naphthalocyanines, e.g. 7. 

Novel ruthenium-amidinate complexes of the type (j -CgHsRlRufamidina-te)X (R = Me, OMe, F X = Cl, Br, OTf) and [Ru(amidinate)(MeCN)4][PF6] have been synthesized by photochemical displacement of the benzene ligand in (j -CgHglRufamidinatelX by substituted arenes or MeCN. The acetonitrile ligands of [Ru(amidinate)(MeCN)4][PF6] are easily replaceable by other cr-donor ligands (L) such as pyridines, phosphines, and isocyanides to afford the corresponding derivatives [Ru(amidinate)(MeCN) (L)4 ][PF6] n — 1, 2). These reactions are summarized in Scheme 142. ... 

Rearrangement of the ruthenium (diaminocarbene) isocyanide complex 28 has been noted above. Migration of the carbene substituent group is thought to occur via an intramolecular cyclization reaction (57,58) ... 

Indoles were synthesized by the intramolecular functionalization of a benzylic C-H bond. Hence, the reaction of 2,6-xylyl isocyanide with a ruthenium complex led to 7-methylindole (Equation (36)). 

This transformation proceeds through coordination of the isocyanide group to the ruthenium complex (structure 172), followed by insertion of the C-bound ruthenium into the benzylic C-H bond (intermediate 173). After ruthenium-mediated addition of the benzylic carbon to the isonitrile carbon and tautomerization, the desired product was obtained via elimination of the ruthenium complex. 

Ruthenium-(O) and -(i).—Apart from the ruthenium clusters discussed separately, only a few new ruthenium(O) complexes have been reported. The isocyanide complexes [Ru(CO)2(CNRKPPh3)2] and [Ru(CO)(CNR)(PPh3)3] have been prepared as shown in Scheme 1. Use of oxygen in the final step gave... 

TRI- AND TETRANUCLEAR CARBONYL-RUTHENIUM CLUSTER COMPLEXES CONTAINING ISOCYANIDE, TERTIARY PHOSPHINE, AND PHOSPHITE LIGANDS. RADICAL ION-INITIATED SUBSTITUTION OF METAL CLUSTER CARBONYL COMPLEXES UNDER MILD CONDITIONS... 

C2H,N, Pyridine, 3,5-dimethyl-palladium complex, 26 210 CbHsNO, Benzoyl isocyanide chromium com-C HbO, Ethanone, 1-phenyl-manganese complex, 26 156-158 CBH, 02, Methyl benzoate chromium complex, 26 32 C H i, o-Xylylene magnesium complex, 26 147 ChH P, Phosphine, dimethylphenyl-iron complex, 26 61 ruthenium complex, 26 273 ChH12, 1,5-Cyclooctadiene iridium complex, 26 122 ruthenium complexes, 26 69-72, 253-256 ChH OjPS, 2-Butenedioic acid, 2-(dimethylphosphinothioyl)-dimethyl ester, manganese complex, 26 163... 

Some interesting chemistry has appeared relating to the ability of the isocyanide ligand to stabilize unusual oxidation states. A series of palladium metal - metal bonded complexes has been synthesized by redox reactions involving two metal complexes in different formal oxidation states (33 -35). Similar ruthenium(I) and osmium(I) dimers have been prepared by an unusual homolytic fission of a ruthenium-carbon bond (36) or by singleelectron oxidation of Os(CNXylyl)5 (18). 

Reactions of isocyanides with metal-metal multiple-bonded dimers of molybdenum, rhenium, ruthenium, and rhodium have effected cleavage of... 

Os6(CO)l8(CNC6H4Me-p)2 (62) have shown the former to have the same Os6 bicapped tetrahedron of the parent compound Os6(CO) g, whereas the latter has a rearranged metal skeleton with one isocyanide bridging three osmium atoms (40). With the ruthenium product Rus(CO),4(CNBu )2 (63), isolated... 

New Photosensitizers Isocyanide Bipyridine Mixed-ligand Ruthenium(II) complexes. 

Another type of unique coupling reaction was reported by Jones and coworkers [87]. The low-valent ruthenium phosphine complexRuH2(dmpe)2 catalyzed intramolecular insertion of isocyanide into the benzyl C-H bond of 2,6-xy-lylisonitrile under thermal conditions (Eq. 59). Their finding provided a new route to the synthesis of indoles. 

The electron-rich ruthenium center can render the bound X ligand nucleophilic as has been demonstrated by the reactions of (rj5-C5H5)-(PPh3)2Ru—C=N (30) with a variety of electrophiles. Baird and Davies have shown, for example, that addition of alkyl halides to 30 gives the corresponding isocyanides in moderate yield [Eq. (32)] (29). Other... 

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