Open-Shell Organometallics as a Bridge between Werner-Type and Low-Valent Organometallic Complexes. The Effect of the Spin State on the Stability, Reactivity, and Structure.

http://depa.fquim.unam.mx/amyd//archivero/ML2_26285.pdf

Stable two-coordinate, open-shell (d1-d9) transition metal complexes.

Thermochemical studies of organo-transition metal carbonyls and related compounds

Aggregates. 2. Syntheses and Reactivities of Homo/HeteroMAAs Florence Mongin* and Anne Harrison-Marchand* Equipe Chimie et Photonique Mol eculaires, Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS-Universit e de Rennes 1, Bât. 10A, Case 1003, Campus de Beaulieu, Avenue du G en eral Leclerc, 35042 Rennes C edex, France Laboratoire COBRA de l0Universit e de Rouen, INSA de Rouen, CNRS, UMR 6014 & FR 3038, IRCOF, Rue Tesni ere, 76821 Mont St Aignan C edex, France

Mixed AggregAte (MAA): a single concept for all dipolar organometallic aggregates. 2. Syntheses and reactivities of homo/heteroMAAs.

Some highlights from the development and use of bulky monodentate ligands

The interaction of manganese(U) chloride with Grignard or dialkylmagnesium reagents derived from Me3CCH2Cl. Me2PhCCH2Cl, and Me3SiCH2Cl yields thermally stable dialkyl compounds of manganese(II). For the neophyl compound. Mn2(CH2CMe2Ph)π. a dimeric structure with a bridging alkyl group, the phenyl group of which lies over a manganese atom, has been confirmed by X-ray diffraction (to be reported separately). For the trimethylsilyl-methyl compound, {Mn(CH2SiMe3)2}n, tetrahedral co-ordination of MnII is achieved by polymerisation via alkyl bridges (cf. BeMe2).The dialkyl compounds interact with Lewis bases such as NNN′N′-tetramethylethylenediamine to give mono-meric complexes of the type MnR2·tmed and with lithium alkyls to give solvated dilithium tetra-alkylmanganate(II) complexes Li2[MnR4]. Salts where R = Me are also described and the existence of dimethyl- and dlphenyl-manganese is questioned.The e.s.r. spectra of the manganese(II) species are described and assignments made. Oxidation of the dialkyl compounds in the presence of an excess of alkylating agent gives green solutions whose e.s.r. spectra are similar to that of tetranorbornylmanganese(IV) so that the solutions presumably contain unstable manganese(IV) alkyls.

Neopentyl, neophyl, and trimethylsilylmethyl compounds of manganese. Manganese(II) dialkyls; manganese(II) dialkyl amine adducts; tetra-alkylmanganate(II) ions and lithium salts; manganese(IV) tetra-alkyls

Trimethylsilylmethyl and methyl compounds of manganese, cobalt and uranium

The interaction of trichlorotris(tetrahydrofuran)molybdenum(III), MoCl3(C4H8O)3, with trimethylphosphine in ether or tetrahydrofuran gives trichlorotris(trimethylphosphine)molybdenum(III). This has been shown to react with sodium borohydride to yield MoH(BH4)(PMe3)4, whose structure has been determined by X-ray crystallography. The compound crystallizes in the orthorhombic space group Cmcm with a= 12.572(5), b= 12.405(5), c= 14.433(6)A, and Z= 4 for Dc= 1.23 g cm–3. The final R factor was 0.048 based on 1 078 independent observed reflections. In the crystal the molecules lies at the intersection of two mirror planes, with the hydride, the molybdenum atom, and the boron atom of the bidentate BH4 group lying precisely on the intersection. Hydrogen-1 and 31P n.m.r. spectra for the complex are also briefly reported.

Synthesis and crystal structure of hydrido(tetrahydroborato)tetrakis(trimethylphosphine)molybdenum(II)

The crystal structure of MoMe2(η6-C6H5)(PPhMe2)2 and MoMe2(η6-C6H5Me)(PPhMe2)2 have been determined from three-dimensional X-ray diffraction data collected by counter methods The former crystallizes in the monoclinic space group P21/n with a= 8108(4), b= 24287(8), c= 11961(5)A, β= 9659(4)°, and Z= 4 for Dc= 136 g cm–3 The final R value was 0035 based on 1 271 independent observed reflections MoMe2(η6-C6H5Me)(PPhMe2)2 crystallizes in the triclinic space group P with a= 9128(2), b= 9611 (2), c= 14842(3)A, α= 10544(3), β= 9372(3), γ= 10247(3)°, and Z= 2 for Dc= 135 g cm–3 The R value was 0·019 for 3 586 observed reflections The presence of the methyl group on the toluene ligand does not appreciably alter the electronic environment of the molybdenum atom In the toluene derivative the two Mo–C(σ) bonds average 2291 (5)A The Mo–C(σ) lengths range from 2250(2) to 2344(2)A, and are seen to vary in a pair-wise fashion such that the arene shows a tendency to act as a diene

The crystal structures of MoMe2(η6-C6H6)(PPhMe2)2 and MoMe2(η6-C6H5Me)(PPhMe2)2

Treatment of trichlorotris(tetrahydrofuran)molybdenum, MoCl3(C4H8O)3, with tertiary phosphines under certain conditions gives MoCl3(PR3)(C4H8O)2(PR3= PMe3 or PMe2Ph) which on alkylation with dimethylmagnesium in the presence of arenes yield the 18-electron methyl–arene complexes Mo(CH3)2(η6-Ar)(PR3)2(Ar = benzene, toluene, or o- and p-xylene). The reaction in tetrahydrofuran affords the known dimers Mo2(CH3)4(PR3)4. Action of CO on the benzene complex at 1 atm gives Mo(CH3)2(η6-C6H6)(CO)(PR3) which when set aside under N2 yields Mo(η6-C6H6)(PMe2Ph)3 possibly via the acetone complex Mo(Me2CO)(η6-C6H6)(PMe2Ph). Reaction of MoCl3(PR3)(C4H8O)2 with Me2Mg and cyclo-octa-1,5-diene (cod) affords Mo(CH3)2(cod)(PR3)2 in low yields. The new compounds have been characterised by i.r. and 1H, 13C, and 31P n.m.r. spectroscopy.

Ernesto Carmona-Guzman

Papers

Neopentyl, neophyl, and trimethylsilylmethyl compounds of manganese. Manganese(II) dialkyls; manganese(II) dialkyl amine adducts; tetra-alkylmanganate(II) ions and lithium salts; manganese(IV) tetra-alkyls

Trimethylsilylmethyl and methyl compounds of manganese, cobalt and uranium

Synthesis and crystal structure of hydrido(tetrahydroborato)tetrakis(trimethylphosphine)molybdenum(II)

The crystal structures of MoMe2(η6-C6H6)(PPhMe2)2 and MoMe2(η6-C6H5Me)(PPhMe2)2

Alkyl-arene and -cyclo-octadiene complexes of molybdenum(II) containing tertiary phosphines