V. A. Maksakov

The rearrangement of the uncoordinated allyl fragment of the carboxamide ligand in (η-H) Os3(CO)10(η-OCNHCH2CHCH2) cluster

Abstract The rearrangement of the uncoordinated allyl fragment of the complex carboxamide ligand in (η-H)Os 3 (CO) 10 (η-OCNHCH 2 CHCH 2 ) (1) at room temperature has been observed. A migration of the terminal double bond to the α-position in 1 leads to the formation of four novel isomeric clusters (η-H)Os 3 (CO) 10 (η-OCNHCHCHCH 3 ) ( 2a-d ). Based on IR and 1 H NMR data, a conclusion has been made that the formation of isomers is attributed to the rotation of the ligand about the CC and NC(O) bonds.

Syntheses and crystal structure of bridged Os3-clusters with chiral 3-carane-type ligands

Abstract Reaction of (μ-H)2Os3(CO)10 cluster with (1S,3S,6R)-3-dimethylaminocarane-4-one E-oxime results in loss of dimethylamino group and formation of (μ-H)Os3(CO)10(μ-ONC) cluster (43%). Treatment of cluster Os3(CO)11(NCCH3) with (1S,3S,6R)-3-mercaptocaran-4-one E-oxime gives cluster (μ-H)Os3(CO)10(μ-S⋯) in 86%, whose structure was proved by X-ray single crystal analysis. Decarbonylation of the later compound with (CH3)3NO leads to a diastereomeric mixture of (μ-H)Os3(CO)9(μ,η2-(S,N)⋯) clusters in 64% yield.

Syntheses and characterization of OsPt2(μ-CO)(μ-I)2(CO)2(PPh3)3 and Os2(μ-I)2(CO)6−n(PPh3)n (n = 1, 2) in the solid-state and solution

Abstract The reaction of Os2(CO)6(μ-I)2 with Pt(dba)(PPh3)2 or Pt(PhCCPh)(PPh3)2 affords three novel complexes Os2(CO)6−n(μ-I)2(PPh3)n [n = 1 (2), n = 2 (4)] and OsPt2(CO)2(μ-CO)(μ-I)2(PPh3)3 (3). 2 and 3 were characterized by X-ray analysis. The isotopically pure 187Os2(CO)6(μ-I)2 was also used in the synthesis of the corresponding complexes 2′–4′ to study their structures in solution. It was determined that the OsPt2(CO)2(μ-CO)(μ-I)2(PPh3)3 cluster is symmetric in solution whereas in the solid-state it has an asymmetric structure which may be explained by the different disposition of the μ-I ligands around the OsPt2-triangle. 1J(Os-Os), 2J(Os-P), 1J(Pt-Pt), 1J(Pt-P), and 2J(P-P) coupling constants have been determined.

Hydroxylamines as new decarbonylating reagents in the synthesis of metal carbonyl derivatives

Abstract Mononuclear and cluster carbonyl complexes react with amino functional compounds under mild conditions in the presence of H2O2 to form mixed amino carbonyl derivatives. It was found that a group of reactive species facilitating the process are hydroxylamines which arise in situ as a result of oxidation of amino compounds. On the basis of kinetic data and certain other measurements the mechanism of interaction of M(CO)6 (M = Cr, Mo, W) and NH2OH is proposed. This includes nucleophilic attack by NH2OH on a carbonyl carbon resulting in CO oxidation and CO2 elimination with simultaneous intramolecular movement of the amino group to the metal atom. The above mechanism is compared with that for the analogous reaction facilitated by Me3NO, studied earlier.

Synthesis of trinuclear mixed-metal clusters Os2Fe(CO)10L2(L = OH, I, CO). The crystal structures of Os2Fe(CO)10(μ-OH)2 and Os2Fe(CO)12 · 0.41Os3(CO)12

Abstract The heterometallic clusters Os2Fe(CO)10(μ-X)2 (X = OH, I) were obtained from the binuclear osmium complexes Os2(CO)6Xn(X = Cl, n = 4; X = I, n = 2). The structure of Os2Fe(CO)10(μ-OH)2 was determined by a single-crystal X-ray diffraction analysis. The crystal is triclinic and crystallizes in the space group Pl¯ and a = 14.009(6), b = 13.330(4), c = 9.511(2)A, α = 103.69(2), β = 81.83(3), γ = 102.22(3)°, V = 1699(1) A3, Z = 4, Dcalc = 2.969g cm−3, R = 0.093 for 2359 independent reflections (Fo > 6σ (Fo)). The cluster consists of an open triangular OsFeOs metal core with no Os-Os bond. The bridging OH groups are coordinated semiaxially and span the Os-Os edge. On heating in the presence of an excess of Fe2(CO)9, the Os2Fe(CO)10(μ-I)2 cluster is converted to Os2Fe(CO)12. The co-crystallate Os2Fe(CO)12 · 0.41Os3(CO)12 was isolated from the solution of Os2Fe(CO)10(μ-I)2, as the product of decomposition of the initial cluster. It crystallizes in the monoclinic system, space group P21/n, with a = 8.056(2), b = 14.743(2), c = 14.520(2)A, β = 100.62(1)°, V = 1695.0(5)A3, Z = 4, Dcalc = 3.179g cm−3 and R = 0.0250 for 1997 independent reflections (Fo > 4σ(Fo)).

Stereospecific coordination ofl-hydroxyproline esters with triosmium clusters

AbstractThe reactions of cluster (μ-H)Os3(CO)10(μ-OH) with ethyl and isopropyl esters ofl-oxyproline were studied. In the presence of Me3NO intermediate complex (μ-H)Os3(CO)9(μ-OH)L (L — isopropyl ester ofl-oxyproline) is formed, which slowly converts to the more stable cluster (μ-H)Os3(CO)9

Synthesis of optically active hydridocarbonyl triosmium clusters with terpene derivatives as ligands. Molecular structure and absolute configuration of a cluster with a bridging dihydroimidazole ligand

\left\{ {\mu ,\eta ^2 } \right.--{\rm O}|\overline {CHCH_2 CH(COOPr^i )NH} \mathop C\limits^| \left. {H_2 } \right\}

PREPARATION AND REACTIVITY OF METAL CONTAINING MONOMERS. XLIII: SYNTHESIS AND PROPERTIES OF COPOLYMERS OF STYRENE OR ACRYLONITRILE WITH TRIOSMIUM CARB ONYL CLUSTER MONOMERS

. Cluster complexes containing chelate-bridging heterocycles were also obtained by heating (μ-H)Os3(CO)10(μ-OH) with esters ofl-oxyproline. In both cases, only one of the possible diastereomeric complexes (μ-H)Os3(CO)9