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^文提要: Complexes Os3(CO)10(CNR)(NCMe) (R = Pr, Pri, CH2Ph)
reacted with dimethyl acetylenedicarboxylate to give Os3(CO)9(
μ3-η2-CNR)(μ3-η3-C(O) C(CO2Me) C(CO2Me) (31a, R = Pr; 31b, R
= Pri; 31c, R = CH2Ph) and Os2(CO)6(μ-η2-η3-C(OH)C(CO2Me)(CO2
Me)) (32a, R = Pr; 32b, R = Pri; 32c, R = CH2Ph). The relative
yields of the products (31:32) depended upon the nature of the
alkyl groups of isocyanide. The three Os atoms in 31 are
asymmetrically bridged by μ3-η3-C(O)C(CO2Me)C(CO2Me) moiety
and an unusual μ3-η2 isocyanide ligand. Its formation
involved the C-C bond formation between an alkyne and a CO
ligand. In complex 32, two kinds of C-C bond formations,
including coupling of alkyne and CO as well as coupling of
alkyne and CNR were observed. The structures of 31 and 32 were
characterized by single crystal X-ray diffraction analyses.
Reaction of the hydridotriosmium cluster (μ-H)2Os3(CO)10 with
CNNPPh3 afforded Os3(CO)10(μ-η-CHNNPPh3) (33) and Os3(CO)10(
μ-CHPPh3) (34). Complex 33 was the intermediate of the
reaction and it transformed slowly to form 34 by loss of a
dinitrogen molecule. The kinetic behavior of this
transformation has been examined by 1H NMR study. The Ea, ΔG*,
ΔH*, andΔS* are 28.09 Kcal/mol, 24.7 Kcal./mol, 27.45 Kcal/
mol, and 8.93 cal/mol.K, respectively. Theromlysis of 34
in refluxing toluene gave a colorless compound (μ-H)3Os3(CO)9(
μ3-CCO2CH2Ph) (35), which contains a ligand capped on the face
of the trianglo-osmium cluster, and this capping ligand contains
a CH2Ph moiety, which is likely to be derived from toluene. The
structure of 35 was characterized by single crystal X-ray
diffraction analysis. Reaction of Ru3(CO)10(NCMe)2 (1) with
methyl propiolate afforded a red compound Ru3(CO)9(μ-CO)(μ3-
η2-CH=CCO2Me) (36) and a yellow compound Ru2(CO)6(μ-η2-η4-(
HC=CCO2Me)2) (37). Reaction of Ru3(CO)11(CNPr) with
diphenylacetylene gave a red complex Ru3(CO)5(μ-CO)2(CNPr)(μ3-
η4-CPhCPhCPhCPh) (38). The structures of 37 and 38 were
characterized by single crystal X-ray diffraction analyses.
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