Oxidation of Diphosphazane-bridged Derivatives of Diruthenium Nonacarbonyl by Silver(I) Salts in Protic Solvents: Synthesis, Structural Characterization and Protonation of the Adduct 2-OC(O)>(CO)42> (R = Me or Pri) involving a Novel Mode of Co-ordin...
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Source and publish data:
Journal of the Chemical Society, Dalton Transactions p. 2735 - 2748 (1993)
Update date:2022-08-04
Topics:
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Authors:
Field, John S.
Haines, Raymond J.
Sundermeyer, Joerg
Woollam, Stephen F.
Article abstract of DOI:10.1039/DT9930002735
Treatment of 2> (R = Me or Pri) with AgSbF6 in methanol, ethanol or tetrahydrofuran-water resulted in the formation of the solvento species 2>2 which is isolable for R' = H but which spontaneously deprotonates to the alkoxycarbonyl-bridged derivative 2-OC(OR')>(CO)4<μ-(RO)2PN(Et)P(OR)2>2>SbF6 for R' = Me or Et.The aqua species 2>2 was readily deprotonated in consecutive steps by appropriate bases to afford respectively the hydroxycarbonyl-bridged species 2-OC(OH)>(CO)4<μ-(RO)2PN(Et)P(OR)2>2>SbF6 and the adduct 2-OC(O)>(CO)4<μ-(RO)2PN(Et)P(OR)2>2> in which the carbon dioxide molecule adopts a novel bridging co-ordination mode; this deprotonation is reversible and treatment of the latter with HBF4*OEt2 leads to stepwise regeneration of the aqua species.The co-ordinated water molecule in iO)2PN(Et)P(OPri)2>2>2 was readily displaced by acids HA derived from conjugate bases with potential co-ordinating properties such as thiolate ions R''S(1-) (R'' = H or Ph) or carboxylate ions R'''CO2(1-) (R''' = H, Me, Ph or CF3), to produce monocationic pentacarbonyl species of the type iO)2PN(Et)P(OPri)2>2>SbF6; detection of an intermediate, presumably iO)2PN(Et)P(OPri)2>2>2, was possible for HA = HCO2H and MeCO2H.The sulfido derivatives iO)2PN(Et)P(OPri)2>2>SbF6 (R'' = H or Ph) rapidly decarbonylate in solution to afford the tetracarbonyl products iO)2PN(Et)P(OPri)2>2>SbF6 in which the sulfido group bridges the two ruthenium atoms.On the other hand the carboxylato derivatives (CO)5<μ-(PriO)2PN(Et)P(OPri)2>2>SbF6 (R''' = H, Me, Ph or CF3) are stable to decarbonylation in solution at room or elevated temperatures but can be decarbonylated to the carboxylato-bridged products 2-OC(R''')O>(CO)4<μ-(PriO)2PN(Et)P(OPri)2>2>SbF6 by irradiation with ultraviolet light.The water molecule in iO)2PN(Et)P(OPri)2>2>2 was also readily displaced by the conjugate bases of the above acids HA, but in contrast to that observed for the carboxylic acids R'''CO2H (R''' = H, Me or Ph), reaction of the aqua species with the corresponding carboxylate ions R'''CO2(1-) led to direct formation of the carboxylato-bridged species 2-OC(R''')O>(CO)4<μ-(PriO)2PN(Et)P(OPri)2>2>SbF6.Possible mechanisms for the formation of the various products are discussed as are the structures of iO)2PN(Et)P(OPri)2>2>2*OCMe2, 2-OC(OEt)>(CO)4<μ-(MeO)2PN(Et)P(OMe)2>2>SbF6, 2-OC(Me)O>(CO)4<μ-(PriO)2PN(Et)P(OPri)2>2>PF6 and 2-OC(O)>(CO)4<μ-(PriO)2PN(Et)P(OPri)2>2>, established X-ray crystallographically.
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Full text of DOI:10.1039/DT9930002735
