ISSN:
1572-8862
Keywords:
Triosmium complexes
;
metal cluster
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The reaction of Os3(CO)10(CNR)(NCMe) (1) with HCl was studied and this system was found to be a good model for observing the fine-tuning of site-selective protonation in metal complexes. Three products including the protonated species [(ε-H)Os3(CO)10(CNR)(NCMe)]+Cl− (2), the bridging aminocarbyne complex (µ-Cl)Os3(CO)10(µ2-C = NHR) (3), and the hydrido derivative (ε-H)Os3Cl(CO)10(CNR) (4) were obtained for the reaction. The site of protonation, either on the Os center or on the nitrogen atom of coordinated isocyanide, was tuned in a sensitive manner by the nature of the coordinated isocyanides, the polarity of the solvents, and the strengths of the acids, leading to different product distributions. The more electron withdrawing isocyanides (CNCH2Ph, CNPh) favor the formation of the aminocarbyne complex 3. In a nonpolar solvent like cyclohexane the reaction afforded 3 as the main product. Furthermore, complex 2 was converted to (ε-H)Os3(CO)10(ε2-CONHR) (5) upon hydrolysis, in which the coordinated isocyanide was transformed to a carboxamido group. This was verified by obtaining the deuterated species (ε-H)Os3(CO)10(ε2-CONDPr) when [(ε-H)Os3(CO)10(CNPr)(NCMe)]+Cl− (2a) was treated with D2O in THF. The molecular structures of (µ2-Cl)Os3(CO)10(µ2-C = NHCH2Ph) (3b) and (ε-H)Os3Cl(CO)10(CNPr) (4a) were determined by X-ray diffraction analyses. Complex 3b contains both bridging chloride and bridging aminocarbyne groups, whereas 4a contains a terminal chloride, a terminal isocyanide and a bridging hydride.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1021938532767
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