Abstract
The clusters [Ru 3(CO) 12− n (RCN) n ] ( n = 1–3; RCN = acetonitrile, adiponitrile, phenylenediacetonitrile) have been prepared in dichloromethane solution by reaction of [Ru 3(CO) 12] with Me 3NO in the presence of the desired nitrile. The number of coordinated nitriles depends on the nitrile concentration and to a lesser extend on the Me 3NO/Ru 3 ration. The new cluster [Ru 3(CO) 9(MeCN) 3] is prepared and isolated in high yield. Spectroscopic IR and 13C NMR investigations in solution indicate that the dinitriles remain monocoordinated but only in a concentrated medium (1M <[RCN] < 4M). Spectroscopic data suggest axial coordination of the nitriles, one on each ruthenium atom, and equatorial bridging carbonyl groups. For [Ru 3(CO) 7( μ 2−CO) 3(MeCN) 2], the two nitriles are located on each side of the triruthenium plane, whereas for [Ru 3(CO) 6( μ 2−CO) 3(MeCN) 3], two MeCN are located on one side of the triruthenium plane with the third lying on the other side. Variable-temperature 13C NMR study reveals a fluxionality of the carbonyls around the trimetal core. The first fluxional motion involves in-plane carbonyl exchange with activation energies depending on the degree of substitution n. The influence of ligand substitution in the axial position on the mobility of the carbonyls is attributed to an increase of the π back-donation from the cluster to each of the remaining carbonyls with increasing substitution.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.