Adams Richard D, Akter Humaiara, Kaushal Meenal, Smith Mark D, Tedder Jonathan D
Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States.
Inorg Chem. 2021 Mar 15;60(6):3781-3793. doi: 10.1021/acs.inorgchem.0c03541. Epub 2021 Feb 22.
Reactions of the pentaruthenium cluster complexes Ru(μ-C)(CO) (), Ru(μ-C)(CO)μ-η-O═C(NMe) (), and Ru(μ-C)(CO)Cl(μ-H) () with ethyne (CH) in the presence of MeNO yielded the zwitterionic complexes Ru(μ-C)(CO)[μ-η-CHCH(NMe)] (), Ru(μ-C)(CO)μ-η-O═C(NMe) (), and Ru(μ-C)(CO)Clη--CH═CH(NMe) (). Each product contains a positively charged trimethylammonioethenyl ligand, CH═CH(NMe), that is derived from a 2-trimethylammonioethenide, CH═CH(NMe), zwitterion that formally has a positive charge on the nitrogen atom and a negative charge on the terminal enyl carbon atom. The trimethylammonioethenyl ligand, CH═CH(NMe) in is a η-ligand that bridges a Ru-Ru bond on a basal edge of the square-pyramidal Ru cluster by a combination of σ + π cooordination of the ethenyl group. Compounds and each contain a η-terminally coordinated [η--CH═CH(NMe)] ligand with an stereochemistry at the C═C double bond in open Ru cluster complexes. Compound was decarbonylated to yield the compound Ru(μ-C)(CO)[μ-η-O═C(NMe)]μ-η-CH═CH(NMe) () containing a η-bridging CHCH(NMe) ligand. Compound was converted back to by the addition of CO. Two zwitterionic products, Ru(μ-C)(CO)[η--CH═CH(NMe)] () and Ru(μ-C)(CO)[η--CH═CH(NMe)] (), were obtained by the addition of CO to . Compound is an intermediate en route to . Compound contains a terminally coordinated η--CH═CH(NMe) ligand on one of the basal Ru atoms of a square-pyramidal Ru cluster. Compound also contains a terminally coordinated η--CH═CH(NMe) ligand on the wing-tip bridging Ru atom of a butterfly RuC cluster. Treatment of with methyl propiolate (HC≡CCOMe) yielded the zwitterionic complex Ru(μ-C)(CO)[μ-η-O═C(NMe)]η--(MeOC)C═C(H)NMe () that is structurally similar to but contains a η--(MeOC)C═C(H)(NMe) ligand. Compound eliminated the NMe group to yield the compounds Ru(μ-C)(CO)[μ-η-O═C(NMe)][μ-η-(MeOC)HC═CH] () which contains a bridging methoxycarbonyl-substituted alkenyl ligand and the known compound Ru(μ-C)(CO)μ-η-O═C(NMe)(μ-H) ().
五钌簇合物Ru(μ-C)(CO) ()、Ru(μ-C)(CO)μ-η-O═C(NMe) ()和Ru(μ-C)(CO)Cl(μ-H) ()在MeNO存在下与乙炔(CH)反应，生成两性离子配合物Ru(μ-C)(CO)[μ-η-CHCH(NMe)] ()、Ru(μ-C)(CO)μ-η-O═C(NMe) ()和Ru(μ-C)(CO)Clη--CH═CH(NMe) ()。每个产物都含有一个带正电荷的三甲基铵乙烯基配体CH═CH(NMe)，它源自一个2-三甲基铵乙烯化物CH═CH(NMe)两性离子，该两性离子在形式上氮原子带正电荷，末端烯基碳原子带负电荷。中的三甲基铵乙烯基配体CH═CH(NMe)是一个η-配体，它通过乙烯基的σ + π配位作用在正方锥Ru簇的底边桥连Ru-Ru键。化合物和每个都含有一个η-末端配位的[η--CH═CH(NMe)]配体，在开放Ru簇配合物中C═C双键处具有立体化学结构。化合物脱羰生成含有η-桥连CHCH(NMe)配体的化合物Ru(μ-C)(CO)[μ-η-O═C(NMe)]μ-η-CH═CH(NMe) ()。通过添加CO，化合物又转化回。通过向中添加CO得到了两个两性离子产物Ru(μ-C)(CO)[η--CH═CH(NMe)] ()和Ru(μ-C)(CO)[η--CH═CH(NMe)] ()。化合物是生成过程中的中间体。化合物在正方锥Ru簇的一个底边Ru原子上含有一个末端配位的η--CH═CH(NMe)配体。化合物在蝶形RuC簇的翼尖桥连Ru原子上也含有一个末端配位的η--CH═CH(NMe)配体。用丙酸甲酯(HC≡CCOMe)处理得到两性离子配合物Ru(μ-C)(CO)[μ-η-O═C(NMe)]η--(MeOC)C═C(H)NMe ()，其结构与相似，但含有一个η--(MeOC)C═C(H)(NMe)配体。化合物消除NMe基团生成含有桥连甲氧基羰基取代烯基配体的化合物Ru(μ-C)(CO)[μ-η-O═C(NMe)][μ-η-(MeOC)HC═CH] ()和已知化合物Ru(μ-C)(CO)μ-η-O═C(NMe)(μ-H) ()。
