Yen Yung-Sheng, Lin Ying-Chih, Huang Shou-Ling, Liu Yi-Hung, Sung Hui-Ling, Wang Yu
Department of Chemistry, National Taiwan University, Taipei, Taiwan 106, Republic of China.
J Am Chem Soc. 2005 Dec 28;127(51):18037-45. doi: 10.1021/ja054994a.
The cationic complex {[Ru]=C=CHCPh2CH2CH=CH2}BF4 (3a, [Ru] = (eta5-C5H5)(PPh3)2Ru) in solution transforms to {[Ru]=C=CHCH2CPh2CH=CH2}BF4 (4a) via a new metathesis process of the terminal vinyl group with the C=C of the vinylidene group which is confirmed by 13C labeling studies. This transformation is irreversible as revealed by deuteration and decomplexation studies. The cationic complex {[Ru]=C=CHCPh2CH2CMe=CH2}BF4 (3b) undergoes a cyclization process yielding 6b containing a eta2-cyclic allene ligand which is fully characterized by single-crystal X-ray diffraction analysis. Analogous complexes 4a' and 6b' ([Ru] = (eta5-C5H5)(dppe)Ru) containing dppe ligands were similarly obtained from protonation of the corresponding acetylide complexes via formation of vinylidene intermediate. Protonation of the acetylide complex containing a terminal alkynyl group [Ru]-CCCPh2CH2CCH (2c) generates the vinylidene complex {[Ru]=C=CHCPh2CH2CCH}BF4 (3c) which again undergoes an irreversible transformation to give {[Ru]=C=CHCH2CPh2CCH}BF4 (4c) possibly via a pi-coordinated alkynyl complex followed by hydrogen and metal migration. No similar transformation is observed for the analogous dppe complex 3c'. With an extra methylene group, complex {[Ru]=C=CHCPh2CH2CH2CH=CH2}BF4 (3d) and complex {[Ru]=C=CHCPh2CH2Ph}BF4 (3e) are stable. The presence of a gem-diphenylmethylene moiety at the vinylidene ligand with the appropriate terminal vinyl or alkynyl group along with the correct steric environment implements such a novel reactivity in the ruthenium vinylidene complexes.
阳离子配合物{[Ru]=C=CHCPh2CH2CH=CH2}BF4（3a，[Ru] = (η5-C5H5)(PPh3)2Ru）在溶液中通过末端乙烯基与亚乙烯基的C=C之间的一种新的复分解过程转化为{[Ru]=C=CHCH2CPh2CH=CH2}BF4（4a），这一过程通过13C标记研究得到证实。氘代和解络合研究表明，这种转化是不可逆的。阳离子配合物{[Ru]=C=CHCPh2CH2CMe=CH2}BF4（3b）经历环化过程，生成含有η2-环状丙二烯配体的6b，其通过单晶X射线衍射分析得到充分表征。类似地，含有dppe配体的类似配合物4a'和6b'（[Ru] = (η5-C5H5)(dppe)Ru）通过相应乙炔配合物质子化并经由亚乙烯基中间体形成而得到。含有末端炔基的乙炔配合物[Ru]-CCCPh2CH2CCH（2c）质子化生成亚乙烯基配合物{[Ru]=C=CHCPh2CH2CCH}BF4（3c），其再次经历不可逆转化，可能通过π-配位的炔基配合物，随后发生氢和金属迁移，生成{[Ru]=C=CHCH2CPh2CCH}BF4（4c）。对于类似的dppe配合物3c'，未观察到类似的转化。具有额外亚甲基的配合物{[Ru]=C=CHCPh2CH2CH2CH=CH2}BF4（3d）和配合物{[Ru]=C=CHCPh2CH2Ph}BF4（3e）是稳定的。在亚乙烯基配体上存在偕二苯基亚甲基部分以及合适的末端乙烯基或炔基，再加上正确的空间环境，使得钌亚乙烯基配合物具有这种新颖的反应性。
