The half-sandwich 18-and 16-electron arene ruthenium iminophosphonamide complexesстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 24 марта 2017 г.
Аннотация:Novel half-sandwich 18 (e) over bar and 16 (e) over bar arene ruthenium iminophosphonamide complexes [(eta(6)-C6Me6)RuCl {(R'N)(2)PR2}] (3a-c) and [(eta(6)-C6Me6) Ru{(R'N)(2)PR2}](+)(X-) (4a-c) (a, R = Ph, R' = p-Tol; b, R = Et, R' = p-Tol; c, R = Ph, R' = Me. X = BF4, PF6 or BArF (4)) were synthesized. The elongated Ru-Cl bond in the 18 (e) over bar complexes is shown to dissociate even in apolar solvents to form the corresponding 16 (e) over bar cations, which can be readily isolated as salts with non-coordinating anions. The coordinatively unsaturated 16 (e) over bar complexes are stable species due to efficient pi-electron donation from the nitrogen atoms of the zwitterionic NPN-ligand. The ruthenium iminophosphonamides are moderately active in the ROMP polymerization of norbornene; the 16 (e) over bar complexes 4a, b yield high molecular weight polymers (M-n similar to 300 x 10(3)) with a narrow distribution M-w/M-n similar to 1.6, while the 18 (e) over bar complexes 3a, b give polymers of lower molecular weight (M-n < 50 x 10(3)) with a wider polydispersity index M-w/M-n similar to 2.5.