Cyclometalation of 2-Vinylpyridine with MCl2(PPh3)3and MHCl(PPh3)3(M = Ru, Os)

Treatment of RuCl 2 (PPh 3 ) 3 in benzene at room temperature with 2-vinylpyridine produces the vinylpyridine complex RuCl 2 (2-CH 2 CHC 5 H 4 N)(PPh 3 ) 2 . In the presence of Cs 2 CO 3, RuCl 2 (PPh 3 ) 3 reacts with 2-vinylpyridine at room temperature to give the cyclometalated complex RuCl(CH CHC 5 H 4 N)(CH 2 CHC 5 H 4 N)(PPh 3 ), which is also produced from the reaction of RuHCl(PPh 3 ) 3 with 2-vinylpyridine. OsCl 2 (PPh 3 ) 3 reacts with 2-vinylpyridine/Cs 2 CO 3 at room temperature to give the analogous cyclometalated complex OsCl(CH CHC 5 H 4 N)(CH 2 CHC 5 H 4 N)(PPh 3 ). In the presence of NaBF 4, the reaction produces [Os(CH CHC 5 H 4 N)(CH 2 CHC 5 H 4 N)(PPh 3 ) 2 ]BF 4 . The dihydrogen complex Os(H 2 )Cl(CH CHC 5 H 4 N)(PPh 3 ) 2 is produced from the reaction of OsHCl(PPh 3 ) 3 with 2-vinylpyridine. The mechanism of the cyclometalation reactions has been investigated by computational chemistry.