1,2,3-Triazolylidene ruthenium(ii)-cyclometalated complexes and olefin selective hydrogenation catalysisElectronic supplementary information (ESI) available. CCDC 1028679-1028683. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c4dt03156c

Silver( i ) 1,2,3-triazol-5-ylidenes [(RCH 2 C 2 N 2 (NMe)Ph) 2 Ag][AgCl 2 ] (R = Ph 3a , C 6 H 2 iPr 3 3b , C 6 H 2 Me 3 3c ) and [(PhCH 2 C 2 N 2 (NMe)R) 2 Ag][AgCl 2 ] (R = C 6 H 4 Me 3d , C 6 H 4 CF 3 3e ) were synthesized and subsequently treated with RuHCl(PPh 3 ) 3 and RuHCl(H 2 )(PCy 3 ) 2 . The reaction of 3a with RuHCl(PPh 3 ) 3 gave RuHCl(PPh 3 ) 2 (PhCH 2 C 2 N 2 (NMe)Ph) ( 4a 1 ) as the minor product and the cyclometalated complex RuCl(PPh 3 ) 2 (PhCH 2 C 2 N 2 (NMe)C 6 H 4 ) ( 4a 2 ) as the major product. However, similar reaction with 3b selectively formed the cyclometalated complex RuCl(PPh 3 ) 2 ((C 6 H 2 iPr 3 )CH 2 C 2 N 2 (NMe)C 6 H 4 ) ( 4b 2 ). Similarly the silver( i ) triazolylidenes 3a and 3b were reacted with RuHCl(H 2 )(PCy 3 ) 2 ; gave RuHCl(PCy 3 ) 2 (PhCH 2 C 2 N 2 (NMe)Ph) ( 5a 1 ), RuCl(PCy 3 ) 2 (PhCH 2 C 2 N 2 (NMe)C 6 H 4 ) ( 5a 2 ) and RuCl(PCy 3 ) 2 ((C 6 H 2 iPr 3 )CH 2 C 2 N 2 (NMe)C 6 H 4 ) ( 5b 2 ), respectively. Species 3c , 3d and 3e resulted in the cyclometalated complexes ( 5c 2 , 5d 2 and 5e 2 ) as the major products as well as the ruthenium-hydride complexes ( 5c 1 , 5d 1 and 5e 1 ) as the minor products. The cyclometalated species are derived from the ruthenium-hydride complexes via C(sp 2 )-H activation. These Ru-complexes were shown to act as hydrogenation catalyst precursors for olefinic substrates including those containing a variety of functional groups. Silver( i ) 1,2,3-triazol-5-ylidenes [(RCH 2 C 2 N 2 (NMe)Ph) 2 Ag][AgCl 2 ] (R = Ph 3a , C 6 H 2 iPr 3 3b , C 6 H 2 Me 3 3c ) and [(PhCH 2 C 2 N 2 (NMe)R) 2 Ag][AgCl 2 ] (R = C 6 H 4 Me 3d , C 6 H 4 CF 3 3e ) were synthesized and subsequently treated with RuHCl(PPh 3 ) 3 and RuHCl(H 2 )(PCy 3 ) 2 to give cyclometallated and Ru-hydride species as the major and minor products, respectively.