Mono- and bis-alkynyl ruthenium(II) complexes containing the ferrocenyl moiety; crystal structure of trans-[Ru(CCC 5H 4FeC 5H 5) 2(Ph 2PCH 2CH 2PPh 2) 2] and electrochemical studies

Abstract

The reaction of RuCl 2(Ph 2PCH 2CH 2PPh 2) 2 (RuCl 2(dppe) 2) with the terminal alkynes FcCCH or FcCCCCH (Fe = ferrocenyl = −C 5H 4FeC 5H 5) in the presence of NaPF 6 and a base afford mono- and bis-ferrocenylalkynyl-ruthenium complexes; Fe(CC) n RuCl(dppe) 2 ( n = 1 ( 2), 2 ( 7)); (Fe(CC) n ) 2Ru(dppe) 2 ( n = 1 ( 3), 2 ( 8i)); trans-(FeCC)FeCCCCRu(dppe) 2( 9). Starting from the vinylidene derivatives [XC 6H 4CHCRuCl(dppe) 2] 3 PF 6 ( 4) the bis mixed alkynyl derivaties trans-X-C 6H 4CCRuzCCFe(dppe) 2 (XH ( 5a), NO 2 ( 5b) and O 2NC 6H 4CCRuCCCFe(dppe) 2 ( 10) were formed. The protonation of 3 with NH 4 PF 6 allows access to [FeCCRu(NH 3)(dppe) 2[PF 6 ( 6). The X-ray structure of 3 was established. The redox properties of complexes 2–10 obtained by cylic voltammetry reveal that both ferrocenyl groups and Ru(dppe) 2 moieties oxidize reversibly. They especially show that the CC bridge, better than the CCCC bridge, but also the Ru(dppe) 2 moiety allow electronic communication from one of end of the linear organometallics molecule to the ferrocenyl group at the other end.