MONO-ALKYNYL AND BIS-ALKYNYL RUTHENIUM(II) COMPLEXES CONTAINING THE FERROCENYL MOIETY - CRYSTAL-STRUCTURE OF TRANS-[RU(CCC5H4FEC5H5)(2)(PH2PCH2CH2PPH2)(2)] AND ELECTROCHEMICAL STUDIES

The reaction of RuCl2(Ph2PCH2CH2PPh2)(2) (RuCl2(dppe)(2)) with the ter minal alkynes FcC=CH or FcC=C-C=CH (Fc=ferrocenyl=-C5H4FeC5H5) in the presence of NaPF6 and a base afford mono- and bis-ferrocenylalkynyl-ru thenium complexes: Fc(C=C)(n)RuCl(dppe)(2) (n=1 (2), 2 (7)); (Fc(C=C)( n))(2)Ru(dppe)(2) (n=1 (3), 2 (8)); trans-(FcC=C)FcC=C-C=C-Ru(dppe)(2) (9). Starting from the vinylidene derivatives [X-C6H4CH=C=RuCl(dppe)( 2)]+PF6- (4) the bis mixed alkynyl derivatives trans-X-C6H4-C=C-Ru-C=C -Fc(dppe)(2) (X=H (5a), NO2 (5b)) and O2N-C6H4-C=C-Ru-C=C-C=C-Fc(dppe) (2) (10) were formed. The protonation of 3 with NH4+PF6- allows access to [FcC=C-Ru(NH3)(dppe)(2)]PF6 (6). The X-ray structure of 3 was esta blished. The redox properties of complexes 2-10 obtained by cylic volt ammetry reveal that both ferrocenyl groups and Ru(dppe)(2) moieties ox idize reversibly. They especially show that the C=C bridge, butter tha n the C=C-C=C bridge, but also the Ru(dppe)(2) moiety allow electronic communication from one end of the linear organometallic molecule to t he ferrocenyl group at the other end. (C) 1998 Elsevier Science S.A. A ll rights reserved.