para-Ethynyl aniline as a building block for fully pi-conjugated ligands and acetylide complexes: crystal structures of trans-[Pt(PPh3)(2)(C CC6H4NH2)(2)] and [(mu-H)Ru-3(CO)(9)(mu(3)-C CC6H4NH2)]

para-Ethynyl aniline has been prepared, structurally characterised and inve stigated as a building block towards fully pi -conjugated multifunctional l igands and complexes. Palladium-copper catalysed coupling with aryl halides affords a number of new amino-substituted aryl acetylenes, while using [Ni (CO)(2)(PPh3)(2)] as a catalyst, cyclotrimerisation and dimerisation to giv e an ene-yne were competitive. Reaction of para-ethynyl aniline with low-va lent metal centres affords acetylide complexes trans[Pt(PR3)(2)(C=CC6H4NH2) (2)] (R = Ph, Bu-n), cis-[Pt(eta (2)-dppe)(C=CC6H4NH2)(2)], all trans-[Ru(C O)(2)(PEt3)(2)(C=CC6H4NH2)(2)] and [(muH)Ru-3(CO)(9)(mu C-3=CC6H4NH2)]. The bis(acetylide) trans-[Pt(PPh3)(2)(C=CC6H4NH2)(2)] has been used to prepare extended chain complexes with amide, imine, imino-phosphorane and ferrocen yl imine units being generated. Attempts to prepare polymers via reaction w ith terephthaloyl chloride lead only to the formation of oligomers with an average of four monomer units. (C) 2000 Elsevier Science B.V. All rights re served.