para-Ethynyl aniline as a building block for fully π-conjugated ligands and acetylide complexes:: crystal structures of trans-[Pt(PPh3)2(CCC6H4NH2)2] and [(μ-H)Ru3(CO)9(μ3-CCC6H4NH2)]

para-Ethynyl aniline has been prepared, structurally characterised and investigated as a building block towards fully pi -conjugated multifunctional ligands 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 give an ene-yne were competitive. Reaction of para-ethynyl aniline with low-valent 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(CO)(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 ferrocenyl imine units being generated. Attempts to prepare polymers via reaction with terephthaloyl chloride lead only to the formation of oligomers with an average of four monomer units. (C) 2000 Elsevier Science B.V. All rights reserved.