189288-33-3Relevant academic research and scientific papers
Liquid-Crystalline Mono- And Dinuclear (Perhalophenyl)gold(I) Isocyanide Complexes
Bayón, Rocio,Coco, Silverio,Espinet, Pablo,Fernández-Mayordomo, César,Martín-Alvarez, José M.
, p. 2329 - 2334 (2008/10/09)
Rodlike gold(I) and gold(III) complexes [AuR(C≡N(C6H4)mOCnH 2n+1-p)] (m = 1, n = 10, R = C6F5; m = 2, n = 4, 6, 8, 10, 12, R = C6F5, C6F4Br-o, C6F4Br-p), [(μ-4,4′C6F4C6F 4){AuC≡N(C6H4)mOC nH2n+1}2] (m = l, 2; n = 4, 6, 8, 10, 12), [AuRI2(C≡NC6H4C6H 4OCnH2n+1-p)] (R = C6F5, n = 8; R = C6F4Br-o, n = 10), and [(μ-4,4′-C6F4C6F4){AuX 2C≡N(C6H4)mOC nH2n+1}2] (m = l, 2; n = 4, 6, 8, 10, 12) have been prepared and their liquid crystal behavior has been studied. The gold(III) compounds are not mesomorphic, but all the perhalogold(I) derivatives described are liquid crystals except the phenyl isocyanide gold(I) derivative [Au(C6F5)(C≡NC6H4OC 10H21-p)]. The mononuclear derivatives show only a nematic (N) phase when the isocyanides have a short tail (n = 4), N and smectic A phases (SA) when the isocyanides have an intermediate tail (n = 6, 8), and only SA phases for longer chains. Their thermal stability is high, even in the isotropic state. The variation in transition temperatures is as follows: C6F4Br-p ≥ C6F5 > C6F4Br-o when n ≤ 6 and C6F4Br-p > C6F4Br-o > C6F5 for n ≥ 8. This behavior is understood on the basis of electronic and steric factors. The dinuclear compounds [(μ4,4′-C6F4C6F 4){AuC≡N(C6H4)mOC nH2n+1}2] display only N mesophases and all the biphenylisocyanide derivatives and phenyl isocyanide compounds with n ≤ 6 undergo some decomposition upon reaching the clearing point to the isotropic state.
