No abstract

New imidazolium salts, 1-(prop-2-ynyl)-3-vinyl-3H-imidazol-1-ium bromide, 1a, the tetraphenylborate, 1b, and hexafluorophosphate, 1c, salts of 1a and 3-allyl-1-(prop-2-ynyl)-3H-imidazol-1-ium bromide, 2a, containing alkene and alkyne groups for derivatisation were prepared from commercially available starting materials and fully3a, 3b or 3c, and [{µ 2 -HCCCH 2 N᎐ ᎐ C(H)N(CH 2 CH᎐ ᎐ CH 2 )CH᎐ ᎐ CH}Co 2 (CO) 6 ]BF 4 , 4a, and a new organometallic ionic liquid, [{µ 2 -HCCCH 2 N᎐ ᎐ C(H)N(CH 2 CH᎐ ᎐ CH 2 )CH᎐ ᎐ CH}Co 2 (CO) 6 ]PF 6 , 4b, were isolated by reacting 1a-c or 2a with Co 2 (CO) 8 . The compound 4b, the first ionic liquid bearing an organometallic moiety covalently attached to the cation, melts reversibly at 75-77 ЊC without decomposition. The imidazolium protons in 1b and 3b are shielded in the 1 H NMR as a result of π-interaction with the phenyl rings of the tetraphenylborate anion. The cation-anion contacts (C-H ؒ ؒ ؒ π ∼ 2.6 Å) observed in the molecular structure of 3b in the solid state are also maintained in solution, as evidenced in NOE NMR experiments. The molecular structures of 3b and 3c show an alkyne unit bonded to a Co 2 (CO) 6 fragment with the C᎐ ᎐ ᎐ C bond perpendicular to the Co-Co bond. † This paper is based on work presented at OMCOS 8 held at Santa Barbara, USA, 6-10 August 1995. Electronic supplementary information (ESI) available: Table of ionic liquids and melting points. See

No abstract

C 20 H 14 Fe, monoclinic, P 12 1 / n 1(no. 14), a =6.297(2) Å, b =12.825(2) Å, c =18.487(4) Å, b =90.57(2)°, V =1492.9 Å 3 , Z =4, R gt (F) =0.077, wR ref (F 2 ) =0.216, T =293 K. -Ferrocenyl-4-phenyl-1,3-butadiyne (CARN 1272-90-8) represents an asymmetricmonomer precursor for conjugated electroactive array models. Amodern method for the directed synthesis of the title compound by Cadiot-Chodkiewicz coupling of phenylethynea nd 1-bromo-2-ferrocenylethyne mediated by CuCl/NH 2 OH in modest yield(38 %) has been reported [1], although astatistical approach from phenylethyneand ferrocenylethyne using Cu(OAc)2 /pyridine with better yield (50 %) has been long known [2]. Surprisingly, the use of CuCl/TMEDA [3] in anothers tatistical oxidative coupling reaction gave an even more satisfactoryyield (74 %) of 1-ferrocenyl-4-phenyl-1,3-butadiyne. Suitable crystals were obtained by slow evaporation of a diethylether/pentane solution. The structure of closely related 1,4-diferrocenyl-1,3-butadiyne, which can be conveniently prepared by strictly following the method described for 1,4-diphenylbutadiyne [4], has been published twice [5,6], and acrystal structure of anew dimorph has also recently been reported [7]. Source of material1 Discussion

No abstract