Asymmetrie Ethynes. Syntheses of Ethynylferrocene Paradigms

Abstract

Synthetic methods to bifunctional ethynes have been examined. Direct ethynylation, the Stephens-Castro reaction, the Pd-catalysed Hagihara coupling, transmetalation reactions and nucleophilic additions have been evaluated in the preparation of substituted ferrocenylethynes with intended use of these materials in electrochemical and nonlinear optical investigations. Asymmetric ferrocenylethynes are promising candidates for applications in contemporary materials science. Synthetically, 1,4-bis(ferrocenylethynylene)benzene (1), 1,3,5-tris(ferrocenylethynylene) benzene (2), and 9 ,10-bis(ferrocenylethynylene)anthracene (3) are obtained in high yields, whereas 4-ferrocenylethynylene-2,3,5,6-tetrafluorostyrene (4) and potassium (ferrocenylethynylene) triphenyl borate (5) are accessible in only moderate yields. Further extension of this chemistry to additional heteronuclear bimetallic coordination compounds has been attempted, but without success due to severe difficulties in both preparation and characterization of these materials.

Cationic and Neutral [4]-Cumulenes CCCCC with Five Cumulated Carbons and Three to Four Ferrocenyl Termini

“…Cross coupling of 1 with ferrocenylethynylcopper in pyridine as solvent yielded triferrocenyl-C 5 -methoxypentadiyne ( 2a ), together with triferrocenyl-C 5 - hydroxypentadiyne ( 2b ), formed in part by unavoidable hydrolysis of preparative amounts of crude 2a during chromatographic workup on basic alumina. The use of basic alumina was necessary to avoid dehydration of 2a to cation 3 , which cannot be eluted from the stationary phase due to immobilization.…”

Oligo(ethynylene-p-phenylen)ic and Benzilic Spacers for the Modular Construction of Organometallic NLO-Phores

“…The same strategy but different types of precursors yielded ferrocenyl(C1 SHE-ethynylene-ppheny1ene)trimethylsilane [6a]. The target compound potassium ferrocenyl(C1sHs-ethynylene-ppheny1ene)triphenyl borate, which should be accessible from direct ethynylation according to compound 13 and potassium(ferroceny1ethynylene)triphenylborate [35], could not be clearly characterized. Functionalization of B e d Derivatives.…”