The reactions of a series of 1-halopolyynes with secondary amines led to novel amine end-capped polyynes exhibiting surprisingly high stability toward moisture. The new compounds were characterized by NMR spectroscopy, ESI-MS spectrometry, and X-ray single-crystal diffractometry. The use of amine end-capped polyynes as precursors to substituted push-pull thiophenes was next presented. The results show the first-to the best of our knowledge-transformation of ynamine to thiophene and the first regioselective transformation of a longer polyynes to butadiyne-substituted thiophene. Photophysical studies of the resulting compounds show that some of the substituted thiophenes have high quantum yield photoluminescence upon UV light irradiation.

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Polyynes are compounds with two or more conjugated carbon–carbon triple bonds. Such molecules are usually regarded as models of carbynea hypothetical one-dimensional allotropic form of carbon. 1-Halopolyynes are rare representatives of such species, but few interesting crystal-to-crystal reactions have been recently reported for them. Herein, we present 11 new X-ray structures of 1-halopolyynes, nearly doubling the number of such compounds characterized with the use of single-crystal X-ray diffraction. The influence of an end-group on packing motifs in crystal structures of the 1-halopolyynes were thoroughly examined. Especially the strength of halogen bond as a function of polyyne chain length was analyzed with the support of theoretical calculations. Moreover, the compound CNC 8 I is the longest 1-halopolyyne characterized to date with the use of rentgenostructural analysis. In addition to that, the compounds NO 2 C 6 Br and MeC­(O)­C 6 Br are the first 1-bromohexatriynes characterized by means of X-ray single-crystal diffraction.

Synthesis of complex di(selenophen-3-yl)diselenides and 3-methylene-3 H -1,2-diselenoles directly from 1-bromobutadiynes is described. The transformation is performed under conditions used before for the synthesis of simple selenophenes from butadiynes. The reaction is operationally straightforward, and complex products were obtained in high yields. Structures of the final products were unambiguously confirmed by the means of 77 Se NMR and single-crystal X-ray diffraction.