143142-19-2Relevant academic research and scientific papers
Structural study in the oligomethylene dithiobenzoate series, nDBS, where n, the number of methylene groups, is odd
Leblanc, Claude,Brisse, Francois
, p. 900 - 909 (2007/10/02)
Model compounds of the poly(oligomethylene thioterephthalates) have been synthesized and characterized by X-ray diffraction analyses.The pink n-methylenedithiobenzoates, obtained for n = 3, 5, 7, and 9, all have a low melting point of about 320-330 K.They all crystallize in the monoclinic system, space group P21/c.The a and b unit cell dimensions vary little while the c dimension increases monotonically as n changes from 3 to 9.The crystal structures of the four compounds were established from low-temperature X-ray intensities.Except for the lengthening of the methylenic sequence, the four molecules studied here are isostructural.One of the thiobenzoate groups of the molecules is coplanar with all the methylenic carbons, while the other thiobenzoate group is at 90 deg from the above plane of atoms.The methylenic sequence has the same conformation.It may be decribed by g+(t)n, where n is the number of methylene groups.Thus, the four compounds belong to a crystallographically homologous series.The molecules form centrosymmetric "dimers", which, in turn, are herring-bone packed in their respective unit cells.In each "dimer" two aromatic rings are across from another while being mutually perpendicular.On the basis of the above results, one proposes three potentially acceptable structures for the parent poly(oligomethylene thioterephthalates). Key words: dithiobenzoate, methylene sequence, crystal structure, poly(oligomethylene thioterephthalate)
