名称:
Structure of trans,trans-4,4'-di(methoxycarbonylimino)dicyclohexylmethane: a model for trans,trans-4,4'-diisocyanatodicyclohexylmethane/1,4-butanediol-based units in polyurethane hard segments
摘要:
C17H30N2O4, monoclinic, P2(1)/n, a = 17.963 (4), b = 6.290(2), c = 18.214(4)angstrom, beta = 116.59(3)-degrees, V = 1840.3 (8) angstrom3, Z = 4, D(m) = 1.16, D(x) = 1.178 Mg m-3, T = 173 K, F(000) = 712, final weighted wR = 0.039 for 3231 observed independent reflections. The bridge C-CH2-C angle of the V-shaped title compound is 116.1(2)-degrees. Both cyclohexyl rings have chair conformations and are mutually inclined at 55.1-degrees. The angles between the cyclohexyl rings and the adjacent urethane groups are 101,5 and 66.2-degrees. The molecules are linked by four intermolecular C=O...H-N hydrogen bonds per monomer unit. Two hydrogen bonds are formed between neighbouring molecules similar to a dimerization. The two residual hydrogen bonds of a monomer unit are formed to different molecules. The structural analysis of the model compound allows the construction of the packing and conformation of the 1,4-butanediol-linked trans,trans-diisocyanatodicyclohexylmethane (trans,trans-HMDI) units in the hard domains of the corresponding polyurethane elastomers.