Abstract

<h2>Acta Crystallographica Section B</h2><h3>Structural Crystallography and Crystal Chemistry</h3><h3>0567-7408</h3> <h2>short structural papers</h2> Volume 36 Part 8 Pages 1972-1975 August 1980 <h2>Structure of dimethyl 4,4'-methylenebis(phenylcarbamate): a model for MDI units in polyurethane hard segments</h2> K. H. Gardner and J. Blackwell Acta Cryst. (1980). B36, 1972-1975 Structure of Dimethyl 4,4'-Methylenebis(phenylearbamate): a Model for MDI Units in Polyurethane Hard Segments BY K. H. GARDNER* AND J. BLACKWELL~f Department of Macromolecular Science, Case Western Reserve University, Cleveland, Ohio 44106, USA (Received 5 July 1978; accepted 19 March 1980) Abstract. Ct7HlsN204, monoclinic, P2t/b, a = 5.157 (3), b = 9.800(3), c = 31.472(11) A, ~ = 93.90 (3)°, Z = 4, Dm = 1.30, Dc = 1.316 Mg m-3. The structure was refined to R = 0.06 based on diffractometer data collected at 258 K. The molecule is V-shaped with a C-CH2-C angle of 114.5 (4)°. The angle between the phenyl-ring planes is 90.0° and the planes of the urethane groups are at angles of 10.2 and 39.4° to their adjacent phenyl rings. The molecules are linked into sheets by C=O...H-N hydrogen bonds between the urethane groups. The title com- pound furnishes a conformational model for the diol-linked 4,4'-methylenediphenyl diisocyanate (MDI) units in the