W. Ries, I. Bernal
Nov 1, 1985
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Journal
Journal of Molecular Structure
Abstract
Abstract The structure of (R)-(+)-1-fluoro-2,2-diphyenylcyclopropanecarboxylic acid hereafter referred to as (1)) has been determined by single crystal X-ray diffraction methods. Crystals of (1) are orthorhombic, space group P212121, with cell constants: a = 6.172(9) A, b = 7.890(2) A and c = 27.091(7) A; cell volume, V = 1319.29 A3 and density (calc; z = 4 molecules per unit cell) = 1.290 g cm−3. A total of 1889 reflections were recorded in the range 4° 2δ(I). The refinement converged at R = 0.0448 and Rw = 0.0329. The molecule will be visualized as follows: the plane of the carboxylic group (defined by O1,O2,C1) is nearly orthogonal to the plane of the cyclopropane ring (dihedral angle 99.05°) while the dihedral angles between the two phenyl rings and the cyclopropane ring are, respectively, 117.77° and 63.16°. The carboxylic group is not in the bisecting conformation (with respect to the angle C4C2C3) as shown by the values of the torsional angles (−19.68°) and O2C1C2C4 (50.35°). This is a n hindrance between the cis-phenyl ring (C11, C12⋯C16) and the COOH substituent adjacent to it. One of the bonds within the cyclopropane ring is longer than the other two (1.563(9), 1.496(9), 1.494(8) A), the longer one being associated with the disubstituted carbons. The two CO bonds are 1.290(9) and 1.195(7) A, which are within the normally expected values. The rest of the bond lengths and angles are also normal. The molecules are hydrogen bonded into infinite chains running along the length of the a (shortest) axis of the lattice, the O⋯O distance being 2.638 A and the O1H and H⋯O2 distances being, respectively, 0.85(6) and 1.89(6) A. The O1H ⋯O angle is 146(7)°.