Crystal Structure and Phase Transformation of Trichloroethylidene Trichlorolactic Ester (Chloralide), Cl₃CCHOCOCHOCCl₃. An X‐Ray and NQR Study

Abstract

Trichloroethylidene trichlorolactic ester (Chloralide), CI,C~HOCOCH?CCI,, crystallizes at room temperature (T = 298 K) monoclinic, space group C: , -P2,/c, with 4 molecules in the unit cell. The lattice constants are a = (619.94 * 0.20) pm, b = (1716.3 * 0.6) pm, c = (1037.0 f 0.3) pm, p = 95.083" k 0.010". The crystal structure was determined with a reliability factor R = 0.044 (1638 symmetry independent reflexes with I > a ( [ ) ) . At 343 5 T/K 5 344 a phase transformation occurs, which shows super heating phenomena. -In the "C1-NQR the 6 line low temperature spectrum 38.178 5 v/MHz 5 40.178 at T = 77 K is in accordance with the crystal structure. By intensity considerations an assignment of the spectrum of the two different CCI, groups in the molecule was possible. The high temperature phase of Chloralide shows the fade out phenomenon in the NQR-spectrum due to hindered rotations of one of the two CCl, groups. The kinetics of the transformation phase I1 -+ phase I is of first order. Ber. Bunsenges. Phys. Chem. 84, 883 -890 (1980) -0 Verlag Chemie, D-6940 Weinheim, 1980. 0005 -9021/80/0909 -0883 $ 02.5010 884 M. Hashimoto, H. Paulus, and A. Weiss: Crystal Structure and Phase Transformation of Trichloroethylidene etc. Trichlorathyliden-trichlormilchsiiureester (Chloralid), CI,C~HOCOCH?CCI,, kristallisiert bei T = 298 K monoklin, mit der Raumgruppe C: , -P2,/c, und 4 Molekiilen in der Elementarzelle. Die Gitterkonstanten sind: a = (619,94 & 0,20) pm, b = (1716,3 f 0.6) pm, c = (1037,O f 0,3) pm, / 3 = 95,083" 1 0,010'. Die Kristallstruktur wurde mit einem Zuverlassigkeitsfaktor R = 0,044 bestimmt (1638 symmetrieunabhangige Reflexe mit Z > ~( 1 ) ) . Bei T = 343 . .. 344K findet eine Phasentransformation statt, die ifberhitzungserscheinungen zeigt. -Im Tieftemperatur-35C1-NQR-Spektrum wurden 6 Linien beobachtet, (38,178 5 v/MHz 5 40,178 bei T = 77K), deren Zahl in Ubereinstimmung mit der Kristallstruktur der Phase I1 ist. Durch IntensitPtsbeobachtungen ist eine Zuordnung der NQR-Linien zu den zwei kristallographisch verschiedenen CCI,-Gruppen des Molekiils mOglich. Die Hochtemperaturphase des Chloralids zeigt im NQR-Spektrum die "fade-out"-Erscheinung, die durch gehemmte Rotationen einer der CCI3-Gruppen hervorgerufen wird. Die Kinetik der Phasentransformation Phase I1 + Phase I ist von 1. Ordnung.

Crystal and molecular structure of (2S,5S)-2-t-butyl-5-phenyl-1,3-dioxolan-4-one, C13H16O3

“…The envelope conformation of five-membered ring is typical for analogous y-lactones (Jeffrey et al, 1967;Harlow and Simonsen, 1976;Bocelli and Grenier-Loustalot, 1981), although it differs significantly from the three known structures of 1,3-dioxolan-4-ones derived from chloral (chloralides) which are nearly planar (Hashimoto et al, 1980;Brettle et al, 1983). This difference may result from dipole-dipole interactions of the trichloromethyl group with the dioxolanone ring and the ira/w-substitution of the rings of these chloralides.…”

The combination of X-ray diffraction and nuclear quadrupole resonance studies of crystals

“…It is, however, for the theory of the C--C1 (C--Br) bond, also of importance because r/(35C1) will be much smaller than in aromatic systems and more sensitive to intermolecular interactions. Hashimoto, Paulus & Weiss (1980) have studied the structure and phase transition of trichloroethylidene trichlorolactic ester (chloralide) and its single-crystal 35C1 NQR spectrum (Hashimoto, Nagarajan, Weiden & Weiss, 1983). Also ot-2,4,6-tris(trichloromethyl)-l,3,5-trioxane (c~-parachloral) was studied (Hashimoto, Weiden & Weiss, 1985), the structure of which was known (Hay & Mackay, 1980).…”