Showing papers by "Brian J. Orr published in 1966"
TL;DR: In this paper, the determinability of aliphatic C-C and C-H bonds is reviewed and the effect of small deviations from tetrahedral bond angles on the determinable polarisability parameters of alicyclic molecules is considered.
Abstract: Previous determinations of the anisotropic polarisability of aliphatic C–C and C–H bonds are reviewed. Kerr-effect measurements of several alicyclic hydrocarbons in solution and as pure liquids are reported, and previous measurements are reconsidered. The parameter ΓCC≡(bLCC–bTCC)–2(bLCH–bTCH) is evaluated from eight independent determinations in solution as 0·71 ± 0·3 A3, and from five determinations for liquids as 0·80 ± 0·15 A3, in good agreement with recent light-scattering results. Methods of obtaining C–C and C–H bond polarisabilities separately are discussed, and consideration given to the effect of small deviations from tetrahedral bond angles on the determinable polarisability parameters of aliphatic molecules. The conformation of the cyclooctane ring is investigated, but results are inconclusive.
28 citations
TL;DR: In this article, the dipole moments, p, and molar Kerr constants, m(rnKz), of benzotrichloride and benzal chloride as solutes in carbon tetrachloride at 25 were measured.
Abstract: I n the course of a continuing study of environmental variations in the anisotropic polarizabilities of carbon-halogen bonds (see refs. listed as 1-7 by Izs&k and Le FBvrel) we have measured the dipole moments, p, and molar Kerr constants, m(rnKz), of benzotrichloride and benzal chloride as solutes in carbon tetrachloride at 25\". Experimental observations and results are shown in Tables 1 and 2; symbols are as defined elsewhere.2 The dipole moments (2.03 D and 2.07 D, respectively) are in good agreement with recorded values.3 The applicability of available carbonchlorine bond anisotropies has been tested by comparison of observed and calculated molar Kerr constants for these two molecules. Results previously recorded4 for benzotrifluoride have also been considered.
6 citations
TL;DR: The molar Kerr constants and dipole moments, measured at infinite dilution in carbon tetrachloride, of t-butyl, ethyl, n-propyl and n-hexyl chloride are recorded in this article.
Abstract: The molar Kerr constants and dipole moments, measured at infinite dilution in carbon tetrachloride, of t-butyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl chloride are recorded. Inductive effects in these molecules are briefly discussed. Estimates of the anisotropic polarisability of the C–Cl bond in t-butyl and ethyl chloride are obtained. Molar Kerr constants of the n-alkyl chlorides lie in the range +56 to 62 × 10–12. Expectation values of the molar Kerr constants, obtained by a treatment previously applied to n-alkyl bromides and iodides, are in excellent agreement with experiment. For n-propyl chloride, the gauche–trans energy difference is found to be +0·14± 0·1 kcal./mole.
4 citations
TL;DR: In this paper, anisotropic polarisabilities (bL= 3·79, bT=bv= 1·26) for the C≡C bond, deduced from literature data, are satisfactorily applicable to 3-chloropropyne, 3-bromopropne, and phenylacetylene, as solutes in carbon tetrachloride.
Abstract: Dipole moments and molar Kerr constants at 25° are recorded for 3-chloropropyne, 3-bromopropyne, phenylacetylene, diphenylacetylene, di-(p-chlorophenyl)acetylene, and dimethyl and diethyl acetylenedicarboxylate, as solutes in carbon tetrachloride. Anisotropic polarisabilities (bL= 3·79, bT=bv= 1·26) for the C≡C bond, deduced from literature data, are satisfactorily applicable to 3-chloropropyne, 3-bromopropyne, and phenylacetylene. Observations on the esters can be interpreted in terms of a mixture of non-planar cis- and trans-isomers.
4 citations