Structural investigations of phosphorus-nitrogen compounds. 4. Steric and electronic effects in dibenzylamino derivatives of hexachlorocyclotriphosphazatriene and 4,4,6,6-tetrachloro-2,2-diphenylcyclotriphosphazatriene
Besli, S., Coles, S. J., Davies, D. B., Hursthouse, M. B., Kilic, A., Mayer, T. A., Shaw, R. A. and Uslu, A. (2002) Structural investigations of phosphorus-nitrogen compounds. 4. Steric and electronic effects in dibenzylamino derivatives of hexachlorocyclotriphosphazatriene and 4,4,6,6-tetrachloro-2,2-diphenylcyclotriphosphazatriene. Acta Crystallographica Section B: Structural Science, 58, 545-552. (doi:10.1107/S0108768102003816).
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Description/Abstract
A systematic study is presented on the products of aminolysis of N3P3Cl6 (1) and N3P3Ph2Cl4 (4) with dibenzylamine. Two series of mono- and disubstituted derivatives of compounds (1) and (4), namely N3P3Cl5 [N(CH2Ph)(2)] (2) and N3P3Cl4 [N(CH2Ph)(2)](2) (3) and N3P3Ph2Cl3 [N(CH2Ph)(2)] (5) and N3P3Ph2Cl2 [N(CH2Ph)(2)](2) (6) [where (2), (3), (5) and (6) are new structures], are investigated in order to determine whether steric or electronic effects prevail in the formation of dibenzylamino-substituted cyclophosphazenes. The influence of an electron-releasing group (i.e. phenyl) on the stereochemistry and degree of substitution of the product is analysed by comparison of the above two series. The difference in unsymmetrically substituted endocyclic P-N bond lengths, Delta, is used as a measure of the degree of the electronic contribution, in combination with basicity constants, to quantify the degree of the electron-releasing capacity of the R group. In order to compare geminal versus non-geminal substitution, a difunctional secondary amine was used to form the compound N3P3Cl4 [NMe(CH2)(3) NMe] (7) (a reinvestigation) for inclusion in this study. It is shown that electron-releasing groups have a greater effect on the lengthening of P-Cl bonds as opposed to endocyclic P-N bonds and that this effect is greater in the non-geminal PRCl case than for geminal PCl2. However, steric effects are shown to be dominant in the reactions of dibenzylamine with N3P3 derivatives, with a disposition to a trans stereochemistry in bisdibenzylamino derivatives.
| Item Type: | Article |
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| Related URLs: | |
| Keywords: | crystal, products, bond |
| Subjects: | Q Science Q Science > QD Chemistry |
| Divisions: | University Structure - Pre August 2011 > School of Chemistry |
| Item ID: | 19675 |
| Date Deposited: | 16 Feb 2006 |
| Last Modified: | 01 Jun 2011 01:48 |
| Contributors: | Besli, S. (Author) Coles, S. J. (Author) Davies, D. B. (Author) Hursthouse, M. B. (Author) Kilic, A. (Author) Mayer, T. A. (Author) Shaw, R. A. (Author) Uslu, A. (Author) |
| Date: | 1 June 2002 |
| Status: | Published |
| URI: | http://eprints.soton.ac.uk/id/eprint/19675 |
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