The Raman spectrum of polycrystalline or matrix-isolated S<sub>2</sub>N<sub>2</sub> shows three bands attributable to its Raman active fundamentals, including two in close proximity; the possibility of Fermi resonance is discounted. The infrared spectrum.of polycrystalline S<sub>2</sub>N<sub>2</sub> shows five bands, including three attributable to the infrared active fundamentals, while the others are associated with some intermediate species in the polymerisation of S<sub>2</sub>N<sub>2</sub>. The vibrational spectra of matrix-isolated S<sub>4</sub>N<sub>4</sub> are consistent with previous observations in the solid state and in solution, also with the established cage structure of the molecule. The stretching force constants of S<sub>2</sub>N<sub>2</sub> and S<sub>4</sub>N<sub>4</sub>, lower than those predicted on the basis of observations on acyclic S-N molecules, are correlated with the strain in the molecules and their associated thermodynamic instability. The interaction force constants indicate delocalised π-bonding, apparently more extensive in S<sub>2</sub>N<sub>2</sub>. Substantial cross-ring S-S bonding is evident in S<sub>4</sub>N<sub>4</sub>; S-S interactions in S<sub>2</sub>N<sub>2</sub> are apparently non-bonded and repulsive in nature. The infrared spectrum of matrix-isolated Cr0C1<sub>3</sub> contains bands attributable to the fundamentals of this molecule, along with several indicating the presence of Cr0<sub>2</sub>C1<sub>2</sub> and possibly other related molecules. The Raman spectrum shows just three strong bands, all below 250 cm<sup>-1</sup>, assumed to arise from the deformation fundamentals of Cr0C1<sub>3</sub>; the form of the spectrum is attributed to absorption or fluorescence. The force constants derived for Cr0C1<sub>3</sub> correspond closely to their counterparts in V0C1<sub>3</sub> and Cr0<sub>2</sub>C1<sub>2</sub>, suggesting similar force fields in the three molecules. The infrared spectrum of the volatile products of the reaction between PC1<sub>3</sub> and NaN<sub>3</sub> indicates the presence of several molecules, possibly including C1<sub>2</sub>PN<sub>3</sub> and oligomers of C1<sub>2</sub> P = N, although no definite conclusions are drawn. Spectroscopic evidence also suggests that the reaction between (CH<sub>3</sub>)<sub>2</sub>PC1 and NaN<sub>3</sub> yields (CH<sub>3</sub>)<sub>2</sub>PN<sub>3</sub> as a major product, although observations such as the effect of ultraviolet photolysis remain unexplained.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:255371 |
| Date | January 1980 |
| Creators | Evans, Richard |
| Contributors | Downs, Anthony John |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://ora.ox.ac.uk/objects/uuid:f1490fe0-3b29-4036-bbdd-60d64ce15fcb |
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