No abstract

An additional azidomethyl group dramatically decreases the melting points of the corresponding azidopyrimidines. Theoretical calculations show that these polyazido compounds (see picture; N light blue, C dark blue, H white) exhibit highly promising energetic properties. 2,4,6‐Triazidopyrimidine was found to be a novel precursor to carbon nanotubes in the presence of Ni(ClO4)2.

Dipyridylquinoxaline (dpq), 4-cyanopyridine (4-CNpy), 4,4Ј-bipyridine (4,4Ј-bpy) and quinoxaline form n→ * charge-transfer complexes with iodine (I 2 ), in which the N ؒ ؒ ؒ I distance [2.532(3) Å for dpqؒI 2 ; 2.543(9) and 2.555(9) Å for 4-CNpyؒI 2 ; 2.406(7) Å for 4,4Ј-bpyؒ2I 2 ; 2.92(1) and 2.95(1) Å for quinoxؒI 2 ] is shorter than the sum of the van der Waals radii for nitrogen (1.55 Å) and iodine (1.98 Å). Donation of electron density into the antibonding orbital of iodine weakens the I᎐I bond resulting in elongation relative to the value observed in elemental iodine (2.715 Å). Dpq, 4-CNpy and 4,4Ј-bpy form molecular adducts, while quinoxaline forms a polymeric species in which there are interactions at both ends of the I 2 molecule. The type of complex which forms depends on the nucleophilic character of the donor (and its corresponding effect of the I 2 molecule) and on the lattice energy of the complex. The strength of the N ؒ ؒ ؒ I interaction in each of the reported complexes has been investigated by X-ray crystallographic analysis and vibrational spectroscopy (far-IR). All of the complexes undergo thermal decomposition involving loss of I 2 , and their lattice energy, as a function of thermal stability, has been explored.

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