Investigation of the structural properties of 2-naphthylamine substituted cyclotetraphosphazenes

In the present study, 2-naphthylamine substituted cyclotetraphosphazenes were synthesized and characterized for the first time. The reaction of octachlorocyclotetraphosphazene (1) with 2-naphthylamine (2) was performed in a THF solution and gave eight products (3-10). All the 2-naphthylamine substituted cyclotetraphosphazene compounds (3-10) were fully characterized by elemental analysis, MALDI-TOF mass spectrometry, H-1, C-13 and P-31 NMR spectroscopies. The molecular structure of the non-geminal bis-substituted 2-naphthylamine cyclotetraphosphazene compound 3 (2-trans-6) was also determined by X-ray crystallography. Compounds 3. 4 and 8 could be formed by an S(N)2 mechanism. Compounds 5-7, 9 and 10 might be formed by both S(N)1 and S(N)2 reaction mechanisms. These mechanisms were supported by P-31 NMR and X-ray crystallography results. (C) 2014 Elsevier Ltd. All rights reserved.