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JOURNAL OF CHEMICAL SCIENCES, vol.121, no.6, pp.989-1001, 2009 (SCI-Expanded)
Salicyclaldimines (5-9) and naphthaldimines (10-13) derived from condensation reactions of N(2)O(2) donor type bifunctional aminopodands (1-4), [(H(2)NPhO)(2)R, where R = CH(2)CH(2), CH(2)CH(2)CH(2) and CH(2)PhCH(2)], and hydrazine monohydrate with salicylaldehyde and 2-hydroxy-1-naphthaldehyde, respectively, have been prepared (scheme 1) and characterized by elemental analyses, UV-vis, FTIR, NMR and MS. NMR assignments were made using (1)H, (13)C NMR, DEPT and aided by 2D HETCOR and HMBC heteronuclear correlation techniques. The UV-vis spectra of the Schiff bases have been systematically studied in organic solvents of different polarity, acidic and basic media and found useful in understanding of tautomeric equilibria (phenol-imine, O-HaEuro broken vertical bar N and keto-amine, OaEuro broken vertical bar H-N forms) in this series. The molecular structure of 8 has been determined crystallographically, and observed that the compound is in the form of phenol-imine, defined by the strong intramolecular [O-HaEuro broken vertical bar N = 1 center dot 72(3), 1 center dot 81(2) ] hydrogen bonds. Compound 8 crystallizes in the monoclinic space group P2(1)/a with a = 8 center dot 4675(7), b = 38 center dot 448(3), c = 9 center dot 3875(7) , beta = 103 center dot 0780(10)A degrees, V = 2976 center dot 9(4) (3), Z = 4 and D (x) = 1 center dot 271 Mg m(-3), and contains acetonitrile molecule in the crystal lattice.