The reactions of aminopodand (1) with trimer N3P3CI6 (2) and tetramer N4P4CI8 (3) in MeCN have been studied. Trimer gave two products. The bridged BINO P6N8CI10C18H22O4. H2O (4) and ANSA monocyclophosphaza-crown ether P3N5CI4C18H22O4 (5) were isolated. Tetramer gave ANSA C18H22O4P4N6CI6 (6) product The spectral data (IR, H-1, C-13, P-31 NMR and MS) are presented. The molecular structure of compound (4) was determined by X-ray diffraction techniques for further structural assignment. It contains one mole of water molecule, which results from strong intramolecular hydrogen bonding [N5-H ... O5 = 1.994(1) Angstrom]. It crystallizes in the monoclinic space group C2/c with a = 21.788(1), b = 7.883(1), c = 23.412(1) Angstrom, beta = 101.50(2)degrees, V = 3940.1(3) Angstrom(3), Z = 8 and D-x = 3.28 g cm(-3). (C) 1999 Elsevier Science B.V. All rights reserved.