Crystal structure of 15,21-bis(diethoxyphosphinoyl)-2,5,8-trioxa-16,20-diazatricyclo-[20.4.0.0(9,14)] hexacosa-9,11,13,22,24,26(1)-hexaene-ethylphosphonic acid-water (1/1/1)

The title compound (C31H55N2O13P3) crystallizes in the triclinic space grou p P (1) over bar with a=12.676(4) Angstrom, b=13.733(3)Angstrom, c=14.042(2 )Angstrom, alpha =67.94(4)degrees, beta =77.15(4)degrees, gamma =61.95(4)de grees, V=1996.2(8)Angstrom (3), Z=2, D-x=1.259 g.cm(-3). The structure was solved by direct methods and refined by full-matrix least-squares method (R =0.055). The macrocyclic ligand is an 18-membered lariat ether containing t wo N and three etheral O atoms and two phosphonate side groups. The title c ompound consists of the macrocyclic ligand, one ethyl phosphonic acid and o ne water molecule, as a whole. In the macrocyclic ring, the mean N . . .O d istance is 5.481(6) Angstrom. The relative macrocyclic inner hole size, est imated as twice the mean distance of the donor atoms from their centroid is approximately 2.29 Angstrom.