Crystal and molecular structure of (+ )-(S,S′)-α,α′-(9-OXO-1,5-diphenyl-3,7-diazabicyclo[3.3.1]non-3,7-ylene)dipropionic acid

The crystal and molecular structure of ( + )-(S,S′ )-α,α′-(9-oxo-1,5-diphenyl-3,7-diazabicyclo[3.3.]]non-3,7-ylene)diprvpionic acid (I) was determined by X-ray diffraction: space group P21]2121, a = 11.277(1), b = 17.810(2), c = 21.865(2) Å, Z = 8(C25H28N2O5)-The structure of 1 was solved by direct methods and refined by the full-matrix least-squares procedure in an anisotropic approximation to R = 0.044 for 3655 independent reflections (CAD-4 automatic diffractometer, λCuKα. The structure contains two symmetrically independent molecules existing in zwitterionic form (with one pmtonated N atom) and having similar geometrical parameters of the bicyclic frameworks and different orientations (conformations) of their acid substituents. In both molecules, the bicyclic framework consists of two fused six-membered rings and has a chair-chair conformation stabilized by the intramolecular H-bond N-H...N. The carboxyl H atoms of both independent molecules are involved in strong intermolecular H-bonds O-H...O, some of which are nearly symmetrical