SODIUM-HYDROGEN DIPICOLINATE DIPICOLINIC ACID TRIHYDRATE - SYNTHESIS,STRUCTURE, AND VALENCE-BOND SUMS

The synthesis and crystal structure of sodium hydrogen dipicolinate di picolinic acid trihydrate, NaHdipic . H(2)dipic . 3H(2)O, I, is report ed. There is a hydrogen bonded H-3(dipic)(2)(-) unit in which an Hdipi c(-) ion functions as a tridentate chelate to the Na+ ion while the se cond H(2)dipic functions as a monodentate ligand and bridging unit. Th e Na+ ion is in the center of a pentagonal bipyramid with two water mo lecules in the axial positions. The equatorial plane is composed of an Hdipic(-) ion, a water molecule and an oxygen from the H(2)dipic. An analysis of data in the Cambridge Structural Database for Na+ compound s using Valence Bond Sums has produced new r(o) values of 1.743 for Na -O and 1.891 for Na-N.