BORON COORDINATION COMPOUNDS WITH HYDROXYCARBOXILIC ACIDS. J. Schwartz, I. Zviedre, Institute of Inorganic Chemistry, Latvian Academy of Sciences, Latvia

The dependence of some properties of coordination compounds of boron, for example, the solubility in water (25deg.C), IR-spectra, on structural type of boron-oxygen polyhedron, size of heterocycle, the nature of cation and hydrogen bonds, is shown on the examples of 8 crystal and moleculare structures of the salts of DL-malato- (I); citrato- (II); salicylato- (III); p-aminosalicylatoI (IV); tartrato- (V,VI); xylotrihydroxyglutarato- (VII,VIII) borates.

I - K[(HOOCCH₂CHCOCOO)₂B] H₂O,

II - K[((HOOCCH₂)₂HCOCOO)₂B]^.2H_2O,

III - [Zn(H₂O)₄][(C₆H₄OCOO)₂B].4H₂O,

IV - K[(p-NH₂C₆H₃OCOO)₂B]^.H2O,

V - NH₄Sr[(OOCHCOHCOCOO)B(OH)₂]^.4H₂O,

VI -Na₅[(OOCHCOHCOCOO)₂B]^.5H₂O,

VII -NH₄Sr₂[(OOCHCOHHCOHCOCOO)₂B]^.4HO,

VIII -(NH₄)₂[Zn₂(H₂O)₂(OOCHCOHOHHCOCOO)(HO)B-O-B(OH) (OOCHCOHCOHHCOCOO)]^.4H₂O.

The authors synthesized I - VIII and determined the structures of I - V, VII - VIII by X-ray analysis. The solubility depends on the nature of the cation, on the size of boron heterocycle, on the existence of some lyophilic OH-groups in the ligand, on the hydrogen bonds system. For example, the great solubility of VII, which firstly was redarded as Zn-salt, could be explaned only after the determination ot the crystal structure, which showed, that VII is the ammonium salt, but Zn enters in the inner coordination sphere. Most potassium salts of the ligands with six-membered B-heterocycle are insoluble or little soluble in water, but - with five membered one - very well soluble.

The correlation of IR-absorption spectra and crystal structure is made.