Synthesis, characterization, and biological relevance of hydroxypyrone andhydroxypyridinone complexes of molybdenum

We have prepared a number of complexes of the type cis-MoO2L2 where L repre sents a hydroxypyronato or hydroxypyridinonato ligand. Both the maltol (3-h ydroxy-2-methyl-4-pyrone, Hma) and kojic acid (5-hydroxy-2-hydsoxymethyl-4- pyrone, Hka) complexes, cis-MoO2(ma)(2) (1) and cis-MoO2(ka)(2) (2), have b een characterized by X-ray diffraction studies. The pyrone ligands are boun d to molybdenum in a cis bidentate fashion via the deprotonated hydroxyl gr oups and the ketone moieties. Crystals of 1 are orthorhombic, a = 12.107 (1 ), b = 8.6169 (8), c = 16.472 (1) Angstrom, Z = 4, space group Pca2(1), and those of 2 are monoclinic, a = 8.4591 (5), b = 16.3453 (10), c = 10.2954 ( 7) Angstrom, beta = 103.0320 (10)degrees, Z = 4, space group P2(1)/c. Hydro xypyridinone molybdenum complexes have been prepared for both maltol and ko jic acid derivatives with the substituents Me, n-Pr, CH2Ph, Ph at the ring nitrogen. Crystals of the 3-hydroxy-2-methyl-1-phenyl-4-pyridinone (Hppp) d erivative, MoO2(ppp)(2) (9), are monoclinic, a = 10.9476 (6), b = 13.5353 ( 9), c = 17.4877 (10) Angstrom, beta = 93.465 (4)degrees, Z = 4, space group P2(1)/n. Initial investigations into the effects molybdenum compounds have on diabetic hearts are presented. Both Na2MoO4 (used as a control) and 1 w ere effective in lowering blood glucose and free fatty acid levels. Diabeti c rats treated with molybdate showed significant improvements in postischem ic cardiac function.