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Vitamin D is an essential hormone for calcium gut absorption. It is also involved in child growth, cancer prevention, immune system responses, and tooth formation. Due to inadequate vitamin D intake and/or decreased sunlight exposure, vitamin D deficiency has resurfaced in developed countries despite known inexpensive and effective preventive methods. Vitamin D deficiency is a common cause of rickets, a condition that affects bone development in children and that can have serious dental complications. Deficiency during pregnancy can cause enamel hypoplasia of primary teeth. Enamel regeneration is currently impossible; hypoplasia is therefore irreversible, and once affected, teeth are prone to fast caries development. Deficiency during early childhood can affect permanent teeth and ensuing caries can sometimes lead to tooth loss at a young age. Oral manifestations of rickets should be diagnosed early by both physicians and dentists to prevent severe dental complications. This case study presents 2 young girls with rickets in early childhood who suffered from subsequent serious tooth decay.

New complexes of the formula (Cp'Mo^-S^SsCHR, where R = C02Me (3) and C02Na (4) (Cp' = C5H5, CH3C5H4), have been synthesized and characterized spectroscopically. Their reactions have been compared to those of the parent compound, where R =(1). The synthesis of 3 involved the alkylation of (MeCpMo)2U-S2) (µ-Sh with BrCH2C02Me to form [(MeCpMo)2-(µ-82)(µ-S)(g-SCH2C02Me)]Br (2(Br)). Complex 2 crystallized in space group P2Jc with a = 10.379(2) A, b = 20.820(6) A, c = 9.597(2) A, ß = 102.56°, V = 2024.3(8) A3, and Z = 4. An X-ray diffraction study of 2 confirmed that a µ-sulfido ligand was the site of alkylation and the µ-2 ligand remained intact. Complex 2 was deprotonated on an alumina column to form 3. The water-soluble complex 4 was synthesized by the reaction of [ , (µ-8)(µ-8 )]2 with Br2-CHC02Na in the presence of base. The reactivities of 3 and 4 are similar to that of 1 in most cases. Unlike 1, complex 3 reacts with triflic acid to cleave a C-S bond of the dithiolate ligand and form the triflate salt of 2. Complex 4 differs from 1 in that it undergoes an observable reaction with hydrogen in neutral or basic aqueous solution. Spectroscopic data for the hydrogen addition product are consistent with the formulation ( )2(µ-8)2(µ-8 )(µ-80 2 2 8) ( 7).The catalytic activity of 4 and 7 for D2-H20 exchange and for the hydrogenation of C=N and N=N bonds in two-phase aqueous/organic solvent systems has been studied.(µ-8))282 with new electron-withdrawing substituents on the methanedithiolate ligands and the characterization of their reaction chemistry. A second paper in this series describes the syntheses of water-soluble molybdenum sulfide complexes with electron-withdrawing substituents on the cyclopentadienyl ligands.15

The photochemistry of five 1,3-dicarbonyl compounds, substituted at the 1-position with an o-methylphenyl group, has been investigated. Compounds 5a-c cyclize upon irradiation to give tetralones 6a and 6c and octahydroanthracene derivative 6b, respectively. Compounds 5d and 5e do not form similar photoproducts. Diketone 5c is the most efficient in this reaction, indicating that the reaction probably occurs via the keto tautomer. A mechanism involving initial y-hydrogen abstraction followed by interception of the resulting 1,Cbiradical by the second carbonyl group is proposed.