Synthesis, characterization, and reactivity of group 13 hydride complexes based on amido-amine ligands.

The preparation of group 13 hydride complexes supported by N,N',N'-substituted 1,2-ethanediamines is reported. Dihydridoalanes LAlH2, for which the aggregation behaviour in solution and in the solid state is modulated by the steric bulk of the aryl substituent, readily react with elemental sulphur affording dinuclear aluminium sulphide complexes. Chloridohydrido trielanes LEHCl (E = B, Al, Ga) have been synthesized as well starting from the hydrochloride salts of the protio-ligands and the chlorido substituent within LAlHCl is readily replaced using Li[N(SiMe3)2].

Nucleophilic Magnesium Silanide and Silaamidinate Derivatives.

Density functional theory (DFT) calculations demonstrate that the previously reported reaction of [(BDI)Mg--Bu] (BDI = HC{(Me)CN-Dipp}; Dipp = 2,6-diisopropylphenyl) with the silaborane MePhSi-Bpin provides the magnesium silanide derivative [(BDI)MgSiMePh], through the intermediacy of a short-lived silyl-pinacolato-organoborate species. The nucleophilic character of the resultant silanide anion is assayed through a series of reactions with RN═C═NR (R = i-Pr, Cy, -Bu) and -tolN═C═N--tol. When they are performed in a strict 1:1 stoichiometry, all four reactions result in silyl addition to the carbodiimide carbon center and formation of the corresponding β-diketiminato magnesium silaamidinate complexes.

Synthesis and Coordination Chemistry of 3,4-Ethylene-Bridged 1,1,2,5-Tetrasubstituted Biguanides.

The synthesis of 3,4-ethylene-bridged 1,1,2,5-tetrasubstituted biguanides is reported, which are accessible by three alternative routes. Exemplary molecular structures of the ligand and an observed side product have been elucidated by X-ray diffraction analysis. Mono- and dinuclear complexes of the biguanide in both its neutral and monoanionic forms were obtained, including examples of aluminum, copper, magnesium, potassium, tin, and zinc, indicating a versatile coordination behavior, as evidenced by means of single-crystal X-ray diffraction analysis.

Novel Mutation in the DKC1 Gene: Neonatal Hoyeraal-Hreidarsson Syndrome As a Rare Differential Diagnosis in Pontocerebellar Hypoplasia, Primary Microcephaly, and Progressive Bone Marrow Failure.

Primary microcephaly and severe developmental delay are complex but unspecific signs pointing to various genetic or acquired diseases. A concomitant finding of hematological failure may lead to the differential diagnosis of rare genetic diseases such as chromosome breakage disorders or diseases associated with telomere dysfunction. X-linked Hoyeraal-Hreidarsson syndrome (HHS) is a rare heterogenic disorder characterized by severe neurological impairment and progressive bone marrow failure.