The synthesis of a linear beryllium bis(diazaborolyl) compound featuring the first non-cluster bond between boron and beryllium has been achieved through the reaction of Yamashita's lithium diazaborolide and BeCl2. In accord with the established chemistry of beryllium, the bonding is polar covalent in character, as determined by structural and spectroscopic analysis, as well as reactivity studies.

Insertion of CO(2) into the metal-N bond of a series of synthetically important alkali-metal TMP (2,2,6,6-tetramethylpiperidide) complexes has been studied. Determined by X-ray crystallography, the molecular structure of the TMEDA-solvated Li derivative shows a central 8-membered (LiOCO)(2) ring lying in a chair conformation with distorted tetrahedral lithium centres. While trying to obtain cry...

PURPOSE To investigate the influence of cement film thickness, cement type, and substrate (enamel or dentin) on ceramic fracture resistance. MATERIALS AND METHODS One hundred extracted human third molars were polished to obtain 50 enamel and 50 dentin specimens. The specimens were cemented to 1-mm-thick lithium disilicate ceramic plates with different cement film thicknesses (100 and 300 μm) ...

The MM3 force field has been extended to deal with the lithium amide molecules that are widely used as efficient catalysts for stereoselective asymmetric synthesis. The MM3 force field parameters have been determined on the basis of the ab initio MP2/6-31G* and/or DFT (B3LYP/6-31G*, B3-PW91/6-31G*) geometry optimization calculations. To evaluate the electronic interactions specific to the lithi...

MP2 calculations with cc-pVTZ basis set were used to analyze intermolecular interactions in F3CX···YLi···NCCN and F3CX···NCCN···LiY triads (X = Cl, Br; Y = CN, NC) which are connected via halogen and lithium bonds. Those complexes with the role of LiY as halogen acceptor and lithium donor show cooperativity with energy values ranging between -1.97 and -2.92 kJ mol...

Structural diversity and a variety of bonding schemes emerge as characteristics of the Li-B phase diagram in this ground-state theoretical investigation. We studied stoichiometries ranging from LiB(15) to Li(5)B, over a pressure range from 1 atm to 300 GPa. At P = 1 atm, stability is found for the experimentally known LiB(0.8-1.0), LiB(3), and Li(3)B(14) phases. As the pressure rises, the latte...

One of the primary challenges faced by today’s dental restorative team is the need to deliver high-strength restorative options without compromising the esthetic outcome fueled by ever-increasing patient demands. The availability of improved ceramic materials, bonding techniques, new technology and issues of malgam safety have led to a revival of interest in ceramic inlays in dentistry over the...

Potential curves for the ground and the first lowest excited states of the MHe (where M={Li,Na,K,Rb,Cs,Fr}) exciplexes are calculated using the density functional theory (DFT) formalism. Relativistic calculations are carried out with and without spin-orbit (SO) coupling effect, using a zeroth order regular approximation (ZORA) approach. The depth De and position Re parameters of the potential c...

The water-coordinated Ni(2+) cation in the title compound, [Ni(C(10)H(5)N(3)O(4))(H(2)O)](n), assumes an octa-hedral NiN(3)O(3) coord-ination mode and is N,O-chelated by two deprotonated 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarb-oxy-lic acid (HPyImDC(2-)) ligands, forming a layer structure extending in the bc plane. The chains are arranged along the b-axis direction, forming a layer structure ex...