Synthesis and characterization of tantalum silsesquioxane complexes.

Tantalum polyhedral oligosilsesquioxane (POSS) complexes have been synthesised and characterized. X-ray structures of these complexes revealed that the coordination number of the tantalum center greatly affects the cube-like silsesquioxane framework.

Synthesis and reactivity of cationic ruthenium germylene complexes [Cp*(PiPr3)RuH2(=GeRR')]+.

Two synthetic routes to cationic ruthenium germylene complexes are described. A hydrogen-substituted germylene complex undergoes various additions of the Ge-H bond to alkene and alkyne substrates.

Cocrystal or salt: does it really matter?

A structural analysis of over 80 salts and cocrystals synthesized from equimolar amounts of carboxylic acids and N-heterocycles demonstrates that salt formation as a result of proton transfer from the acid to the base frequently (11/24; 45%) results in a lattice with an unpredictable chemical (solvate) or stoichiometric composition. However, if no proton transfer takes place and the result is a molecular cocrystal, a crystal lattice with an unexpected chemical content or stoichiometry is much less likely (3/61; 5%). These results indicate that the process of converting a neutral carboxylic acid into a carboxylate anion can have important structural consequences that make structure prediction and targeted supramolecular synthesis of salts much more difficult than of cocrystals.