On the way to sol-gels: an analysis of the intra- and intermolecular hydrogen bonding in

We have been able, via a new synthetic route, to obtain a complete crystal structure of the title compound, tetraaquabarium hydroxide iodide, [Ba(OH)I(H(2)O)(4)], for which the heavy atoms only were characterized by Kellersohn, Beckenkamp & Lutz [Z. Naturforsch. Teil B (1991), 46, 1279-1286]. In the present results, the H-atom positions could be located using X-ray data collection at low temperature. A three-dimensional network is built up via hydrogen bonds. It was also observed that the title compound undergoes hydrolysis and might therefore be regarded as an intermediate in the formation of sol-gels, starting from BaI(2) and leading to [Ba(OH)(2)(H(2)O)(x)].

Multiple expression of molecular information: enforced generation of different supramolecular inorganic architectures by processing of the same ligand information through specific coordination algorithms

The multisubunit ligand 2 combines two complexation substructures known to undergo, with specific metal ions, distinct self-assembly processes to form a double-helical and a grid-type structure, respectively. The binding information contained in this molecular strand may be expected to generate, in a strictly predetermined and univocal fashion, two different, well-defined output inorganic architectures depending on the set of metal ions, that is, on the coordination algorithm used. Indeed, as predicted, the self-assembly of 2 with eight CuII and four CuI yields the intertwined structure D1. It results from a crossover of the two assembly subprograms and has been fully characterized by crystal structure determination. On the other hand, when the instructions of strand 2 are read out with a set of eight CuI and four MII (M = Fe, Co, Ni, Cu) ions, the architectures C1-C4, resulting from a linear combination of the two subprograms, are obtained, as indicated by the available physico-chemical and spectral data. Redox interconversion of D1 and C4 has been achieved. These results indicate that the same molecular information may yield different output structures depending on how it is processed, that is, depending on the interactional (coordination) algorithm used to read it. They have wide implications for the design and implementation of programmed chemical systems, pointing towards multiprocessing capacity, in a one code/ several outputs scheme, of potential significance for molecular computation processes and possibly even with respect to information processing in biology.