We present auxilliary basis sets for the atoms H to At ± excluding the Lanthanides ± optimized for an ecient treatment of molecular electronic Coulomb interactions. For atoms beyond Kr our approach is based on eective core potentials to describe core electrons. The approximate representation of the electron density in terms of the auxilliary basis has virtually no eect on computed structures and aects the energy by less than 10 À4 a.u. per atom. Eciency is demonstrated in applications for molecules with up to 300 atoms and 2500 basis functions.

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The metal‐binding sites of sucrose have been revealed for the first time by reaction with an aqueous solution of [Pd(en)(OH)2] (Pd‐en). The structure of the resulting complex is depicted on the right. Pd‐en is also a coordinating solvent for cellulose and gives rise to molecularly dispersed polysaccharide chains that act as poly‐diolato ligands. The metallated cellulose chain is stiffened by strong intramolecular, interresidue hydrogen bonding.

An extensive ab initio study of the structures, vibrational spectra, quadratic force fields, and relative energetics of three isomers of Cl2O2Results of a systematic theoretical study of stoichiometric clusters Mg n Cl 2n up to nϭ24 are reported within the self-consistent-field ͑SCF͒ approximation. Calculations within second-order Mo "ller-Plesset perturbation theory and single-and double-excitation coupled cluster method with a perturbational estimate of triples excitations are performed for the smaller clusters to check accuracies. The clusters Mg n Cl 2n do not show a consistent preference for geometries which are fragments of the bulk lattice as it is known for the alkali halide systems: Small clusters Mg n Cl 2n prefer linear chain structures corresponding to the SiS 2 crystal lattice, the most stable medium sized clusters ͑5рnϽ20͒ are high-symmetry ''cyclic'' SiS 2 structures, and only for large systems ͑nу20͒ we realize a transition to the magnesium chloride lattice structure. The computed binding energies of the larger clusters allow for an extrapolation of the lattice energy which is in good agreement with experiment.

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