Alejandro Guijarro

Electrical conductivity in platinum-dimer columns.

Three new compounds of formula [Pt2(SSCR)4] (R = CH3, (CH2)4CH3, cyclohexyl) have been prepared and characterized by X-ray diffraction. Their crystal structures consist of one-dimensional linear chains formed by stacking of the dimetallic complexes in which the alkyl group on the dithioacetate modulates the intermetallic distances between dimetallic entities. Direct current electrical conductivity studies show that crystals of the three compounds behave as semiconductors and their conductivity values are directly connected to the intermolecular metal-to-metal distances. These experimental results are supported by density functional theory calculations.

Nanofibers generated by self-assembly on surfaces of bimetallic building blocks

Adsorption on surfaces of diluted CH2Cl2 solutions of [Pt2(dta)4] (dta = dithioacetate) at room temperature does not lead to any organization. However, sonication or low temperature experiments results in the formation of 1D nanofibers on graphite.

Nuclearity control in gold dithiocarboxylato compounds

The reaction between ipdt (ipdt = −S2CCH2CH(CH3)2) and KAu(CN)2 in ethanol gives rise to crystals of compound 1 in which two different entities are present: the dimetallic complex [Au2(ipdt)2] and the coordination polymer [Au2(ipdt)2]n. The infinite structure of the polymeric entity, [Au2(ipdt)2]n, is sustained by means of bridging dithiocarboxylato ligands. When 1 is dissolved in CS2, the ditiocarboxylato ligands of [Au2(ipdt)2]n are rearranged to afford the discrete complex [Au2(ipdt)2], which undergoes aggregation in solution at a low temperature and high concentration. The X-ray structure of [Au2(ipdt)2] suggests that the driving force of the aggregation observed in solution can be explained in terms of intermolecular aurophilic interactions.

Supramolecular Assembly of Diplatinum Species through Weak PtII⋅⋅⋅PtII Intermolecular Interactions: A Combined Experimental and Computational Study

The present study elucidates the factors that govern the spontaneous self-assembly of a family of dimetal [Pt(2)L(4)] (L=dithiocarboxylato ligand) complexes. Experimental data show that variables such as temperature, concentration, solvent and the nature of the ligand L have a critical effect on the reversible self-assembly of supramolecular [Pt(2)L(4)](n) entities. In solution, new UV/Vis spectroscopic features emerge at low temperatures and/or high concentrations, which are attributed to the formation of oligomeric [Pt(2)L(4)](n) species. The description of intermolecular Pt⋅⋅⋅Pt interactions, the main driving force for the association, was addressed from a computational perspective. The contributions from intermolecular Pt⋅⋅⋅S and S⋅⋅⋅S interactions to these supramolecular assemblies were found to be repulsive. Experimental UV/Vis data have been interpreted by means of computational spectroscopy.