The conductance of molecular junctions, formed by breaking gold point contacts dressed with various thiol functionalized organic molecules, is measured at 293 K and at 30 K. In the presence of molecules, individual conductance traces measured as a function of increasing gold electrode displacement show clear steps below the quantum conductance steps of the gold contact. These steps are distributed over a wide range of molecule-dependent conductance values. Histograms constructed from all conductance traces therefore do not show clear peaks either at room or low temperatures. Filtering of the data sets by an objective automated procedure only marginally improves the visibility of such features. We conclude that the geometrical junction to junction variations dominate the conductance measurements.

5 9b) (derived from 5), respectively, exhibit more complex behaviour. These observations contrast with those from the previously published benzyl congener [Zr(η-C 5 H 4 CH 2 Ph) 2 Me 2 ] 1 which, with methyl abstracting agent, generates both a solvent separated cation/anion pair and a tight ion pair.

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Three paramagnetic heterobimetallic lantern complexes of the form [PtM(tba) 4 (OH 2 )] (M ¼ Fe, 1; Co, 2; Ni, 3; tba ¼ thiobenzoate) have been prepared in a single-step, bench-top procedure. In all three cases, a lantern structure with Pt-M bonding is observed in solution and in the solid state. Compound 1 is a monomer whereas 3 exists as a dimer in the solid state via a Pt/Pt metallophilic interaction. Compound 2 has been characterized in forms with (2a, purple) and without (2b, yellow) Pt/Pt metallophilic interactions. The dimers 2a (J ¼ À10 cm À1 , based on the spin Hamiltonian Ĥ ¼ À2J (S A $S B )) and 3 (J ¼ À60 cm À1 ) exhibit antiferromagnetic coupling between the two first-row metal ions in the solid state via a Pt/Pt non-covalent metallophilic interaction. The electronic structure ofNi, units have been studied with DFT calculations, confirming the relative spin-state energies observed and the antiferromagnetic exchange pathway through four d z 2 orbitals. The compounds 2a and 3 are the first examples of antiferromagnetic coupling through an unbridged M/M contact.