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Amide and ester coupling reactions of ω-functionalized monolayer-protected gold cluster molecules (MPCs) are an exceptionally efficient avenue to a diverse variety of polyfunctionalized MPCs starting from a small subset of ω-functionalized materials. In this paper, coupling reactions have been employed to produce 13 MPCs bearing multiple copies of a diverse variety of structural groups. Detailed features of three of the 13 polyfunctionalized products are highlighted:  (a) stepwise coupling and deprotection reactions result in an MPC surrounded by ca. eight pendant tripeptides, (b) a preliminary Steady-State Electron Paramagnetic Resonance (SSEPR) experiment is described for MPCs bearing multiple spin labels (ca. 13/cluster), and (c) a polyelectron electrochemical reaction is described for an MPC bearing multiple (ca. 7/cluster) coupled phenothiazine derivatives. The coupling reactions substantially expand the available diversity of MPCs as polyfunctionalized chemical reagents platformed on a nanometer-sized central core.

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The syntheses and characterization of a series of complexes of the general formula [Cl(bpy‘)Ru(tppz)Ru(bpy‘)Cl](PF6)2, where tppz is tetra-2-pyridylpyrazine and bpy‘ is 2,2‘-bipyridine or substituted 2,2‘-bipyridine, are described. Preparations with 2,2‘-bipyridine or 4,4‘-dimethyl-2,2‘-bipyridine (1 and 2, respectively) give mixtures of two isomers. The isomers of 2 were separated chromatographically and the X-ray crystal structure of the cis isomer was solved. Significant distortion is observed in both the coordination geometry around each ruthenium atom and in the tppz ligand resulting in short intramolecular Ru···Ru and Cl···Cl separations (6.558(1) and 5.880(2) Å, respectively). Ligands containing two bipyridine groups linked through eight- and nine-atom bridges have also been synthesized. The length of the bridge between bipyridine groups allows for the formation of cis complexes 3−5 having the general formula shown above but prevents formation of a trans isomer.