ja057548w_si_002.pdf (614.4 kB)

Dendritic Arrays of [Re63-Se)8]2+ Core-Containing Clusters:  Exploratory Synthesis and Electrochemical Studies

Download (614.4 kB)
journal contribution
posted on 24.05.2006 by Bryan K. Roland, Ware H. Flora, Hugh D. Selby, Neal R. Armstrong, Zhiping Zheng
The reaction between the previously reported site-differentiated cluster solvate [Re63-Se)8(PEt3)5(MeCN)](SbF6)2 (1) with pyridyl-based ditopic ligands 4,4‘-trimethylenedipyridine (2), 1,2-bis(4-pyridyl)ethane (3), and (E)-1,2-bis(4-pyridyl)ethene (4) afforded cluster complexes of the general formula [Re63-Se)8(PEt3)5(L)](SbF6)2 (57), where L represents one of the pyridyl-based ligands. Reacting these cluster complex-based ligands with the fully solvated cluster complex [Re63-Se)8(MeCN)6](SbF6)2 (8) produced dendritic arrays of the general formula {Re63-Se)8[Re63-Se)8(PEt3)5(L)]6}(SbF6)14 (911), each featuring six circumjacent [Re63-Se)8(PEt3)5]2+ units bridged to a [Re63-Se)8]2+ core cluster by the pyridyl-based ligands. Electrochemical studies using a thin-layer electrochemical cell revealed cluster-based redox events in these cluster arrays. For 9 (L = 2), one reversible oxidation event corresponding to the removal of 7 electrons was observed, indicating noninteraction or extremely weak interactions between the clusters. For 10 (L = 3), two poorly resolved oxidation waves were found. For 11 (L = 4), two reversible oxidation events, corresponding respectively to the removal of 1 and 6 electrons, were observed with the 1-electron oxidation event occurring at a potential 150 mV more positive than the 6-electron oxidation. These electrochemical studies suggest intercluster coupling in 11 via through-bond electronic delocalization, which is consistent with electronic spectroscopic studies of this same molecule.

History

Exports