Tetrameric arrays of the [Re6(μ3-Se)8]2+ clusters supported by a porphyrin core: synthesis, characterization, and electrochemical studies

Abstract A tetracluster array {[Re 6 ( μ 3 -Se) 8 (PEt 3 ) 5 ] 4 [5,10,15,20-tetra(4-pyridyl)-21 H ,23 H -porphine]}(SbF 6 ) 8 ( R 4 ) featuring a central porphyrin core and four circumjacent [Re 6 ( μ 3 -Se) 8 ] 2+ units was synthesized by reacting the previously reported cluster solvate [Re 6 ( μ 3 -Se) 8 (PEt 3 ) 5 (MeCN)](SbF 6 ) 2 ( R ) with 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine. Metallation of R 4 with metal (Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ ) salts afforded the corresponding cluster-studded metalloporphyrins ( R 4 – Co , R 4 – Ni , R 4 – Cu , and R 4 – Zn ). All compounds were characterized by 1 H and 31 P NMR spectroscopy and elemental analysis (CHN). Electrochemical studies revealed one chemically reversible oxidation event attributable to the simultaneous removal of four electrons, one from each of the four cluster units. The uncoupled redox event suggests minimal electrical communication between the cluster sites. The cluster arrays were also studied by UV–vis spectroscopy. The electronic spectra of R 4 – Co , R 4 – Ni , and R 4 – Cu each showed the absorptions of the metalloporphyrins and the cluster complex. For R 4 – Zn , solvatochromism was observed. Its electronic absorptions in a variety of solvents of different dielectric constants were studied. To cite this article: B.K. Roland et al., C. R. Chimie 8 (2005) .

[1]  Zhiping Zheng,et al.  Synthesis and Structures of Solvated Monoclusters and Bridged Di- and Triclusters Based on the Cubic Building Block [Re(6)(&mgr;(3)-Se)(8)](2+). , 1999, Inorganic chemistry.

[2]  J. Gabriel,et al.  Chemistry of hexanuclear rhenium chalcohalide clusters. , 2001, Chemical reviews.

[3]  J. Long,et al.  Atomlike Building Units of Adjustable Character: Solid‐State and Solution Routes to Manipulating Hexanuclear Transition Metal Chalcohalide Clusters , 2005 .

[4]  Jeffrey R. Long,et al.  A Basis Set of Re6Se8 Cluster Building Blocks and Demonstration of Their Linking Capability: Directed Synthesis of an Re12Se16 Dicluster , 1997 .

[5]  Martin Gouterman,et al.  Spectra of porphyrins: Part II. Four orbital model , 1963 .

[6]  Allen J. Bard,et al.  Electrochemical Methods: Fundamentals and Applications , 1980 .

[7]  R. Drago,et al.  AN E AND C ANALYSIS OF DONOR NUMBERS AND SORET BAND SHIFTS IN ADDUCTS OF ZINC TETRAPHENYLPORPHINE , 1981 .

[8]  Taro Saito.  Rhenium sulfide cluster chemistry , 1999 .

[9]  R. Arratia-Pérez,et al.  The Re6Se8Cl64− and Re6Se8I64− cluster ions: Another example of luminescent clusters? , 1999 .

[10]  J. Long,et al.  A Solid-State Route to Molecular Clusters: Access to the Solution Chemistry of [Re6Q8]2+ (Q = S, Se) Core-Containing Clusters via Dimensional Reduction , 1996 .

[11]  N. Kitamura,et al.  Chelate Formation around a Hexarhenium Cluster Core by the Diphosphane Ligand Ph2 P(CH2 )6 PPh2. , 2001, Angewandte Chemie.

[12]  Zhiping Zheng,et al.  Ligand-bridged oligomeric and supramolecular arrays of the hexanuclear rhenium selenide clusters--exploratory synthesis, structural characterization, and property investigation. , 2003, Accounts of chemical research.

[13]  M. Carducci,et al.  Built to order: molecular tinkertoys from the [Re(6)(mu(3)-Se)(8)](2+) clusters. , 2002, Journal of the American Chemical Society.

[14]  Abhik Ghosh,et al.  Electrochemistry of Nickel and Copper β-Octahalogeno-meso-tetraarylporphyrins. Evidence for Important Role Played by Saddling-Induced Metal(dx2-y2)−Porphyrin(“a2u”) Orbital Interactions , 2001 .

[15]  V. Gutmann.  Empirical approach to ligand effects on the kinetics of substitution and redox reactions , 1974 .

[16]  Thomas G. Gray.  Hexanuclear and higher nuclearity clusters of the Groups 4–7 metals with stabilizing π-donor ligands , 2003 .

[17]  O. W. Kolling.  Soret red shift for zinc tetraphenylporphine in the presence of uncharged Lewis bases , 1979 .

[18]  R. Drago.  The interpretation of reactivity in chemical and biological systems with the E and C model , 1980 .

[19]  D. Nocera,et al.  Spectroscopic and photophysical properties of hexanuclear rhenium(III) chalcogenide clusters. , 2003, Journal of the American Chemical Society.

[20]  Mario Joseph Nappa,et al.  The influence of axial ligands on metalloporphyrin visible absorption spectra. Complexes of tetraphenylporphinatozinc , 1978 .