| Organic Derivatives of Heteropoly Molybdates. |
NOV 1976 |
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| Authors:
Michael T. Pope; Carl O. Quicksall; Wonsuk Kwak; L. M. Rajdovic; Judith K. Stalick; GEORGETOWN UNIV WASHINGTON D C DEPT OF CHEMISTRY
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 | Heteropoly molybdate(VI) and tungstate(VI) anions are typically ionic oxometallate clusters of high symmetry, large size, and high ionic weight. They are usually the anions of strong acids, they form salts that are soluble in a variety of aqueous and nonaqueous solvents, and they may also undergo a series of reversible electron transfer reactions to yield mixed valence (V, VI) heteropoly blues. It has been customary to represent the structures of ... |
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| Pentamolybdobis (cis-phosphatobisethylenediamineaquocobalt(III). A 'Neutral' Heteropoly Complex. |
NOV 1976 |
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| Authors:
Wonsuk Kwak; Michael T. Pope; GEORGETOWN UNIV WASHINGTON D C DEPT OF CHEMISTRY
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| The synthesis, optical and infrared spectra of the title compound, (co(en)2(H2O)OPO352Mo5O15) are described. The complex is an electrically neutral zwitterion. (Author) |
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| Stable Organic Derivatives of Heteropoly Anions, Pentamolybdobisphosphonates. |
MAY 1975 |
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| Authors:
Wonsuk Kwak; Michael T. Pope; Thomas F. Scully; GEORGETOWN UNIV WASHINGTON D C DEPT OF CHEMISTRY
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| Heteropoly molybdates containing covalently bound organic moieties have been prepared and characterized by chemical analysis and spectroscopic measurements. Salts of the anions (RP)2Mo5O21(4-), where R = H, CH3, C2H5, C6H5, C2H4NH3(+) and pCH2C6H4NH3(+), are stable in aqueous solution at pH 2.5 - 5. The new complexes have a structure related to that of P2Mo5O23(6-) and are not reducible to heteropoly blue species. The amino derivatives are the first examples of ... |
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| A New Type of Heteropoly Anion. Tetramolybdo Complexes of Dialkyl- and Diaryl Arsinates. |
MAY 1975 |
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| Authors:
Kathleen M. Barkigia; Ljudmila Rajkovic; Michael T. Pope; Carl O. Quicksall; GEORGETOWN UNIV WASHINGTON D C DEPT OF CHEMISTRY
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| Synthesis and characterization of several salts of the heteropoly complexes (R2AsMo4O14(OH))(2-), R = CH3, C2H5, C6H5, are described. These are some of the first examples of stable organic derivatives of heteropoly anions. The crystal structure of (CN3H6)2((CH3)2AsMo4O14(OH))-H2O shows the anion to consist of a compact cluster of edge- and face-shared MoO6 octahedra capped by the (CH3)2AsO2 tetrahedron. The new complexes have two other unusual features. First, a uniquely low charge ... |
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| Studies of the Properties of Selected Chemical Compounds for Preparation of New Materials. |
AUG 1974 |
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| Authors:
Michael T. Pope; GEORGETOWN UNIV WASHINGTON D C DEPT OF CHEMISTRY
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| Synthesis and characterization of new heteropoly complexes containing Re(V), Re(VI), Re(VII), OsN(3+), RuNO(3+), RuNO(2+), U(V) and Ce(III) are reported. Rapid reversible electron transfer between isostructural pairs of heteropoly complexes has been studied. Optical and ESR spectroscopy of mixed valence polyanions (heteropoly blues) have shown that such compounds contain electrons that are delocalized over several metal atoms by a thermally activated hopping process. Heteropoly blues are therefore molecular analogs of semiconducting ... |
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| HETEROPOLY COMPOUNDS OF VB ELEMENTS. |
31 MAY 1970 |
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| Authors:
Michael T. Pope; GEORGETOWN UNIV WASHINGTON D C DEPT OF CHEMISTRY
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| The report reviews the chemistry of isopoly anions of vanadium, niobium and tantalum, and describes the preparation and properties of fifteen heteropolyanions of these elements. No discrete heteropoly niobates and tantalates have previously been reported. Several new complexes of manganese and nickel in the rare +4 oxidation state are described. Mixed-valence heteropoly anions containing vanadium are reported for the first time. Optical and esr spectroscopy of these species are used ... |
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| PROPERTIES AND STRUCTURES OF HETEROPOLY BLUES. |
13 MAY 1967 |
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| Authors:
Michael T. Pope; GEORGETOWN UNIV WASHINGTON D C DEPT OF CHEMISTRY
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| The work established that heteropoly blues are discrete anionic species, almost certainly isostructural with the oxidized anions. Heteropoly tungstates can be reduced in one-electron steps and the corresponding molybdates only in two-electron steps, a difference for which there is no immediately obvious explanation. Addition of electrons markedly affects the stability of the heteropoly structures, which become increasingly inert towards alkaline degradation upon reduction. (Author) |
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