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Presents the synthesis, structure and physical properties of the series of molecular magnets formulated as [Z[sup II](bpy)[sub 3]][ClO[sub 4]][M[sup II]Cr[sup III](ox)[sub 3]] (Z[sup II] = Ru, Fe, Co, and Ni; M[sup II] = Mn, Fe, Co, Ni, Cu and Zn, ox = oxalate dianion). Magnetic properties; Structures.

A homologous series of dinuclear compounds with the bridging ligand 2-(2-pyridyl)-1,8-naphthyridine (pynp) has been prepared and characterized by X-ray crystallographic and spectroscopic methods. [Mo2(O2CCH3)2(pynp)2][BF4]2·3CH3CN (1) crystallizes in the monoclinic space group P21/c with a = 15.134(5) Å, b = 14.301(6) Å, c = 19.990(6) Å, # = 108.06(2)°, V = 4113(3) ų, and Z = 4. [Ru2(O2CCH3)2(pynp)2][PF6]2·2CH3OH (2) crystallizes in the monoclinic space group C2/c with a = 14.2228(7) Å, b = 20.3204(9) Å, c = 14.1022(7) Å, # = 95.144(1)°, V = 4059.3(3) ų, and Z = 4. [Rh2(O2CCH3)2(pynp)2][BF4]2·C7H8 (3) crystallizes in the monoclinic space group C2/c with a = 13.409(2) Å, b = 21.670(3) Å, c = 13.726(2) Å, # = 94.865(2)°, V = 3973.9(8) ų, and Z = 4. A minor product, [Rh2(O2CCH3)2(pynp)2(CH3CN)2][BF4][PF6]·2CH3CN (4), was isolated from the mother liquor after crystals of 3 had been harvested; this compound crystallizes in the triclinic space group, P&onemacr; with a = 12.535(3) Å, b = 13.116(3) Å, c = 13.785(3) Å, ! = 82.52(3)°, # = 77.70(3)°, % = 85.76(3)°, V = 2193.0(8) ų, and Z = 2. Compounds 1m3 constitute a convenient series for probing the influence of the electronic configuration on the extent of mixing of the MmM orbitals with the ? system of the pynp ligand. Single point energy calculations performed on 1m3 at the B3LYP level of theory lend insight into the bonding in these compounds and allow for correlations to be made with electronic spectral data. Although purely qualitative in nature, the values for normalized change in orbital energies (NCOE) of the frontier orbitals before and after reduction are in agreement with the observed differences in reduction potentials as determined by cyclic voltammetry.

Discusses the synthesis, crystal structure and physical characterization of coordination compounds of bimetallic cyanide-bridged complexes based on the photochromic nitroprusside anion and paramagnetic metal complexes. Synthesis and structural characterization; Mossbauer spectroscopy; Magnetic properties; Differential scanning calorimetry.

• Cobalt polyoxometalates (POMs) are competitive water oxidation electrocatalysts in acidic media. • Performance is closely related to nuclearity, geometry and total charge. • Stability in acidic media depends on the nature of the heteroatom. • POMs outperform IrO 2 in strong acidic electrolytes when stabilized by hydrophobic binders. A series of Cobalt-polyoxometalates (Co-POM) have been incorporated into carbon paste electrodes as insoluble salts of Cs+ or Ba2+. Specifically, we included the lacunary Keggin-type derivatives [Co(H 2 O)(PW 11 O 39)]5– (CoPW 11), [Co(H 2 O)(SiW 11 O 39)]6– (CoSiW 11), [Co(H 2 O)(CoW 11 O 39)]7– (CoCoW 11), [Co 4 (H 2 O) 2 (PW 9 O 34) 2 ]10– (Co 4 P 2 W 18), [Co 4 (H 2 O) 2 (SiW 9 O 34) 2 ]12– (Co 4 Si 2 W 18), and [Co 9 (H 2 O) 6 (OH) 3 (HPO 4) 2 (PW 9 O 34) 3 ]16– (Co 9); and the lacunary Dawson-Wells derivative [Co 4 (H 2 O) 2 (P 2 W 15 O 56) 2 ]16– (Co 4 P 4 W 30). The activity and stability of these composite electrodes towards water oxidation in acidic media (pH < 1) was examined by electrochemical methods and post-catalytic characterization. Our results indicate the stability of these catalysts in these conditions depends on composition, since only those species containing PV as heteroatom appeared to be stable. All SiIV and CoIII derivates showed rapid decomposition, regardless their nuclearity or molecular structure. All stable derivatives exhibited consistent activity, favored by high nuclearity and overall total charge, with Keggin derivatives being intrinsically more active than the corresponding Dawson-Wells analogues. [ABSTRACT FROM AUTHOR]