Reaction of trans-Ru(DMSO)4Cl2 with DMAP (DMAP = 4-dimethylaminopyridine) yields the yellow [Ru(DMAP)6](2+) cation in good yield. The crystal and molecular structure of [Ru(DMAP)6]Cl2.6CH3CH2OH was determined by X-ray diffraction methods. The complex crystallizes in the trigonal R3 space group with a = b = 16.373(1), c = 20.311(1) A, gamma = 120 degrees , and Z = 3 molecules per unit cell. The reaction of [Ru(DMAP)6](2+) in aerobic water gives the red [Ru(III)(DMAP)5(OH)](2+) cation. This complex shows a chemical behavior similar to [Ru(III)(NH3)5Cl](2+) and allows the preparation of a family of [Ru(DMAP)5L](n+) complexes. Their electronic properties indicate that the {Ru(II)(DMAP)5} fragment is a weaker pi-donor than {Ru(II)(NH 3)5}. Our density functional theory (DFT) calculations show that in {Ru(II)(DMAP)5} the DMAP ligands can compete for the pi electron density of the ruthenium making the fragment a weaker pi-donor.

The NIR donor-acceptor charge transfer (DACT) bands of the series of trinuclear complexes trans-[(NC)5Fe(II/III)(mu-CN)RuIIL4(mu-NC)FeIII(CN)5](5/4-) (L= pyridine, 4-tert-butylpyridine, and 4-methoxypyridine) are analyzed in terms of a simplified molecular orbital picture that reflects the interaction between the donor and acceptor fragments. The degree of electronic coupling between the fragments is estimated by a full fit of the DACT band profiles according to a three-state model inspired in the Mulliken-Hush formalism. The information is complemented with determinations performed on the asymmetric heterotrinuclear species trans-[(NC)5CoIII(mu-CN)RuII(py)4(mu-NC)FeIII(CN)5]4-, whose preparation is reported here for the first time. The analysis of the NIR spectra of the symmetric trans-[(NC)5FeIII(mu-CN)RuIIL4(mu-NC)FeIII(CN)5]4- species reveals a low degree of mixing between the terminal acceptor fragments and the bridging moiety containing RuII, with H12 values between 1.0 x 10(3) and 1.5 x 10(3) cm-1. The reorganization energy contributions seem to be the same for the three species, even when the spectra were recorded in different media. This observation also applies for the CoIII-substituted compound. The computed potential energy surfaces (PES) of the ground state for these complexes show only one stationary point, suggesting that the FeII-RuIII-FeIII (or FeII-RuIII-CoIII) electronic isomers are not thermally accessible. One-electron reduction leads to asymmetric trans-[(NC)5FeII(mu-CN)RuIIL4(mu-NC)FeIII(CN)5]5- compounds with potentially two DACT bands involving the RuII and the FeII donor fragments. These species reveal a similar degree of electronic mixing but the PES shows three minima. We explore the role of the bridging fragment in the long-range thermally induced electron transfer between the distant iron centers. The results suggest that superexchange and hopping might become competitive paths, depending on the substituents in the bridging fragment.

We report the properties of a trinuclear cyanido-bridged complex, trans- [(dmap) 4 Ru II {(µ-NC)Os III (CN) 5 } 2 ] 4-[1 4-; dmap = 4-(dimethylamino)pyridine], whose structure and elecOver the last 40 years, considerable attention has been given to mixed-valence complexes, systems where an element presents more than one oxidation state, with transition metal compounds of group 8 as the more outstanding examples.[1] One of the areas of interest in this field is to identify systems in the frontier between the so-called localized systems or Class II, [2] according to the classification proposed by Robin and Day, [3] and the delocalized systems or Class III. To identify systems as Class III or Class II/ III (localized, but solvent-averaged) [4] several experimental criteria have been proposed [4,5] including (1) the shape, intensity and solvent dependence of the intervalence transition, (2) direct evidence of localization from crystal structure, spectroscopic markers, the appearance of symmetrical bridging-ligand vibrations and the appearance of nonaveraged spectator vibrations. Due to all the effort devoted to this area, several examples of Class III mixed-valence complexes have been identified, [6] and a few of them show identical coordination spheres for both centers in their crystal structures.[7] Non-symmetrical mixed-valence complexes have also been explored. The absence of symmetry could be due to the presence of a different ligand set for each metal atom, the presence of a non-symmetrical bridge or different elements with different redox states. In this case, a delocalized Class III system would not be symmetrical, and some of the previous experimental criteria can not be applied as they rely on the symmetry of the delocalized system. Cyanido-bridged dinuclear dimers are one of the most intensively studied families of mixed-valence complexes. [8] The exploration of the properties of these dimers, which are non-symmetrical due to the intrinsic asymmetric nature of the bridge, points to a strong coupling, measured through [a]

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The aim of this paper was to carry out a comprehensive study of wheat flour breads fortified with different sources of calcium, which includes: technological, nutritional and sensorial characteristics. Calcium salts (lactate: LA, carbonate: CA, and citrate: CI) at two fortification levels (20% and 50%) were analysed. Only the LA fortified breads were harder with lower specific volume and the LA 50% showed the higher chewiness value. The crust colour of the CI 50% breads presented the lower browning index. In vitro nutritional studies showed that calcium content on digest and dialysate was significantly higher in all fortified breads. The CI 20% and all the 50% fortifications showed a better contribution of bioaccessible calcium. Sensorial general quality was not significantly different between fortified and Control breads.

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