A tetra Co(II/III) complex with an open cubane CoO core and square-pyramidal Co(II) and octahedral Co(III) centres: bifunctional electrocatalytic activity towards water splitting at neutral pH.

The reaction of 2,6-diformyl-4-methylphenol, 4-methoxybenzoylhydrazine and Co(OAc)·4HO in 1 : 2 : 2 mole ratio in methanol under aerobic conditions produced in 61% yield a tetranuclear complex having the molecular formula [CoCo(μ-OAc)(μ-OH)(μ-L)] where OAc and L represent acetate and ',''-(5-methyl-2-oxido-1,3-phenylene)bis(methan-1-yl-1-ylidene)bis(4-methoxybenzoylhydrazonate), respectively. The elemental analysis and the mass spectrometric data confirmed the molecular formula of the complex. It is electrically non-conducting and paramagnetic.

A Diuranyl(VI) Complex and Its Application in Electrocatalytic and Photocatalytic Hydrogen Evolution from Neutral Aqueous Medium.

The reaction of equimolar amounts of UO(OAc)·2HO, 2,6-diformyl-4-methylphenol, and -(hydroxyethyl)ethylenediamine in methanol affords a dinuclear -uranyl(VI) complex of the molecular formula [(UO)(μ-L)] (L = 2-formyl-4-methyl-6-((2-(2-oxidoethylamino)ethylimino)methyl)phenolate) in 65% yield. Detailed structural elucidation of the complex was performed by using single-crystal X-ray crystallographic and spectroscopic studies. In [(UO)(μ-L)], the metal centers are in edge-shared pentagonal-bipyramidal NO coordination spheres assembled by the two meridional ONNO-donor bridging L and two pairs of mutually trans oriented oxo groups.

cis-{MoO2}(2+) assisted Mannich-type addition of acetylacetonate methine to the azomethine of tridentate Schiff bases: racemic complexes with chiral transformed ligands.

Reactions of [MoO2(acac)2] (acac(-) = acetylacetonate) with the potential N2O-donor 5,5-membered fused chelate rings forming Schiff bases 2-(2-pyridylaldimine)ethanol (HL(1)) and 4/5-R-2-(2-pyridylaldimine)phenols (HL(n); n = 2-5 for R = H, 4-Cl, 4-Me and 5-Me, respectively) lead to the facile formation of racemic complexes of the general formula cis-[MoO2(acacL(1-5))] () in 80-85% yield. Here, (acacL(n))(2-) represents a chiral N2O2-donor ligand system formed by a novel Mannich-type reaction that involves acetylacetonate and the azomethine fragment of HL(n) both coordinated to the cis-{MoO2}(2+) unit. The characterization of has been performed with the help of microanalytical (CHN), spectroscopic (ESI-MS, IR, UV-Vis and (1)H- and (13)C-NMR) and electrochemical measurements.

Dinuclear triple helicates with diazine ligands: X-ray structural, electrochemical, and magnetic studies.

A series of dinuclear complexes of Mn(III), Fe(III), and Co(III) with two diazine Schiff bases, H2salhn and H2mesalhn, is reported. The Schiff bases are prepared by condensation reactions of hydrazine with salicylaldehyde (H2salhn) and with 2-hydroxyacetophenone (H2mesalhn) in 1:2 mol ratio. X-ray crystallographic characterization reveals triple helical structures of [Co2(salhn)3], [Co2(mesalhn)3], and [Fe2(mesalhn)3].

Enantiospecific inclusion of chiral 1,2-dichloroethane rotamers in the crystal lattice of chiral square-pyramidal Cu(II) complexes with perfectly polar alignment of guest and host molecules.

The inclusion compounds, [CuL(1)2(H2O)].(P)-C2H4Cl2 and [CuL(2)2(H2O)].(M)-C2H4Cl2(HL1 = N-(2-hydroxy-5-nitrobenzyl)-(R)-alpha-methylbenzylamine and HL2 = N-(2-hydroxy-5-nitrobenzyl)-(S)-alpha-methylbenzylamine), crystallise in the non-centrosymmetric space group C2; intermolecular hydrogen bonding leads to a perfectly polar alignment of both host and guest molecules with enantioselectivity.

Chloride ligation in inorganic manganese model compounds relevant to photosystem II studied using X-ray absorption spectroscopy.

Chloride ions are essential for proper function of the photosynthetic oxygen-evolving complex (OEC) of Photosystem II (PS II). Although proposed to be directly ligated to the Mn cluster of the OEC, the specific structural and mechanistic roles of chloride remain unresolved. This study utilizes X-ray absorption spectroscopy (XAS) to characterize the Mn-Cl interaction in inorganic compounds that contain structural motifs similar to those proposed for the OEC.

A novel carboxylate-free ferromagnetic trinuclear mu(3)-oxo-manganese(III) complex with distorted pentagonal-bipyramidal metal centers.

In methanol, the reaction of Mn(ClO(4))(2).6H(2)O and 1,2-bis(biacetylmonoximeimino)ethane (H(2)bamen) in the presence of triethylamine affords a trinuclear complex having the formula [Mn(3)(mu(3)-O)(mu(3)-bamen)(3)]ClO(4).2H(2)O.

trans-(2-Acetylpyridine-kappa2N,O)dichlorobis(dimethyl sulfoxide-kappaS)ruthenium(II).

In the title complex, [RuCl(2)(C(7)H(7)NO)(C(2)H(6)OS)(2)], the metal ion is at the centre of a distorted octahedral NOCl(2)S(2) coordination sphere. The neutral 2-acetylpyridine ligand binds to the metal ion through the pyridine N and carbonyl O atoms, forming a five-membered chelate ring. The monodentate S-coordinating dimethyl sulfoxide molecules are mutually cis, and the two remaining positions in the coordination sphere are occupied by two mutually trans Cl(-) ions.