Influence of nitro substituents on the redox, electronic, and proton reduction catalytic behavior of phenolate-based [NO]-type cobalt(iii) complexes.

We report on the synthesis, redox, electronic, and catalytic behavior of two new cobalt(iii) complexes, namely [CoIII(L1)MeOH] (1) and [CoIII(L2)MeOH] (2). These species contain nitro-rich, phenolate-based pentadentate ligands and present dramatically distinct properties associated with the position in which the -NO2 substituents are installed. Species 1 displays nitro-substituted phenolates, and exhibits irreversible redox response and negligible catalytic activity, whereas 2 has fuctionalized phenylene moieties, shows much improved redox reversibility and catalytic proton reduction activity at low overpotentials.

A pentadentate nitrogen-rich copper electrocatalyst for water reduction with pH-dependent molecular mechanisms.

The new pentadentate 3d complex [Cu(L)](PF) (1) based on a nitrogen-rich framework acts as an electrocatalyst toward dihydrogen production from water. This species is active at pHs 7 and 2.5 yielding respective TON values of 1670 and 3900.

Bimetallic Cooperativity in Proton Reduction with an Amido-Bridged Cobalt Catalyst.

The bimetallic catalyst [Co (L )(bpy) ]ClO (1), in which L is an [NN' O ] fused ligand, efficiently reduced H to H in CH CN in the presence of 100 equiv of HOAc with a turnover number of 18 and a Faradaic efficiency of 94 % after 3 h of bulk electrolysis at -1.6 V (vs. Ag/AgCl).

Efficient electro/photocatalytic water reduction using a [Ni(NPy)] complex.

The pyridine-rich complex [Ni(L)(MeCN)](ClO) (1) acts as an efficient electro- and photocatalyst in the generation of H from water. Observed TONs reach 1050 for electrocatalysis and a remarkable 3500 for photocatalysis. Experimental and DFT data support the ligand-reduced [NiL˙] as the catalytically active species, contrasting with the [CoL] observed for cobalt catalysts.

Langmuir-Blodgett films of salophen-based metallosurfactants as surface pretreatment coatings for corrosion mitigation.

Salophen-based metallosurfactants are successfully used as pretreatment LB films for corrosion mitigation in acidic and saline media. Passivation of electron transfer is clearly demonstrated in gold electrodes, while 99.5% iron substrates treated with such films show up to an impressive 30% corrosion mitigation.

Electronic Modulation of the SOMO-HOMO Energy Gap in Iron(III) Complexes towards Unimolecular Current Rectification.

Amphiphilic five-coordinate iron(III) complexes with {N2 O2 Cl} and {N2 O3 } coordination spheres are studied to elucidate the roles of electronic structure on the mechanisms for current rectification. The presence of an apical chlorido or phenolato ligand plays a crucial role, and the [Fe(III) {N2 O2 Cl}] species supports an asymmetric mechanism while its [Fe(III) {N2 O3 }] counterpart seems to allow for unimolecular mechanism. The effects of electron-donating and electron-withdrawing substituents in the ligand frameworks are also considered.

Crystal structure of tetra-kis-(μ-N-phenyl-acetamidato)-κ(4) N:O;κ(4) O:N-bis-[(2-methyl-benzo-nitrile-κN)rhodium(II)](Rh-Rh).

The complex molecule of the title compound, [Rh2{N(C6H5)COCH3}4(C8H7N)2], exhibits inversion symmetry. The four acetamidate ligands bridging the dirhodium core are arranged in a 2,2-trans manner with two N atoms and two O atoms coordinating to each Rh(II) atom trans to one another. The Neq-Rh-Rh-Oeq torsion angles on the acetamidate bridge vary between -4.

(3-Methyl-benzo-nitrile-κN)tetra-kis(μ-N-phenyl-acetamidato)-κ(4) N:O;κ(4) O:N-di-rhodium(II)(Rh-Rh).

In the title compound, [Rh2(C8H8NO)4(C8H7N)], the four acetamidate ligands bridging the dirhodium core are arranged in a 2,2-trans manner. One Rh(II) atom is five-coordinate, in a distorted pyramidal geometry, while the other is six-coord-in-ate, with a disorted octa-hedral geometry. For the six-coord-inate Rh(II) atom, the axial nitrile ligand shows a non-linear Rh-nitrile coordination with an Rh-N-C bond angle of 166.

Electronic and interfacial behavior of gemini metallosurfactants with copper(II)/pseudohalide cascade cores.

In this paper we discuss the newly synthesized binuclear species [Cu2(L(PY18))2(μ1,1-N3)2(N3)2] (1) and [Cu2(L(PY18))2(μ1,3-SCN)2(NCS)2] (2), as obtained from the monometallic precursor [Cu(L(PY18))Br2]. These gemini metallosurfactants incorporate metal/anion cascade cores and are investigated by experimental and theoretical methods. Diagnostic IR stretches support the presence of μ1,1-bridged (end-on, 2075 cm(-1)) azide groups in 1 and μ1,3-bridged (end-to-end, 2117 cm(-1)) thiocyanate groups in 2.

Tetra-kis[μ-N-(2,4,6-trimethyl-phen-yl)acetamidato]-κ⁴N:O;κ⁴O:N-bis-[(benzo-nitrile-κN)rhodium(II)](Rh-Rh).

The title structure, [Rh₂(C₁₁H₁₄NO)₄(C₇H₅N)₂], contains a dinuclear Rh complex of point symmetry -4 with an Rh-Rh unit and two benzonitrile ligands located in special positions along the twofold axis passing through -4. Four symmetry-equivalent mesitylacetamidate ligands bridge the Rh-Rh unit. Thus, each Rh(II) atom has an approximately octa-hedral coordination by one Rh [Rh-Rh = 2.