Nitrogen reduction by the Fe sites of synthetic [MoSFe] cubes.

Nitrogen (N) fixation by nature, which is a crucial process for the supply of bio-available forms of nitrogen, is performed by nitrogenase. This enzyme uses a unique transition-metal-sulfur-carbon cluster as its active-site co-factor ([(R-homocitrate)MoFeSC], FeMoco), and the sulfur-surrounded iron (Fe) atoms have been postulated to capture and reduce N (refs. ).

Synthesis, structures, redox properties, and theoretical calculations of thiohalide capped octahedral hexanuclear technetium(iii) clusters.

The first thiohalide μ-capped octahedral hexanuclear technetium clusters with 24 valence electrons, [Tc(μ-S)(μ-Br)Br] [n = 1 ([Tc-SBr]) and n = 2 ([Tc-SBr])] and [Tc(μ-S)(μ-Cl)Cl] ([Tc-SCl]), were synthesized and characterized. The structures of [Tc-SBr], [Tc-SBr], and [Tc-SCl] were determined by single-crystal X-ray analysis. The Tc-Tc bond distances in [Tc-SBr], [Tc-SBr], and [Tc-SCl] are 2.

Synthesis of [MoS] Clusters from Half-Sandwich Molybdenum(V) Chlorides and Their Application as Platforms for [MoSFe] Cubes.

Triangular [MoS] clusters are known to serve as platforms to accommodate a metal atom M, furnishing cubic [MoSM] clusters. In this study, three [MoS] clusters supported by η-cyclopentadienyl (Cp) ligands, [CpMoS] (Cp = CMeSiMe, CMeSiEt, and CMeH), were synthesized via half-sandwich molybdenum chlorides CpMoCl. In the cyclic voltammogram of the [MoS] cluster having CMeH ligands, a weak feature appeared in addition to the [CpMoS] redox process, indicating the interaction between [CpMoS] and the [NBu] cation of the electrolyte, while such a feature was less significant for the CMeSiR variants.

A luminescent dicyanidonitridotechnetium(v) core with tridentate ligand coordination sites.

A novel, luminescent technetium complex, [TcN(CN)2bpa] (bpa = bis-(2-pyridylmethyl)amine), with tridentate ligand coordination sites was synthesized and characterized. Photoemission with a maximum wavelength at 666 nm was observed in the solid-state at 296 K.

Synthesis, structure and valence-trapping vs. detrapping for new trinuclear iron pentafluoro benzoate complexes: possible recognition of organic molecules by ⁵⁷Fe Mössbauer spectroscopy.

New mixed-valence trinuclear iron pentafluorobenzoate complexes were synthesized. Their valence-detrapping and/or valence-trapping phenomena were studied by (57)Fe Mössbauer spectroscopy and X-ray crystallography. For [Fe3O(C6F5CO2)6(py)3]·CH2Cl2 (1), a valence-trapped state was observed at low temperatures, while the valence-detrapped state was observed at room temperature.

Excited-state characteristics of tetracyanidonitridorhenium(V) and -technetium(V) complexes with N-heteroaromatic ligands.

Six-coordinate tetracyanidonitridorhenium(V) and -technetium(V) with axial N-heteroaromatic ligands, (PPh4)2[MN(CN)4L] [M = Re, L = 4-(dimethylamino)pyridine (dmap), 3,5-lutidine (lut), 4-picoline (pic), 4-phenylpyridine (ppy), pyridine (py), 3-benzoylpyridine (3bzpy), 4,4'-bipyridine (bpy), pyrazine (pz), 4-cyanopyridine (cpy), or 4-benzoylpyridine (4bzpy); M = Tc, L = dmap, lut, pic, py, pz, or cpy] were synthesized and characterized. The crystal structures of 11 complexes were determined by single-crystal X-ray analysis. All of the complexes showed photoluminescence in the crystalline phase at room temperature.

Photoluminescence switching with changes in the coordination number and coordinating volatile organic compounds in tetracyanidonitridorhenium(V) and -technetium(V) complexes.

Six-coordinate distorted octahedral tetracyanidonitridorhenium(V) and -technetium(V) complexes with a volatile organic compound (VOC) coordinating at the trans position of a nitrido ligand, (PPh4)2[MN(CN)4L] (M = Re, L = MeOH, EtOH, acetone, or MeCN; M = Tc, L = MeOH), and five-coordinate square-pyramidal tetracyanidonitrido complexes without an axial ligand, (PPh4)2[MN(CN)4] (M = Re or Tc), were synthesized and characterized. Single-crystal X-ray structural analysis was carried out for (PPh4)2[MN(CN)4L] (M = Re, L = MeOH, EtOH, or acetone; M = Tc, L = MeOH) and (PPh4)2[ReN(CN)4]. All complexes studied showed photoluminescence in the solid state at room temperature.

Synthesis, spectroscopic and electrochemical properties, and electronic structures of octahedral hexatechnetium(III) clusters [Tc6Q8(CN)6]4- (Q = S, Se).

Chalcogenide-capped molecular octahedral hexatechnetium(III) clusters [Tc(6)Q(8)(CN)(6)](4-) {Q = S ([1](4-)), Se ([2](4-))} were prepared by the substitution of axial ligands with cyanide. The structures of the new complexes were determined by single-crystal X-ray analysis. The IR spectra of [1](4-) and [2](4-) showed a C[triple bond]N stretching band at 2114 and 2105 cm(-1), respectively.