Synthesis and Characterization of Heterometallic Clusters (Ir2Rh, Ir2W, Rh3) Containing 1,2-Dicarba-closo-dodecaborane(12)-1,2-dithiolate Chelate Ligands, [(B10H10)C2S2]2−

Hydrosulfide complexes of the transition elements: diverse roles in bioinorganic, cluster, coordination, and organometallic chemistry

Molecules containing transition metal hydrosulfide linkages are diverse, spanning a variety of elements, coordination environments, and redox states, and carrying out multiple roles across several fields of chemistry.

Efficient synthesis of carborane azo derivatives and their reactivity

An iridium(iii)-catalyzed C–N-bond-forming direct synthesis of carborane azo derivatives was developed.

Ir(2-phenylpyridine)2(benzene-1,2-dithiolate) anion as a diastereoselective metalloligand and nucleophile: stereoelectronic effect, spectroscopy, and computational study of the methylated and aurated complexes and their oxygenation products

The anionic complex [Ir(2-phenylpyridine)2(benzene-1,2-dithiolate)](-) ([IrSS](-)) is a nucleophile and metalloligand that reacts with methyl iodide and AuPR3(+) (R = Ph or Et) to form S-methylated complexes (thiother-thiolate and dithiother complexes) and S-aurated complexes, respectively. The reactions are completely diastereselective, producing only the enantiomers ΛS and ΔR or ΛSS and ΔRR. The diastereoselectivity is stereoelectronically controlled by the orientation of the highest occupied molecular orbital (HOMO) of [IrSS](-) arising from filled dπ-pπ antibonding interactions, and the chirality of the iridium ion. Methylation or auration removes the high-energy lone pair of the thiolate S atom, leading to low-lying HOMOs composed mainly of the Ir d-orbital and the 2-phenylpyridine π (ppyπ) orbital. The methylated and aurated complexes can be oxidized by H2O2 or peracid to give sulfinate-thiother, disulfoxide, and sulfinate-sulfoxide complexes, and the oxygenation further stabilizes the HOMO. All the complexes are luminescent, and their electronic spectra are interpreted with the aid of time-dependent density functional theory calculations. The thiother-thiolate complex exhibits ligand(S)-to-ligand(π* of ppy)-charge-transfer/metal-to-ligand-charge-transfer absorption (LLCT/MLCT) and a relatively low-energy (3)LLCT/MLCT emission, while the other complexes display (3)ππ*/MLCT emissions.

Synthesis and reactivity of 4,5-[1,2-dicarba-closo-dodecaborano(12)]-1,3-diselenacyclopentane: opening of the icosahedron to give a zwitterionic intermediate and conversion into 7,8-dicarba-nido-undecaborate(1-)

The reaction of the 1,2-diselenolato-1,2-dicarba-closo-dodecaborane(12) dianion [1,2-(1,2-C(2)B(10)H(10))Se(2)](2-) with dichloromethane (CH(2)Cl(2) or CD(2)Cl(2)) in the presence of donor solvents gave 4,5-[1,2-dicarba-closo-dodecaborano(12)]-1,3-diselenacyclopentane, the title compound, which was characterized by X-ray structural analysis and NMR spectroscopy ((1)H, (11)B, (13)C, and (77)Se). In the presence of pyridine, opening of the icosahedron took place, and a zwitterionic intermediate was isolated and fully characterized in the solid state by X-ray diffraction and in solution by multinuclear magnetic resonance techniques. Although such types of intermediates, prior to deboronation of the ortho-carborane cage, have been proposed several times, this is first example for which the structure has been confirmed unambiguously. This intermediate possesses a nido structure and contains a 7,8-dicarba-nido-undecaborate(1-) anion and a boronium cation, the latter with two pyridine rings linked to the boron atom, which has been extruded from the cage. It was shown that this process is reversible as long as the deboronation is not complete. The formation of the intermediate is accompanied by deboronation, which leads to the 7,8-dicarba-nido-undecaborate(1-) anion. The latter was prepared independently by conventional routes from the title compound, isolated as crystalline material as the tetrabutyl ammonium salt, and characterized by X-ray structural analysis and multinuclear magnetic resonance spectroscopy ((1)H, (11)B, (13)C, and (77)Se).

Controlled assembly of ruthenium complexes through ortho-carborane dithiolate and polysulfide ligands

Treatment of ortho-carborane, n-butyl lithium, sulfur, and [(p-cymene)RuCl(2)](2) in varying ratio led to four new compounds (p-cymene)Ru[S(3)(C(2)B(10)H(10))(2)] (3), [(p-cymene)Ru(2)(μ(2)-S(2)C(2)B(10)H(9))(μ(3)-S(2)C(2)B(10)H(10))](2) (4), [(p-cymene)Ru](2)Ru(μ(2)-η(2):η(2)-S(2)) (μ(2)-η(2):η(1)-S(2)Cl)(μ(2)-S(2)C(2)B(10)H(10))(2) (5), and [(p-cymene)Ru](2)Ru(μ(2)-η(1):η(1)-S(2))(μ(3)-η(2):η(2)-S(4)) (μ(2)-S(2)C(2)B(10)H(10))(2) (6), respectively. In 3, the ruthenium atom is coordinated by three S atoms from a in situ generated tridentate [S(3)(C(2)B(10)H(10))(2)](2-) ligand. 4 consists of two identical dinuclear (p-cymene)Ru(2)(μ(2)-S(2)C(2)B(10)H(9))(μ(3)-S(2)C(2)B(10)H(10)) subunits which connect to each other via the Ru-Ru bond and two bridging o-carborane-1,2-dithiolate ligands. In 4, a Ru-B bond is present. 5 contains a Ru(3)(μ(2)-S)(2)(μ(2)-S(2))(μ(2)-S(2)Cl) core, and the central ruthenium atom is coordinated by seven S atoms in a distorted pentagonal bipyramidal geometry. In 5, a S-Cl bond is generated. 6 has a novel Ru(3)(μ(2)-S)(2)(μ(2)-S(2))(μ(3)-S(4)) core, and the three ruthenium atoms are connected through the two terminal sulfur atoms of the S-S-S-S chain in a μ(3) binding fashion. All the four complexes have been characterized by elemental analysis, mass, NMR, and X-ray crystallography.

Solvent-Dependent Interconversions between RhI, RhII, and RhIII Complexes of an Aryl–Monophosphine Ligand

Reaction of the aryl-monophosphine ligand alpha(2)-(diisopropylphosphino)isodurene (1) with the Rh(I) precursor [Rh(coe)(2)(acetone)(2)]BF(4) (coe=cyclooctene) in different solvents yielded complexes of all three common oxidation states of rhodium, depending on the solvent used. When the reaction was carried out in methanol a cyclometalated, solvent-stabilized Rh(III) alkyl-hydride complex (2) was obtained. However, when the reaction was carried out in acetone or dichloromethane a dinuclear eta(6)-arene Rh(II) complex (5) was obtained in the absence of added redox reagents. Moreover, when acetonitrile was added to a solution of either the Rh(II) or Rh(III) complexes, a new solvent-stabilized, noncyclometalated Rh(I) complex (6) was obtained. In this report we describe the different complexes, which were fully characterized, and probe the processes behind the remarkable solvent effect observed.

Construction of trinuclear iridium clusters through ancillary ortho-carborane-1,2-diselenolato ligands, with simultaneous iridium-induced B–H activation

The reaction of the 16-electron "pseudo-aromatic" complex Cp*Ir[Se2C2(B10H10)] (1, Cp* = eta5-C5Me5) with [Ir(cod)(micro-OC2H5)]2 leads to the trinuclear iridium complexes {(cod)Ir[Se2C2(B10H8)(OC2H5)]}Ir{[Se2C2(B10H10)]IrCp*} (2), {(cod)Ir[Se2C2(B10H8)(OC2H5)]}Ir{[Se2C2(B10H9)]IrCp*} (3), {Cp*Ir[Se2C2(B10H9)]}{IrSe(2)[C2(B10H9)(OC2H5)]}{[Se2C2(B10H10)] IrCp*} (4) and one mononuclear complex Cp*Ir[Se2C2(B10H8)(OC2H5)(2)] (5). The reactivity of 2 was investigated and revealed that transformation from 2 to 3 occurred thermally in solution. The transoid complex 2 (with the carborane diselenolato units in trans position) can be converted in nearly 90% yield to the cisoid complex 3. In complexes 2, 3, two diselenolato carborane ligands bridge the Ir(3) core, which consists of Ir-Ir metal bonds. Compared with transoid 2, the cisoid 3 contains two iridium-boron bonds. Complex 4 consists of three different coordination environment carborane ligands (Ir-B(cluster): {Cp*Ir[Se2C2(B10H9)]}, O-B(cluster): {[Se2C2(B10H9)](OC2H5)}, and intact carborane: {Cp*Ir[Se2C2 (B10H10)]}) without the presence of a metal-metal bond. Analogous reaction of 1 with [Ir(cod)(micro-OCH(3))](2) results in formation of the trinuclear complex {Cp*Ir[Se2C2(B10H9)]}{IrSe(2)[C2(B10H9)(OCH3)]}{[Se2C2(B10H10)]IrCp*} (6) and mononuclear complex Cp*Ir[Se2C2(B10H8)(OCH3)(2)] (7). The structures of 2, 3, 4, 5, 6 and 7 have been determined by crystallographic studies.

Formation of direct metal–metal bonds from 16-electron “pseudo-aromatic” half-sandwich complexes Cp″M[E2C2(B10H10)]

Continuous study on preparation of multimetallic clusters is stimulated by their rich coordination chemistry and promising applications in a variety of interesting fields. Although numerous efforts have been devoted to this field, the rational design of homo- and hetero-multimetallic compounds with direct metal-metal bonding supported by 1,2-dicarba-closo-dodecarborane-1,2-dichalcogenolates will still be an important step forward. This tutorial review focuses on the synthetic approach via redox reactions between the pseudo-aromatic half-sandwich oraganometallic carborane precursors and low-valent transition metal reagents. The tailoring of reaction conditions and the structural information from the resulting products are discussed extensively.

Binuclear half-sandwich cobalt(iii) and rhodium(iii) ortho-carboranedichalocogenolato complexes with ether chain-bridged bis(cyclopentadienyl) ligand

1, 1'-(3-Oxapentamethylene)dicyclopentadiene [O(CH(2)CH(2)C(5)H(5))(2)], containing a flexible chain-bridged group, was synthesized by the reaction of sodium cyclopentadienide with bis(2-chloroethyl) ether through a slightly modified literature procedure. Furthermore, the binuclear cobalt(III) complex O[CH(2)CH(2)(eta(5)-C(5)H(4))Co(CO)I(2)](2) and insoluble polynuclear rhodium(III) complex {O[CH(2)CH(2)(eta(5)-C(5)H(4))RhI(2)](2)}(n) were obtained from reactions of with the corresponding metal fragments and they react easily with PPh(3) to give binuclear metal complexes, O[CH(2)CH(2)(eta(5)-C(5)H(4))Co(PPh(3))I(2)](2) and O[CH(2)CH(2)(eta(5)-C(5)H(4))Rh(PPh(3))I(2)](2), respectively. Complexes react with bidentate dilithium dichalcogenolato ortho-carborane to give eight binuclear half-sandwich ortho-carboranedichalcogenolato cobalt(III) and rhodium(III) complexes O[CH(2)CH(2)(eta(5)-C(5)H(4))Co(PPh(3))(E(2)C(2)B(10)H(10))](2) (E = S and Se), O[CH(2)CH(2)(eta(5)-C(5)H(4))](2)Co(2)(E(2)C(2)B(10)H(10)) (E = S and Se), O[CH(2)CH(2)(eta(5)-C(5)H(4))Co(E(2)C(2)B(10)H(10))](2) (E = S and Se and O[CH(2)CH(2)(eta(5)-C(5)H(4))Rh(PPh(3))(E(2)C(2)B(10)H(10))](2) (E = S and Se). All complexes have been characterized by elemental analyses, NMR spectra ((1)H, (13)C, (31)P and (11)B NMR) and IR spectroscopy. The molecular structures were determined by X-ray diffractometry.

Synthesis and characterization of binuclear half-sandwich metal (Co, Ir and Ru) complexes containing ancillary ortho-carborane-1,2-dithiolato ligands

The assembly of soluble, air-stable, binuclear structures, namely {(p-cymene)Ru[S(2)C(2)(B(10)H(10))]}(2)(micro-pyz), {Cp*Co[S(2)C(2)(B(10)H(10))]}(2)(micro-pyz), {Cp*Co[S(2)C(2)(B(10)H(10))]}(2)(micro-bpy), {Cp*Co[S(2)C(2)(B(10)H(10))]}(2)(micro-bpe) and {Cp*Ir[E(2)C(2)(B(10)H(10))]}(2)(micro-bpo) (E = S (), Se), in which organometallic units are bridged by pyridyl-based organic linkers, are synthesized. The complexes have been fully characterized by IR and NMR spectroscopy, as well as elemental analysis. The molecular structures are established through X-ray crystallography.