Gregory L. Powell

Isolation and structure of [Re2Cl7(dto)]−. A quadruply bonded intermediate in an intramolecular disproportionation reaction

Abstract The preparation and structural characterization of (n-Bu4N)[Re2Cl7(dto)] (dto = 3,6-dithiaoctane) is described. Crystallographic parameters at 20°C are a = 11.299 (3), b = 11.552 (4), c = 14.645 (4) A, α = 108.19 (2)°, β = 104.07 (2)°, γ = 88.65 (3)°, Z = 2, and space group P−1. This compound is the first example of a quadruply bonded complex of the type [Re2X7(LL)]−. The anion has a slightly staggered structure in which the dto ligand coordinates in an equatorial-axial arrangement on one Re atom. The Re-Re bond distance is 2.248 (1) A. This complex is an air-stable intermediate in the formation of triply bonded Re2Cl5(dto)2 from quadruply bonded (n-Bu4N)2[Re2Cl8].

Preparation and characterization of dirhenium complex anions of the type [Re2Cl7(dithioether)]− with ReRe quadruple bonds

Two dirhenate(III) anions containing dithioether ligands and ReRe quadruple bonds have been synthesized and characterized by X-ray crystallography. Under mild reaction conditions, both 3,6-dithiaoctane (Ch3CH2SCH2CH2SCH2CH3 or dto) and 2,5-dithiahexane (CH3SCH2CH2SCH3 or dth) displace a single chloride ligand from [Re2Cl8]2− to yield [Re2Cl7(dto)]− and [Re2Cl7(dth)]−, respectively. The tetra-n-butylammonium (Bu4N) salts of these complex ions have been isolated and found to react with additional dithioether to produce the unsymmetrical compounds Re2Cl5(dto)2 and Re2Cl5(dth)2 with ReRe triple bonds. The complex (Bu4N[Re2Cl7(dto)] crystallizes in the triclinic space group P1 with a = 11299(3), b = 11.552(4), c = 14.654(4)A, a = 108.19(2), β = 104.07(2), γ = 88.65(3)° and Z = 2, while (Bu4N)[Re2Cl7(dth)] crystalline in the monoclinic space group P21 with a = 10.361(2), b = 15.567(4), c = 11.663(3) A, β = 117.01(2)° and Z = 2. The ReRe bond distances are 2.248(1) and 2.257(1) A for the dto and dth complexes, respectively.

Preparation and characterization of [(LL)Cl2Mo]2(μ-SPr)2 compounds with Prn-propyl and LLPrSCH2CH2SPr and Et2PCH2CH2PEt2. Further examples of CS bond cleavage and oxidative addition across an MoMo quadruple bond

Abstract Two dimolybdenum(III) complexes with edge-sharing bioctahedral geometries have been synthesized and structurally characterized by three-dimensional, single-crystal X-ray diffractometry. Both [(PrSCH 2 CH 2 SPr)Cl 2 Mo] 2 (μ-SPr) 2 ·0.5CH 2 Cl 2 and [(Et 2 PCH 2 CH 2 PEt 2 )Cl 2 Mo] 2 (μ-SPr) 2 where Pr is n-propyl and Et is ethyl (hereafter referred to as 1 and 2 , respectively) crystallize in the monoclinic system with two formula units per cell ( C2 / m and P 2 1 / c , respectively). The MoMo bond distances of 2.682(6) A for 1 and 2.769(1) A for 2 are characteristic of MoMo double bonds. Bond lengths and angles are internally consistent and the van der Waals interactions are normal. Utilizing cone angle calculations, a ‘ligand profile’ describes the steric bulk about the phosphorus atoms in 2 looking down the MoP bonds. The resulting maximum half cone angles, θ/2, are 62±1.0°. Compound 1 was prepared by a reaction involving carbon-sulfur bond cleavage, and separately, by a reaction involving oxidative addition of PrSSPr across the MoMo quadruple bond in Mo 2 Cl 4 (PrSCH 2 CH 2 SPr) 2 Compound 2 was prepared from compound 1 by ligand substitution.

Preparation and crystal structure of the cluster complex Os7H2(CO)21P(OMe)3

Abstract The new osmium cluster complex Os 7 H 2 (CO) 21 P(OMe) 3 , in which P(OMe) 3 is trimethylphosphite, has been synthesized and characterized by X-ray crystallographic analysis. This complex was prepared by the addition of P(OMe) 3 to Os 7 H 2 (CO) 21 . Crystals are monoclinic, space group P 2 1 / c , with a = 14.220(3), b = 12.071(3), c = 24.019(7) A , β = 109.63(2)° and Z = 4. The metal atom arrangement consists of a trigonal bipyramid sharing an equatorial vertex with a triangle. The phosphite ligand is bound to one of the outer vertices of the triangular unit. The physical and chemical behavior of this complex is compared with that of two previously reported clusters alleged to be isomers of Os 7 H 2 (CO) 22 .

Products of the reactions of [Re2X8]2– with 3,6-dithiaoctane (dto). Preparation and crystal structures of Re2Cl5(dto)2, Re2Br5(dto)2, and (n-Bu4N)2Re2(NCS)8·dto

Abstract The reactions of the quadruply bonded complexes (n-Bu4N)2Re2X8 (X=Cl, Br) with excess 3,6-dithiaoctane (CH3CH2SCH2CH2SCH2CH3 or dto) under forcing conditions lead to the compounds Re2Cl5(dto)2 (1) and Re2Br5(dto)2 (2) with Re–Re triple bonds. X-ray crystallographic studies of compounds 1 and 2 reveal a common staggered, unsymmetrical molecular geometry with both dto ligands chelated to the same metal atom. This Re atom is also bonded to a single axial halide ligand, while the other four halides surround the second Re atom. In contrast to the only previous example of this type of dirhenium compound, Re2Cl5(dithiahexane)2, there is no sharing of axial chloride ligands between molecules in the crystal lattices of 1 and 2. The Re–Re bond distances are 2.2772(8) and 2.2826(6) A in 1 and 2, respectively. Magnetic measurements, cyclic voltammetry, and IR, Vis and ESR spectra of 1 and 2 are reported. Addition of dto to a solution of (n-Bu4N)2Re2(NCS)8 leads to the formation of (n-Bu4N)2Re2(NCS)8·dto (3). Crystallographic studies show 3 to consist in the solid state of chains of [Re2(NCS)8]2– units linked together by dto molecules with each dto sulfur atom weakly coordinated to axial sites on Re atoms of different anions. The Re–Re quadruple bond distance in 3 is 2.2854(3) A.

Penta­chloro-1,3,6-tris­(diethyl­phenyl­phosphino)­dirhenium(II,III)

The title complex [systematic name: pentachloro-1kappa(3)Cl,2kappa(2)Cl-tris(diethylphenylphosphino)-1kappaP,2kappa(2)P-dirhenium(II,III)(Re-Re)], 1,3,6-Re(2)Cl(5)(PEt(2)Ph)(3) or [Re(2)Cl(5)(C(10)H(15)P)(3)], consists of dirhenium molecules with eclipsed structures similar to those of previously characterized 1,3,6-Re(2)Cl(5)(PR(3))(3) compounds. The Re-Re bond distance is 2.2262 (3) A and the metal-metal bond order is 3.5.

Reactivity of Dithioethers Toward [Re2X8]2−

The reactivities of 3,6-dithiaoctane (dto) and 2,5-dithiahexane (dth) toward quadruply bonded octahalodirhenate(III) ions have been investigated under a variety of conditions. At or below 50°C, the reaction of [Re2Cl8]2− with dto in ethanol yields a novel quadruply bonded anion, [Re2Cl7(dto)]−. At higher temperatures, this reaction produces the paramagnetic triply bonded compound Re2Cl5(dto)2. Similarly, [Re2Cl7(dth)]− and Re2Cl5(dth)2 have been isolated from reactions between [Re2Cl8]2− and dth in ethanol. The complexes [Re2Cl7(LL)]−, in which LL = dto or dth, have been shown to be intermediates in the synthesis of Re2Cl5(LL)2. No such intermediates have been detected in the reactions of dto and dth with quadruply bonded [Re2Br8]2− to produce Re2Br5(LL)2. No reaction occurs between [Re2X8]2− and dto in dichloromethane, acetone, or acetonitrile. The X-ray crystal structures of (n-Bu4N)[Re2Cl7(dto)]−, (n-Bu4N)[Re2Cl7(dth)]−, Re2Cl5(dto)2, and Re2Br5(dto)2 will be presented.