3 research outputs found

    Rhenium Selenide Clusters Containing Alkynyl Ligands: Unexpected Reactivity of σ‑Bound Phenylacetylide

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    Three organometallic rhenium-based clusters containing phenylacetylide ligands, [Re6Se8(PEt3)5(CC–Ph)](SbF6) (1) and cis- and trans-[Re6Se8(PEt3)4(CC–Ph)2] (2 and 3), were synthesized and fully characterized including single-crystal X-ray diffraction analyses. Reactivity studies of 1 show that reaction with electrophilic reagents does not result in the formation of the vinylidene species as predicted; instead, elimination of the acetylide moiety is observed. Products isolated from these reactions, including the methyl sulfate complex, [Re6Se8(PEt3)5(OSO3Me)](SbF6) (4), have been characterized along with those obtained from the [2 + 2] cycloadditions of 1 with tetracyanoethylene and 7,7,8,8-tetracyanoquinodimethane. The relative reactivities of the electrophilic agents utilized are compared. Preliminary computational studies reveal useful information about the nature of the [Re6Se8]2+–acetylide bond and aid in our understanding of the reactivity associated with this cluster complex

    Preparation of a Family of Hexanuclear Rhenium Cluster Complexes Containing 5-(Phenyl)tetrazol-2-yl Ligands and Alkylation of 5-Substituted Tetrazolate Ligands

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    The preparation of two new families of hexanuclear rhenium cluster complexes containing benzonitrile and phenyl-substituted tetrazolate ligands is described. Specifically, we report the preparation of a series of cluster complexes with the formula [Re<sub>6</sub>Se<sub>8</sub>(PEt<sub>3</sub>)<sub>5</sub>L]<sup>2+</sup> where L = benzonitrile, <i>p</i>-aminobenzonitrile, <i>p</i>-methoxybenzonitrile, <i>p</i>-acetylbenzonitrile, or <i>p</i>-nitrobenzonitrile. All of these complexes undergo a [2 + 3] cycloaddition with N<sub>3</sub><sup>–</sup> to generate the corresponding [Re<sub>6</sub>Se<sub>8</sub>(PEt<sub>3</sub>)<sub>5</sub>(5-(<i>p-</i>X-phenyl)­tetrazol-2-yl)]<sup>+</sup> (or [Re<sub>6</sub>Se<sub>8</sub>(PEt<sub>3</sub>)<sub>5</sub>(2,5-<i>p-</i>X-phenyltetrazolate)]<sup>+</sup>) cluster complexes, where X = NH<sub>2</sub>, OMe, H, COCH<sub>3</sub>, or NO<sub>2</sub>. Crystal structure data are reported for three compounds: [Re<sub>6</sub>Se<sub>8</sub>(PEt<sub>3</sub>)<sub>5</sub>(<i>p</i>-acetylbenzonitrile)]­(BF<sub>4</sub>)<sub>2</sub>•MeCN, [Re<sub>6</sub>Se<sub>8</sub>(PEt<sub>3</sub>)<sub>5</sub>(2,5<i>-</i>phenyltetrazolate)]­(BF<sub>4</sub>)•CH<sub>2</sub>Cl<sub>2</sub>, and [Re<sub>6</sub>Se<sub>8</sub>(PEt<sub>3</sub>)<sub>5</sub>(2,5<i>-p-</i>aminophenyltetrazolate)]­(BF<sub>4</sub>). Treatment of [Re<sub>6</sub>Se<sub>8</sub>(PEt<sub>3</sub>)<sub>5</sub>(2,5<i>-</i>phenyltetrazolate)]­(BF<sub>4</sub>) with HBF<sub>4</sub> in CD<sub>3</sub>CN at 100 °C leads to protonation of the tetrazolate ring and formation of [Re<sub>6</sub>Se<sub>8</sub>(PEt<sub>3</sub>)<sub>5</sub>(CD<sub>3</sub>CN)]<sup>2+</sup>. Surprisingly, alkylation of the phenyl and methyl tetrazolate complexes ([Re<sub>6</sub>Se<sub>8</sub>(PEt<sub>3</sub>)<sub>5</sub>(2,5<i>-</i>N<sub>4</sub>CPh)]­(BF<sub>4</sub>) and [Re<sub>6</sub>Se<sub>8</sub>(PEt<sub>3</sub>)<sub>5</sub>(1,5<i>-</i>N<sub>4</sub>CMe)]­(BF<sub>4</sub>)) with methyl iodide and benzyl bromide, leads to the formation of mixtures of 1,5- and 2,5-disubstituted tetrazoles

    Reversible Electrochemical Lithium-Ion Insertion into the Rhenium Cluster Chalcogenide–Halide Re<sub>6</sub>Se<sub>8</sub>Cl<sub>2</sub>

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    The cluster-based material Re<sub>6</sub>Se<sub>8</sub>Cl<sub>2</sub> is a two-dimensional ternary material with cluster–cluster bonding across the <i>a</i> and <i>b</i> axes capable of multiple electron transfer accompanied by ion insertion across the <i>c</i> axis. The Li/Re<sub>6</sub>Se<sub>8</sub>Cl<sub>2</sub> system showed reversible electron transfer from 1 to 3 electron equivalents (ee) at high current densities (88 mA/g). Upon cycling to 4 ee, there was evidence of capacity degradation over 50 cycles associated with the formation of an organic solid–electrolyte interface (between 1.45 and 1 V vs Li/Li<sup>+</sup>). This investigation highlights the ability of cluster-based materials with two-dimensional cluster bonding to be used in applications such as energy storage, showing structural stability and high rate capability
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