Reactivity of the Unsaturated Anion Decacarbonyltetra-μ-hydrido-trirhenate(1-) toward Phenols. Crystal and Molecular Structures of the Tetraethylammonium Salts of the Triangular Cluster Anion - and of the Binuclear Anion -

DOI: 10.1039/DT9850001507

Source and publish data:

Journal of the Chemical Society, Dalton Transactions p. 1507 - 1512 (1985)

Update date:2022-07-30

Topics:

Authors:

Beringhelli, Tiziana

Ciani, Gianfranco

D'Alfonso, Giuseppe

Sironi, Angelo

Freni, Maria

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Article abstract of DOI:10.1039/DT9850001507

The reactions of ^- with phenols have been investigated under different conditions.The acidity of phenols is sufficient to abstract one hydride of the Re(μ-H)2Re system leading to compounds ^- (R = H or F) or, under a CO atmosphere, to neutral .The NEt4⁺ salt of the pentafluorophenoxide derivative has been investigated by X-ray analysis.The crystals are monoclinic, space group P2₁/c, with a=9.304(1), b=19.357(3), c=18.063(3) Angstroem, β=94.72(1) deg, and Z=4.The structure was solved and refined on the basis of 3 897 significant counter data, to a final R 0.028.The anion contains an isosceles triangle of Re atoms, with two longer hydride-bridged edges <3.215(1) and 3.243(1) Angstroem> and one shorter edge <2.975(1) Angstroem> doubly bridged by a hydride and the phenoxide ligand .Reaction of ^- with an excess of phenol at high temperature leads to cluster degradation, with formation of the binuclear anion ^-.The NEt4⁺ salt of the latter has been studied by single-crystal X-ray analysis: orthorhombic, space group Pc2₁n (nonstandard setting of Pna2₁), with a=9.568(1), b=18.865(3), c=18.948(3) Angstroem, and Z=4.The structure solution and refinements were based on 2 168 significant counter data, the final R value being 0.031.The anion contains two Re(CO)3 units, joined through three phenoxide bridges.The mean Re-O bond length is 2.14 Angstroem, and the non-bonding Re...Re contact is 3.154(1) Angstroem.Pyrolysis in n-heptane of ^- gives selectively ^-, in a reaction that is readily reversed under CO at room temperature.