121619-92-9Relevant articles and documents
The hurtley reaction. 2. Novel complexes of disubstituted acetylenes with copper(I) benzoates having a reactive ortho C-Cl or C-Br bond. X-ray structural characterization of tetrakis(2-chlorobenzoato)bis(diethyl acetylenedicarboxylate)tetracopper(I)
Aalten, Henk L.,Van Koten, Gerard,Riethorst, Ed,Stam, Casper H.
, p. 4140 - 4146 (2008/10/08)
Tetrameric copper(I) benzoate, [Cu(μ-O2CC6H5)]4 (1a), and the o-halogen-substituted copper(I) benzoates [Cu(μ-O2CC6H4-2-Cl)]4 (1b) and [Cu(μ-O2CC6H4-2-Br)]4 (1c), the postulated intermediates in the Hurtley reaction, react with the activated disubstituted acetylenes dimethyl acetylenedicarboxylate (DMAD) and diethyl acetylenedicarboxylate (DEAD) in diethyl ether to yield the stable, soluble, tetranuclear complexes [Cu4(μ-O2CC6H4-2-X) 4(μ-DMAD)2] (X = H (2a), Cl (2b), Br (2c)) and [Cu4(μ-O2CC6H4-2-X) 4(μ-DEAD)2] (X = H (3a), Cl (3b), Br (3c)). The reaction of 1b and 1c with diphenylacetylene in diethyl ether yields the dinuclear complexes [Cu(μ-O2CC6H4-2-X)(PhC≡CPh)] 2 (X = Cl (4b), Br (4c)). In methanol the reaction of [Cu(μ-O2CC6H5)]4 (1a) with DMAD shows a different reactivity pattern, leading to the trimerization of the alkyne. An X-ray structure determination of 3b (C44H36Cl4Cu4O16, triclinic, space group P1, a = 10.973 (3) A?, b = 20.926 (4) A?, c = 10.949 (4) A?, α = 96.76 (2)°, β = 90.96 (3)°, γ = 104.55 (3)°, and Z = 2) has been carried out. The structure, refined to a final R factor of 0.053 with use of 7016 reflections, shows it to be the first copper(I) benzoate compound wherein four copper(I) atoms form a distorted-tetrahedral core. Each of the four benzoate units, acting as a four-electron donor, bridges two adjacent copper atoms (Cu?Cu = 3.027 A? (av)). The two remaining edges of the tetrahedral copper(I) core (Cu?Cu = 2.950 A? (av)) are each perpendicularly bridged by an acetylene unit acting as a four-electron donor; this is the first example of this bonding mode of unsaturated organic compounds in Cu(I) benzoates. All copper atoms have an almost trigonal surrounding consisting of two oxygen atoms (of different benzoates) and the midpoint of the acetylene triple bond. Our attempts to elucidate the structure of the analogous bromo compound 2c were only partially successful due to strong pseudosymmetry in the crystals. The overall structure of 2c appeared to be similar to that of 2b: complex 2c, C40H28Br4Cu4O16, space group Pa, P2/a, or P21/a (monoclinic) with a = 24.658 (4) A?, b = 16.838 (3) A?, c = 12.353 (3) A?, β = 90.08 (3)°, and Z = 4. Variable-temperature 1H NMR spectroscopy and molecular weight determinations of complexes 2 indicate partial dissociation of the coordinated acetylene ligands in solution.
