Structural Diversity of Pentafluorophenylcopper Complexes. First Evidence of π-Coordination of Unsupported Arenes to Organocopper Aggregates

Abstract

The binding behavior of arenes toward pentafluorophenylcopper was investigated. Crystallization of pentafluorophenylcopper from a mixture of 1,2-dichloroethane and cyclohexane affords the homoleptic tetrameric complex [Cu(C6F5)]4, whereas a π-complex, [Cu(C6F5)]4(η2-toluene)2, is obtained from toluene solution. The unique coordination of two toluene molecules in [Cu(C6F5)]4(η2-toluene)2 leads to major structural changes as the regular square planar tetramer is distorted toward a butterfly structure with one short and one long diagonal Cu···Cu distance of 2.5935(3) and 3.955(1) Å, respectively. The toluene molecules are bound in an unsymmetrical η2-coordination mode with the shortest contacts observed between copper and the meta carbon atoms (d(Cu−C) = 2.271(2), 2.298(2) Å) and slightly longer distances to the para positions (d(Cu−C) = 2.339(2), 2.455(4) Å). Multinuclear NMR studies show that complexation to the intact tetrameric cluster species also occurs in neat solution of the aromatic species. Strongly coordinating solvents such as acetonitrile or DMSO, however, lead to aggregate breakdown.

Tris(perfluorotolyl)borane—A Boron Lewis Superacid

“…Thetetrameric aggregation with ab utterfly-like structure is similar to that found for [Cu(C 6 F 5 )] 4 (h 2 -toluene) 2 . [20] Thed ihedral angle between the two Cu 3 triangles [Cu(1)Cu(2)Cu(3) and Cu-(1)Cu(3)Cu (4)] is 36.0(1)8 8.C opper atoms Cu(2) and Cu(4) are h 2 -coordinated by toluene with short contacts to the paracarbon atom (Cu(2)-C(29) 2.302(2) )a nd slightly longer contacts to the meta-carbon atom (Cu(2)-C(30) 2.354(2) ). Thec opper atoms are bridged by perfluoroaryl groups with ac opper contact of 2.601(1) between the non-toluenecoordinated atoms Cu(1) and Cu(3).…”

Copper(I) Alkynyl Clusters, [Cux+y(hfac)x(CCR)y], with Cu10–Cu12 Cores

“…In some cases [14,15,17] the C ipso atoms lie in the same plane as the Cu 4 core, but in the other examples [13,16,18] they are located alternately above and below the Cu 4 plane forming a puckered ring as in Figure 2 (top). The pinching in of the Cu atoms shown in Figure 1 varies considerably with some C-Cu-C units [13,16] being linear within experimental error. A rhombus-shaped Cu 4 core is observed in the dimethylsulfide and thiophene [19][20][21] (Figure 2 bottom).…”

“…In the longer term it was intended to establish whether the larger clusters (Cu [16][17][18][19][20][21][22][23][24][25][26] ) are formed by assembly of these motifs.…”

“…Subsequently [Cu 4 A C H T U N G T R E N N U N G (aryl) 4 ] analogues have been characterized [aryl = 2,4,6-triisopropylphenyl (2,4,6-iPr 3 C 6 H 2 À ), [13] pentamethylphenyl (C 6 Me 5 À ), [14] thienyl (C 4 H 3 S À ), [15] pentafluorophenyl (C 6 F 5 À ), [16] mesityl (2,4,6-Me 3 C 6 H 2 À ) [17] and o-…”

Mono‐ and Dimetalated Ferrocenylcopper Complexes by Tin–Copper Exchange

“…A solution of [FcSnMe 3 ] (1) in hexanes was treated with half an equivalent of [C 6 F 5 Cu] 4 [16,17] in toluene at ambient temperature (Scheme 1). [18] The color of the mixture gradually changed from yellow to orange.…”