Synthesis and properties of trimeric ortho-chelated (arenethiolato)copper(I) complexes

Abstract

Neutral (arenethiolato)copper(I) complexes [CuSC6H3(CH(R')NMe2)-2-R"-3]3 (R' = H, R" = H, Cl; R' = Me, R" = H) with an intramolecularly coordinating ligand have been prepared and characterized. Crystals of [CuSC6H4(R-CH(Me)NMe2)-2]3-THF are hexagonal, space group P6}, with a -13.743 (1) A, 6 = 11.248 (1) A, V = 1839.8 (3) A3, Z = 2, and final R = 0.054 for 1448 reflections with I > 2.5<r(/) and 140 variables. The crystals are triboluminescent. The structure contains a Cu3S3 sixmembered ring in a chairlike conformation with alternating copper and sulfur atoms, and on each sulfur atom the C6H3(R-CH-(Me)NMe2)-2 group is bonded equatorially with respect to this ring. Coordination of the nitrogen atoms of the o-CH(Me)NMe2 substituents to the copper atoms (Cu-N = 2.077 (7) A) provides three six-membered CuSCCCN chelate rings. The bridge bonding of the arenethiolate has striking structural features, an acute Cu-S-Cu angle of 79.63 (7)e, Cu-S bond lengths of 2.231 (2) A and 2.186 (2) A, and a short Cu-Cu distance of 2.828 (1) A. These features reflect an electron-deficient two-electron three-center Cu2S bond in which there is interaction of a sulfur sp2 *hybrid orbital with a bonding combination of empty orbitals on the two copper atoms. In solution the [CuSC6H3(CH(R')NMe2)-2-R"-3]3 complexes remain trimeric but exist as two conformers that are in equilibrium through inversion at the bridging sulfur atoms. and 13C NMR studies reveal that the ratio of these two conformers can be influenced by changing R' and R" in the arenethiolate ligand. The low free activation energy barrier (AG* = ±50 kj/mol) for sulfur inversion is explained by a new mechanism which is based on a rotation (wagging) process around the axis through the sp2 hybrid orbital in the electron-deficient Cu2S unit. Evidence for the occurrence of separate intermolecular exchange processes is presented.

Formation of meso-1,2-Bis(dimethylamino)-1,2-diphenylethane by Oxidative C-C Coupling Reaction

“…Addition of lithiated N, N-dimethylbenzylamine to a suspension of sulfur in THF at −78 • C and acid workup gives 2-((N, N-dimethylamino)methyl)thiophenol in moderate to good yields, as was reported in the literature [8,10] and confirmed in our own syntheses (see Scheme 1). When the reaction was carried out in such (7) 116.1(3) 116.7…”

“…Several o-lithiated benzyl derivatives were successfully converted to the respective thiols [8], (di)selenides or (di)tellurides [9]. We report a hitherto unknown α-deprotonation of N,N-dimethylbenzylamine by nBuLi and the oxidative dimerization of the resulting anion to give meso-1,2-bis(dimethylamino)-1,2-diphenylethane.…”

Efficient recycling of fluorous versions of highly enantioselective S,N-chelated zinc aminoarene thiolate catalysts for the 1,2-addition of diethylzinc to benzaldehydes

“…The products 3a-3c were obtained in quantitative yield (see Scheme 2) [9]. Crystallization from hexane gave novel 3a as a colorless solid that was characterized by elemental analysis, 1 H and 13 C NMR spectroscopy.…”

Synthesis of Aminoarenethiolato‐Copper(I) Complexes

“…The sulfur atom of each of the arenethiolate ligands bridges two copper atoms while the trigonal coordination geometry at each copper atom is attained by intramolecular N-Cu coordination. 7 These copper-aminoarenethiolates have already been tested as catalyst (precursors) in allylic substitution, 9 1,4-10 and 1,6-11 addition reactions, aromatic N- 12 and O-13 arylation reactions, and have shown excellent catalytic properties (Figure 2).…”