Tetra-, Di-, and Mononuclear Copper(I) Complexes Containing (S,S)-ⁱPr-pybox and (R,R)-Ph-pybox Ligands

Abstract

Tetranuclear [Cu4I4{(S,S)-iPr-pybox}2] (1) and dinuclear [Cu2Cl-{(S,S)-iPr-pybox}2][CuCl2] (2) copper(I) complexes have been synthesized by reaction of iPr-pybox with CuI and CuCl, respectively. Furthermore, dinuclear [Cu2(R-pybox)2][PF6]2 [R-pybox = (R,R)-Ph-pybox (3), (S,S)-iPr-pybox (4)] and mononuclear complexes [Cu(R-pybox)2][PF6] [R-pybox = (R,R)-Ph-pybox (5), (S,S)-iPr-pybox (6)] have been prepared by reaction of [Cu(MeCN)4][PF6] and the corresponding pybox. The structures of complexes 1-3 have been determined by X-ray diffraction analyses.

Asymmetric [4+2] Annulation of C1 Ammonium Enolates with Copper‐Allenylidenes

“…On the basis of our experimental results,t he previous reports by the groups of Nishibayashi, [10d] Xiao, [14] Hu, [7b] and the cryatallographic structure of [Cu(CH 3 CN) 4 ]PF 6 /(S)-L1, [18] ap lausible transition state to account for the observed stereochemistry is proposed (Scheme 3). Thed inuclear cooper complex [18] might play ad ual role in which one copper participated in the decarboxylation of 1a to generate the copper-allenylidene complex, and the other acts as ac ounterion bonded to the C1 ammonium Z-enolate. [14] Thep ropargylation step favors nucleophilic attack to the Siface of the copper-allenylidene complex via TS-Ia,a nd subsequent lactamization (Scheme 2) gives the experimentally observed (R,R)-3aa as the major isomer.…”

Enantioselective additions of copper acetylides to cyclic iminium and oxocarbenium ions

“…This lack is likely due to the multiple possibilities for copper acetylide structures (monomer, dimer, dicopper acetylide, etc.) [ 18 , 59 – 65 ]. Careful mechanistic studies to elucidate the structures of chiral copper acetylides and to provide stereochemical rationale for the enantioselectivities of these reactions is needed to enable further development of catalysts in this important area.…”

Cu(I)···H–C Bonding in Cu(2,3-Diphenylquinoxaline)ClO4

“…Agostic-like interactions are thus more reasonable in 16-electron Cu(I) species, such as 1. A literature search uncovered a limited number of close C-HÁÁÁM interactions for Cu(II) [30][31][32], Cu(I) [33][34][35][36], Ag(I) [37][38][39][40][41], and Au(I) [42]. The relevant structural parameters in analyzing the nature of C-HÁÁÁM include MÁÁÁH, MÁÁÁC, and C-H distances and MÁÁÁH-C angle.…”

“…The relevant structural parameters in analyzing the nature of C-HÁÁÁM include MÁÁÁH, MÁÁÁC, and C-H distances and MÁÁÁH-C angle. Some data for C-HÁÁÁCu(I) and C-HÁÁÁCu(II) examples in which CuÁÁÁC is less than 2.9 Å and/or CuÁÁÁH is less than 2.5 Å are provided in Table 3 [30][31][32][33][34][35][36]. Copper(I)-olefin complexes (some of which show highly skewed distances in which the Cu atom is closer to one C) have been excluded.…”

“…closer CuÁÁÁH than CuÁÁÁC contact, and relatively large CuÁÁÁH-C angle. These include both copper(I) and copper(II) complexes: [Cu 2 (R-pybox) 2 ][PF 6 ] 2 Áacetone [33], Cu(cyclodecane-1,3-dionate) 2 [30], Cu(Hceph) 2 [32], and [Cu(HPz 00 )(g 1 -H 2 CPz 00…”