Syntheses and structures of Ag(I) complexes containing 1,4-bis(4,5-dihydro-2-oxazolyl)benzene

Synthesis of Silver(I) and Gold(I) Complexes Containing Enantiopure Pybox Ligands. First Assays on the Silver(I)-Catalyzed Asymmetric Addition of Alkynes to Imines

Dinuclear complexes [Ag2(CF3SO3){(S,S)-(i)Pr-pybox}2][CF3SO3] (1), [Ag2(R-pybox)2][X]2 [R-pybox = 2,6-bis[4-(S)-isopropyloxazolin-2-yl]pyridine (S,S)-(i)Pr-pybox and X = PF6 (2) and BF4 (3); R-pybox = 2,6-bis[(3aS,8aR)-8,8a-dihydro-3aH-indeno[1,2-d]oxazol-2-yl]pyridine (3aS,3a'S,8aR,8a'R)-indane-pybox and X = CF3SO3 (4)], [Ag2{(S,S)-(i)Pr-pybox}{(3aS,3a'S,8aR,8a'R)-indane-pybox}][CF3SO3]2 (5), and [Ag2(R-pybox)3][X]2 [R-pybox = (3aS,3a'S,8aR,8a'R)-indane-pybox and X = CF3SO3 (10), SF6 (11), and PF6 (12)] as well as mononuclear complexes [Ag(R-pybox)2][X] [R-pybox = (S,S)-(i)Pr-pybox and X = SbF6 (6), PF6 (7), and BF4 (8); R-pybox = (3aS,3a'S,8aR,8a'R)-indane-pybox) and X = BF4 (9)] have been prepared by the reaction of the corresponding silver salts and pybox ligands using the appropriate molar ratio conditions. The first gold(I)/pybox complex [Au6Cl4{(S,S)-(i)Pr-pybox}4][AuCl2]2 (13) has been synthesized by the reaction of [AuCl{S(CH3)2}] and (S,S)-(i)Pr-pybox (1:1 molar ratio) in acetonitrile. The structures of the dinuclear (1, 4, 5, 10, and 11) and mononuclear (6 and 9) silver complexes and the hexanuclear gold complex 13 have been determined by single-crystal X-ray diffraction analysis. These studies have been complemented with a solution-state study by NMR spectroscopy, which included structure elucidation, variable-temperature measurements, and diffusion studies using diffusion-ordered spectroscopy (DOSY; for complexes 1, 4, 10, and 12). Complexes 1, 2, 4, and 10 have been assayed as catalysts in the asymmetric addition of phenylacetylene to N-benzylideneaniline.

Tetra-kis[μ-1,3-bis-(4,5-dihydro-1,3-oxazol-2-yl)benzene-κ(2)N:N']tris-ilver(I) tris-(hexa-fluoridophosphate)

In the title compound, [Ag₃(C₁₂H₁₂N₂O₂)₄](PF₆)₃, one Ag^I ion, lying on a twofold rotation axis, is coordinated by four N atoms from four 1,3-bis­(4,5-dihydro-1,3-oxazol-2-yl)benzene (L) ligands in a distorted tetra­hedral geometry and the other Ag^I ion is coordinated by two N atoms from two L ligands in a bent arrangement [N—Ag—N = 169.03 (17)°]. Two L ligands adopt a syn conformation, while the other two adopt an anti conformation. They bridge adjacent Ag^I ions, forming a trinuclear complex. One of the PF₆⁻ anions is half-occupied, with the P atom located on a twofold rotation axis. The PF₆⁻ anions link the complex mol­ecules via Ag⋯F inter­actions [2.80 (2) and 2.85 (2) Å] into a polymeric chain along [100].

catena-Poly[[silver(I)-μ-1,2-bis-(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)ethane-κ(2)N:N'] perchlorate hemihydrate]

In the title coordination polymer, {[Ag(C(12)H(20)N(2)O(2))]ClO(4)·0.5H(2)O}(n), the Ag(I) cation is coordinated by two N atoms from two 1,2-bis-(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)ethane (L) ligands in a nearly linear geometry [N-Ag-N = 171.07 (8)°]. The L ligand bridges adjacent Ag(+) cations, forming a polymeric chain running along the c axis. The lattice water mol-ecule is situated on a twofold rotation axis, and links to the perchlorate anion via an O-H⋯O hydrogen bond. The long Ag⋯O separation of 3.200 (4) Å indicates a weak inter-action between the perchlorate anion and the Ag(I) cation. Weak C-H⋯O hydrogen bonding occurs between the chain and the lattice water mol-ecule and between the chain and perchlorate anions. Both five-membered rings of the L ligand display envelope conformations; in one five-membered ring, the flap C atom is disordered on opposite sides of the ring with occupancies of 0.65 and 0.35.

catena-Poly[[bis-(nitrato-κO)copper(II)]-μ-1,4-bis-(4,5-dihydro-1,3-oxazol-2-yl)-benzene-κN:N']

In the title coordination polymer, [Cu(NO(3))(2)(C(12)H(12)N(2)O(2))](n), the Cu(II) ion, situated on an inversion center, is coordinated by two O atoms from two nitrate anions and two N atoms from two 1,4-bis-(4,5-dihydro-1,3-oxazol-2-yl)benzene (L) ligands in a distorted square-planar geometry. Each L ligand also lies across an inversion center and bridges two Cu(II) ions, forming a polymeric chain running along the [101] direction. The three O atoms of the nitrate group are disordered over two positions in a 3:2 ratio.