Structural and Magnetic Studies of Dimeric Copper(II) 2,2-Diphenylpropanoato and Triphenylacetato Complexes with Oxygen-Donor Ligands. The Cage Geometry of Dimeric α-Phenyl Substituted Copper(II) Carboxylates

Abstract

The syntheses, structures, and magnetic properties of copper(II) carboxylates with bridging α-phenyl substituted carboxylato ligands and unidentate oxygen-donor ligands are reported: Cu2 (O2CCPh2Me)4(acetone)2 (1), triclinic , a = 15.441(4), b = 15.602(4), c = 12.790(2) Å, α = 106.52(2), β = 92.11(2), γ = 96.38(2)°, V = 2928(1) Å3, Z = 2, −2J = 352 cm−1; [Cu2(O2CCPh2Me)4(H2O)2]·H2O (2), triclinic , a = 13.895(2), b = 14.717(2), c = 7.318(1) Å, α = 95.67(1), β = 101.71(1), γ = 68.12(1)°, V = 1359.3(4) Å3, Z = 1, −2J = 344 cm−1; [Cu2(O2CCPh2Me)4(EtOH)2]·EtOH (3), monoclinic P21/c, a = 26.927(5), b = 9.152(3), c = 26.881(5) Å, β = 115.02(1)°, V = 6003(2) Å3, Z = 4, −2J = 347 cm−1; [Cu2(O2CCPh3)4(Ph3CCO2H)2]·CH2Cl2 (4), monoclinic P21/c, a = 18.133(8), b = 23.046(7), c = 25.013(7) Å, β = 101.01(3)°, V = 10268(5) Å3, Z = 4; [Cu2(O2CCPh3)4(H2O)2]·4H2O (5a), tetragonal , a = 18.451(6), c = 10.703(7) Å, V = 3643(3) Å3, Z = 2; [Cu2(O2CCPh3)4(H2O)2]·2H2O (5b), tetragonal , a = 18.224(2), c = 10.776(5) Å, V = 3578(1) Å3, Z = 2, −2J = 292 cm−1; and Cu2(O2CSiPh3)4(EtOH)2 (6), monoclinic C2/c, a = 21.811(3), b = 17.366(3), c = 21.221(4) Å, β = 91.19(1)°, V = 8036(2) Å3, Z = 4, −2J = 1193 cm−1. The factors which influence the cage and coordination sphere geometry in dimeric α-phenyl substituted copper(II) carboxylates are discussed based on the above structures and the reported structures with unidentate nitrogen- and oxygen-donor ligands. In 4 and 5, intramolecular steric effects between the bulky triphenylacetato ligands result in a considerable distortion of the cage geometry. The distortion of the coordination sphere geometry around copper(II) in the complexes from square pyramidal toward trigonal bipyramidal reduces the spin-exchange interaction.

A very bulky carboxylic perchlorotriphenylmethyl radical as a novel ligand for transition metal complexes. A new spin frustrated metal system

“…3(b)) 10 modified to take into account intermolecular interactions (q = 21.7 K) in the molecular field approximation. The value of the body/body interaction, J 13 = 2350 K, is within the range of those previously reported for the same kind of interaction in other paddle-wheel Cu(II) dimers, 11 whereas the value of the wing-tip/body interaction, J = 221.3 K, is similar to that previously reported for the Cu(II)/PTMMC radical interaction in complex 1. The fact that both exchange coupling parameters, J and J 13 , are negative indicates that any two neighboring spins tend to align antiferromagnetically.…”

Synthesis, structural and magnetic properties of a series of copper(ii) complexes containing a monocarboxylated perchlorotriphenylmethyl radical as a coordinating open-shell ligand

“…The resulting expression, modified to take into account intermolecular interactions (θ) in the molecular field approximation, was then used to least-squares fit the experimental data of 4. Fixing the evaluated g = 2.01, the best fit was obtained for J = Ϫ21.3 K, J 13 = Ϫ350.0 K and θ = Ϫ1.7 K. The value of the body/body [copper()-copper()] interaction, J 13 = Ϫ350 K, is within the range of those previously reported for the same kind of interaction in other paddle-wheel Cu() dimers, 20 whereas the value of the wing-tip/body [copper()-radical interaction], J 13 = Ϫ21.3 K, is similar to that previously reported for the Cu()-PTMMC radical interaction in complexes 1-3. The fact that both exchange coupling parameters, J and J 13 , are negative indicates that any two neighboring spins tend to align antiferromagnetically.…”

Structurally Diverse Copper(II)−Carboxylato Complexes: Neutral and Ionic Mononuclear Structures and a Novel Binuclear Structure

“…The other two carboxylato ligands are bound to the Cu(II) atoms in a unidentate mode, while the two bipyam neutral ligands are coordinated to the copper atoms in a bidentate fashion. The present mode of coordination is unique (Table ), − and the Cu···Cu distance of 4.50 Å falls in the range between 4.0 and 5.0 Å, for which no other examples have been reported. Thus, the present compound provides an opportunity to study the magnetic behavior and the EPR spectra of a Cu···Cu system separated by 4.50 Å and having only carboxylato bridges.…”

“…51 s [Cu2L(OAc)2] + .55 t More than 200 examples are available in the literature. Some representative compounds are given here: catena-tetrakis[µ-(2-chlorophenoxy)ethanoato-O,O′]dicopper(II), [{Cu2(O2CCH2OC6H4Cl-2)4}n];56 [Cu2(O2CCPh3)4(H2O)2]‚2H2O;57 [Cu2(O2CCPh2Me)4(H2O)4]‚H2O 57. u Tetrakis(µ-1-phenylcyclopropane-1-carboxylato-O,O′)bis(ethanol-O)dicopper(II);42 [Cu2(PCIBA)4(2-aminopyrimidine)2]2, HPCIBA ) 2-methyl-2-(4-chlorophenoxy)propanoic acid.…”