Structural, Magnetic and Spectroscopic Characterization of Novel Di-μ-carboxylato-Bridged Binuclear Copper(II) Complexes with 1,10-Phenanthroline

Abstract

Bis(μ-carboxylato-O,O′)-diaquabis(1,10-phenanthroline)dicopper(II) dinitrate tetrahydrates, [Cu(RCOO)(phen)(H2O)]2(NO3)2·4H2O, where R=H, CH3, and (CH3)3C, were prepared and characterized by elemental analyses, electronic spectra, magnetic susceptibilities, and X-ray structure analysis. The magnetic susceptibility data conform to the usual dimer equation. The −2J values are 125 cm−1 for formate, 86 cm−1 for acetate, and 99 cm−1 for 2,2-dimethylpropanoate. The crystal structures of [Cu(HCOO)(phen)(H2O)]2(NO3)2·4H2O (1) and [Cu(CH3COO)(phen)(H2O)]2(NO3)2·4H2O (2) were determined by the single-crystal X-ray diffraction method. The crystallographic data are: Compound 1, monoclinic, I2⁄a, a=18.850(2), b=9.775(2), c=17.752(2) Å, β=99.03(1)°, V=3230.4(8) Å3, Z=4, R=0.055 for 2511 observed unique reflections; Compound 2, monoclinic, C2⁄c, a=18.563(4), b=14.272(5), c=14.126(3) Å, β=106.72(2)°, V=3584(2) Å3, Z=4, R=0.082 for 2092 reflections. The complexes consist of dimeric [Cu(RCOO)(phen)(H2O)]22+)] cations with five-coordinated copper ions linked by two carboxylato ions in a syn-syn bridging arrangement. The Cu···Cu distances are 3.103(2) Å for 1 and 3.063(3) Å for 2.

Copper(II) Complexes of N‐Methylated Derivatives of ortho‐ and meta‐Xylyl‐Bridged Bis(1,4,7‐triazacyclononane) Ligands: Synthesis, X‐ray Structure and Reactivity as Artificial Nucleases

“…This motif is rare amongst the various binding motifs that have been reported in the literature for copper(II)-acetato complexes (see Figure 2). Tokii et al [30] reported the same binding mode in a copper(II) complexes with 1,10-phenanthroline ligands. Their reported Cu···Cu separation of 3.063(3) Å is much shorter than that found in C m due to the π-π interaction between the chelating phen ligands on the two copper centres forming the dinuclear complex.…”

Exchange Coupling in Carboxylato-Bridged Dinuclear Copper(II) Compounds: A Density Functional Study

“…[15,102,104] To consider the effect of this structural feature on the coupling constant we have displaced the four water molecules that replace two carboxylato bridges (7) by increasing the O b -Cu-O t angle to 1808 and moving the axial…”

“…[15,102,104] Replacement of the four water molecules by ammonia decreases the strength of the antiferromagnetic coupling. For acetato-bridged compounds the coupling constant is reduced by 20 cm À1 , from À 179 to À 159 cm À1 .…”

Organic–Inorganic Hybrids Based on Novel Bimolecular [Si2W22Cu2O78(H2O)]12− Polyoxometalates and the Polynuclear Complex Cations [Cu(ac)(phen)(H2O)]nn+ (n=2, 3)

“…Experimental data were used as the starting point in the global optimizations of [SiW 12 3 + (C 1 , S = 3 = 2 ) cationic complexes. For the cationic complexes, the standard 6-31G(d) [31] basis has been chosen for all atoms.…”

“…[12] It comprises two squarepyramidal Cu atoms bridged by two acetate anions in a synsyn fashion with a CuÀCu length of 3.06 . Each basal plane is formed by two phenanthroline N atoms and two acetate O atoms, the apical position being occupied by a water molecule (Figure 3a).…”