Out-of-plane interactions in parallel-planar copper(II) dimers. Structure and magnetic properties of dibromobis(2-methylpyridine)copper(II)

Abstract

Dibromobis(2-mbthylpyridinb)copper(II) (CO) , although not statistically significant, is in accord with the aforementioned acceptor capabilities of the mercury atom. Within each Mn(CO)o group, the average Cax • • • Ceq nonbonding distance is 2.712 Á. This value is slightly longer than the corresponding value of 2.64 Á observed in Mn2(CO)io41 but is in agreement with the greater angular distortion and greater metal-carbon bond lengths present in Hg-[Mn(CO),],.The mean C-0 distance of 1.154 (10) Á agrees well" with the value of 1.156 Á in Mn2(CO)io and also with values observed in other transition metal carbonyls. There is no significant difference between the axial and equatorial C-0 distances in this compound, which is consistent with the known insensitivity of the C-0 bond length to changes in bond order in the range 2-3. The Mn-C-0 angles have an average value of 178°; thus there is no significant distortion from linearity due to intermolecular packing forces and/or electronic effects.The closest intermolecular contacts (Table III) of range 3.1-3.4 Á indicate no abnormal intermolecular forces.69

Copper(II) complexes of 2-amino-5-chloro-3-fluoropyridine: syntheses and magnetic properties of (3,5-FCAP)2CuX2 and (3,5-FCAPH)2CuX4

“…In the syn conformation, the amino substituents effectively block one face of the Cu(II) ion, preventing adjacent molecules from approaching each other on that side, thus limiting the bi-halide bridging to formation of a dimeric structure rather than a chain. This has been observed previously in related structures [4,11,41]. In 1, the fluorine substituents do not participate in halogen or hydrogen bonding, so the halogen and hydrogen bonds made by the fluorine substituents in 2 may influence the change from anti to syn.…”

“…Substituent position on the ring is also important as it affects hydrogen bond formation and other intermolecular interactions [10]. Methyl [11][12][13], amino [14][15][16], and other [1,17] groups have been used as substituents on pyridine rings in Cu(II) complexes that have been studied previously. These substituents modify the packing structure through the respective size of the substituent, through the introduction of possible hydrogen bond donors and acceptors into the complex, and through increased or decreased electron density in the pyridine ring.…”

Magnetostructural Characterization of Oxalamide Dihalo‐Bridged Copper Dimers: Intra‐ and Interdimer Interactions Studied by Single‐Crystal Electron Spin Resonance Spectroscopy

“…This results in very weak overlap of the orbitals from ligands, which mediate the exchange. [13,38,[46][47][48][49] In the simulations, we assumed that the crystal structures did not change with temperature and the g parameters were not allowed to change with temperature. Indeed, X-ray diffraction at 100 Ks hows that there is no significant temperaturedependentc hange in the structures.…”

Synthesis, Spectroscopy, and Magnetic Characterization of Copper(II) and Cobalt(II) Complexes with 2-Amino-5-bromopyridine as Ligand

“…One such system of potential importance is that formed by copper(II) halides with pyridine and substituted pyridines [3]. Small lowmolecular-weight copper(II) coordination complexes with N-donor ligands have frequently been used to model the active site in copper proteins with the aim of obtaining insight into the correlation between structure and the spectroscopic and magnetic behavior [4][5][6][7]. Cobalt(II) complexes are important in biology mainly because of coenzyme B 12 [8].…”