Reaction of the title ligand (L) with copper salts leads to the formation of three principal series of compounds, LCu2X3(OH)•H2O (X = Cl, Br), LCu2(RCO2)3, and LCu2(RCO2)4, where RCO2 represents various aliphatic and aromatic carboxylate species. Magnetic data, electronic spectroscopic data both at room temperature and at −196 °C, infrared spectra, and microanalytical data are correlated to reveal that these complexes contain a binuclear copper-copper system in which the copper atoms are 5-coordinate and square pyramidal. Brief details are presented of an X-ray structural analysis of the chloride complex confirming the structure proposed.The ligand forms complexes both in its neutral form and in an anionic deprotonated form. The ultraviolet spectra of the complexes distinguish these modes of bonding. The electronic spectra are discussed in terms of the 5-coordinate square pyramidal copper chromophore deemed to be present. In the complex L2Cu, the copper atom has a trigonally distorted 6-coordinate environment with tridentate anionic ligand.

High-frequency electron paramagnetic resonance (EPR) studies of the antiferromagnetic Mn-[3×3] molecular grid clearly reveal a breaking of the ∆S = 0 selection rule, providing direct evidence for the mixing of spin wavefunctions (S-mixing) induced by the comparable exchange and magnetoanisotropy energy scales within the grid. This finding highlights the potential utility of EPR for studies of exchange splittings in molecular nanomagnets, which is normally considered the sole domain of inelastic neutron scattering, thereby offering improved sensitivity and energy resolution. PACS numbers: 33.15.Kr, 71.70.-d, 75.10.JmThe synthesis of ordered crystalline arrays (ensembles) of nominally identical magnetic molecules has enabled unprecedented insights into quantum magnetization dynamics at the nanoscale, leading to exciting discoveries such as the quantum interference associated with the coherent rotation (tunneling) of a large spin [1]. The molecular approach is particularly attractive due to the highly ordered and monodisperse nature of the molecules in the solid state, and because one can systematically vary many key parameters that influence the quantum behavior of a magnetic molecule, e.g., the total spin, symmetry, etc. The magnetism of these molecules can be described quite generally by the microscopic spin Hamiltonian [2]

The reactions of MX,(M = As, Sb; X = C1, Br) with [Fe(CO),(n-C,H,)], in CH,Cl, solution give ionic derivatives containing the [X,M (Fe(CO),(n-C,H,) },I+ cation as well as the neutral compounds X,AsFe(CO), (n-C,H,), while similar reactions of SbX, and BiX, (X = C1, Br, I) in C,H, or tetrahydrofuran yield X,MFe ( C0),(n-C5H5) and XSb [Fe ( CO),(n-C,H,)],.

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Tetrahedral and octahedral cobalt(II), and square and octahedral nickel(I1) complexes of 1,2-bis(2'-imidazolin-2'-yl)benzene, 1,2-bis(2'-imidazolin-2'-yl)ethane, and some imidazoline ring methyl substituted ligands are reported. The structures are confirmed by three X-ray structural analyses, magnetism, and electronic and vibrational (conventional and far i.r.) spectroscopy. Both cis and trans octahedral complexes of the type M(ligand)z(NCS)z [M = Co(II), Ni(II)] have been characterized, and none of these exhibit splitting of the v(CN)(NCS) absorption in the i.r. spectrum at room temperature. Low temperature studies reveal splitting of the v(CN) band in the cis isomers. Both 13C and I5N satellite absorption is identified. The delocalization of the double bond in the imidazoline rings in these complexes is discussed in terms of the i.r. and X-ray data.Canadian Journal of Chemistry, 48, 3076 (1970) We report here the metal complexing ability calibrant. The U.V. spectra were recorded with a Cary 14 of some novel bidentate ligands containing spectrometer and molecular weight data with a modified Gallenkamp Model 7665K semi-micro ebulliometer, imidazoline rings.the coordination calibrated with azobenzene and with benzoic acid. Infrachemistry of imidazole and its derivatives has red and far i.r. data were obtained with a Beckman IR 12 been extensively investigated (1, 2), studies of its spectrometer, and magnetic susceptibilities, via the Gouy dihydro derivative are restricted to the chemistry method with an Alpha 4 in. magnet calibrated with of 2,2,-bi-2-imidazoline (3). since the dihydro mercury cobalt tetrathiocyanate. Low temperature electronic and vibrational data were obtained with a Beckman ligand is somewhat simpler than imidazole, being V L T -~ Variable Temperature Cell, with quartz (elecnon-aromatic, it was thought that a study of its tronic), o r NaCl (i.r.) windows. Microanalyses were metal complexing ability might prove rewarding. substituted derivative (4, LME) were synthesized TO 1,3-diiminoisoindoline (6) (7.25 g, 0.05 mole) disby the phosphorus pentasulfide catalyzed reaction solved in boiling absolute ethanol, was added ethyleneof ethylenediamine (or 1,2-propanediamine) with diamine (6.2 g, 0.1 mole) and the mixture refluxed until phthalodinitrile or succinonitrile, a standard evolution of ammonia had ceased. The bulk of the solvent was removed by distillation at reduced pressure until route for the preparation Of imidazolines (4). crystallization occurred. The white crystalline product The ethane derivative LE has been reported (5) (6.1 g, 60% yield) was recrystallized from benzene. T h e but the other ligands were previously unknown. pure product melted at 174-175". Reaction of the parent ligands with cobalt and Method B (Based on (7)) nickel salts in alcohol led to the isolation of a 0-Dicyan~benzene (6.4 g, 0.05 mole), ethylenediamine series of square, tetrahedral, and octahedral (6.2 g, 0.1 mole), and a catalytic amount of phosphorus pentasulfide (20 mg) were mixed together. Upon applicacomp...