Cyanide Single-Molecule Magnets Exhibiting Solvent Dependent Reversible "On" and "Off" Exchange Bias Behavior.

The syntheses, structures, and magnetic properties of four new complex salts, (PPN){[Mn(III)(salphen)(MeOH)]2[M(III)(CN)6]}·7MeOH (Mn2M·7MeOH) (M = Fe, Ru, Os and Co; PPN(+) = bis(triphenylphosphoranylidene)ammonium cation; H2salphen = N,N'-bis(salicylidene)-1,2-diaminobenzene), and a mixed metal Co/Os analogue (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH were undertaken.

Record antiferromagnetic coupling for a 3d/4d cyanide-bridged compound.

The pentanuclear compound [V(II)(tmphen)2]3[Mo(III)(CN)6]2 (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline) exhibits a record antiferromagnetic exchange coupling constant of J(V-Mo) = -114 cm(-1). This is the first example of a heterobimetallic cyanide compound with such strong magnetic coupling.

Variations in topology and magnetic properties of hepta- and octacyanometallates of molybdenum with manganese(II).

Treatment of [Mn(dpop)(H2O)2]Cl2 (dpop = 2,13-dimethyl-3,6,9,12,18-pentaazabicyclo-[12.3.1]octadeca-1(18),2,12,14,16-pentaene) with K4[Mo(CN)7]·2H2O under varied synthetic conditions afforded four different compounds: {[Mn(dpop)]4[(dpop)Mn(H2O)]2[Mo(III)(CN)7]3·27H2O}n (1), {[(dpop)Mn(H2O)][Mo(III)(CN)7][Mn(dpop)]3[Mo(IV)(CN)8]·29H2O}n (2), {[(dpop)Mn(H2O)]2[Mo(IV)(CN)8]2[Mn(dpop)]4[Mo(III)(CN)7]·12H2O}n (3), and [(dpop)Mn(H2O)]2[Mo(IV)(CN)8]·9H2O (4).

Dimensionality selection in a molecule-based magnet.

Gaining control of the building blocks of magnetic materials and thereby achieving particular characteristics will make possible the design and growth of bespoke magnetic devices. While progress in the synthesis of molecular materials, and especially coordination polymers, represents a significant step towards this goal, the ability to tune the magnetic interactions within a particular framework remains in its infancy. Here we demonstrate a chemical method which achieves dimensionality selection via preferential inhibition of the magnetic exchange in an S=1/2 antiferromagnet along one crystal direction, switching the system from being quasi-two- to quasi-one-dimensional while effectively maintaining the nearest-neighbor coupling strength.

Ag(nic)2 (nic = nicotinate): a spin-canted quasi-2D antiferromagnet composed of square-planar S = 1/2 Ag(II) ions.

Square-planar S = 1/2 Ag(II) ions in polymeric Ag(nic)(2) are linked by bridging nic monoanions to yield 2D corrugated sheets. Long-range magnetic order occurs below T(N) = 11.8(2) K due to interlayer couplings that are estimated to be about 30 times weaker than the intralayer exchange interaction.

Structural, electronic, and magnetic properties of quasi-1D quantum magnets [Ni(HF2)(pyz)2]X (pyz = pyrazine; X = PF6(-), SbF6(-)) exhibiting Ni-FHF-Ni and Ni-pyz-Ni spin interactions.

[Ni(HF(2))(pyz)(2)]X {pyz = pyrazine; X = PF(6)(-) (1), SbF(6)(-) (2)} were structurally characterized by synchrotron X-ray powder diffraction and found to possess axially compressed NiN(4)F(2) octahedra. At 298 K, 1 is monoclinic (C2/c) with unit cell parameters, a = 9.9481(3), b = 9.

Characterization of the antiferromagnetism in Ag(pyz)2(S2O8) (pyz = pyrazine) with a two-dimensional square lattice of Ag2+ ions.

X-ray powder diffraction and magnetic susceptibility measurements show that Ag(pyz)(2)(S(2)O(8)) consists of 2D square nets of Ag(2+) ions resulting from the corner-sharing of axially elongated AgN(4)O(2) octahedra and exhibits characteristic 2D antiferromagnetism. Nevertheless, mu(+)SR measurements indicate that Ag(pyz)(2)(S(2)O(8)) undergoes 3D magnetic ordering below 7.8(3) K.

Strong H...F hydrogen bonds as synthons in polymeric quantum magnets: structural, magnetic, and theoretical characterization of [Cu(HF2)(pyrazine)2]SbF6, [Cu2F(HF)(HF2)(pyrazine)4](SbF6)2, and [CuAg(H3F4)(pyrazine)5](SbF6)2.

Three Cu(2+)-containing coordination polymers were synthesized and characterized by experimental (X-ray diffraction, magnetic susceptibility, pulsed-field magnetization, heat capacity, and muon-spin relaxation) and electronic structure studies (quantum Monte Carlo simulations and density functional theory calculations). [Cu(HF(2))(pyz)(2)]SbF(6) (pyz = pyrazine) (1a), [Cu(2)F(HF)(HF(2))(pyz)(4)](SbF(6))(2) (1b), and [CuAg(H(3)F(4))(pyz)(5)](SbF(6))(2) (2) crystallize in either tetragonal or orthorhombic space groups; their structures consist of 2D square layers of [M(pyz)(2)](n+) that are linked in the third dimension by either HF(2)(-) (1a and 1b) or H(3)F(4)(-) (2). The resulting 3D frameworks contain charge-balancing SbF(6)(-) anions in every void.

Bis(di-2-pyridyl-methanediol)copper(II) dihydrogentrifluoride: a structural and spectroscopic study of the H2F3 - anion in a complex salt.

The H(2)F(3)(-) anion in mononuclear [Cu(dpd)(2)][(H(2)F(3))(2)] (dpd = di-2-pyridyl-methanediol) exists as a HF(2)(-)/HF adduct as evidenced by infrared spectroscopy and X-ray crystallography.