Song-Song Bao

Enhancing proton conduction in 2D Co-La coordination frameworks by solid-state phase transition.

We report that a new 2D 3d-4f phosphonate [Co(III)La(III)(notpH)(H2O)6]ClO4·5H2O (CoLa-II) can undergo a phase transition above 45 °C and 93% relative humidity, resulting in [H3O][CoLa(notp)(H2O)4]ClO4·3H2O (CoLa-III). The transition is accompanied by the release of the proton from intralayer to interlayer, and thus the proton conductivity of the material is increased by 1 order of magnitude.

Homochiral Lanthanide Phosphonates with Brick-Wall-Shaped Layer Structures Showing Chiroptical and Catalytical Properties

Based on enantiopure S- or R-(1-phenylethylamino)methylphosphonic acid (pempH(2)), homochiral lanthanide phosphonates (S)-[Ln(pempH)(NO(3))(2)(H(2)O)(2)] (S-Ln) and (R)-[Ln(pempH)(NO(3))(2)(H(2)O)(2)] (R-Ln) (Ln = Eu, Tb, Ho) are obtained successfully. All six compounds are isostructural, showing chiral brick-wall-shaped layer structures. They are all optically active, exhibiting second harmonic generation responses 0.7 times that of urea. The Eu and Tb compounds display strong red and green luminescent properties, respectively, with long luminescent lifetimes at the level of milliseconds. The catalytic properties of the dehydrated S-Tb are studied.

A layered erbium phosphonate in pseudo-D5h symmetry exhibiting field-tunable magnetic relaxation and optical correlation

A layered erbium(III) phosphonate compound, [Er(notpH4)(H2O)]ClO4·3H2O (1), in which the Er(III) ion has a pseudo-D5h symmetry exhibits field tunable multiple magnetic relaxation. The near-IR emission spectrum of 1, excited at 1064 nm (Nd:YAG laser), provides a direct probe of the crystal field splitting correlated to the magnetic data.

Solvent Responsive Magnetic Dynamics of a Dinuclear Dysprosium Single‐Molecule Magnet

A new dysprosium(III) phosphonate dimer {Dy(notpH4)(NO3)(H2O)}2·8H2O (1) [notpH6=1,4,7-triazacyclononane-1,4,7-triyl-tris(methylenephosphonic acid)] that contains two equivalent Dy(III) ions with a three-capped trigonal prism environment is reported. Complex 1 can be transformed into {Dy(notpH4)(NO3)(H2O)}2 (2) in a reversible manner by desorption and absorption of solvent water at ambient temperature. This process is accompanied by a large dielectric response. Magnetic studies reveal that both 1 and 2 show thermally activated magnetization relaxation as expected for single-molecule magnets. Moreover, the magnetic dynamics of the two compounds can be manipulated by controlling the number of solvent molecules at room temperature.

Polymorphism in homochiral zinc phosphonates.

This paper reports four homochiral zinc phosphonates, alpha-(S)-[Zn 2(pemp)(pempH)Cl] (1), alpha-(R)-[Zn 2(pemp)(pempH)Cl] (2), beta-(S)-[Zn 2(pemp)(pempH)Cl] (3), and beta-(R)-[Zn 2(pemp)(pempH)Cl] (4) [pempH 2 = (1-phenylethyl)amino]methylphosphonic acid]. Both 1 and 2 are enantiomers, crystallizing in an orthorhombic P2(1)2(1)2(1) space group, while 3 and 4 are polymorphic phases of 1 and 2, respectively, crystallizing in a monoclinic P2(1) space group. The polymorphism is induced by temperature or additional organic molecules.

Tuning the coordination geometries and magnetic dynamics of [Ln(hfac)4](-) through alkali metal counterions.

Four lanthanide compounds with formulas [Cs{Dy(hfac)4}] (1), [Cs{Er(hfac)4}] (2), [K{Dy(hfac)4}] (3), and [K{Er(hfac)4}] (4) (hfac = hexafluoroacetylacetone) are reported. Compounds 1 and 2 crystallize in the orthorhombic Pbcn space group, while 3 and 4 are in the triclinic P1̅ space group. All display chain structures in which the mononuclear [Ln(hfac)4](-) anions are linked by alkali metal ions. However, the coordination geometries around the Ln atoms are quite different depending on the cation. They adopt a distorted dodecahedron with pseudo-D2d symmetry in the cesium compounds 1 and 2, while a distorted square-antiprism with pseudo-D4d symmetry is adopted in the potassium compounds 3 and 4. The latter compounds show distinct field-induced slow magnetization relaxation. The energy barriers are 23.95 and 20.21 K for compounds 3 and 4, respectively.

A Racemic Polar Cobalt Phosphonate with Weak Ferromagnetism

Comfortably nemp: A novel polar compound [Co(2)(nemp)(2)(H(2)O)(2) ] incorporating racemic [1-(1-naphthyl)ethylamino]methylphosphonate (nemp(2-)) as a ligand is reported (see packing structure). This compound shows nonlinear optical properties at room temperature and weak ferromagnetism below 2 K.

Enhanced Magnetic Hardness in a Nanoscale Metal–Organic Hybrid Ferrimagnet

A new layered metal-organic hybrid compound, namely, [Co(3)(μ(3 -OH)(2)(BTP)(2)] (1; BTP=4-(3-bromothienyl)phosphonate), is reported. The inorganic layer can be viewed as a pseudo-Kagomé lattice composed of corner-sharing irregular triangles of Co(3) (μ(3)-OH), with the cavities filled with the PO(3) groups. The interlayer space is occupied by the 3-bromothienyl groups of BTP(2-). The bulk sample of compound 1 experiences a long-range ferromagnetic ordering below 30.5 K, with a coercivity (H(c)) of 5.04 kOe at 5 K. A systematic study on the size-dependent magnetic coercivity of 1 reveals that the coercivity of 1 increases with reduced particle size from the micrometer to the nanometer scale. When the particle size is about 50-200 nm, the coercivity reaches 24.2 kOe at 5 K. The results demonstrate that compound 1 can vary from a soft magnet to one of the hardest molecule-based magnets, simply by reducing the particle size to nanoscale region.

Ag(I)-mediated formation of pyrophosphonate coupled with C–C bond cleavage of acetonitrile

A general approach to obtain pyrophosphonates is achieved by reacting arylphosphonic acids with AgNO(3) in CH(3)CN under solvothermal conditions; the process is coupled with the C-C bond cleavage of acetonitrile and the formation of novel complexes [Ag(n)(RPO(2)(O)O(2)PR)(m)](CN); the mechanism of the process is proposed.

Lanthanide phosphonates with pseudo-D5h local symmetry exhibiting magnetic and luminescence bifunctional properties

Two lanthanide(III) phosphonates [Ln(notpH4)(H2O)]ClO4·3H2O [Ln = Dy(1), Ho(2)] in which the lanthanide ion has a pseudo-D5h symmetry have been reported. Both show layer structures where the neighbouring lanthanide atoms are connected by a pair of O–P–O bridges. Magnetic studies reveal that field-induced slow relaxation can be observed in both cases. Complex 1 is of particular interest because it shows not only field-tunable dual relaxation processes originating from the single ion anisotropy as well as the spin collective effect, but also simultaneous emissions from the metal ion, the ligand and the radiative energy transfer from the ligand to metal. The emission of DyIII can be correlated to the magnetic data.