Martin M. Kimani

Hydrothermal Synthesis and Spectroscopic Properties of a New Glaserite Material, K3RE(VO4)2 (RE = Sc, Y, Dy, Ho, Er, Yb, Lu, or Tm) with Potential Lasing and Optical Properties

A new series of materials of the glaserite family with the general formula K(3)RE(VO(4))(2)(RE = Sc, Y, Dy, Ho, Er, Tm, Yb, and Lu) have been hydrothermally synthesized using 10 M K(2)CO(3) at 560 °C and characterized by single crystal X-ray diffraction (XRD), powder XRD, differential thermal analysis/thermogravimetric analysis (DTA/TGA), energy-dispersion X-ray (EDX), Raman, infrared, and absorption spectroscopy. All the compounds crystallize in the trigonal P3̅m1 space group (No. 164), and their structures contain VO(4) tetrahedra, REO(6) octahedra, and two different K(1)O(10) and K(2)O(12) polyhedra. The spectroscopic properties of Nd(3+), Yb(3+), or Er(3+) doped K(3)RE(VO(4))(2) (RE = Y or Lu) are also reported, and the results obtained show that these compounds have promising potential as new laser host materials.

Hydrothermal synthesis and comparative coordination chemistry of new rare-earth V4+ compounds.

Several new hydrated rare earth vanadates and rare earth oxy-vanadates have been synthesized using hydrothermal techniques and characterized using single crystal and powder X-ray diffraction and infrared and UV-vis absorption spectroscopies. The hydrated rare earth vanadates adopt the space group P2(1)/m with general formula A(3)VO(5)(OH)(3) (A = Y (1), Dy (2), or La (3)) and contain anionic distorted square pyramidal [VO(5)](-6) units and AO(7) and AO(8) polyhedra. The oxy-vanadates with the general formula A(2)O(VO(4)) (A = Y (4), Dy (5; 6), or Yb (7)) form two polymorphs in either P2(1)/c or C2/c space groups and contain anionic tetrahedral [VO(4)](-4) units and nonvanadium bonded O(2-) anions in distorted [OA(4)] tetrahedra. In all cases, the vanadium ion is in the tetravalent oxidation state, and its original source was the trace V(4+) impurities in YVO(4). The observed vanadyl and equatorial vanadium-oxygen bond lengths about the square pyramid in compounds 1-3 and the tetrahedral vanadium coordination found in compounds 4-7 are unusual for V(4+). The electronic and vibrational spectra are also reported and correlated with the appropriate coordination environment.

The diselanylbis(1,3-dimethyl-1H-imidazol-3-ium) dication stabilized by the polymeric catena-pentachloridotricuprate(I) anion

In the title compound, catena-poly[diselanylbis(1,3-dimethyl-1H-imidazol-3-ium) [μ(3)-chlorido-tetra-μ(2)-chlorido-tricuprate(I)]], {(C(10)H(16)N(4)Se(2))[Cu(3)Cl(5)]}(n), the diselenide dication is stabilized by catena-[Cu(3)Cl(5)](2-) anions which associate through strong Cu-Cl bonds [average length = 2.3525 (13) Å] to form polymeric chains. The polymeric [Cu(3)Cl(5)](2-) anion contains crystallographically imposed twofold rotation symmetry, with distorted trigonal-planar and tetrahedral geometries around the two symmetry-independent Cu atoms. Likewise, the Se-Se bond of the cation is centered on a twofold rotation axis.

Dinuclear copper(i) complexes with N-heterocyclic thione and selone ligands

The synthesis, characterization, and structures of a series of homoleptic and heteroleptic copper(I) complexes supported by N-heterocyclic chalcogenone ligands is reported herein. The quasi-reversible Cu(II/I) reduction potentials of these copper complexes with monodentate (dmit or dmise) and/or bidentate (Bmm(Me), Bsem(Me), Bme(Me), Bsee(Me)) chalcogenone ligands are highly dependent upon the nature and number of the donor groups and can be tuned over a 470 mV range (-369 to 102 mV). Copper-selone complexes have more negative Cu(II/I) reduction potentials relative to their thione analogs by an average of 137 mV, and increasing the number of methylene units linking the heterocyclic rings in the bidentate ligands results in more negative reduction potentials for their copper complexes. This ability to tune the copper reduction potentials over a wide range has potential applications in synthetic and industrial catalysis as well as the understanding of important biological processes such as electron transfer in blue copper proteins and respiration.