UNLV Community Concert Band

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Comparison of mol­ecular structures of cis-bis­[8-(di­methyl­phosphan­yl)quinoline]­nickel(II) and -platinum(II) complex cations

The crystal structures of the complexes (SP-4-2)-cis-bis[8-(dimethylphosphanyl)quinoline-κ2 N,P]nickel(II) bis(perchlorate) nitromethane monosolvate, [Ni(C11H12NP)2](ClO4)2·CH3NO2 (1), and (SP-4-2)-cis-bis[8-(dimethylphosphanyl)quinoline-κ2 N,P]platinum(II) bis(tetrafluoroborate) acetonitrile monosolvate, [Pt(C11H12NP)2](BF4)2·C2H3N (2), are reported. In both complex cations, two phosphanylquinolines act as bidentate P,N-donating chelate ligands and form the mutually cis configuration in the square-planar coordination geometry. The strong trans influence of the dimethylphosphanyl donor group is confirmed by the Ni—N bond lengths in 1, 1.970 (2) and 1.982 (2) Å and, the Pt—N bond lengths of 2, 2.123 (4) and 2.132 (4) Å, which are relatively long as compared to those in the analogous 8-(diphenylphosphanyl)quinoline complexes. Mutually cis-positioned quinoline donor groups would give a severe steric hindrance between their ortho-H atoms. In order to reduce such a steric congestion, the NiII complex in 1 shows a tetrahedral distortion of the coordination geometry, as parameterized by τ4 = 0.199 (1)°, while the PtII complex in 2 exhibits a typical square-planar coordination geometry [τ4 = 0.014 (1)°] with a large bending deformation of the ideally planar Me2Pqn chelate planes. In the crystal structure of 2, three F atoms of one of the BF4 − anions are disordered over two sets of positions with refined occupancies of 0.573 (10) and 0.427 (10).</jats:p

Bis[μ-2-(aminosulfanyl)pyridine(1−)]bis­[(η5-penta­methyl­cyclo­penta­dien­yl)iridium(III)] diiodide

In the title dinuclear iridium(III) complex, [Ir2(C10H15)2(C5H5N2S)2]I2, the iridium(III) atoms are bridged by 2-(aminosulfanyl)pyridine(1−) [(2-py)SNH] ligands in a μ-(2-py)SNH-κ2 N(py),N(NH):κN(NH) mode. The dinuclear complex cation lies on a crystallographic inversion center, resulting in a planar Ir2N2 ring with an Ir—N(py) bond length of 2.085 (9) Å and bridging Ir—N(NH) bonds of 2.110 (9) and 2.113 (9) Å. The two (2-py)S units have mutually anti configurations with respect to the Ir2N2 rin

Presentation by the University of Nevada, Las Vegas: College of Fine Arts

Program listing performers and works performe

Presentation by the University of Nevada, Las Vegas: College of Fine Arts

Program listing performers and works performe

Leakage-free electrolytes with different conductivity for non-volatile memory device utilizing insulator/metal ferromagnet transition of SrCoOx

The electrochemical switching of SrCoOx-based non-volatile memory with thin-film-transistor structure was examined by using liquid-leakage-free electrolytes with different conductivity (s) as the gate insulator. We first examined leakage-free water, which is incorporated in the amorphous (a-) 12CaO 7Al2O3 film with nanoporous structure (CAN), but the electrochemical oxidation/reduction of SrCoOx layer required the application of high gate voltage (Vg) up to 20 V for a very long retention-time (t) 40 minutes, primarily due to the low s (2.0 x 10-8 S cm-1 at RT) of leakage-free water.We then controlled the s of leakage-free electrolyte, infiltrated in the a-NaxTaO3 film with nanopillar array structure, from 8.0 x 10-8 S cm-1 to 2.5 x 10-6 S cm-1 at RT by changing the x = 0.01-1.0. As the result, the t, required for the metallization of SrCoOx layer under small Vg = -3 V, becomes two orders of magnitude shorter with increase of the s of the a-NaxTaO3 leakage-free electrolyte. These results indicate that the ion migration in the leakage-free electrolyte is the rate-determining step for the electrochemical switching, compared to the other electrochemical process, and the high s of the leakage-free electrolyte is the key factor for the development of the non-volatile SrCoOx-based electro-magnetic phase switching device

Syntheses and crystal structures of neodymium(III) and europium(III) complexes bearing dimethyl-, pyrrolidine-, or S-prolinol- dithiocarbamato ligands and their natural and magnetic circular dichroism spectra

A series of Nd-III and Eu-III complexes containing achiral or chiral dithiocarbamato (dtc) ligands, [Ln(Xdtc)(3)(NN)] {Ln = Nd or Eu; X = dimethyl- (Me-2), pyrrolidine- (pyr), or (S)-prolinol- (S-proOH); NN = 1,10-phenanthroline (phen) or 2,2'-bipyridine (bpy)}, were prepared and their crystal structures and spectroscopic properties, in particular the natural circular dichroism (CD) and magnetic circular dichroism (MCD), were investigated. The crystal structures of the complexes analyzed by the X-ray diffraction method showed an 8-coordinate geometry around the Ln III center with comparable structural parameters to one another and to the related complexes reported previously. These complexes exhibited similar spectral patterns in their absorption, natural CD and MCD spectra in solution. Weak but characteristic sharp f-f transition bands were observed in the absorption and MCD spectra, but no CD signals associated with these transitions were observed even in the S-proOHdtc complexes. The MCD spectral pattern of the Eu-III complexes revealed a local C-2v symmetry around the Ln(III) center in solution, in contrast to the aqua and the analogous beta-diketonato Eu-III complexes

Homodinuclear lanthanoid(III) dithiocarbamato complexes bridged by 2,2′-bipyrimidine: Syntheses, structures and spectroscopic properties

Four new homodinuclear lanthanoid(III) dithiocarbamato (RR'dtc(-)) complexes bridged by 2,2'-bipyrimidine (bpm) of the form [{Ln(RR'dtc)(3)}(2)(mu-bpm)] {Ln = Nd or Eu; RR' = dimethyl- (Me-2) or pyrrolidine(pyr)} were prepared and their crystal structures and spectroscopic properties were characterized. The crystallographic studies revealed that all of the complexes possess a similar structural motif with an 8:8-coordination geometry, in which the bpm ligand bridges two Ln(III) centers in the kappa N-2(1,1') : kappa N-2(3,3') mode and three RR'dtc(-) ligands coordinate to each Ln(III) center. The complexes exhibit weak but relatively sharp f-f transition bands in the absorption and magnetic circular dichroism (MCD) spectra recorded in the visible region. The MCD spectral studies demonstrated the magneto-optical behavior of the complexes. The spectral features of the dithiocarbamato complexes were distinctly different from those of their beta-diketonato analogues, suggesting the coordination environment around the Ln(III) center influences the electronic structure and spectroscopic symmetry of the complexes in solution