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Filters: Date: "2002" Department: "Chemistry" Collection: "ir_uspace"
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CreatorTitleDescriptionSubjectDate
1 Miller, Joel Steven1H NMR investigation of the magnetic spin configuration in the molecule-based ferrimagnet [MnTFPP][TCNE]1H NMR line-shape measurements have been performed in the linear chain molecule-based ferrimagnet [MnTFPP][TCNE].xPhMe (TFPP=tetrakis(4-fluorophenyl)porphinato; TCNE=tetracyanoethylene) as a function of temperature. Hyperfine shifts of opposite sign were observed indicating the presence of two oppo...Magnetization; Magnets; Paramagnetic2002
2 Miller, Joel StevenCharge transfer complexes of 2,4,6-tricyano-s-triazine with tetrathiafulvalene (TTF) and N,N,N' ,N'-tetramethyl-p-phenylenediamine (TMPD)Reaction of 2,4,6-tricyano-s-triazine (TCT) with tetrathiafulvalene (TTF) and N,N,N',N'-tetramethylp-phenylenediamine (TMPD) leads to 1 : 1 charge transfer complexes. The crystal structures of the TTF[TCT], as well as the decomposition product due to hydrolysis of the [TMPD][TCT], i.e. HTMPD]+[2,4-d...Electron; Solution; Hydrolysis2002
3 Armentrout, Peter B.Guided ion beam studies of the reaction of Nin+ (n=2-16) with D2: nickel cluster-deuteride bond energiesThe kinetic-energy dependences of the reactions of Nin+ (n=2-16) with D2 are studied in a guided ion beam tandem mass spectrometer. The products observed are NinD+ for all clusters and NinD2 + for n=5-16. Reactions for formation of NinD+ are observed to exhibit thresholds, whereas cross sections for...Metal clusters; Nickel ions; Bond energies; Deuterides; Collision-induced dissociation; Endothermic reactions2002
4 Armentrout, Peter B.Guided ion beam studies of the reactions of Vn+ (n = 2-13) with D2: cluster-deuteride bond energies as a chemical probe of cluster electronic structureThe kinetic energy dependencies of the reactions of Vn+ (n=2 - 13) with D2 are studied in a guided ion beam tandem mass spectrometer. Products observed are VnD1 for all clusters and VnD2 + for n=4 - 13. All reactions are observed to exhibit thresholds, except for formation of VnD2 + for n =4,5,7,9,1...Metal clusters; Vanadium ions; Bond energies; Endothermic reactions; Collision-induced dissociation; Transition metal ions; Deuterides2002
5 Miller, Joel StevenInnovation in crystal engineeringThe first CrystEngComm discussion meeting on crystal engineering has demonstrated that the field has reached maturity in some areas (for example: design strategies, characterization of solid compounds, topological analysis of weak and strong non-covalent interactions), while the quest for novel pro...Research; Design; Molecular2002
6 Miller, Joel StevenIsolation of two salts from the reduction of TCNE with [(n-C3H7)4N]I. A further example of long 2.87 Ã pi-C-C bonding in pi-[TCNE]22-Reduction of tetracyanoethylene, TCNE, with tetrakis(n-propyl)ammonium iodide, [Pr4N]I, results in a new example of long pi*-CC bonded pi-[TCNE]22- dimers with a 2.870(4) A(°) intradimer CC bond, which is structurally and spectroscopically characterized. This reaction also results in isolation of ...Synthesis; Intradimer; Crystals2002
7 Miller, Joel StevenNovel coordination of dicyanamide, [N(CN)2]-: preferential binding of the amide nitrogenCoII[N(CN)2]2(H2BiIm)2, 1, and {CoII[N(CN)2](H- 2BiIm)2}Cl, 2 (H2BiIm = 2,2'-biimidazole) have been structurally, spectroscopically, and magnetically characterized with both containing dicyanamides bound in unprecedented manners; namely, solely via the amide nitrogen for 1, and via an imide N form...Magnetic; Dicyanamide; Electron2002
8 Miller, Joel StevenOn the existence of long C-C bonds between pairs of anions which repel: when and why? A test case on the [TCNE]22- dimers found in ionic crystals*Many of the Cm[TCNE]n (C = cation) salts have intradimer C-C interactions in the range of 2.9 to 3.5 A(°) and show the electronic fingerprints associated with C-C bond formation (IR and UV spectra, magnetic properties, structural changes), despite the fact that two [TCNE].- anions should repel each...Electron; Spectroscopic; Salts2002
9 Miller, Joel Steven; Epstein, Arthur J.Optical control of magnetic order in molecule-based magnet Mn(TCNE)x.y(CH2Cl2)Studies of photoinduced magnetization and photoinduced absorption in molecule-based magnet Mn(TCNE)x•y(CH2Cl2) (x=2, y-0.8, TCNE=tetracyanoethylene) are reported. Optical excitation in the blue region of spectrum leads to increased magnetization, accompanied by changes in the electronic spectrum...Spectrum; Absorption; Illumination2002
10 Morse, Michael DavidOptical spectroscopy of tungsten carbide (WC)Resonant two-photon ionization spectroscopy has been used to study the diatomic transition-metal carbide, WC. A low-resolution scan revealed a five-member vibrational progression beginning with the 0-0 band at 17 585 cm-1. Analysis of this progression yielded a vibrational frequency of ?'e8(184W12C)...2002
11 Miller, Joel Steven; Epstein, Arthur J.Photoinduced magnetization in the organic-based magnet Mn(TCNE)x.y(CH2Cl2)Photoinduced magnetization in a magnet based on organic species is reported for the first time. Upon optical excitation in the blue region of spectrum, Mn (tetracyanoethylene)x .y(CH2Cl2) (x=2,y-0.8) exhibits increased magnetic susceptibility at temperatures as high as 75 K, accompanied with photo-i...Absorption; Magnetic; Infrared2002
12 Armentrout, Peter B.Reactions of Pt+ with H2, D2, and HD: effect of lanthanide contraction on reactivity and thermochemistryA guided ion beam tandem mass spectrometer is used to examine the kinetic energy dependence of reactions of the third-row transition metal cation, Pt1, with molecular hydrogen and its isotopologs. A flow tube ion source produces Pt1 ions in its electronic ground state term and primarily in the lowes...Metal clusters; Platinum ions; Lanthanide contraction; Bond energies; Endothermic reactions; Transition metal ions; Dihydrogen2002
13 Armentrout, Peter B.Reactions of Ta+ and W+ with H2, D2, and HD: effect of lanthanide contraction and spin-orbit interactions on reactivity and thermochemistryA guided ion beam tandem mass spectrometer is used to examine the kinetic energy dependence of reactions of the third-row transition metal cations, Ta1, and W1, with molecular hydrogen and its isotopologs. A flow tube ion source produces Ta1 and W1 ions in their electronic ground state term and p...Metal clusters; Tantalum ions; Tungsten ions; Lanthanide contraction; Bond energies; Endothermic reactions; Transition metal ions; Dihydrogen2002
14 Armentrout, Peter B.Reactions of Ta+, W+, and Pt+ with H2, D2, and HD: effect of lanthanide contraction and spin-orbit interactions on reactivity and thermochemistryThere have been extensive experimental studies of the reactions of atomic first-row and second-row transition metal cations with dihydrogen and its isotopic analogues in our group. For third-row transition metal cations, however, only La+ and Lu+ systems have been studied experimentally although t...Lanthanide contraction; Spin-Orbit interactions; Reactivity2002
15 Morse, Michael DavidResonant two-photon ionization spectroscopy of NiCA spectroscopic investigation of jet-cooled diatomic NiC has revealed a complex pattern of vibronic levels in the wave number range from 21 700 to 27 000 cm-1. Of the more than 50 vibronic bands observed, 31 have been rotationally resolved and analyzed. All are ?'=0+??"=0+ transitions, consistent wi...2002
16 Morse, Michael DavidRotationally resolved spectra of Pt?High-resolution laser-induced fluorescence spectroscopy has been used to investigate the 18 163 cm21 band of Pt2 in a supersonically cooled molecular beam. Rotational constants of the ground and excited states were extracted from the rotationally resolved spectrum and determined to be B0'=0.031 754(...2002
17 Wight, Charles AlbertThermal activation of the high explosive NTO: sublimation, decomposition, and autocatalysisThermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) show that the heating of 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO) leads to competitive sublimation and condensed-phase exothermic decomposition. Model-free isoconversional analysis has determined activation energies...NTO; Thermal activation; Differential scanning calorimetry; Exothermic decomposition; Competitive sublimation2002
18 Wight, Charles AlbertThermal decomposition of a melt-castable high explosive: isoconversional analysis of TNAZThe thermal decomposition kinetics of the high explosive 1,3,3-trinitroazetidine (TNAZ) have been measured by nonisothermal differential scanning calorimetry (DSC). Samples of TNAZ in open pans and pierced pans undergo mainly melting (?Hfus = 27 ± 3 kJ mol-1) and vaporization (?Hvap = 74 ± 10 kJ m...Thermal decomposition; Melt-castable high explosive; TNAZ; Nonisothermal differential scanning calorimetry; Exothermic decomposition2002
19 Armentrout, Peter B.Thermochemistry of small cationic iron-sulfur clustersThe kinetic energy dependences of the reactions of Fen 1 with COS (n=2-6) and CS2 (n=2-5) are studied in a guided-ion beam tandem mass-spectrometer. The main products arise from sulfur transfer and subsequent losses of Fe atoms. In the case of CS2 , this reactant also formally replaces one Fe atom ...Iron-sulfur clusters; Endothermic reactions; Bond energy2002
20 Miller, Joel Steven; Epstein, Arthur J.Viscous behavior in a quasi-1D fractal cluster glassThe spin glass transition of a quasi-1D organic-based magnet ([MnTPP][TCNE]) is explored using both ac and dc measurements. A scaling analysis of the ac susceptibility shows a spin glass transition near 4 K, with a viscous decay of the thermoremanent magnetization recorded above 4 K.We propose an ex...Transition; Magnet; Magnetization2002
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