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Neutron Scattering Investigations of Thermoelectric Materials
Published in D. M. Rowe, Materials, Preparation, and Characterization in Thermoelectrics, 2017
Here, 〈uxx2〉 is the displacement along xx, which is one of the main axis in the thermal ellipsoid and θE,xx is the Einstein temperature along the same direction. The guest atom mass is given by m and d2 represents temperature-independent disorder. A low Einstein temperature corresponds to a guest atom phonon mode at low energy, which through hybridization with the acoustic phonon modes can cause avoided crossing. An avoided crossing introduces flat phonon modes which lowers the group velocity, and in turn reduces the thermal conductivity.7 A schematic illustration of the Debye and Einstein modes in a phonon dispersion relation is shown in Figure 23.6.
N − H bond dissociation free energy of a terminal iron phosphinimine
Published in Journal of Coordination Chemistry, 2022
Heui Beom Lee, R. David Britt, Jonathan Rittle
Suitable crystals were mounted on a nylon loop using Paratone oil, then placed on a diffractometer under a nitrogen stream. X-ray intensity data were collected on a ROD, Synergy Custom DW system, Pilatus 200 K detector employing Mo-Kα or Cu-Kα radiation at a temperature of 100 K. All diffractometer manipulations, including data collection, integration and scaling, were carried out using CrysAlisPro 1.171.40.61a (Rigaku OD, 2019) software. Using Olex2, the structures were solved by intrinsic phasing using ShelXT [23] and refined to convergence by full-matrix least squares minimization using ShelXL [23]. All non-solvent non-hydrogen atoms were refined using anisotropic displacement parameters. Hydrogen atoms were placed in idealized positions and refined using a riding model. Graphical representations of structures with 50% probability thermal ellipsoids were generated using Diamond visualization software.
Synthesis, spectroscopic characterization, X-ray crystal structure, antimicrobial, DNA-binding, alkaline phosphatase and insulin-mimetic studies of oxidovanadium(IV) complexes of azomethine precursors
Published in Journal of Coordination Chemistry, 2020
Khurram Shahzad Munawar, Saqib Ali, Muhammad Nawaz Tahir, Nasir Khalid, Qamar Abbas, Irfan Zia Qureshi, Shabbir Hussain, Muhammad Ashfaq
Elemental analysis of the synthesized compounds was carried out on an Elemental Vario EL elemental analyzer. FT-IR spectra in the range of 4000–400 cm−1 were obtained on a Thermo Nicolet-6700 FT-IR spectrophotometer. Multinuclear (1H and 13C) NMR spectra were recorded on a Bruker-400 MHz FT-NMR spectrometer using DMSO-d6 as a solvent [δ1H (DMSO) = 2.5 ppm and δ13C (DMSO) = 39 ppm]. Chemical shifts are given in ppm and coupling constants (J) values are reported in Hz. The multiplicity of 1H NMR signals (s = singlet, d = doublet, dd = doublets of doublet, t = triplet, dt = doublets of triplet and m = multiplet) are mentioned with chemical shifts. The absorption spectra were measured on a Shimadzu 1800 UV–visible spectrophotometer. The melting points were determined in capillary tubes using an electrothermal melting point apparatus (Gallenkamp). Magnetic moment was determined by using Sherwood magnetic susceptibility balance at ambient temperature (25 ± 2 °C), using Hg[Co(SCN)4] as calibrant. Thermogravimetric analysis was performed by Universal V4.3A TA Instruments. The XRD data of the titled compounds were collected using the diffractometer Bruker KAPPA Apex-II having monochromator made of graphite providing finely focused Kα X-rays, a CCD detector for recording of diffraction peaks. Apex-II (Bruker 2009), SHELXS97 and SHELXS2014/6 software were used for data collection, solution of structure and structure refinement, respectively. Thermal ellipsoid diagrams were drawn by ORTEP-3 software [28]. Packing of molecules for the compounds were shown by PLATON software whereas Mercury 4.0 was used for graphical representation of π–π stacking interaction.