Temperature dependence of the lanthanide-induced shifts, structure, and dynamics of adducts of quinuclidine and Ln(fod)3 chelates as studied by variable-temperature NMR shift and relaxation measurements

1982 ◽  
Vol 104 (6) ◽  
pp. 1632-1636 ◽  
Author(s):  
W. M. M. J. Bovee ◽  
J. H. Alberts ◽  
J. A. Peters ◽  
J. Smidt
Keyword(s):  
Temperature Dependence ◽  
Variable Temperature ◽  
Lanthanide Induced Shifts ◽  
Structure And Dynamics ◽  
Relaxation Measurements

Variable Temperature Nuclear Magnetic Resonance Studies of Some Five-Membered Ring Chelate Complexes

1975 ◽  
Vol 53 (7) ◽  
pp. 1038-1045 ◽  
Author(s):  
William R. Cullen ◽  
Laurance D. Hall ◽  
John E. H. Ward
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Temperature Dependence ◽  
Significant Variation ◽  
Conformational Equilibrium ◽  
Variable Temperature ◽  
Membered Ring ◽  
Coupling Constants ◽  
Chelate Complexes ◽  
Magnetic Resonance Studies

The temperature dependence of the n.m.r. spectra of nine ditertiary arsine chelate complexes of formula (CH3)2AsC(3)(3′)C(4) (4′)As(CH3)2M(CO)3X has been studied (M = Mo, Cr; X = CO; M = Mn; X = halogen; (3), (3′), (4), (4′) = H, F, Si(CH3)3, CN; but not all combinations ). Significant variation in coupling constants, indicating a shift in the conformer populations, was found only for the CHFCF2 bridged Mn(CO)3Cl complex, the CH2CF2 bridged Mn(CO)3Cl complex, and the CHFCHF bridged Mo(CO)4 complex. In the last case the 3JHH coupling constants were used to estimate ΔH ∼ 1 kcal/mol and ΔS ∼ 3 e.u for the conformational equilibrium.

TEMPERATURE-DEPENDENT MICROWAVE PERFORMANCE OF SB-HETEROSTRUCTURE BACKWARD DIODES FOR MILLIMETER-WAVE DETECTION

2007 ◽  
Vol 17 (01) ◽  
pp. 105-110
Author(s):  
N. SU ◽  
Z. ZHANG ◽  
P. FAY ◽  
H. P. MOYER ◽  
R. D. RAJAVEL ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Millimeter Wave ◽  
Variable Temperature ◽  
Device Performance ◽  
Material System ◽  
Temperature Dependent ◽  
Junction Resistance ◽  
Measured Voltage ◽  
Wave Detection ◽  
Self Consistent

The temperature dependence of heterostructure backward diodes based on the InAs/AlGaSb/GaSb material system for millimeter-wave detection has been investigated experimentally. Measured dc curvatures of 36 V-1 at 298 K and 74 V-1 at 4.2 K have been obtained. Variable-temperature on-wafer s-parameters to 110 GHz reveal that the junction capacitance of a typical 2×2 μ m 2 area device decreases from 18 fF at 298 K to 11 fF at 77 K, while the junction resistance decreases from 13.9 kΩ to 10.2 kΩ. Directly measured voltage sensitivities at 50 GHz of 3650 V/W and 7190 V/W were obtained at 298 K and 4.2 K, respectively, consistent with the expected value from measured dc curvature. A 1 dB compression point of 18.5 μW and 7.2 μW at 298 K and 77 K, respectively, was measured. A physical model based on self-consistent Poisson-Schrödinger equation solutions was obtained to explain the experimental observations, and suggests the ways to further improve the device performance.

scholarly journals The temperature dependence of C–H⋯F–C interactions in benzene : hexafluorobenzene

CrystEngComm ◽  
2018 ◽  
Vol 20 (42) ◽  
pp. 6677-6682 ◽  
Author(s):  
Jeremy K. Cockcroft ◽  
Alexander Rosu-Finsen ◽  
Andrew N. Fitch ◽  
Jeffrey H. Williams
Keyword(s):  
Solid State ◽  
Neutron Diffraction ◽  
Temperature Dependence ◽  
Variable Temperature ◽  
Intermolecular Forces ◽  
X Ray

Variable temperature X-ray and neutron diffraction and simple ideas of intermolecular forces permit a rationalization of the 4 phases observed for the solid-state adduct of benzene and hexafluorobenzene.

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