A novel differential scanning calorimetric method to study the complexation of β-cyclodextrin with steroid in solid state

1995 ◽  
Vol 45 (3) ◽  
pp. 573-576 ◽  
Author(s):  
K. Sreenivasan
1985 ◽  
Vol 38 (2) ◽  
pp. 261 ◽  
Author(s):  
PF Barron ◽  
JC Dyason ◽  
LM Engelhardt ◽  
PC Healy ◽  
AH White

The compounds, [(PPh3)4Cu] ClO4, (I), [(CH3CN)( PPh3)2 Cu] ClO4, (2), and [(CH3CN)2(PPh3)2Cu]-ClO4, (3) ( PPh3 = triphenylphosphine ), have been characterized by solid-state 31P n.m.r . spectroscopy and crystal structure analysis. Crystals of (2) are orthorhombic, Pcab , a 24.506(9), b 22.49(1), c 17.905(8) Ǻ, Z = 8; R was 0.089 for 2178 independent 'observed' reflections. Crystals of (3) are monoclinic, P21/n, a 15.506(6), b 26.98(1), c 9.220(3) Ǻ, β 94.70(3)°, Z = 4; R was 0.070 for 2622 independent reflections. In both cations, the copper(:) atom is four-coordinate by the phosphine and acetonitrile ligands . In (2), Cu-P are 2.321(5)-2.338(5) Ǻ, with Cu-N, 2.11(1) Ǻ; N-Cu-P lie between 100.1(3) and 106.0(3)°, while P-Cu-P range from 113.0(2) to 119.3(2)°. In (3), Cu-P are 2.257(3), 2.278(3) and Cu-N, 2.068(8) and 2.020(8) Ǻ; with P-Cu-P, 127.6(1), N-Cu-N, 99.2(3), and P-Cu-N, 101.7(2)-109.9(3)°. Solid state 31P n.m.r . spectra of (1), (2) and (3) show one, three and two sets of overlapping quartets respectively. The average chemical shift data for each quartet with respect to 85% phosphoric acid is: (1)-5.0ppm; (2)2.6, 1.2, -0.6 ppm ; (3) 4.0,-3.0 ppm [cf. free PPh3 in the solid state, -9.9 ppm ]. The magnitude, Δvi, and asymmetry, Avvij, of the splitting between the peaks of each quartet is consistent with a distorted tetrahedral environment for the three compounds. Infrared spectroscopic, differential scanning calorimetric, solid state 31P n.m.r . and powder XRD measurements show that heating of (2) and (3) leads to the desolvated complexes, [(PPh3)3CuClO4], (4), and [(PPh3)2CuClO4], (5), in which the perchlorate anions function as monodentate and bidentate ligands respectively.


2012 ◽  
Vol 67 (7) ◽  
pp. 667-672 ◽  
Author(s):  
Vittorio Berbenni ◽  
Chiara Milanese ◽  
Giovanna Bruni ◽  
Alessandro Girella ◽  
Amedeo Marini

The synthesis of barium metastannate, BaSnO3, by heating mixtures of metal oxalates, either physically mixed or subjected to a phase of mechanical activation, up to temperatures in the range 750- 1200 °C has been studied. Simultaneous thermogravimetric-differential scanning calorimetric (TGDSC) analyses and powder X-ray diffractometry have been applied to check the advancement of the reactions. BaSnO3, though slightly contaminated by BaCO3, can be obtained by heating the activated mixture up to T ≥ 1000 °C while heating a sample of a physical mixture at temperature as high as 1200 °C resulted in a mixture of BaSnO3, SnO2 and Ba2SnO4. The heat capacities of BaSnO3 samples prepared at temperatures between 1000 and 1200 °C have been measured by modulated temperature differential scanning calorimetry (MTDSC) in the temperature range 50-400 °C.


2010 ◽  
Vol 505 (1) ◽  
pp. 309-314 ◽  
Author(s):  
Ram Avtar Jat ◽  
S.C. Parida ◽  
K. Krishnan ◽  
N.S. Anand ◽  
S.G. Sawant ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Samiran Upadhyaya ◽  
Rajumani Sarma ◽  
Abdul Barik ◽  
Neelotpal Sen Sarma

Herein, we have reported the synthesis, characterization, and ionic conductivity analysis of fluorescent poly(1-vinyl-2-pyrrolidone-co-acrylonitrile) and its salts with 10% HCl and HNO3 in solid state. The synthesized polymers and their polysalts were characterized using Fourier-transformed infrared spectroscopy, UV-visible, Cyclic Voltammetry, Thermogravimetric analysis, Differential Scanning Calorimetric, X-ray diffraction, and spectrofluorometric techniques. The AC conductivities were measured in the frequency ranging from 42 Hz to 1 MHz and temperature from 30°C to 70°C in solid state. Ionic conductivities of the salts of the copolymer with hydrochloric acid and nitric acid were found to be 2.145×10−5 and 2.349×10−5 S cm −1, respectively, which are nearly 1000 times more than that of poly(1-vinyl-2-pyrrolidone-co-acrylonitrile). The activation energies for the copolymer and the polyelectrolytes were found to be 0.454, 0.6288, and 0.659 eV, respectively. The transport number of the copolymers was found to be 0.0278, and that of the polysalts was found to be 0.7596 and 0.7424, respectively. The copolymer showed distinct fluorescent when irradiated with UV light and can be used as acid vapor sensor in solid state.


2015 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
Antonio Sanchez-Fernandez ◽  
Laura Pena-Paras ◽  
Elisa M. Mendoza ◽  
Alejandra Leyva ◽  
Luis A. Bautista ◽  
...  

Polymers of organoalkoxysilanes (or polyalkoxysilanes) were synthesized through sol-gel process using different organosilanes: Tetraethylorthosilicate (TEOS), (3-Glycidyloxypropyl) trimethoxysilane (GPTMS), Trimethoxy(propyl)silane (TMPS), and/or Triethoxy(octyl)silane (EOS). Different carboxylic acids (acetic, formic, and citric) were used to prepare polyalkoxysilanes, with citric acid acting as a reactant rather than a catalyst for the sol-gel reaction. Silica-chitosan hybrid materials were synthesized reacting polyalkoxysilanes and chitosan, one of the most important and most studied natural polymers, through sol-gel process. The synthesized materials were characterized using Fourier transform infrared spectroscopy (FT-IR), thermogravimetrical analysis (TGA), differential Scanning Calorimetric (DSC) and solid-state Carbon-13 Nuclear Magnetic Resonance (solid-state   13C-NMR) spectroscopy, obtaining information on the structural properties of each modified materials. The results obtained by NMR indicate that the oxirane group of GPTMS remains in all reaction products to form different polyalkoxysilanes.


Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.


Sign in / Sign up

Export Citation Format

Share Document