A First Comparison of Solid State and Solution Structure of a Complex between Lanthanum Nitrate and 1,9-Diaza-18-crown-6

2001 ◽  
Vol 3 (3) ◽  
pp. 325-327 ◽  
Author(s):  
Alla K. Shestakova ◽  
Vyacheslav A. Chertkov ◽  
Hans-Jörg Schneider ◽  
Konstantin A. Lysenko
2007 ◽  
Vol 2007 ◽  
pp. 1-4 ◽  
Author(s):  
Falk Liebner ◽  
Antje Potthast ◽  
Thomas Rosenau ◽  
Emmerich Haimer ◽  
Martin Wendland

Cellulose aerogels are intriguing new materials produced by supercritical drying of regenerated cellulose obtained by solvent exchange of solid Lyocell moldings. FromN-methylmorpholine-N-oxide solutions with cellulose contents between 1 and 12%, dimensionally stable cellulose bodies are produced, in which the solution structure of the cellulose is largely preserved and transferred into the solid state. The specific density and surface of the obtained aerogels range from 0.05 to 0.26 g/cm3and from 172 to 284m2/g, respectively, depending on the cellulose content of the Lyocell dopes and regeneration procedure. A reliable extraction and drying procedure using supercritical carbon dioxide, the advantageous use of NBnMO as stabilizer for the Lyocell dopes, and selected physical properties of the materials is communicated.


2009 ◽  
Vol 2009 (8) ◽  
pp. 1086-1095 ◽  
Author(s):  
Cristina Núñez ◽  
Marta Mato-Iglesias ◽  
Rufina Bastida ◽  
Alejandro Macías ◽  
Paulo Pérez-Lourido ◽  
...  

2013 ◽  
Vol 69 (12) ◽  
pp. 1437-1447 ◽  
Author(s):  
Madeleine Schultz ◽  
Philipp-Nikolaus Plessow ◽  
Frank Rominger ◽  
Laura Weigel

The complex [1,2-bis(di-tert-butylphosphanyl)ethane-κ2P,P′]diiodidonickel(II), [NiI2(C18H40P2] or (dtbpe-κ2P)NiI2, [dtbpe is 1,2-bis(di-tert-butylphosphanyl)ethane], is bright blue–green in the solid state and in solution, but, contrary to the structure predicted for a blue or green nickel(II) bis(phosphine) complex, it is found to be close to square planar in the solid state. The solution structure is deduced to be similar, because the optical spectra measured in solution and in the solid state contain similar absorptions. In solution at room temperature, no31P{1H} NMR resonance is observed, but the very small solid-state magnetic moment at temperatures down to 4 K indicates that the weak paramagnetism of this nickel(II) complex can be ascribed to temperature independent paramagnetism, and that the complex has no unpaired electrons. The red [1,2-bis(di-tert-butylphosphanyl)ethane-κ2P,P′]dichloridonickel(II), [NiCl2(C18H40P2] or (dtbpe-κ2P)NiCl2, is very close to square planar and very weakly paramagnetic in the solid state and in solution, while the maroon [1,2-bis(di-tert-butylphosphanyl)ethane-κ2P,P′]dibromidonickel(II), [NiBr2(C18H40P2] or (dtbpe-κ2P)NiBr2, is isostructural with the diiodide in the solid state, and displays paramagnetism intermediate between that of the dichloride and the diiodide in the solid state and in solution. Density functional calculations demonstrate that distortion from an ideal square plane for these complexes occurs on a flat potential energy surface. The calculations reproduce the observed structures and colours, and explain the trends observed for these and similar complexes. Although theoretical investigation identified magnetic-dipole-allowed excitations that are characteristic for temperature-independent paramagnetism (TIP), theory predicts the molecules to be diamagnetic.


1990 ◽  
Vol 29 (23) ◽  
pp. 4637-4640 ◽  
Author(s):  
Donald J. Darensbourg ◽  
Chi Shan Chao ◽  
Christopher Bischoff ◽  
Joseph H. Reibenspies

1987 ◽  
Vol 42 (11) ◽  
pp. 1419-1423 ◽  
Author(s):  
Erhard T. K. Haupt ◽  
Heindirk tom Dieck ◽  
Panayot R. Bontchev

The complete analysis of the 1H, 13C, 15N NMR spectra of iminopyrophthalone demonstrates that the solution structure of the molecule must be described as a protonated iminocompound. 13C-CP/MAS spectroscopy proves that the solid state structure of α-PPH and IPH are equivalent to the solution structure.


1993 ◽  
Vol 12 (11) ◽  
pp. 4376-4380 ◽  
Author(s):  
Jose M. Casas ◽  
Juan Fornies ◽  
Antonio Martin ◽  
Babil Menjon

1993 ◽  
Vol 115 (15) ◽  
pp. 6769-6776 ◽  
Author(s):  
Debbie C. Crans ◽  
Haojiang Chen ◽  
Oren P. Anderson ◽  
Mary M. Miller

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