Charge ordering in non-dimerized BEDT-TTF based organic conductors: 13C-NMR experiments

2002 ◽  
Vol 12 (9) ◽  
pp. 201-204
Author(s):  
T. Takahashi ◽  
R. Chiba ◽  
Y. Takano ◽  
Y. Kubo ◽  
K. Hiraki ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Charge Order ◽  
Organic Conductors ◽  
Charge Ordering ◽  
Metallic State ◽  
Two Dimensional ◽  
Charge Disproportionation ◽  
Nmr Techniques ◽  
Mi Transition ◽  
C Nmr

Experimental evidences of the charge ordering with the use of 13C-NMR techniques in various organic conductors are reviewed. In the insulating states of two-dimensional BEDT-TTF salts, a-I, and 8-RbZn(SCN)4, the formation of charge stripes perpendicular to molecular stacks are confiied. Charge disproportionation is estimated as 0.8:0.2 in the latter and more in the former. It is also observed that charge disproportionation already develops well above the MI transition temperature while no long-range charge order is stabilized. This seems to require a serious reconsideration of the transport properties in the `metallic' state.

ELECTRON MAGNETIC RESONANCE FERMI SURFACE IMAGING: APPLICATIONS TO ORGANIC CONDUCTORS AND Sr2RuO4

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3109-3112
Author(s):  
S. HILL ◽  
A. KOVALEV ◽  
M. M. MOLA ◽  
C. PALASSIS ◽  
Z. Q. MAO ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Cyclotron Resonance ◽  
Charge Density Wave ◽  
Density Wave ◽  
Organic Conductors ◽  
Metallic State ◽  
Surface Imaging ◽  
Two Dimensional ◽  
Fermi Surfaces ◽  
Fermi Surface Nesting

We report detailed angle dependent studies of the metallic state microwave (40 to 200 GHz) magneto-conductivity of single crystal samples of the α- (BEDT-TTF) 2 KHg(SCN) 4 organic charge density wave conductor, and the perovskite superconductor Sr 2 RuO 4. We observe series' of resonant absorptions which we attribute to periodic orbit resonances - a phenomenon closely related to cyclotron resonance. By performing measurements on several samples, and in different electromagnetic field configurations, we are able to couple to different orbital modes (+ harmonics), which derive from deformations (warpings) of the quasi-one and quasi-two-dimensional Fermi surfaces of these compounds. These studies provide vital information concerning interlayer dispersion which, in turn, affects the Fermi surface nesting characteristics which are believed to play a crucial role in the low temperature physics of these exotic materials.

Superconducting and charge ordering phases of two-dimensional organic conductors

2006 ◽  
Vol 142 (3-4) ◽  
pp. 535-538 ◽  
Author(s):  
R. Kondo ◽  
M. Higa ◽  
S. Kagoshima
Keyword(s):  
Organic Conductors ◽  
Charge Ordering ◽  
Two Dimensional

Isolation and Structure Determination of Three New Sesquiterpenoids from Achillea millefolium

2012 ◽  
Vol 67 (5) ◽  
pp. 421-425 ◽  
Author(s):  
Umar Farooq ◽  
Afsar Khan ◽  
Saleha Suleman Khan ◽  
Shazia Iqbal ◽  
Rizwana Sarwar ◽  
...  
Keyword(s):  
Sesquiterpene Lactone ◽  
2D Nmr ◽  
Achillea Millefolium ◽  
Two Dimensional ◽  
H Nmr ◽  
Whole Plant ◽  
Phytochemical Investigation ◽  
Nmr Techniques ◽  
C Nmr

Phytochemical investigation of the whole plant of Achillea millefolium led to the isolation of three new sesquiterpenes which were trivially named as sesquiterpene lactone-esters A and B (1 and 2), and sesquiterpene lactone-diol (3). The structures of these compounds were determined with the help of one- and two-dimensional (1D and 2D) NMR techniques including 1H NMR, 13C NMR, HMQC, HMBC, COSY, and NOESY experiments.

Two Dimensional 1H–1H and 13C–1H-Correlation NMR: The Analysis of η3-Allylnickel Complexes

1982 ◽  
Vol 37 (8) ◽  
pp. 1054-1057 ◽  
Author(s):  
Reinhard Benn
Keyword(s):  
Nmr Spectra ◽  
Nickel Complexes ◽  
Routine Analysis ◽  
Two Dimensional ◽  
Nmr Techniques ◽  
C Nmr

Abstract The 1H and 13C NMR spectra of various alkylsubstituted η3-allyl-η5-cyclopentadienyl-nickel complexes were analysed with the help of two dimensional correlation (1H-1H and 1H-13C) NMR. The use of two dimensional NMR techniques for the routine analysis of complicated NMR spectra is demonstrated.

scholarly journals Two New Sesquiterpene Lactone-esters from Achillea vermicularis

2008 ◽  
Vol 3 (11) ◽  
pp. 1934578X0800301
Author(s):  
Umar Farooq ◽  
Afsar Khan ◽  
Viqar Uddin Ahmad ◽  
Azhar-ul-Haq ◽  
Robina Farooq ◽  
...  
Keyword(s):  
Sesquiterpene Lactone ◽  
2D Nmr ◽  
Two Dimensional ◽  
H Nmr ◽  
Whole Plant ◽  
Phytochemical Investigation ◽  
Nmr Techniques ◽  
C Nmr

Phytochemical investigation of the whole plant of Achillea vermicularis led to the isolation of two new sesquiterpene lactone-esters, vermicularon A and B (1–2). The structures of these compounds were determined primarily with the help of one- and two-dimensional (1D and 2D) NMR techniques, including 1H NMR, 13C NMR, HMQC, and HMBC experiments.

Sign in / Sign up

Export Citation Format

Share Document