Multinuclear NMR Studies of Ligand-Exchange Reactions on Analogous Technetium(V) and Rhenium(V) Complexes. Relevance to nuclear medicine

1992 ◽  
Vol 75 (1) ◽  
pp. 210-217 ◽  
Author(s):  
Lothar Helm ◽  
Karen Deutsch ◽  
Edward A. Deutsch ◽  
Andr� E. Merbach
Keyword(s):  
Nuclear Medicine ◽  
Ligand Exchange ◽  
Exchange Reactions ◽  
Nmr Studies ◽  
Multinuclear Nmr

scholarly journals Variable-pressure dynamic NMR studies: effects of paramagnetic metal ions on NMR parameters in nonexchanging systems

1994 ◽  
Vol 72 (10) ◽  
pp. 2188-2192 ◽  
Author(s):  
Hideo D. Takagi ◽  
Kayoko Matsuda ◽  
Sen-Ichi Aizawa ◽  
Shigenobu Funahashi ◽  
Stephen D. Kinrade ◽  
...  
Keyword(s):  
Ligand Exchange ◽  
High Pressures ◽  
Activation Volume ◽  
Chemical Exchange ◽  
Chemical Shifts ◽  
Variable Pressure ◽  
Exchange Reactions ◽  
Nmr Studies ◽  
Nmr Parameters ◽  
Paramagnetic Metal

The possible effects of paramagnetic relaxation on the apparent volumes of activation for exchange reactions in solution, as measured by NMR at high pressures, are considered. Two model paramagnetic systems that do not undergo ligand exchange on the NMR time scale were examined: tri(acetylacetonato)chromium(III) in various perdeuterated solvents, and tris(ethylenediamine)nickel(II) ion in ethylenediamine solvent. No pressure dependence was discernible up to 200 MPa for the chemical shifts of 1H (exemplifying nuclei of spin 1/2) in the Cr(III) complex, or of solvent 14N (representing quadrupolar nuclei) in the Ni(II)–ethylenediamine case. The line widths Δv1/2, however, were significantly dependent on pressure. For 1H in the Cr complex, the increase of Δv1/2 with pressure was less than expected from the theory of scalar interactions, and was small enough to imply that any contribution from this source to the observed volume of activation in exchanging systems may be neglected. For 14N in liquid ethylenediamine, the increase of Δv1/2 with pressure was significantly greater when a paramagnetic solute was present. Thus, before the observed Δv1/2 at a pressure P (in MPa) measured by the NMR of a quadrupolar nucleus can be used to obtain a chemical exchange rate for a paramagnetic solute, it should be reduced by an amount Δv1/20 exp{θ(P − 0.1)(ΔVV‡/RT + κ)}, where ΔVV‡ is the activation volume for viscous flow and κ the compressibility of the solvent, Δv1/20 is the linewidth at 0.1 MPa in the absence of chemical exchange, and θ is a scaling factor between 0 and 1. The factors Δv1/20 and θ(ΔVV‡/RT + κ) are obtainable from measurements with a chemically equivalent, nonexchanging, paramagnetic solute.

NMR studies on the ligand exchange reactions between diaryl tellurides and phenyllithium: Detection of hypervalent triaryl tellurium ate complexes

1992 ◽  
Vol 3 (4) ◽  
pp. 423-429 ◽  
Author(s):  
Satoshi Ogawa ◽  
Yutaka Masutomi ◽  
Naomichi Furukawa ◽  
Tomoki Erata
Keyword(s):  
Ligand Exchange ◽  
Exchange Reactions ◽  
Nmr Studies

High pressure NMR studies on ligand exchange reactions in the equatorial sites of [VO(L)5]2+ (L=acetonitrile, N,N-dimethylformamide, and N,N-dimethylacetamide)

1999 ◽  
Vol 294 (1) ◽  
pp. 119-122 ◽  
Author(s):  
Jung-Sung Kim ◽  
Takaaki Matsuda ◽  
Masayuki Harada ◽  
Seong-Yun Kim ◽  
Yoon-Yul Park ◽  
...  
Keyword(s):  
High Pressure ◽  
Ligand Exchange ◽  
Exchange Reactions ◽  
Nmr Studies

scholarly journals Laser Irradiation NMR Studies of Photo-induced Effect on the Ligand Exchange Reactions of Uranium(VI) Complexes.

1992 ◽  
pp. 951-955
Author(s):  
Masayuki HARADA ◽  
Satoshi SAKAMAKI ◽  
Takehito YAMAGUCHI ◽  
Hiroshi TOMIYASU
Keyword(s):  
Laser Irradiation ◽  
Ligand Exchange ◽  
Exchange Reactions ◽  
Nmr Studies

Voltammetric Studies of Some Novel Fe(III) Complexes with Quadridentate Ligands. The Axial Ligand-Exchange Reactions in DMF and DMSO

1995 ◽  
Vol 60 (7) ◽  
pp. 1140-1157 ◽  
Author(s):  
Ljiljana S. Jovanovic ◽  
Luka J. Bjelica
Keyword(s):  
Oxidation State ◽  
Chemical Reactions ◽  
Ligand Exchange ◽  
Kinetic Data ◽  
Central Atom ◽  
Axial Ligand ◽  
Exchange Reactions ◽  
Ligand Effect ◽  
Condensation Products ◽  
Voltammetric Studies

The electrochemistry of four novel Fe(III) complexes of the type [Fe(L)Cl], involving quadridentate ligands based on the condensation products of benzoylacetone-S-methylisothiosemicarbazone with salicylaldehyde, 5-chlorosalicylaldehyde, 3,5-dichlorosalicylaldehyde or 5-nitrosalicylaldehyde, was studied in DMF and DMSO at a GC electrode. All complexes undergo a two-step one-electron reductions, usually complicated by chemical reactions. In solutions containing Cl-, the ligand-exchange reactions Cl--DMF and Cl--DMSO take place. Stability of the chloride-containing complexes was discussed in terms of the coordinated ligand effect, oxidation state of the central atom and, in particular, of the donor effect of the solvent. Some relevant kinetic data were calculated.

Sign in / Sign up

Export Citation Format

Share Document