Coordination Compounds of Indium. Part XIX. Ligand Exchange Studies with Indium(III) Complexes of Trifluoromethyl-β-diketonates

1972 ◽  
Vol 50 (24) ◽  
pp. 3950-3957 ◽  
Author(s):  
Mrs. G. M. Tanner ◽  
D. G. Tuck ◽  
E. J. Wells
Keyword(s):  
Ligand Exchange ◽  
Coordination Compounds ◽  
Free Ligand ◽  
Intramolecular Proton Transfer ◽  
Zero Order ◽  
Monodentate Ligand ◽  
Ligand Exchange Reaction ◽  
First Order ◽  
Stereochemical Properties ◽  
Coalescence Temperature

The ligand exchange reaction between InL3 con plexes (L = CF3•CO•CH•CO•R− anion; R = methyl, i-butyl, phenyl, 2-naphthyl, and 2-thienyl) and excess free ligand (HL) has been studied in the solvents diisopropyl ketone, acetonitrile, benzene, and dimethylsulfoxide. Studies of the lifetimes of the reactants as obtained from their 19F n.m.r. line-widths show that the exchange is first order in InL3 concentration, but zero order in free ligand concentration. The coalescence temperature for the collapse of the n.m.r. 19F chemical shift between free and complexed ligand (~50 Hz) yields ΔG≠ for the exchange. The results are in agreement with the known stereochemical properties of indium(III) complexes. The rate-controlling process in the exchange is identified as the. rotation of one monodentate ligand about a partial double bond prior to intramolecular proton transfer to a second monodentate ligand.

Coordination Compounds of Indium. Part XXVI. Ligand Exchange Studies with Trifluoromethyl-β-diketonato(dimethyl)indium(III) compounds

1974 ◽  
Vol 52 (23) ◽  
pp. 3944-3949 ◽  
Author(s):  
H. L. Chung ◽  
D. G. Tuck
Keyword(s):  
Double Bond ◽  
Proton Transfer ◽  
Ligand Exchange ◽  
Coordination Compounds ◽  
Intramolecular Proton Transfer ◽  
Free Energies ◽  
Monodentate Ligand ◽  
First Order ◽  
Coalescence Temperature

The ligand exchange between Me2InL and HL (L = CF3.CO.CH.CO.R− anion; R = methyl or t-butyl) has been studied by 19F n.m.r. spectroscopy, using benzene and di-isobutylketone as solvents. The exchange is first order in both Me2InL and HL. Activation free energies were derived from measurements of the coalescence temperature. The results are compared with those of earlier studies. The rate-controlling process in the exchange is identified as the rotation of one monodentate diketonate ligand about a partial double bond prior to intramolecular proton transfer to a second monodentate ligand.

Polymérisation du norbornène par des amorceurs au ruthénium. Etude cinétique de la réaction

1980 ◽  
Vol 58 (24) ◽  
pp. 2813-2818 ◽  
Author(s):  
Charles Tanielian ◽  
Alain Kiennemann ◽  
Temel Ösparpucu
Keyword(s):  
Kinetic Parameters ◽  
Homogeneous Catalysis ◽  
Reaction Mechanisms ◽  
Ligand Exchange ◽  
Alcohol Concentration ◽  
Zero Order ◽  
Slow Step ◽  
Variable Order ◽  
First Order ◽  
Initiation Step

The kinetic parameters for the polymerisation reaction of norbornene with RuCl3•3H2O, and RuCl2(PΦ3)3 using homogeneous catalysis have been determined (first-order with respect to two initiators, zero-order with respect to the monomer with RuCl3•3H2O, and variable order with RuCl2(PΦ3)3: Ea 6.2 kcal/mol for RuCl2(PΦ3)3 and 22.8 for RuCl3•3H2O) and leads us to propose different reaction mechanisms for the polymerisation starting from the two initiators, at least for the initiation step. With RuCl2(PΦ3)3 the slow step of the reaction is the metathesis whereas with RuCl3•3H2O the slow step is a ligand exchange at the initiator involving solvent (alcohol) by a dissociative or associative mechanism. This slow step is confirmed by a study of varying alcohol concentration and initiator aging. [Journal translation]

scholarly journals Kinetics of ligand exchange between a uranium(IV) β-diketonate and free β-diketone

1977 ◽  
Vol 55 (20) ◽  
pp. 3559-3561 ◽  
Author(s):  
G. Folcher ◽  
N. Keller ◽  
C. Kiener ◽  
J. Paris
Keyword(s):  
Ligand Exchange ◽  
Free Ligand ◽  
Exchange Mechanism ◽  
First Order ◽  
H Nmr ◽  
Coordination Site ◽  
Exchange Kinetics ◽  
Kinetics Of

The intermolecular ligand exchange kinetics between a uranium(IV) β-diketonate and free β-diketone were studied by 1H nmr as a function of temperature and concentration. The reaction was found to be of first order in both chelate and free ligand. The results suggest that the exchange mechanism involves a ninth coordination site in the uranium(IV) chelate.

Nuclear magnetic resonance study of ligand exchange on hexakis(1,1,3,3-tetramethylurea)yttrium(III)

1981 ◽  
Vol 34 (3) ◽  
pp. 495 ◽  
Author(s):  
DL Pisaniello ◽  
SF Lincoln ◽  
EH Williams ◽  
AJ Jones
Keyword(s):  
Ligand Exchange ◽  
Free Ligand ◽  
Nuclear Magnetic Resonance Study ◽  
Monodentate Ligand ◽  
Dissociative Mechanism ◽  
Complex Stability Constant ◽  
Typical Data ◽  
Encounter Complex ◽  
Fast Exchange ◽  
Scale Down

The first reported direct study of monodentate ligand exchange on yttrium(III) shows the rate of 1,1,3,3-tetramethylurea exchange on [Y {O=C(NMe2)2}6]3+ to be independent of free ligand concentration consistent with the operation of either a dissociative mechanism or an interchange mechanism where the encounter complex stability constant is ≥ 300. Typical data from this 270-MHz 1H n.m.r. study, where rate of ligand exchange = kex 6[Y {O=C(NMe2)2}63+] are as follows: kex(250 K) = 25�1 s-1, ΔH‡ = 27.1 � 0.5 kJ mol-1 and ΔS‡ = -108 � 2 J K-1 mol-1 for a CD3CN solution in which [Y{O=C(NMe2)2}63+] and free [O=C(NMe2)2] are 0.0039 and 0.028 mol dm-3 respectively. The preparations of [Y(ligand)6] (ClO4)3 where the ligand is O=C(NMe2)2, O=C(Me)(NHMe), O=C(Me)(NMe2), or O=C(Me)(NEt2) are also reported. Solutions of the latter three species and their respective ligands exhibit spectra consistent with ligand exchange being in the fast exchange limit of the n.m.r. time scale down to the lowest accessible temperatures.

scholarly journals Ligand Exchange Kinetics of 2,2’-Bipyridine with Nitrilotriacetatonickelate(II)

2018 ◽  
Vol 6 (2) ◽  
pp. 71-75
Author(s):  
Larry H Kolopajlo ◽  
Shelby Coleman
Keyword(s):  
Rate Constant ◽  
Ligand Exchange ◽  
Order Conditions ◽  
Hydrogen Ion ◽  
Ligand Exchange Reaction ◽  
First Order ◽  
Exchange Kinetics ◽  
Pseudo First Order ◽  
Ph Range ◽  
Kinetics Of

The kinetics of the ligand exchange reaction between 2,2’-bipyridine (bipy) and NiNTA- was studied over the pH range 4.7 to 7.5 at 25.0 0C and an ionic strength of 0.10 M by following the formation of Ni(bipy)3 product at 307 nm. All reactions were run under pseudo-first order conditions with a [bipy]/[NiNTA-] ratio of at least 20. The reaction is first-order with respect to each of NiNTA- and to bipy. The reaction is also accelerated by hydrogen ion. The rate constant for the hydrogen ion unassisted addition of bipy to NiNTA- is 0.671 M-1 s-1. The reaction is also first-order in hydrogen ion with a rate constant for the hydrogen ion assisted addition of bipy to NiNTA- is 9.45 x 104 M-2 s-1. A dissociative type mechanism accelerated by hydrogen ion is proposed. The work has significance by showing that NiEDDA and NiNTA, both aminopolyacrboxylate complexes react by the same mechanism.

Ligand exchange reactions of vanadium(III) β diketonate complexes

1978 ◽  
Vol 56 (7) ◽  
pp. 1012-1015 ◽  
Author(s):  
A. J. C. Nixon ◽  
D. R. Eaton
Keyword(s):  
Ligand Exchange ◽  
Zero Order ◽  
Second Order ◽  
Exchange Reactions ◽  
Rate Law ◽  
First Order ◽  
Kinetics Of ◽  
Incoming Ligand

The kinetics of ligand exchange reactions of V(III) β diketonates have been studied. The replacement of acetylacetone by hexafluoroacetylacetone involves a rate law with both first- and second-order terms in the incoming ligand. The replacement of acetylacetone by deuteroacetyl-acetone involves terms zero-order and first-order in the incoming ligand. Both reactions are markedly catalyzed by acids and inhibited by bases. A mechanism involving a dangling ligand intermediate is suggested. The rates of ligand exchange are much less than the rates of isomerization.

Synthesis and Photochemical Properties of Re(I) Tricarbonyl Complexes Bound to Thione and Thiazole-2-ylidene Ligands

2020 ◽  
Author(s):  
Matthew Stout ◽  
Brian Skelton ◽  
Alexandre N. Sobolev ◽  
Paolo Raiteri ◽  
Massimiliano Massi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ligand Exchange ◽  
Ligand Substitution ◽  
Bidentate Ligand ◽  
The Other ◽  
Ligand Exchange Reaction ◽  
Multiple Products ◽  
Ligand Charge Transfer ◽  
Photochemical Properties

<p>Three Re(I) tricarbonyl complexes, with general formulation Re(N^L)(CO)<sub>3</sub>X (where N^L is a bidentate ligand containing a pyridine functionalized in the position 2 with a thione or a thiazol-2-ylidene group and X is either chloro or bromo) were synthesized and their reactivity explored in terms of solvent-dependent ligand substitution, both in the ground and excited states. When dissolved in acetonitrile, the complexes bound to the thione ligand underwent ligand exchange with the solvent resulting in the formation of Re(NCMe)<sub>2</sub>(CO)<sub>3</sub>X. The exchange was found to be reversible, and the starting complex was reformed upon removal of the solvent. On the other hand, the complexes appeared inert in dichloromethane or acetone. Conversely, the complex bound to the thiazole-2-ylidene ligand did not display any ligand exchange reaction in the dark, but underwent photoactivated ligand substitution when excited to its lowest metal-to-ligand charge transfer manifold. Photolysis of this complex in acetonitrile generated multiple products, including Re(I) tricarbonyl and dicarbonyl solvato-complexes as well as free thiazole-2-ylidene ligand.</p>

Kinetics of catalytic reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst

1983 ◽  
Vol 48 (11) ◽  
pp. 3202-3208 ◽  
Author(s):  
Zdeněk Musil ◽  
Vladimír Pour
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxide ◽  
Rate Equation ◽  
Catalytic Reduction ◽  
Zero Order ◽  
Spectroscopic Measurements ◽  
First Order ◽  
Ir Spectroscopic ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetics of the reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst (8.36 mass % CuO) were determined at temperatures between 413 and 473 K. The reaction was found to be first order in NO and zero order in CO. The observed kinetics are consistent with a rate equation derived from a mechanism proposed on the basis of IR spectroscopic measurements.

F−(H2O)+CH3I ligand exchange reaction dynamics

2020 ◽  
Vol 33 (2) ◽  
pp. 210-216
Author(s):  
Björn Bastian ◽  
Tim Michaelsen ◽  
Milan Ončák ◽  
Jennifer Meyer ◽  
Roland Wester
Keyword(s):  
Exchange Reaction ◽  
Ligand Exchange ◽  
Reaction Dynamics ◽  
Ligand Exchange Reaction
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