The Lewis-acidity of square-planar nickel(II) complexes. II. A kinetic investigation of the addition of substituted phenanthrolines to Bis(O,O-diethylphosphorodithioato-S,S')nickel(II), Bis(O-ethylxanthato)nickel(II) and Bis(4-mercaptopent-3-en-2-onato)nickel(II) in toluene

1977 ◽  
Vol 30 (2) ◽  
pp. 285 ◽  
Author(s):  
MU Fayyaz ◽  
MW Grant
Keyword(s):  
Substituent Effect ◽  
Addition Reaction ◽  
Bond Formation ◽  
Nickel Complexes ◽  
Lewis Acidity ◽  
Stopped Flow ◽  
Kinetic Investigation ◽  
Relative Importance ◽  
Square Planar ◽  
A Minor

The rates of the addition reaction between substituted phenanthrolines and the square-planar nickel complexes bis(O,O-diethyl phosphorodithioato-S,S')nickel(II), Ni(dtp)2, bis(O-ethylxanthato)-nickel(II), Ni(xan)2, and bis(4-mercaptopent-3-en-2-onato)nickel(II), Ni(sacac)2, have been measured in toluene by the stopped-flow technique. For Ni(xan)2, the second-order rate constants, kf, are in the range (1- 8)×105 l. mol-1 s-1, ΔHf‡ is 16�2 kJ mol-1 and there is a significant substituent effect. For Ni(dtp)2, kf is (1-3)×104 l. mol-1 s-1, ΔHf‡ is 24�2 kJmol-1 and there is a minor substituent effect. For Ni(sacac)2, kf is about 5‡102 l. mol-1 s-1, ΔHf‡ is 50 kJ mol-1 and there is no substituent effect. The results are discussed in terms of the relative importance of Ni-N bond formation and displacement of the in-plane ligands in the transition state.

The Lewis-acidity of square-planar nickel(II) complexes. I. A kinetic and thermodynamic study of the reaction of Bis(O,O-diethyl phosphorodithioato-S,S'-)nickel(II) with bidentate nitrogen donors

1976 ◽  
Vol 29 (4) ◽  
pp. 749 ◽  
Author(s):  
MW Grant ◽  
RJ Magee
Keyword(s):  
Nickel Complex ◽  
Addition Reaction ◽  
Order Rate Constant ◽  
Lewis Acidity ◽  
Polar Solvents ◽  
First Order ◽  
Nitrogen Ligands ◽  
Square Planar ◽  
Kinetics Of ◽  
Kinetic And Thermodynamic Study

The kinetics of the addition reaction between bis(O,O-diethyl phosphorodithioato-S,S'-)nicke1(11) and a series of bidentate nitrogen ligands has been examined by stopped-flow techniques. The reactions are first order in ligand and nickel complex with kf, the second-order rate constant, in the range from 103 to 106 1. mol-1 s-1 at 25�C in benzene. Solvent effects on the reaction with 2,2'-bipyridyl are minor. The variation in kf with ligand is discussed in terms of the steric requirements of the ligands, the bulkiest ligand, 2,9-dimethyl-1,l0-phenanthroline, reacting most slowly. For the ligands 1,l0-phenanthroline and 2,2'-bipyridyl in the more polar solvents, successive displacement of the thiophosphate ligands follows the initial addition step.

Dynamic behaviour attributed to chiral carbohydrate substituents of N-heterocyclic carbene ligands in square planar nickel complexes

2011 ◽  
Vol 40 (25) ◽  
pp. 6778 ◽  
Author(s):  
Teppei Shibata ◽  
Satoru Ito ◽  
Matsumi Doe ◽  
Rika Tanaka ◽  
Hideki Hashimoto ◽  
...  
Keyword(s):  
Dynamic Behaviour ◽  
Nickel Complexes ◽  
Carbene Ligands ◽  
Square Planar

Nucleophilic addition at u 3 -alkyne clusters leading to carbon-carbon bond formation

1982 ◽  
Vol 308 (1501) ◽  
pp. 59-66 ◽  
Keyword(s):  
Bond Formation ◽  
Organic Ligand ◽  
Major Product ◽  
Unsaturated Hydrocarbon ◽  
Terminal Alkynes ◽  
Hydrogen Atoms ◽  
Metal Atoms ◽  
Carbon Carbon Bond ◽  
Anionic Species ◽  
A Minor

Reactions of nucleophiles with triosmium carbonyl clusters, especially those containing unsaturated hydrocarbon ligands, are discussed. Attack may be at CO, the metal atoms, at carbon of the organic ligand, or, where there are acidic metal-bound hydrogen atoms, deprotonation to give anionic clusters may occur. New results on the reactions of LiBHEt3 with p3-alkyne clusters of type Os3(CO)10 (RC2R') are considered in the light of the range of possible sites of attack. Protonation of anionic species that are formed gives hydrogenation products with or without the loss of CO. Os3H2(CO)9(RC2R') is usually a minor product, while C-C coupling leads to Os3H(CO)9(CRCR'COH) (in general the major product) and to Os3H(CO)9- (CRCR'CH). With terminal alkynes RC2H H-atom transfer accompanies C-C coupling to give Os3H(CO)9(RC—C =C H 2) in substantial amounts. The initial site of hydride attack (CO, alkyne or metal) is considered in the context of low-temperature 1H n.m.r. results.

scholarly journals Nickel Complexes in C‒P Bond Formation

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5283
Author(s):  
Almaz A. Zagidullin ◽  
Il’yas F. Sakhapov ◽  
Vasili A. Miluykov ◽  
Dmitry G. Yakhvarov
Keyword(s):  
Bond Formation ◽  
Nickel Complexes ◽  
Catalytic Reactions ◽  
Comprehensive Account ◽  
Phosphorus Chemistry

This review is a comprehensive account of reactions with the participation of nickel complexes that result in the formation of carbon–phosphorus (C‒P) bonds. The catalytic and non-catalytic reactions with the participation of nickel complexes as the catalysts and the reagents are described. The various classes of starting compounds and the products formed are discussed individually. The several putative mechanisms of the nickel catalysed reactions are also included, thereby providing insights into both the synthetic and the mechanistic aspects of this phosphorus chemistry.

scholarly journals Michael Addition of Imidazole to α, β -Unsaturated Carbonyl/Cyano Compound

2018 ◽  
Vol 5 (1) ◽  
pp. 18-31
Author(s):  
Seetaram Mohapatra ◽  
Nilofar Baral ◽  
Nilima Priyadarsini Mishra ◽  
Pravati Panda ◽  
Sabita Nayak
Keyword(s):  
Organic Chemistry ◽  
Amino Acids ◽  
Anticancer Agents ◽  
Michael Addition ◽  
Addition Reaction ◽  
Bond Formation ◽  
Conjugate Addition ◽  
Michael Addition Reaction ◽  
Cyano Compounds ◽  
Nitrogen Bond

Introduction: Aza-Michael addition is an important reaction for carbon-nitrogen bond formation in synthetic organic chemistry. Expalantion: Conjugate addition of imidazole to α,β-unsaturated carbonyl/cyano compounds provides significant numbers of the biologically and synthetically interesting products, such as β-amino acids and β-lactams, which have attracted great attention for their use as key intermediates of anticancer agents, antibiotics and other drugs. Conclusion: This review addresses most significant method for the synthesis of N-substituted imidazole derivatives following Michael addition reaction of imidazole to α,β-unsaturated carbonyl/cyano compounds using ionic liquid/base/acid/enzyme as catalysts from year 2007-2017.

scholarly journals Binuclear, High-Valent Nickel Complexes: Ni−Ni Bonds in Aryl-Halogen Bond Formation

2017 ◽  
Vol 129 (13) ◽  
pp. 3689-3693 ◽  
Author(s):  
Justin B. Diccianni ◽  
Chunhua Hu ◽  
Tianning Diao
Keyword(s):  
Halogen Bond ◽  
Bond Formation ◽  
Nickel Complexes ◽  
High Valent

Übergangsmetallkomplexe mit Schwefelliganden, LXXVI Redox- und Additionsreaktionen von Nickelkomplexen mehrzähniger Thioether-Thiolat-Liganden. Röntgenstrukturanalysen von (NMe4)2[Ni(′S2′)2] und [Ni(′S4 – C3′)(PMe3)] / Transition Metal Complexes with Sulfur Ligands, LXXVI Redox and Addition Reactions of Nickel Complexes with Multidentate Thioether-Thiolato Ligands. X-Ray Structure Determinations of (NMe4)2[Ni(′S2′)2] and [Ni(′S4–C3′)(PMe3)]

1991 ◽  
Vol 46 (12) ◽  
pp. 1601-1608 ◽  
Author(s):  
Dieter Sellmann ◽  
Stefan Fünfgelder ◽  
Falk Knoch ◽  
Matthias Moll
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Structure Analysis ◽  
Transition Metal Complexes ◽  
Nickel Complexes ◽  
Addition Reactions ◽  
Coordination Geometry ◽  
X Ray ◽  
Square Planar ◽  
Structure Determinations

In order to elucidate specific properties of nickel sulfur complexes, redox and addition-elimination reactions of [Ni(′OS4')]2, [Ni(′NHS4')]2, [Ni(′S5')], [Ni('S4—C5')], and [Ni('S4—C3')] were investigated ('OS4′ 2' = 2,2'-bis(2-mercaptophenylthio)diethylether(2—), 'NHS4'2- = 2,2'-bis(2-mercaptophenylthio)diethylamine(2—), 'S5'2- = 2,2'-bis(2-mercaptophenylthio)diethylsulfide(2—), 'S4-C5'2- = 1,5-bis(2-mercaptophenylthio)pentane(2—), 'S4—C3'2- = 1,3-bis(2-mercaptophenylthio)propane(2—)).Cyclovoltammetry proves the complexes to be redox inactive between —1.4 and +0.8 V vs. NHE. Above +0.8 V the complexes are irreversibly oxidized, below —1,4 V desalkylation takes place and [Ni(′S,′)2]2- is formed. An X-ray structure analysis was carried out of (NMe4)2[Ni(′S2')2], which shows a planar anion with the Ni center in a nearly perfect square planar coordination. Distances and angles are practically identical to those in the [Ni(′S2')2-] monoanion.The complexes coordinate only phosphines as coligands, but thioether donors simultaneously decoordinate and, dependant of reaction temperature, mono- or trisphosphine complexes are formed. [Ni(′S4—C3')(PMe3)] was characterized by X-ray structure analysis and exhibits a square pyramidal coordination geometry.

Thermal Addition Reaction of Aroylketene with Ethyl Vinyl Ether: Aromatic Substituent Effect on Aroylketene Reactivity

Heterocycles ◽  
1996 ◽  
Vol 43 (11) ◽  
pp. 2457 ◽  
Author(s):  
Takehiro Sano ◽  
Jun Toda ◽  
Toshiaki Saitoh ◽  
Taichi Oyama ◽  
Yoshie Horiguchi
Keyword(s):  
Vinyl Ether ◽  
Substituent Effect ◽  
Addition Reaction ◽  
Ethyl Vinyl Ether ◽  
Ethyl Vinyl ◽  
Aromatic Substituent ◽  
Thermal Addition

Nickel complexes of ligands derived from (o-hydroxyphenyl) dichalcogenide: delocalised redox states of nickel and o-chalcogenophenolate ligands

2019 ◽  
Vol 48 (46) ◽  
pp. 17355-17363 ◽  
Author(s):  
Sridhar Banerjee ◽  
Debobrata Sheet ◽  
Subhash Sarkar ◽  
Partha Halder ◽  
Tapan Kanti Paine
Keyword(s):  
Metal Ion ◽  
Nickel Complexes ◽  
Redox States ◽  
Square Planar

The monoanionic square planar S = 1/2 nickel complexes of dianionic o-chalcogenophenolate ligands display delocalised redox states of the metal ion and ligands.

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