Kinetics and Mechanism of Metal-Substitution Reaction of Homodinuclear Mercury(II) Porphyrin with Zinc(II) with Particular Reference to a Heterodinuclear Metalloporphyrin Intermediate

1995 ◽  
Vol 34 (26) ◽  
pp. 6492-6496 ◽  
Author(s):  
Masaaki Tabata ◽  
Wakako Miyata ◽  
Nurun Nahar
Keyword(s):  
Substitution Reaction ◽  
Kinetics And Mechanism ◽  
Metal Substitution

scholarly journals Synthesis, kinetics and mechanism of nucleophilic substitution in octahedral (cat)2Sn(py)2

2005 ◽  
Vol 70 (12) ◽  
pp. 1389-1393 ◽  
Author(s):  
K.S. Siddiqi ◽  
Shahab Nami
Keyword(s):  
Nucleophilic Substitution ◽  
Rate Constant ◽  
Substitution Reaction ◽  
Molar Conductance ◽  
Chloride Ions ◽  
Kinetics And Mechanism ◽  
Nucleophilic Substitution Reaction ◽  
Nucleophilic Reagents

Dicatecholatodipyridinetin(IV) in nitrobenzene showed an increase in molar conductance with time, suggesting solvation of the complex. In the presence of nucleophilic reagents, such as SOCl2, C6H5COCl and CH3COCl, the conductance increased sharply owing to the substitution of pyridine by chloride ions. The data for the rate constant of solvation (k s) and for nucleophilic substitution (k 1 and k 2) have been calculated and it was found that the solvation is a slower process compared to the substitution by chloride ions, i.e., k1, k 2 > k s. The nucleophilic substitution reaction follows the SN1 mechanism.

scholarly journals Synthesis of Ti3AuC2, Ti3Au2C2 and Ti3IrC2 by noble metal substitution reaction in Ti3SiC2 for high-temperature-stable Ohmic contacts to SiC

2017 ◽  
Vol 16 (8) ◽  
pp. 814-818 ◽  
Author(s):  
Hossein Fashandi ◽  
Martin Dahlqvist ◽  
Jun Lu ◽  
Justinas Palisaitis ◽  
Sergei I. Simak ◽  
...  
Keyword(s):  
High Temperature ◽  
Noble Metal ◽  
Substitution Reaction ◽  
Ohmic Contacts ◽  
Metal Substitution

Trinuclear and Tetranuclear Platinum−Iridium Cluster Complexes:  A Remarkable Metal for Metal Substitution Reaction

1998 ◽  
Vol 17 (12) ◽  
pp. 2433-2439 ◽  
Author(s):  
Brian T. Sterenberg ◽  
Greg J. Spivak ◽  
Glenn P. A. Yap ◽  
Richard J. Puddephatt
Keyword(s):  
Substitution Reaction ◽  
Metal Substitution ◽  
Cluster Complexes

Structure of the Short-Lived Intermediate Formed during the Metal Substitution Reaction of the Mercury(II) Porphyrin Complex with Cobalt(II) Ion in Aqueous Solution Determined by the Stopped-Flow EXAFS Method

1998 ◽  
Vol 53 (4) ◽  
pp. 469-475 ◽  
Author(s):  
Kazuhiko Ozutsumi ◽  
Shintaro Ohnishia ◽  
Hitoshi Ohtaki ◽  
Masaaki Tabatab
Keyword(s):  
Bond Length ◽  
Local Structure ◽  
Substitution Reaction ◽  
Stopped Flow ◽  
Coordination Geometry ◽  
Metal Substitution ◽  
Octahedral Structure ◽  
Coordinate Structure ◽  
Bond Lengths ◽  
Additional Water

The local structure around the cobalt(II) ion in the reaction intermediate formed during the metal substitution reaction of the homodinuclear mercury(II) porphyrin (5,10,15,20-tetrakis(4- sulfonatophenyl)porphyrin; H2tpps4- ) complex with a cobalt(II) ion in an acetate buffer has been determined by the stopped-flow EXAFS method. The structure of the reactant and the product of the above reaction has also been determined by the same method. The coordination geometry around the cobalt(II) ion in the heterodinuclear intermediate, [Hg(tpps)Coll]2- , is six-coordinate octahedral with four additional water and/or acetate oxygen atoms. The Coll-N and Coll-O bond lengths in the intermediate are 212(2) and 221(1) pm, respectively. The product, [Coll(tpps)]4-, has a six-coordinate octahedral structure, the Coll-N and Coll-O bond lengths being 203(1) and 215(1) pm, respectively. The Coll-N bond length in the intermediate is ca. 9 pm longer than that in the product. The Coll-O bond length in the intermediate is also ca. 9 pm longer than that of 212(1) pm in the reactant, the cobalt(II) acetato complex, and ca. 6 pm longer than that in the product. The longer Coll-O bond in the intermediate as compared to those in the reactant and in the product appears to be responsible for the instability of the intermediate. The oxidized product, [Colll(tpps)]3-, has a six-coordinate structure with two additional Colll-O bonds. The Colll-N and Colll-O bond lengths are 189(1) and 197(2) pm, respectively, and are much shorter than those in [Coll(tpps)]4-.

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