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Title: New series of chelated organochromium(III) complexes. [1,4,8,12-Tetraazacyclopentaedecane]

Abstract

A kinetic and mechanistic study of the preparation of a new family of chelated organochromium(III) complexes was completed. These species were formed from organic halides and (1,4,8,12 tetraazacyclopentadecane) chromium(II) by a mechanism which involves initial halogen atom abstraction followed by subsequent radical capture by another Cr(II) complex. The rates of reaction follow the pattern expected for a S/sub H/2 process, 3/sup 0/ > 2/sup 0/ > 1/sup 0/ and I > Br > Cl. These organochromium(III) chelate complexes have the trans configuration. Electrophilic cleavage reactions by mercuric and methylmercuric ions were studied. These reactions proceed by a S/sub E/2 (open) mechanism with the reaction rates being approx. 100 times slower for the chelated species. The activation parameters were determined for five reactions. The crystal structure of (trans-chloroaquo(1,4,8,12-tetraazacyclopentadecane)chromium(III))diiodide-dihydrate is also reported. The macrocycle assumes the lowest energy conformation as predicted by strain energy calculations.

Authors:
Publication Date:
Research Org.:
Ames Lab., IA (USA)
OSTI Identifier:
6378118
Report Number(s):
IS-T-848
DOE Contract Number:
W-7405-ENG-82
Resource Type:
Technical Report
Resource Relation:
Other Information: Thesis
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHROMIUM COMPLEXES; CHEMICAL REACTION KINETICS; AMINES; CHELATES; CHEMICAL PREPARATION; CRYSTAL STRUCTURE; EXPERIMENTAL DATA; ISOLATED VALUES; MOLECULAR STRUCTURE; COMPLEXES; DATA; DATA FORMS; INFORMATION; KINETICS; NUMERICAL DATA; ORGANIC COMPOUNDS; REACTION KINETICS; SYNTHESIS; TRANSITION ELEMENT COMPLEXES; 400201* - Chemical & Physicochemical Properties

Citation Formats

Samuels, G.J. New series of chelated organochromium(III) complexes. [1,4,8,12-Tetraazacyclopentaedecane]. United States: N. p., 1979. Web. doi:10.2172/6378118.
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Samuels, G.J. New series of chelated organochromium(III) complexes. [1,4,8,12-Tetraazacyclopentaedecane]. United States. doi:10.2172/6378118.
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Samuels, G.J. Mon . "New series of chelated organochromium(III) complexes. [1,4,8,12-Tetraazacyclopentaedecane]". United States. doi:10.2172/6378118. https://www.osti.gov/servlets/purl/6378118.
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@article{osti_6378118,
title = {New series of chelated organochromium(III) complexes. [1,4,8,12-Tetraazacyclopentaedecane]},
author = {Samuels, G.J.},
abstractNote = {A kinetic and mechanistic study of the preparation of a new family of chelated organochromium(III) complexes was completed. These species were formed from organic halides and (1,4,8,12 tetraazacyclopentadecane) chromium(II) by a mechanism which involves initial halogen atom abstraction followed by subsequent radical capture by another Cr(II) complex. The rates of reaction follow the pattern expected for a S/sub H/2 process, 3/sup 0/ > 2/sup 0/ > 1/sup 0/ and I > Br > Cl. These organochromium(III) chelate complexes have the trans configuration. Electrophilic cleavage reactions by mercuric and methylmercuric ions were studied. These reactions proceed by a S/sub E/2 (open) mechanism with the reaction rates being approx. 100 times slower for the chelated species. The activation parameters were determined for five reactions. The crystal structure of (trans-chloroaquo(1,4,8,12-tetraazacyclopentadecane)chromium(III))diiodide-dihydrate is also reported. The macrocycle assumes the lowest energy conformation as predicted by strain energy calculations.},
doi = {10.2172/6378118},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 1979},
month = {Mon Jan 01 00:00:00 EST 1979}
}
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Technical Report:
View Technical Report (4.16 MB)
DOI:  10.2172/6378118
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