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Title: Decreased overall basicity of a series of new N,N'-bis(carboxymethyl) macrocylcic ether-bis(lactone) ligands derived from EDTA and the ring size effect on the stability constants of their lanthanide complexes

Abstract

In order to examine the effects of positions of the nitrogen donor atoms and the relative coordination sites of the two carboxylate groups on lanthanide complexation in the study of the characteristics of both open-chain and macrocyclic ligands for the preparation of novel metal-ion selective reagents, a series of N, N'-bis(carboxymethyl)macrocyclic ether-bis(lactone)ligands derived from ethylenediaminetetraacetic acid have been prepared and characterized. The ligand protonation constants and the lanthanide complex formation constants have been determined and are reported here. 14 references, 2 figures, 2 tables.

Authors:
; ;
Publication Date:
Research Org.:
Univ. of Texas, El Paso (USA)
OSTI Identifier:
5776306
DOE Contract Number:
FG05-84ER13292
Resource Type:
Journal Article
Resource Relation:
Journal Name: Inorg. Chem.; (United States); Journal Volume: 27:5
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; HETEROCYCLIC COMPOUNDS; CHEMICAL PREPARATION; ORGANIC NITROGEN COMPOUNDS; POLYETHYLENE GLYCOLS; RARE EARTH COMPLEXES; CHEMICAL REACTION KINETICS; EDTA; EXPERIMENTAL DATA; ALCOHOLS; AMINO ACIDS; CARBOXYLIC ACIDS; CHELATING AGENTS; COMPLEXES; DATA; GLYCOLS; HYDROXY COMPOUNDS; INFORMATION; KINETICS; NUMERICAL DATA; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC POLYMERS; POLYMERS; REACTION KINETICS; SYNTHESIS; 400201* - Chemical & Physicochemical Properties

Citation Formats

Chang, C.A., Chang, P.H.L., and Qin, S.Y. Decreased overall basicity of a series of new N,N'-bis(carboxymethyl) macrocylcic ether-bis(lactone) ligands derived from EDTA and the ring size effect on the stability constants of their lanthanide complexes. United States: N. p., 1988. Web. doi:10.1021/ic00278a038.
Chang, C.A., Chang, P.H.L., & Qin, S.Y. Decreased overall basicity of a series of new N,N'-bis(carboxymethyl) macrocylcic ether-bis(lactone) ligands derived from EDTA and the ring size effect on the stability constants of their lanthanide complexes. United States. doi:10.1021/ic00278a038.
Chang, C.A., Chang, P.H.L., and Qin, S.Y. Wed . "Decreased overall basicity of a series of new N,N'-bis(carboxymethyl) macrocylcic ether-bis(lactone) ligands derived from EDTA and the ring size effect on the stability constants of their lanthanide complexes". United States. doi:10.1021/ic00278a038.
@article{osti_5776306,
title = {Decreased overall basicity of a series of new N,N'-bis(carboxymethyl) macrocylcic ether-bis(lactone) ligands derived from EDTA and the ring size effect on the stability constants of their lanthanide complexes},
author = {Chang, C.A. and Chang, P.H.L. and Qin, S.Y.},
abstractNote = {In order to examine the effects of positions of the nitrogen donor atoms and the relative coordination sites of the two carboxylate groups on lanthanide complexation in the study of the characteristics of both open-chain and macrocyclic ligands for the preparation of novel metal-ion selective reagents, a series of N, N'-bis(carboxymethyl)macrocyclic ether-bis(lactone)ligands derived from ethylenediaminetetraacetic acid have been prepared and characterized. The ligand protonation constants and the lanthanide complex formation constants have been determined and are reported here. 14 references, 2 figures, 2 tables.},
doi = {10.1021/ic00278a038},
journal = {Inorg. Chem.; (United States)},
number = ,
volume = 27:5,
place = {United States},
year = {Wed Mar 09 00:00:00 EST 1988},
month = {Wed Mar 09 00:00:00 EST 1988}
}
  • Hydrolysis of the product formed by reacting 2 equiv of 2-(lithiomethylene)-6-methylpyridine with trimethylacetyl chloride gives the alcohol HOC(CMe{sub 3})(2-CH{sub 2}NC{sub 5}H{sub 3}Me-6){sub 2}, (1) (HOR), in 44% yield. Three equivalents of (1) reacts with Yb[N(SiMe{sub 3}){sub 2}]{sub 3} to form Yb(OR){sub 3} (2a). The analogous 2 equiv reaction generates Yb(OR){sub 2}[N(SiMe{sub 3}){sub 2}], (3). X-ray diffraction studies were successful on (3) and on (2b), the Sm analog of (2a). Two of the alkoxide ligands in Sm(OR){sub 3}, (2b), are bidentate such that each has an uncomplexed nitrogen donor atom oriented away from the metal. These chelates occupy basal positions inmore » the distorted square pyramidal geometry around the metal center in (2b) such that the oxygen donors are trans. The axial position is occupied by the third alkoxide which is monodentate through its oxygen donor atom. This leaves a total of four unattached pyridine functionalities available for further coordination. The ligand arrangement in (3) is very similiar to that in (2b) except that the monodentate alkoxide in (2b) is replaced by a N(SiMe{sub 3}){sub 2} group. A ligand fragmentation product, (R{prime}O){sub 2}Sm({mu}-OR){sub 2}Na, (4), containing the chelating bidentate pyridine enolate ligand [OC(CMe{sub 3})(=2CHNC{sub 5}H{sub 3}Me-6)](OR{prime}), formed by loss of a 2,6-dimethylpyridine group from OR, was also isolated in the course of these studies. Each OR ligand in (4) has its oxygen atom bridging Sm and Na, one pyridine nitrogen coordinated to Na, and one pyridine nitrogen which is not connected to any metal. The samarium center in (4) has a distorted octahedral geometry generated by two chelating R{prime}O groups and the two bridging oxygens from the OR groups. The nitrogen donor atoms of the R{prime}O groups have a cis orientation and are trans to the bridging ligands.« less
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