Bis(methylphosphonic Acid) Derivatives of 1,4,8,11-Tetraazacyclotetradecane (Cyclam). Synthesis, Crystal and Molecular Structures, and Solution Properties

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Title:Bis(methylphosphonic Acid) Derivatives of 1,4,8,11-Tetraazacyclotetradecane (Cyclam). Synthesis, Crystal and Molecular Structures, and Solution Properties
Creators:
Kotek, Jan
Vojtíšek, Pavel
Císařová, Ivana
Hermann, Petr
Jurečka, Petr
Rohovec, Jan
Lukeš, Ivan
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 65, 8, pp. 1289-1316
Uncontrolled Keywords:Potentiometry, Protonation constants, Conformation analysis, Macrocycles, Cyclam, Tetrazacyclotetradecane, Azacrown compounds, Phosphonic acids, Basicity, Crystal structure, Hydrogen bonds, NMR spectroscopy

Abstract

Cyclam derivatives with methylphosphonic acid arms in position 1,8 and substituent R = H, Me, CH<sub>2</sub>Ph in positions 4 and 11 are synthesised by Mannich reaction of an appropriate cyclam derivative, formaldehyde and phosphonic acid/diethyl phosphite followed by removal of protecting benzyl groups from nitrogen atoms. Mono(methylphosphonic acid) derivative of cyclam can be obtained by a similar route. Crystal structures of four phosphonic acid derivatives show the same ring conformation and orientation pendants due to strong intramolecular hydrogen bonds between phosphonate oxygen atoms and protonated nitrogen atoms adjacent over ethylene chains. The hydrogen bonds are stable even in aqueous solution. Activation parameters for destabilisation of the conformation are estimated from temperature-dependent NMR measurement. The protonation constants determined confirm the expected high basicity of the compounds and its dependence on the nitrogen atom substituents. The enhanced basicity of the nitrogen atoms non-bonded to methylenephosphonic acid moiety, is explained by the presence of the strong hydrogen bonds. <p>

Title:Bis(methylphosphonic Acid) Derivatives of 1,4,8,11-Tetraazacyclotetradecane (Cyclam). Synthesis, Crystal and Molecular Structures, and Solution Properties
Creators:
Kotek, Jan
Vojtíšek, Pavel
Císařová, Ivana
Hermann, Petr
Jurečka, Petr
Rohovec, Jan
Lukeš, Ivan
Uncontrolled Keywords:Potentiometry, Protonation constants, Conformation analysis, Macrocycles, Cyclam, Tetrazacyclotetradecane, Azacrown compounds, Phosphonic acids, Basicity, Crystal structure, Hydrogen bonds, NMR spectroscopy
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:65
Number:8
Page Range:pp. 1289-1316
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20001289UNSPECIFIED
ID Code:1717
Item Type:Article
Deposited On:06 Feb 2009 17:12
Last Modified:06 Feb 2009 16:12

Citation

Kotek, Jan; Vojtíšek, Pavel; Císařová, Ivana; Hermann, Petr; Jurečka, Petr; Rohovec, Jan; Lukeš, Ivan (2000) Bis(methylphosphonic Acid) Derivatives of 1,4,8,11-Tetraazacyclotetradecane (Cyclam). Synthesis, Crystal and Molecular Structures, and Solution Properties. Collection of Czechoslovak Chemical Communications, 65 (8). pp. 1289-1316. ISSN 0010-0765

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