Effect of Hydrogen Bonding on the Pyramidalization of the Amino Group: Structure of 3,4-diaminobenzamidinium Chloride

Stolić, Ivana and Bajić, Miroslav and Matković-Čalogović, Dubravka (2013) Effect of Hydrogen Bonding on the Pyramidalization of the Amino Group: Structure of 3,4-diaminobenzamidinium Chloride. Croatica Chemica Acta, 86 (2). pp. 193-199. ISSN 0011-1643

[img]
Preview
PDF - Published Version
Language: English

Download (3MB) | Preview

Abstract

3,4-diaminobenzamidinium was synthesized and spectroscopically and structurally characterized,both at room temperature and at 150 K. The crystal structure consists of two 3,4-diaminobenzamidinium cations and two chloride anions. The planar amidinium group is inclined by 35.35(5)° and 28.96(7)° in respect to the diaminobenzene moiety in the two crystallographically independent cations. The ions are interconnected by a large network of hydrogen bonds into a threedimensional structure. Pyramidalization of the amino group in relation to the hydrogen bond length in which the amino group is an acceptor is analized. Two amino groups are acceptors of N–H···N hydrogen bonds of 2.9565(14) Å and 2.9654(15) Å resulting in pyramidalization of 340(1)° and 337(1)°, respectively (the sum of the amino group bond angles is given as a measure of pyramidalization). A very weak hydrogen bond to one amino group results in a very flat pyramid (351(1)°), while one amino group is not acceptor of a hydrogen bonds and it is planar. The resonance effect has influence on the planar amino groups resulting in a shorter C–N(amino group) bond length than in the pyramidalized ones.

Item Type: Article
Keywords: pyramidalization of the amino group; 3,4-diaminobenzamidinium chloride; X-ray single crystal structure analysis
Date: 2013
Subjects: NATURAL SCIENCES > Chemistry
Divisions: Faculty of Science > Department of Chemistry
Publisher: Hrvatsko kemijsko društvo
Related URLs:
Depositing User: Branka Maravic
Date Deposited: 24 Apr 2014 14:09
Last Modified: 24 Apr 2014 14:09
URI: http://digre.pmf.unizg.hr/id/eprint/950

Actions (login required)

View Item View Item