Stabilisation of tetrabromo- and tetrachlorosemiquinone (bromanil and chloranil) anion radicals in crystals

Molčanov, Krešimir; Kojić-Prodić, Biserka; Babić, Darko; Žilić, Dijana; Rakvin, Boris (2011) Stabilisation of tetrabromo- and tetrachlorosemiquinone (bromanil and chloranil) anion radicals in crystals. CrystEngComm, 13 (16). pp. 5170-5178. ISSN 1466-8033

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Abstract

Crystal structures of alkali salts of tetrahalogenosemiquinone anion radical acetone solvates and their solvent-free salts are determined. p-Semiquinone anion radical reveals enhanced aromaticity of the ring compared to the quinone. A pair of pi-stacked radical anion (p-semiquinone) rings occurs in crystal structures of potassium and rubidium salts of tetrachlorosemiquinone anion acetone solvates and their potassium tetrabromo analogue. The ring centroid separation distances are about 3.2 A and carbon-carbon contacts between the contiguous rings are 0.3 A shorter than the sum of van der Waals radii. The spin-coupling of the two unpaired electrons between the two anion radical rings (forming a stacked dimer) correlates with the diamagnetic property of the crystals. Magnetic properties of alkali salts of tetrahalogenosemiquinone anion radical acetone solvates were examined by electron paramagnetic resonance spectroscopy.

Item Type:	Article
Uncontrolled Keywords:	semiquinone radical anion; pi-stacking; chloranil; bromanil; magnetic properties
Subjects:	NATURAL SCIENCES > Chemistry > Physical Chemistry NATURAL SCIENCES > Chemistry > Inorganic Chemistry NATURAL SCIENCES > Chemistry > Organic Chemistry
Divisions:	Division of Physical Chemistry
Projects:	Project title Project leader Project code Project type Protein-ligand interactions at atomic level (Protein-ligand međudjelovanja na atomnoj razini)- Marija Luić 098-1191344-2943 MZOS Design, synthesis and properties of organic ligands and their metal complexes (Dizajn, sinteza i svojstva organskih liganada i njihovih metalnih kompleksa)- Manda Ćurić 098-0982915-2950 MZOS Molecular structure and dynamics in systems containing paramagnetic particles (Molekulska struktura i dinamika sustava s paramagnetskim česticama)- Marina Ilakovac-Kveder 098-0982915-2939 MZOS
Depositing User:	Darko Babić
Date Deposited:	23 Oct 2012 14:19
URI:	http://fulir.irb.hr/id/eprint/436
DOI:	10.1039/C1CE05513E

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