Acta Chimica Slovaca (ACS) publishes papers on fundamental and applied aspects of chemistry, biochemistry, chemical technology, chemical engineering and process control, biotechnology and food technology. Welcome are also topics which include chemical aspects of materials, physical chemistry and chemical physics, analytical chemistry, macromolecular chemistry and biomedical engineering.

Reaction mode of catalytic styrene oxidation using a bis-semicarbazide hexaazamacrocyclic Cu complex

Martin Breza *

Department of Physical Chemistry, Faculty of Chemical and Food Technology STU, Radlinskeho 9, SK-81237 Bratislava, Slovakia

E-mail: * martin.breza@stuba.sk

Abstract: Catalytic styrene Ph-CH=CH2 oxidation is assumed to be a simple reaction procedure; however, its details require further systematic research. Using quantum-chemical treatment, relevant intermediates have been investigated in various charge and spin states of alternative reaction pathways of styrene oxidation by hydroperoxyl using the [CuL]- catalyst, where H2L = trans-2,9-dibutyl-7,14-dimethyl-5,12-di(4-methoxyphenyl)-1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-dione. Within reaction pathway A, the neutral hydroperoxyl radical is bonded to Cu to form 2[CuL(OOH)]-. Subsequent addition of neutral styrene results in the formation of 2{[CuL(OH)](Ph-CH2-CHO)}-. Reaction pathway B starts with the initial non-radical formation of the π-complex 1[CuL(Ph-CH=CH2)]- which is problematic due to its endothermic character. Subsequent addition of a hydroperoxyl radical leads to 2{CuL[Ph-CH(OOH)-CH2]}- and its oxidation leads to the separation of Ph-CH(OOH)-CH2. The exothermic reaction path A is preferred over the endothermic reaction path B.

Keywords: B3LYP hybrid functional; broken symmetry treatment; Cu oxidation state; electronic structure; geometry optimization

Acta Chimica Slovaca, Vol. 18, No. 1, 2025, pp. 91—107, DOI: 10.2478/acs-2025-0010