ORIGINAL PAPER Theoretical study of the interaction between molecular oxygen and tetraaza macrocyclic manganese complexes Alexandre Costa 1 & Adilson Luís Pereira Silva 2 & Rommel Bezerra Viana 3 & Auro Atsushi Tanaka 1 & Jaldyr de Jesus Gomes Varela Jr 1 Received: 25 May 2016 /Accepted: 8 August 2016 # Springer-Verlag Berlin Heidelberg 2016 Abstract Theoretical chemistry calculations using the Density Functional Theory (DFT) were carried out to understand the interaction between oxygen (O 2 ) and MnN 4 type manganese-based complexes during the formation of MnN 4 -O 2 adducts. In order to understand how this interaction is affected by different macrocyclic ligands, O 2 was bonded to manganese-porphyrin (MnP), manganese-octamethylporphyrin (MnOMP), manganese-tetraaza[ 14]annulene (MnTAA), manganese-dibenzo [b,i] [1, 4, 8, 11]-tetraaza [14] annulene (MnDBTAA), manganese-2,3,9,10-tetramethyl-1,4,8,11- tetraazacyclotetradeca-1,3,8,10-tetraene ([(tim)Mn] 2+ ), and manganese-2,3,9,10-tetraphenyl-1,4,8,11- tetraazacyclotetradeca-1,3,8,10-tetraene ([(ph-tim)Mn] 2+ ). The binding and activation of the oxygen molecule was facilitated by an increasing trend in the O-O bond lengths and a decreasing one in the O-O vibrational frequency, with preference for the O 2 side-on interaction among MnN 4 macrocycles. The catalytic activities of the MnN 4 complexes toward the O 2 binding process increased in the following order: [(ph-tim)Mn] 2+ < MnP < MnOMP < MnDBTAA < MnTAA < [(tim)Mn] 2+ . Therefore, it was concluded that the [(tim)Mn] 2+ complex was the most active for the binding and activation of molecular oxygen. Keywords Density Functional Theory . Oxygen reduction reaction . Transition metal macrocyclic complex Introduction The oxygen reduction reaction (ORR) is important in many technologies, such as fuel cells, metal-air batteries, and elec- trochemical sensors [1–3]. In recent decades, considerable ef- forts have been made to study the mechanism of the ORR in acidic and alkaline aqueous solutions using different electrode materials [4–8]. The irreversibility of the ORR results in seri- ous energy losses and restrictions on the power of fuel cells, as well as life span limitations. Furthermore, in order to achieve acceptable levels of performance, precious metals such as platinum have been used in the manufacture of electrodes for the reduction of oxygen in aqueous media [9–11]. In attempts to replace platinum electrodes, due to the high cost and low availability of the metal [12], N 4 type macrocy- clic complexes with transition metals such as metallopor phyrins (MPs) and metallophthalocyanines (MPCs) have been investigated for the ORR [13–17]. This was only possible from 1964, when the work of Jasinski [18] showed that cobalt phthalocyanine ([Co II (Pc)]) was catalytically active for the O 2 reduction reaction. There continues to be interest in the chem- istry of complex tetraazamacrocycles, due to their structural similarity to the active sites of porphyrins and metallopor phyrins, as is the case for tetraaza[14] annulene (TAA) [19]. Oxidation of the binder is favored in TAA systems, compared * Jaldyr de Jesus Gomes Varela, Jr jaldyr.varela@ufma.br 1 Universidade Federal do Maranhão, 65080-805 São Luís, MA, Brazil 2 Universidade Estadual do Maranhão, 65055-970 São Luís, MA, Brazil 3 Instituto de Química de São Carlos, Universidade São Paulo, CP 780, 13560-970 São Carlos, SP, Brazil J Mol Model (2016) 22:217 DOI 10.1007/s00894-016-3097-7