DOI: 10.5061/dryad.79cnp5j5j
title: Supplementary data from: Are natural-based isothiocyanate derivatives alternative antioxidant additives used in petrochemical products?

description: Synthetic additives used in petrochemical products, such as plastics,
 rubbers, resins, and polymers, can enter the environment as contaminants
 and pollute the aquatic and soil environment. Thus, using natural-based
 alternative compounds has excellent potential to reduce the negative
 impact. In this study, the role of natural-based isothiocyanate
 derivatives Cp1-Cp4, i.e., allylisothiocyanate,
 1-isothiocyanate-3-methylbutane, 4-methylphenyl isothiocyanate, and
 2-phenylethyl isothiocyanate in use as primary antioxidant additives was
 studied via their HOꞏ-radical scavenging activity. Formal hydrogen
 transfer, radical adduct formation, and single electron transfer
 mechanisms were investigated in water and pentyl ethanoate (PEA) using
 Density Functional Theory at
 M06-2X/6-311++G(3df,3pd)//M06-2X/6-311++G(d,p) level of theory. The
 results illustrated the high HOꞏ-scavenging activity of the isothiocyanate
 compounds with rate constants of about 108 - 109 M-1s-1.
 Allylisothiocyanate Cp1 represents the most efficient HOꞏ-scavenger with
 koverallof5.20 × 109 M-1s-1 in water and 1.85 × 109 M-1s-1 in PEA. These
 results allow us to enrich the data on effective antioxidant additives
 from natural sources to reduce HOꞏ-radicals-induced oxidation processes in
 different environmental conditions.
description: All DFT calculations were performed by Gaussian 16 Rev. C.01
 package. The Gaussian Post Processor (GPOP) program was used to calculate
 the rate constant for chemical reactions. 
description: # Supplementary data from: Are natural-based isothiocyanate derivatives
 alternative antioxidant additives used in petrochemical products? ####
  Description of the data and file structure  The electronic supplementary
 information (ESI) within our submission contains underlying data that was
 generated and used to support the conclusions presented in our study. This
 data is compatible with the CC0 waiver required by Dryad for publication
 and is not included in our related manuscript. The ESI file presents a
 detailed explanation of the computational method used in the main
 manuscript. The ESI data show additional results for formal hydrogen
 transfer (FHT) (Table S1 to S3) and radical adduct formation (RAF) (Table
 S4 to S6) reactions between the studied isothiocyanates and HO• radicals.
 **File: ESI_TCNgo.docx** **List of Tables in the ESI file** Table S1 shows
 relative reaction enthalpies at 0 K (∆r*H*0K) for reactant complex (RC),
 transition states (TS), product complexes (PC), and product (P) of FHT
 reactions between the studied isothiocyanates and HO• radical in water and
 pentyl ethanoate (PEA) using the
 M06-2X/6-311++G(3df,3pd)//M06-2X/6-311++G(d,p) level of theory. All
 energies are in kcal mol-1. Table S2 displays optimized structures, and
 Cartesian coordinates of all reactant complexes (RC), transition states
 (TS), product complexes (PC), and products (P) for FHT reactions between
 the studied isothiocyanates and HO• in water and pentyl ethanoate (PEA) at
 the M06-2X/6-311++G(d,p) level of theory. Table S3 shows thermal rate
 constant (*k*T, M-1s-1) and diffusion rate constant (*k*D, M-1s-1)
 calculated at 298 K for FHT reactions at each C−H between the studied
 isothiocyanates and HO• radical in water and pentyl ethanoate (PEA) using
 the M06-2X/6-311++G(3df,3pd)//M06-2X/6-311++G(d,p) level of theory. Table
 S4 shows relative reaction enthalpies at 0 K (∆r*H*0K) for reactant
 complex (RC), transition states (TS), and product (P) of RAF reactions
 between the studied isothiocyanates and HO• radical in water and pentyl
 ethanoate (PEA) using the M06-2X/6-311++G(3df,3pd)//M06-2X/6-311++G(d,p)
 level of theory. All energies are in kcal mol-1. Table S5 displays
 Optimized structures, and Cartesian coordinates of all reactant complexes
 (RC), transition states (TS), and products (P) for RAF reactions between
 the studied isothiocyanates and HO• in water and pentyl ethanoate (PEA) at
 the M06-2X/6-311++G(d,p) level of theory. Table S6 shows thermal rate
 constant (*k*T, M-1s-1) and diffusion rate constant (*k*D, M-1s-1)
 calculated at 298 K for RAF reactions between the studied isothiocyanates
 and HO• radical in water and pentyl ethanoate (PEA) using the
 M06-2X/6-311++G(3df,3pd)//M06-2X/6-311++G(d,p) level of theory.
 **Code/Software** All DFT calculations are performed with the Gaussian 16
 Rev.C.01 package (*[https://gaussian.com/)](https://gaussian.com/).* The
 Gaussian Post Processor (GPOP) program is employed to calculate the rate
 constants of the studied reactions
 (*[http://akrmys.com/gpop/](http://akrmys.com/gpop/)*).