Electronic and Steric Effects on L-Lactide Ring-Opening Polymerization with NSSN-type Zr(IV) Complexes |
| |
| Authors: | Dr Ida Ritacco Dr Maria Voccia Dr Salvatore Impemba Dr Matteo Farnesi Camellone Prof Stefano Milione Prof Lucia Caporaso |
| |
| Institution: | 1. DCB, Department of Chemistry, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Salerno, Italy;2. CNR-ITAE, Consiglio Nazionale delle Ricerche, Istituto di Tecnologie Avanzate per l'Energia “Nicola Giordano”, Salita Santa Lucia Sopra Contesse 5, 98126 Messina, Italy;3. CNR-ICCOM, Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organometallici, 50019 Firenze, Italy;4. CNR-IOM Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, Edificio Q2 Area Science Park Strada Statale 14, 34149 Basovizza, Trieste, Italy |
| |
| Abstract: | In this work the mechanism of L-lactide polymerization promoted by NSSN zirconium complexes was investigated through DFT methods with the aim to understand as the electronic and steric features of the ligand affect the energy reaction. It was observed that the rate determining step of the process is the opening of the L-lactide ring and that by increasing the steric hindrance, evaluated by changing geometric parameters and topographic steric maps, or the electron-withdrawing properties of the ligand, the corresponding energy barrier increases. On the other hand, calculations foresee that a small and electron-releasing substituent on the nitrogen atom of the ligand, such as the methyl group, is desirable in order to obtain NSSN zirconium based catalysts with improved activity in the ROP of the L-lactide. |
| |
| Keywords: | Density functional calculations L-lactide ring-opening polymerization zirconium catalysis |
|
|
