(710e) Investigation of the Reaction of Rh2(CO)4Cl2 with Two Dienes by in-Situ Vibrational Spectroscopies, Spectral Reconstruction and DFT Study

Reactions of Rh2(CO)4Cl2 with 1,5-cyclooctadiene (COD) [1] and 2,3-dimethyl-1,3-butadiene (DBD) were performed separately in anhydrous hexane under argon atmosphere. Multiple perturbations of Rh2(CO)4Cl2, COD and DBD were also performed during the reactions. These two reactions were monitored by in-situ FTIR (FIR and MIR) and/or Raman spectroscopies and the collected spectra were further analyzed with BTEM family of algorithms [2]. DFT calculations [3] were performed to confirm the organometallic species present. The known diene complexes Rh2(CO)2Cl2(eta4-C8H12) and Rh2(CO)4Cl2(eta4-C8H14) were formed as two primary organo-rhodium products respectively. Their pure component spectra were reconstructed in the three characteristic FTIR regions of 200-680, 800-1360, and 1500-2200 cm-1. Their relative concentrations were also obtained by the least square fitting of the carbonyl region 1500-2200 cm-1. In addition, the FTIR-Raman BTEM estimate of Rh2(CO)4Cl2(eta4-C8H14) was obtained in the region of 1900-2150 cm-1. The present contribution shows the usefulness of combining in-situ spectroscopic measurements, BTEM analysis and DFT spectral prediction in order to analyze the organometallic reactions at high dilution and identify the reaction products.