The reactions of Rh2(CO)4Cl2 with 1,5-cyclooctadiene and tetramethylallene. A combined in-situ vibrational spectroscopies, spectral reconstruction and DFT study

Reactions of Rh-2(CO)(4)Cl-2 with 1,5-cyclooctadiene (COD) and tetramethylallene (TMA) were performed separately in anhydrous hexane under argon atmosphere. Multiple perturbations of Rh-2(CO)(4)Cl-2, COD and TMA 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. DFT calculations were performed to identify the organometallic species present. The known diene complex Rh-2(CO)(2)Cl-2(eta(4)-C8H12) and a new allene complex Rh-2(CO)(3)Cl-2(eta(2)-C7H12) were formed as the two primary organo-rhodium products. Their pure component spectra were reconstructed in the three characteristic 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). The present contribution shows the usefulness of combining in-situ spectroscopic measurements, BTEM analysis and DFT spectral prediction in order to analyze organometallic reactions at high dilution and identify the reaction products. (C) 2010 Elsevier B.V. All rights reserved.