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Electronic Excitation of [(μ4-η2-alkyne)Rh4(CO)8(μ-CO)2]: An In Situ UV/Vis Spectroscopy, Spectral Reconstruction and DFT StudyDr. Feng Gao, Dr. Michael B. Sullivan, Prof. Gulnara M. Kuramshina, Dr. Liangfeng Guo, Dr. Marc GarlandInstitute of Chemical and Engineering Sciences, A*STAR (Agency for Science Technology and Research), 1 Pesek Road, Jurong Island, Singapore, 627833 (Singapore) Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 1386321 (Singapore) Department of Physical Chemistry, Faculty of Chemistry, Moscow State University, Moscow 119991 (Russia) Article first published online: 15 JUN 2012 ChemPhysChem 2012, 13, 3139-3145. ABSTRACT: Reactions of three alkynes, namely, 1-heptyne, 3-hexyne and 1-phenyl-1-butyne, with [Rh4(CO)9(μ-CO)3] are performed in anhydrous hexane under argon atmosphere with multiple perturbations of alkynes and [Rh4(CO)9(μ-CO)3]. The reactions are monitored by in situ UV/Vis spectroscopy, and the collected electronic spectra are further analyzed with the band-target entropy minimization (BTEM) family of algorithms to reconstruct the pure component spectra. Three BTEM estimates of [(μ4-η2-alkyne)Rh4(CO)8(μ-CO)2], in addition to that of [Rh4(CO)9(μ-CO)3], are successfully reconstructed from the experimental spectra. Time-dependent density functional theory (TD-DFT) predicted spectra at the PBE0/DGDZVP level are consistent with the corresponding BTEM estimates. The present study demonstrates that: 1) the BTEM family of algorithms is successful in analyzing multi-component UV/Vis spectra and results in good spectral estimates of the trace organometallics present; and 2) the subsequent DFT/TD-DFT methods provide an interpretation of the nature of the electronic excitation and can be used to predict the electronic spectra of similar transition organometallic complexes. | |||||||