Abstract

Agus Abhi Purwoko and Saprizal Hadisaputra

DOI : http://dx.doi.org/10.13005/ojc/330218

Synthesis of arenetricarbonylchromium(0) complexes, [(η⁶-arene)Cr(CO)₃], has been carried out, wherein arene were benzene (Ph), chlorobenzene (PhCl), phenyltrimethylsilane (PhSiMe₃), and acenaphthene (PhNp). Characterization of the compounds was carried out using NMR, IR and UV-visible spectrophotometers. Electronic absorption of these complexeswere measured in various solvents namely methanol, methylene chloride, chloroform, benzene, and isooctane. The complexes showed the electronic absorption of the lowest in the energy range of 313-320 nm, with a relatively high intensity. Density functional theory at the B3LYP/LanL2DZ level of theory was also used to study the geometry parameters, binding energy (BE), vibrational spectra, electronic spectra, frontier molecular orbital (NBO analysis), charge transfer (CT) of the complexes. It was found that the order of the complex stability is: (PhSiMe₃)Cr(CO)₃> (Ph)Cr(CO)₃> (PhNp)Cr(CO)₃> (PhCl)Cr(CO)₃. The NBO analysis showed that the stability of the complexes arising fromintramolecular interactions and electron delocalization in which synergistic interaction occurs in the arenehyperconjugative orbital ring for metal antibonding orbital and back donation (via metal bonding orbital to bond antibonding orbital ring). The electronic spectrum shows the charge transfer is dominated by ligand to metal charge transfer (LMCT) transition, except for (PhNpe)Cr(CO)₃that is dominated by metal to ligand charge transfer (MLCT) and only a small portion is set to d-d transition.

Arenetricarbonylchromium; charge transfer transition; DFT; TD-DFT; NBO

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