Preparation, Characterization, Molecular and Electronic Structures, TDDFT, and TDDFT/PCM Study of the Solvatochromism in Cyanovinylferrocenes

Abstract

Cis and trans isomers of ferrocene-based donor-acceptor assemblies, Fc-C(I)=CH(I), Fc-C(I)=CH(CN), and Fc-C(CN)=CH(CN) (Fc is ferrocene), along with the Fc-C(CN)=C(CN)2 complex have been prepared and characterized by 1H, 13C, gHMQC, and gHMBC NMR spectra, IR, UV-vis, and MCD spectroscopy methods, as well as elemental analyses. The oxidation potentials, investigated by cyclic voltammetry, of all donor-acceptor assemblies are in agreement with the electron-acceptor strength of the substituents attached to the ferrocene core. X-ray crystallography studies of cis and trans isomers of Fc-C(I)=CH(CN) and Fc-C(CN)=CH(CN) reveal a significant rotational flexibility of the cyanovinyl group, which was explained on the basis of semiempirical PM3 calculations. Electronic structures and solvatochromic properties of all complexes were investigated by UV-vis spectroscopy, density functional theory (DFT), time-dependent DFT (TDDFT), and polarized continuum model (PCM) TDDFT approaches. The calculated vertical excitation energies and magnitudes of solvatochromic effect are consistent with the experimental data and clearly suggest the dominance of metal-to-ligand charge-transfer bands in the visible region of the UV-vis spectra for all complexes.

Density functional theory studies on the structures and electronic communication of meso-ferrocenylporphyrins: Long range orbital coupling via porphyrin core

“…This, however, has not yet been confirmed from the point of theoretical investigation because of the lack of theoretical calculations in this regard. On the other hand, density functional theory (DFT) and time dependant density functional theory (TD-DFT) methods have proved suitable for the calculation of the energy-minimized structures, electronic distribution, molecular orbitals, electron transfer, and electronic absorption spectra of a series of porphyrin and phthalocyanine derivatives [17][18][19][20][21][22][23] as well as ferrocene derivatives [24][25][26][27][28][29]. As a consequence, towards understanding the long range electronic coupling between ferrocenyl groups connected via porphyrin framework, theoretical studies over multi-component compounds composed of porphyrin and ferrocenyl units appear interesting.…”

Metal atom dynamics in organometallics: Cyano ferrocenes

“…Compound 4 [2] as well as compounds 2, 3, 5, and 6 [8] were prepared using literature methods. (b) Mö ssbauer spectroscopy (MES): The air stable solids were ground with Pyrex powder and mixed with BN to ensure random crystallite orientation in the subsequent MES measurements, transferred to Perspex sample holders, and mounted in a cryostat in transmission geometry as previously described [3][4][5][6].…”

“…(c) All DFT calculations were conducted using the GAUSSIAN 03 software package [10] running under either Windows or UNIX OS. In the present investigation, we have used X-ray determined geometries [2,8]. In the case of single point calculations, for all compounds, Becke's pure exchange functional [11] and Perdew and Wang's correlation functional [12] (BPW91) was used.…”

Synthesis and Properties of Mononuclear Group 10 Alkoxy‐Biscarbene Complexes

“…[14,18] To corroborate this fact, UV/Vis spectra of representative complexes 15 and 16 were registered in solvents of different polarity. The data in Table 1 show that the LF band of complexes 15 a and 16 a is practically independent of the polarity of the solvent, which confirms the p-p* nature of this absorption.…”

“…[14,18] Electrochemistry 6 ) as the supporting electrolyte). Oxidation and reduction potentials were measured using an Ag/ AgNO 3 reference electrode, a glassy carbon-working electrode, and a platinum counter electrode.…”