Intercage Electron Transfer Driven by Electric Field in Robin–Day‐Type Molecules

Abstract

A new class of isomers, namely, intercage electron-transfer isomers, is reported for fluorinated double-cage molecular anion e(-)@C(20)F(18)(NH)(2)C(20)F(18) with C(20)F(18) cages: 1 with the excess electron inside the left cage, 2 with the excess electron inside both cages, and 3 with the excess electron inside the right cage. Interestingly, the C(20)F(18) cages may be considered as two redox sites existing in a rare nonmetal mixed-valent (0 and -1) molecular anion. The three isomers with two redox sites may be the founding members of a new class of mixed-valent compounds, namely, nonmetal Robin-Day Class II with localized redox centers for 1 and 3, and Class III with delocalized redox centers for 2. Two intercage electron-transfers pathways involving transfer of one or half an excess electron from one cage to the other are found: 1) Manipulating the external electric field (-0.001 a.u. for 1→3 and -0.0005 a.u. for 1→2) and 2) Exciting the transition from ground to first excited state and subsequent radiationless transition from the excited state to another ground state for 1 and 3. For the exhibited microscopic electron-transfer process 1→3, 2 may be the transition state, and the electron-transfer barrier of 6.021 kcal mol(-1) is close to the electric field work of 8.04 kcal mol(-1).

The Importance of Being Inconsistent

“…The delocalization error has been implicated in difficulties calculating alkylcobalamins [GNPM13], where HF-DFT might be very helpful. It has also been useful in analyzing intercage electron transfer in Robin-Day type molecules [WLZL12], and a large density-driven error has been found in the Kevan model of a solvated electron [JOD13]. IR spectra of small anionic water clusters have been shown to be problematic with fixed basis DFT calculations, and fixed by MP2 [GDTJ15].…”

Bioinspired approach toward molecular electrets: synthetic proteome for materials

“…As a result, local electric fields from molecular dipoles and ions affect ET [94][95][96][97][98][99], providing a promising means for increasing the efficiency of the desired CT processes while suppressing the undesired ones. Small dipolar moieties modify the electron affinity and the ionization energy of materials [100][101][102][103][104].…”

Molecular Spin Switch and Conversions of Localized Excess Electrons under External Electric Field: Solvated Dielectron C20F20@K@C20F20@K@C20F20

“…To improve stabilities of general solvated electrons, in our recent series of papers, [24][25][26][27][28][29] basing on the synthesized C 20 F 20 and potential C 24 F 24 and C 60 F 60 cage, 30,31 we have constructed a series of interesting cage-like single molecular solvated (di)electron systems with large stabilities due to the using covalent cages: e@C 60 F 60 , e 2 @C n F n (n=20, 28, 36, 50, 60, and 80), e@C 20 F 18 (NH) 2 C 20 F 18 , and e@C 24 F 22 (NH) 2 C 20 F 18 , which shows these perfluorinated cages are efficient containers of excess electrons. For these cages, the dipole moments of all the exo polarized C δ+ -F δ-bonds of each cage are directed toward the center of the cage to form an interior electronic attractive potential (IEAP) which can help to trap excess electron(s) inside these cages.…”

“…Also, basing on triple-cage-like electride salt K + [e@3C 8 (O)] -, Li et al, also suggested 33 that multicage strategy is effective to enhance nonlinear optical (NLO) response. For the double-cage-like single molecular solvated single electron systems e -@C 20 F 18 (NH) 2 C 20 F 18 , [26][27][28] the excess electron can be trapped inside different cages to form interesting inter-cage electron transfer isomers. 26 In this case, besides the double-cage-like single molecular solvated electron systems, 20,21,[26][27][28] We are interesting in the influence of the number of cage units on the localizations and spin states of two excess electrons.…”

“…34 Straka et al demonstrated for MX@C 70 (M: metal, X: nonmetal) systems that the relative orientation of enclosed MX with respect to a set of electrodes connected to the system can be controlled by application of OEEF(s). 2 For the double-cagelike single molecular solvated electron systems of e@C 20 F 18 (NH) 2 C 20 F 18 , and e@C 24 F 22 (NH) 2 C 20 F 18 , [26][27] we have also used an external electric field to realize the inter-cage excess electron transfer and isomerization among three inter-cage electron transfer isomers. These will provide an approach for the manipulating localization(s) and spin states of the excess electron(s) in multi-cage-shaped solvated dielectron systems by using external electric field.…”