Are all charge-transfer parameters created equally? A study of functional dependence and excited-state charge-transfer quantification across two dye families

Twenty dyes from the Max Weaver Dye Library were used to benchmark six commonly used DFT functionals to understand the interplay between the errors in the calculated excitation energies and the degree of charge transfer character of the excitations.

(Perylene)3-(TCNQF1)2: Yet Another Member in the Series of Perylene–TCNQFx Polymorphic Charge Transfer Crystals

The 3:2 Charge Transfer (CT) co-crystal (Perylene)3(TCNQF1)2 is grown by the Physical Vapor Transport (PVT) method, and characterized structurally and spectroscopically. Infrared analysis of the charge sensitive modes reveals a low degree of charge transfer (less than 0.1) between donor and acceptor molecules. The crystal is isostructural to the other 3:2 CT crystals formed by Perylene with TCNQF2 and TCNQF4, whereas such stoichiometry and packing is not known for the CT crystals with non-fluorinated TCNQ. The analysis of the isostructural family of 3:2 Perylene–TCNQFx (x = 1,2,4) co-crystal put in evidence the role of weak F…HC bonding in stabilizing this type of structure

Crystal structures of two charge–transfer complexes of benzo[1,2-c:3,4-c′:5,6-c′′]trithiophene (D 3h -BTT)

Benzo[1,2-c:3,4-c′:5,6-c′′]trithiophene (D 3h -BTT) is an easily prepared electron donor that readily forms charge–transfer complexes with organic acceptors. We report here two crystal structures of its charge–transfer complexes with 7,7,8,8-tetracyanoquinodimethane (TCNQ) and buckminsterfullerene (C60). The D 3h -BTT·TCNQ complex, C12H6S3·C12H4N4, crystallizes with mixed layers of donors and acceptors, with an estimated degree of charge transfer at 0.09 e. In the D 3h -BTT·C60·toluene complex, C12H6S3·C60·C7H8, the central ring of BTT is `squeezed' by the C60 molecules from both faces. However, the degree of charge transfer is low. The C60 unit is disordered over two sites in a 0.766 (3):0.234 (3) ratio and was refined as a two-component inversion twin.

Tuning of the degree of charge transfer and the electronic properties in organic binary compounds by crystal engineering: a perspective

7,7,8,8-Tetracyanoquinodimethane (TCNQ) and FxTCNQ (x = 1, 2, 4) as acceptors and aromatic hydrocarbons form a variety of compounds in which the degree of charge transfer is tuned by crystal engineering.

Polymorphism controls the degree of charge transfer in a molecularly doped semiconducting polymer

Jacobs et al. present the first observation of both fractional and integer charge transfer phases in a single OSC:dopant system.

An enhanced degree of charge transfer in dye-sensitized solar cells with a ZnO-TiO2/N3/Ag structure as revealed by surface-enhanced Raman scattering

The synergistic effect in ZnO-TiO2/N3/Ag can generate extra enhancements in the SERS intensity and degree of CT.

Lone pair-π interaction-induced generation of photochromic coordination networks with photoswitchable conductance

Lone pair-π interaction-induced variation of the degree of charge-transfer was successfully used for switching the conductance of a photochromic coordination network.

Probing covalency in halogen bonds through donor K-edge X-ray absorption spectroscopy: polyhalides as coordination complexes

The properties of halogen bonds (XBs) in solid-state I2X−and I4X−materials (where X = Cl, Br) are explored using donor K-edge X-ray absorption spectroscopy (XAS) to experimentally determine the degree of charge transfer in such XB interactions. The degree of covalency in these bonds is substantial, even in cases where significantly weaker secondary interactions are observed. These data, in concert with previous work in this area, suggests that certain halogen bonds have covalent contributions to bonding that are similar to, and even exceed, those observed in transition metal coordinate bonds. For this reason, we suggest that XB interactions of this type be denoted in a similar way to coordination bonds (X → Y) as opposed to using a representation that is the same as for significantly less covalent hydrogen bonds (X⋯Y).