Why Bindschedler’s Green Is Redder Than Michler’s Hydrol Blue

Abstract

We offer a new physical interpretation of the color shift between diarylmethane dyes and their azomethine analogues. We use an isolobal analogy between state-averaged complete active space self-consistent field solutions for corresponding methines and azomethines to show that the shift contains a significant contribution from configuration interaction between a methine-like ππ* excitation and an nπ* excitation out of the azomethine lone pair. The latter does not exist in the corresponding methine systems. This picture is qualitatively inconsistent with traditional models of the shift based on molecular orbital perturbation theory of independent π-electron Hamiltonians. A key prediction is the existence of a dipole-allowed band in the blue/near-UV spectra of the azomethines, which has polarization parallel to the lowest energy band. This forces a revision of past assumptions about the nature of the low-energy spectra of the azomethines. A band at the predicted energies has been observed in solution-state spectra.

Biscarbazolylmethane-based cyanine: a two-photon excited fluorescent probe for DNA and selective cell imaging

“…Firstly, the non-conjugated structure will keep the photophysical properties of monocyanine, voiding the hyperchromism in UV and bathochromism in uorescence, resulting in the large Stokes shi. Secondly, the intramolecular charge transfer through the methylene group ("through-space" type) may exist in excited state of the molecule, 35,36 which could dedicate to large TPA cross section. Thirdly, the non-rigid connected bis-cationic centres in the molecule would make it easier to adjust the distance of two cationic centres and the molecular orientation compared with the rigid-connection one in biscyanine, which will cause the strong interaction with DNA.…”

The Chromogen, Structure, Inspirations, and Applications of a Photo-, pH-, thermal-, Solvent-, and Mechanical-Response Epoxy Resin

“…When one of three benzene rings is removed, the rest (diarylmethane 34 ) shares a similar structure in common with MC-1. Search results show that the structure in Figure 8 is a known substanceMichler's hydrol blue, 35,36 which shares the same color with the solution of MC-1. Michler's hydrol blue is one kind of artificial colors (diarylmethane dye).…”

Canonical-ensemble state-averaged complete active space self-consistent field (SA-CASSCF) strategy for problems with more diabatic than adiabatic states: Charge-bond resonance in monomethine cyanines

“…The two-state solution for HB has been described in previous work. 60,61 The converged active spaces were visually indistinguishable from Fig. 1 at all "temperatures."…”

“…The ground state geometry has been discussed previously. 34,[60][61][62] The weights were determined self-consistently as a canonical distribution over the six-dimensional Hilbert space of configurations of active electrons. Equilibration of the SA-CASSCF weights was implemented using an iterative loop in 's internal scripting language, wherein the a priori weights of each SA-CASSCF calculation were calculated using state energies from the previous calculation, and the process was iterated to convergence.…”