Design and Theoretical Study of D–A–π–A Organic Sensitizers with [1,2,5]Thiadiazolo[3,4-c]pyridine, [1,2,5]Selenadiazolo[3,4-c]pyridine, and [1,2,5]Oxadiazolo[3,4-c]pyridine π Component

Abstract EN

The study concerns molecular design and theoretical study of novel prospective organic sensitizers based on D–A–π–A concept.

A modification of the concept (DA–π–A) and new ways for design of organic sensitizers are proposed.

The study shows that π-block plays a key role for the wavelength shift in UV-Vis spectra.

An existence of element of higher periods in the π-block provides a noticeable bathochromic shift.

The thienyl bridge in A-block provides a red shift with respect to phenyl bridge for [ 1,2,5 ] oxadiazolo [ 3,4-c ] pyridines while the phenyl bridge provides a red shift with respect to thienyl bridge for [ 1,2,5 ] selenadiazolo [ 3,4-c ] pyridines.

The maximal wavelengths are observed for DA-blocks with aliphatic/alicyclic fragments we proposed.

An influence of enthalpy of formation and polarity of DA-blocks on bathochromic shift is shown.

The quantitative dependencies of wavelengths on the enthalpies and dipole moments are determined.

The maximal oscillator strengths are observed for the planar DA-block.

Therefore, the conditions for design of compounds possessing the maximal wavelengths and oscillator strengths are different: the latter presupposes the planar structure of DA-block while the first presupposes an existence of nonplanar aliphatic/alicyclic fragments.

Thus, the further design of organic sensitizers should include some combination of these concepts.