Synthesis and Photochromism of Novel Pyridyl-Substituted Naphthopyrans

Abstract

Multi-target synthetic strategies to access novel photochromic 3H-naphtho[2,1b]pyrans decorated with pyridyl units are described. The new pyridyl substituted 3Hnaphtho[2,1-b]pyrans display good photochromic properties with the reversible generation of photomerocyanines which exhibit mainly orange/red hues. Photochromic parameters including photocolourability and persistence of colour vary tremendously on structural modification of the naphthopyran core.

Blockade of persistent colored isomer formation in photochromic 3H-naphthopyrans by excited-state intramolecular proton transfer

“…S1 ), likely due to disruption of the internal hydrogen bond in TC by solute–solvent specific interactions. Such an equilibrium between TC and CF has been reported for a similar NP derivative 52 . To explore this phenomenon, various TC and methanol (1:1) complexes were calculated (Fig.…”

2,2,4,6-Tetraaryl-2H-benzo[h]chromenes: The influence of electronic communication between aryl substituents on their photochromism

“…The alternative route, Route B, relies upon an initial Suzuki cross-coupling to 4-bromo-1naphthol to afford the 4-aryl-1-naphthols 14 which can then undergo chromenization with a 1,1,3-triarylprop-2yn-1-ol 12 to afford 9 (Scheme 1). Given our experience concerning the synthesis of triaryl substituted 2H-benzo[h]chromenes [27,28] and Suzuki cross-couplings to bromo substituted benzochromenes [29][30][31][32] we elected to initially examine Route A with the late-stage Suzuki cross-coupling reaction.…”

Photochromic spiro-indoline naphthoxazines and naphthopyrans in dye-sensitized solar cells

“…First, naphthalene-1,3-diol was methylated in position 3 prior to introduce the triflate group in position 1. 29 The carbonyl group was then introduced in position 4 through a Rieche formylation and eventually the alcohol was deprotected in the presence of boron tribromide to obtain the naphthol 5. On the other hand, to prepare the donating block 6, the Fischer's base was first brominated according to previously reported conditions 30 and then the diphenylamine moiety was introduced through a Buchwald-Hartwig amination.…”