43134-09-4Relevant articles and documents
Squarilium Dyes, their Infrared and Resonance Raman Spectra and Possible Use in Redox Reactions for Solae-energy Conversion
Forster, Martin,Hester, Ronald E.
, p. 1847 - 1866 (1982)
Infrared and resonance Raman spectra of squarilium dyes I-VI of the type are presented and some vibrational modes of the central 4-membered ring are assignated.Methyl viologen dication (MV(2+)) is reduced photocatalytically by IV in DMSO+H2O (95/5, v/v) with a quantum yield φ of (1.8+/-0.4)E-3 at 406.7 nm, if EDTA is present.Oxidation products of MV(2+) behave similarly with φ = (4.7+/-0.6)E-2 at 457.9 nm in DMF+H2O (2/1, v/v).IV(1+). seems to oxidize H2O nearly reversibly.
Isomeric squaraine-based [2]pseudorotaxanes and [2]rotaxanes: Synthesis, optical properties, and their tubular structures in the solid state
Xue, Min,Su, Yong-Sheng,Chen, Chuan-Feng
experimental part, p. 8537 - 8544 (2010/10/01)
On the basis of formation of [2]pseudorotaxane complexes between triptycene-derived tetralactam macrocycles la and lb and squaraine dyes, construction of squaraine-based [2]rotaxanes through clipping reactions were studied in detail. As a result, when two symmetrical squaraines 2d and 2e were utilized as templates, two pairs of isomeric [2]rotaxanes 3a-b and 4a-b as diastereomers were obtained, owing to the two possible linking modes of triptycene derivatives. It was also found, interestingly, that when a nonsymmetrical dye 2 g was involved, there existed simultaneously three isomers of [2]rotaxanes in one reaction due to the different directions of the guest threading. The 1H NMR and 2D NOESY NMR spectra were used to distinguish the isomers, and the yield of [2]rotaxane 5 a with the benzyl group in the wider rim of the host la was found to be higher than that of another isomer 5 b with an opposite direction of the guest, which indicated the partial selection of the threading direction. The X-ray structures of 3 b and 4 a showed that, except for the standard hydrogen bonds between the amide protons of the hosts and the carbonyl oxygen atoms of the guests, multiple Ji-Ji stacking and C-H-ji interactions between triptycene subunits and aromatic rings of the guests also participated in the complexation. Crystallographic studies also revealed that the [2]rotaxane molecules 3 b and 4 a further self-assembled into tubular structures in the solid state with the squaraine dyes inside the channels. In the case of 4 a, all the nonsymmetrical macrocyclic molecules pointed in one direction, which suggests the formation of oriented tubular structures. Moreover, it was also found that the squaraines encapsulated in the triptycenederived macrocycles were protected from chemical attack, and subsequently have potential applications in imaging probes and other biomedical areas.
Squaraine chemistry. Synthesis of bis(4-dimethylaminophenyl)squaraine from dialkyl squarates. Mechanism and scope of the synthesis
Law, Kock-Yee,Bailey, F. Court
, p. 2267 - 2273 (2007/10/02)
The mechanism and the scope of the synthesis of bis(4-dialkylaminoaryl)squaraines from di-n-butyl squarate and N,N-dialkylanilines have been studied.Results show that water and acid are key factors of the synthesis, and these two factors have been optimized.Yields of squaraine are also found to be sensitive to the steric effect provided by the alkyl chain in dialkyl squarates as well as to the concentration of the aniline reagent used in the synthesis.Mechanistic results suggest that alkyl squarate is the precursor of the synthesis, and that squaraine is formed by diarylation of alkyl squarate with and N,N-dialkylaniline derivative.Under optimized conditions, a number of squaraines have been synthesized.Yields, which are comparable to those synthesized from squaric acid, are obtained.Product analysis with good material balance has been achieved, and results show that arylation and diarylation of the starting di-n-butyl squarate are major side reactions in the squaraine synthesis.
