13458-60-1

Upstream product

• 61732-53-4 di-n-propyl squarate 
• 121-69-7 N,N-dimethyl-aniline 
• 2892-62-8 3,4-dibutoxy-3-cyclobutene-1,2-dione 
• 107885-39-2 3-(4-(N,N-dimethylamino)phenyl)-4-hydroxycyclobut-3-ene-1,2-dione 
• 43134-09-4 bis[4-(dimethylamino)phenyl]squaraine 
• 2892-51-5 squaric acid 

Relevant academic research and scientific papers

Generation and Spectroscopic Characterization of Two Persistent Radical Cations from Bissquaraine

The squarine dye bissquaraine gives a persistent radical cation upon one-electron oxidation in dichloromethane.In the presence of trifluoroacetic acid in high concentration (0.5-1.0 M), a second persistent radical cation is detectable upon oxidation, most likely formed by one-electron loss from a dye species protonated on one oxygen and one nitrogen.Both species were characterized by their UV-vis and EPR spectral properties.

Chromogenic detection of hydrogen sulfide using squarylium-based chemosensors

Squarylium-based colorimetric hydrogen sulfide (H2S) chemosensors (SQ1, SQ2, and SQ3) were developed, and their detection properties were systematically characterized. SQ1 exhibited rapid and high resolution H2S sensing properties th

Isomeric squaraine-based [2]pseudorotaxanes and [2]rotaxanes: Synthesis, optical properties, and their tubular structures in the solid state

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. A new approach to symmetrical and unsymmetrical photoconductive squaraines. Characterization and solid state properties of these materials

A new approach to 1-(p-dimethylaminophenyl)-2-hydroxycyclobutene-3,4-dione (4), a precursor for the synthesis of symmetrical and unsymmetrical photoconductive squaraines, is described.In situ generation of p-nitrophenyl ketene, by the reaction of p-nitrop

Squaraine chemistry. Synthesis of bis(4-dimethylaminophenyl)squaraine from dialkyl squarates. Mechanism and scope of the synthesis

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.

Squaraine chemistry. On the anomalous mass spectra of bis(4-dimethylaminophenyl)squaraine and its derivatives

The electron inpact (EI) mass spectra of bis(4-dimethylaminophenyl)squaraine 1 and its derivatives 2-14 have been studied.Ions of mass number higher than the molecular ion, wich are shown to be precursors of fragment ions of lower mass numbers, are observed.From the structure-property relationship, these ions are assigned to M + CHR and M + H2 , were CH2R is the alkyl group in the N,N-dialkylanilino moiety of squaraine.Evidence is provided that the formation of M + CHR and M + H2 is the result of alkyl transfer and H transfer reactions within a squaraine aggregate rather than intermolecular vapor phase reeactions in the massspectrometer.This molecular aggregate is later shown to be a trimer by analysis of metastable ion data and chemical ionization mass spectrometry.The fragmentation sequence of this trimeric species is elucidated with the assistance of metastable ions.Results show that the trimer may break down to monomeric and dimeric species upon electron impact; alternatively,the four-membered ring of the central squaraine in the trimer may cleave to generate two species of approximately equal mass number.These two species usually dominate the mass spectrum and further fragment into M + CHR and M + H2.Detailed fragmentation schemes for M + CHR and M + H2 are proposed and discussed.