105810-36-4Relevant academic research and scientific papers
Thermotropic behaviour, self-assembly and photophysical properties of a series of squaraines
Qaddoura, Maher A.,Belfield, Kevin D.,Tongwa, Paul,Desanto, Jessica E.,Timofeeva, Tatiana V.,Heiney, Paul A.
, p. 731 - 742 (2011)
A series of squaraine dyes, based on 2,4-bis[4-(N,N-di-n-alkylamino)-2- hydroxyphenyl] squaraine including ethyl, propyl, butyl, pentyl, hexyl and heptyl derivatives, were synthesised by condensation of the corresponding 4-(N,N-di-n-alkylamino)-2-hydroxyp
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. On the anomalous mass spectra of bis(4-dimethylaminophenyl)squaraine and its derivatives
Law, Kock-Yee,Bailey, F. Court,Bluett, Lynn J.
, p. 1607 - 1619 (2007/10/02)
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.
