Biocompatible organic charge transfer complex nanoparticles based on a semi-crystalline cellulose template

Abstract

Using a bio-inspired cellulose template, new charge transfer (CT) nanoparticles (NPs) with unique and intriguing emission properties are reported. Pyrene-modified 2,3-di-O-methyl cellulose formed CT complexes with small molecule acceptors, e.g. 7,7,8,8-tetracyanoquinodimethane (TCNQ), and exhibited aggregation-induced emission (AIE) in aqueous medium upon nanoparticle formation. The TCNQ-CT NPs showed multicolor fluorescence emissions at 370-400 nm, 602 nm and 777 nm, when excited at 330 nm, 485 nm and 620 nm respectively. The cellulose-TCNQ NPs are biocompatible and demonstrate an advance in the use of the CT mechanism for biomedical imaging applications both in vitro and in vivo.

Triggering Gel Formation and Luminescence through Donor–Acceptor Interactions in a C3‐Symmetric Tris(pyrene) System

“…Moreover, the choice of the excitation wavelength is critical, as for λ exc =405 (Figure S7 in the Supporting Information), 480 and 788 nm, the two latter corresponding to the charge‐transfer absorption bands, no significant emission was observed. It has been recently shown that the fluorescence of charge transfer complexes of pyrene based materials with TCNQ is highly dependent on the excitation wavelength and the solvent …”

“…It has been recently shown that the fluorescenceo fc harget ransfer complexes of pyrene based materials with TCNQ is highly dependent on the excitationwavelength andt he solvent. [24] In summary we have synthesized af irst C 3 -symmetric system based on the tris(3,3'-diamido-2,2'-bipyridine)-benzene-1,3,5-tricarboxamide core and pyrene units as an ew luminescent electroactiveo rganogelator.R emarkably,i ts gelation capacity in 1,1,2,2-tetrachloroethane increases by an ordero fm agnitude upon addition of TCNQ throught he establishment of intermolecular donor-acceptor interactions. The latter play very likely ad etermining role in the formationm echanism of the gel.…”

Tuning the Organogelating and Spectroscopic Properties of a C3‐Symmetric Pyrene‐Based Gelator through Charge Transfer

“…Tris(3,3’‐diamido‐2,2’‐bipyridine)‐benzene‐1,3,5‐tricarboxamide‐based C 3 compounds exhibit a strong propensity to form highly ordered nanostructures through combined intramolecular H‐bonds and intermolecular π–π interactions [58–64] . On the other hand, pyrene is known to interact with electron‐poor molecules such as TNF [47–50] and TCNQ [68, 69] . The C 3 Pyr system, bearing three attached donating (D) pyrene groups surrounding the C 3 platform, behaves as an electron‐rich supramolecular building block.…”

“…Infrared (IR) absorption spectroscopy has been widely used to estimate the degree of charge transfer (DCT) in D‐A complexes involving the TCNQ unit [75, 76, 68] . A correlation can be drawn between the vibration frequency of its cyano (CN) groups and the DCT, limit reference compounds being neutral TCNQ ( ρ =0 e − /molecule) and the salt TCNQ‐K ( ρ =1 e − /molecule).…”

Charge‐Transfer‐Complexed Conjugated Microporous Polymers (CT‐CMPs)

“…To overcome this, we chemically bonded the CT complexes to a semicrystalline cellulose template following previous work on the use of CT complexes for medical imaging. [ 13 ] The modular structure of CT complexes, along with the dependence of their properties on spatial and environmental factors, allows control over the crystal structure and optical properties by alternating the CT interaction between electron donors and electron acceptors. However, elucidating the necessary parameters for efficient CT complexation of polymers with small molecules remains challenging.…”