30 Apr 10:58
by Zhiqian Guo,
Chenxu Yan,
Wei‐Hong Zhu
In this Minireview , recent advances related to the aggregation‐induced emission (AIE) building block quinoline‐malononitrile are summarized. It focuses on the AIE mechanism, regulation of emission wavelength and morphology, the facile scale‐up and fast preparation for AIE nanoparticles, and potential biomedical imaging applications.
Abstract
In vivo fluorescent monitoring of physiological processes with high‐fidelity is essential in disease diagnosis and biological research, but faces extreme challenges due to aggregation‐caused quenching (ACQ) and short‐wavelength fluorescence. The development of high‐performance and long‐wavelength aggregation‐induced emission (AIE) fluorophores is in high demand for precise optical bioimaging. The chromophore quinoline‐malononitrile (QM) has recently emerged as a new class of AIE building block that possesses several notable features, such as red to near‐infrared (NIR) emission, high brightness, marked photostability, and good biocompatibility. In this minireview, we summarize some recent advances of our established AIE building block of QM, focusing on the AIE mechanism, regulation of emission wavelength and morphology, the facile scale‐up and fast preparation for AIE nanoparticles, as well as potential biomedical imaging applications.
21 Jun 00:45
by Eike Dornsiepen,
Florian Dobener,
Nils Mengel,
Olena Lenchuk,
Christof Dues,
Simone Sanna,
Doreen Mollenhauer,
Sangam Chatterjee,
Stefanie Dehnen
![Advanced Optical Materials White‐Light Generation Upon In‐Situ Amorphization of Single Crystals of [{(Me3P)3AuSn}(PhSn)3S6] and [{(Et3P)3AgSn}(PhSn)3S6]](https://pericles.pericles-prod.literatumonline.com/cms/attachment/9951670d-45d7-4a7e-af41-f1407a64baae/adom201801793-gra-0001-m.png)
New molecular materials with extreme nonlinear optical properties based on adamantane‐type organotin sulfide clusters are reported, allowing for more insight into their still unknown potential for white‐light generation (WLG). Experimental and theoretical studies on [{(R3P)3MSn}(PhSn)3S6] (R = Me, Et; M = Cu, Ag, Au) show the influence of different metallo‐ligands on material properties and the potential for WLG upon in‐situ amorphization.
Abstract
In order to gain more information on the white‐light generation by amorphous molecular materials, the influence of metal complex substituents on the photophysical properties of potential white‐light emitters is investigated. Three compounds of the general type [{(R3P)3MSn}{PhSn}3S6)], with R/M = Me/Au (1), Et/Ag (4), and Me/Cu (5), are produced by reactions of the organotin sulfide cluster [(PhSn)4S6] (A) with the corresponding coinage metal complexes [M(PR3)3Cl]. Excess of the gold complex in the reaction leads to rearrangement and formation of [Au(PMe3)4][Au(PMe3)2][(PhSnCl)3S4] (2). The use of PMe3 instead of PEt3 in the reaction with the silver salt causes decomposition and affords [(Me3P)3AgSnCl3] (3). All compounds are structurally characterized, and the necessity of sterically stabilizing PEt3 groups at the silver complex in 4 are rationalized by density functional theory (DFT) calculations. Measurements of the photophysical properties of 1, 4, and 5 show that the introduction of the metallo‐ligands indeed affects the materials properties, and at the same time confirm that the reduction of the molecular symmetry alone is not a sufficient condition for white‐light generation (WLG), which still requires amorphicity of the compound. This is realized for 1 and 4 in situ, while reabsorption processes inhibit WLG in case of the copper compound 5.
13 May 00:35
by Jun Sawada,
Daisuke Aoki,
Hideyuki Otsuka,
Toshikazu Takata
Stretching out: Rotaxane crosslinkers (RC_Rs) with two radically polymerizable vinyl groups were synthesized to evaluate the mobility of the components in determining the properties of rotaxane‐crosslinked polymers (RCP Rs). RCP_Et exhibits the lowest component mobility, as reflected in inferior mechanical strength and stretching ability of the RCP compared to those with components with good (R=Me) and high (R=H) mobility.
Abstract
Three component mobility controlling vinylic rotaxane crosslinkers with two radically polymerizable vinyl groups (RC_Rs) were synthesized to prove that the mobility of the components of the RC_Rs plays a crucial role in determining the properties of rotaxane‐crosslinked polymers (RCPs). RC_Rs (R=H, Me, or Et) were obtained from living ring‐opening polymerization. RCP_Et was prepared using RC_Et, which exhibits the lowest component mobility. The low component mobility is reflected in inferior mechanical strength and stretching ability in tensile stress tests compared to components with good (R=Me) and high (R=H) mobility. However, RCP_Et exhibited significantly higher stress and strain values than the corresponding covalently crosslinked polymers (CCP_Rs). These results indicate that a suitable component mobility substantially enhances the mechanical strength of RCPs. This behavior could serve as a guiding principle for the molecular design of advanced RCs.