Luminescent Molecular Octopuses with a Polyhedral Oligomeric Silsesquioxane (POSS) Core and Iridium(III) Polypyridine Arms: Synthesis, Aggregation Induced Emission, Cellular Uptake, and Bioimaging Studies

Abstract

A new class of luminescent molecular hybrids in which eight cyclometalated iridium(III) polypyridine complexes are grafted onto a polyhedral oligomeric silsesquioxane (POSS) unit [POSS‐{Ir(N^C)2(py‐im)}8](PF6)8 [py‐im=pyridine imine; HN^C=N‐phenylpyrazole (Hppz) (1 a), 2‐phenylpyridine (Hppy) (2 a), 2‐phenylquinoline (Hpq) (3 a)] were synthesized and characterized. On photoexcitation, the complexes showed intense and long‐lived orange‐red to red emission in fluid solutions at room temperature and in low‐temperature glasses. The photophysical properties including aggregation‐induced emission and biological properties of these complexes were studied and compared with those of their POSS‐free counterparts [Ir(N^C)2(py‐im)](PF6) [HN^C=Hppz (1 b), Hppy (2 b), Hpq (3 b)]. The (photo)cytotoxicity of the complexes was examined by the MTT assay, and their cellular uptake and intracellular localization were investigated by inductively coupled plasma‐mass spectrometry and laser‐scanning confocal microscopy.

Double organic groups‐containing polyhedral oligomeric silsesquioxane filled epoxy with enhanced fire safety

“…The inner SiOSi structure confers POSS with excellent thermal stability and low molecular polarization 19–21 . Organic R groups offer potential to improve the interactions between POSS and polymer, finally resulting in better mechanical property 22–24 . For an example, a series of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO)‐containing POSS was reported by Wu et al, 25 illustrating their ability to simultaneously improve the flame retardancy and haze of polycarbonate (PC), the compatibility of POSS with PC was enhanced due to π‐π stacking effect between DOPO and PC as well.…”

“…[19][20][21] Organic R groups offer potential to improve the interactions between POSS and polymer, finally resulting in better mechanical property. [22][23][24] For an example, a series of 9,10-dihydro-9oxa-10-phosphaphenanthrene-10-oxide (DOPO)-containing POSS was reported by Wu et al, 25 illustrating their ability to simultaneously improve the flame retardancy and haze of polycarbonate (PC), the compatibility of POSS with PC was enhanced due to π-π stacking effect between DOPO and PC as well. Zhang et al 3 reported a carboxyl-containing POSS, which endowed EP with enhanced flame retardancy and dielectric property.…”

Luminescent Neutral Cyclometalated Iridium(III) Complexes Featuring a Cubic Polyhedral Oligomeric Silsesquioxane for Lipid Droplet Imaging and Photocytotoxic Applications

“…35 We have recently developed molecular hybrids bearing a POSS core and eight cationic iridium(III) polypyridine pendants as bioimaging probes for live cells. 36 The attachment of a POSS unit has altered the usual mitochondrial localization property of cationic iridium(III) complexes and rendered the complexes to display aggregation-induced emission (AIE) and noncytotoxic properties. Considering the hydrophobic and lipophilic nature and high biocompatibility of the POSS nanocage, 37 we envisage that the incorporation of a lipophilic POSS unit into neutral iridium(III) complexes will generate a new family of phototheranostic reagents for organelle-targeted bioimaging and PDT.…”

“…Fluorescent POSS conjugates have been applied as bioimaging reagents, , modifiers for nanomaterials, delivery carriers for drugs, and phototherapeutic agents . We have recently developed molecular hybrids bearing a POSS core and eight cationic iridium­(III) polypyridine pendants as bioimaging probes for live cells . The attachment of a POSS unit has altered the usual mitochondrial localization property of cationic iridium­(III) complexes and rendered the complexes to display aggregation-induced emission (AIE) and noncytotoxic properties.…”

A Selenone-Functionalized Polyhedral Oligomeric Silsesquioxane for Selective Detection and Adsorption of Hg2+ ions in Aqueous Solutions

“…Compared to conventional organic molecules and polymers, POSS and their derivatives (typically T 8 , R 8 Si 8 O 12 ) possess many unique characteristics, such as rigid, high symmetric, well-defined, and ideal inorganic-organic hybrid structures, nanoscopic size (1-3 nm) and high functionality, etc, and thus having intriguing advantages, such as high thermal stability, mechanical properties (e.g., strength, modulus, rigidity), and improved quantum yields [1][2][3][4][5][6][7][8]. By virtue of these merits, they have been widely applied in many fields, including drug delivery [9], wastewater treatment [10,11], chemical sensors [12][13][14][15][16], energy transfer [17], bioimaging [18], chromatography [19], Polymers 2019, 11,2084 2 of 16 polymer electrolytes [20], catalysis [21][22][23], and membranes [24], etc. To realize these applications, it is crucial to incorporate various functionality into the POSS derivatives and/or materials.…”