Multifunctional Tubular Organic Cage‐Supported Ultrafine Palladium Nanoparticles for Sequential Catalysis

Abstract

The imine condensation reaction of 5,5'-(benzo[c]-[1,2,5]thiadiazole-4,7-diyl)diisophthalaldehyde with cyclohexanediamine resulted in as hape-persistent multifunctional tubular organic cage (MTC1). It exhibits selective fluorescence sensing towards divalent Pd ions with avery lowdetection limit (38 ppb), suggesting effective complexation between these two species.S ubsequent reduction of MTC1 and Pd(OAc) 2 with NaBH 4 afforded acage-supported catalyst with well-dispersed ultrafine Pd nanoparticles (NPs) in anarrowsizedistribution (1.9 AE 0.4 nm), denoted as Pd@MTC1-1/5. Suchu ltrafine Pd NPs in Pd@MTC1-1/5, in cooperation with photocatalytically active MTC1, enable efficient sequential reactions involving visible light-induced aerobic hydroxylation of 4-nitrophenylboronic acid to 4-nitrophenol and the following hydride reduction with NaBH 4 .T his is the first example of am ultifunctional organic cage capable of sensing,d irecting nanoparticle growth, and catalyzing sequential reactions.

Porous Pyrene Organic Cage with Unusual Absorption Bathochromic-Shift Enables Visible Light Photocatalysis

“…The observation by quartet electron spin resonance (ESR) signals for PyTC1 with the trapping agent, 5,5-dimethyl-1-pyrroline N-oxide, under the illumination of a blue LED lamp, suggested its capability of promoting superoxide anion radical (O 2 • ) − evolution via visible-light-driven electron transfer process (Supporting Information Figures S15 and S16), due to the high reduction potential of PyTC1 [−1.60 V vs standard hydrogen electrode (SHE)]. 56 Visible light-driven aerobic hydroxylation of benzeneboronic acid in the presence of PyTC1 photoredox catalyst under air was selected as a model reaction (Table 1). [60][61][62][63][64] We chose co-solvent CD 3 CN/D 2 O as the reaction medium, where dry PyTC1 crystals as photocatalyst had negligible solubility and presented as a solid, according to our NMR spectral data (Supporting Information Figure S17).…”

“…The unique porous nature of POCs can facilitate the mass transfer of reactants and products in heterogeneous catalysis. [47][48][49][50][51][52][53][54][55][56][57][58][59] Moreover, the arrangement of chromophores within a cage and the assembly could tune their light-harvesting wavelength and utilization efficiency depending on the aggregation model. In this work, we demonstrate the first example of an unusual C-H ... π interaction-induced absorption bathochromic shift in POCs (denoted as PyTC1) upon their self-assembly in the solid-state (Scheme 1).…”

Guest-Mediated Hierarchical Self-Assembly of Dissymmetric Organic Cages to Form Supramolecular Ferroelectrics

“…Covalent organic cages have attracted considerable attention for the recent decade. [1][2][3][4][5][6][7][8] Their most important characteristic is the intrinsic porosity, 7 and this feature has been applied to selective recognition/separation, [2][3]9 sensing, 10 catalysis, [11][12] etc. The other characteristic of cages is the geometric diversity, 6,13 which provides a panoply of polyhedra including tetrahedron, [14][15] octahedron, cuboctahedron, 16 cube, 14,17 prism, [18][19][20] as well as catenated structures.…”

Efficient ethylene purification by a robust ethane-trapping porous organic cage

“…The discrete inherent nature of the POCs makes them possessing distinct advantages in solution processing, regeneration and post-synthesis modi cation [20][21][22][23] . Since the rst elegant work reported in 2009 by Cooper et al 24 , the number of POCs with different shapes, sizes and properties has increased substantially [25][26][27][28][29][30][31][32][33][34][35] , but robust POCs with high surface areas are still few, which highly hinder their practical applications in gas storage and separation. In the past decade, although the Brunauer-Emmett-Teller (BET) surface areas of the POCs have increased from the initial 624 m 2 g − 1 to 3758 m 2 g − 1 , the majority of POCs have BET values less than 1000 m 2 /g 36,37 .…”