Effect of Multiple Interactions on Face-On vs Edge-On Configurations of Butadiyne-Bridged Octa­dehydro­dibenzo[12]annulene Derivatives at the Liquid/Graphite Interface

We investigated the self-assembled monolayers of octa­dehydro­dibenzo[12]­annulene (DBA) derivatives to see the effect of multiple intermolecular interactions on the formation of face-on vs edge-on configurations of planar compounds having weak core to core interactions at the liquid/graphite interfaces by means of scanning tunneling microscopy (STM). A DBA derivative having an <i>N-</i>dodecylamide chain at each end of the π-core formed face-on mode self-assemblies at the interfaces of both 1-phenyloctane (PO) and 1-octanoic acid (OA) and graphite. On the other hand, another DBA having both <i>N-</i>dodecylamide chains and methoxymethyl groups formed an edge-on mode self-assembly at the PO/graphite interface. However, at the OA/graphite interface, it formed a face-on mode self-assembly due to the solvent–molecule hydrogen bonds which suppress the intermolecular interactions. These results indicate that by multiple interactions between substituents the edge-on mode of self-assembly can be stabilized, rendering the otherwise unfavorable pattern be formed preferentially

Effect of Multiple Interactions on Face-On vs Edge-On Configurations of Butadiyne-Bridged Octa­dehydro­dibenzo[12]annulene Derivatives at the Liquid/Graphite Interface

We investigated the self-assembled monolayers of octa­dehydro­dibenzo[12]­annulene (DBA) derivatives to see the effect of multiple intermolecular interactions on the formation of face-on vs edge-on configurations of planar compounds having weak core to core interactions at the liquid/graphite interfaces by means of scanning tunneling microscopy (STM). A DBA derivative having an <i>N-</i>dodecylamide chain at each end of the π-core formed face-on mode self-assemblies at the interfaces of both 1-phenyloctane (PO) and 1-octanoic acid (OA) and graphite. On the other hand, another DBA having both <i>N-</i>dodecylamide chains and methoxymethyl groups formed an edge-on mode self-assembly at the PO/graphite interface. However, at the OA/graphite interface, it formed a face-on mode self-assembly due to the solvent–molecule hydrogen bonds which suppress the intermolecular interactions. These results indicate that by multiple interactions between substituents the edge-on mode of self-assembly can be stabilized, rendering the otherwise unfavorable pattern be formed preferentially

Enhanced Photocatalytic Activity of Calix[4]arene-Based Donor–Acceptor Covalent Organic Frameworks by Dual Cocatalysts

The distinctive characteristics of covalent organic frameworks (COFs), including their high surface area, adjustable porosity, and sturdy chemical structure, render them appealing for potential use in photocatalytic applications. Nonetheless, the full utilization of their photocatalytic activity has been hindered by the limited charge separation and migration efficiencies of COFs, along with high exciton binding energies. In this research, calix[4]arene (C4A) and thiazolo[5,4-d]thiazole (TzTz) were selected as electron donor and acceptor units, respectively, to produce C4A-TzTz-COF with donor–acceptor (D–A) properties, which represents one of the most effective approaches for promoting charge separation and transport in organic semiconductors. As a control, C4A-PA-COF was synthesized, and it was observed that the photocatalytic hydrogen evolution rate of C4A-TzTz-COF with donor–acceptor (D–A) features was 7.3 times greater than that of the former. Additionally, Ag nanoparticles (NPs) and Pt NPs were sequentially deposited on the surface of C4A-TzTz-COF. Ag NPs serve as providers of hot electrons under the localized surface plasmon resonance (LSPR) effect, with the hot electrons being injected at the conduction band of C4A-TzTz-COF. Pt NPs, acting as catalytically active sites, effectively capture hot electrons for cocatalysis. Ultimately, the donor–acceptor structure of Pt–Ag3.0/C4A-TzTz-COF, featuring a bimetallic system, significantly enhances the photocatalytic activity in the visible light range, leading to a 2.2-fold increase in the photocatalytic hydrogen evolution rate over C4A-TzTz-COF. The synergistic effects of the dual cocatalysts not only facilitate charge separation and transfer but also enable the efficient utilization of solar energy for sustainable energy conversion. This study provides valuable insights into the design and development of advanced COF-based photocatalytic materials with enhanced performance, paving the way for their widespread application in renewable energy and environmental remediation technologies

Structural Modulation from 1D Chain to 3D Framework: Improved Thermostability, Insensitivity, and Energies of Two Nitrogen-Rich Energetic Coordination Polymers

Two new energetic coordination polymers (CPs) [Pb­(BT)­(H₂O)₃]_<i>n</i> (<b>1</b>) and [Pb₃(DOBT)₃(H₂O)₂]_<i>n</i>·(4H₂O)_<i>n</i> (<b>2</b>) with 1D and 3D structures were synthesized by employing two rational designed ligands, 1H,1′H-5,5′-bitetrazole (H₂BT) and 1H,1′H-[5,5′-bitetrazole]-1,1′-diol ligands (DHBT), respectively. Thermal analyses and sensitivity tests show that the 3D architecture reinforces the network of <b>2</b> which has higher thermal stability and lower sensitivity than that of <b>1</b>. Through oxygen-bomb combustion calorimetry the molar enthalpy of formation of <b>2</b> is derived to be much higher than that of <b>1</b> as well as the reported CPs. Herein, more importantly, the heats of detonation (Δ<i>H</i>_det) were calculated according to the decomposition products of TG-DSC-MS-FTIR simultaneous analyses for the first time. The calculated results show that Δ<i>H</i>_det of <b>2</b> is 23% higher than that of <b>1</b>. This research demonstrates that 3D energetic CP with outstanding energetic properties can be obtained through efficient and reasonable design

Structural Modulation from 1D Chain to 3D Framework: Improved Thermostability, Insensitivity, and Energies of Two Nitrogen-Rich Energetic Coordination Polymers

Two new energetic coordination polymers (CPs) [Pb­(BT)­(H₂O)₃]_<i>n</i> (<b>1</b>) and [Pb₃(DOBT)₃(H₂O)₂]_<i>n</i>·(4H₂O)_<i>n</i> (<b>2</b>) with 1D and 3D structures were synthesized by employing two rational designed ligands, 1H,1′H-5,5′-bitetrazole (H₂BT) and 1H,1′H-[5,5′-bitetrazole]-1,1′-diol ligands (DHBT), respectively. Thermal analyses and sensitivity tests show that the 3D architecture reinforces the network of <b>2</b> which has higher thermal stability and lower sensitivity than that of <b>1</b>. Through oxygen-bomb combustion calorimetry the molar enthalpy of formation of <b>2</b> is derived to be much higher than that of <b>1</b> as well as the reported CPs. Herein, more importantly, the heats of detonation (Δ<i>H</i>_det) were calculated according to the decomposition products of TG-DSC-MS-FTIR simultaneous analyses for the first time. The calculated results show that Δ<i>H</i>_det of <b>2</b> is 23% higher than that of <b>1</b>. This research demonstrates that 3D energetic CP with outstanding energetic properties can be obtained through efficient and reasonable design

Absorptive Behaviors and Photovoltaic Performance Enhancements of Alkoxy-Phenyl Modified Indacenodithieno[3,2‑<i>b</i>]thiophene-Based Nonfullerene Acceptors

Nonfullerene (NF) small molecular acceptors are very attractive for further improving the power conversion efficiencies (PCEs) of polymer solar cells (PSCs) to overcome the limited absorptive region and fixed-energy-level drawbacks of fullerene-based electronic acceptors (PC₆₁BM and PC₇₁BM). The acceptor–donor–acceptor (A-D-A)-type oligomers (<b>ITIC</b>) containing an electron-rich core (four hexyl-phenyl-substituted indacenodithieno­[3,2-<i>b</i>]­thiophene) as a donor motif sealed with 2-(3-oxo-2,3-dihydroinden-1-ylidene)-malononitrile as an acceptor motif has been intensively investigated, because of its excellent absorptive and photovoltaic properties. Side-chain modifications have been proven to be an effective approach to modulate the energy levels and absorptive behaviors of conjugated polymers, as well as conjugated small molecules. Through the introduction of various side-chain and end groups, a series of promisingly modified <b>ITIC</b>-based small molecules have been synthesized and well-studied. Herein, we reported three novel alkoxy-phenyl modified <b>ITIC</b>-type NF acceptors (namely, <b>pO-ITIC</b>, <b>mO-ITIC</b>, and <b>FpO-ITIC</b>), in which 4-hexyloxy-phenyl, 3-hexyloxy-phenyl, and 3-fluorine-4-hexyloxy-phenyl side-chains were connected on the indacenodithieno­[3,2-<i>b</i>]­thiophene core as the electron-donating segments of the A-D-A molecules. Both three small molecules exhibit good solubility in common solvents, finely tunable energy levels, and adjustable optical bandgaps. The 4-hexyloxy-phenyl and 3-hexyloxy-phenyl-substituted materials possess relatively low bandgaps (1.61 eV for <b>pO-ITIC</b> and 1.63 eV for <b>mO-ITIC</b>) and a 4.7% enhancement in the maximum extinction coefficient, compared to that of <b>ITIC</b>. As the result of the better absorption behaviors, inverted polymer solar cells based on <b>pO-ITIC</b> blended with <b>PTB7-Th</b> achieve an open-circuit voltage (<i>V</i>_oc) of 0.80 V, a short-circuit current (<i>J</i>_sc) of 14.79 mA/cm², and a fill factor (FF) of 59.1%, leading to a high-power conversion efficiency (PCE) of 7.51%, relative to the 7.31% PCE of <b>ITIC</b>-based device. By using a new thiazolothiazole-based wide-bandgap polymer (<b>PTZ-DO</b>, 1.98 eV) with deep HOMO energy level (−5.43 eV) to match the optical absorption and molecular energy levels with the three NF acceptors, excellent PCE values9.28% for <b>mO-ITIC</b> and 9.03% for <b>pO-ITIC</b>are obtained, which show increments of 15.3% and 12.2%, respectively, relative to that of <b>ITIC</b> (8.05%). This finding should offer useful guidelines for the design of novel NF acceptors for highly efficient PSCs through alkoxy-phenyl side-chains modified on the electron-donating moiety of A-D-A organic small molecules

Structural Modulation from 1D Chain to 3D Framework: Improved Thermostability, Insensitivity, and Energies of Two Nitrogen-Rich Energetic Coordination Polymers

Two new energetic coordination polymers (CPs) [Pb­(BT)­(H₂O)₃]_<i>n</i> (<b>1</b>) and [Pb₃(DOBT)₃(H₂O)₂]_<i>n</i>·(4H₂O)_<i>n</i> (<b>2</b>) with 1D and 3D structures were synthesized by employing two rational designed ligands, 1H,1′H-5,5′-bitetrazole (H₂BT) and 1H,1′H-[5,5′-bitetrazole]-1,1′-diol ligands (DHBT), respectively. Thermal analyses and sensitivity tests show that the 3D architecture reinforces the network of <b>2</b> which has higher thermal stability and lower sensitivity than that of <b>1</b>. Through oxygen-bomb combustion calorimetry the molar enthalpy of formation of <b>2</b> is derived to be much higher than that of <b>1</b> as well as the reported CPs. Herein, more importantly, the heats of detonation (Δ<i>H</i>_det) were calculated according to the decomposition products of TG-DSC-MS-FTIR simultaneous analyses for the first time. The calculated results show that Δ<i>H</i>_det of <b>2</b> is 23% higher than that of <b>1</b>. This research demonstrates that 3D energetic CP with outstanding energetic properties can be obtained through efficient and reasonable design

Self-Assembled Dehydro[24]annulene Monolayers at the Liquid/Solid Interface: Toward On-Surface Synthesis of Tubular π‑Conjugated Nanowires

We have studied the self-assembly behavior of dehydro[24]­annulene (D24A) derivatives <b>1</b>, <b>2a</b>–<b>2d</b>, and <b>3a</b>–<b>3c</b> at the liquid/solid interface using scanning tunneling microscopy (STM). Both the relative placement and the nature of the four D24A substituents strongly influence the self-assembly pattern. Overall, the eight D24A derivatives examined in this study display seven types of 2D packing patterns. The D24A derivatives <b>1</b>, <b>2a</b>, and <b>3a</b> have either two or four stearate groups and adopt face-on configurations of their macrocyclic cores with respect to the highly oriented pyrolytic graphite (HOPG) surface. Their 2D packing pattern is determined by the interchain spacings and number of stearate substituents. The D24A derivatives <b>2b</b>–<b>2d</b> and <b>3b</b>–<b>3c</b> bear hydrogen-bonding carbamate groups to further strengthen intermolecular interactions. Face-on patterns were also observed for most of these compounds, while an unstable edge-on self-assembly was observed in the case of <b>2b</b> at room temperature. Stable edge-on self-assemblies of D24A derivatives were sought for this work as an important stepping stone to achieving the on-surface topochemical polymerization of these carbon-rich macrocycles into tubular π-conjugated nanowires. The overall factors determining the 2D packing patterns of D24As at the liquid/solid interface are discussed on the basis of theoretical simulations, providing useful guidelines for controlling the self-assembly pattern of future D24A macrocycles