Bin-Bin Ma

Bio: Bin-Bin Ma is an academic researcher from Nanjing University. The author has contributed to research in topics: Thiophene & Imidazole. The author has an hindex of 8, co-authored 9 publications receiving 134 citations.

From Monomers to π Stacks, from Nonconductive to Conductive: Syntheses, Characterization, and Crystal Structures of Benzidine Radical Cations

Abstract: Salts that contain radical cations of benzidine (BZ), 3,3',5,5'-tetramethylbenzidine (TMB), 2,2',6,6'-tetraisopropylbenzidine (TPB), and 4,4'-terphenyldiamine (DATP) have been isolated with weakly coordinating anions [Al(OR(F))(4)](-) (OR(F) = OC(CF(3))(3)) or SbF(6)(-). They were prepared by reaction of the respective silver(I) salts with stoichiometric amounts of benzidine or its alkyl-substituted derivatives in CH(2)Cl(2). The salts were characterized by UV absorption and EPR spectroscopy as well as by their single-crystal X-ray structures. Variable-temperature UV/Vis absorption spectra of BZ(·)(+)[Al(OR(F))(4)](-) and TMB(·)(+)[Al(OR(F))(4)](-) in acetonitrile indicate an equilibrium between monomeric free radical cations and a radical-cation dimer. In contrast, the absorption spectrum of TPB(·)(+)SbF(6)(-) in acetonitrile indicates that the oxidation of TPB only resulted in a monomeric radical cation. Single-crystal X-ray diffraction studies show that in the solid state BZ and its methylation derivative (TMB) form radical-cation π dimers upon oxidation, whereas that modified with isopropyl groups (TPB) becomes a monomeric free radical cation. By increasing the chain length, π stacks of π dimers are obtained for the radical cation of DATP. The single-crystal conductivity measurements show that monomerized or π-dimerized radicals (BZ(·)(+), TMB(·)(+), and TPB(·)(+)) are nonconductive, whereas the π-stacked radical (DATP(·)(+)) is conductive. A conduction mechanism between chains through π stacks is proposed.

Architectural Diversity for Anion-Mediated Self-Assembly of Four Pairs of Silver(I) Polymeric Isomers Having Linear and V-Shaped Imidazole/Thiophene/Imidazole Bridging Spacers

Abstract: A pair of linear and V-shaped acceptor–donor–acceptor (A–D–A) thiophene-based diazole structural isomers [i.e., 2,5-di(1H-imidazol-1-yl)thiophene (L1) and 3,4-di(1H-imidazol-1-yl)thiophene (L2)] have been used as bidentate bridging ligands to build Ag(I) fluorescent and semiconducting coordination polymers in the presence of different counterions. X-ray single-crystal diffraction analyses for eight complexes 1–8 reveal that they are four pairs of polymeric isomers formulated as {[Ag(L1)(CF3COO)]}n (1), {[Ag(L2)(CF3COO)]}n (2), [Ag(L1)(NO3)]n (3), {[Ag(L2)(NO3)]·(H2O)}n (4), [Ag(L1)(ClO4)]n (5), {[Ag(L2)](ClO4)}n (6), {[Ag(L1)(CH3CN)](PF6)}n (7), and {[Ag(L2)](PF6)·(CH3CN)}n (8). They exhibit abundant structural diversity, namely, a one-dimensional (1D) dimeric chain 1, a double-strand helix 2, a cosinelike chain 3, wavelike chains 4 and 8, linear chains 5 and 7, and a zigzag chain 6 because of the alterations of conformation for μ2 bridging ligands L1 and L2 (cis/cis, cis/trans, and trans/trans) and the p...

Synthesis, Crystal Structure, and Physical Property of Sterically Unprotected Thiophene/Phenylene Co‐Oligomer Radical Cations: A Conductive π–π Bonded Supermolecular meso‐Helix

Abstract: Sterically unprotected thiophene/phenylene co-oligomer radical cation salts BPnT(·+) [Al(OR(F))(4)](-) (OR(F)=OC(CF(3))(3), n=1-3) have been successfully synthesized. These newly synthesized salts have been characterized by UV/Vis-NIR absorption and EPR spectroscopy, and single-crystal X-ray diffraction analysis. Their conductivity increases with chain length. The formed meso-helical stacking by cross-overlapping radical cations of BP2T(·+) is distinct from previously reported face-to-face overlaps of sterically protected (co-)oligomer radical cations.

Dipyrido[3,2‐a:2′,3′‐c]phenazine‐Based Donor–Acceptor Aromatic Heterocyclic Compounds with Thienyl and Triphenylamino Chromophores at the 2,7‐ and/or 10,13‐Positions

Abstract: A series of T- and H-shaped donor-acceptor (D-A) types of dipyrido[3,2-a:2',3'-c]phenazine (DPPZ)-based molecules, extended by thienyl and triphenylamino chromophores at the 2,7-(bottom) and/or 10,13-positions (top), have been designed and prepared successfully. Synthetic, structural, thermal, spectral, and computational comparisons have been carried out for related compounds because of their adjustable intramolecular charge-transfer properties. It is noted that a pair of structural isomers (5 and 6) has been obtained, respectively, where distinguishable UV/Vis and fluorescence spectra, electrochemical activity, thermal stability, and bandgaps are observed. Furthermore, compounds 6, 8, 10, 11, 13, and 15 exhibit excellent thermal stability, and the Td10 values for them are found to range from 524 to 646 °C, which can be regarded as one of the best groups of thermally stable compounds among organic small molecules. In addition, theoretical calculations were performed, and the structure-property relationships were examined to reveal the effects of the position and number of donor arms on the DPPZ acceptor core.

Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications

Abstract: Two-dimensionally extended, polycyclic heteroaromatic molecules (heterocyclic nanographenes) are a highly versatile class of organic materials, applicable as functional chromophores and organic semiconductors. In this Review, we discuss the rich chemistry of large heteroaromatics, focusing on their synthesis, electronic properties, and applications in materials science. This Review summarizes the historical development and current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of modern heterocyclic chemistry.

Influence of Ancillary Ligands in Dye-Sensitized Solar Cells.

Abstract: Dye-sensitized solar cells (DSSCs) have motivated many researchers to develop various sensitizers with tailored properties involving anchoring and ancillary ligands. Ancillary ligands carry favorable light-harvesting abilities and are therefore crucial in determining the overall power conversion efficiencies. The use of ancillary ligands having aliphatic chains and/or π-extended aromatic units decreases charge recombination and permits the collection of a large fraction of sunlight. This review aims to provide insight into the relationship between ancillary ligand structure and DSSC properties, which can further guide the function-oriented design and synthesis of different sensitizers for DSSCs. This review outlines how the new and rapidly expanding class of chelating ancillary ligands bearing 2,2′-bipyridyl, 1,10-phenanthroline, carbene, dipyridylamine, pyridyl-benzimidazole, pyridyl-azolate, and other aromatic ligands provides a conduit for potentially enhancing the performance and stability of DSSCs. F...

From unsuccessful H2-activation with FLPs containing B(Ohfip)3 to a systematic evaluation of the Lewis acidity of 33 Lewis acids based on fluoride, chloride, hydride and methyl ion affinities

Abstract: The possibility of obtaining frustrated Lewis pairs (FLPs) suitable for H2-activation based on the Lewis acid B(Ohfip)31 (Ohfip = OC(H)(CF3)2) was investigated. In this context, the crystal structure of 1 as well as the crystal structure of the very weak adduct 1·NCMe was determined. When reacting solutions of 1 with H2 (1 bar) and selected phosphanes, amines, pyridines and N-heterocyclic carbenes, dihydrogen activation was never observed. Without H2, adduct formation with 1 was observed to be an equilibrium process, regardless of the Lewis base adduct. Thus, the thermodynamics of H2 activation of 1 in comparison with the well-known B(C6F5)3 was analyzed using DFT calculations in the gas phase and different solvents (CH2Cl2, ortho-difluorobenzene and acetonitrile). These investigations indicated that FLP chemistry based on 1 is considerably less favored than that with B(C6F5)3. This is in agreement with control NMR experiments indicating hydride transfer from [H–B(Ohfip)3]− upon reaction with B(C6F5)3, giving [H–B(C6F5)3]− and B(Ohfip)3 in toluene and also MeCN. Induced by these unsuccessful reactions, the Lewis acidity towards HSAB hard and soft ions was investigated for gaining a deeper insight. A unified reference system based on the trimethylsilyl compounds Me3Si–Y (Y = F, Cl, H, Me) and their respective ions Me3Si+/Y− calculated at the G3 level was chosen as the anchor point. The individual ion affinities were then assessed based on subsequent isodesmic reactions calculated at a much less expensive level (RI-)BP86/SV(P). This method was validated by systematic calculations of smaller reference systems at the frozen core CCSD(T) level with correlation effects extrapolated to a full quadruple-ζ basis. Overall, 33 common and frequently used Lewis acids were ranked with respect to their FIA, CIA, HIA and MIA (fluoride/chloride/hydride/methyl ion affinity).

One-Electron Oxidation of an Organic Molecule by B(C6F5)3; Isolation and Structures of Stable Non-para-substituted Triarylamine Cation Radical and Bis(triarylamine) Dication Diradicaloid

Abstract: The methylene-bridged triphenylamine 2 has been oxidized to planar radical cation 2•+ by B(C6F5)3 or Ag+. Further reaction of 2•+[Al(ORF)4]− and 2 with trace amounts of silver salt resulted in dication 32+, providing a rare example of structurally characterized bis(triarylamine) “bipolarons”. 32+ can be directly prepared by the reaction of 3 with 2 equiv of Ag+. X-ray structural analysis together with theoretical calculation shows that 32+ has singlet diradical character and is analogous to Chichibabin’s hydrocarbons.

Tuning Ground States of Bis(triarylamine) Dications: From a Closed‐Shell Singlet to a Diradicaloid with an Excited Triplet State

Abstract: Three bis(triarylamine) dications were isolated by using weakly coordinating anions. Their electronic structures in the ground state were investigated by various experiments in conjunction with theoretical calculations. The ground-state electronic structures of these species were tunable by substituent effects, with two of them as closed-shell singlets and one of them as an open-shell singlet in the solid state. The excited state of the latter is thermally accessible, indicated by EPR and SQUID measurements. The work provides a new and stable diradicaloid structure motif with an excited triplet sate.