Chiral Cyclic [n]Spirobifluorenylenes: Carbon Nanorings Consisting of Helically Arranged Quaterphenyl Rods Illustrating Partial Units of Woven Patterns

Chiral cyclic [n]spirobifluorenylenes consisting of helically arranged quaterphenyl rods, illustrating partial units of woven patterns, were designed and synthesized as a new family of carbon nanorings. The synthesis was accomplished by the Ni(0)-mediated Yamamoto-coupling of chiral spirobifluorene building blocks. The structures of the cyclic 3- and 4-mers were determined by X-ray crystallographic analysis. These carbon nanorings exhibited a strong violet colored emission with high quantum yields in solution (95%, 93%, and 94% for 3-, 4-, and 5-mer, respectively). Other spectroscopic properties, including their chiroptical properties, were also investigated. The gvalues for circularly polarized luminescence were found to be in the order of 10-3, where that of the 4-mer showed a relatively higher value 8.5 x 10-3. Characteristic spiroconjugation induced by multiple (≧ 3) bifluorenyl units, for example the even-odd effect of the number of units in the matching of the sign of the orbitals, were also revealed by DFT calculations.

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Chiral Cyclic [n]Spirobifluorenylenes: Carbon Nanorings Consisting of Helically Arranged Quaterphenyl Rods Illustrating Partial Units of Woven Patterns

10.26434/chemrxiv.12005994 ◽

2020 ◽

Author(s):

Kaige Zhu, ◽

Kosuke Kamochi ◽

Takuya Kodama ◽

Mamoru Tobisu ◽

Toru Amaya

Keyword(s):

Building Blocks ◽

Spectroscopic Properties ◽

Crystallographic Analysis ◽

Quantum Yields ◽

X Ray ◽

New Family ◽

Circularly Polarized Luminescence ◽

Polarized Luminescence ◽

Yamamoto Coupling ◽

Carbon Nanorings

Chiral cyclic [n]spirobifluorenylenes consisting of helically arranged quaterphenyl rods, illustrating partial units of woven patterns, were designed and synthesized as a new family of carbon nanorings. The synthesis was accomplished by the Ni(0)-mediated Yamamoto-coupling of chiral spirobifluorene building blocks. The structures of the cyclic 3-, 4-, and 5-mers were determined by X-ray crystallographic analysis. These carbon nanorings exhibited a strong violet colored emission with high quantum yields in solution (95%, 93%, and 94% for 3-, 4-, and 5-mer, respectively). Other spectroscopic properties, including their chiroptical properties, were also investigated. The g-values for circularly polarized luminescence were found to be in the order of 10-3, where that of the 4-mer showed a relatively higher value 8.5 x 10-3. Characteristic spiroconjugation induced by multiple 3) bifluorenyl units, for example the even-odd effect of the number of units in the matching of the sign of the orbitals, were also indicated by DFT calculations.

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X-Ray Crystallographic Analysis, EPR Studies, and Computational Calculations of a Cu(II) Tetramic Acid Complex

Bioinorganic Chemistry and Applications ◽

10.1155/2017/7895023 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10

Author(s):

Dimitrios Matiadis ◽

Dimitrios Tsironis ◽

Valentina Stefanou ◽

Olga Igglessi–Markopoulou ◽

Vickie McKee ◽

...

Keyword(s):

Self Assembly ◽

Copper Ions ◽

Copper Ion ◽

Spectroscopic Properties ◽

Crystallographic Analysis ◽

Computational Techniques ◽

Tetramic Acid ◽

Acid Complex ◽

X Ray ◽

Computational Calculations

In this work we present a structural and spectroscopic analysis of a copper(II) N-acetyl-5-arylidene tetramic acid by using both experimental and computational techniques. The crystal structure of the Cu(II) complex was determined by single crystal X-ray diffraction and shows that the copper ion lies on a centre of symmetry, with each ligand ion coordinated to two copper ions, forming a 2D sheet. Moreover, the EPR spectroscopic properties of the Cu(II) tetramic acid complex were also explored and discussed. Finally, a computational approach was performed in order to obtain a detailed and precise insight of product structures and properties. It is hoped that this study can enrich the field of functional supramolecular systems, giving place to the formation of coordination-driven self-assembly architectures.

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Introducing Molecular Diversity at the C20-position of Pregnenolone by the Formation of Spiro-2-morpholinones

Current Organic Synthesis ◽

10.2174/1570179414666171107161304 ◽

2018 ◽

Vol 15 (4) ◽

pp. 541-551

Author(s):

Guy Bertrand Djigoue ◽

Donald Poirier

Keyword(s):

Small Molecules ◽

Molecular Diversity ◽

Structural Diversity ◽

Building Blocks ◽

Dimensional Representation ◽

Huge Amount ◽

X Ray ◽

3 Dimensional ◽

New Family ◽

New Compounds

Aim and Objective: The development of small molecules that can interact with key therapeutic target represents an active field of research. Therefore, new approaches for increasing the molecular diversity of a starting material, such as a natural product, are needed. Herein, the carbonyl group present on a pregnane scaffold, or easily obtained from the oxidation of the corresponding alcohol, was used to obtain a series of diversified steroidal morpholinone derivatives. Materials and Methods: Using chemical synthesis, two levels of molecular diversity were introduced at position 20 of a C21-steroid scaffold. Nuclear magnetic resonance (NMR) spectroscopy and x-ray analysis were next used to characterize the morpholinone derivatives. Results: The C-20 carbonyl of pregnenolone was first transformed into an oxirane that reacted with an amino acid and the resulting amino alcohol was then cyclized to generate different spiro-2-morpholinones. X-ray analysis of one representative compound confirmed the 3-dimensional representation of this new family of diversified steroid derivatives. NMR analysis supported the expected structure and identified key markers of the chiral center configuration found in the 2-morpholinone moiety. Finally, the NH of the morpholinone ring was alkylated, thus increasing structural diversity. Conclusion: Considering the huge amount of building blocks (amino acids, bromobenzyl derivatives and ketones) that are commercially available, the strategy reported herein opens the door to the synthesis of diversified libraries of new compounds.

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meso-(2-Benzimidazolyl)-substituted BODIPYs: Synthesis, structures and spectroscopic properties

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424619501104 ◽

2020 ◽

Vol 24 (01n03) ◽

pp. 230-237

Author(s):

Hu Gao ◽

Chenhong Li ◽

Zhen Shen

Keyword(s):

Quantum Yield ◽

Spectroscopic Properties ◽

Crystallographic Analysis ◽

Membered Ring ◽

Quantum Yields ◽

Fluorescence Quantum Yields ◽

Nir Dyes ◽

Nir Fluorescence ◽

Yield Formula ◽

Post Modification

A series of meso-(2-benzimidazolyl)-substituted boron dipyrromethene (BODIPY) derivatives 3a–3c and 4 have been synthesized and characterized. The absorption and fluorescence bands of 3a are bathochromically shifted by 36 nm and 61 nm, respectively, compared with those of the meso-phenyl BODIPY in toluene. More importantly, the fluorescence quantum yields of these meso-(2-benzimidazolyl)-substituted BODIPYs (up to 0.45 in toluene) are much higher than those of the previously reported meso-heterocyclic BODIPYs. X-ray crystallographic analysis of the single crystal structure of 3a revealed that the dihedral angle of meso-benzimidazolyl ring and indacene plane (40.47[Formula: see text] ) is smaller compared with that of the meso-tolyl substituted BODIPY (61.4[Formula: see text] ). Replacement of the six-membered ring with a five-membered ring, as well as the absence of hydrogen at the imino-nitrogen, generated the reduced repulsion and the hydrogen bonding interaction. The increased planarity not only provided the substantial delocalization of [Formula: see text] electrons and red shifted the absorption and emission bands but also enhanced the fluorescence quantum yield by reducing free rotation induced nonradiative deactivation pathway. Furthermore, 3,5-distyryl coupled BODIPY 4 exhibits a NIR fluorescence band at 712 nm with moderate quantum yield ([Formula: see text] [Formula: see text] 0.3) in nonpolar and polar solvents, which indicate that meso-(2-benzimidazolyl) BODIPY acts as a good candidate for post modification toward NIR dyes for biological applications.

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Synthesis and circularly polarized luminescence properties of BINOL-derived bisbenzofuro[2,3-b:3’,2’-e]pyridines (BBZFPys)

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.16.32 ◽

2020 ◽

Vol 16 ◽

pp. 325-336 ◽

Cited By ~ 1

Author(s):

Ryo Takishima ◽

Yuji Nishii ◽

Tomoaki Hinoue ◽

Yoshitane Imai ◽

Masahiro Miura

Keyword(s):

Solid State ◽

Single Crystal ◽

Crystal Structures ◽

Optically Active ◽

Ring Closure ◽

Circularly Polarized ◽

X Ray ◽

Circularly Polarized Luminescence ◽

Polarized Luminescence ◽

Palladium Catalyzed

A series of optically active bisbenzofuro[2,3-b:3’,2’-e]pyridine (BBZFPy) derivatives was synthesized starting with the readily available (S)- and (R)-1,1’-bi-2-naphthols through a palladium-catalyzed multiple intramolecular C–H/C–H coupling as the key ring-closure step. The effect of terminal tert-butyl substituents on the BBZFPy skeleton was systematically investigated to uncover a unique aggregation-induced enhancement of CPL characteristics in the solid state. The crystal structures of the coupling products were also evaluated by single crystal X-ray analysis and the well-ordered intermolecular stacking arrangements appeared to be responsible for the enhanced CPL.

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Supramolecular self-assembly of chiral helical tubular polymers with amplified circularly polarized luminescence

Materials Chemistry Frontiers ◽

10.1039/d0qm00416b ◽

2020 ◽

Vol 4 (9) ◽

pp. 2772-2781

Author(s):

Xianhui Tang ◽

Dandan Chu ◽

Hong Jiang ◽

Wei Gong ◽

Chao Jiang ◽

...

Keyword(s):

Single Crystal ◽

Self Assembly ◽

Supramolecular Polymers ◽

Circularly Polarized ◽

X Ray ◽

Circularly Polarized Luminescence ◽

Polarized Luminescence

Two chiral tubular supramolecular polymers with amplified CPL that can be rationalized by single-crystal X-ray structures are demonstrated.

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Water-soluble chiral tetrazine derivatives: towards the application of circularly polarized luminescence from upper-excited states to photodynamic therapy

Chemical Science ◽

10.1039/c9sc00264b ◽

2019 ◽

Vol 10 (15) ◽

pp. 4163-4168 ◽

Cited By ~ 8

Author(s):

Tingchao He ◽

Can Ren ◽

Yu Luo ◽

Qi Wang ◽

Junzi Li ◽

...

Keyword(s):

Photodynamic Therapy ◽

Excited States ◽

Water Soluble ◽

Circularly Polarized ◽

Highly Efficient ◽

New Family ◽

Circularly Polarized Luminescence ◽

Polarized Luminescence

A new family of water-soluble tetrazine derivatives exhibits the first example of CPL from upper-excited states and highly efficient ISC.

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Quaternary structure of Limulus polyphemus hemocyanin

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081747 ◽

1978 ◽

Vol 36 (2) ◽

pp. 176-177

Author(s):

T. Wichertjes ◽

E.J. Kwak ◽

E.F.J. Van Bruggen

Keyword(s):

Electron Microscopy ◽

Functional Properties ◽

Horseshoe Crab ◽

Temperature Jump ◽

Quaternary Structure ◽

Crystallographic Analysis ◽

Limulus Polyphemus ◽

Oxygen Binding ◽

X Ray ◽

Intact Molecule

Hemocyanin of the horseshoe crab (Limulus polyphemus) has been studied in nany ways. Recently the structure, dissociation and reassembly was studied using electron microscopy of negatively stained specimens as the method of investigation. Crystallization of the protein proved to be possible and X-ray crystallographic analysis was started. Also fluorescence properties of the hemocyanin after dialysis against Tris-glycine buffer + 0.01 M EDTA pH 8.9 (so called “stripped” hemocyanin) and its fractions II and V were studied, as well as functional properties of the fractions by NMR. Finally the temperature-jump method was used for assaying the oxygen binding of the dissociating molecule and of preparations of isolated subunits. Nevertheless very little is known about the structure of the intact molecule. Schutter et al. suggested that the molecule possibly consists of two halves, combined in a staggered way, the halves themselves consisting of four subunits arranged in a square.

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Microstructure and crystal symmetry of Pb2Sr2(Y/Ca)Cu3O9−δ

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100173455 ◽

1990 ◽

Vol 48 (4) ◽

pp. 64-65

Author(s):

Y. P. Lin ◽

J. S. Xue ◽

J. E. Greedan

Keyword(s):

Electron Diffraction ◽

High Temperature Superconductors ◽

Carbon Film ◽

Basic Structure ◽

Crystal Symmetry ◽

X Ray Diffraction ◽

X Ray ◽

Space Groups ◽

New Family ◽

Convergent Beam

A new family of high temperature superconductors based on Pb2Sr2YCu3O9−δ has recently been reported. One method of improving Tc has been to replace Y partially with Ca. Although the basic structure of this type of superconductors is known, the detailed structure is still unclear, and various space groups has been proposed. In our work, crystals of Pb2Sr2YCu3O9−δ with dimensions up to 1 × 1 × 0.25.mm and with Tc of 84 K have been grown and their superconducting properties described. The defects and crystal symmetry have been investigated using electron microscopy performed on crushed crystals supported on a holey carbon film.Electron diffraction confirmed x-ray diffraction results which showed that the crystals are primitive orthorhombic with a=0.5383, b=0.5423 and c=1.5765 nm. Convergent Beam Electron Diffraction (CBED) patterns for the and axes are shown in Figs. 1 and 2 respectively.

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