Ternary π-π Stacking Complexes by Allosteric Regulation in Multilayer Nanographenes.

Construction of π-π stacking supramolecular complexes with more than two different components is challenging due to the weak and directionless nature of dispersion interactions. Here, we report ternary complexes of a ditopic nanographene tetraimide (), α-substituted phthalocyanine (), and polyaromatic hydrocarbons (PAHs) in solution and the crystalline state via allosteric regulation. Binding of one gives rise to significant distortion and conformational changes in that in turn lead to the inhibition of the second binding of .

'Invisible' Molecular Dynamics Revealed for a Conformationally Chiral π-Stacked Perylene Bisimide Foldamer.

Whilst energetic and kinetic aspects of folding processes are meanwhile well understood for natural biomacromolecules, the folding dynamics in so far studied artificial foldamer counterparts remain largely unexplored. This is due to the low energy barriers between their conformational isomers that make the dynamic processes undetectable with conventional methods such as UV/Vis absorption, fluorescence, and NMR spectroscopy, making such processes 'invisible'. Here we present an asymmetric perylene bisimide dimer (bis-PBI 1) that possesses conformational chirality in its folded state.

Room-Temperature Near-Infrared Phosphorescence from C Nanographene Tetraimide by π-Stacking Complexation with Platinum Porphyrin.

Near-Infrared (NIR) phosphorescence at room temperature is challenging to achieve for organic molecules due to negligible spin-orbit coupling and a low energy gap leading to fast non-radiative transitions. Here, we show a supramolecular host-guest strategy to harvest the energy from the low-lying triplet state of C nanographene tetraimide 1. H NMR and X-ray analysis confirmed the 1 : 2 stoichiometric binding of a Pt(II) porphyrin on the two π-surfaces of 1.

Dirofilariasis Presenting as Orbital Abscess Complicating Ethmoid Sinusitis.

Dirofilariasis in deep tissue plane is seldom reported in literature. A 58 year old woman presented with right orbital abscess complicating ethmoid sinusitis. She underwent endoscopic ethmoidectomy with abscess drainage where a dirofilaria worm was extracted.

C Nanographene Tetraimide-A Receptor for Phthalocyanines with Subnanomolar Affinity.

Phthalocyanines are extensively used by the dye and pigment industry and in photovoltaic and photodynamic therapy research due to their intense absorption of visible light, outstanding stability, and versatility. As pigments, the unsubstituted phthalocyanines are insoluble owing to strong intermolecular π-π-stacking interactions, which causes limitations for the solution chemistry for both free base and metalated phthalocyanines. Here we show a supramolecular host-guest strategy to dissolve phthalocyanines into solution.

Supramolecular Substructure of C-Embedded Schwarzite.

Herein we present a new concept of carbon allotrope, namely, fullerene-embedded schwarzite. We isolated crystals of fullerene embedded in 4 equiv of a negatively curved polycyclic aromatic hydrocarbon (PAH), , which could be viewed as a substructure of the hypothetical fullerene-schwarzite complex. On the basis of crystal structure, the stability of the complex (C⊂()) was studied by theoretical methods (ALMO-EDA), showing that the noncovalent interactions driven by dispersion forces is key for stabilizing the complex, which was further supported by noncovalent interactions (NCI) plots and Hirshfeld-surface analyses.

Multilayer stacks of polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) show promise for applications in functional devices such as organic photovoltaics and field-effect transistors, but, although nanometre-sized PAHs-often referred to as nanographenes-have been well investigated as single-layer molecules, their multilayer counterparts remain rather unexplored. Here we show the assembly of a C nanographene derivative (comprising a planar core decorated with four meta-terphenyl-imide moieties at its periphery) into multilayer stacks with smaller PAHs ranging from naphthalene to ovalene and hexabenzocoronene. The functionalized C nanographene serves as a ditopic host that can accommodate a smaller PAH on either side of its planar core, in cavities delimited by its bulky imide substituents.

Palladium-Catalyzed [3+2] Annulation of Naphthalimide Acceptors and Thiophene Donors.

Donor-acceptor (D-A) dyes constitute one of the fundamental structural motifs of functional organic materials. In most cases, the donor and acceptor moieties are connected by a single bond, which could potentially be replaced by a fused aromatic ring to enhance the rigidity and conjugation of the dye moieties. However, there is still a lack of synthetic methodologies for such fused D-A systems.

Distinct Crystalline Aromatic Structural Motifs: Identification, Classification, and Implications.

Spatial noncovalent helical organization of nucleobases in DNA and radial organization of chromophores in natural light-harvesting systems are fascinating yet enigmatic. Understanding the numerous weak interactions that drive the formation of elegant supramolecular architectures in native natural systems and developing bioinspired design strategies have seen a surge of interest in recent decades. Self-assembly of functional chromophores in the crystalline phase is a definitive strategy to identify novel molecule-molecule interactions, in particular, atom-atom interactions, and to understand the synergistic nature of noncovalent interactions that stabilizes the supramolecular organization.

Anomalous Halogen-Halogen Interaction Assists Radial Chromophoric Assembly.

The design of highly efficient supramolecular architectures that mimic competent natural systems requires a comprehensive knowledge of noncovalent interactions. Halogen bonding is an excellent noncovalent interaction that forms halogen-halogen (X) as well as trihalogen interacting synthons. Herein, we report the first observation of a symmetric radial assembly of chromophores ( R3̅ c space group) composed of a stable hexabromine interacting synthon (Br) that further push the limits of our understanding on the nature, role, and potential of noncovalent halogen bonding.

Structure-Packing-Property Correlation of Self-Sorted Versus Interdigitated Assembly in TTF⋅TCNQ-Based Charge-Transport Materials.

Among the various donor-acceptor (D-A) charge-transfer co-crystals investigated in the past few decades, tetrathiafulvalene-tetracyanoquinodimethane (F⋅Q, popularly known as TTF⋅TCNQ)-based co-crystals have fascinated materials chemists owing to their exceptional conducting and magnetic properties that arise from the packing in crystal structures. Here, crystallographic information files of eighteen F⋅Q-based co-crystals are extracted from the Cambridge Structural Database (CSD) and classified into Class 1 (D-on-D and A-on-A segregated stacks; F⋅Q, F1⋅Q-F6⋅Q, and F⋅Q1), Class 2 (-A-D-A-D-A-D- mixed stacks; F6a⋅Q-F11⋅Q and F⋅Q2), and Class 3 [-A-D-A-A-D-A-; Class 3a (F12⋅Q and F13⋅Q) and -D-D-A-A-; Class 3b (F14⋅Q)] systems according to their packing modes. Hirshfeld surface analysis, PIXEL energy calculations, and quantum theory of atoms in molecules (QTAIM) analysis are performed on the selected multicomponent charge-transfer crystals for the first time, in an attempt to explore the driving forces that give rise to different classes of 3 D crystal packing, which in turn mandates the expedient electronic properties exhibited by the investigated co-crystals.

Assessing the Quality of Services Provided in the Teaching Hospitals: A Case Study of Iran.

Service quality is the most important factor in the success of health care organizations; because of their vital and important services, even very small errors can be followed by great and irreparable harm and damage. This study aimed to assess the quality of services provided in the teaching hospitals affiliated to Shiraz University of Medical Sciences in 2015. This is an applied, cross-sectional, and descriptive-analytical study conducted in 2015 in the teaching hospitals affiliated to Shiraz University of Medical Sciences.