The formation mechanism of metal cluster fullerenes ScN@C: force field development and molecular dynamics simulations.

Metal cluster fullerenes are a class of molecular nanomaterials with complex structures and novel properties. An in-depth study of their formation mechanism is a key topic for developing new high-yield synthesis methods and promoting the practical application of such molecular nanomaterials. To elucidate the formation mechanism of ScN@C, a representative sub-class of metal cluster fullerenes, this study developed a ReaxFF force field parameter set CNSc.

The formation mechanism of Sc-based metallofullerenes: a molecular dynamics simulation study.

The practical applications of endohedral metallofullerenes (EMFs) are mainly constrained by their low yields. Understanding the formation mechanisms is therefore crucial for developing methods for high-yield and selective synthesis. To address this, a novel force-field parameter set, "CSc.

Dimethylamino naphthalene-based fluorescent probes for hydrogen sulfide detection and living cell imaging.

Hydrogen sulfide shows great importance in various physiological and biochemical processes. The development of fluorescence probes for facile and efficient detection of HS has attracted increasing attention of researchers. Herein, we synthesized two fluorescence probes based on simple naphthalene structure for detection of HS.

The Preparation of Enantiopure [6]- and [7]Helicenes from Binaphthanol.

A general and efficient synthetic methodology for the preparation of enantio- and diastereopure [6]-, and [7]helicenes is developed. Commercially available chiral binaphthanols are utilized to generate the arylene-vinylene precursors, which undergo helical folding via photocyclization to give enantio- and diastereopure [6]-, and [7]helicenes. These optically pure helicenes could be easily obtained via silica gel column chromatography without the use of expensive HPLC or chiral resolution reagents.

Endohedral metal-nitride cluster ordering in metallofullerene-Ni(OEP) complexes and crystals: a theoretical study.

The ordering of endohedral clusterfullerenes Sc3N@C80 and YSc2N@C80 co-crystallized with Ni(OEP) and isolated complexes with Ni(OEP) have been investigated theoretically. Having used multiple orientations of M3N clusters inside the cages with Fibonacci sampling, we describe the effect of intermolecular interactions on the orientation of the endohedral cluster.

An atlas of endohedral ScS cluster fullerenes.

Structural identification is a difficult task in the study of metallofullerenes, but understanding of the mechanism of formation of these structures is a pre-requisite for new high-yield synthetic methods. Here, systematic density functional theory calculations demonstrate that metal sulfide fullerenes ScS@C have similar cage geometries from C to C and form a close-knit family of structures related by Endo-Kroto insertion/extrusion of C units and Stone-Wales isomerization transformations. The stabilities predicted for favoured isomers by DFT calculations are in good agreement with available experimental observations, have implications for the formation of metallofullerenes, and will aid structural identification from within the combinatorially vast pool of conceivable isomers.

From C(58) to C(62) and back: Stability, structural similarity, and ring current.

An increasing number of observations show that non-classical isomers may play an important role in the formation of fullerenes and their exo- and endo-derivatives. A quantum-mechanical study of all classical isomers of C , C , and C , and all non-classical isomers with at most one square or heptagonal face, was carried out. Calculations at the B3LYP/6-31G* level show that the favored isomers of C , C , and C have closely related structures and suggest plausible inter-conversion and growth pathways among low-energy isomers.

Structural interconnections and the role of heptagonal rings in endohedral trimetallic nitride template fullerenes.

Recent experiments indicate that fullerene isomers outside the classical definition can also encapsulate metallic atoms or clusters to form endohedral metallofullerenes. Our systematic study using DFT calculations, suggests that many heptagon-including nonclassical trimetallic nitride template fullerenes are similar in stability to their classical counterparts, and that conversion between low-energy nonclassical and classical parent cages via Endo-Kroto insertion/extrusion of C2 units and Stone-Wales isomerization may facilitate the formation of endohedral trimetallic nitride fullerenes. Close structural connections are found between favored isomers of trimetallic nitride template fullerenes from C78 to C82 .

Theoretical study on experimentally detected Sc2S@C84.

Sc(2)S@C(84) has recently been detected but not structurally characterized.1 Density functional theory calculations on C(84) and Sc(2)S@C(84) show that the favored isomer of Sc(2)S@C84 shares the same parent cage as Sc(2)C2@C(84), whereas Sc(2)S@C(84):51383, which violates the isolated-pentagon rule, is the second lowest energy isomer with the widest HOMO-LUMO gap and shows high kinetic stability. The analysis shows that Sc(2)S@C(84):51575 is favored when the temperature exceeds 2,800 K and it can transform into the most favorable isomer Sc(2)S@C(84):51591.

2 D manganese vanadate nanoflakes as high-performance anode for lithium-ion batteries.

Nanometer-sized flakes of MnV2O6 were synthesized by a hydrothermal method. No surfactant, expensive metal salt, or alkali reagent was used. These MnV2O6 nanoflakes present a high discharge capacity of 768 mA h g(-1) at 200 mA g(-1), good rate capacity, and excellent cycling stability.

Direct probing of the structure and electron transfer of fullerene/ferrocene hybrid on Au(111) electrodes by in situ electrochemical STM.

The electron donor-acceptor dyads are an emerging class of materials showing important applications in nonlinear optics, dye-sensitized solar cells, and molecular electronics. Investigation of their structure and electron transfer at the molecular level provides insights into the structure-property relationship and can benefit the design and preparation of electron donor-acceptor dyad materials. Herein, the interface adstructure and electron transfer of buckyferrocene Fe(C60Me5)Cp, a typical electron donor-acceptor dyad, is directly probed using in situ electrochemical scanning tunneling microscopy (STM) combined with theoretical simulations.

Site-selective effects on guest-molecular adsorption and fabrication of four-component architecture by higher order networks.

2D porous networks have attracted great attention as they can be used to immobilize functional units as guest molecules in a spatially ordered arrangement. In this work, a novel molecular hybrid network with two kinds of cavities was fabricated. Several kinds of guest molecules, such as coronene, copper(II) phthalocyanine (CuPc), triphenylene, heptanoic acid and fullerene molecules, can be immobilized into this template.

The roles of benzoic acid and water on the Michael reactions of pentanal and nitrostyrene catalyzed by diarylprolinol silyl ether.

The roles of benzoic acid and water on the Michael reaction of pentanal and nitrostyrene catalyzed by diarylprolinol silyl ether are revealed by density functional theory calculations. The calculations demonstrate that the benzoic acid is ready to attack the catalysts and form a hydrogen bond between the hydrogen atom of the COOH of benzoic acid and one of the N atoms of the catalyst. The complex formed from pentanal, catalyst and benzoic acid attacks nitroalkene and forms transition states.

Chiral zinc phenylalanine nanofibers with fluorescence.

Chiral Zn(II)/D-,L-phenylalanine (Phe) bio-coordination polymer nanofibers with fluorescence were prepared by fast coordination-assisted assembly. The synthetic strategy is based on the fact that the Zn2+ ions were linked to oxygen atoms from carboxylate groups of the D- or L-amino acid by coordination interactions to form the chiral polymers. The Zn(II)/D-,L-Phe nanofibers had homogeneous diameters in the range of 700-900 nm and ultra-long length in several hundred micrometers, and the surface of the fiber was extremely smooth.

Poly[dimethyl-ammonium [aquadi-μ(2)-oxalato-yttriate(III)] trihydrate].

The title complex, {(C(2)H(8)N)[Y(C(2)O(4))(2)(H(2)O)]·3H(2)O}(n), was obtained accidentally under hydro-thermal conditions. The Y(III) atom is chelated by four oxalate ligands and one water mol-ecule resulting in a distorted tricapped trigonal-prismatic geometry. Each oxalate ligand bridges two Y(III) atoms, thus generating a three-dimensional network with cavities in which the ammonium cations and lattice water mol-ecules reside.

Poly[dimethyl-ammonium [aquadi-μ(2)-oxalato-samarate(III)] trihydrate].

In the title complex, {(C(2)H(8)N)[Sm(C(2)O(4))(2)(H(2)O)]·3H(2)O}(n), the Sm(III) atom is chelated by four oxalate ligands and one water mol-ecule forming a distorted tricapped trigonal-prismatic geometry. Each oxalate ligand chelates to two Sm(III) atoms, generating a three-dimensional anionic network with cavities in which the ammonium cations and lattice water mol-ecules reside. Various O-H⋯O, N-H⋯O and C-H⋯O hydrogen-bonding inter-actions further stablize the crystal structure.

Geometrical and electronic rules in fullerene-based compounds.

The discovery of buckminsterfullerene C(60) opened up a new scientific area and stimulated the development of nanoscience and nanotechnology directly. Fullerene science has since emerged to include fullerenes, endohedral fullerenes (mainly metallofullerenes), exofullerenes, and carbon nanotubes as well. Herein, we look back at the development of fullerene science from the perspective of epistemology by highlighting the proposed main rules or criteria for understanding and predicting the structures and stability of fullerene-based compounds.

Syntheses, Structural Characterization and Thermoanalysis of Transition-Metal Compounds Derived from 3,5-Dinitropyridone.

Nine metal compounds of Mn(II), Zn(II) and Cd(II) derived from dinitropyridone ligands (3,5-dinitro-pyrid-2-one, 2HDNP; 3,5-dinitropyrid-4-one, 4HDNP and 3,5-dinitropyrid-4-one-N- hydroxide, 4HDNPO) were characterized by elemental analysis, FT-IR and partly by TG-DSC. Three of which were further structurally characterized by X-ray single-crystal diffraction analysis. The structures of the three compounds, Mn(4DNP)(2)(H(2)O)(4), 4, Zn(4DNPO)(2)(H(2)O)(4), 8, and Cd(4DNPO)(2)(H(2)O)(4), 9, crystallize in the monoclinic space group P2(1)/n and Z = 2, with a = 8.

A global search for the lowest energy isomer of C(26).

The complete set of 2333 isomers of C(26) fullerene composed of square, pentagonal, hexagonal, and heptagonal faces together with some noncage structures is investigated at the Hartree-Fock and density functional theory (DFT) levels. For the singlet states, a nonclassical isomer C(26)-10-01 with a square embedded is predicted by the DFT method as the lowest energy isomer, followed by the sole classical isomer C(26)-00-01. Further explorations reveal that the electronic ground state of C(26)-10-01 is triplet state in C(s) symmetry, while that of C(26)-00-01 corresponds to its quintet in D(3h) symmetry.

Nonclassical fullerenes with a heptagon violating the pentagon adjacency penalty rule.

Nonclassical fullerenes with heptagon(s) and their derivatives have attracted increasing attention, and the studies on them are performing to enrich the chemistry of carbon. Density functional theory calculations are performed on nonclassical fullerenes C(n) (n = 46, 48, 50, and 52) to give insight into their structures and stability. The calculated results demonstrate that the classical isomers generally satisfy the pentagon adjacency penalty rule.

catena-Poly[[(1,10-phenanthroline-κN,N')cadmium(II)]-μ-oxalato-κO,O:O,O].

In the title complex, [Cd(C(2)O(4))(C(12)H(8)N(2))](n), the Cd(II) atom has a distorted octa-hedral coordination, defined by four O atoms from two symmetry-related oxalate ligands and by two N atoms from a bidentate 1,10-phenanthroline ligand. Each oxalate ligand bridges two Cd(II) atoms, generating a zigzag chain structure propagating along [100]. The packing of the structure is consolidated by non-classical C-H⋯O hydrogen-bonding inter-actions.

[A flow injection on-line unequal flow complexation preconcentration procedure coupled with flame atomic absorption spectrometry for determination of lead in tap water].

A simple, environmentally friendly, cost-effective, and sensitive method was developed for the determination of trace lead in tap water by flow injection (FI) on-line unequal flow complexation preconcentration procedure coupled with flame atomic absorption spectrometry (FAAS). Compared with conventional preconcentration method, the unequal flow complexation preconcentration procedure, increased the flow rate of sample while decreased the flow rate of complexing agent. The new method decreased the dilution effect of sample caused by the chelating agent, increased the sorption preconcentration effect, and increased the enhancement factor.

Telomere DNA conformation change induced aggregation of gold nanoparticles as detected by plasmon resonance light scattering technique.

It has been reported that adsorption of uncoiled DNA (u-DNA) on the surface of gold nanoparticles (Au-NPs) can prevent the nanoparticle suspensions from aggregation even if in salt medium. Herein we report that quadruplex DNA (q-DNA), which is formed from uncoiled telomere DNA, via intramolecular hydrogen bonds in the presence of potassium ion, cannot keep Au-NPs stable, and the q-DNA/Au-NPs coexisting suspensions display aggregation tendency, giving plasmon resonance light scattering (PRLS) signals of Au-NPs. Mechanism investigations through a single point energy calculation on u- and q-structures of telomere DNA showed that q-DNA, compared with u-DNA, has a much higher surface negative charge density, symmetrical charge distribution and well self-structural stabilization, could not be adsorbed on the surface of Au-NPs.

[Flame atomic absorption spectrometric determination of copper and lead in beer after preconcentration using a rapid coprecipitation technique with 8-oxyquinoline].

A method was proposed for the determination of trace copper and lead in beer with flame atomic absorption spectrometry after preconcentration of copper and lead by rapid coprecipitation technique with 8-oxyquinoline-Mg(II) using manganese as an internal standard at pH 9. The standard addition recovery of lead is between 97.6%-103.

Comparative investigation of derivatives of C60 and its isomers.

To provide insight into the derivatization of fullerenes, extensive density functional theory calculations were performed on their hydrides and fluorides of several isomers of C60. The calculated results demonstrate that the hydrides and fluorides of isolated pentagon rule (IPR) C60 are less stable than those of non-IPR C60. These results indicate that derivatization may cause structural transformation of a fullerene; and that many more non-IPR fullerenes may be captured in the forms of derivatives.