Is there a shift to “active nanostructures”?

It has been suggested that an important transition in the long-run trajectory of nanotechnology development is a shift from passive to active nanostructures. Such a shift could present different or increased societal impacts and require new approaches for risk assessment. An active nanostructure “changes or evolves its state during its operation,” according to the National Science Foundation’s (2006) Active Nanostructures and Nanosystems grant solicitation. Active nanostructure examples include nanoelectromechanical systems (NEMS), nanomachines, self-healing materials, targeted drugs and chemicals, energy storage devices, and sensors. This article considers two questions: (a) Is there a “shift” to active nanostructures? (b) How can we characterize the prototypical areas into which active nanostructures may emerge? We build upon the NSF definition of active nanostructures to develop a research publication search strategy, with a particular intent to distinguish between passive and active nanotechnologies. We perform bibliometric analyses and describe the main publication trends from 1995 to 2008. We then describe the prototypes of research that emerge based on reading the abstracts and review papers encountered in our search. Preliminary results suggest that there is a sharp rise in active nanostructures publications in 2006, and this rise is maintained in 2007 and through to early 2008. We present a typology that can be used to describe the kind of active nanostructures that may be commercialized and regulated in the future.     

Acetylene-Mediated Borophosphene Dirac Materials as Efficient Anode Materials for Lithium-Ion Batteries

Generally, graphynes have been generated by the insertion of acetylenic content (−C≡C−) in the graphene network in different ratios. Also, several aesthetically pleasing architectures of two-dimensional (2D) flatlands have been reported with the incorporation of acetylenic linkers between the heteroatomic constituents. Prompted by the experimental realization of boron phosphide, which has provided new insights on the boron-pnictogen family, we have modelled novel forms of acetylene-mediated borophosphene nanosheets by joining the orthorhombic borophosphene stripes with different widths and with different atomic constituents using acetylenic linkers. Structural stabilities and properties of these novel forms have been assessed using first-principles calculations. Investigation of electronic band structure elucidates that all the novel forms show the linear band crossing closer to the Fermi level at Dirac point with distorted Dirac cones. The linearity in the hole and electronic bands impose the high Fermi velocity to the charge carriers close to that of graphene. Finally, we have also unravelled the propitious features of acetylene-mediated borophosphene nanosheets as anodes in Li-ion batteries.     

Crystal and Molecular Structure of 4-methoxy-carbonyl methyl-2,9-bis(phenylsulfonyl)-1,2,3,4-tetrahydro β-carboline : benzene solvate

The crystal structure of the title compound has been determined from X-ray diffraction data. The compound crystallizes from benzene in the monoclinic system, space group P2₁/a, with unit cell parameters: a = 12.676(2), b = 20.333(3), c = 12.947(2) Å, β = 113.12(1)°, Z = 4, V = 3069.0(8) ų. The trial structure was determined by direct methods and refined to a final R-index of 0.044. The six-membered heterocyclic ring adopts half-chair conformation. Of the two phenylsulfonyl groups, the one substituted at the indole nitrogen (N1) is equatorial, while the other (at N2) is axial. The methyl acetate group is approximately perpendicular to the β-carboline moiety.     

ChemInform Abstract: Structure and Stability of Water Chains (H2O)n,n = 5—20

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Dense energetic compounds of carbon,hydrogen, nitrogen,and oxygen atoms. V. 1,2,7,8-bisfuroxano-3,4,9,10-tetranitro-5, 11-dehydro-5H, 11H-benzotriazolo[2, 1-a]benzotriazole (BTBB)

A reaction between 2, 8-dichloro-4, 10-dinitro-5, 11-dehydro-5H, 11H-benzotriazolo[2, 1-a]-benzotriazole 8 and sodium azide in dimethyl sulfoxide produced 3, 9-diazido-4, 10-dinitro-5, 11-dehydro-5H, 11H-benzotriazolo [2, 1-a]benzotriazole 10 rather than the 2.8-diazido isomer 9 expected by direct displacement. Thermolytic elimination of nitrogen (2 moles) converted the dinitro diazide 10 to 3,4,9,10-bisfuroxano-5, 11-dehydro-5H, 11H-benzotriazolo[2, 1-a]benzotriazole 11 that was subsequently nitrated to give the 2,8-dinitro derivative 12 . Similar nitration converted the dinitro diazide 9 to the trinitro 15 and tetranitro 14 derivatives: thermolysis of the latter gave 1,2,7,8-bisfuroxano-4, 10-dinitro-5, 11-dehydro-5H, 11H-benzotriazolo[2, 1-a]-benzotriazole 16 . Nitration (100% HNO₃, CF₃SO₃H) converted compound 16 to the 3,4,10-trinitro derivative 17 , whereas a similar nitration (100% HNO₃, FSO₃H) gave the title compound BTBB, an insensitive high-energy, high-density (d 2.03 g/cc) molecule. © 1995 John Wiley & Sons, Inc.     

17O and 11B NMR spectroscopic study of substituted benzo[d]-2,2-difluoro-1,3,2-oxoniaoxaboratins

¹⁷O NMR data are reported for 10 benzo[d]-2,2-difluoro-1,3,2-oxoniaoxaboratins derived from various ortho-hydroxyacetophenones and for 2,2-difluoro-1,3,2-oxoniaoxaboratins derived from related hydroxyacetyl naphthalenes and hydroxybenzophenones. The signal for the carbonyl-like oxygen for these compounds is substantially shielded and appears at 288 ± 22 δ. The single bonded oxygen signal for the 1,3,2-oxoniaoxaboratins appears at 122 ± 6 δ, except for the naphthalene analogs, whose signal appears at 146 ± 10 δ. The ¹¹B NMR signal for these compounds is insensitive to structural changes and appears at 0.85 ± 0.25 δ. © 1995 John Wiley & Sons, Inc.     

Crystal Structure of t‐boc‐O‐benzyl‐L‐tyrosyl‐D‐alanyl‐L‐(O‐benzyl)‐glutamate : monohydrate

The crystal structure of a tripeptide, t‐boc‐O‐benzyl‐L‐tyrosyl‐D‐alanyl‐L‐(O‐benzyl)‐glutamate has been determined by direct methods, and refined by full‐matrix least squares procedures to a final R‐index of 0.060. The peptide conformation corresponds to a reverse turn — Type II , stabilized by a 4 — 1 N‐H...O hydrogen bond, with the amide proton also forming a bifurcated hydrogen bond to an oxygen atom from the C‐terminus of a neighbouring molecule.