Synthetic control over pore size and pore connectivity is the crowning achievement for porous metal-organic frameworks. The same level of control has not been achieved for molecular crystals, which are not defined by strong, directional intermolecular coordination bonds. Hence, molecular crystallization is inherently less controllable than framework crystallization, and there are fewer examples of 'reticular synthesis'-where multiple building blocks can be assembled according to a common assembly motif.Here, we apply a chiral recognition strategy to a new family of tubular covalent cages, to create both 1-D porous nanotubes and 3-D diamondoid pillared porous networks.The diamondoid networks are analogous to metal-organic frameworks prepared from tetrahedral metal nodes and linear, ditopic organic linkers. The crystal structures can be rationalized by computational lattice energy searches, which provide an in silico screening method to evaluate candidate molecular building blocks. These results are a blueprint for applying the 'node and strut' principles of reticular synthesis to molecular crystals.Despite many advances in supramolecular chemistry, it is still challenging to control molecular crystallization to create a specific, useful property. 1,2 This is important in the emerging area of porous molecular solids, 3 which have practical advantages such as solution processability. The crystal packing in porous molecular crystals defines the pore dimensions, which in turn define properties such as guest selectivity. 4,5 The same challenge-control over solid state structure-applies to all 2 functional molecular crystals because crystal packing defines physical properties such as electronic band gap and thermal or electrical conductivity.A central paradigm in crystal engineering is to synthesize building blocks, or 'tectons', with strong, directional interactions, such as hydrogen bonding 6 or metal-ligand binding, 7 which direct assembly into a targeted three-dimensional superstructure (Fig. 1). 1,2,8,9 For metal-organic frameworks (MOFs) and porous coordination polymers (PCPs), directional metal-ligand bonds are used to do this (Fig. 1a). [10][11][12][13][14] Likewise, hydrogen bonding can be used to create organic molecular crystals with defined network structures (Fig. 1b). 9,15,16 We have used chiral recognition to assemble porous organic cages 3 (POCs) into structures with 3-D pore channels (Fig. 1c). 3 POCs are rigid molecules with a permanent internal void that is accessible to guests via 'windows' in the cage. [17][18][19] Control of structure and function for POCs can be difficult, however, because slight changes in the molecular structure 19 or the crystallization solvent 20 can cause a profound change in the crystal packing. Chiral window-towindow interactions (Fig. 1e,f) can direct these POCs to assemble into 3-D pore networks in several cases, 19,21,22 but this is not ubiquitous. For example, some cages require specific solvents to template the window-to-window packing. 20 The chiral cage CC3-S (...

There are important considerations when choosing among formulation sizes for use in Trp manipulation studies, and the complete 7-h time-course data set of the typical plasma Trp measures presented here may help researchers decide which methodology best suits their needs.

We have performed experiments on single-wall carbon nanotube ͑SWNT͒ networks and compared with density-functional theory ͑DFT͒ calculations to identify the microscopic origin of the observed sensitivity of the network conductivity to physisorbed O 2 and N 2 . Previous DFT calculations of the transmission function for isolated pristine SWNTs have found physisorbed molecules have little influence on their conductivity. However, by calculating the four-terminal transmission function of crossed SWNT junctions, we show that physisorbed O 2 and N 2 do affect the junction's conductance. This may be understood as an increase in tunneling probability due to hopping via molecular orbitals. We find the effect is substantially larger for O 2 than for N 2 , and for semiconducting rather than metallic SWNTs junctions, in agreement with experiment.

A dinuclear oxo-Mo(V) complex 1 has been prepared which develops an intense absorption in the near-IR region (λ = 1340 nm; ε = 23 000 M-1 cm-1) on reversible one-electron oxidation to [1]+. This has formed the basis of a variable optical attenuator, whereby the intensity of near-IR laser light may be modulated over a range of 50 dB according to the electrical potential applied to the cell.

A simple, rapid isocratic liquid chromatographic procedure with ultraviolet and fluorimetric detection is described for the separation and quantification of L-tryptophan (Trp) and six of its kynurenine metabolites (kynurenine, 3-hydroxykynurenine, and 3-hydroxyanthranilic, kynurenic, xanthurenic and anthranilic acids). Using the Perkin Elmer LC 200 system, a reverse phase Synergi 4 μ fusion-RP80 A column (250 × 4.6 mm) (Phenomenex), and a mobile phase of 10 mM sodium dihydrogen phosphate: methanol (73:27, by vol) at pH 2.8 and a flow rate of 1.0–1.2 ml/min at 37 °C, a run took ∼13 min. The run took <7 min at 40 °C and a 1.4 ml/min flow rate. Limits of detection of all 7 analytes were 5–72 nM and their recoveries from human plasma and rat serum and liver varied between 62% and 111%. This simple method is suitable for high throughput work and can be further developed to include quinolinic acid and other Trp metabolites.