(TMTSF)2ClO4 is a quasi-one-dimensional organic conductor and superconductor with Tc=1.4 K, and one of at least two Bechgaard salts observed to have upper critical fields far exceeding the paramagnetic limit. Nevertheless, the 77Se NMR Knight shift at low fields reveals a decrease in spin susceptibility chi(s) consistent with singlet spin pairing. The field dependence of the spin-lattice relaxation rate at 100 mK exhibits a sharp crossover (or phase transition) at a field Hs approximately 15 kOe, to a regime where chi(s) is close to the normal state value, even though Hc2>> Hs.

A general synthetic route to a novel type of triamino-substituted planar carbenium ions (5) is reported. The synthetic method is based on a facile and selective nucleophilic aromatic substitution on the tris(2,4,6-trimethoxyphenyl)carbenium ion (1) with amines and gives access to a wide variety of more complex aminosubstituted carbenium ions. X-ray crystallography shows that the 2,6,10-tris(N-pyrrolidinyl)-4,8,12-trioxatriangulenium ion (5b) is planar and forms segregated stacks of cations and PF 6 anions in the solid phase. The stability of the 2,6,10-tris(diethylamino)-4,8,12-trioxatriangulenium ion 5a is expressed as the pK R+ value, which is determined in strongly basic nonaqueous solution on the basis of a new acidity function C_. The pK R+ value of 5a is measured to be 19.7, which is 10 orders of magnitude higher than the values found for the most stable carbenium ions previously reported. Electrochemical reduction of compound 5a leads to rapid dimerization. Two consecutive one-electron oxidations are identified by cyclic voltammetry.

Dendrimers are three-dimensional macromolecular structures originating from a central core molecule and surrounded by successive addition of branching layers (generation). These structures exhibit a high degree of molecular uniformity, narrow molecular weight distribution, tunable size and shape characteristics, as well as multivalency. Collectively, these physicochemical characteristics together with advancements in design of biodegradable backbones have conferred many applications to dendrimers in formulation science and nanopharmaceutical developments. These have included the use of dendrimers as pro-drugs and vehicles for solubilization, encapsulation, complexation, delivery, and site-specific targeting of small-molecule drugs, biopharmaceuticals, and contrast agents. We briefly review these advances, paying particular attention to attributes that make dendrimers versatile for drug formulation as well as challenging issues surrounding the future development of dendrimer-based medicines.

Dendrimer science has exploded onto the polymer science scene as the fourth major class of polymer architecture. Capturing the history of dendrimer discovery to the present day, this book addresses all the essential information for newcomers and those experienced in the field, including: • Fundamental theory, chemistry and physics of the 'dendritic state' • Synthetic strategies (click chemistry, self-assembly, and so on) • Dendron/dendrimer characterization techniques • Architecturally driven 'dendritic effects' • Developments in scientific and commercial applications • Convergence with nanotechnology, including dendrimer-based nanodevices, nanomaterials, nanotoxicology and nanomedicine • Dendrimers as a window to a new nano-periodic system. Including first-hand accounts from pre-1995 pioneers, progress in the dendrimer field is brought to life with anticipated developments for the future. This is the ideal book for researchers in both academia and industry who need a complete introduction to the 'dendritic state' with a special focus on dendrimer and dendron polymer science.

Molecular redox levels can be used to modulate tunneling currents through single or small numbers of molecules and induce molecular electronic device function. While most of these devices require cryogenic conditions, room temperature operation has been demonstrated by using electrochemical gating in aqueous environments. The latter have, however, serious shortcomings with a view on their relatively high volatility and narrow stability ranges in terms of potential. Here we report the first-time use of an ionic liquid, 1-butyl-3-methylimidazoliumhexafluorophosphate (BMI), as an electrochemical gate in a Scanning Tunneling Microscope (STM) configuration. Ionic liquids are known to have a very low vapor pressure, and accessible potential ranges are in principle large, up to 6 V. In a proof-of-principle experiment, we show how a heteroleptic redox-active Os bisterpyridine complex (Ossac) can be brought to exhibit both transistor and diode function in this novel environment at room temperature. This renders ionic liquids an attractive gating medium for configurations where back-gating is difficult to implement (e.g., break-junction techniques) or experimental conditions prohibit the use of aqueous or organic electrolyte media (vacuum or high temperatures). From an applied perspective, they represent a step toward solid-state molecular electronics with electrochemical gating.