An Accelerated Modular-Orthogonal Ni-Catalyzed Methodology to Symmetric and Nonsymmetric Constitutional Isomeric AB2 to AB9 Dendrons Exhibiting Unprecedented Self-Organizing Principles.

Five libraries of natural and synthetic phenolic acids containing five AB3, ten constitutional isomeric AB2, one AB4, and one AB5 were previously synthesized and reported by our laboratory in 5 to 11 steps. They were employed to construct seven libraries of self-assembling dendrons, by divergent generational, deconstruction, and combined approaches, enabling the discovery of a diversity of supramolecular assemblies including Frank-Kasper phases, soft quasicrystals, and complex helical organizations, some undergoing deracemization in the crystal state. However, higher substitution patterns within a single dendron were not accessible. Here we report three libraries consisting of 30 symmetric and nonsymmetric constitutional isomeric phenolic acids with unprecedented sequenced patterns, including two AB2, three AB3, eight AB4, five AB5, six AB6, three AB7, two AB8, and one AB9 synthesized by accelerated modular-orthogonal Ni-catalyzed borylation and cross-coupling. A single etherification step with 4-(n-dodecyloxy)benzyl chloride transformed all these phenolic acids, of interest also for other applications, into self-assembling dendrons. Despite this synthetic simplicity, they led to a diversity of unprecedented self-organizing principles: lamellar structures of interest for biological membrane mimics, helical columnar assemblies from rigid-solid angle dendrons forming Tobacco Mosaic Virus-like assemblies, columnar organizations from adaptable-solid angle dendrons forming disordered micellar-like nonhelical columns, columns from supramolecular spheres, five body-centered cubic phases displaying supramolecular orientational memory, rarely encountered in previous libraries forming predominantly Frank-Kasper phases, and two Frank-Kasper phases. Lessons from these self-organizing principles, discovered within a single generation of self-assembling dendrons, may help elaborate design principles for complex helical and nonhelical organizations of synthetic and biological matter.

Correlating Lithium Hydroxyl Accumulation with Capacity Retention in V2O5 Aerogel Cathodes.

V2O5 aerogels are capable of reversibly intercalating more than 5 Li(+)/V2O5 but suffer from lifetime issues due to their poor capacity retention upon cycling. We employed a range of material characterization and electrochemical techniques along with atomic pair distribution function, X-ray photoelectron spectroscopy, and density functional theory to determine the origin of the capacity fading in V2O5 aerogel cathodes. In addition to the expected vanadium redox due to intercalation, we observed LiOH species that formed upon discharge and were only partially removed after charging, resulting in an accumulation of electrochemically inactive LiOH over each cycle. Our results indicate that the tightly bound water that is necessary for maintaining the aerogel structure is also inherently responsible for the capacity fade.

Air-stable nickel precatalysts for fast and quantitative cross-coupling of aryl sulfamates with aryl neopentylglycolboronates at room temperature.

A library containing 10 air-stable Ni(II)X(Aryl)(PCy3)2 σ-complexes as precatalysts (X = Cl, Br, OTs, OMs, aryl = 1-naphthyl, 2-naphthyl; X = Cl, 1-acenaphthenyl, 1-(2-methoxynaphthyl), 9-phenanthrenyl, 9-anthracyl) was synthesized and demonstrated to quantitatively cross-couple 2-methoxyphenyl dimethylsulfamate with methyl 4-(5,5-dimethyl-1,3,2-dioxaborinane-2-yl)benzoate at 23 °C in dry THF in the presence of K3PO4(H2O)3.2 in less than 60 min. Lower or higher amounts of H2O in K3PO4 and as received THF mediate the same transformation in a maximum three times longer reaction time.