Nathan D. Shapiro

Learn More
The last decade has witnessed dramatic growth in the number of reactions catalyzed by electrophilic gold complexes. While proposed mechanisms often invoke the intermediacy of gold-stabilized cationic species, the nature of bonding in these intermediates remains unclear. Herein, we propose that the carbon-gold bond in these intermediates is comprised of(More)
This Communication demonstrates the generation of over 300 phase-separated systems-ranging from two to six phases-from mixtures of aqueous solutions of polymers and surfactants. These aqueous multiphase systems (MuPSs) form self-assembling, thermodynamically stable step-gradients in density using a common solvent, water. The steps in density between phases(More)
Approaches to research in organic chemistry are as numerous as the reactions they describe. In this account, we describe our reactivity-based approach. Using our work in the area of gold-catalysis as a background, we discuss how a focus on reaction mechanism and reactivity paradigms can lead to the rapid discovery of new synthetic tools.
At its conception, the field of molecular electronics promised to provide the ability to engineer the rate of charge transport through the design of the molecular structure of electronic junctions. The hypothesis was that the electronic and geometrical structure of molecules in a junction would have a significant and predictable effect on the rate and(More)
Recently, gold-carbenoid species have been proposed as intermediates in gold-catalyzed enyne rearrangements.1 Additionally, the reaction of gold complexes with propargyl esters has been developed as an alternative approach to metal carbenoids capable of effecting olefin cyclopropanation;2,3 however, to date, the reaction of electrophilic metals with alkynes(More)
Chiral Brønsted acids (proton donors) have been shown to facilitate a broad range of asymmetric chemical transformations under catalytic conditions without requiring additional toxic or expensive metals. Although the catalysts developed thus far are remarkably effective at activating polarized functional groups, it is not clear whether organic Brønsted(More)
The liquid-metal eutectic of gallium and indium (EGaIn) is a useful electrode for making soft electrical contacts to self-assembled monolayers (SAMs). This electrode has, however, one feature whose effect on charge transport has been incompletely understood: a thin (approximately 0.7 nm) film-consisting primarily of Ga(2)O(3)-that covers its surface when in(More)
Intermediates possessing carbenoid character have recently been postulated in a number of gold-catalyzed rearrangements.1 In accord with this proposal, cyclopropane adducts are formed from the intermolecular reaction of the proposed gold(I)-carbenoid intermediates with olefins.2 To further examine the nature of these intermediates, we sought to explore(More)
This paper describes a method for the selective precipitation and purification of a monovalent protein (carbonic anhydrase is used as a demonstration) from cellular lysate using ammonium sulfate and oligovalent ligands. The oligovalent ligands induce the formation of protein-ligand aggregates, and at an appropriate concentration of dissolved ammonium(More)