PubMed Health⌕ Search

Biomedical subjects

Emilio M Pérez

Publications and source records attributed to Emilio M Pérez.

7 recordsLinked to original sources
PubMed2006

exTTF as a building block for fullerene receptors. unexpected solvent-dependent positive homotropic cooperativity.

The first exTTF-based receptor for molecular recognition of fullerene is described. Unexpectedly, the receptor shows completely different binding modes in chlorobenzene and CHCl3/CS2 mixtures. In the aromatic solvent, the receptor binds C60 in a noncooperative fashion (nH = 1) with a Kassoc = (2.98 +/- 0.12) x 103 M-1, whereas in CHCl3/CS2 mixtures, it shows a marked positive homotropic cooperative effect (nH = 2.7) toward binding of C60, with an apparent binding constant of (3.56 +/- 0.16) x 103 M-1. The unique solvent-switchable behavior of our receptor might find use in the controlled self-assembly of exTTF-C60 donor-acceptor ensembles.

Journal Article↗
PubMed2005

Macroscopic transport by synthetic molecular machines.

Nature uses molecular motors and machines in virtually every significant biological process, but demonstrating that simpler artificial structures operating through the same gross mechanisms can be interfaced with-and perform physical tasks in-the macroscopic world represents a significant hurdle for molecular nanotechnology. Here we describe a wholly synthetic molecular system that converts an external energy source (light) into biased brownian motion to transport a macroscopic cargo and do measurable work. The millimetre-scale directional transport of a liquid on a surface is achieved by using the biased brownian motion of stimuli-responsive rotaxanes ('molecular shuttles') to expose or conceal fluoroalkane residues and thereby modify surface tension. The collective operation of a monolayer of the molecular shuttles is sufficient to power the movement of a microlitre droplet of diiodomethane up a twelve-degree incline.

Biomimetics↗
PubMed2004

A generic basis for some simple light-operated mechanical molecular machines.

A novel type of mechanical switch is described in which light-induced translation of a macrocycle in a [2]rotaxane quenches anthracene fluorescence. Features of the system include the remarkable 200:1 difference in fluorescence intensity between the two positional states of the molecule ( approximately 85:1 between one isomer and the photostationary state). In principle the same concept could be used for mechanically switching virtually any property that can be influenced by functional group proximity effects.

Amides↗
PubMed2003

Chiroptical switching in a bistable molecular shuttle.

Although various methods for switching the positions of macrocycles in bistable rotaxane-based molecular shuttles have been developed, exploiting such movements to trigger property changes has thus far received little attention. Here we describe one of the first examples of a property change achieved through a controlled large-amplitude translational motion in a rotaxane; a novel type of chiroptical switch is described, in which light-induced translation of the macrocycle along the thread of a [2]rotaxane produces a strong induced circular dichroism (ICD) response only when the macrocycle is hydrogen-bonded to a chiral peptide station.

Journal Article↗