Search results for "Surfaces"

Determination of the electron-detachment energies of 2'-deoxyguanosine 5'-monophosphate anion: influence of the conformation.

2009

The vertical electron-detachment energies (VDEs) of the singly charged 2'-deoxyguanosine 5'-monophosphate anion (dGMP - ) are determined by using the multiconfigurational second-order perturbation CASPT2 method at the MP2 ground-state equilibrium geometry of relevant conformers. The origin of the unique low-energy band in the gas phase photoelectron spectrum of dGMP - , with maximum at around 5.05 eV, is unambiguously assigned to electron detachment from the highest occupied molecular orbital of π-character belonging to guanine fragment of a syn conformation. The presence of a short H-bond linking the 2-amino and phosphate groups, the guanine moiety acting as proton donor, is precisely resp…

Single chain magnet behaviour in an enantiopure chiral cobalt(II)–copper(II) one-dimensional compound

2010

The self-assembly of an enantiomerically pure, chiral dianionic oxamatocopper(II) complex with cobalt(II) ions leads to neutral oxamato-bridged heterobimetallic chains that combine chirality and slow magnetic relaxation, providing thus the first example of ‘‘chiral single chain magnets (CSCMs). Ruiz Garcia, Rafael, Rafael.Ruiz@uv.es ; Lloret Pastor, Francisco, Francisco.Lloret@uv.es

Template synthesis of multi-macrocycles by metathesis reaction.

2004

Selective heterodimerisation of tetraurea calix[4]arenes containing four or eight ω-alkenyl groups with a tetratosyl urea calix[4]arene has been effectively used to synthesize multi-macrocycles via metathesis reaction.

Two- and one-step cooperative spin transitions in Hofmann-like clathrates with enhanced loading capacity

2014

Structural, magnetic, calorimetric and Mo¨ssbauer studies of the cooperative spin crossover naphthalene and nitrobenzene clathrates of the novel FeII Hofmann-like porous metal–organic framework {Fe(bpb)[Pt(CN)4]}2Guest are described (bpb = bis(4-pyridyl)butadiyne).

Modular functionalized polyphosphines for supported materials: previously unobserved (31)P-NMR «through-space» ABCD spin systems and heterogeneous pa…

2014

The modular design of polyphosphines, diversely functionalized for facile immobilization on virtually any kind of support, is reported. Previously unobserved ABCD (31)P NMR spin-spin systems evidence the control exercised on the polyphosphines conformation. We illustrate the catalytic performance at low Pd loading of the recyclable immobilized polyphosphines in C-C bond formation reactions.

Polyamines containing naphthyl groups as pH-regulated molecular machines driven by light

2001

A series of compounds made up by linking methylnaphthalene fragments at both ends of different polyamine chains have shown to behave as pH-regulated molecular machines driven by light and fluorescence emission studies have proved the formation of an excimer between the two naphthalene units whose appearance, fluorescence intensity and decay times depend on the pH value of the media. Albelda Gimeno, Maria Teresa, Teresa.Albelda@uv.es ; Garcia-España Monsonis, Enrique, Enrique.Garcia-Es@uv.es ; Soriano Soto, Concepción, Concepcion.Soriano@uv.es

Highlights from the 42nd EUCHEM Conference on Stereochemistry, Bürgenstock, Switzerland, April 2007.

2007

Potassium Triggers a Reversible Specific Stiffness Transition of Polyethylene Glycol

2017

We use plasmon rulers made from two connected gold nanoparticles to monitor the conformation and stiffness of single PEG molecules and their response to cations. By observing equilibrium fluctuations of the interparticle distance, we obtain the spring constants or stiffness of the connecting single-molecule tether with pico-Newton sensitivity. We observe a transition of the PEG molecules’ extension and stiffness above about 1.2 mM K+ ion concentration which is specific to potassium ions. Molecular dynamics simulations reveal the formation of crown-like structures as the most likely molecular mechanism responsible for this specific effect.

Effects of side chains of oxatub[4]arene on its conformational interconversion, molecular recognition and macroscopic self-assembly.

2017

A series of oxatub[4]arenes with different alkyl side chains have been synthesized. The conformational interconversion, molecular recognition and macroscopic self-assembly behaviour of oxatub[4]arene derivatives were investigated. The difference in side chains slightly changes the binding affinities, but results in different self-assembly morphologies at the solid state.

Cu2+-Induced formation of cage-like compounds containing pyrazole macrocycles

2002

The crystal structure of the complex [Cu4(H22L)2(H2O)2- (ClO4)2](ClO4)2·2H2O where L is a new pyrazole ligand containing 1,5-diaminopentane spacers represents a new form of obtaining metal ion-induced inorganic–organic cages. Escarti Alemany, Francisco, franesa@alumni.uv.es ; Latorre Saborit, Julio, Julio.Latorre@uv.es ; Garcia-España Monsonis, Enrique, Enrique.Garcia-Es@uv.es