Sentences with phrase «hydrogen bonds in»

DNA (DeoxyriboNucleic Acid) a molecule composed of two chains of nucleic acid bases held together by hydrogen bonds in a pattern resembling a flexible twisted ladder.

Trinuclear copper - oxo clusters were identified that exhibit a high reactivity towards activation of carbon — hydrogen bonds in methane and its subsequent transformation to methanol.

Previous research had overlooked these collective interactions among carbon - hydrogen bonds in organic crystals, Dinh said.

Their analysis suggests that the carbon - hydrogen bonds in DEB play a key role in the molecule's volatile behavior.

Now, researchers have explored how and why this volatility varies during hydrogenation, suggesting that a previously underappreciated effect from carbon - hydrogen bonds in the molecule is the main culprit.

When carbon dioxide gas entered the mix, the gas molecules broke hydrogen bonds in the water molecules, making the ice more brittle.

The gas molecules seemed drawn to the tip of the crack; to get there, they flipped along the surface like zombie gymnasts, leaving broken hydrogen bonds in their wake.

Trinuclear copper - oxo clusters were identified that exhibit a high reactivity towards activation of carbon - hydrogen bonds in methane and its subsequent transformation to methanol.

They proved that the weak hydrogen bonds in water partially get their identity from stronger covalent bonds in the H2O molecule.

Herein we demonstrate that a photoredox - mediated hydrogen atom transfer protocol can efficiently and selectively install deuterium (D) and tritium (T) at α - amino sp3 carbon - hydrogen bonds in a single step, using isotopically labeled water (D2O or T2O) as the source of hydrogen isotope.

In the double - helix configuration, two strands of DNA are joined to each other by hydrogen bonds in an arrangement known as base pairing.

The rays do this by causing molecules in the ring known as amide groups to shuffle from opposite sides of the carbon bond to the same side, loosening hydrogen bonds in the process.

When the experiment was repeated using propanol — a larger alcohol with less hydrogen bonding in the mixture — optical distillation produced the same result as thermal distillation.

The isomers differ in the position of a nitrogen - hydrogen bond in respect to the nickel center.

The catalyst splits the hydrogen - hydrogen bond in H2 to produce protons at room temperature.

His books on crystal engineering (Elsevier, 1989) and the weak hydrogen bond in structural chemistry and biology (OUP, 1999) are particularly well known.

Not exact matches

Their composition is largely dependent on hydrogen atoms in the molecules, and the ability of these to create hydrogen bonds with other elements.

The diamond - like structural unit consists of six - sided rings of carbon atoms bonded together in chains surrounded by a halo of hydrogen atoms.

They are called saturated because hydrogens fill all the bonds in the carbons, soaking the molecule in hydrogen.

But when the music stops, the hydrogens go back to bind again to the carbons, and they don't always come down in the same positions on the remaining double bonds.

In principle, the wave function, denoted by Greek letter psi, can be used to reveal these energy levels for any given atom or molecule, although in practice this has only been done for the very simplest — the hydrogen atom and molecule (made of two hydrogen atoms bonded togetherIn principle, the wave function, denoted by Greek letter psi, can be used to reveal these energy levels for any given atom or molecule, although in practice this has only been done for the very simplest — the hydrogen atom and molecule (made of two hydrogen atoms bonded togetherin practice this has only been done for the very simplest — the hydrogen atom and molecule (made of two hydrogen atoms bonded together).

Another major advantage the catalysts have is that, while they are general in what substrate they can oxidize, they are very specific about which carbon - hydrogen bonds they cut — so much so that they target a certain spot on amino acids like proline, leucine or valine even when they are part of a much larger peptide chain.

Hydrogen atoms contained in water readily bond with the heavy isotope to form hydrochloric acid gas, which then leaks into space — leaving more of the lighter isotope behind.

When the team applied the technique to a sample of the organic molecule PTCDA, not only did the molecules show up in intricate detail, an electrical signal was also detected between them (coloured green below), at exactly the locations where hydrogen bonds are present (Journal of the American Chemical Society, DOI: 10.1021 / ja104332t).

Weaker hydrogen bonds enable the ring in the structure on the right to spin up to a million times faster than in the structure on the left.

At this temperature, the pressure in the reactor reaches 34 atmospheres, helping to break down the bonds between the hydrogen and carbon atoms in the polymer chains.

Complex organic molecules, consisting of carbon bonded with other elements like oxygen and hydrogen, are common in the Milky Way, but it was uncertain whether they would be produced in certain dwarf galaxies like the neighboring Large Magellanic Cloud.

Free radicals attack weak carbon - hydrogen bonds and are a major source of the kind of oxidative cell damage that can occur in conditions such as coronary artery disease, neurological disorders and retinal ailments.

In aqueous fluids, amino acid residues that have polar sidechains — components that can have a charge under certain physiological conditions or that participate in hydrogen bonding — tend to be located on the surface of the protein where they can interact with water, which has negatively and positively side charges to its moleculIn aqueous fluids, amino acid residues that have polar sidechains — components that can have a charge under certain physiological conditions or that participate in hydrogen bonding — tend to be located on the surface of the protein where they can interact with water, which has negatively and positively side charges to its moleculin hydrogen bonding — tend to be located on the surface of the protein where they can interact with water, which has negatively and positively side charges to its molecule.

The zirconium sapped the loyalty of the electrons bonding the nitrogen pairs, weakening the link between the two atoms and letting hydrogen weasel in and latch onto the nitrogen.

He has spent his career focused on just one bond, a link between a carbon and a hydrogen atom in a molecule of methane, the main component of natural gas.

They make good fuels because the energy stored in the bonds between carbon and hydrogen is abundant and easy to release in combustion with oxygen.

First, the chemists release the hydrogen from its bonds with carbon by mixing methane with oxygen, throwing in a catalyst, and turning up the heat.

«That's what his advance is pointing towards,» he says, «finding an alternative catalyst that will allow us to do oxygen evolution (breaking the bonds of water or H2O and forming oxygen) in concert with hydrogen» on a grand scale.

In recent years researchers have achieved better performance with compounds such as lithium borohydride, in which the metal atoms form weaker, ionic bonds with groups containing several hydrogen atomIn recent years researchers have achieved better performance with compounds such as lithium borohydride, in which the metal atoms form weaker, ionic bonds with groups containing several hydrogen atomin which the metal atoms form weaker, ionic bonds with groups containing several hydrogen atoms.

Water molecules move through the viscous supercooled water in jumps related to hydrogen bond breaking.

It turned out that the negative compressibility of sodium amidoborane crystals has to be a consequence of the elongation of the chemical bonds between nitrogen and hydrogen and boron and nitrogen, caused by the abrupt formation of new hydrogen bonds between adjacent molecules in the crystal.

These weak interactions, such as hydrogen bonds, van der Waals forces, and π - π interactions, govern the assembly of everything from DNA in its famous double helix to the bonding of H2O molecules in liquid water.

It's important to have the right ligand, the right amount of hydrogen peroxide, and the right metal in order to oxidize these challenging C - H bonds.

Water molecules in the solid state, such as in ice and snow, form weak bonds (called hydrogen bonds) to one another.

Atoms of most elements, such as hydrogen, oxygen and carbon, form tight chemical bonds by sharing electrons with their neighbours in order to give each atom a stable configuration of electrons.

The researchers discovered that these catalysts — copper in the form of a white salt and the ligand as an oil — can oxidize C - H bonds in a very efficient way in combination with hydrogen peroxide, a reduced form of oxygen that nature uses.

DNA sequence discrimination by CAP derives both from sequence - dependent distortion of the DNA helix and from direct hydrogen - bonding interactions between three protein side chains and the exposed edges of three base pairs in the major groove of the DNA.

In a hair strand, the keratin molecules are mainly held together by two forces: chemical cross-links between cysteines (a type of amino acid) and weaker hydrogen bonds.

The hydrogen bonds can be disrupted by water vapor in the air, with each keratin binding to water in the air instead of each other.

The amalgamation of these techniques provided a fully characterized structure, one in which the dissolved carbon dioxide acts as a hydrophobe, having formed only very weak hydrogen bonds to the surrounding water molecules.

For example, in water (H2O) the sole oxygen atom is bound to two hydrogen atoms, and the two bonds constantly change in length.

In order to obtain new compounds, it is necessary to break the bond of carbon and hydrogen to form carbon - carbon bond,» explains the researcher.

«Hydrocarbons — compounds made out of carbon and hydrogen or having a carbon - hydrogen bond — are used in daily life all the time — from clothes to toothbrushes,» said Partha Basu, chair and professor of chemistry and biological chemistry at IUPUI.

When ethanol dissolves in water, the ethanol molecules remain intact but form new hydrogen bonds with the water.