Does caffeine have any hydrogen bond donors?

Does caffeine have any hydrogen bond donors?

The covalent structure and atomic numbering of caffeine (1,3,7-trimethyl xanthine). With three of its four nitrogen atoms methylated, caffeine can only serve as a hydrogen bond acceptor, not as a conventional hydrogen bond donor (Figure 1).

Is there hydrogen bonding in caffeine?

In aqueous solution (around pH of 7), caffeine molecule is protonated (+ charge on nitrogen atoms) and therefore can interact with water via Hydrogen bonding and internally via dipole-dipole interactions and dipole-induced dipole interactions between positively charged N atoms and carbonyl O.

What is the donor in a hydrogen bond?

Hydrogen bond donor: A bond or molecule that supplies the hydrogen atom of a hydrogen bond. In this hydrogen bond between water and ammonia, water is the hydrogen bond donor (shown in red) and ammonia is the hydrogen bond acceptor.

How many hydrogen bond acceptors are in caffeine?

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Physico-chemical Properties

Is caffeine a ligand?

The target ligand, adenosine, is a large, polar molecule that binds to the extracellular binding domain of the A2A receptor by several nonpolar interactions. When caffeine binds to this receptor, it inhibits adenosine from binding to the extracellular binding domain of the A2A receptor.

Is caffeine an amine?

The two N atoms are part of amine groups. The C=C and C=N bonds look like functional groups, but they are neither alkene nor imine groups. They are both part of the 5-membered system called an imidazole ring. So caffeine contains two amine and two amide functional groups.

Is caffeine highly polar?

Yes, caffeine is a polar molecule. The Oxygen and Nitrogen molecules have a stronger polarity than Carbon, allowing them to slightly pull the electrons towards them in their covalent bond. This will give those atoms a slightly negative charge while giving the Carbon a positive charge.

Which is part of caffeine is a hydrogen bond acceptor?

While the overall structure of caffeine can be characterized as that of two fused, planar rings, because of its methyl groups, the molecule is not completely planar. With three of its four nitrogen atoms methylated, caffeine can only serve as a hydrogen bond acceptor, not as a conventional hydrogen bond donor ( Figure 1 ).

How is the aggregation of caffeine molecules observed?

As expected, extensive aggregation of the caffeine molecules was observed, with the molecules stacking their flat faces against one another like coins, with their methylene groups staggered to avoid steric clashes.

How is the structure of caffeine related to water?

Water was found to structure in a complex fashion around the planar caffeine molecules, which was not sensitive to the water model used.

What is the permanent electric dipole of caffeine?

It carries a permanent electric dipole of ∼3.6 – 3.7 D.6The flat faces of caffeine are sufficiently weakly hydrated such that it will easily separate out of water into non-polar liquids.