Hydrogen BondingSWBAT: Draw hydrogen bonds between two molecules
Definition Hydrogen Bond A hydrogen bond is an electromagnetic attraction -
not a true bond! Hydogen must be directly bonded to a small atom
with high EN (N, O, F) Can form with another molecule (intermolecular) or
another part of the same molecule (intramolecular). The hydrogen has a partial δ+ charge and the oxygen
has a partial δ- charge from being covalently bonded to an electronegative atom
Symbol Covalent bond: solid line H-bond: dotted line
Intermolecular H Bonding Hydrogen bonding between two
molecules – from the attraction of the dipoles
Intramolecular H-bonding DNA Hydrogen bonding within its own molecule
– from the attraction of the dipoles
Intra…..3D- Structure of Proteins
Intra…..3D- Structure of Proteins
Hydrogen Bonding
Important H-bonds do not have to involve water
molecules! All it needs is a δ+ H which can come from
any molecule: SH2, C-OH, COOH, DNA, proteins….
And a δ- element as a neighbor (usually its O, S, N, P or the Halogen group)
Organic molecules and H-bonds Draw dipole and partial charges of the
following functional groups: don’t forget the unpaired Valence e- of Oxygen
COH Alcohol CHO Aldehyde CO Ketone COOH Acid
H-Bond Drawing guide Oppose each δ+ and δ- with one H2O Show the δ+ and δ- and net dipole of
each water molecule Draw H-bonds as dotted linesPractice: CH3COH •3H2O CH3CH2 COOH •4H2O CH2O •2H2O