dipole moment of pyrrole and furan
Q. compare the dipole moment of pyrrole and
furan ?
Oxygen is more electronegative than nitrogen.
Consequently the lone pair on O-atom
is more tightly held and so is less available for preserving the aromatic character of furan.
But lone pair on N-atom is more available for preserving the aromatic character of pyrrole ring.
As a result, the resultant dipole moment of pyrrole acts towards the ring.
But the dipole moment of furan is opposite to that of pyrrole, because oxygen atom of furan contains two lone pair of electrons.
One lone pair is involved for preserving aromatic character of ring and another lone pair acts in opposite direction of ring.
Thus , the actual dipole moment acts in furan is opposite towards the ring, that is, furan and pyrrole have opposite direction of the dipole moment.
is more tightly held and so is less available for preserving the aromatic character of furan.
But lone pair on N-atom is more available for preserving the aromatic character of pyrrole ring.
As a result, the resultant dipole moment of pyrrole acts towards the ring.
But the dipole moment of furan is opposite to that of pyrrole, because oxygen atom of furan contains two lone pair of electrons.
One lone pair is involved for preserving aromatic character of ring and another lone pair acts in opposite direction of ring.
Thus , the actual dipole moment acts in furan is opposite towards the ring, that is, furan and pyrrole have opposite direction of the dipole moment.
The resonating structure of pyrrole and furan are
given below.
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