Rhodium(III) 22-(μ-ethylidene)-m-benziporphyrin 73-Rh also undergoes the
contraction of m-phenylene, giving a mixture of 21-(μ-ethylidene)-21carbaporphyrins 85-Rh, 86-Rh, and 87-Rh (Scheme 47). They contain the
rhodacyclopropane motif substituted by a methyl group [25].
Fig. 6 X-ray-determined molecular crystal structure of 81-Rh. Adapted from Ref. [23]
N
N
N
Ph
Ph
Ar
Ar
Rh
CHO
N
N
N
Ph
Ph
Ar
Ar
Rh
CHO
N
N
N
Ph
Ph
Ar
Ar
Rh
OHC
CHO
CHO
H
H
H
N
N
N
Ph
Ph
Ar
Ar
Rh
CHO
+
5-Rh(CO)
74-Rh
Al 2 O 3, CH 2 Cl 2
81-Rh
82-Rh
83-Rh
N
N
N
Ph
Ph
Tol
Tol
Rh
CO
Cl
CH 2 Cl 2
Scheme 45 Contraction of rhodium(III) m-benziporphyrin 5-(RhCO) to rhodium(III)
21-carbaporphyrins 81-Rh, 82-Rh, and 83-Rh
A Pincer Motif Etched into a meta-Benziporphyrin Frame
215