L. Jaquinod et al., A NOVEL SERIES OF STRAPPED PORPHYRINS - COMPARISON OF THE MOLECULAR-STRUCTURES OF 4 2,2'-SUBSTITUTED BIPHENYL STRAPPED MESO-DIPHENYLPORPHYRINS, New journal of chemistry, 19(4), 1995, pp. 453-460
The crystal and molecular structures of four metal-free 2,2'-disubstit
uted biphenyl strapped diphenylporphyrins are reported. The 2,2'-subst
ituents of the biphenyl straps are nitro (1a), ethoxy, (1b), methyl (2
a) and methoxy (2b) groups. The covalent links between the 3,3'-positi
ons of the biphenyl straps and the o-positions of the meso-phenyl ring
s of the diphenylporphyrins are amido (-C(O)-NH-) groups in 1a and 1b,
and ether (-CH2 - O-) moieties in 2a and 2b. In all these strapped po
rphyrins, the 2,2'-substituents are oriented toward the porphyrin core
s and are in Van-der-Waals contact with each other and with porphyrin-
core atoms. The heights of the cavities lying between the straps and t
he mean planes in the porphyrin have similar values in 1a and 1b, and
in 2a and 2b, the corresponding mean values being 5.207(5) Angstrom (1
a, 1b) and 5.293(4) Angstrom (2a, 2b). These figures indicate that in
the metal-free porphyrins the amido or ether links introduce similar c
avity heights. Strong hydrogen bonds occur in Ib between the NH groups
of the amido links and the oxygen atoms of the 2,2'-ethoxy substituen
ts of the strap. Crystal data: \[NHCO - (2,2'-(NO2)(2) - BPh) - COHN]
H2DPP\. 3CHCl(3) (H2DPP=5,15-diphenylporphyrin) (1a . 3CHCl(3)), tricl
inic, P ($) over bar 1, a=15.529 (4), b=14.096 (4), c=12.740 (3) Angst
rom, alpha=105.98 (2), beta=99.57 (2), gamma=102.21 (2)degrees, Z=2; \
[NHCO - (2,2'-(OC2H5)(2)-BPh) - NHCO] H2DPP\. CHCl3 (1b . CHCl3), tric
linic P ($) over bar 1, a=13.811(4), b=15761(5), c=10.258(3) Angstrom,
alpha=98.11(2), beta=97.86(2), gamma=98.28(2 degrees), Z=2; \[OCH2-(2
,2'-(CH3)(2) -BPh)-CH2O]H2DPP\ (2a), triclinic, P ($) over bar 1, a=13
.545(4), b=14.511(4), c=12.488(3) Angstrom, alpha=114.43 (2), beta=99.
52 (2), gamma=115.84 (2)degrees, Z=2; and \[OCH2 - (2,2'-(OCH3)(2) - B
Ph) - CH2O] Etio(II) - H2DPP\ (2b) (Etio(II)-H2DPP=2, 8, 12, 13-tetrae
thyl-3, 7, 13, 17-tetramethyl-5, 15-diphenylporphyrin), triclinic, P (
$) over bar 1, a=14.559(4), b=14.669(4), c=12.459(3) Angstrom, alpha=9
4.96(2), beta=103.48(2), gamma=107.95 (2)degrees, Z=2.