Planar Meso pentafluorophenyl core modified isophlorins

Article abstract of DOI:10.1021/ja710664y

Isophlorins and its analogues bridge the structural features between porphyrins and annulenes. Invariably they are known to be unstable but can be stabilized by appropriate substituents in the core and periphery of a macrocycle. Solid-state characterization of these 20π systems displays planarity for each macrocycle and even in their supramolecular arrangement due to C-H...F-C interactions. Copyright

Full text of DOI:10.1021/ja710664y

Supplementary Material for:
Planar Meso Pentafluorophenyl Core Modified Isophlorins
a
b
J. Sreedhar Reddy and Venkataramanarao G. Anand
Chemical Sciences &Technology Division,
National Institute for Interdisciplinary Science & Technology, NIIST (Formerly RRL)
CSIR, Trivandrum - 695019
India.
b
Indian Institute of Science Education & Research, (IISER)
9
00, NCL Innovation Park, Dr. Homi Bhabha Road,
Pune - 411 008, Fax: +91-20-25898022; Tel: +91-20-25898021,
E-mail: vg.anand@iiserpune.ac.in
India.
General notes and procedure:
1
H NMR spectra were recorded on a 300 MHz Bruker Advance DPX spectrometer.
Chemical shifts (δ) are reported in parts per million (ppm) relative to residual solvent
(
CHCl , s, δ, 7.26). Mass spectroscopic analysis of 1 was carried out on a Voyager-De-
3
STR (Applied Biosystems). Mass spectroscopic analysis of 2 was carried out on JEOL
JMS 600H spectrometer. Electronic spectra were recorded on a Perkin-Elmer Lambda 20
spectrophotometer. Chromatographic separations were performed on basic alumina and
silica gel (230-400) in glass columns.
Single Crystal Structure Determination: The single crystal X-ray diffraction data were
collected on a Bruker AXS Kappa Apex 2 CCD diffractometer at 173(2) K for 2 and
2
48(2) K for 1. Good quality single crystals were grown by slow evaporation of n-hexane
into chloroform solutions of 1 and 2.
Crystallographic data of 1: C H F O Mw = 980.01, Rhombohedral, space group R-3, a
4
4
8 20 4,
3
=
=
b = 19.8252(5) Å, c = 24.8223(9) Å, α =β = 90, γ =120, V = 8449.0(4) Å , Z = 9, D
1.734 g/cm , T = 248(2) K, R1 = 0.0359, R2 = 0.0877.
calc
-3
w
Crystallographic data of 2: C H F S O Mw = 1011.96, Tetragonal, space group I-4, a
4
4
8
20
2
2,
3
=
1
b = 12.1454(3) Å, c = 27.8101(16) Å, α =β = γ =90, V = 4102.3(3) Å , Z = 4, D
.795 g/cm , T = 173(2) K, R1 = 0.0593, R2 = 0.1938.
=
calc
-3
w
The water oxygen O2, in 2, and its four fold equivalents form a square shaped hydrogen
bonded cluster positioned around the four fold axis in the body center and at the unit cell
origin. Even though, the water hydrogens could not be located in the difference Fourier
map, O2-O2 # (#: 1-y, -1+x, z) distance of 2.809 Å shows strong hydrogen bonding
interaction between the water molecules. Further, the square water (O2) is bound to the
oxygens (O1) of the furan rings of four molecules generated by four fold rotation. The
O1-O2 distance of 3.037 Å shows a weak hydrogen bonding interaction.
S1

References:
Altormare, A., Gascarano, G., Giacovazzo, C., Guagliardi, A. (1993).
SIR92. J. Appl. Cryst. 26, 343-350.
Blessing, R. (1995). Acta Cryst. A51, 33-38.
Bruker-Nonius (2004). APEX-II and SAINT-Plus (Version 7.06a), Bruker
AXS Inc., Madison, Wisconsin, USA.
Bruker (1999). SADABS, Bruker AXS Inc., Madison, Wisconsin, USA.
Farrugia, L. J. (1999). WinGX. J. Appl. Cryst. 32, 837-838
Frrugia, L. J. (1997). ORTEP3 for windows. J. Appl. Cryst. 30, 565.
Sheldrick, G. M. (1997). SHELXL97. University of G\"ottingen, Germany.
Spek, A. L. (1990) Acta Cryst. A46, C34
Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.
S2

Scheme
R
R
R
R
R
R
R
R
O
O
S
O
+
a, b
a, b
R
O
O
O
O
HO
R
OH
R
O
S
2
S
HO
3
4
1
R = C6F5
Synthetic procedure for 1: 2-pentafluorophenylhydroxy methyl furan (264 mg, 1
mmol), 3, in 100 ml of dry CH Cl was degassed with argon for 10 min, then BF .OEt
2
2
2
3
(0.12 ml, 1 mmol) was added under dark, and the resulting solution was stirred for 2h.
After adding five equivalents of FeCl , solution was opened to air and stirred for
3
additional two hours. The reaction mixture was washed with water and passed through a
short alumina column. This mixture was separated by repeated silica gel column
chromatography by using CH Cl /n-hexane as eluant. A green color band obtained was
2
2
identified as 1 in 2.5% yields (7 mg).
1
H NMR (300MHz, CDCl , 298K): δ = 2.49 (s, 8H); UV-Vis (CH Cl ): λ (ε) = 320
3
2
2
max
(
22,121), 357 (30,654), 409 (331), 434 (378), 463 (370), 498 (275); MALDI-TOF Mass
+
m/z: Calcd. For C H F O : 980.01; Observed: 980.55(100.0%, M ).
4
4
8
20
4
Synthetic procedure for 2: A similar procedure as mentioned for 1 was followed with
,5-bis(pentafluorophenylhydroxymethyl) thiophene, 4, (476 mg, 1 mmol) and furan
0.072 ml, 1 mmol). 2 was obtained in 6% yields (15 mg).
2
(
1
H NMR (300MHz, CDCl , 298K): δ = 3.33 (s, 4H), 3.37 (s, 4H); UV-Vis (CH Cl ):
3
2
2
λmax(ε) = 344 (30,996), 376 (46,333), 409 (336), 437 (369), 465 (313), 497 (159); FAB
+
Mass m/z: Calcd. For C H F S O : 1011.96; Observed: 1012.27 (100.0%, M ).
44
8
20
2
2
2
-(pentafluorophenylhydroxymethyl) furan (3): To a stirred solution of freshly
o
distilled furfural [10mmol, 0.83ml in 40 ml THF] under argon atmosphere at 0 C, freshly
prepared Grignard Reagent [C F MgBr, (12.5mmol)] was added. Stirring was allowed
6
5
for 2 hours to attain room temperature and the reaction mixture was quenched with
saturated NH Cl solution. The organic layer was extracted with Et O (50 ml) three times
4
2
and combined organic layers was washed with water and brine solution. After drying
over Na SO , the solvent was removed under vacuum and purified through silica gel(100-
2
4
2
00 mesh) column chromatography with CH Cl :n-Hexane (1:3) as eluant, to yield the
2 2
pure compound as light yellow solid.( 2.0 grams Yield: 76%.)
1
H NMR: (400MHz, CDCl 298K): δ = 7.4 (s, 1H), 6.37(m, 1H), 6.30(d, J= 4.0Hz, 1H),
.16(d, J=11.2Hz 1H), 2.79 (d, J=11.2Hz, 1H). EI MS m/z: 264.08(100.0%, M )
3,
+
6
S3

Electronic Absorption Studies:
-5
Electronic absorption spectra of 10 M solutions of 1 and 2 in dichloromethane.
Titration with HClO4:
Changes in Electronic Absorption Spectrum upon addition of HClO to 1 (left) and 2
4
(right)
S4

Solvent
H O
2
1
H NMR Spectrum of 1 at 298K
S5

Solvent
X
H O
2
1
H NMR Spectrum of 2 at 298K
S6

MALDI-TOF Mass spectrum of 2 and 1
S7

o
Two molecules of 1 interact through two C3-H3…F2 (2.5 Ǻ, 115 ) hydrogen bonds.
Other meso aryl groups are omitted for clarity.
One dimensional hydrogen bonded chain of 1 through C-H…F hydrogen bonding.
Other meso aryl groups are omitted for clarit
S8

Cyclic hexamer of 1 formed due to six C-H…π( pink dotted line) along with three F…F
interactions (cyan dotted lines). Other meso aryl groups are omitted for clarity.
S9

o
Two molecules of 2 interact through two C4-H4…F3 (2.68 Ǻ, 170.5 ) hydrogen bonds.
Two dimensional supramlolecular grid of 2 formed due to C-H…F hydrogen bonding.
S10