Redox Properties of 2-[(R-Phenyl)amine]-1,4-naphthalenediones
J . Org. Chem., Vol. 64, No. 10, 1999 3693
2-[(4′-n -Bu tylp h en yl)a m in e]-1,4-n a p h th a len ed ion e (p-
Bu P AN). Recrystallization from ethanol gave 61% yield; mp
112-114 °C; IR (KBr, cm-1) 3284, 2922, 1680, 1590, 1566; UV-
for C16H10O4N2. Calcd. 294.0655, found 294.0641. Anal. Calcd
for C16H10O4N2: C, 65.30; H, 3.40; N, 9.52. Found: C, 65.01;
H, 3.27; N, 9.43.
1
vis (EtOH, nm) 272 (30400), 472 (4700); H NMR (CDCl3) δ
Electr och em ica l P r oced u r e. Solven t a n d Su p p or tin g
Electr olyte. Acetonitrile (AN) (Aldrich) was dried overnight
with CaCl2 (Merck) and purified by distillation on P2O5 (Merck)
under vacuum.31 Traces of water in the solvent were elimi-
nated by contact with a molecular sieve 3 Å (Merck) in the
absence of light. Tetraethylammonium tetrafluoroborate (Et4-
NBF4) (Fluka) was dried under vacuum at 60 °C.
8.10 (dt, 2H, J ) 7.5, J ) 1.4 Hz, H5, H8), 7.78 (td, 1H, J )
7.5, J ) 1.4 Hz, H7), 7.65 (td, 1H, J ) 7.5, J ) 1.4 Hz, H6),
7.52 (sb,1H, NH), 7.21 (m, 4H, H2′, H3′, H5′, H6′), 6.37 (s, 1H,
H3), 2.67 (t, 2H, J ) 7 Hz, CH2), 1.60 (q, 2H, J ) 7 Hz, CH2),
1.35 (q, 2H, J ) 7 Hz, CH2), 1.25 (t, 3H, J ) 7 Hz, CH3); 13C
NMR (CDCl3) δ 183.75 (C4), 182.13 (C1), 145.08 (C2), 140.71
(C1′), 134.97 (C4′), 134.38 (C6), 133.38 (C10), 132.17 (C7), 130.46
(C9), 129.59 (C2′, C6′), 126.42 (C5), 126.13 (C8), 122.75 (C3′, C5′),
103.11 (C3), 35.08 (C7′), 33.47 (C8′), 22.24 (C9′), 13.85, (C10);
CIMS m/z 305, 277, 262, 248, 235, 204, 178, 116, 89, 77, 57,
43. Anal. Calcd for C20H19O2N: C, 78.68; H, 6.22; N, 4.59.
Found: C, 78.64; H, 6.21; N, 4.48.
Electr od es, Ap p a r a tu s, a n d In str u m en ta tion . Cyclic
voltammetry measurements were carried out in a conventional
three-electrode cell. A polished Pt-disk electrode with an area
of 3.14 mm2 was used as a working electrode. Prior to
measurements, this electrode was cleaned and polished with
0.05 µm alumina (Buehler), wiped with a tissue, and sonicated
in distilled water for 2-4 min. The counter electrode consisted
of a piece of platinum wire. The reference electrode was an
aqueous saturated calomel electrode (SCE) isolated from the
main cell body by a Luggin tube filled with 0.1 M Et4NBF4/
acetonitrile.
2-[(4′-n -Hexylp h en yl)a m in e]-1,4-n a p h th a len ed ion e (p-
HexP ANQ). Recrystallization from ethanol gave 62% yield;
mp 100-101 °C; IR (KBr, cm-1) 3450, 3274, 2922, 1690, 1620,
1596, 1568, 1516, 1412; UV-vis (EtOH, nm) 272 (33600), 474
1
(5500); H NMR (CDCl3) δ 8.00 (dt, J ) 7.5 Hz, H5), 7.72 (td,
1H, H8), 7.6 (td, J ) 7.5, J ) 1.4 Hz, H7), 7.43 (td, J ) 7.5, J
) 1.4 Hz, H6), 7.25 (m, 4H, H2′,H3′,H5′,H6′), 6.41 (s, 1H, H3),
2.61(t, 2H, J ) 7 Hz, CH2), 1.62 (m, 4H, 2CH2), 1.39 (m, 4H,
2CH2), 1.28 (t, 3H, J ) 7 Hz, CH3); CIMS m/z 333, 262, 248,
235, 178, 116, 105, 89, 77, 43. Anal. Calcd for C22H22O2N: C,
79.27; H, 6.90; N, 4.20. Found: C, 79.02; H, 7.00; N, 4.15.
The half-wave potentials were measured at room temper-
ature in acetonitrile solutions using 0.1 M Et4NBF4 as the
supporting electrolyte. The concentration for the PAN solutions
varied from 0.2 mM to 1.0 mM, depending on their solubility
in the solvent. Voltammetric curves were recorded using a BAS
100B/W Electrochemical Analyzer of Bioanalytical Systems
interfaced with a Gateway 2000 personal computer. Measure-
ments were made over a potential range between 500 to -2000
mV with a sweep rate from 10 to 8000 mV/s. Prior to the
experiments, solutions were purged with nitrogen, which was
presaturated with the appropriate solvent containing 3 Å
sieves. All potentials were determined under the same condi-
tions in order to obtain a consistent data set. To establish a
reference system with the experimental conditions of our
particular system, the redox potentials reported in this paper
refer to the ferrocene/ferrocinium (Fc/Fc+) pair, as recom-
mended by IUPAC.32 In this case the potential for the
ferrocene/ferrocinium (Fc/Fc+) redox pair, determined by vol-
tamperometric studies, was 399 mV vs SCE.
2-[(3′-F lu or op h en yl)a m in e]-1,4-n a p h th a len ed ion e (m -
F P AN). Recrystallization from ethanol gave 53% yield; mp
196-198 °C; IR (KBr, cm-1) 3448, 3316, 3074, 1666, 1640,
1590; UV-vis (EtOH, nm) 276, 456; 1H NMR (CDCl3) δ 8.1
(dt, 2H, J ) 7.5, J ) 1.4 Hz, H5, H8), 7.77 (td, 1H, J ) 7.5, J
) 1.4 Hz, H6), 7.67 (td, 1H, J ) 7.5, J ) 1.4 Hz, H7), 7.59 (sb,
1H, NH), 7.40 (td, 1H, J ) 7.5, J ) 1.4 Hz, H5′), 7.08 (sb, 1H,
H2′), 7.06 (dt,1H, J ) 7.5, J ) 1.4 Hz, H4′), 6.91 (td, 1H, J )
7.5, J ) 1.4 Hz, H6′), 6.46 (s, 1H, H3); 13C NMR (CDCl3) δ
183.91 (C4), 181.76 (C1), 160.00 (C3′), 144.10 (C2), 137.65 (C1′),
134.99 (C7), 132.50 (C6), 130.85 (C5′), 127.06 (C9), 126.58 (C8),
126.20 (C5), 117.88 (C2′) 112.51 (C6′), 109.78 (C4′), 104.27 (C3);
CIMS m/z 267, 266, 239, 238, 222, 211, 185, 183, 162, 149,
129, 105, 83, 69, 57, 55, 43, 41. HRMS for C16H10O2NF calcd
267.0696, found 267.0702. Anal. Calcd for C16H10O2NF: C,
71.91; H, 3.74; N, 5.24. Found: C, 71.69; H, 3.74; N, 5.24.
2-[(3′-Cya n op h en yl)a m in e]-1,4-n a p h th a len ed ion e (m -
CNP AN). Recrystallization from acetonitrile gave 34% yield;
mp 296-298 °C; IR (KBr, cm-1) 3306, 3182, 3070, 2226, 1676,
1601, 1575; UV-vis (EtOH, nm) 273, 448; CIMS m/z 274, 257,
246, 245, 229, 218, 190, 169, 146, 105, 104, 77, 76, 57, 43, 41.
HRMS for C16H10O2N2 calcd 274.0745, found 274.0742. Anal.
Calcd for C16H10O2N2: C, 74.45; H, 3.64; N, 10.21. Found: C,
74.12; H, 4.02; N, 9.83.
2-[(4′-(Tr iflu or om et h yl)p h en yl)a m in e]-1,4-n a p h t h a -
len ed ion e (p-CF 3P AN). Recrystallization from acetonitrile
gave 87% yield; mp 185-186 °C; IR (KBr cm-1) 3440, 3234,
3072, 1676, 1634, 1622, 1600, 1574, 1528; UV-vis (EtOH, nm)
271 (35460), 452 (5160) 1H NMR (CDCl3) δ 8.16 (dt,1H, H5 or
H8), 8.11 (dt,1H, H8 or H5), 7.80 (td, 1H, J ) 7.5, J ) 1.4 Hz,
H7), 7.69 (td, 1H, J ) 7.5, J ) 1.4 Hz, H6), 7.65 (bs, 1H, NH),
7.51 (vbs, 4H, H2′, H3′, H5′, H6′), 6.43 (s, 1H, H3); 13C NMR
(CDCl3) δ 183.90 (C4), 181.70 (C1), 144.25 (C2), 138.30 (C1′),
135.07 (C7), 133.04 (C10), 132.62 (C9), 132.04 (C6), 130.37 (C3′),
126.66 (C8), 126.31 (C4′, C5), 125.48 (C5′), 122.08 (C2′), 119.24
(C6′), 104.23 (C3), 104.06 (C7′); CIMS m/z 317, 300, 298, 296;
288, 272, 248, 241, 220, 212, 146, 145, 105, 76, 69, 57, 43, 41.
HRMS for C17H9O2NF3 calcd 317.0664, found 317.0661. Anal.
Calcd for C17H9O2NF3: C, 64.15; H, 3.15; N, 4.41. Found: C,
63.87; H, 3.09; N, 4.36.
Com p u ta tion a l Meth od s. Full geometry optimization
(without symmetry constraints) on the complete structures of
p-MeOPAN, p-MePAN, PAN, p-FPAN, p-CF3PAN, p-CNPAN,
p-NO2PAN, and naphthoquinone (NQ) were performed at the
PM3 level (Table 3) and according to the DFT at Becke3LYP/
6-31G(d,p) level (Table 4) with the Gaussian 92 Program
(G92).33 The Becke3LYP hybrid functional defines the ex-
change function as a linear combination of Hartree-Fock,
local, and gradient-corrected exchange terms.34 The exchange
function is combined with a local and gradient-corrected
correlation function. Substituent groups at the para-position
in the aniline group were chosen in order to avoid conforma-
tional difficulties.
The correlation function used is actually C*ECLYP + (1-C)-
*ECVWN, were LYP is the correlation functional of Lee, Yang,
and Parr,35 and includes both local and nonlocal terms. VWN
is the Vosko, Wilk, and Nusair 1980 correlation functional
fitting the RPA solution to the uniform gas, often referred to
(30) Pratt, Y. T. J . Org. Chem. 1962, 27, 3905-3910.
(31) Coetzee, J . F.; Cunningham, D. K.; Mc. Guire, D. K.; Pad-
manabban, A. Anal. Chem. 1962, 34, 1139-1143.
(32) Gritzner, G. and Ku¨ta, J . Pure Appl. Chem. 1984, 4, 462-466.
(33) G92: Gaussian 92/DFT, Revision G.2. Frisch, M. J .; Trucks,
G. W.; Schlegel, H. B.; Gill, P. M. W.; J ohnson, B. G.; Wong, M. W.;
Foresman, J . B.; Robb, M. A.; Head-Gordon, M.; Replogle, E. S.;
Gomperts, R.; Andres, J . L.; Raghavachari, K.; Binkley, J . S.; Gonza´lez,
C.; Martin, R. L.; Fox, D. J .; Defrees, D. J .; Baker, J .; Stewart, J . J . P.;
Pople, J . A. Gaussian, Inc., Pittsburgh, PA, 1993.
(34) Stephens, P. J .; Devlin, F. J .; Chabalowski, C. F.; Frisch, M. J .
J . Phys. Chem. 1994, 98, 11623-11627. Becke, A. D. J . Chem. Phys.
1993, 98, 1372-1377, 5648-5652.
(35) Lee, C.; Yang, W.; Parr, R. G. Phys. Rev. 1988, B37, 785-789.
Miehlich, B.; Savin, A. Stoll, H.; Preuss, H. Chem. Phys. Lett. 1989,
157, 200-206.
2-[(3′-Nit r op h en yl)a m in e]-1,4-n a p h t h a len ed ion e (m -
NO2P AN). Recrystallization from acetonitrile gave 50% yield;
mp 258-260 °C; IR (KBr, cm-1) 3442, 3288, 3214, 3074, 1676,
1604, 1576, 1528, 1352; UV-vis (EtOH, nm) 271 (23600), 447
1
(4000); H NMR (DMSO) δ 8.25 (bs, 1H, NH), 7.7 to 8.1 (m,
8H, aromatics), 6.3 (s, 1H, H3); CIMS m/z 294, 277, 265, 248,
247, 219, 191, 189, 165, 146, 129, 105, 76, 57, 43, 41. HRMS