Synthesis and Properties of a New Molecular Electron Donor
coal was added, and the solution was stirred for 10 min before be-
ing filtered through silica. After removal of the solvent in vacuo a
green-yellow solid remained, which was redissolved in CH2Cl2. Yel-
low needles of [6H2](PF6)2 (0.017 g, 0.021 mmol, 42%) precipitated
from a solution of CH2Cl2/Et2O (1:1). 1H NMR (399.89 MHz,
CD2Cl2): δ = 6.11 (s, 2 H), 2.78 (s, 48 H, CH3) ppm. 13C NMR
(100.56 MHz, CD2Cl2): δ = 40.24 (CH3) ppm. MS (FAB): m/z (%)
= 676 (43) [(ttmgb)(H)2(PF6)]+, 531 (100) [(ttmgb)(H)]+, 486 (40)
Experimental Section
General: All synthetic work was carried out by using standard
Schlenk techniques. UV/Vis spectra were recorded with a Perkin–
Elmer Lambda spectrometer. An EG&G Princeton 273 apparatus
was used for the CV measurements. IR spectra were taken with the
help of a BIORAD Excalibur FTS 3000 spectrometer. NMR spec-
tra were measured with a Bruker Avance II 400 spectrometer.
[(ttmgb
– N(CH3)2]. Crystal data for [6H2](PF6)2·1.5H2O:
6: To a solution of N,N,NЈ,NЈ-tetramethylurea (1.1 mL, 9.4 mmol)
dissolved in dry CHCl3 (6 mL) was added oxalyl chloride (4 mL,
46.5 mmol, 4.9 equiv.) dropwise. The reaction mixture was stirred
for 16 h under reflux. Then, the solvent was removed in vacuo. The
remaining solid, 2-chloro-1,1Ј,3,3Ј-tetramethylformamidium chlo-
ride, was washed with Et2O, dissolved in CH3CN (24 mL) and
added slowly and dropwise to a CH3CN solution (10 mL) contain-
ing 1,2,4,5-tetraaminobenzene (0.5 g, 1.8 mmol) and triethylamine
(3.4 mL, 24.6 mmol) at a temperature of 0 °C. Subsequently, the
mixture was stirred for an additional period of 1 h at 0 °C. The
precipitate was filtered before being redissolved in HCl (10%). Af-
ter addition of NaOH (20%), the solution was extracted with tolu-
ene (3ϫ). The combined toluene phase was dried with K2CO3, and
toluene was removed under vacuum to afford ttmgb (0.5683 g,
1.1 mmol, 61%) as a pale yellow-white solid. Upon recrystallisation
from CH3CN colourless crystals of ttmgb were obtained. 1H NMR
(199.92 MHz, CD3CN): δ = 5.54 (s, 2 H), 2.63 (s, 48 H, CH3) ppm.
1H NMR (399.89 MHz, C6D6): δ = 6.26 (s, 2 H), 2.66 (s, 48 H,
CH3) ppm. 13C NMR (50.28 MHz, CD3CN): δ = 158.27, 138.08,
115.58 (CH), 39.78 (CH3) ppm. 13C NMR (100.56 MHz, C6D6): δ
C26H52N12P2F12·1.5H2O, Mr = 848.75, 0.40ϫ0.25ϫ0.25 mm3,
monoclinic, space group P21/n, a = 7.8380(16) Å, b = 21.349(4) Å,
c = 12.478(3) Å, β = 105.90(3)°, V = 2008.1(7) Å3, Z = 2, dcalcd.
= 1.400 Mgm–3, Mo-Kα radiation (graphite monochromated, λ =
0.71073 Å), T = 200 K, θrange 1.95 to 27.50°. Reflections measured
64704, independent 4526, Rint = 0.0426. Final R indices [IϾ2σ(I)]:
R1 = 0.0689, wR2 = 0.1801 ppm.
6(I3)2: To a solution of 6 (0.0314 g, 0.06 mmol) in CH3CN (20 mL)
was added I2 (0.0313 g, 0.12 mmol). The solution turned deep-
green in colour, from which purple-black crystals of 6(I3)2
(0.0126 g, 0.01 mmol, 17%) of a metal appearance precipitated. 1H
NMR (200.13 MHz, CD3CN): δ = 5.17 (s, 2 H), 2.88 (s, 48 H,
CH3) ppm. 13C NMR (100.56 MHz, CD3CN): δ = 41.00 (CH3)
ppm. IR (CsI): ν = 2921 (w), 1597 (s), 1539 (s), 1501 (vs), 1466 (s),
˜
1420 (s), 1399 (vs), 1315 (m), 1250 (s), 1231 (s), 1157 (vs), 1067 (w),
1020 (s), 897 (w), 840 (w), 810 (w), 752 (w), 687 (w), 623 (w), 549
(w) cm–1. UV/Vis (CH3CN, c = 1.1ϫ10–5 molL–1): λmax (ε,
Lmol–1 cm–1) = 215 (5.47ϫ104), 295 (8.17ϫ104), 369 (4.46ϫ104)
nm. MS (FAB): m/z (%) = 531 (8) [(ttmgb)(H)]+, 460 (12), 408 (30),
= 157.23, 138.09, 115.76 (CH), 39.70 (CH ) ppm. IR (CsI): ν =
˜
3
291 (49), 273 (9), 212 (25). Crystal data for 6(I3)2: C26H50N12I6, Mr
= 1292.18, 0.25ϫ0.25ϫ0.25 mm , triclinic, space group P1, a =
3001 (w), 2923 (w), 2871 (w), 2801 (w), 1597 (vs), 1498 (s), 1477
(s), 1459 (s), 1422 (s), 1372 (vs), 1235 (s), 1137 (vs), 1062 (w), 1020
(s), 878 (s), 803 (w), 787 (w), 754 (w), 727 (w), 683 (w), 664 (w),
556 (w) cm–1. UV/Vis (CH3CN, c = 3.0ϫ10–5 molL–1): λmax (ε,
Lmol–1 cm–1) = 218 (3.93ϫ104), 329 (1.36ϫ104) nm. MS (FAB):
m/z (%) = 532 (43) [(ttmgb)(H)2]+, 531 (100) [(ttmgb)(H)]+, 530 (64)
3
¯
8.1920(16) Å, b = 9.6060(19) Å, c = 13.928(3) Å, α = 108.13(3)°,
β = 91.51(3)°, γ = 96.60(3)°, V = 1032.5(4) Å3, Z = 1, dcalcd.
=
2.078 Mgm–3, Mo-Kα radiation (graphite monochromated, λ =
0.71073 Å), T = 200 K, θrange 1.54 to 30.00°. Reflections measured
24847, independent 5922, Rint = 0.0251. Final R indices [IϾ2σ(I)]:
R1 = 0.0332, wR2 = 0.0804.
[ttmgb], 486 (41) [ttmgb-N(CH3)2]. Crystal data for 6: C26H50N12,
3
¯
Mr = 530.78, 0.40ϫ0.30ϫ0.30 mm , triclinic, space group P1, a =
8.1570(16) Å, b = 8.8210(18) Å, c = 11.337(2) Å, α = 89.22(3)°, β
X-ray Crystallographic Study: Suitable crystals were taken directly
out of the mother liquor, immersed in perfluorinated polyether oil
and fixed on top of a glass capillary. Measurements were made
with a Nonius-Kappa CCD diffractometer with low-temperature
unit by using graphite-monochromated Mo-Kα radiation. The tem-
perature was set to 200 K. The data collected were processed by
using the standard Nonius software.[21] All calculations were per-
formed by using the SHELXT-PLUS software package. Structures
were solved by direct methods with the SHELXS-97 program and
refined with the SHELXL-97 program.[22,23] Graphical handling of
the structural data during solution and refinement was performed
with XPMA.[24] Atomic coordinates and anisotropic thermal pa-
rameters of non-hydrogen atoms were refined by full-matrix least-
squares calculations. CCDC-699399 (for 6), -699401 (for [6H4]
Cl4·9H2O), -699402 (for [6H2](PF6)2·1.5H2O) and -699400 [6(I3)2]
contain the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cam-
bridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
= 85.08(3)°, γ = 74.13(3)°, V = 781.7(3) Å3, Z = 1, dcalcd.
=
1.128 Mgm–3, Mo-Kα radiation (graphite monochromated, λ =
0.71073 Å), T = 200 K, θrange 2.40 to 30.0°. Reflections measured
38438, independent 4537, Rint = 0.0366. Final R indices [IϾ2σ(I)]:
R1 = 0.0504, wR2 = 0.1256.
[6H4]Cl4: To a solution of 6 (0.06 g, 1.1 mmol) dissolved in Et2O
(10 mL) was added Et2O·HCl (1 , 0.4 mL). After stirring for
30 min at room temperature the solvent was removed in vacuo. The
1
remaining white solid product was recrystallised from CH3CN. H
NMR (399.89 MHz, CD3CN): δ = 9.81 (s, 4 H), 6.66 (s, 2 H), 2.99
(s, 48 H, CH3) ppm. 13C NMR (100.56 MHz, CD3CN): δ = 159.64,
130.16, 118.67 (CH), 41.39 (CH3) ppm. MS (FAB): m/z (%) = 532
(32) [(ttmgb)(H)2]+, 531 (95) [(ttmgb)(H)]+, 530 (28) [ttmgb], 486
(50) [ttmgb-N(CH3)2], 408 (67), 379 (100), 260 (25), 202 (36). Crys-
tal data for [6H4]Cl4·9H2O: C26H54N12Cl4·9H2O, Mr = 1677.52,
0.40ϫ0.30ϫ0.30 mm3, monoclinic, space group C2/c,
a =
23.226(5) Å, b = 11.823(2) Å, c = 15.802(3) Å, β = 94.48(3)°, V
= 4326.0(15) Å3, Z = 4, dcalcd. = 1.288 Mgm–3, Mo-Kα radiation
(graphite monochromated, λ = 0.71073 Å), T = 200 K, θrange 1.76
Details of the Quantum Chemical Calculations: Calculations were
carried out with the aid of the TURBOMOLE program package[25]
Pure DFT calculations relied on the hybrid method B3LYP (DFT
by using Becke exchange functional and Lee–Yang–Parr corre-
to 35.00°. Reflections measured 106531, independent 9486, Rint
0.0555. Final R indices [IϾ2σ(I)]: R1 = 0.0415, wR2 = 0.0977.
=
[6H2](PF6)2: A mixture of 6 (0.030 g, 0.06 mmol) and [NH4]PF6
(0.016 g, 0.1 mmol) in CH3CN (20 mL) was stirred for 30 min at a lation functional, as well as Hartree–Fock exchange).[26] Calcula-
temperature of 50 °C. After evaporation of the solvent, the remain-
ing solid was redissolved in CH3CN. Then, a small amount of char-
tions on the solvent effect were carried out with the COSMO pro-
gram.[27]
Eur. J. Org. Chem. 2008, 5907–5914
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5913