D. Sellmann, K. P. Peters, R. M. Molina, F. W. Heinemann
FULL PAPER
S2’-H2 (1) (2,3-dimercaptobenzoic acid methyl ester) was prepared
(150 mL) was added to the yellow residue to give a yellow emulsion
that was washed with Et2O (450 mL), and the yellow aqueous
phase was separated, filtered, and acidified slowly with concen-
trated hydrochloric acid (12 mL) at 0 °C. A white precipitate
formed which after stirring at room temperature for 15 min was
separated, washed with H2O (60 mL) and dried in vacuo. Yield:
as described in the literature.[4a]
‘CO2Me-S2’-iPr2 (1a): LiOMe (50 mmol, 50 mL of a 1 solution
in MeOH) and isopropyl bromide (5.87 mL, 62.5 mmol) were ad-
ded to
a light yellow solution of ‘CO2Me-S2’-H2 (5.01 g,
25.0 mmol) in MeOH (120 mL) and the resultant lemon yellow so-
lution heated under reflux for 20 h. After evaporation of the solv-
ent, CH2Cl2 (120 mL) was added to the residue and the resulting
suspension stirred for 2 h and then filtered. The filtrate was evapor-
ated to give a brown oil that was identified by NMR spectroscopy
as ‘CO2Me-S2’-iPr2 and was used for the synthesis of ‘CO2H-S2’-
iPr2 (2) without further purification. Yield: 7 g (1a) (100%). 1H
1
1.3 g (4) (81%). H NMR ([D8]THF, 269.72 MHz): δ ϭ 1.87 (m, 2
H, NCH2CH2), 3.47 (m, 4 H, NCH2CH2), 7.01 (vt, 2 H, C6H3),
7.33 (vd, 2 H, C6H3), 7.40 (vd, 2 H, C6H3), 7.94 (br, 2 H, NH)
ppm. 13C{1H} NMR ([D8]THF, 67.83 MHz):
δ
ϭ
29.5
(NHCH2CH2), 36.7 (NCH2CH2), 124.2, 125.1, 131.3, 132.7, 133.0,
134.6 (C6H3), 169.2 (CONH) ppm. IR (KBr): ν˜ ϭ 3280 (m, NϪH),
2526 (w, SϪH), 1628 (s, CϭO), 1534 cmϪ1 (s, NϪH). MS (FDϩ,
THF): m/z ϭ 411 [‘apS4’-H4]ϩ. C17H18N2O2S4 (410.61): calcd. C
49.73, H 4.42, N 6.82, S 31.24; found C 50.32, H 4.66, N 6.85,
S 30.79.
3
NMR (CDCl3, 269.72 MHz): δ ϭ 1.20 [d, JH,H ϭ 6.7 Hz, 6 H,
3
CH(CH3)2], 1.37 [d, JH,H ϭ 6.7 Hz, 6 H, CH(CH3)2], 3.50 [m, 2
H, CH(CH3)2], 3.89 (s, 6 H, CO2CH3), 7.26 (m, 3 H, C6H3) ppm.
MS (FDϩ, CH2Cl2): m/z ϭ 284 [‘CO2Me-S2’-iPr2]ϩ.
(AsPh4)2[{Fe(‘apS4’)}2] (5): A solution of FeCl3·6H2O (230 mg,
0.85 mmol) in MeOH (10 mL) was added to a solution of ‘apS4’-
H4 (4) (349 mg, 0.85 mmol) and LiOMe (3.40 mmol, 3.40 mL of a
1 solution in MeOH) in MeOH (25 mL). The resulting purple
solution was heated under reflux for 2 h. After removal of the solv-
ent, the resultant blackϪviolet residue was dissolved in MeOH
(30 mL) to give a black violet solution that was filtered and com-
bined with a solution of AsPh4Cl·H2O (1.23 g, 2.49 mmol) in
MeOH (25 mL). Violet microcrystals precipitated and were separ-
ated, washed with MeOH (20 mL) and dried in vacuo. Yield:
395 mg (5) (55%). 1H NMR ([D6]DMSO, 269.72 MHz): δ ϭ 7.8
[br, 40 H, As(C6H5)4ϩ] ppm. IR (KBr): ν˜ ϭ 3273 (m, NϪH), 1640
(s, CϭO), 1540 cmϪ1 (s, NϪH). MS (FDϩ, DMF): m/z ϭ 383
[AsPh4]ϩ; magnetic susceptibility: µeff ϭ 2.4 µB. UV/Vis (DMF,
10Ϫ4 ): λ ϭ 314 (22068), 364 (21139), and 512 (11464) nm
(cm2 molϪ1). C82H68As2Fe2N4O4S8 (1691.54): calcd. C 58.22, H
4.05, N 3.31, S 15.17; found C 58.27, H 4.22, N 3.36, S 15.05.
‘CO2H-S2’-iPr2 (2): NaOH (0.115 mmol, 115 mL of a 1 solution
in H2O) was added to a solution of ‘CO2Me-S2’-iPr2 (1a) (6.825 g,
0.024 mol) in THF (120 mL). The mixture was heated under reflux
for 29 h, then reduced in volume to about 120 mL and heated for
a further 15 h. The resulting pale pink solution was filtered. Con-
centrated hydrochloric acid (12 mL) was added to the filtrate and
the light yellow solid that precipitated was separated, washed with
water to pH ϭ 7 and dried in vacuo. Yield: 5.66 g (2) (87%). 1H
3
NMR (CDCl3, 269.72 MHz): δ ϭ 1.27 [d, JH,H ϭ 6.6 Hz, 6 H,
3
CH(CH3)2], 1.38 [d, JH,H ϭ 6.6 Hz, 6 H, CH(CH3)2], 3.52 [m, 2
H, CH(CH3)2], 7.41 (m, 2 H, C6H3), 7.87 (vdd, 1 H, C6H3), 11.75
(br, 1 H, COOH) ppm. 13C{1H} NMR (CDCl3, 67.83 MHz): δ ϭ
22.6, 22.8 [CH(CH3)2], 36.5, 41.2 [CH(CH3)2], 127.9, 129.3, 129.8,
130.3, 136.5, 146.4 (C6H3), 169.1 (CO2H) ppm. IR (KBr): ν˜ ϭ 2966
(br, OϪH), 1704 cmϪ1 (s, CϭO). MS (FDϩ, acetone): m/z ϭ 270
[‘CO2H-S2’-iPr2]ϩ. C13H18O2S2 (270.42): calcd. C 57.74, H 6.71, S
23.72; found C 57.49, H 6.99, S 23.90.
X-ray
Structure
Analyses
of
(AsPh4)2[{Fe(‘apS4’)}2]-
‘apS4’-iPr4 (3): SOCl2 (8.5 mL) was added to solid ‘CO2H-S2’-iPr2
(2) (4.815 g, 0.018 mol) and heated to 60 °C until no further gas
evolution was detected. Excess SOCl2 was removed in vacuo; the
brown oily residue obtained was dissolved in THF (30 mL) and a
solution of 1,3-diaminopropane (0.745 mL, 0.009 mol) and NEt3
(4.98 mL, 0.036 mol) in THF (20 mL) was added dropwise at 0 °C.
The resulting yellow suspension was stirred at room temperature
for 15 h, poured into ice water (600 mL) and stirred for a further
1 h. The mixture was extracted with Et2O (800 mL). The Et2O
phase was dried over Na2SO4, filtered and evaporated. The foam-
like solid thus obtained was washed with warm pentane which was
decanted. The residue was dried in vacuo yielding, again, a yellow
·2MeOH (5·2MeOH) and (AsPh4)2[{Fe(‘apS4’)}2] (5): Single
crystals were obtained by the following procedures.
(AsPh4)2[{Fe(‘apS4’)}2]·2MeOH (5·2MeOH): A solution of ‘apS4’-
H2 (44 mg, 0.11 mmol), LiOMe (0.43 mmol, 0.43 mL of a 1 solu-
tion in MeOH) and FeCl3·6H2O (29 mg, 0.11 mmol) in MeOH
(20 mL) was heated under reflux for 2 h. After cooling to room
temperature the resulting blackϪviolet solution was filtered and
layered with a solution of AsPh4Cl (115 mg, 0.28 mmol) in MeOH
(25 mL). Black blocks of (AsPh4)2[{Fe(‘apS4’)}2]·2MeOH
(5·2MeOH) formed that were separated after one week.
C84H76As2Fe2N4O6S8 (1755.63): calcd. C 57.47, H 4.36, N 3.19, S
14.61; found C 57.87, H 4.47, N 3.29, S 14.24.
1
foam-like solid material. Yield: 4.6 g (3) (88%). H NMR (CDCl3,
3
269.72 MHz): δ ϭ 1.19 (d, JH,H ϭ 6.7 Hz, 12 H, CHCH3), 1.36 (AsPh4)2[{Fe(‘apS4’)}2] (5): A concentrated and filtered solution of
3
[d, JH,H ϭ 6.7 Hz, 12 H, CH(CH3)2], 1.87 (m, 2 H, NCH2CH2),
3.46 (m, 4 H, NCH2CH2), 3.60 [m, 4 H, CH(CH3)2], 6.95 (br, 2 H, rhombs of (AsPh4)2[{Fe(‘apS4’)}2] (5) formed that were separated
NH), 7.26 (m,
H, C6H3) ppm. 13C{1H} NMR (CDCl3, after 2 months.
5 in DMF was layered with the same amount of THF. Black
6
67.83 MHz): δ ϭ 22.7, 23.2 [CH(CH3)2], 29.9 (NHCH2CH2), 36.0,
36.8 [CH(CH3)2], 40.5 (NCH2CH2), 124.6, 127.6, 128.8, 129.1,
143.8, 145.8 (C6H3), 169.5 (CONH) ppm. IR (KBr): ν˜ ϭ 3289 (s,
NϪH), 1636 (s, CϭO), 1522 cmϪ1 (s, NϪH). MS (FDϩ, Et2O):
m/z ϭ 578 [‘apS4’-iPr4]ϩ. C29H42N2O2S4 (578.93): calcd. C 60.17,
H 7.31, N 4.84, S 22.16; found C 60.27, H 7.70, N 4.58, S 21.92.
Suitable single crystals were embedded in protective perfluoro poly-
alkyl ether oil. Intensity data were collected at 100 K on a Nonius
KappaCCD diffractometer using Mo-Kα radiation (λ ϭ 71.073 pm,
graphite monochromator) (Table 2). Data were corrected for Lor-
entz and polarization effects and a numerical absorption correction
for 5·2MeOH and a semi-empirical absorption correction from
equivalent reflections for 5 were applied. The structures were solved
by direct methods, and full-matrix least-squares refinement was
carried out on F2 (SHELXTL NT 5.10).[11] All non-hydrogen
‘apS4’-H4 (4): Small pieces of sodium (0.9 g, 39 mmol) were added
to a solution of ‘apS4’-iPr4 (3) (2.25 g, 3.9 mmol) and naphthalene
(2.52 g, 19.5 mmol) in THF (200 mL). After stirring the resulting
green suspension for 16 h at room temperature, MeOH (15 mL) atoms were refined anisotropically. The positions of the hydrogen
was added cautiously. All solvents were evaporated and H2O
906
atoms were taken from the difference Fourier maps and refined
Eur. J. Inorg. Chem. 2003, 903Ϫ907