328
P. Xue et al. / Journal of Organometallic Chemistry 637–639 (2001) 327–334
of comparison, model compounds 5–8, which were not
reported before, were also synthesized (Scheme 1).
Phenyl was chosen in the model compounds as the
substitute for the reason that it exhibits the aromaticity
similar to pyridine, furan and ferrocene but without the
complexible atom or redox activity. In this paper, the
synthesis of compounds 5–8 and some coordination
compounds of 1 and 2 are presented, and FABMS,
UV–vis spectroscopy, and cyclic voltammetry (CV) are
employed to investigate the coordination chemistry and
the electrochemical behavior of compounds 1–8.
EtOH, to which a solution of benzyl chloride (0.60 g,
5.0 mmol) in EtOH (40 ml) was added in drops under
reflux. After the addition, 0.40 g (2.9 mmol) of K2CO3
was added and the mixture was heated under reflux for
an additional hour. After the solvent was evaporated
under reduced pressure, the residue was taken up in
CHCl3, and washed with water. The organic layer was
separated, dried over anhydrous Na2SO4, filtered and
concentrated under reduced pressure. The residue was
separated by column chromatography on silica. Com-
pound 6 was eluted by a mixture of CHCl3 and MeOH
(100:3, v/v), and purified by crystallization from
Me2CO. Yield: 0.30
g (15%), m.p. 150–152 °C.
2. Experimental
FABMS (exact mass, 394.24, m/z, %): 395 [M++1,
77]; 394 [M+, 9]; 303 [M+−91, 42]; 91 [C7H+7 , 100].
1H-NMR (CDCl3, 90 MHz, l ppm): 2.24–2.54 (m, 8H,
CH2NCH2CH2NCH2); 3.26 (s, 2H, COCH2CO); 3.28–
3.40 (m, 4H, CONCH2); 3.50 (s, 4H, PhCH2N); 6.64–
6.94 (s, br, 2H, CONH); 7.08–7.40 (m, 10H, C6H5). IR
(KBr pellet, cm−1): 3303 (s, of CONH); 3121 (m, of
aryl); 2928, 2833 (m, of alkyl); 1668, 1634 (s, of
CONH); 1535, 1550 (s, of CONH); 734 (m, mono-sub-
stituted phenyl); 698 (m, mono-substituted phenyl).
The mixture of CHCl3 and MeOH (100:5–8, v/v)
eluted compound 5, which was purified by crystalliza-
tion from Me2CO. Yield: 0.91 g (60%), m.p. 204–
206 °C. FABMS (exact mass, 304.19, m/z, %): 305
[M++1, 100]; 304 [M+, 8]; 213 [M+−91, 5]; 91
[C7H+7 , 80]. 1H-NMR (CDCl3, 90 MHz l ppm): 2.20 (s,
1H, CNHC); 2.40–2.76 (m, 8H, CH2NCH2CH2NCH2);
3.22 (s, 2H, COCH2CO); 3.24–3.50 (m, 4H, CONCH2);
3.60 (s, 4H, PhCH2N); 7.04–7.16 (m, 6H, CONH,
C6115); 8.00–8.24 (br, 1H, CONH). IR (KBr pellet,
cm−1): 3311, 3257 (m, of CONH); 3171 (m, of CNHC);
3125 (m, of aryl); 2940, 2831 (m, of alkyl); 1686, 1658
(s, of CONH); 1649, 1462 (m, of aryl); 1547 (s, of
CONH); 769 (m, mono-substituted phenyl); 694 (m,
mono-substituted phenyl).
2.1. General
4-Ferrocenylmethyl-1,4,7,10-tetraaza-cyclotridecane-
11,13-dione (1), 4,7-bis(ferrocenylmethyl)-1,4,7,10-tetra-
aza-cyclotridecane-11,13-dione (2), 4-ferrocenylmethyl-
7 - furfuryl - 1,4,7,10 - tetraaza - cyclotridecane - 11,13-
dione (3), 4-ferrocenylmethyl-7-picolyl-1,4,7,10-tetra-
aza-cyclotridecane-11,13-dione (4) were prepared ac-
cording to the method in our previous report [9]. Pi-
colyl chloride was prepared according to a procedure in
the literature [10]. The solvents used for the reaction
were thoroughly dried analytical reagents. All melting
points (m.p.) are uncorrected. IR spectra were obtained
on a Nicolet 170SX FT-IR or Shimadzu FT-IR 8000
spectrophotometer. Proton magnetic resonance spectra
(300 or 90 MHz) were recorded on a Varian Mercury-
VX 300 or a JEOL FX90Q spectrometer with Me4Si as
internal reference. Mass spectra (FAB) were recorded
on a ZAB 3F-HF spectrometer.
CV was performed in a conventional three-electrode
cell at 2091 °C, using a PAR Model 173 potentiostat/
galvanostat (EG&G), which was described in our previ-
ous report [8] except that the solvent was made of 2:1
(v/v) EtOH–H2O.
UV–vis spectra were recorded on a Shimadzu UV-
160A or UV-3100 spectrometer at 2091 °C in the
mixture of 2:1 (v/v) EtOH–H2O. The concentration of
the ligands was always 1.0 mM for both UV–vis and
electrochemical studies. The transition metal salts were
used as in electrochemical experiments (the details can
be found in the literature [7]). After the addition of
metal ions, the solutions of the ligands were adjusted to
pH 6–7 with NaOH (0.01 M).
2.2.2. 4-Benzyl-7-ferrocenylmethyl-1,4,7,10-tetraaza-
cyclotridecane-11,13-dione (7)
To a mixture of compound 1 (0.20 g, 0.48 mmol) and
K2CO3 (0.55 g, 4.0 mmol) in MeCN (10 ml), a solution
of benzyl chloride (0.070 g, 0.55 mmol) in MeCN (5 ml)
was added under reflux with stirring, the reaction was
monitored by TLC. After being heated under reflux for
18 h, the reactant mixture was worked-up as described
above, and separated by column chromatography on
alumina (100:2, CHCl3–MeOH, v/v), crystallization
from MeCN afforded an orange powder. Yield: 0.15 g
(62%), m.p. 152–154 °C. FABMS (exact mass, 502.20,
m/z, %): 503 [M++1, 27]; 502 [M+, 35]; 359 [M+−
199+56, 5]; 303 [M+−199, 28]; 212 [M+−199−91,
3]; 199 [C5H5FeC5H4CH+2 , 100]; 91 [C7H+7 , 60]. 1H-
NMR (CDCl3, 300 MHz, l ppm): 2.31–2.49 (m, 8H,
CH2NCH2CH2NCH2); 3.26 (s); 3.35–3.37 (m); 3.52 (s)
2.2. Synthesis of ligands 5–8
2.2.1. 4-Benzyl-1,4,7,10-tetraaza-cyclotridecane-
11,13-dione (5) and 4,7-bis(benzyl)-1,4,7,10-tetraaza-
cyclotridecane-11,13-dione (6)
1,4,7,10 - Tetraaza - cyclotridecane - 11,13 - dione (L0)
(1.50 g, 7.0 mmol) was dissolved in 40 ml of absolute