M. Amirnasr et al. / Inorganica Chimica Acta 371 (2011) 6–12
7
Infrared spectra (KBr pellets) were obtained on a FT-IR JASCO 680
plus spectrophotometer. 1H NMR spectra were measured with a
Bruker AVANCE DR X500 spectrometer (500 MHz). Proton chemi-
cal shifts are reported in ppm relative to Me4Si as internal stan-
dard. The redox properties of the complexes were studied by
cyclic voltammetry. Cyclic voltammograms were recorded by
using a SAMA 500 Research Analyzer. Three electrodes were uti-
lized in this system, a glassy carbon working electrode, a platinum
disk auxiliary electrode and a silver wire as reference electrode.
The glassy carbon working electrode (Metrohm 6.1204.110) with
Complexes of the type [CoIII{(naph)2dpt}(amine)]BPh4 were
prepared by a procedure similar to that for [CoIII{(naph)2dien}(ami-
ne)]BPh4 except that H2(naph)2dpt ligand (439 mg, 1 mmol) was
used instead of H2(naph)2dien.
2.2.3.1. [Co{(naph)2dien}(pprdn)]BPh4 (1). Dark brown crystals of
(1) were obtained after 72 h in methanol. The crystals were filtered
off, washed with cold methanol and dried under vacuum. Yield
65%. Anal. Calc. for C55H54BCoN4O2: C, 75.69; H, 6.24; N, 6.42.
Found: C, 75.29; H, 6.31; N, 6.45%. FT-IR (KBr, cmꢀ1
)
m
max: 3254
2.0 0.1 mm diameter was manually cleaned with 1
lm alumina
(m, N–H), 1618 (s, C@N). UV–Vis: kmax (nm) (
e
, L molꢀ1 cmꢀ1
)
polish prior to each scan. Tetrabutylammonium hexafluorophos-
phate (TBAH) was used as supporting electrolyte. Cyclic voltam-
metric measurements were performed in dichloromethane. The
solutions were deoxygenated by purging with Ar for 5 min. All
electrochemical potentials were calibrated versus internal Fc+/0
(E0 = 0.46 V versus SCE) couple under the same conditions [41].
(CH2Cl2): 589 (350), 445 (4700), 423 (5060), 322 (sh, 19 000),
220 (190 000). 1H NMR (CDCl3, 500 MHz): d = 1.1–3.8 (m, 20H,
ꢀ
0
0
0
Ha,a ,b,b ,NH,pprdn), 6.93–7.78 (m, 32H, Hnaphthyl;BPh ), 8.21 (s, 2H, Hc,c ).
4
2.2.3.2. [Co{(naph)2dien}(prldn)]BPh4 (2). Dark brown crystals of (2)
suitable for X-ray analysis were obtained after 72 h in methanol.
The crystals were filtered off, washed with cold methanol and
dried under vacuum. Yield 66%. Anal. Calc. for C54H52BCoN4O2: C,
75.52; H, 6.10; N, 6.52. Found: C, 75.57; H, 6.01; N, 6.59%. FT-IR
2.2. Synthesis
2.2.1. Synthesis of H2(naph)2dien ligand
(KBr, cmꢀ1
kmax (nm) (
(6600), 322 (21 000), 221 (170 000). 1H NMR (CDCl3, 500 MHz):
)
e
m
max: 3254, 3223 (m, N–H), 1617 (s, C@N). UV–Vis:
Bis-(2-hydroxy-1-naphthaldimine)-N-diethylenetriamine,
H2(naph)2dien, was synthesized by the literature method [40] with
some modification leading to a higher yield. A solution of diethyl-
enetriamine (dien) (103 mg, 1 mmol) in methanol (25 mL) was
added to a solution of 2-hydroxy-1-naphthaldehyde (344 mg,
2 mmol) in methanol (25 mL) at room temperature and the reac-
tion mixture was stirred for 1 h. The product was precipitated as
a yellow powder by adding water. The precipitate was then filtered
off, washed with diethyl ether and dried under vacuum. Yield 95%.
Anal. Calc. for C26H25N3O2: C, 75.89; H, 6.12; N, 10.21. Found: C,
, L molꢀ1 cmꢀ1) (CH2Cl2): 582 (330), 445 (5500), 423
0
0
d = 1.26–3.47 (m, 18H,
H
a,a ,b,b ,NH,prldn), 6.93–7.78 (m, 32H,
0
ꢀ
Hnaphthyl;BPh ), 8.26 (s, 2H, H c,c ).
4
2.2.3.3. [Co{(naph)2dien}(py)]BPh4 (3). Dark brown crystals of (3)
were obtained after 48 h in methanol. The crystals were filtered
off, washed with cold methanol and dried under vacuum. Yield
75%. Anal. Calc. for C55H48BCoN4O2: C, 76.22; H, 5.58; N, 6.46.
Found: C, 75.06; H, 5.52; N, 6.37%. FT-IR (KBr, cmꢀ1
)
m
max: 3234
75.55; H, 6.04; N, 10.25%. FT-IR (KBr, cmꢀ1
1633 (s, C@N). UV–Vis: kmax (nm) (
)
m
max: 3282 (m, N–H),
(m, N–H), 1616 (s, C@N). UV–Vis: kmax (nm) (
e
, L molꢀ1 cmꢀ1
)
e
, L molꢀ1 cmꢀ1) (CH2Cl2): 419
(CH2Cl2): 582 (514), 445 (sh, 5700), 423 (6200), 316 (18 500),
(22 000), 403 (24 000), 308 (52 000), 233 (160 000). 1H NMR
(CDCl3, 500 MHz): d = 1.81 (br, 1H, NH), 3.03 (t, 4H, Ha), 3.71 (t,
4H, Hb), 6.90 (d, 2H, Hi), 7.21 (dd, 2H, Hf), 7.38 (dd, 2H, He), 7.58
(d, 2H, Hg), 7.65 (d, 2H, Hh), 7.84 (d, 2H, Hd), 8.79 (s, 2H, Hc),
14.44 (s, 2H, OH).
229 (71 900). 1H NMR (CDCl3, 500 MHz): d = 2.00 (br, 1H, NH),
0
0
3.17–3.33 (m, 4H, Ha,a ), 3.43–3.58 (m, 4H, Hb,b ), 6.92–8.01 (m,
ꢀ
0
37H, Hnaphthyl;py;BPh ), 8.36, 8.37 (s, 2H, Hc,c ).
4
2.2.3.4. [Co{(naph)2dien}(N-MeIm)]BPh4 (4). Dark brown crystals
were obtained after 48 h in methanol. The crystals were filtered
off, washed with cold methanol and dried under vacuum. Yield
70%. Anal. Calc. for C54H49BCoN5O2: C, 74.57; H, 5.68; N, 8.05.
2.2.2. Synthesis of H2(naph)2dpt ligand
Bis-(2-hydroxy-1-naphthaldimine)-N-dipropylenetriamine
(H2(naph)2dpt) was prepared by a procedure similar to that of
H2(naph)2dien except that dipropylenetriamine (dpt) (131 mg,
1 mmol) was used instead of diethylenetriamine (dien). Yield
90%. Anal. Calc. for C28H29N3O2ꢁH2O: C, 73.50; H, 6.83; N, 9.18.
Found: C, 74.54; H, 5.61; N, 8.13%. FT-IR (KBr, cmꢀ1
)
m
max: 3261
(m, N–H), 1617 (s, C@N). UV–Vis: kmax (nm) (
e
, L molꢀ1 cmꢀ1
)
(CH2Cl2): 558 (402), 447 (5400), 424 (5200), 321 (18 000), 221
(120 000). 1H NMR (CDCl3, 500 MHz): d = 1.74–3.62 (m, 9H,
Found: C, 73.81; H, 6.80; N, 9.23%. FT-IR (KBr, cmꢀ1
)
m
max: 3274
H
a,a ,b,b ,NH), 3.68 (s, 3H, Hmethyl), 6.92–7.83 (m, 35H,
0
0
, L molꢀ1 cmꢀ1
)
Hnaphthyl;NꢀMeIm;BPh ).
ꢀ
(m, N–H), 1631 (s, C@N). UV–Vis: kmax (nm) (
e
4
(CH2Cl2): 421 (17 000), 403 (16 000), 306 (24 000), 232 (93 000).
1H NMR (CDCl3, 500 MHz): d = 1.91 (m, 4H, Hb), 2.77 (t, 4H, Ha),
3.71 (t, 4H, Hc), 6.90 (d, 2H, Hj), 7.20 (dd, 2H, Hg), 7.38 (dd, 2H,
Hf), 7.58 (d, 2H, Hh), 7.66 (d, 2H, Hi), 7.82 (d, 2H, He), 8.71 (s, 2H,
Hd).
2.2.3.5. [Co{(naph)2dpt}(pprdn)]BPh4 (5). Dark brown crystals of (5)
were obtained after 72 h in methanol. The crystals were filtered off,
washed with cold methanol and dried under vacuum. Yield 60%.
Anal. Calc. for C57H58BCoN4O2: C, 76.00; H, 6.49; N, 6.22. Found:
C, 74.02; H, 6.48; N, 6.29%. FT-IR (KBr, cmꢀ1
H), 1617 (s, C@N). UV–Vis: kmax (nm) (
626.5 (237), 419 (6700), 403 (7500), 326 (17 800), 266 (65 000).
)
m
max: 3205 (m, N–
2.2.3. Synthesis of the cobalt complexes
e
, L molꢀ1 cmꢀ1) (CH2Cl2):
Complexes of the type [CoIII{(naph)2dien}(amine)]BPh4 were
prepared by the following general method. To a stirring solution
of Co(CH3COO)2ꢁ4H2O (249 mg, 1 mmol) in methanol (25 mL)
was added an equimolar amount of the H2(naph)2dien ligand
(411 mg, 1 mmol) in methanol (25 mL). The pink solution turned
brown immediately due to the formation of the [CoII{(naph)2dien}]
complex. To this solution was then added the appropriate amine
(4 mmol) and air was bubbled through the reaction mixture for
about 3 h. To the final green-brown solution was added NaBPh4
(342 mg, 1 mmol). Dark green crystals were obtained from the fil-
trate by the slow evaporation of the solvent. The crystals were fil-
tered off, washed with cold methanol and dried under vacuum.
1H
NMR
(CDCl3,
500 MHz):
d = 0.84–5.06
(m,
24H,
ꢀ
0
0
0
Ha,a ,b,b ,c,c ,NH,pprdn), 6.79–7.76 (m, 32H, Hnaphthyl;BPh ), 8.24, 8.30 (s,
4
0
2H, Hd,d ).
2.2.3.6. [Co{(naph)2dpt}(3-Mepy)]BPh4 (6). Dark brown crystals of
(6) were obtained after 72 h in methanol. Recrystallization from
dichloromethane:ethanol:1-propanol (2:1:1 v/v) gave dark brown
crystals suitable for X-ray analysis that were filtered off, washed
with cold methanol and dried under vacuum. Yield 76%. Anal. Calc.
for C58H54BCoN4O2: C, 76.65; H, 5.99; N, 6.16. Found: C, 76.59; H,
6.90; N, 6.22%. FT-IR (KBr, cmꢀ1
) mmax: 3220 (m, N–H), 1618 (s,