J.L. Pratihar et al. / Inorganica Chimica Acta 367 (2011) 182–186
185
procedure [30]. IrCl3ꢁ3H2O was obtained from Arora-Mathey, India
and used as it was received. Silical gel G with binder was used for
thin layer chromatography. The ligands 2-(phenylazo)aniline
(HL1), 2-(p-tolylazo)aniline (HL2), and 2-(p-chlorophenylazo)ani-
line (HL3) were prepared following the reported procedures
[17–19].
(L2)(CH3OH)RhCl2 (3b): Yield: 60%. IrC14H16N3OCl2 (505): Anal.
Calc. C, 33.26; H, 3.16; N, 8.31. Found: C, 33.35; H, 3.19; N, 8.22.
UV–Vis spectrum (CH2Cl2) kmax
(1720), 365 (6770), 270 (4700), 230 (7660). IR (KBr pellets,
cmꢀ1): = 3191 (NH2), 1368(N@N). 1H NMR (CDCl3+ 1 drop
(e
, Mꢀ1 cmꢀ1) = 630 (520), 435
m
DMSO-d6, ppm): d 8.10–8.09 (m, 1H), 7.95–7.82 (m, 1H), 7.74 (s,
1H), 7.64–7.41 (m, 1H), 7.34–7.24 (m, 1H), 6.78 (d, 1H), 6.09 (s,
2H), 2.51 (s, 3H), 2.45 (s, 3H).
4.2. Physical measurements
4.3.4. (L3)(HL3)RhCl2 (2c) and (L3)(CH3OH)RhCl2 (3c)
Microanalysis (C, H, N) was performed using a Perkin–Elmer
2400 C, H, N, S/O series II elemental analyzer. Infrared spectra were
recorded on a Parkin-Elmer L120-00A FT-IR spectrometer with the
samples prepared as KBr pellets. Electronic spectra were recorded
on a Shimadzu UV-1800 PC spectrophotometer. 1H NMR spectra
were obtained on Brucker DPX 400 and Brucker 500 RPX NMR
spectrometers in CDCl3 or CDCl3-DMSO-d6 mixture using TMS as
the internal standard.
The complexes 2c and 3c were prepared following the same
procedure as in the cases of 2a and 3a using 2-(p-chloropheny-
lazo)aniline, 1c (160 mg, 0.76 mmol), in place of 1a. The solvent
used for thin layer chromatographic separation is toluene–metha-
nol (90:10 V/V) mixed solvent. Yield: 10% (for complex 2c) and 50%
(for complex 3c). IrC24H19N6Cl4 (725): Anal. Calc. C, 39.72; H, 2.61;
N, 11.57. Found: C, 39.83; H, 2.69; N, 11.67. UV–Vis spectrum
(CH2Cl2) kmax
(23,800), 275 (10,900), 235 (19,800). IR (KBr pellets, cmꢀ1):
= 3250, 3215, 3167 (NH2), 1373 (N@N). 1H NMR CDCl3: d 8.16–
(e,
Mꢀ1 cmꢀ1) = 620 (1100), 430 (3580), 350
4.3. Syntheses of complexes
m
4.3.1. (L)(HL)IrCl2 (2) and (L)(CH3OH)IrCl2 (3)
8.14 (m, 1H), 8.00 (d, 1H), 7.90–7.85 (m, 3H), 7.56–7.51 (m, 2H),
The (L)(HL)IrCl2 (2) and (L)(CH3OH)IrCl2 (3) complexes were ob-
tained by following a general procedure. Specific details are given
below for a particular complex.
7.47–7.24 (m, 7H), 7.01 (d, 1H), 4.78 (s, 2H), 3.56 (s, 2H).
(L3)(CH3OH)RhCl2 (3c): Yield: 60%. IrC13H13N3OCl3 (525.5):
Anal. Calc. C, 29.68; H, 2.47; N, 7.99. Found: C, 29.77; H, 2.53; N,
8.12. UV–Vis spectrum (CH2Cl2) kmax
435 (2480), 380 (8970), 360 (9960), 275 (7080), 230 (11,590). IR
(KBr pellets, cmꢀ1): = 3176 (NH2), 1373 (N@N). 1H NMR (CDCl3+
(e
, Mꢀ1 cmꢀ1) = 635 (770),
4.3.2. (L1)(HL1)IrCl2 (2a) and (L1)(CH3OH)IrCl2 (3a)
2-(Phenylazo)aniline, 1a, (60 mg, 0.30 mmol) was dissolved in
methanol (40 mL), and to it IrCl3 (100 mg, 0.15 mmol) was added.
The mixture was then heated to reflux for 4 h to afford green solu-
tion. Evaporation of the solvent gave a dark green residue, which
was introduced for purification by thin layer chromatography on
silica gel. Two green bands separated in toluene–methanol
(90:10, V/V) mixed solvent. From the first and second bands 2a
and 3a, respectively, were isolated in pure form upon extracting
with dichloromethane and methanol, respectively. Yield: 10% (for
complex 2a) and 60% (for complex 3a). IrC24H21N6Cl2 (656): Anal.
Calc. C, 43.90; H, 3.20; N, 12.80. Found: C, 43.45; H, 3.28; N,
m
1 drop DMSO-d6, ppm): d 8.14–8.09 (m, 1H), 7.90 (d, 1H), 7.83
(d, 1H), 7.67–7.59 (m, 1H), 7.36–7.25 (m, 2H), 6.95 (d, 1H), 6.22
(s, 2H), 2.52 (s, 3H).
4.3.5. Synthesis of (L1–3)(CH3OH)IrCl2 (4a–c)
(L)(CH3CN)IrCl2 (4) complexes were obtained from (L)(CH3O-
H)IrCl2 (3) upon refluxing in acetonitrile for 4 h to afford green
solution. Slow evaporation of the solvent gave crystals of
(L)(CH3CN)IrCl2 (4).
(L1)(CH3CN)IrCl2 (4a): Yield: 85%. IrC14H13N4Cl2 (500): Anal.
Calc. C, 33.60; H, 2.60; N, 11.20. Found: C, 33.74; H, 2.45; N,
12.65%. UV–Vis spectrum (CH2Cl2) kmax
(780), 430 (2730), 340 (19,660), 270 (9300), 235 (18,250). IR (KBr
pellets, cmꢀ1): = 3254, 3211, 3176 (NH2), 1372 (N@N). 1H NMR
(e,
Mꢀ1 cmꢀ1) = 620
11.02. UV–Vis spectrum (CH2Cl2) kmax
425 (3360), 360 (13,830), 265 (8550), 235 (11,250). IR (KBr pellets,
cmꢀ1): = 3254, 3209, 3191 (NH2), 1381 (N@N). 1H NMR (CDCl3+
(e
, Mꢀ1 cmꢀ1) = 620 (1240),
m
CDCl3: d 8.22–8.15 (m, 1H), 8.11 (d, 1H), 7.90–7.88 (m, 2H),
7.53–7.46 (m, 3H), 7.41–7.39 (m, 4H), 7.32–7.23 (m, 5H), 7.19 (t,
1H), 4.76 (s, 2H), 3.57 (s, 2H).
m
1
drop DMSO-d6, ppm): d 8.14 (d, 1H), 8.01 (d, 1H), 7.62–7.57 (m,
2H), 7.40 (t, 1H), 7.33 (t, 1H), 7.15 (t, 1H), 7.06 (t, 1H), 6.29 (s,
2H), 2.76 (s, 3H).
(L1)(CH3OH)IrCl2 (3a): Yield: 60 %. IrC13H14N3OCl2 (491): Anal.
Calc. C, 31.77; H, 2.85; N, 8.55. Found: C, 31.65; H, 2.73; N,
(L2)(CH3CN)IrCl2 (4b): Yield: 90%. IrC15H15N4Cl2 (514): Anal.
Calc. C, 35.01; H, 2.91; N, 10.89. Found: C, 35.22; H, 2.98; N,
8.74%. UV–Vis spectrum (CH2Cl2) kmax
440 (1790), 360 (7100), 230 (9580). IR (KBr pellets, cmꢀ1):
= 3216, 3185 (NH2), 1369 (N@N). 1H NMR (CDCl3+ 1 drop
(e
, Mꢀ1 cmꢀ1) = 640 (500),
10.75. UV–Vis spectrum (CH2Cl2) kmax
420 (3250), 380 (11,000), 270 (7100), 240 (10,500). IR (KBr pellets,
cmꢀ1): = 3252, 3203, 3099 (NH2), 1380 (N@N). 1H NMR (CDCl3+
(e
, Mꢀ1 cmꢀ1) = 615 (990),
m
DMSO-d6, ppm): d 8.15–8.13 (m, 1H), 8.01–7.91 (m, 2H), 7.59–
7.56 (m, 1H), 7.32–7.28 (m, 2H), 7.14–7.06 (m, 1H), 6.95 (t, 1H),
6.10 (s, 2H), 2.51 (s, 3H).
m
1
drop DMSO-d6, ppm): d 8.13 (d, 1H), 7.89 (d, 1H), 7.54 (d, 1H),
7.41–7.27 (m, 3H), 6.88 (d, 1H), 6.12 (s, 2H), 2.75 (s, 3H), 2.47 (s,
3H).
4.3.3. (L2)(HL2)RhCl2 (2b) and (L2)(CH3OH)RhCl2 (3b)
(L3)(CH3CN)RhCl2 (4c): Yield: 90%. IrC14H12N4Cl3 (534.5): Anal.
Calc. C, 31.43; H, 2.24; N, 10.47. Found: C, 31.56; H, 2.32; N,
The complexes 2b and 3b were prepared following the same
procedure as in the cases of 2a and 3a using 2-(p-tolylazo)aniline,
1b (160 mg, 0.76 mmol), in place of 1a. The solvent used for thin
layer chromatographic separation is toluene–methanol (90:10 V/
V) mixed solvent. Yield: 15% (for complex 2b) and 50% (for com-
plex 3b). IrC26H25N6Cl2 (684): Anal. Calc. C, 45.61; H, 3.65; N,
12.28. Found: C, 45.45; H, 3.60; N, 12.32. UV–Vis spectrum
10.50. UV–Vis spectrum (CH2Cl2) kmax
420 (3400), 380 (9900), 265 (7050), 235 (10,950). IR (KBr pellets,
cmꢀ1): = 3260, 3234 (NH2), 1404 (N@N). 1H NMR (CDCl3+ 1 drop
(e
, Mꢀ1 cmꢀ1) = 610 (1000),
m
DMSO-d6, ppm): d 8.21 (d, 1H), 8.02 (d, 1H); 7.63 (d, 1H), 7.58–7.54
(m, 1H), 7.51–7.48 (m, 1H), 7.40 (t, 1H), 7.14–7.12 (m, 1H), 6.27 (s,
2H), 2.84 (s, 3H).
(CH2Cl2) kmax
(37,000), 275 (16,000), 235 (29,400). IR (KBr pellets, cmꢀ1):
= 3250, 3215, 3167 (NH2), 1368 (N@N). 1H NMR CDCl3: d 8.16–
(e,
Mꢀ1 cmꢀ1) = 620 (1593), 430 (6080), 350
m
5. Crystallography
8.13 (m, 1H), 7.99 (d, 1H), 7.88–7.82 (m, 4H), 7.53–7.45 (m, 2H),
7.41–7.39 (m, 3H), 7.32–7. 20 (m, 6H), 6.94 (d, 1H), 4.75 (s, 2H),
3.56 (s, 2H), 2.53 (s, 3H), 2.40 (s, 3H).
Single crystals of (L)(HL)IrCl2 and (L)(MeCN)IrCl2 were grown by
slow diffusion of a dichloromethane solution into petroleum ether