A. Aballay et al. / Journal of Organometallic Chemistry 691 (2006) 2563–2566
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mining the type of the reaction observed when complexes
3.2. Thermal reactions of the complexes trans-(g5-
C5Me5)Re(CO)2 (chloroaryl)Cl (1) with acetonitrile
trans-Cp*Re(CO)2(ArCl)Cl, are dissolved in acetonitrile.
However, at this point we can not conclusively discard that
steric and/or electronic effects on the aryl ligand are influ-
encing factors affecting the preference of the starting com-
plexes to undergo the reductive coupling reactions instead
of isomerization. Studies on a more complete series of this
type of complexes possessing different aryl and halide
ligands are currently underway to further evaluate these
issues.
3.2.1. General procedure
Acetonitrile solutions containing the complexes
1
(100 mg) were heated under N2 at 40 ꢁC for 4 h. An IR
spectrum recorded after this time, showed the complete dis-
appearance of the two absorption bands of the starting rhe-
nium complexes and the appearance of two strong
absorptions at 1927 and 1840 cmꢀ1. The reaction mixture
was concentrated under vacuum to dryness. The residue
was washed with hexanes 3 · 10 mL and filtered through
a short column of Celite. The insoluble material was dis-
solved in CH3CN and filtered through Celite. Vacuum
evaporation of acetonitrile afforded a white solid of the
complex ReCl(CO)2(CH3CN)3 (3) (ꢁ70% yield).
3. Experimental
All reactions were carried out under nitrogen using
standard Schlenk techniques. Cp*Re(CO)3 was prepared
according to a procedure described in the literature
[14].
1,3-Dichlorobenzene
and
trimethylphosphite
IR (CH3CN, m(CO)/cmꢀ1): 1927 s and 1840 s; 1H NMR
(CD3CN) d: 1.95 (s, 3H, CH3CN), 2.46 (s, 6H, CH3CN).
13C{1H} NMR (CD3CN) d: 4.3 (s, CH3CN); 119.4 (s,
CH3CN); 123.4 (s, CH3CN); 194.7 (s, CO); 199.5 (s, CO).
M.p. 180 ꢁC with decomposition. Anal. Calc. for
C8H9O2ClRe: C, 26.74; H, 2.51. Found: C, 27.01; H,
2.40%.
(Aldrich) were used as received. Complexes trans-Cp*-
Re(CO)2(3-C6H3Cl-4-Me)Cl and trans-Cp*Re(CO)2(3,5-
C6H3Cl2)Cl were prepared as previously reported [7,9].
Photochemical reaction was carried out on a Rayonet
RPR 100 photoreactor. Infrared spectra were recorded
in solution (CaF2 cell) on a Perkin–Elmer FT-1605 spec-
trophotometer, 1H and 13C NMR spectra on a Bruker
The hexane solution was concentrated ca. 5 mL and
chromatographed on a neutral alumina column (10 cm).
Elutions with hexanes moved the corresponding complexes
2, which were obtained as a white solid after vacuum evap-
oration of the solvent. A mixture hexanes/CH2Cl2 (1:1)
moved small amount of the complex (3).
1
ADVANCE 400 spectrometer. H NMR chemical shifts
were referenced using the chemicals shifts of residual sol-
vent resonances, 13C chemical shifts to solvent peaks.
Mass spectra were obtained at the Laboratorio de Servi-
´
´
´
cios Analıticos, Universidad Catolica de Valparaıso.
Elemental analyses were obtained at the Centro de
´
´
Instrumentacion, P. Universidad Catolica de Chile, San-
tiago, Chile.
3.2.2. 5-(3-Chloro-4-methylphenyl)-1,2,3,4,5-
pentamethylcyclopentadiene (2a)
From 100 mg (0.186 mmol) of 1a, 39 mg (0.150 mmol)
of compound 2a was isolated as white microcrystals. Yield:
71%. 1H NMR (CD3CN) d: 1.27 (s, 3H); 1.55 (d,
J = 0.5 Hz, 6H); 1.83 (d, J = 0.5 Hz, 6H); 2.33 (s, (3-
C6H3Cl(4-CH3)), 3H); 6.84 (dd, J = 7.9, 1.8 Hz, 1H); 6.93
(d, J = 1.8 Hz, 1H); 7.18 (d, J = 7.9 Hz, 1H); 13C{1H}
NMR (CDCl3) d: 10.0 (s, C5Me5); 11.2 (s, C5Me5); 18.5
(s, C5Me5); 19.5 (s, 3-C6H3Cl(4-CH3)); 59.9 (s, C5Me5);
124.6; 126.8; 130.6; 133.0; 134.1; 134.2; 142.3; 143.6 (s, ole-
finic and aromatic carbons). Mass spectrum m/z: 260 [M+],
245 [M+ꢀMe], 230 [M+ꢀ2Me], 210 [M+ꢀClꢀMe]. M.p.
59 ꢁC. Anal. Calc. for C17H21Cl: C, 78.46; H, 8.08. Found:
C, 78.50; H, 8.10%.
3.1. trans-Cp*Re(CO)2(3-C6H4Cl)Cl (1c)
Five Pyrex tubes containing Cp*Re(CO)3 (100 mg;
0,247 mmol) dissolved in 15 mL of 1,3-dichlorobenzene,
were irradiated at 350 nm for 15 h. The resulting light yel-
low solutions were mixed and the solvent was removed
under vacuum. The residue was chromatographed on silica
gel column. Elution with hexanes moved the unreacted
Cp*Re(CO)3 (440 mg, 1.08 mmol). Hexanes/CH2Cl2 (5:1)
moved an orange band of trans-Cp*Re(CO)2 (3-C6H4Cl)Cl
containing traces of Cp*Re(CO)2Cl2. Recrystallization of
this mixture afforded pure orange crystals of trans-
Cp*Re(CO)2 (3-C6H4Cl)Cl (yield 25 mg, 0.048 mmol, 32%
conversion).
3.2.3. 5-(3,5-Dichlorophenyl)-1,2,3,4,5-
pentamethylcyclopentadiene (2b)
IR (CH2Cl2, m(CO)/cmꢀ1) : 2036s and 1957vs; 1H
NMR (CDCl3) d1.72 (s, 15H), 7.05 (m, 2H), 7.49 (td,
JH–H = 7.2, 1.6 Hz, 1H), 7.58 (t, JH–H = 1.6 Hz, 1H);
13C{1H} NMR (CDCl3) d: 9.3 (C5Me5), 103.5 (C5Me5);
125.3; 128.8; 129.9; 134.4; 143.4; 144.6 (C6H4Cl)
(C6H4Cl), 196.9 (CO); mass spectrum (based on
187Re/35Cl) m/z 524 [M]+, 496 [MꢀCO]+, 468
[Mꢀ2CO]+, 356 [Mꢀ2COꢀC6H4Cl]+. Anal. Calc. for
C18H19O2Cl2Re: C, 41.22; H, 3.65. Found: C, 40.09; H,
3.82%.
From 100 mg (0.179 mmol) of 1b 36 mg (0.129 mmol),
1
compound 2b was isolated as white solid. Yield: 72%. H
NMR (CD3CN) d: 1.29 (s, 3H), 1.56 (d, J = 0.4 Hz, 6H),
1.84 (d, J = 0.4 Hz, 6H), 6.92 (d, J = 1.9 Hz, 2H), 7.27 (t,
J = 1.9 Hz, 1H). 13C{1H} NMR (CDCl3) d: 9.9 (s,
C5Me5); 11.2 (s, C5Me5); 18.2 (s, C5Me5), 60.1 (s,
C5Me5), 124.9, 125.9, 134.6, 135.0, 143.2, 146.9 (s, olefinic
and aromatic carbons). Mass spectrum m/z: 280 [M+], 265
[M+ꢀMe], 250 [M+ꢀ2Me], 230 [M+ꢀClꢀMe]. M.p. 69 ꢁC.