3600 Inorganic Chemistry, Vol. 36, No. 17, 1997
Dirghangi et al.
Table 6. Crystallographic Data for 5(Cl,Cl), 6(OMe,OMe), and
carboxaldimine chelated 4-6 by ∼0.7 V. The upshot of this
7(Me,Me)
is that the stable oxidation states of the imine and amide
complexes as isolated are +5 and +6, respectively. The amide
5(Cl,Cl)
6(OMe,OMe)
7(Me,Me)
1
complexes of type 7 display well-resolved EPR spectra (5dxy
)
empirical formula C19H15Cl5N3Re C26H23Cl3N3O2Re C20H18Cl3N3ORe
in solution even at room temperature, the six metal hyperfine
lines being unequally spaced due to second-order effects.
fw
648.8
P21/c
702.0
Pbca
12.079(5)
17.083(9)
26.049(9)
608.9
P21/c
space group
a, Å
b, Å
13.360(6)
12.110(3)
14.954(9)
111.41(4)
2252.4(1.7)
4
22
0.710 73
1.919
1.913
59.98
2.90
3.15
7.071(2)
17.541(6)
16.857(8)
100.59(3)
2055.3(1.3)
4
22
0.710 73
1.960
1.968
63.19
2.86
3.00
Experimental Section
c, Å
Materials. The complexes ReOCl3(PPh3)2,28 1(X),6a 2(X),6a and
pyridine-2-carboxaldimines29 were prepared by reported methods. The
purification and drying of dichloromethane and acetonitrile for synthesis
as well as electrochemical and spectral work were done as described
in an earlier work.30 Toluene was distilled over sodium before use.
All other chemicals and solvents were of reagent grade and were used
as received.
Physical Measurements. Spectra were recorded with the following
equipment: electronic spectra, Hitachi 330 spectrophotometer; infrared
spectra (KBr disk, 4000-300 cm-1), Perkin-Elmer 783 spectropho-
tometer; X-band EPR spectra, Varian E-109C spectrometer (calibrant
DPPH, g ) 2.0037). Electrochemical measurements were performed
by using a PAR model 370-4 electrochemistry system as described
elsewhere.31 All experiments were performed at a platinum working
electrodce under dinitrogen atmosphere, the supporting electrolyte being
tetraethylammonium perchlorate (TEAP). The potentials are referred
to the saturated calomel electrode (SCE) and are uncorrected for junction
contribution. Magnetic susceptibilities were measured on a PAR-155
vibrating-sample magnetometer. Microanalyses were performed using
a Perkin-Elmer 240C elemental analyzer. All compounds afforded
satisfactory elemental analyses, and only some representative instances
will be cited.
â, deg
V, Å3
Z
T, °C
λ, Å
5375.4(4.0)
8
22
0.710 73
1.730
1.735
48.47
3.63
F
F
obsd, g cm-3
calcd, g cm-3
µ, cm-1
R,a %
Rw,b %
3.81
a R ) ∑||Fo| - |Fc||/∑|Fo|. b Rw ) [∑w(|Fo| - |Fc|)2/∑w|Fo| ]1/2
;
2
w-1 ) σ2(|Fo|) + g|Fo| ; g ) 0.0002 for 5(Cl,Cl), 0.0001 for
2
6(OMe,OMe), and 0.0001 for 7(Me,Me).
toluene, along with an excess of p-chloroaniline (150 mg, 1.18 mmol),
and the solution was refluxed for 2 h. The resulting violet solution
was evaporated to dryness under reduced pressure, the solid mass
dissolved in 5 mL dichloromethane, and the solution subjected to
chromatography on a silica gel column (20 × 1 cm; 60-120 mesh,
BDH). A violet band eluted with a benzene-acetonitrile (10:1) mixture
was collected. Solvent evaporation afforded 56 mg (72%) of dark
crystalline 5(Cl,Cl) Anal. Calcd for 5(Cl,Cl), ReC19H15N3Cl5: C, 35.16;
H, 2.31; N, 6.48. Found: C, 35.60; H, 2.39; N, 6.40.
Synthesis of 4(X,Y). The complexes could be prepared from 1(X)
or 2(X) in 70-75% yields. The route from 2(X) is more convenient.
Details are given for one representative case.
Synthesis of 6(X,X). The complexes were prepared by the same
general procedure. Details are given for one representative case. Yields
were in the range 75-80%.
(Trichlorophenylimido)(N-phenylpyridine-2-carboxaldimine)rhe-
nium(V), 4(H,H). a. From 1(X). To a solution of 1(X)H) (50 mg,
0.10 mmol) suspended in 10 mL of toluene was added an excess of
aniline (150 mg, 1.61 mmol), and the mixture was refluxed for 1.5 h.
Evaporation of the solvent under reduced pressure gave a dark product,
and this was dissolved in a minimum volume of dichloromethane and
subjected to chromatographic workup. The violet band obtained by a
using benzene-acetonitrile (10:1) mixture as eluent was separated from
the mixture, and the required complex was obtained in ∼80% yield by
slow evaporation of the eluate.
b. From 2(X). A 100 mg (0.13 mmol) sample of 2(X)H) was
suspended in 10 mL of toluene, and the suspension was warmed to 60
°C. To it was added 160 mg (1.72 mmol) of aniline, and the mixture
was refluxed for 2 h. The resulting violet solution was evaporated to
dryness under reduced pressure. The solid mass thus obtained was
dissolved in 5 mL of dichloromethane and the solution subjected to
chromatography on a silica gel column (20 × 1 cm; 60-120 mesh,
BDH). Upon elution with benzene, a small yellow band separated out
which was rejected. The violet band that followed was eluted with a
benzene-acetonitrile (10:1) mixture. The required complex was
obtained from the eluate as dark shining microcrystals by slow
evaporation. Yield: 58 mg, 72%. Anal. Calcd for 4(H,H), ReC18-
H15N3Cl3: C, 38.19; H, 2.65; N, 7.43. Found: C, 37.90; H, 2.60; N,
7.51.
Trichloro-((p-methoxyphenyl)imido)(2-benzoylpyridine (p-meth-
oxyphenyl)imine)rhenium(V), 6(OMe,OMe). A mixture of 2-ben-
zoylpyridine (35 mg, 0.19 mmol) and p-anisidine (23 mg, 0.19 mmol)
was heated in the absence of any solvent for 10 min. The yellow oil
thus obtained was added to a suspension of ReOCl3(PPh3)2 (100 mg,
0.12 mmol) in 20 mL of toluene, along with an excess of p-anisidine
(150 mg, 1.22 mmol), and the solution was refluxed for 2 h.
Chromatographic workup of the resulting violet solution (as described
in the case of 5(X,X)) afforded dark crystalline 6(OMe,OMe) in 78%
(66 mg) yield. Anal. Calcd for 6(OMe,OMe), ReC26H23N3O2Cl3: C,
44.47; H, 3.28; N, 5.99. Found: C, 44.53; H, 3.35; N, 5.89.
Synthesis of 7(X,Y). The same general method was used to
synthesize the above complexes from 4(X,Y) as well as from 5(X,X).
Details are given for one representative case. Yields varied in the range
80-85%.
Trichloro-(p-tolylimido)(N-p-tolyl-2-picolinamido)rhenium-
(VI), 7(Me,Me). A 100 mg (0.16 mmol) sample of 5(Me,Me) was
dissolved in 20 mL of acetonitrile, and 0.2 mL of 0.5 N nitric acid
was added. The solution was stirred for 1 h, during which the color
turned brown. Solvent evaporation afforded a dark product, which was
repeatedly washed with water and dried in vacuo over P4O10. Yield:
85 mg (85%). Anal. Calcd for 7(Me,Me), ReC20H18N3OCl3: C, 39.44;
H, 2.96; N, 6.90. Found: C, 39.50; H, 2.88; N, 6.99.
Synthesis of 5(X,X). The complexes were prepared by the same
general method. Details are given for one representative case. Yields
were in the range 70-75%.
Trichloro((p-chlorophenyl)imido)(2-acetylpyridine (p-chlorophe-
nyl)imine)rhenium(V), 5(Cl,Cl). A mixture of 2-acetylpyridine (21
mg, 0.17 mmol) and p-chloroaniline (22 mg, 0.17 mmol) was heated
in the absence of any solvent for 10 min. This mixture was then added
to a suspension of ReOCl3(PPh3)2 (100 mg, 0.12 mmol) in 20 mL of
X-ray Structure Determination. Dimensions of the parallelepiped
crystals were 0.14 × 0.16 × 0.22 mm3 for 5(Cl,Cl), 0.54 × 0.46 ×
0.40 mm3 for 6(OMe,OMe), and 0.40 × 0.18 × 0.40 mm3 for 7(Me,-
Me). All three crystals were dark, and similar procedures were used
for all of them. Single crystals of complexes 5(Cl,Cl), 6(OMe,OMe),
and 7(Me,Me) were grown by slow diffusion of hexane into dichlo-
romethane solutions of the complexes.
Cell parameters were determined by a least-squares fit of 30 machine-
centered reflections (2θ ) 15-30°). Data were collected by the ω
scan technique in the range 3° e 2θ e 45° on a Siemens R3m/V four-
circle diffractometer with graphite-monochromated Mo KR radiation.
Two check reflections after each 198 reflections showed no intensity
reduction. All data were corrected for Lorentz-polarization effects
(28) Chatt, J.; Rowe, G. A. J. Chem. Soc. 1962, 4019.
(29) Bahr, G.; Thamlitz, H. Z. Anorg. Allg. Chem. 1955, 282, 3.
(30) Basu, P.; Bhanja Choudhury, S.; Chakravorty, A. Inorg. Chem. 1989,
28, 2680.
(31) Pramanik, A.; Bag, N.; Lahiri, G. K.; Chakravorty, A. Inorg. Chem.
1991, 30, 410.
Dirghangi, Bimal Kumar
