metal-organic compounds
mixture was stirred overnight at room temperature. The
precipitate which formed was filtered off, dried and dissolved
in pyridine. The vial was left overnight and brown plate-like
crystals of (I) was obtained by evaporation of the pyridine.
Spectroscopic analysis: 13C NMR (600 MHz, C5D5N): ꢂ 155.01,
152.25, 149.83, 142.76, 139.47, 138.32, 135.50, 132.11, 130.79,
130.33, 128.70, 126.45, 124.30, 123.48, 118.06, 116.54, 23.01,
21.30, 20.24; IR (ATR, ꢃ, cmꢁ1): 2018 (CO, vs), 1900 (CO, vs),
1507 (diazenyl, vs).
Complex (II) was synthesized by dissolving (NEt4)2[Re-
(CO)3Br3] (30 mg, 0.0389 mmol) in methanol (10 ml). 5,7-
Bis[2-(2-methylphenyl)diazen-1-yl]quinolin-8-ol
(14.4 mg,
Figure 1
The molecular structure of (I), showing the atom-numbering scheme and
displacement ellipsoids at the 50% probability level. H atoms have been
omitted for clarity.
0.0389 mmol) was added to the solution and the mixture was
stirred for 24 h. The red precipitate which formed was dried,
dissolved in pyridine and after evaporation of the solvent, red
cuboidal crystals of (II) were obtained. Spectroscopic analysis:
13C NMR (600 MHz, C5D5N): ꢂ 155.97, 151.50, 150.78, 140.42,
137.11, 136.45, 132.94, 129.65, 129.49, 129.33, 127.56, 127.43,
125.09, 124.43, 117.68, 117.14, 105.13, 98.60, 19.019; IR (ATR,
ꢃ, cmꢁ1): 2022 (CO, vs), 1894 (CO, vs), 1501 (diazenyl, vs),
1449 (diazenyl, vs).
workers (Basu Baul et al., 2006a,b, 2008a,b), which range
between 75.18 (4) and 73.53 (4)ꢃ.
In both (I) and (II), the pyridine ligands are slightly bent
towards the bidentate ligands, with N2—Re—O4 angles of
82.00 (13) and 81.1 (3)ꢃ, respectively. This same ‘bending’ is
observed in the structure of fac-[Re(2,4-Quin)(CO)3(Py)],
with an equivalent N—Re—O angle of 80.85ꢃ. Note, however,
that structure (II) exhibits disorder of the pyridine ligand, with
refined site-occupancy factors of 0.707 (12) and 0.293 (12).
The Re—CO distances of (I) vary between 1.909 (5) and
2.2. Refinement
Crystal data, data collection and structure refinement
details are summarized in Table 1. For (I) and (II), all H atoms
were positioned in geometrically idealized positions and
˚
1.924 (5) A, and those of (II) between 1.894 (3) and
˚
constrained to ride on their parent atoms, with C—H = 0.95 A
˚
1.922 (3) A. These are well within the range of distances seen
2
and Uiso(H) = 1.2Ueq(C) for sp CH, and with C—H = 0.98 A
˚
for other tricarbonylrhenium(I) structures (Schutte & Visser,
2008; Schutte et al., 2007, 2008, 2009, 2010, 2011, 2012a,b,c).
The Re—O bond lengths for the quinolin-8-ol ligands are
and Uiso(H) = 1.5Ueq(C) for methyl groups. For (I), a large
˚
residual electron-density peak is present less than 1 A from
the Re centre. This feature was not improved by the use of
alternative data processing or absorption correction methods.
For (II), the pyridine ligand was modelled as disordered over
two sites. Obtaining chemically reasonable geometries
required restraint of the geometry of the minor disorder
component to be similar to that of the major component [site-
occupation factor refined to 0.707 (12)] and imposition of
restraints upon the displacement parameters of the pyridine
ring. This gave a total of 60 restraints.
˚
almost equal at 2.121 (3) and 2.1256 (16) A for (I) and (II),
respectively, while the Re—N bond lengths are also similar at
˚
2.179 (4) and 2.163 (2) A, respectively. Interestingly, whilst the
Re—N and Re—O bond lengths are quite similar in both (I)
and (II), this was not found for related Sn complexes, where
the Sn—O and Sn—N bond lengths reported by Basu Baul
3. Results and discussion
In the crystal structures of both tricarbonyl(pyridine-ꢀN){5-[2-
(2,4,6-trimethylphenyl)diazen-1-yl]quinolin-8-olato-ꢀ2N1,O}-
rhenium(I), (I) (Fig. 1), and tricarbonyl(pyridine-ꢀN){5,7-
bis[2-(2-methylphenyl)diazen-1-yl]quinolin-8-olato-ꢀ2N1,O}-
rhenium(I), (II) (Fig. 2), the octahedral fac geometries are
slightly distorted, with chelate N1—Re—O4 bite angles of
76.85 (14) and 76.35 (7)ꢃ, and C3—Re—N2 angles of
176.50 (18) and 175.9 (3)ꢃ, respectively. This compares well
with the similar structure, fac-[Re(2,4-Quin)(CO)3(Py)] (2,4-
Quin is 2-carboxylatoquinoline-4-carboxylic acid and Py is
pyridine) reported by Schutte et al. (2011), with a chelate bite
angle of 75.66ꢃ and a carbonyl–Re–N(Py) angle of 178.01ꢃ.
The chelate bite angle also compares well with those of the
diazenylquinolin-8-ol ligands reported by Basu Baul and co-
Figure 2
The molecular structure of (II), showing the atom-numbering scheme and
displacement ellipsoids at the 50% probability level. H atoms have been
omitted for clarity. Both components of the disordered pyridine ligand
are shown.
ꢂ
Acta Cryst. (2013). C69, 1467–1471
Schutte-Smith et al.
[Re(C23H21N4O)(CO)3] and [Re(C28H23N6O)(CO)3] 1469