3-(4-Cyanophenyl)pentane-2,4-dione and its copper(II) complex

Article abstract of DOI:10.1107/S0108270104002938

The structure of 3-(4-cyanophenyl)-pentane-2,4-dione (Hacac-C ₆H₄CN), (I) and its copper(II) complex, (II), was investigated. The β-diketone 3-(4-cyanophenyl)pentane-2,4-dione crystallize as the enol tautomer 4-(2-hydroxy-4-oxopent-2

Full text of DOI:10.1107/S0108270104002938

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
O1Á Á ÁO2 interaction are comparable to those reported for
other 3-phenylpentane-2,4-dione derivatives (Emsley et al.,
1989). The dihedral angle between the ꢀ-diketone plane and
the phenyl ring is 78.28 (4)ꢀ, and the H atoms on methyl group
C5 are disordered over two sets of sites.
ISSN 0108-2701
3-(4-Cyanophenyl)pentane-2,4-dione
and its copper(II) complex
Banglin Chen,³ Frank R. Fronczek and
Andrew W. Maverick*
Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803-1804,
USA
Correspondence e-mail: maverick@lsu.edu
Received 22 December 2003
Accepted 5 February 2004
Online 11 March 2004
In (II) (Fig. 2), although the two ꢀ-diketonate moieties are
almost coplanar with the Cu atom, they make an angle of
24.74 (6)ꢀ with each other. This conformation represents a
twisting distortion of the two ligands, away from square-planar
and towards tetrahedral geometry. Few four-coordinate
copper(II) ꢀ-diketonate complexes show this type of distor-
tion; of 59 such compounds for which coordinates are avail-
able in the Cambridge Structural Database (Allen et al., 1979),
eight showed a noticeable amount [refcodes BIBFIB10
(Wrobleski et al., 1984), CAXRUO (Prokop et al., 1999),
JOXGIM (Rees et al., 1992), NILMUQ (Schilde et al., 1997),
PENTUX (Baidini et al., 1992), SOJXIY01 (Polyanskaya et al.,
1993), TIRGIK (Schilde et al., 1996) and ZUVSOY (Hirsch et
al., 1996)]. The analogous dihedral angles for these structures
range from 4.33 to 24.5ꢀ, the largest value being for JOXGIM.
In the case of BIBFIB10 (20.2ꢀ), the distortion at the Cu atom
is probably attributable to ring strain, which results from the
Pt atom linking the two phosphino-ꢀ-diketone ligands. In the
other structures, there are no obvious intermolecular inter-
actions causing the distortions.
The ꢀ-diketone 3-(4-cyanophenyl)pentane-2,4-dione crystal-
lizes as the enol tautomer 4-(2-hydroxy-4-oxopent-2-en-3-
yl)benzonitrile, C12H11NO2, (I), with an intramolecular OÐ
Ê
HÁ Á ÁO hydrogen bond [OÁ Á ÁO = 2.456 (2) A]. Reaction of (I)
with copper acetate monohydrate in the presence of triethyl-
amine leads to the formation of the copper(II) complex
bis[3-(4-cyanophenyl)pentane-2,4-dionato-ꢁ2O,O]copper(II),
[Cu(C12H10NO2)2], (II). In the structure of (II), the Cu atom is
coordinated by four ꢀ-diketonate O atoms in a slightly
distorted square-planar geometry, with CuÐO distances in the
Ê
range 1.8946 (11)±1.9092 (11) A. The nitrile moieties in (II)
make it a candidate for reaction with other metal ions to
produce supramolecular structures.
Comment
Metal±ꢀ-diketonate complexes are of interest for their host±
guest chemistry (Soldatov & Ripmeester, 2001) and their
application in chemical vapor deposition (CVD) of metal ®lms
(Borgharkar et al., 1999; Maverick et al., 2002). Our previous
studies of metal±ꢀ-diketonate supramolecules (Maverick et
al., 1986, 2001) have shown that the metal centers in these
supramolecules can bind a variety of different guest molecules,
making these kinds of compounds potentially useful in
separation and sensors. The structures of 3-(4-cyanophenyl)-
pentane-2,4-dione (Hacac-C6H4CN), (I), and its copper(II)
complex, (II), are reported here. We are now attempting to
utilize coordination of the CN moieties in (II) to other metal
atoms in order to construct nanoporous materials.
The structure of (I) is shown in Fig. 1, and selected bond
distances and angles are listed in Table 1. The observation that
(I) exists as the enol tautomer is consistent with a solution
NMR study (Dell'Erba et al., 1991). The bond distances, angles
Ê
and hydrogen-bonding distance [2.456 (2) A; Table 2] for the
Figure 1
The structure of (I), showing the atom-numbering scheme and
displacement ellipsoids at the 50% probability level.
³ Current address: Department of Chemistry, The University of Texas±Pan
American, Edinburg, TX 78541-2999, USA.
Acta Cryst. (2004). C60, m147±m149
DOI: 10.1107/S0108270104002938
# 2004 International Union of Crystallography m147

metal-organic compounds
Figure 2
The structure of (II), showing the atom-numbering scheme and displacement ellipsoids at the 50% probability level.
Ê
The average CuÐO distance in (II) [1.900 (6) A; Table 3] is
0.25 mmol) in ethanol (5 ml) was mixed with [Cu(CH3COO)2(H2O)]
(0.05 g, 0.25 mmol) in H2O (5 ml), and several drops of triethylamine
were added. Compound (II) precipitated and was collected in 65%
yield. Recrystallization of the crude product from acetonitrile
produced crystals suitable for X-ray analysis.
slightly shorter than those found in two other copper(II)
Ê
cyano-ꢀ-diketone complexes, viz. Cu(acac-CN)2 [1.920 (2) A;
Hacac-CN is 3-cyanopentane-2,4-dione; Angelova et al., 1989]
Ê
and Cu(dpm-CN)2 [1.924 (3) A; Hdpm-CN is 4-cyano-2,2,6,6-
tetramethylheptane-3,5-dione; Silvernail et al., 2001]. The
dihedral angles between the ꢀ-diketone planes and the phenyl
rings are 71.07 (5) (O1/O2/C1±C5 and C6±C11) and 67.54 (5)ꢀ
(O3/O4/C13±C17 and C18±C23). The intramolecular N1Á Á ÁN2
Compound (I)
Crystal data
C12H11NO2
Mr = 201.22
Mo Kꢂ radiation
Cell parameters from 1990
re¯ections
Ê
distance is 20.286 (2) A, making (II) a very long building block
for construction of nanometer-sized porous materials.
Monoclinic, P21=c
a = 7.070 (5) A
ꢃ = 2.5±26.0ꢀ
Ê
It is of interest to compare the packing of (II), Cu(acac-
C6H4-CN)2, with that of other related metal-ꢀ-diketonate
building blocks. Unlike bis[3-(4-pyridyl)pentane-2,4-diona-
to]copper(II), which crystallizes in two- and three-dimensional
metal-organic frameworks because of intermolecular CuÁ Á ÁN
coordination (Turner et al., 1997; Chen et al., 2003), (II) is a
molecular solid without any intermolecular CuÁ Á ÁN(C) coor-
dination. Structures have been reported for three other bis-
(cyano-ꢀ-diketonato)metal(II) compounds. In the structure of
Cu(acac-CN)2 (Angelova et al., 1989), a ®fth coordination site
at the Cu atom is occupied by an N atom from an adjacent
Cu(acac-CN)2 group, leading to the formation of one-dimen-
sional Cu(acac-CN)2 chains. On the other hand, in the struc-
tures of Cu(dpm-CN)2 (Silvernail et al., 2001) and Co(acac-
CN)2 (Angelova et al., 1991), nitrile N atoms occupy both the
®fth and the sixth coordination sites, forming two-dimensional
Cu(dpm-CN)2 and three-dimensional Co(acac-CN)2 frame-
works. These structural variations occur mainly because
metal±nitrile coordination is weak. Thus, slight changes in the
ꢀ-diketone ligands and metal centers can cause substantial
changes in intermolecular interactions in the crystal. We are
now exploring the use of these metal-functionalized ꢀ-dike-
tonate `building blocks' in the construction of nanometer-sized
porous materials.
1
Ê
b = 11.644 (9) A
ꢄ = 0.09 mm
T = 100 K
Ê
c = 12.2430 (11) A
ꢀ = 94.035 (3)ꢀ
V = 1005.4 (11) A
Plate fragment, colorless
0.20 Â 0.10 Â 0.07 mm
3
Ê
Z = 4
Dx = 1.329 Mg m
3
Data collection
Nonius KappaCCD diffractometer
(with an Oxford Cryosystems
Cryostream cooler)
! scans with ꢁ offsets
8931 measured re¯ections
1969 independent re¯ections
1396 re¯ections with I > 2ꢅ(I)
Rint = 0.033
ꢃmax = 26.0ꢀ
h = 8 ! 8
k = 14 ! 14
l = 15 ! 15
Table 1
Selected geometric parameters (A, ) for (I).
ꢀ
Ê
O1ÐC2
O2ÐC4
N1ÐC12
1.276 (2)
1.314 (2)
1.150 (3)
C2ÐC3
C3ÐC4
1.427 (3)
1.389 (3)
O1ÐC2ÐC3
C4ÐC3ÐC2
120.99 (18)
119.00 (17)
O2ÐC4ÐC3
N1ÐC12ÐC9
121.28 (18)
178.9 (2)
C2ÐC3ÐC6ÐC7
79.7 (2)
Table 2
Hydrogen-bonding geometry (A, ) for (I).
ꢀ
Ê
Experimental
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
3-(4-Cyanophenyl)pentane-2,4-dione, (I), was synthesized according
to the procedure of Dell'Erba et al. (1991) and crystallized from
ether±dichloromethane (4:1 volume ratio). A solution of (I) (0.05 g,
O2ÐH2OÁ Á ÁO1
1.08 (3)
1.44 (3)
2.456 (2)
153 (2)
ꢁ
m148 Banglin Chen et al.
C12H11NO2 and [Cu(C12H10NO2)2]
Acta Cryst. (2004). C60, m147±m149

metal-organic compounds
Re®nement
positions in the expected torus. Uiso(H) values were taken to be
1.2Ueq of the attached atom (1.5Ueq for hydroxy and methyl atoms).
For both compounds, data collection: COLLECT (Nonius, 2000);
cell re®nement: HKL SCALEPACK (Otwinowski & Minor, 1997);
data reduction: HKL DENZO (Otwinowski & Minor, 1997) and
SCALEPACK; program(s) used to solve structure: SIR97 (Altomare
et al., 1999); program(s) used to re®ne structure: SHELXL97 (Shel-
drick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia,
1997); software used to prepare material for publication:
SHELXL97.
Re®nement on F2
R[F2 > 2ꢅ(F2)] = 0.051
wR(F2) = 0.138
S = 1.02
1969 re¯ections
140 parameters
H atoms treated by a mixture of
independent and constrained
re®nement
w = 1/[ꢅ2(F2o) + (0.0764P)2
+ 0.1248P]
where P = (F2o + 2Fc2)/3
(Á/ꢅ)max < 0.001
3
Ê
Áꢆmax = 0.22 e A
3
Ê
0.25 e A
Áꢆmin
=
Compound (II)
This research was supported by DOE (grant No. DE-FG02-
01ER15267) and the ACS Petroleum Research Fund (grant
No. 37234-AC3). A diffractometer upgrade was made possible
by grant No. LEQSF(1999±2000)-ENH-TR-13, administered
by the Louisiana Board of Regents.
Crystal data
[Cu(C12H10NO2)2]
Mr = 463.96
Triclinic, P1
Z = 2
Dx = 1.512 Mg m
Mo Kꢂ radiation
3
Ê
a = 7.6087 (10) A
Ê
b = 9.260 (2) A
Cell parameters from 6559
re¯ections
c = 15.198 (3) A
ꢃ = 2.5±32.0ꢀ
ꢄ = 1.11 mm
T = 100 K
Ê
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: HJ1000). Services for accessing these data are
described at the back of the journal.
1
ꢂ = 91.327 (8)ꢀ
ꢀ = 92.814 (8)ꢀ
ꢇ = 107.509 (12)ꢀ
Fragment, blue±green
0.22 Â 0.10 Â 0.07 mm
3
Ê
V = 1019.1 (3) A
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7082 re¯ections
285 parameters
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w = 1/[ꢅ2(F2o) + (0.0230P)2
+ 0.7093P]
where P = (F2o + 2Fc2)/3
(Á/ꢅ)max = 0.001
Áꢆmax = 0.44 e A
3
Ê
3
Ê
0.53 e A
Extinction correction: SHELXL97
Áꢆmin
=
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Table 3
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ꢀ
Ê
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Cu1ÐO2
Cu1ÐO4
O1ÐC2
1.8946 (11)
1.8954 (11)
1.9028 (11)
1.9092 (11)
1.2751 (18)
O2ÐC4
1.2823 (18)
1.2809 (18)
1.2757 (18)
1.147 (2)
O3ÐC14
O4ÐC16
N1ÐC12
N2ÐC24
1.148 (2)
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O1ÐCu1ÐO2
O3ÐCu1ÐO2
O1ÐCu1ÐO4
166.74 (5)
92.44 (5)
89.28 (5)
89.21 (5)
O3ÐCu1ÐO4
O2ÐCu1ÐO4
N1ÐC12ÐC9
N2ÐC24ÐC21
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166.07 (5)
177.52 (18)
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È
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The hydroxy H-atom positional parameters for (I) were re®ned.
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Ê
CÐH distances of 0.95±0.98 A, depending on atom type. A torsional
parameter was re®ned for each methyl group. Methyl group C5 in (I)
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ꢁ
Acta Cryst. (2004). C60, m147±m149
Banglin Chen et al.
C12H11NO2 and [Cu(C12H10NO2)2] m149