research communications
trans-bis(5-fluoroindoline-2,3-dione 3-oximato-κ2O2,N3)-trans-bis(pyridine-κN)copper(II)
and Hirshfeld analysis ofaEscola de Química e Alimentos, Universidade Federal do Rio Grande, Av. Itália km 08, Campus Carreiros, 96203-900 Rio Grande-RS, Brazil, and bDepartamento de Química, Universidade Federal de Sergipe, Av. Marechal Rondon s/n, 49100-000 São Cristóvão-SE, Brazil
*Correspondence e-mail: leandro_bresolin@yahoo.com.br
The reaction in methanol of CuII acetate monohydrate with 5-fluoroisatin 3-oxime deprotonated with KOH in a 1:2 molar ratio and recrystallization from pyridine yielded the title compound, [Cu(C8H4FN2O2)2(C5H5N)2]. In the centrosymmetric complex, the anionic form of the isatin oxime acts as a κ2N,O donor, building five-membered metallarings. The CuII cation is sixfold coordinated in a slightly distorted octahedral environment by two trans, equatorial, anionic isatin derivatives and two trans pyridine ligands in axial positions. The complexes are linked by hydrogen bonding into a three-dimensional network, which is also stabilized by π–π stacking interactions [centroid-to-centroid distance = 3.7352 (9) Å] and C—H⋯π contacts. The Hirshfeld surface analysis indicates that the major contributions for the crystal packing are H⋯H (31.80%), H⋯C (24.30%), H⋯O (15.20%) and H⋯F (10.80%). This work is the second report in the literature of a of a coordination compound with isatin 3-oxime ligands (coordination chemistry).
CCDC reference: 1826012
1. Chemical context
By the first half of the 19th century, the first reports on the chemistry of the isatin fragment were published independently in Germany and France (Erdmann, 1841a,b; Laurent, 1841). One very nice review concerning the organic synthesis of the isatin derivatives was published 74 years ago (Sumpter, 1944) and the topic remains up-to-date. From the early years, the chemistry of isatin-based molecules emerged from the synthetic approach to a large class of organic compounds with applications in biochemistry and pharmacology. For two recent examples, see: 1-[(2-methylbenzimidazol-1-yl) methyl]-2-oxo-indolin-3-ylidene]amino]thiourea, a derivative with in silico and in vitro inhibition of Chikungunya virus replication (Mishra et al., 2016) and 5-chloroisatin-4-methylthiosemicarbazone, another derivative which appears as an intermediate in the synthesis of an HIV-1 RT inhibitor (Meleddu et al., 2017). The abbreviation HIV-1 RT stands for human immunodeficiency virus type 1 reverse transcriptase. Along the same line of research of the present work, the the Hirshfeld surface analysis and the lock-and-key supramolecular analysis through in silico evaluation with the vascular endothelial growth factor receptor-2 (VEGFR-2) of the isatin derivative ligand of the title complex were recently carried out. The (3Z)-5-fluoro-3-(hydroxyimino)-indolin-2-one molecule showed a structure–activity relationship with the selected biological target through hydrogen bonding (Martins et al., 2017). Although the chemistry of isatins is already well reported in several scientific disciplines, crystal structures of complexes with isatin 3-oxime derivatives are surprisingly few in number. Thus, the determination of isatin-based molecules has become our major research interest and herein, the synthesis, and Hirshfeld surface analysis of a 5-fluoroisatin 3-oxime complex with copper(II) is reported.
2. Structural commentary
The II cation, which lies on an inversion center, and two ligands in general positions, the anionic form of 5-fluoroisatin 3-oxime and one pyridine molecule. The CuII atoms are sixfold coordinated in a slightly distorted octahedral environment by two five-membered chelate 5-fluoroisatin-3-oximate ligands, acting as κ2N,O-donors in equatorial positions, and by two pyridine ligands in axial positions (Fig. 1). The isatin 3-oxime derivative is nearly planar with an r.m.s. deviation from the mean plane of the non–H atoms of 0.0145 Å and a maximum deviation of 0.0344 (9) Å for the N2 atom. The dihedral angle between the pyridine ring and the mean plane through the indoline ring system is 73.82 (3)°. For the five-membered ring, the r.m.s. from the mean plane through the Cu1/C1/C2/N2/O1 fragment is 0.074 Å and the maximum deviation from that plane is 0.0945 (7) Å for the N2 atom. The N2—Cu1—N3 and O1—Cu1—N3 angles are 88.75 (4) and 89.01 (4)°, respectively. Four intramolecular C—H⋯O hydrogen bonds are observed for the title compound, forming rings with S(5) graph-set motif. As an interesting feature of the structure, a hydrogen-bonded macrocyclic coordination environment can be assumed based on the S(5) rings (Fig. 2, Table 1).
of the title coordination compound consists of one Cu3. Supramolecular features and Hirshfeld analysis
In the crystal, the molecules of the centrosymmetric title compound are connected into a three-dimensional hydrogen-bonded network (Table 1). The complexes are linked by centrosymmetric pairs of C—H⋯F interactions into dimers with graph-set motif R22(22). The dimers are the subunits of the periodic arrangement along the [110] direction (Fig. 3). The molecular units are also connected by C—H⋯O interactions into a one-dimensional hydrogen-bonded polymer along the [001] direction (Fig. 4) and finally, the complexes are linked by N—H⋯O interactions into centrosymmetric dimers with graph-set motif R22(14). Like the dimers of the first structural element, with C—H⋯F interactions connecting the molecules, the latter element is also based on dimers as subunits of the polymeric motif, connected through N—H⋯O interactions but in this case along the [010] direction (Fig. 5). In addition, π–π stacking interactions [centroid-to-centroid distance: 3.7352 (9) Å] and C—H⋯π contacts (Table 1) stabilize the crystal structure.
The Hirshfeld surface analysis (Hirshfeld, 1977) of the suggests that the contributions of the H⋯H, H⋯C and H⋯O intermolecular interactions to the crystal packing amount to 31.80, 24.30 and 15.20%, respectively. Other important intermolecular contacts for the cohesion of the structure are (values given in %): H⋯F = 10.80, C⋯C = 6.20, and H⋯N = 4.30. The contributions to the crystal cohesion are shown as two-dimensional Hirshfeld surface fingerprint plots with cyan dots (Wolff et al., 2012). The de (y axis) and di (x axis) values are the closest external and internal distances (values in Å) from given points on the Hirshfeld surface contacts (Fig. 6). The graphical representation of the Hirshfeld surface for the title compound with transparency and labelled atoms (Fig. 7) indicates, in magenta, the locations of the strongest intermolecular contacts, e.g. the H4, H7, H8, O2 and F1 atoms.
4. Database survey
A search of SciFinder (SciFinder, 2018) revealed a single report in the literature about the of coordination compounds with isatin 3-oxime derivatives, i.e. the one-dimensional coordination polymer, catena-poly[[[aquasodium]-di-μ-aqua-[aquasodium]-bis(μ-2-oxoindoline-2,3-dione 3-oximato)] tetrakis(oxoindoline-2,3-dione 3-oxime)] (Barreto Martins et al., 2011). For that complex, the Na cations shows an octahedral coordination environment builded by the anionic form of the isatin 3-oxime and water molecules (Fig. 8).
5. Synthesis and crystallization
All the starting materials were commercially available and were used without further purification. The synthesis of the ligand followed the procedure reported previously (Martins et al., 2017). 5-Fluoroisatin 3-oxime was dissolved in methanol (4 mmol, 50 mL) and deprotonated with one pellet of KOH with stirring maintained for 60 min. Simultaneously, a green solution of copper acetate monohydrate in methanol (2 mmol, 50 mL) was prepared under continuous stirring. A dark-coloured mixture of both solutions was maintained with stirring at room temperature for 8 h. A crude dark-red material was obtained by evaporation of the solvent. Purple crystals of the complex, suitable for X-ray analysis, were obtained by recrystallization of the solid from a pyridine/methanol (1:10 v/v) solution.
6. Refinement
Crystal data, data collection and structure . Hydrogen atoms were located in a difference-Fourier map, but were positioned with idealized geometry and refined isotropically using a riding model, with Uiso(H) = 1.2Ueq(C, N), and with C—H = 0.95 and N—H = 0.88 Å.
details are summarized in Table 2
|
Supporting information
CCDC reference: 1826012
https://doi.org/10.1107/S2056989018003365/rz5228sup1.cif
contains datablocks I, publication_text. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989018003365/rz5228Isup2.hkl
Data collection: APEX2 (Bruker, 2014); cell
SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2016 (Sheldrick, 2015b); molecular graphics: WinGX (Farrugia, 2012), DIAMOND (Brandenburg, 2006) and CrystalExplorer (Wolff et al., 2012); software used to prepare material for publication: publCIF (Westrip, 2010) and enCIFer (Allen et al., 2004).[Cu(C8H4FN2O2)2(C5H5N)2] | F(000) = 1180 |
Mr = 580.00 | Dx = 1.572 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 19.9709 (14) Å | Cell parameters from 9537 reflections |
b = 7.2155 (5) Å | θ = 2.4–32.7° |
c = 17.1989 (12) Å | µ = 0.95 mm−1 |
β = 98.579 (2)° | T = 200 K |
V = 2450.6 (3) Å3 | Prismatic, purple |
Z = 4 | 0.40 × 0.24 × 0.20 mm |
Bruker APEXII CCD diffractometer | 3966 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed X-ray tube, Bruker APEX2 CCD | Rint = 0.017 |
φ and ω scans | θmax = 32.7°, θmin = 2.1° |
Absorption correction: multi-scan (SADABS; Krause et al., 2015) | h = −30→30 |
Tmin = 0.674, Tmax = 0.746 | k = −10→7 |
18806 measured reflections | l = −26→26 |
4481 independent reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.033 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.086 | H-atom parameters constrained |
S = 1.12 | w = 1/[σ2(Fo2) + (0.035P)2 + 2.817P] where P = (Fo2 + 2Fc2)/3 |
4481 reflections | (Δ/σ)max < 0.001 |
178 parameters | Δρmax = 0.40 e Å−3 |
0 restraints | Δρmin = −0.34 e Å−3 |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.66193 (6) | 0.43044 (17) | 0.51144 (7) | 0.0202 (2) | |
C2 | 0.62981 (6) | 0.59529 (16) | 0.54136 (7) | 0.0179 (2) | |
C3 | 0.57200 (6) | 0.53285 (17) | 0.57616 (7) | 0.0190 (2) | |
C4 | 0.52421 (7) | 0.6220 (2) | 0.61397 (8) | 0.0252 (2) | |
H1 | 0.524139 | 0.752687 | 0.620565 | 0.030* | |
C5 | 0.47665 (7) | 0.5092 (2) | 0.64150 (10) | 0.0308 (3) | |
C6 | 0.47458 (7) | 0.3189 (2) | 0.63286 (10) | 0.0330 (3) | |
H2 | 0.440637 | 0.248844 | 0.652851 | 0.040* | |
C7 | 0.52236 (8) | 0.2300 (2) | 0.59479 (10) | 0.0292 (3) | |
H3 | 0.521610 | 0.099354 | 0.587721 | 0.035* | |
C8 | 0.57102 (6) | 0.33887 (17) | 0.56761 (8) | 0.0213 (2) | |
C9 | 0.79324 (7) | 0.8070 (2) | 0.66905 (8) | 0.0271 (3) | |
H5 | 0.778142 | 0.929489 | 0.656022 | 0.033* | |
C10 | 0.81834 (9) | 0.7655 (3) | 0.74669 (9) | 0.0361 (3) | |
H6 | 0.820299 | 0.858192 | 0.786181 | 0.043* | |
C11 | 0.84039 (8) | 0.5880 (3) | 0.76578 (9) | 0.0374 (4) | |
H7 | 0.857425 | 0.556392 | 0.818653 | 0.045* | |
C12 | 0.83737 (9) | 0.4571 (3) | 0.70703 (10) | 0.0359 (3) | |
H8 | 0.852688 | 0.334216 | 0.718775 | 0.043* | |
C13 | 0.81167 (8) | 0.5072 (2) | 0.63051 (9) | 0.0285 (3) | |
H9 | 0.809607 | 0.416673 | 0.590100 | 0.034* | |
Cu1 | 0.750000 | 0.750000 | 0.500000 | 0.01704 (6) | |
F1 | 0.42924 (6) | 0.59199 (17) | 0.67886 (8) | 0.0505 (3) | |
N1 | 0.62487 (6) | 0.28139 (15) | 0.52904 (8) | 0.0242 (2) | |
H4 | 0.633443 | 0.165583 | 0.517849 | 0.029* | |
N2 | 0.65751 (5) | 0.75711 (14) | 0.53373 (6) | 0.01704 (17) | |
N3 | 0.78961 (5) | 0.67952 (17) | 0.61181 (6) | 0.0208 (2) | |
O1 | 0.71204 (5) | 0.42959 (14) | 0.47722 (6) | 0.02501 (19) | |
O2 | 0.62959 (5) | 0.90531 (12) | 0.55624 (6) | 0.02333 (18) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0261 (5) | 0.0133 (5) | 0.0219 (5) | 0.0016 (4) | 0.0052 (4) | 0.0011 (4) |
C2 | 0.0209 (5) | 0.0130 (5) | 0.0204 (5) | 0.0011 (4) | 0.0051 (4) | 0.0007 (4) |
C3 | 0.0205 (5) | 0.0150 (5) | 0.0215 (5) | −0.0005 (4) | 0.0041 (4) | 0.0022 (4) |
C4 | 0.0254 (6) | 0.0219 (6) | 0.0299 (6) | 0.0018 (5) | 0.0092 (5) | 0.0011 (5) |
C5 | 0.0246 (6) | 0.0335 (8) | 0.0367 (7) | 0.0022 (5) | 0.0131 (5) | 0.0036 (6) |
C6 | 0.0254 (6) | 0.0329 (8) | 0.0420 (8) | −0.0059 (6) | 0.0098 (6) | 0.0092 (7) |
C7 | 0.0292 (6) | 0.0201 (6) | 0.0386 (7) | −0.0053 (5) | 0.0057 (5) | 0.0062 (5) |
C8 | 0.0237 (5) | 0.0145 (5) | 0.0255 (5) | −0.0007 (4) | 0.0036 (4) | 0.0033 (4) |
C9 | 0.0295 (6) | 0.0297 (7) | 0.0220 (6) | 0.0023 (5) | 0.0034 (5) | −0.0005 (5) |
C10 | 0.0398 (8) | 0.0476 (10) | 0.0199 (6) | −0.0019 (7) | 0.0009 (5) | −0.0030 (6) |
C11 | 0.0345 (7) | 0.0532 (11) | 0.0230 (6) | −0.0028 (7) | −0.0006 (5) | 0.0120 (6) |
C12 | 0.0375 (8) | 0.0367 (8) | 0.0327 (7) | 0.0066 (7) | 0.0026 (6) | 0.0141 (6) |
C13 | 0.0322 (6) | 0.0278 (7) | 0.0262 (6) | 0.0071 (5) | 0.0069 (5) | 0.0045 (5) |
Cu1 | 0.01925 (10) | 0.01681 (10) | 0.01575 (9) | 0.00118 (7) | 0.00488 (6) | 0.00176 (7) |
F1 | 0.0404 (5) | 0.0492 (7) | 0.0705 (8) | 0.0048 (5) | 0.0367 (5) | 0.0016 (6) |
N1 | 0.0325 (6) | 0.0093 (4) | 0.0326 (6) | 0.0007 (4) | 0.0108 (5) | 0.0011 (4) |
N2 | 0.0204 (4) | 0.0131 (4) | 0.0179 (4) | 0.0018 (3) | 0.0040 (3) | 0.0000 (3) |
N3 | 0.0203 (4) | 0.0249 (5) | 0.0182 (4) | 0.0027 (4) | 0.0064 (3) | 0.0029 (4) |
O1 | 0.0308 (5) | 0.0182 (4) | 0.0284 (5) | 0.0044 (4) | 0.0123 (4) | 0.0013 (4) |
O2 | 0.0297 (4) | 0.0122 (4) | 0.0301 (5) | 0.0025 (3) | 0.0113 (4) | −0.0021 (3) |
C1—O1 | 1.2342 (15) | C9—N3 | 1.3412 (19) |
C1—N1 | 1.3649 (16) | C9—C10 | 1.387 (2) |
C1—C2 | 1.4798 (17) | C9—H5 | 0.9500 |
C2—N2 | 1.3070 (15) | C10—C11 | 1.378 (3) |
C2—C3 | 1.4493 (16) | C10—H6 | 0.9500 |
C3—C4 | 1.3901 (18) | C11—C12 | 1.378 (3) |
C3—C8 | 1.4072 (17) | C11—H7 | 0.9500 |
C4—C5 | 1.386 (2) | C12—C13 | 1.387 (2) |
C4—H1 | 0.9500 | C12—H8 | 0.9500 |
C5—F1 | 1.3591 (17) | C13—N3 | 1.3423 (19) |
C5—C6 | 1.382 (2) | C13—H9 | 0.9500 |
C6—C7 | 1.392 (2) | Cu1—N2 | 2.0176 (10) |
C6—H2 | 0.9500 | Cu1—N3 | 2.0319 (11) |
C7—C8 | 1.3841 (18) | N1—H4 | 0.8800 |
C7—H3 | 0.9500 | N2—O2 | 1.2917 (13) |
C8—N1 | 1.4077 (17) | ||
O1—C1—N1 | 127.37 (12) | N3—C9—H5 | 119.0 |
O1—C1—C2 | 126.46 (12) | C10—C9—H5 | 119.0 |
N1—C1—C2 | 106.18 (11) | C11—C10—C9 | 119.13 (15) |
N2—C2—C3 | 133.98 (11) | C11—C10—H6 | 120.4 |
N2—C2—C1 | 118.12 (10) | C9—C10—H6 | 120.4 |
C3—C2—C1 | 107.89 (10) | C10—C11—C12 | 119.00 (14) |
C4—C3—C8 | 120.61 (12) | C10—C11—H7 | 120.5 |
C4—C3—C2 | 133.96 (12) | C12—C11—H7 | 120.5 |
C8—C3—C2 | 105.40 (11) | C11—C12—C13 | 119.13 (15) |
C5—C4—C3 | 116.20 (13) | C11—C12—H8 | 120.4 |
C5—C4—H1 | 121.9 | C13—C12—H8 | 120.4 |
C3—C4—H1 | 121.9 | N3—C13—C12 | 122.02 (15) |
F1—C5—C6 | 118.42 (13) | N3—C13—H9 | 119.0 |
F1—C5—C4 | 117.69 (14) | C12—C13—H9 | 119.0 |
C6—C5—C4 | 123.89 (14) | N2—Cu1—N3 | 88.75 (4) |
C5—C6—C7 | 119.82 (13) | O1—Cu1—N3 | 89.01 (4) |
C5—C6—H2 | 120.1 | C1—N1—C8 | 110.49 (10) |
C7—C6—H2 | 120.1 | C1—N1—H4 | 124.8 |
C8—C7—C6 | 117.53 (13) | C8—N1—H4 | 124.8 |
C8—C7—H3 | 121.2 | O2—N2—C2 | 120.09 (10) |
C6—C7—H3 | 121.2 | O2—N2—Cu1 | 124.18 (8) |
C7—C8—C3 | 121.93 (13) | C2—N2—Cu1 | 115.18 (8) |
C7—C8—N1 | 128.03 (12) | C9—N3—C13 | 118.66 (12) |
C3—C8—N1 | 110.04 (11) | C9—N3—Cu1 | 119.59 (10) |
N3—C9—C10 | 122.06 (15) | C13—N3—Cu1 | 121.74 (10) |
O1—C1—C2—N2 | −2.32 (19) | C4—C3—C8—N1 | −178.83 (12) |
N1—C1—C2—N2 | 177.94 (12) | C2—C3—C8—N1 | −0.40 (14) |
O1—C1—C2—C3 | 179.09 (13) | N3—C9—C10—C11 | 0.1 (2) |
N1—C1—C2—C3 | −0.65 (14) | C9—C10—C11—C12 | 0.5 (3) |
N2—C2—C3—C4 | 0.5 (3) | C10—C11—C12—C13 | −0.6 (3) |
C1—C2—C3—C4 | 178.76 (14) | C11—C12—C13—N3 | 0.0 (2) |
N2—C2—C3—C8 | −177.63 (14) | O1—C1—N1—C8 | −179.33 (13) |
C1—C2—C3—C8 | 0.63 (13) | C2—C1—N1—C8 | 0.41 (14) |
C8—C3—C4—C5 | −0.3 (2) | C7—C8—N1—C1 | 179.97 (14) |
C2—C3—C4—C5 | −178.20 (14) | C3—C8—N1—C1 | −0.01 (16) |
C3—C4—C5—F1 | 179.91 (13) | C3—C2—N2—O2 | −4.6 (2) |
C3—C4—C5—C6 | −0.4 (2) | C1—C2—N2—O2 | 177.27 (11) |
F1—C5—C6—C7 | 179.92 (15) | C3—C2—N2—Cu1 | 167.30 (11) |
C4—C5—C6—C7 | 0.2 (3) | C1—C2—N2—Cu1 | −10.83 (14) |
C5—C6—C7—C8 | 0.6 (2) | C10—C9—N3—C13 | −0.7 (2) |
C6—C7—C8—C3 | −1.3 (2) | C10—C9—N3—Cu1 | 178.48 (12) |
C6—C7—C8—N1 | 178.68 (14) | C12—C13—N3—C9 | 0.6 (2) |
C4—C3—C8—C7 | 1.2 (2) | C12—C13—N3—Cu1 | −178.54 (12) |
C2—C3—C8—C7 | 179.62 (13) |
Cg1 is the centroid of the N3/C9–C13 ring |
D—H···A | D—H | H···A | D···A | D—H···A |
C9—H5···O1i | 0.95 | 2.54 | 3.1424 (18) | 121 |
C12—H8···F1ii | 0.95 | 2.49 | 3.287 (2) | 142 |
C13—H9···O1 | 0.95 | 2.54 | 3.1077 (19) | 119 |
N1—H4···O2iii | 0.88 | 2.00 | 2.7529 (14) | 143 |
C6—H2···Cg1iv | 0.95 | 2.79 | 3.7076 (17) | 162 |
Symmetry codes: (i) −x+3/2, −y+3/2, −z+1; (ii) x+1/2, y−1/2, z; (iii) x, y−1, z; (iv) x−1/2, y−1/2, z. |
Acknowledgements
ABO is a former DAAD scholarship holder and alumnus of the University of Bonn, Germany, and thanks both of the institutions for long-term support, in particular Professor Johannes Beck and Dr Jörg Daniels.
Funding information
APLM thanks the CAPES foundation for a scholarship.
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