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Crystal structure of fac-aquatri­carbonyl[(S)-valin­ato-κ2N,O]­rhenium(I)

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aDepartment of Inorganic Chemistry, Ukrainian State University of Chemical Technology, Gagarin Ave. 8, Dnipropetrovsk 49005, Ukraine, and bInorganic Chemistry Department, National Taras Shevchenko University of Kyiv, Volodymyrska Street 64/13, Kyiv 01601, Ukraine
*Correspondence e-mail: ksenijapiletska@gmail.com

Edited by M. Weil, Vienna University of Technology, Austria (Received 19 March 2016; accepted 28 March 2016; online 31 March 2016)

In the mol­ecule of the title compound, [Re(C5H10NO2)(CO)3(H2O)], the ReI atom adopts a distorted octa­hedral coordination sphere defined by one aqua and three carbonyl ligands as well as one amino N and one carboxyl­ate O atom of the chelating valinate anion. The carbonyl ligands are arranged in a fac-configuration around the ReI ion. In the crystal, an intricate hydrogen-bonding system under participation of two O—H, two N—H and one C—H donor groups and the carboxyl­ate and carbonyl O atoms as acceptor groups contribute to the formation of a three-dimensional supra­molecular network.

1. Chemical context

The syntheses of metal–organic compounds, which are capable of visualization of biomolecules, is receiving growing inter­est in biocoordination chemistry (Coogan & Fernández-Moreira, 2014[Coogan, M. P. & Fernández-Moreira, V. (2014). Chem. Commun. 50, 384-399.]). For the labeling of biomolecules, octa­hedral fac-tricarbonyl complexes of Tc and Re are the most promising compounds (Alberto, 2007[Alberto, R. (2007). J. Organomet. Chem. 692, 1179-1186.]; Coogan et al., 2014[Coogan, M. P., Doyle, R. P., Valliant, J. F., Babich, J. W. & Zubieta, J. (2014). J. Label Compd. Radiopharm. 57, 255-261.]). The compact M(CO)3-core (M = Tc, Re) allows labeling of low mol­ecular weight substrates under retention of activity and specificity. In this context, Re(CO)3+ compounds are of inter­est as the closest non-radioactive analogs of 99mTc-based systems, which could be particularly important for visualization and immunotherapy. Studies of the cytotoxicity of rhenium carbonyl complexes also suggest their specific anti­cancer activity (Leonidova & Gasser, 2014[Leonidova, A. & Gasser, G. (2014). Chem. Biol. 9, 2180-2193.]).

[Scheme 1]

Most of the known Re(CO)3+ complexes with biologically essential substrates comprise tridentate co-ligands, e.g. histidinato-O,N,N′ (Alberto et al., 1999[Alberto, R., Schibli, R., Waibel, R., Abram, U. & Schubiger, A. P. (1999). Coord. Chem. Rev. 190-192, 901-919.]), me­thio­ninato-N,O,S (He et al., 2005[He, H., Lipowska, M., Xu, X., Taylor, A. T., Carlone, M. & Marzilli, L. G. (2005). Inorg. Chem. 44, 5437-5446.]), 2,3-di­amino­propionato-N,N′,O (Liu et al., 2006[Liu, Y., Pak, J. K., Schmutz, P., Bauwens, M., Mertens, J., Knight, H. & Alberto, R. (2006). J. Am. Chem. Soc. 128, 15996-15997.]), completing the coordination octa­hedra of the central ions. At the same time, coordinatively unsaturated complexes of bidentate amino­carboxyl­ates could be suited for inter­actions with additional ligands, such as guanine bases (Zobi et al. 2005a[Zobi, F., Spingler, B. & Alberto, R. (2005a). Dalton Trans. pp. 2859-2865.]), thus allowing an attractive scenario for the assembly of mixed-ligand systems.

In this communication, we report the synthesis and crystal structure of a novel Re(CO)3+ complex with valine and water as co-ligands. Following the findings of Zobi et al. (2005b[Zobi, F., Spingler, B. & Alberto, R. (2005b). ChemBioChem, 6, 1397-1405.]), sufficient reactivity of this compound towards DNA may be anti­cipated.

2. Structural commentary

In the mol­ecule of the title compound (Fig. 1[link]), the Re1 ion resides in a slightly distorted octa­hedral coordination environment, with a facial arrangement of three nearly equidistant carbonyl ligands [Re1—C bond lengths are in the range 1.881 (7)–1.909 (7) Å]. The compound crystallizes in the chiral space group P212121, with the S-enanti­omer of the valinate anion present in the selected crystal. The anion coordinates in a bidentate-chelating fashion through the amino N and one carboxyl­ate O atoms, with Re1—N1 and Re1—O4 bond lengths of 2.195 (5) and 2.122 (4) Å, respectively. The five-membered chelate ring [bite angle N1—Re1—O4 = 74.62 (18)°] has the expected envelope conformation, with the atoms of the Re1—O4—C4—C5 fragment being coplanar within 0.035 (3) Å and the N1 flap atom deviating from the given mean plane by 0.547 (6) Å. The Re1—O6 bond involving the aqua ligand [2.175 (5) Å] is slightly longer than the one with the carboxyl O atom. The CO ligands coordinate in an almost linear fashion, with O—C—Re bond angles spanning a range from 175.5 (7) to 179.9 (8)°, while the corresponding C—Re1—C angles are within 87.1 (3)–89.8 (2)°. All other bond length and angles are comparable to those found for related ReI complexes (Rajendran et al., 2000[Rajendran, T., Manimaran, B., Lee, F.-Y., Lee, G.-H., Peng, S.-M., Wang, C.-C. & Lu, K.-L. (2000). Inorg. Chem. 39, 2016-2017.]).

[Figure 1]
Figure 1
The mol­ecular structure of the title complex, with displacement ellipsoids drawn at the 40% probability level.

3. Supra­molecular features

In the crystal, the packing of the mol­ecules is governed by an intricate system of hydrogen bonds, including classical O—H⋯O and N—H⋯O bonds and weaker C—H⋯O inter­actions (Table 1[link]). Two rather strong and nearly linear O—H⋯O bonds are observed between the aqua ligand and the non-coordinating carboxyl­ate O atoms of two symmetry-related neighbouring mol­ecules. The amino group forms two weaker N—H⋯O bonds to carbonyl O atom acceptor groups of two neighbouring mol­ecules. Each non-coordinating carboxyl­ate O atom accepts two such bonds, yielding hydrogen-bonded chains parallel to the a-axis direction (Fig. 2[link]), whereas the N—H⋯O bonds expand the hydrogen-bonding system into a three-dimensional network. Additional C—H⋯O inter­actions consolidate this arrangement (Fig. 3[link]). The combination of O—H⋯O and C—H⋯O (involving the chiral C5 atom) bonds may be important for the observed enanti­oselective packing of the chiral moieties (Petkova et al., 2001[Petkova, E. G., Lampeka, R. D., Gorichko, M. V. & Domasevitch, K. V. (2001). Polyhedron, 20, 747-753.]).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O6—H1W⋯O5i 0.85 1.85 2.693 (5) 175
O6—H2W⋯O5ii 0.85 1.88 2.723 (5) 175
N1—H1N⋯O3iii 0.90 2.15 2.979 (7) 153
N1—H2N⋯O1iv 0.90 2.41 3.103 (6) 133
C5—H5⋯O2v 0.99 2.59 3.527 (7) 158
Symmetry codes: (i) x-1, y, z; (ii) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]; (iii) [-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (iv) x, y+1, z; (v) x+1, y, z.
[Figure 2]
Figure 2
Primary supra­molecular inter­actions involving rather strong O—H⋯O bonds that produce chains parallel to the a axis. [Symmetry codes: (i) x − 1, y, z; (ii) x − 0.5, −y + 0.5, −z + 1.]
[Figure 3]
Figure 3
The crystal structure of the title complex showing all hydrogen-bonding inter­actions (O—H⋯O, N—H⋯O and C—H⋯O) as dashed lines. The isopropyl CH-hydrogen atoms were omitted for clarity. [Symmetry codes: (i) x − 1, y, z; (iv) x, y + 1, z; (v) x + 1, y, z.]

4. Synthesis and crystallization

To a solution of DL-valine (0.116 g, 0.984 mmol) in 5 ml of water, a solution of tri­aqua­tri­carbonyl­rhenium(I) bromide (0.100 g, 0.246 mmol) in 10 ml of methanol was added. The reaction mixture was heated and stirred at 343 K under a steady stream of argon for 4 h. After cooling to room temperature, the solution was left to evaporate in air for a period of a few days. After removal of the methanol co-solvent, a colourless crystalline product formed. The precipitate was collected by suction filtration, washed with water and then with a 50 ml portion of petroleum ether and dried (yield: 0.068 g, 68%). Suitable single crystals were obtained by slow diffusion of hexane vapor into a methanol solution of the complex. IR (KBr, cm−1): νas(CO) 2028 (s), νs(CO) 1905 (s).

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. C-bound hydrogen atoms were placed geometrically and refined using a riding model, with C—H = 0.97 Å and Uiso(H) = 1.5Ueq(C) for methyl and with C—H = 0.99 Å and Uiso(H) = 1.2Ueq(C) for methine groups. N- and O-bound hydrogen atoms were found from difference maps and refined with N—H = 0.90 Å, O—H = 0.85 Å and Uiso(H) = 1.2Ueq(N,O).

Table 2
Experimental details

Crystal data
Chemical formula [Re(C5H10NO2)(CO)3(H2O)]
Mr 404.39
Crystal system, space group Orthorhombic, P212121
Temperature (K) 213
a, b, c (Å) 7.1229 (5), 7.2913 (7), 22.6098 (18)
V3) 1174.24 (17)
Z 4
Radiation type Mo Kα
μ (mm−1) 10.36
Crystal size (mm) 0.16 × 0.12 × 0.12
 
Data collection
Diffractometer Stoe Imaging plate diffraction system
Absorption correction Numerical (X-SHAPE and X-RED; Stoe, 2001[Stoe (2001). X-SHAPE and X-RED. Stoe & Cie GmbH, Darmstadt, Germany.])
Tmin, Tmax 0.288, 0.370
No. of measured, independent and observed [I > 2σ(I)] reflections 10442, 2809, 2546
Rint 0.040
(sin θ/λ)max−1) 0.660
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.022, 0.047, 0.99
No. of reflections 2809
No. of parameters 147
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 1.68, −0.91
Absolute structure Flack x determined using 990 quotients [(I+)−(I)]/[(I+)+(I)] (Parsons et al., 2013[Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249-259.]).
Absolute structure parameter −0.018 (10)
Computer programs: IPDS Software (Stoe, 2000[Stoe (2000). IPDS Software. Stoe & Cie GmbH, Darmstadt, Germany.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2014/7 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), DIAMOND (Brandenburg, 1999[Brandenburg, K. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.]) and WinGX (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]).

Supporting information


Computing details top

Data collection: IPDS Software (Stoe, 2000); cell refinement: IPDS Software (Stoe, 2000); data reduction: IPDS Software (Stoe, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 2012).

fac-Aquatricarbonyl[(S)-valinato-κ2N,O]rhenium(I) top
Crystal data top
[Re(C5H10NO2)(CO)3(H2O)]Dx = 2.287 Mg m3
Mr = 404.39Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P212121Cell parameters from 8000 reflections
a = 7.1229 (5) Åθ = 2.9–28.0°
b = 7.2913 (7) ŵ = 10.36 mm1
c = 22.6098 (18) ÅT = 213 K
V = 1174.24 (17) Å3Prism, colorless
Z = 40.16 × 0.12 × 0.12 mm
F(000) = 760
Data collection top
Stoe Imaging plate diffraction system
diffractometer
2546 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.040
φ oscillation scansθmax = 28.0°, θmin = 2.9°
Absorption correction: numerical
(X-SHAPE and X-RED; Stoe, 2001)
h = 99
Tmin = 0.288, Tmax = 0.370k = 99
10442 measured reflectionsl = 2929
2809 independent reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.022H-atom parameters constrained
wR(F2) = 0.047 w = 1/[σ2(Fo2) + (0.0254P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.99(Δ/σ)max = 0.002
2809 reflectionsΔρmax = 1.68 e Å3
147 parametersΔρmin = 0.91 e Å3
0 restraintsAbsolute structure: Flack x determined using 990 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013).
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.018 (10)
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Re10.27215 (3)0.24317 (4)0.36414 (2)0.01911 (8)
O10.1402 (9)0.1539 (7)0.3751 (3)0.0475 (16)
O20.0548 (9)0.3311 (10)0.2820 (3)0.059 (2)
O30.4865 (10)0.1103 (10)0.2566 (3)0.0510 (17)
O40.4953 (6)0.2146 (6)0.42564 (19)0.0201 (10)
O50.7729 (7)0.3107 (6)0.4559 (2)0.0296 (11)
O60.1463 (7)0.3556 (6)0.4439 (2)0.0216 (10)
H1W0.02760.34490.44550.032*
H2W0.19290.30460.47440.032*
N10.4095 (7)0.5125 (7)0.3670 (3)0.0202 (10)
H1N0.40120.55600.32980.030*
H2N0.35450.59440.39130.030*
C10.1826 (10)0.0024 (10)0.3716 (4)0.0300 (15)
C20.0674 (10)0.2983 (10)0.3127 (3)0.0309 (18)
C30.4063 (11)0.1628 (11)0.2973 (3)0.0283 (16)
C40.6284 (10)0.3294 (9)0.4248 (3)0.0215 (14)
C50.6095 (10)0.4941 (9)0.3839 (3)0.0216 (14)
H50.68140.46680.34750.026*
C60.6917 (11)0.6706 (9)0.4109 (4)0.0319 (16)
H60.82350.64460.42200.038*
C70.5880 (13)0.7280 (13)0.4668 (4)0.048 (2)
H7A0.46380.77210.45650.072*
H7B0.65740.82500.48640.072*
H7C0.57680.62360.49310.072*
C80.6942 (12)0.8254 (9)0.3654 (5)0.0424 (19)
H8A0.56640.86100.35610.064*
H8B0.75660.78370.32980.064*
H8C0.76130.92980.38160.064*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Re10.01711 (11)0.02296 (11)0.01726 (10)0.00198 (16)0.00083 (9)0.00125 (15)
O10.035 (3)0.027 (3)0.081 (5)0.005 (2)0.001 (3)0.002 (3)
O20.038 (4)0.091 (5)0.048 (4)0.017 (3)0.016 (3)0.006 (3)
O30.060 (5)0.061 (4)0.032 (3)0.016 (3)0.012 (3)0.006 (3)
O40.018 (2)0.020 (3)0.023 (2)0.0010 (17)0.0010 (17)0.0027 (17)
O50.015 (2)0.043 (2)0.030 (2)0.0011 (19)0.005 (2)0.0118 (19)
O60.019 (2)0.024 (2)0.022 (2)0.0027 (18)0.0015 (19)0.0026 (18)
N10.020 (3)0.020 (2)0.020 (3)0.0023 (19)0.002 (3)0.003 (2)
C10.020 (4)0.037 (4)0.032 (4)0.002 (3)0.004 (3)0.000 (3)
C20.023 (4)0.043 (5)0.026 (4)0.011 (3)0.010 (3)0.010 (3)
C30.027 (4)0.041 (4)0.016 (3)0.006 (3)0.005 (3)0.001 (3)
C40.017 (4)0.028 (3)0.019 (3)0.005 (3)0.003 (3)0.002 (2)
C50.017 (3)0.025 (3)0.023 (3)0.002 (2)0.000 (2)0.000 (2)
C60.024 (4)0.031 (3)0.041 (4)0.000 (3)0.005 (3)0.001 (3)
C70.055 (5)0.039 (5)0.050 (5)0.005 (5)0.006 (4)0.022 (4)
C80.033 (5)0.027 (3)0.066 (6)0.007 (3)0.002 (5)0.004 (4)
Geometric parameters (Å, º) top
Re1—C31.881 (7)N1—H1N0.9004
Re1—C21.908 (7)N1—H2N0.9004
Re1—C11.909 (7)C4—C51.520 (9)
Re1—O42.122 (4)C5—C61.539 (9)
Re1—O62.175 (5)C5—H50.9900
Re1—N12.195 (5)C6—C71.523 (11)
O1—C11.148 (9)C6—C81.526 (11)
O2—C21.139 (9)C6—H60.9900
O3—C31.148 (9)C7—H7A0.9700
O4—C41.265 (8)C7—H7B0.9700
O5—C41.255 (8)C7—H7C0.9700
O6—H1W0.8498C8—H8A0.9700
O6—H2W0.8503C8—H8B0.9700
N1—C51.482 (8)C8—H8C0.9700
C3—Re1—C288.0 (3)O5—C4—O4122.3 (6)
C3—Re1—C187.1 (3)O5—C4—C5119.9 (6)
C2—Re1—C189.8 (3)O4—C4—C5117.8 (6)
C3—Re1—O496.6 (3)N1—C5—C4108.3 (5)
C2—Re1—O4173.0 (2)N1—C5—C6113.1 (5)
C1—Re1—O495.8 (3)C4—C5—C6112.8 (6)
C3—Re1—O6173.2 (3)N1—C5—H5107.5
C2—Re1—O696.4 (3)C4—C5—H5107.5
C1—Re1—O698.2 (3)C6—C5—H5107.5
O4—Re1—O678.61 (18)C7—C6—C8111.2 (7)
C3—Re1—N194.4 (3)C7—C6—C5111.9 (6)
C2—Re1—N199.8 (3)C8—C6—C5110.9 (7)
C1—Re1—N1170.4 (3)C7—C6—H6107.5
O4—Re1—N174.62 (18)C8—C6—H6107.5
O6—Re1—N179.7 (2)C5—C6—H6107.5
C4—O4—Re1119.1 (4)C6—C7—H7A109.5
Re1—O6—H1W114.3C6—C7—H7B109.5
Re1—O6—H2W110.2H7A—C7—H7B109.5
H1W—O6—H2W108.2C6—C7—H7C109.5
C5—N1—Re1110.8 (4)H7A—C7—H7C109.5
C5—N1—H1N109.6H7B—C7—H7C109.5
Re1—N1—H1N105.0C6—C8—H8A109.5
C5—N1—H2N108.7C6—C8—H8B109.5
Re1—N1—H2N114.7H8A—C8—H8B109.5
H1N—N1—H2N107.9C6—C8—H8C109.5
O1—C1—Re1175.5 (7)H8A—C8—H8C109.5
O2—C2—Re1179.9 (8)H8B—C8—H8C109.5
O3—C3—Re1178.6 (7)
Re1—O4—C4—O5173.0 (5)O5—C4—C5—C637.3 (9)
Re1—O4—C4—C56.6 (7)O4—C4—C5—C6143.1 (6)
Re1—N1—C5—C431.1 (6)N1—C5—C6—C760.3 (8)
Re1—N1—C5—C6156.7 (5)C4—C5—C6—C763.0 (8)
O5—C4—C5—N1163.1 (6)N1—C5—C6—C864.5 (8)
O4—C4—C5—N117.2 (8)C4—C5—C6—C8172.2 (6)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O6—H1W···O5i0.851.852.693 (5)175
O6—H2W···O5ii0.851.882.723 (5)175
N1—H1N···O3iii0.902.152.979 (7)153
N1—H2N···O1iv0.902.413.103 (6)133
C5—H5···O2v0.992.593.527 (7)158
Symmetry codes: (i) x1, y, z; (ii) x1/2, y+1/2, z+1; (iii) x+1, y+1/2, z+1/2; (iv) x, y+1, z; (v) x+1, y, z.
 

Acknowledgements

This work was supported by the fund Grant for Science Research (No. 0111U000111) from the Ministry of Education and Science of Ukraine. We also thank EU COST Action CM 1105 for supporting this study.

References

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