Abstract
C18H16O3N4Re, monoclinic, P21/c (no. 14), a = 9.8409(6) Å, b = 14.0933(9) Å, c = 13.9153(9) Å, β = 90.558(2)°, V = 1929.8(2) Å3, Z = 4, Rgt(F) = 0.0266, wRref(F2) = 0.0584, T = 100(2) K.
The molecular structure is shown in the Figure. Table 1 contains crystallographic data, and Table 2 contains the list of the atoms including atomic coordinates and displacement parameters.
Data collection and handling.
| Crystal: | Yellow block |
| Size: | 0.20 × 0.17 × 0.10 mm |
| Wavelength: | Mo Kα radiation (0.71073 Å) |
| μ: | 6.35 mm−1 |
| Diffractometer, scan mode: | Bruker APEX-II, φ and ω |
| θmax, completeness: | 26.1°, >99% |
| N(hkl)measured, N(hkl)unique, Rint: | 25,596, 3854, 0.064 |
| Criterion for Iobs, N(hkl)gt: | Iobs > 2 σ(Iobs), 3315 |
| N(param)refined: | 273 |
| Programs: | Bruker [1], SIR97 [2], Olex2 [3], SHELX [4], Diamond [5] |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2).
| Atom | x | y | z | Uiso*/Ueq |
|---|---|---|---|---|
| Re1 | 0.36523 (2) | 0.36667 (2) | 0.15167 (2) | 0.01396 (7) |
| O1 | 0.4160 (3) | 0.3151 (2) | −0.0595 (2) | 0.0264 (7) |
| O2 | 0.5057 (3) | 0.1840 (2) | 0.2198 (2) | 0.0262 (7) |
| O3 | 0.6380 (3) | 0.4703 (2) | 0.1279 (2) | 0.0243 (7) |
| O4 | 0.6958 (3) | 0.3629 (2) | 0.3347 (2) | 0.0241 (7) |
| O5 | 0.6997 (3) | 0.5165 (2) | 0.3356 (2) | 0.0257 (7) |
| O6 | 0.8885 (3) | 0.4380 (2) | 0.3395 (3) | 0.0359 (9) |
| N1 | 0.1627 (3) | 0.3057 (2) | 0.1449 (2) | 0.0137 (7) |
| N2 | 0.2300 (3) | 0.4857 (2) | 0.1288 (2) | 0.0145 (7) |
| N3 | 0.3273 (3) | 0.4026 (3) | 0.3010 (2) | 0.0160 (7) |
| N4 | 0.4256 (3) | 0.4002 (3) | 0.3699 (2) | 0.0177 (8) |
| H4 | 0.511688 | 0.387514 | 0.359227 | 0.021* |
| N5 | 0.7630 (3) | 0.4398 (3) | 0.3361 (2) | 0.0200 (8) |
| C1 | 0.3933 (4) | 0.3347 (3) | 0.0188 (3) | 0.0193 (10) |
| C2 | 0.4571 (4) | 0.2529 (3) | 0.1925 (3) | 0.0189 (9) |
| C3 | 0.5366 (4) | 0.4316 (3) | 0.1429 (3) | 0.0186 (10) |
| C4 | 0.1367 (4) | 0.2118 (3) | 0.1458 (3) | 0.0160 (9) |
| H4A | 0.209268 | 0.169252 | 0.159136 | 0.019* |
| C5 | 0.0098 (4) | 0.1753 (3) | 0.1285 (3) | 0.0179 (9) |
| H5 | −0.003982 | 0.108613 | 0.129190 | 0.021* |
| C6 | −0.0989 (4) | 0.2360 (3) | 0.1097 (3) | 0.0163 (9) |
| C7 | −0.2374 (4) | 0.1983 (3) | 0.0841 (3) | 0.0257 (11) |
| H7A | −0.303757 | 0.250042 | 0.086171 | 0.039* |
| H7B | −0.262891 | 0.148950 | 0.130138 | 0.039* |
| H7C | −0.235731 | 0.171266 | 0.019210 | 0.039* |
| C8 | −0.0722 (4) | 0.3320 (3) | 0.1119 (3) | 0.0152 (9) |
| H8 | −0.144425 | 0.375800 | 0.101995 | 0.018* |
| C9 | 0.0581 (4) | 0.3657 (3) | 0.1285 (3) | 0.0148 (9) |
| C10 | 0.0936 (4) | 0.4671 (3) | 0.1268 (3) | 0.0118 (8) |
| C11 | −0.0010 (4) | 0.5396 (3) | 0.1253 (3) | 0.0152 (9) |
| H11 | −0.095228 | 0.525011 | 0.123859 | 0.018* |
| C12 | 0.0410 (4) | 0.6336 (3) | 0.1258 (3) | 0.0164 (9) |
| C13 | −0.0610 (4) | 0.7129 (3) | 0.1215 (3) | 0.0208 (10) |
| H13A | −0.073396 | 0.733384 | 0.054624 | 0.031* |
| H13B | −0.028121 | 0.766444 | 0.160198 | 0.031* |
| H13C | −0.148006 | 0.690739 | 0.146723 | 0.031* |
| C14 | 0.1789 (5) | 0.6515 (3) | 0.1301 (3) | 0.0197 (10) |
| H14 | 0.210879 | 0.715056 | 0.132844 | 0.024* |
| C15 | 0.2698 (4) | 0.5775 (3) | 0.1306 (3) | 0.0169 (9) |
| H15 | 0.364265 | 0.591403 | 0.132226 | 0.020* |
| C16 | 0.2138 (4) | 0.4253 (3) | 0.3478 (3) | 0.0165 (9) |
| H16 | 0.127329 | 0.432742 | 0.317796 | 0.020* |
| C17 | 0.2380 (4) | 0.4367 (3) | 0.4455 (3) | 0.0178 (9) |
| H17 | 0.174469 | 0.452672 | 0.493854 | 0.021* |
| C18 | 0.3742 (4) | 0.4196 (3) | 0.4565 (3) | 0.0191 (10) |
| H18 | 0.423711 | 0.421314 | 0.515383 | 0.023* |
Source of material
The starting complex was synthesized according to a published procedure [14]: fac-[Re(Ddpy)(CO)3(H2O)]+ (30.00 mg; 0.063 mmol) was dissolved in methanol (5 ml) and pyrazole (4.316 mg, 0.063 mmol) was added; followed by refluxing for 24 h. The bright yellow solid was obtained by evaporation of the solvent, and the product was recrystallized using cold methanol.
IR (FTIR cm−1): vco = 2021.6, 1888.1, 1618.
Experimental details
All the hydrogen atoms were positioned geometrically and refined discernibly using a riding model, with fixed C-Hmethyl = 0.96 Å; C-HAromatic = 0.97 Å. The H atoms isotropic displacement parameters were fixed; Uiso(H) = 1.2Ueq(C) for aromatic and Uiso(H) = 1.5Ueq(C) for methyl, allowing them to ride on the parent atom. The graphics were obtained using the DIAMOND program with 50% probability ellipsoids. All the H-atoms on the title structure were omitted for clarity.
Comment
The applications of the fac-[M(H2O)3(CO)3]+ synthon, (M = Tc-99m, Re) and the introduction of nanotechnology merged with coordination chemistry, generally referred to as nano-medicine is a highly investigated field due to their prospective and existing applications in radiochemistry [6], [7], [8], [9]. Nanoparticles are the major system used in nano-medicine as theranostic agents because of their high molecular specificity which permit them to absorb high quantities of drugs [10], [11], [12].
The molecular structure of the title complex comprises three facial tricarbonyl ligands, a 4,4-dimethyl-2,2-dipyridyl bidentate ligand in the equatorial plane which is trans to two of the carbonyl ligands and a N-coordinated pyrazole monodentate ligand in the axial position. The complex was obtained from the [2 + 1] mixed ligand system on the fac-[M(H2O)3(CO)3]+ moiety.
The model involves the substitution of the two labile water molecules in the equatorial plane, followed by the coordination of the mono-dentate aqua ligand in the axial position; and the complex is neutralized by a nitrate counter-ion. The polyhedron geometry of the title complex reveals an octahedral distortion around rhenium(I). The distortion is evident in the angles of 167.56(14)° and 171.99(14)° for C2–Re1–N2 and C3–Re1–N1 respectively. The bite angle of the chelate ligand of 74.76(12)° from the title structure correlates well with those observed in literature reported similar structures [13], [14]. The bond distances between rhenium and the coordinated N atoms in the first coordination sphere ranges between 2.162(3) Å and 2.174(3) Å whereas the bond distances between the rhenium and the carbonyl carbon atoms ranges between 1.923(5) Å and 1.926(5) Å.
Funding source: National Research Foundation
Award Identifier / Grant number: 113629
Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: The authors would like to express the gratitude towards NRF (Thuthuka grant specific number 113629) for financial assistance. We would also like to acknowledge Tshwane University of Technology for Institutional support.
Conflict of interest: The authors declare no conflicts of interest regarding this article.
References
1. Bruker. SAINT–Plus (Version7. 12) and SADABS (Version 2004/1); Bruker AxS Inc.: Madison, Wisconsin, USA, 2004.Search in Google Scholar
2. Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G., Spagna, R. A new tool for crystal structure determination and refinement. J. Appl. Cryst. 1999, 32, 115–119; https://doi.org/10.1107/s0021889898007717.Search in Google Scholar
3. Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K., Puschmann, H. OLEX2: a complete structure solution, refinement and analysis program. J. Appl. Cryst. 2009, 42, 339–341; https://doi.org/10.1107/s0021889808042726.Search in Google Scholar
4. Sheldrick, G. M. A short history of SHELX. Acta Crystallogr. 2008, A64, 112–122; https://doi.org/10.1107/s0108767307043930.Search in Google Scholar PubMed
5. Brandenbug, K., Putz, H. DIAMOND. Visual Crystal Structure Information System. Ver. 3; 0c Crystal Impact GbR: Bonn, Germany, 2005.Search in Google Scholar
6. Alberto, R., Schibli, R., Egi, A., Schubiger, A. P., Abram, U., Kaden, T. A. A novel organometallic aqua complex of technetium for the labelling of biomolecules: synthesis of [99Tc (OH2)(CO)3]+ from [99mTc (OH)4]− in aqueous solution and its reaction with a bifunctional ligand. J. Am. Chem. Soc. 1998, 120, 7987–7988; https://doi.org/10.1021/ja980745t.Search in Google Scholar
7. Jurisson, S., Lydon, J. Potential technetium small molecule radiopharmaceuticals. Chem. Rev. 1999, 99, 2205–2218; https://doi.org/10.1021/cr980435t.Search in Google Scholar PubMed
8. Manicum, A., Smith, M. S., Alexander, O. T., Twigge, L., Roodt, A., Visser, H. G. First kinetic data of the CO substitution in fac-[Re(L,L′-Bid)(CO)3(X)] complexes by tertiary phosphines PTA and PPh3: synthesis and crystal structures of water soluble rhenium(I) tri- and dicarbonyl complexes with 1,3,5-triaza-7-phosphaadamantane (PTA). Inorg. Chem. Comm. 2019, 101, 93–98; https://doi.org/10.1016/j.inoche.2019.01.014.Search in Google Scholar
9. Bao, G., Mitragotri, S., Tong, S. Multifunctional nanoparticles for drug delivery and molecular imaging. Annu. Rev. Biomed. Eng. 2013, 15, 253–282; https://doi.org/10.1146/annurev-bioeng-071812-152409.Search in Google Scholar PubMed PubMed Central
10. Celardo, I., Pedersen, J. Z., Traversa, E., Ghibelli, L. Pharmacological potential of cerium oxide nanoparticles. Nanoscale 2011, 3, 1411–1420; https://doi.org/10.1039/c0nr00875c.Search in Google Scholar PubMed
11. De Jong, W. H., Borm, P. J. Drug delivery and nanoparticles: applications and hazards. Int. J. Nanomed. 2008, 3, 133–149; https://doi.org/10.2147/ijn.s596.Search in Google Scholar PubMed PubMed Central
12. Borm, P. J., Robbins, D., Haubold, S. The potential risks of nanomaterials: a review carried out for ECETOC. Part. Fibre Toxicol. 2006, 3, 11–13; https://doi.org/10.1186/1743-8977-3-11.Search in Google Scholar PubMed PubMed Central
13. Yazdani, A., Jansen, N., Banevicius, L., Czorny, S., Valliant, J. F. Imidazole-based [2+1] Re(I) / 99mTc complexes as isostructural nuclear and optical probes. Inorg. Chem. 2015, 54, 1728–1736; https://doi.org/10.1021/ic502663p.Search in Google Scholar PubMed
14. Ramoba, V. L., Alexander, T. O., Visser, H. G., Manicum, A. The crystal structure of fac-tricarbonyl (1,10-phenanthroline- κ2N,N′)-(pyrazole-κN) rhenium(I)nitrate, C18H12O3N4Re. Z. Kristallogr. NCS 2020, 235, 1203–1205; https://doi.org/10.1515/ncrs-2020-0249.Search in Google Scholar
© 2020 Mamolatelo J. Moremi et al., published by De Gruyter, Berlin/Boston
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