Vanadyl(acetylacetonate)2 mediated hydrolytic splitting of 1,3,5-triazine in a solution of toluene at 130 °C: The crystal structure of its axial formamide adduct European Journal of Chemistry 13 (2) (2022) 168-171 European Journal of Chemistry ISSN 2153-2249 (Print) / ISSN 2153-2257 (Online) – Copyright © 2022 The Authors – Atlanta Publishing House LLC – Printed in the USA. This work is published and licensed by Atlanta Publishing House LLC – CC BY NC – Some Rights Reserved. https://dx.doi.org/10.5155/eurjchem.13.2.168-171.2278 European Journal of Chemistry View Journal Online View Article Online Vanadyl(acetylacetonate)2 mediated hydrolytic splitting of 1,3,5-triazine in a solution of toluene at 130 °C: The crystal structure of its axial formamide adduct Evrim Arslan 1, Ivan Bernal 1,2 and Roger Lalancette 1,* 1 Carl A. Olson Memorial Laboratories, Department of Chemistry, Rutgers University, 73 Warren St., Newark, NJ, 07102, USA 2 Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, 2050 Johannesburg, ZA, South Africa * Corresponding author at: Carl A. Olson Memorial Laboratories, Department of Chemistry, Rutgers University, 73 Warren St., Newark, NJ, 07102, USA. e-mail: roger.lalancette@gmail.com (R. Lalancette). 10.5155/eurjchem.13.2.168-171.2278 Received: 22 March 2022 Received in revised form: 07 May 2022 Accepted: 08 May 2022 Published online: 30 June 2022 Printed: 30 June 2022 A toluene reaction of vanadyl bis(acetylacetonate) with 1,3,5-triazine produces a symmetrical three-fold hydrolytic cleavage of the triazine, and these three formamide moieties are found in the crystal structure. One of the resulting formamides attaches itself to the sixth (axial) position of the vanadyl complex, producing materials in which the remaining two formamides are trapped in the resulting lattice. Those crystals belong in space group Pca21, Z = 4 and the final R-factor = 0.030 for 3213 data collected at 100 K. Triazines Formamide X-ray diffraction Metal basic adduct Magnetic properties Vanadyl acetylacetonates Cite this: Eur. J. Chem. 2022, 13(2), 168-171 Journal website: www.eurjchem.com 1. Introduction Spectroscopic studies such as UV-Vis, electron spin resonance (ESR), etc. [1] have shown that good electron donor molecules (bases) such as pyridines, ketones, etc., can act as donors to vanadyl bis-acetyl acetonates, thereby perturbing its energy level sufficiently to serve as a useful measurement of the basicity of the donor molecules. Moreover, those studies also demonstrated that the phenomenon is solvent and temperature dependent in a measurable manner. Finally, since frequently the perturbing bases attach themselves permanently to the vanadyl moiety [1], they can be isolated in crystalline form and studied by X-ray diffraction. Guided by such observations, we decided to determine whether potential multiple donors would link together more than one vanadyl molecule in samples such as [(V=O)AcAc)2] Donor[(V=O)AcAc)2], etc., and found that, indeed, such a possi- bility already existed, as in (μ2-pyrimidine)-bis(bis(1, 1, 1, 5, 5, 5-hexafluoropentane-2,4-dionato)-oxo-vanadium(IV)) ADAHOC [2] and in (μ2-4-methylpyrimidine)-bis(bis(1, 1, 1, 5, 5, 5-hexa fluoropentane-2,4-dionato)-oxo-vanadium(IV))] ADAHUI [2], both of which used pyrimidines as the linker. Therefore, we decided to use 1,3,5-triazine as the bridge to ascertain whether such a linker could produce ternary vanadyl moieties. Unexpectedly, the procedure described below caused the symmetrical hydrolytic splitting of the triazine molecule, converting it into three formamide moieties, which, in turn, became (a) an axial ligand to the sixth position of the vanadyl moiety and (b) two cocrystallizing fragments in the isolated crystals, one of which was disordered over two positions. 2. Experimental 2.1. Materials Vanadyl(AcAc)2 and 1,3,5-triazine were purchased from Alfa-Aesar and were used without further purification. 2.2. Synthetic procedure and crystal growth We followed the preparation of the vanadyl(acac)2 complex given by Rowe and Jones [3], as follows: 0.500 g (1.89 mmoles) of vanadyl(AcAc)2 and 0.308 g (3.8 mmoles) of 1,3,5-triazine (2:1 mole ratio of ligand to vanadyl) were added to 45 mL of toluene in a sealed glass pressure cell and heated at 130 °C in a silicone oil bath for 1.5 hours, with stirring. ABSTRACT RESEARCH ARTICLE KEYWORDS https://dx.doi.org/10.5155/eurjchem.13.2.168-171.2278 https://www.eurjchem.com/ https://dx.doi.org/10.5155/eurjchem.13.2.168-171.2278 mailto:roger.lalancette@gmail.com http://www.eurjchem.com/ https://crossmark.crossref.org/dialog/?doi=10.5155/eurjchem.13.2.168-171.2278&domain=pdf&date_stamp=2022-06-30 Arslan et al. / European Journal of Chemistry 13 (2) (2022) 168-171 169 2022 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.13.2.168-171.2278 Table 1. Crystal data and details of the structure refinement for compound I. Crystal data Chemical formula C11H17NO6V, 2(CH3NO) Mr 400.28 Crystal system, space group Orthorhombic, Pca21 Temperature(K) 100(2) a, b, c (Å) 8.5017(2), 13.1292(3), 16.8795(4) V (Å3) 1884.10 (8) Z 4 Radiation Cu Kα μ (mm−1) 4.805 Crystal size (mm) 0.13 × 0.18 × 0.45 Data Collection Diffractometer Bruker APEX2 diffractometer Absorption correction numerical Tmin, Tmax 0.317, 0.650 No. of measured, independent and observed [I > 2σ(I)] reflections 16435, 3213, 3197 Rint 0.030 (sin θ/λ)max (Å−1) 0.605 Refinement R[F > 2σ(F)], wR(F), S 0.037, 0.088, 1.19 No. of reflections 3213 No. of parameters 241 No. of restraints 3 H-atom treatment Treated by a mixture of independent and constrained refinement Δρmax, Δρmin (e Å−3) 0.36, -0.37 Flack parameter 0.476(11) CCDC number 1557705 Computer programs: DIAMOND [6], SAINT [7], SADABS [7], APEX [8], SHELXT [10], SHELXL [11]. Figure 1. The formamide (N2O7) of crystallization (middle right) forms a strong cyclic dimer with the new axial formamide adduct (N1O6) to vanadium. In turn, its hydrogen bond to the disordered formamide (N3O8), ad infinitum, since (N1O6, middle left) begins a similar chain at left; this justifies the disorder of the N3 and N3A formamides, given that the hydrogen bonded propagation (up) by N3A hydrogens would otherwise disappear. The mixture was allowed to cool slowly, filtered through a sintered-glass funnel, and the filtrate was transferred to three 20 mL vials, whose openings were sealed with Parafilm through which was poked a number of small holes. The solutions were allowed to evaporate slowly. After a few days, the complex containing one formamide bound to the sixth site of the vanadyl complex and two formamides of crystallization was formed [C11H17NO6V· 2(CH3NO)]. At this stage, we do not know the mechanism whereby the three formamides were generated; however, since neither VO(AcAc)2 nor the toluene solvent contain nitrogen and the triazine was not protected from air and moisture, we speculate that water reacted with the 1,3,5- triazine at 130 °C and that was the source of the formamide molecule complexed to the vanadyl as well as those trapped as molecules of crystallization. 2.3. X-ray diffraction study, solution, and refinement of the data Crystals were taken directly from their mother liquor and immediately mounted on a Bruker-AXS SMART APEXII CCD diffractometer in a stream of nitrogen cooled to 100(1) K. The cell dimensions and the intensities were collected with Cu-Kα radiation (λ = 1.54178 Å). Data processing, Lorentz polari- zation, and face-indexed numerical absorption corrections were performed using SAINT, APEX, and SADABS computer programs [4-8]. After acquiring the 100 K datasets, the temperature of the crystal was slowly allowed to warm to room temperature, and the cell dimensions were the same as the 100 K cell, except for very slight elongations due to the higher temperatures. Crystal data and details of the structure refinement for the compound are given in Table 1. The following programs were used in this document and assigned reference numbers: (a) Cambridge Crystallographic Database, CCDC [4], (b) Mercury [5], (c) Diamond [6], (d) X-ray data collection, processing and refinement programs [7-11]. For convenience of the reader, henceforth we will refer to our compound by a six-character acronym used by the CCDC [4], such as ABCDEF, which can be used for direct access to the information contained in that database. 3. Results and discussion The contents of the asymmetric unit of the complex were not as predicted: a formamide molecule appeared as an axial ligand to the unchanged vanadyl reagent, and, whereas we had expected 1,3,5-triazine to bind 2 or even three vanadyl moieties together, we found instead that triazine had been hydrolytically cleaved symmetrically. 170 Arslan et al. / European Journal of Chemistry 13 (2) (2022) 168-171 2022 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.13.2.168-171.2278 Figure 2. Hydrogen-bonded network. Figure 3. The disorder of one formamide molecule, characterized by N3 and N3A. Of the three resulting formamides, one was bound to the vanadyl moiety and two appeared as crystallization molecules in the lattice. Figure 1 shows a useful fragment of the unit cell present in the compound. Figure 2 displays a larger portion of the crystalline lattice to illustrate the profusely hydrogen-bonded network created by the original vanadyl species, its formamide adduct, and the two formamides of crystallization. This network is obviously more extensive, since the depiction is only 2D; moreover, to avoid an unnecessary mess, we have not drawn all possible hydrogen bonds present in that fragment. The disorder of one formamide molecule is displayed in Figure 3. N3 and N3A illustrate the two- fold disorder at the C13-O8 formamide molecule of crystal- lization. By acting as a bridge between vanadyl O5 with the AcAc ligand O2, the entire lattice becomes infinitely hydrogen bonded, aided by additional hydrogen bonds provided by N1 and N2 hydrogens. We believe that the driving force for the disorder in the bridging formamide is the opportunity to form additional hydrogen bonds with adjacent vanadyl species. Note that the entire ensemble is asymmetric in that: (a) a hydrogen on N3 forms a hydrogen bond with O2 of the AcAc ligand; (b) another H on N3A forms a bond with the axial vanadyl V=O (O5). Several examples of formamide binding transition metal complexes are given in Supplementary Part I. Examples of the importance of triazine in a wide variety of fields are given in Supplementary Part II. Bond lengths and angles are given in Tables 4 and 5 in Supplementary Part III, and the H-atom positions are given in Table 6 in Part III as well. 4. Conclusions (a) Symmetrical cleavage of 1,3,5-triazine occurred while trying to prepare its vanadyl bis(acetylacetonate) triadduct in a toluene medium in a sealed container at 130 °C. The resulting species was unknown to date and contained a formamide in the axial position of (VO)(AcAc)2; (b) a method of evaluating the basicity of an organic donor (base) molecule can be obtained by ESR measurements of the displacement of the g-factor (and/or of the values of the hyperfine splitting constant, or both) of (VO)(AcAc)2 molecules in a “standard” solvent such as benzene or hexane which are nondonors (bases). Then, an useful scale of relative basicity of organic ligands may be obtained that way since ESR data yield highly precise values of both those quantities and the test requires only a few minutes (as long as they can enter the sphere of the vanadyl(AcAc)2 complex and perturb that system). Acknowledgements We acknowledge the National Science Foundation for NSF-CRIF Grant No. 0443538 for part of the purchase of the X-ray diffractometer. Supporting information CCDC-1557705 contains the supplementary crystallographic data for this article. These data can be obtained free of charge via https://www.ccdc.cam.ac.uk/structures/, or by e-mailing data_request@ ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44(0)1223-336033. The online version of this article contains supplementary material, which is available to authorized users. The reader can find (i) some particularly https://www.ccdc.cam.ac.uk/structures/ mailto:data_request@ccdc.cam.ac.uk mailto:data_request@ccdc.cam.ac.uk Arslan et al. / European Journal of Chemistry 13 (2) (2022) 168-171 171 2022 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.13.2.168-171.2278 attractive examples of formamides acting as ligands to various metals in Part I, and (ii) historic records for triazine compounds in Part II. Disclosure statement Conflict of interest: The authors declare that they have no conflict of interest. Ethical approval: All ethical guidelines have been adhered. Sample availability: Samples of the compounds are available from the author. CRediT authorship contribution statement Conceptualization: Evrim Arslan, Ivan Bernal, Roger Lalancette; Methodology: Evrim Arslan, Ivan Bernal, Roger Lalancette; Writing - Original Draft: Evrim Arslan, Ivan Bernal, Roger Lalancette; Writing - Review and Editing: Evrim Arslan, Ivan Bernal, Roger Lalancette; Visualization: Evrim Arslan, Ivan Bernal, Roger Lalancette. ORCID and Email Evrim Arslan evrim.arslan1@gmail.com https://orcid.org/0000-0001-9712-3573 Ivan Bernal bernalibg@gmail.com https://orcid.org/0000-0002-8168-5907 Roger Lalancette roger.lalancette@gmail.com https://orcid.org/0000-0002-3470-532X References [1]. Bernal, I.; Rieger, P. H. Solvent effects on the optical and electron spin resonance spectra of vanadyl acetylacetonate. Inorg. Chem. 1963, 2, 256–260. [2]. Ishida, T.; Mitsubori, S.-I.; Nogami, T.; Takeda, N.; Ishikawa, M.; Iwamura, H. Ferromagnetic exchange coupling of vanadium(IV) dπ spins across pyrimidine rings: Dinuclear complexes of oxovanadium(IV) bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionate) bridged by pyrimidine derivatives. Inorg. Chem. 2001, 40, 7059–7064. [3]. Bryant, B. E.; Fernelius, W. C.; Busch, D. H.; Stoufer, R. C.; Stratton, W.; Rowe, R. A.; Jones, M. M. Vanadium(IV) Oxy(acetylacetonate). In Inorganic Syntheses; John Wiley & Sons, Inc.: Hoboken, NJ, USA, 2007; pp. 113–116. [4]. Groom, C. R.; Bruno, I. J.; Lightfoot, M. P.; Ward, S. C. The Cambridge Structural Database. Acta Crystallogr. B Struct. Sci. Cryst. Eng. Mater. 2016, 72, 171–179. [5]. Macrae, C. F.; Edgington, P. R.; McCabe, P.; Pidcock, E.; Shields, G. P.; Taylor, R.; Towler, M.; van de Streek, J. Mercury: visualization and analysis of crystal structures. J. Appl. Crystallogr. 2006, 39, 453–457. [6]. Brandenburg, K.; Putz, H. DIAMOND. Crystal Impact GbR, Bonn, Germany, 1999. [7]. Bruker SAINT, SADABS, 2009 Bruker AXS Inc., Madison, Wisconsin, USA. [8]. Bruker APEX 2, Version 2.0-2. 2009 Bruker AXS Inc., Madison, Wisconsin, USA. [9]. Sheldrick, G. M. A short history of SHELX. Acta Crystallogr. A 2008, 64, 112–122. [10]. Sheldrick, G. M. SHELXT - integrated space-group and crystal- structure determination. Acta Crystallogr. A Found. Adv. 2015, 71, 3– 8. [11]. Sheldrick, G. M. Crystal structure refinement with SHELXL. Acta Crystallogr. C Struct. Chem. 2015, 71, 3–8. Copyright © 2022 by Authors. This work is published and licensed by Atlanta Publishing House LLC, Atlanta, GA, USA. The full terms of this license are available at http://www.eurjchem.com/index.php/eurjchem/pages/view/terms and incorporate the Creative Commons Attribution-Non Commercial (CC BY NC) (International, v4.0) License (http://creativecommons.org/licenses/by-nc/4.0). By accessing the work, you hereby accept the Terms. 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Permissions for commercial use of this work beyond the scope of the License (http://www.eurjchem.com/index.php/eurjchem/pages/view/terms) are administered by Atlanta Publishing House LLC (European Journal of Chemistry). mailto:evrim.arslan1@gmail.com https://orcid.org/0000-0001-9712-3573 mailto:bernalibg@gmail.com https://orcid.org/0000-0002-8168-5907 mailto:roger.lalancette@gmail.com https://orcid.org/0000-0002-3470-532X http://www.eurjchem.com/index.php/eurjchem/pages/view/terms http://creativecommons.org/licenses/by-nc/4.0 http://www.eurjchem.com/index.php/eurjchem/pages/view/terms 1. Introduction 2. Experimental 2.1. Materials 2.2. Synthetic procedure and crystal growth 2.3. X-ray diffraction study, solution, and refinement of the data 3. Results and discussion 4. Conclusions Acknowledgements Supporting information Disclosure statement CRediT authorship contribution statement ORCID and Email References PrintField10: PrintField11: PrintField12: PrintField13: PrintField20: PrintField21: PrintField22: PrintField23: