crystals Article Synthesis, Characterization, and Crystal Structure of a Triazine Anion Pentafluoroosmium(VI) Complex Monther A. Khanfar 1,* ID , Basem F. Ali 2,3 ID , Hashem Shorafa 4 and Konrad Seppelt 4 1 Department of Chemistry, The University of Jordan, Amman 11942, Jordan 2 Department of Chemistry, King Faisal University, Al-Ahssa, Hufof 31982, Saudi Arabia; [email protected] or [email protected] 3 Department of Chemistry, Al al-Bayt University, Mafraq 25113, Jordan 4 Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 34/36, 14195 Berlin, Germany; [email protected] (H.S.); [email protected] (K.S.) * Correspondence: [email protected]; Tel.: +962-6-5355-000 Received: 11 December 2017; Accepted: 23 January 2018; Published: 29 January 2018 Abstract: The synthesis and characterization of a novel triazine anion pentafluoroosmium(VI) complex are presented. The single crystal determination of the title compound (hereafter denoted 1) ◦ was carried out at −140 C. Compound 1,C3F4N3OsF5, crystallizes in the monoclinic space group, ◦ P21/n, with unit cell dimensions: a = 8.6809(17) Å, b = 7.6848(15) Å, c = 12.415(3) Å, β = 102.633(4) , V = 808.2(3) Å3, and Z = 4. Synthesis, characterization, X-ray diffraction study along with the crystal supramolecular analysis of the title complex were carried out. The complex contains the − anionic triazine unit C3N3F4 acting as a mono dentate ligand to osmium(VI) with five fluoro ligands in a slightly distorted octahedral geometry around osmium(VI) ion (osmium is denoted − as Os). The C3N3F4 , triazine anion ring deviates from planarity, only with the C1 being tetrahedral. The crystal lattice of the title compound displays significant intermolecular X···X interactions, namly F···F, F···N and F···C. All types of X···X bonding consolidate to form a three-dimensional network. Keywords: triazine anion; crystal structure; fluoroosmium(VI) complexes; supramolecular crystal; F···F; F···N; F···C intermolecular interactions 1. Introduction The employment of osmium(VI) fluoride/antimony(V) fluoride (OsF6/SbF5) as a powerful oxidizing agent to break the aromaticity of benzene to form radical benzene cations was established some time ago [1]. This distorted radical cation was characterized using X-ray structural analysis [1]. However, the isolation of the benzene radical cation is a challenge. Seppelt and co-workers obtained + − + − the compoundsC6F6 Os2F11 and C6F6 Sb2F11 [1,2]. The synthesis and crystal structure of other substituted benzene cations such as aniline radical cation [3] and radical cation of monocyclic arenes [4,5] have also been reported. Further research was directed toward the formation of stable radicals for several organic systems [6–9]. On the other hand, fluorine-containing compounds are important for life and material sciences [10–12]. Fluorine is comparable to hydrogen atom in size but, possesses different physical and chemical properties, and capable of forming strong halogen bonds [13–19]. The latter can be of different motifs, such as F···F, F···N, and F···C intermolecular interactions. In an attempt to use other aromatic species in a manner similar to benzene, we encountered the 2,4,6-trifluoro-1,3,5-triazene ligand (Figure1). It was expected that this system would proceed easily to form a radical cation compared to benzene, but a pentafluoroosmium(VI)-complex containing − C3N3F4 ligand was detected instead. In this report, we are disclosing the successful synthesis, single crystal X-ray diffraction and crystal supramolecularity of this system. Crystals 2018, 8, 63; doi:10.3390/cryst8020063 www.mdpi.com/journal/crystals CrystalsCrystals2018 2018, 8, ,8 63, x FOR PEER REVIEW 2 of2 of 9 8 Figure 1. The chemical structure of 2,4,6-trifluoro-1,3,5-triazene ligand. Figure 1. The chemical structure of 2,4,6-trifluoro-1,3,5-triazene ligand. 2. Materials and Methods 2. Materials and Methods The compound is unstable at room temperature and sensitive to moisture. Therefore, IR and UV Thespectra compound could not is unstable be recorded. at room Raman temperature spectra and showed sensitive strong to moisture. fluorescence Therefore, in all IRcases. and Yield UV spectracould only could be not estimated be recorded. by the Raman amount spectra of colored showed crystalline strong material, fluorescence often in in all mixtures cases. Yield of colorless could onlycrystals, be estimated which were by the possibly amount a ofstarting colored material. crystalline material, often in mixtures of colorless crystals, which were possibly a starting material. Caution: Handling SbF5 and OsF6 requires eye and skin protection. Caution: Handling SbF and OsF requires eye and skin protection. The following reagents5 were purchased6 from the indicated vendor: C3N3F3 (Sigma-Aldrich The following reagents were purchased from the indicated vendor: C N F (Sigma-Aldrich Chemie GmbH), SbF5 (Fluorochem Ltd.), NH4F (E. Merck), CF3COOH (Merck3 3 3 Schuchardt). The Chemietriazine GmbH), was checked SbF5 (Fluorochem by NMR Ltd.),spectroscopy NH4F (E. for Merck), purity. CF3 COOHThe solvent (Merck sulfuryl Schuchardt). fluoride The triazinechloride was checked by NMR spectroscopy for purity. The solvent sulfuryl fluoride chloride (SO ClF) was (SO2ClF) was prepared by treating a mixture of thionyl chloride (SO2Cl2) and ammonium2 fluoride prepared by treating a mixture of thionyl chloride (SO Cl ) and ammonium fluoride (NH F) with (NH4F) with trifluoroacetic acid (CF3COOH) [20]. SbF2 5 was2 vacuum distilled twice using4 a glass trifluoroaceticvacuum line acidwith (CF a −330COOH) °C trap. [20 ].The SbF resulting5 was vacuum liquid distilled was clea twicer, colorless, using a and glass highly vacuum viscous. line with The a −30 ◦C trap. The resulting liquid was clear, colorless, and highly viscous. The compound OsF compound OsF6 was obtained via a reaction of Os powder and F2 in Monel autoclaves at 300 °C [21].6 ◦ wasReagents obtained and via starting a reaction materials of Os must powder be highly and F2 purein Monel since autoclavescontaminants at 300are oxidizedC[21]. Reagents preferentially. and startingReactions materials were performed must be highly in PFA pure (Poly since perfluorov contaminantsinylether are oxidized tetrafluoroethylene preferentially. copolymer) Reactions weretubes; performed in PFA (Poly perfluorovinylether tetrafluoroethylene copolymer) tubes; volatile materials volatile materials (anhydrous SO2ClF, OsF6) were handled in a stainless-steel vacuum line. (anhydrous SO ClF, OsF ) were handled in a stainless-steel vacuum line. OsF6 (1002 mg) and6 SO2ClF (2 mL) were condensed in a PFA tube containing SbF5 (50 mg). The mixtureOsF6 was(100 allowed mg) and to SO warm2ClF to (2 0 mL) °C to were ensure condensed a homogenous in a PFA mixture. tube containing The mixture SbF was5 (50 cooled mg). The mixture was allowed to warm to 0 ◦C to ensure a homogenous mixture. The mixture was again with the aid of liquid nitrogen. C3N3F3 (100 mg) was condensed into the cooled mixture. The cooledmixture again was with then the allowed aid of liquidto warm nitrogen. very slowly C3N3F to3 (100 −30 mg)°C, a wasffording condensed a yellow into clear the cooledsolution. mixture. At −30 The mixture was then allowed to warm very slowly to −30 ◦C, affording a yellow clear solution. °C, the excess C3N3F3 and other volatiles were removed under vacuum. After that, SO2ClF (2 mL) ◦ Atwas−30 condensedC, the excess in a PFA C3N tube.3F3 and Recrystallization other volatiles from were − removed30 °C to − under78 °C a vacuum.fforded yellow After that,crystals. SO2 ClFCare ◦ ◦ (2must mL) be was taken condensed to ensure in that a PFA the temperature tube. Recrystallization never exceeds from −30− °C30 throughoutC to −78 theC affordedentire procedure. yellow ◦ crystals.Single Care crystal must befor taken X-ray to diffraction ensure that was the temperatureperformed on never a Bruker-AXS, exceeds −30 D8C throughoutventure, photon the entiredetector, procedure. tube: incotec microfokus (Mo Kα radiation, Bruker, Germany) under oxygen- and moisture-freeSingle crystal conditions for X-ray at diffraction temperatures was performedbelow −100 on °C a using Bruker-AXS, a special D8 device venture, of photonlocal design detector, [22]. tube:All data incotec collections microfokus were (Mo performed Ka radiation, at −140 Bruker, °C. After Germany) semiempirical under oxygen- absorption and corrections, moisture-free the ◦ conditionsstructure atwas temperatures solved by belowdirect −methods100 C usingand refined a special using device the of program local design SHELXTL [22]. All [23,24]. data ◦ collectionsNon-hydrogen were performedatoms were at −refined140 C. anisotropically; After semiempirical H atoms absorption were re corrections,fined isotropically. the structure Relevant was solveddata collection by direct methodsand refinement and refined parameters using the are program listed in SHELXTL Table 1. [23,24]. Non-hydrogen atoms were refinedCrystallographic anisotropically; data H atoms in cif were format refined have isotropically. been deposited Relevant with the data Cambridge collection andCrystallographic refinement parametersData Center are (CCDC listed in1508189). Table1. Copies of the data can be obtained free of charge from The Director, CCDC,Crystallographic 12 Union dataRoad, in cifCambridge, format have beenCB2 deposited1EZ, UK, with fax: the Cambridge+44 1223 Crystallographic366033, email: [email protected] Center (CCDC 1508189). or on Copiesthe web of at the http://www.ccdc.cam.ac.uk.