Synthesis and structures of yttrium(III) complexes containing 2-Naphthoyltrifluoroacetone, benzoyltrifluoroacetone and n,n-dimethyl-n’-(9-methylanthracenyl)ethylenediamine ligand

3 HNUE JOURNAL OF SCIENCE Natural Sciences, 2020, Volume 65, Issue 4A, pp. 3-10 This paper is available online at SYNTHESIS AND STRUCTURES OF YTTRIUM(III) COMPLEXES CONTAINING 2-NAPHTHOYLTRIFLUOROACETONE, BENZOYLTRIFLUOROACETONE AND N,N-DIMETHYL-N’-(9-METHYLANTHRACENYL)ETHYLENEDIAMINE LIGAND Dinh Thi Hien1* and Phan Thi Thu Ha2 1The Faculty of Chemistry, Hanoi National University of Education 2The Faculty of Natural Science, Tay Nguyen University Abstract. The synthesis and structures of yttrium(III) complexes containing 2- naphthoyltrifluoroacetone (HTFNB); benzoyltrifluoroacetone (HTFPB) and N,N-dimethyl- N’-(9-methylanthracenyl)ethylenediamine (AnMe2) ligand are reported. The complexes have been characterized by IR, 1H NMR and single-crystal X-ray diffraction studies. The crystal structure of Y(TFNB)3AnMe2 (C3) and Y(TFPB)3AnMe2 (C4) were determined. X-ray crystallographic analysis demonstrates that in the mononuclear complex C3, C4, the Y3+ ion was coordinated by three TFNB/TFPB ligands and one ancillary ligand AnMe2. Keywords: lanthanidecomplexes;β-Diketonate; X-ray structure. 1. Introduction β-Diketonates are a family of the most widely investigated ligands in lanthanide complexes. They usually occur as keto-enol tautomerisms, in solutions and in solids, as evidenced by solution 1H NMR spectroscopy and single-crystal X-ray diffraction analyses. The β-diketonates havebeenrecognizedasefficientsensitizers,socalled“antennae’’, to achieving high harvest lanthanide emissions, owing to the effectiveness of the energy transfer from theβ-diketonate to the Ln3+ cation. Thus this family of complexes have developed rapidly, and attracted long-lasting interest because of their promising prospects in widespread applications, ranging from materials science to biomedical analysis [1-6]. The structural characterization plays an important role in the development of the chemistry of β-diketonate lanthanide complexes. For the purpose of probing the formation and structure of the rare earth complexes with β-diketonate ligands and auxiliary ligand containing anthracene substituent. In the following discussions, the main attention will be focused on the synthesis and structures of yttrium(III) complexes containing 2-naphthoyltrifluoroacetone (HTFNB); benzoyltrifluoroacetone (HTFPB) and N,N-dimethyl-N’-(9-methylanthracenyl)ethylenediamine ligand (AnMe2). 2. Content 2.1. Experiments 2.1.1. Synthesis of Y(TFNB)3(H2O)2 complex (C1) Received April 6, 2020. Revised April 27, 2020. Accepted May 7, 2020 Contact Dinh Thi Hien, e-mail address: dth0104@gmail.com Dinh Thi Hien and Phan Thi Thu Ha 4 Y2O3 (0.0452 g, 0.2 mmol) was dissolved in HCl at 50oC, then distilled water was added and heated at 100oC (1). A solution of NaOH (0.048 g, 1.2 mmol) and HTFNB (0.3192 g, 1.2 mmol) in MeOH (15 mL) was added drop-wise under stirring to a solution of 1 in MeOH (15 mL). The mixture was stirred at room temperature until affording a white solid. The product was washed by a large amount of CCl4 and air-dried. Yield: 75%. 2.1.2. Synthesis of Y(TFPB)3(H2O)2 complex (C2) Y2O3 (0.0452 g, 0.2 mmol) was dissolved in HCl at 50oC, then distilled water was added and heated at 100oC (2). A solution of NaOH (0.048 g, 1.2 mmol) and HTFPB (0.2592 g, 1.2 mmol) in MeOH (15 mL) was added drop-wise under stirring to a solution of 2 in MeOH (15mL). The mixture was stirred at room temperature until affording a white solid. The product was washed by a large amount of CCl4 and air-dried. Yield: 95%. 2.1.3. Synthesis of N,N-Dimethyl-N′-(9-methylanthracenyl)ethylenediamine (L) Asolution of anthracene-9-caboxaldehyde (0.206 g; 1 mmol) in EtOH (50 mL) was added N,N-dimethylethylenediamine (0.12 mL; 1.1 mmol), then it was let to react for 36 hours at room temperature with constant stirring. Solid NaBH4 (0.2 g) was added and the mixture was heated at 60oC to reflux for 4 hours to reduce the Schiff base formed.2 After removal of the solvent, the pale yellow solid remained and the solution was stirred with water (50 mL) for 60 minutes and extracted with CH2Cl2 (20 mL). The organic layer was evaporated to dryness whereupon L was obtained as a brown semisolid. Yield: 87% 2.1.4. Synthesis of Y(TFNB)3AnMe2 complex (C3) A solution of AnMe2 (1mmol) in CHCl3 (15mL) was added drop-wise under stirring to a solution of C1 in MeOH (15 mL). The mixture was stirred at room temperature about 1 hour until having yellowish precipitant. The solvent was removed in vacuum and the resulting solid washed with n-hexane. After drying in vacuum, a pale yellow powder was obtained. The solid obtained was crystallized in EtOH and CH2Cl2 (V:V = 1:1). Yield: 74% Synthesis and structures of Yttrium(III) complexes containing 2-naphthoyltrifluoroacetone 5 2.1.5. Synthesis of Y(TFPB)3AnMe2 complex (C4) is the same process as C3 Yield: 72 % 2.2. Methods The IR spectra of C3, C4 were measured with a FT-IR 8700 infrared spectrophotometer (4000 – 400 cm–1) in KBr pellets. The 1H NMR spectra of the complexes were recorded with a Bruker-500MHz spectrometer in CDCl3 at 298K. Single–crystal X–ray diffraction data of the complex C3, C4 was measured on the X–ray diffractometer (Bruker D8 Quest) at 298K at the Faculty of Chemistry, Hanoi National University. Structure solution and refinement were performed with OLEX2 programs. 2.3. Results and discussion 2.3.1. Infrared spectroscopy The infrared spectra of the complexes Y(TFNB)3AnMe2 and Y(TFPB)3AnMe2 are shown in Figures 1 and 2. Figure 1. The infrared spectrum of Y(TFNB)3AnMe2 complex Dinh Thi Hien and Phan Thi Thu Ha 6 Figure 2. The infrared spectrum of Y(TFPB)3AnMe2 complex The IR spectra of C1, C2 all show characteristic broad bands in the 3000–3500 cm–1 region, which are in line with the presence of the water coordinated to the ion Y3+.3 The disappearance of the bands in the IR spectra of C3, C4 confirm that the water molecules were displaced by AnMe2 ligands. The bands near 1611 - 1614 cm-1 are due to C=O stretch of HTFNB and HTFPB coordination. ThechangeinabsorptionfrequencyofνC=O compared with free ligand and the emergence of νM-N absorption in the low frequency proved HTFNB; HTFPB and AnMe2 ligand were coordinated with Y(III). In addition, the absorption band at the 470 - 472 cm-1 region in the composite complex confirms the complexation of Y3+ ion with AnMe2 ligand through nitrogen atoms. 2.3.2. Nuclear magnetic resonance spectroscopy We researched the structure of C3, C4 by 1H NMR spectroscopy to determine the structures more accurately. The 1H NMR spectra of C3, C4 are shown in Figures 3 and 4, the signals attribution 1H NMR spectra of the two C3 and C4 are shown in Table 1. Table 1. The signals attribution 1H NMR spectra of the two C3 and C4 S.No σ(ppm) Signals Integral Symbol Y(TFNB)3AnMe2 1 2.1 Singlet 1.8 2H (Hd) 2 2.4 Singlet 5.98 6H (Hb, Hc) 3 3.0 Doublet 1.71 2H (He) 4 3.4 Singlet 1.97 2H (Hg) 5 5.3 Singlet 0.85 1H (Hf) 6 6.7 Singlet 3.0 3H (Ha) 7 7.3 Triplet 3.17 3H (H6’) 8 7.5 Multiple 10.26 10H (H5’, H7’, H2, H3, H6, H7) 9 7.7 Doublet 3.07 3H (H3’) 10 7.8 Doublet 3.05 3H (H8’) 11 8.0 Multiple 5.14 5H (H4’, H4, H5) 12 8.4 Singlet 1.03 1H (H10) 13 8.5 Multiple 5.05 5H (H1’, H1, H8) Y(TFPB)3AnMe2 1 2.1 Singlet 1.81 2H (Hd) 2 2.3 Singlet 6.13 6H (Hb, Hc) Synthesis and structures of Yttrium(III) complexes containing 2-naphthoyltrifluoroacetone 7 3 2.9 Singlet 1.61 2H (He) 4 3.3 Singlet 1.98 2H (Hg) 5 5.2 Singlet 0.85 1H (Hf) 6 6.6 Singlet 3.00 3H (Ha) 7 7.3 Triplet 6.13 6H (Hp) 8 7.5 Multiple 7.09 7H (Hm, H2, H3, H6, H7) 9 7.9 Doublet 6.05 6H (Ho) 10 8.0 Multiple 1.99 2H (H4, H5) 11 8.4 Doublet 2.99 3H (H1, H8, H10) On the 1H NMR spectra of C3, C4, the signals at 2.1 ÷ 5.3 ppm characterized the protons of the AnMe2 ligand. The signals at 6.6 and 6.7 characterized the methine protons of diketonate moiety of HTFNB and HTFPB ligands respectively. There was some overlap between the signals of the phenyl of C1 and the naphthalene of C2 with anthracene, the signals from 7.3 to 8.5 ppm characterized the proton of the aromatic rings. Figure 3. The 1H NMR spectrum of Y(TFNB)3AnMe2 complex Dinh Thi Hien and Phan Thi Thu Ha 8 Figure 4. The 1H NMR spectrum of Y(TFPB)3AnMe2 complex 2.3.3. Single-crystal X-ray diffraction The structures of C3, C4 were determined by single crystal X-ray diffraction (Figure 5). Selected bond lengths and angles are provided in Table 2. Crystal data and data collection parameters for the complexes are given in Tables 3 and 4. Table 2. Selected bond lengths /Å and angles /° for complexes C3, C4 C3 C4 Y – O1 2.283(3) 2.276(3) Y– O2 2.333(3) 2.355(3) Y – O3 2.297(4) 2.328(3) Y – O4 2.327(4) 2.324(3) Y – O5 2.346(4) 2.353(3) Y – O6 2.325(4) 2.291(3) Y – N1 2.571(4) 2.566(4) Y – N2 2.605(4) 2.611(4) O1–Y–O2 73.09(12) 72.76(11) O3–Y–O4 71.46(13) 71.25(12) O5–Y–O6 70.49(12) 70.91(12) N1–Y–N2 69.01(13) 69.21(12) Synthesis and structures of Yttrium(III) complexes containing 2-naphthoyltrifluoroacetone 9 Figure 5. Molecular structure of compound C3, C4 in the crystal. Color scheme: Y, blue; N, pale blue; O, red; F, pale green; C, gray; H, white Table 3. Crystal data and structure refinement for complexes C3, C4 C3 C4 Formula C61H46F9N2O6Y C49H40F9N2O6Y Mw/g.mol–1 1163.95 1013.76 Crystal system monoclinic monoclinic a/Å 10.0705(7) 12.5572(5) b/Å 20.3983(15) 16.6789(7) c/Å 28.601(2) 23.0920(10) α/° 90 90 β/° 97.024(2) 103.3960(10) γ/° 90 90 Volume/Å3 5831.2(7) 4704.8(3) Space group P21/c P21/c Z 4 4 ρcalcg/cm3 1.3246 1.4297 μ/mm–1 1.090 1.339 Reflections collected 73703 81604 Independent reflections 10697 [Rint = 0.1039, Rsigma = 0.0559] 9650 [Rint = 0.1762, Rsigma = 0.0706] Data/restraints/parameters 10697/0/714 9650/0/606 R1/wR2[I>=2σ(I)] R1 = 0.0572, wR2 = 0.1599 R1 = 0.1167, wR2 = 0.1532 GOF 0.924 1.114 C3 C4 Dinh Thi Hien and Phan Thi Thu Ha 10 The structure of the C3, C4 complexs reveal a coordination number of eight for central metal ion, in which Y(III) are bonded to six oxygen atoms from three TFPB ligands and two nitrogen atoms from the AnMe2 ligand. The bond lengths of Y1-O are 2.27−2.35 Å. The bond lengths of Y(III) with two nitrogen atoms of AnMe2 N are 2.55 Å and 2.61 Å. The O-Y-O bond angles are nearly the same and in the range of 70−720, the bond angles of the N-atoms in the AnMe2 with Y(III) are 700. The bond lengths and angles are similar to reported values [3]. The C-N= bond lengths (1.496−1.504 Å) in the complex was found longer than that of O-N (1.472 Å) and within the range of metal complexes with AnMe2 ligand [3]. It might be due to the delocalization of π electrons among the diketonate moiety and naphthalene ring upon complexation. In the Y(III) complexes, the C-C bond length in the diketone of the C3, C4 complexes are shorter than the C-C bond length (1.54 Å) but longer than that of C=C (1.34 Å). Similarly, the C-O bond length in the diketone of the C3, C4 complexes are also shorter than the length of the C-O but longer than the bond length of C=O. Thisconfirmsthedelocalizationofπelectronsin the β-diketonate upon Y(III) and TFPB/ TFNB ligand complexation. 3. Conclusions Two Yttrium(III) complexes with TFNB and TFPB ligands were synthesized with the ancillary ligands. The structures of these complexes were defined by physical methods. The results confirmed that the two C3, C4 are mononuclear complexes with three TFNB (or TFPB) ligands and one ancillary ligand (AnMe2). Acknowledgement. This work was completed with financial support from the Ministry of Education and Training of Vietnam, under the project B2018-SPH- 49. REFERENCES [1] Chun-Hui Huang, 2010. Rare Earth Coordination Chemistry: Fundamentals and Applications. Peking University, Beijing. [2] Bamaprasad Bag and Parimal K. Bharadwa, 2005. Perturbation of the PET Process in Fluorophore-Spacer-Receptor Systems through Structural Modification: Transition Metal Induced Fluorescence Enhancement and Selectivity. J. Phys. Chem. B, 109, p. 4377-4390. 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