Synthesis, crystal structure, vibrational studies, optical properties and DFT calculation of a new luminescent material based Cu (II)
Abstract
In this work, we report the synthesis, molecular structure, the vibrational spectral (FT-IR, FT-Raman) analysis and optical properties of the investigated novel non linear optical bis(2, 2, 6, 6– Tetramethylpiperidinium–1–yl) oxidanyl tetrachlorocuprate (II), having a general chemical formula (C9H19NO)2 [CuCl4] abbreviated as (TEMPO-H)2 [CuCl4]. The molecular structure crystallises in the orthorhombic system with the P212121 space group. The crystalline stability is installed by a zero-dimensional network using hydrogen bonds between O
H⋯Cl, NH⋯Cl and CH⋯O. In addition, a 3-D Hirshfeld surface analysis was performed to study molecular interactions and connect them with 2-D fingerprint schemes to detect the relative contribution of these interactions to the crystalline structure. Molecular structure, vibrating wave number, non-linear optical characterization (NLO), and Mulliken were calculated with B3LYP/LanL2DZ (DFT the Density Functional Theory) using GAUSSIAN09. The optimized geometry and the vibrational spectra calculated results compared to experimental data, showed a good overall agreement. The UV–Visible absorption and the photoluminescence (PL) spectroscopy of (TEMPO–H)2 [CuCl4] were also presented. The unaided-eye-detectable blue luminescence emission comes from the excitonic transition in the CuCl4 anions. Finally, the electronic property was determined by time-dependent DFT (TD-DFT) approach.
Introduction
In recent years, the design and synthesis of inorganic organic solids that rely on the concept of crystal engineering have attracted considerable attention regarding the application of these compounds. Recently, various applications have been recorded owing to their significant magnetic, luminescence, nonlinear optical (NLO), catalytic, electrical and ferroelectric properties [[1], [2], [3], [4], [5]]. More specifically, the development of photonic and optoelectronic technologies depends largely on the growth of NLO materials with high non-linear optical responses and the emergence of novel and more efficient materials [6]. Organometallic compounds such as NLO are particularly important in terms of their ability to provide significant opportunities to combine the beneficial properties of inorganic materials, which in turn provide good conductivity, mechanical and thermal stability, amplitude, magnetic displacements or insulation, structural diversity, ease of processing, high NLO coefficients and efficient fluorescence.
For this reason, considerable efforts have been performed to synthesize a new organic-inorganic material (TEMPO-H)2 [CuCl4], which crystallizes in non centrosymmetric space group showing enhanced NLO activity. On the other side, copper (II) possesses an association of different dimensional orders: zero (0D), one (1D), two (2D) or three (3D) dimensional networks [[7], [8], [9], [10], [11]]. In other words, the Cu2+ ion can acquire a variety of coordination numbers and geometries: tetrahedral [12], trigonal bipyramidal [13] square pyramidal, and octahedral [14] in view of the relative flatness of the potential surfaces and the presence of a d9 electronic system proving the presence of Jahn–Teller effect in this complex [15]. The crystallographic study is an important source that can be used to derive information about the intermolecular interactions involved in the crystal packing [16,17]. In addition, the application of Hirshfeld surface analysis is increasing in the field of crystallography. This approach has also become an intrinsic tool for the investigation of intermolecular interactions in the crystal packing. Research on copper coordination compounds, structural properties as well as vibrational and non-linear optical (NLO) properties with DFT calculations using the theoretical level B3LYP/LanL2DZ for new hybrid materials, was carried out in order to determine physic-chemical properties as well as energy gap of materials. The ultimate objective is the investment of these properties for technological applications. Having the motivations stated above and encouraged by this pioneering work, we attempt to present a novel hybrid compound (TEMPO-H)2 [CuCl4]. Our central focus is upon the crystal structure which is characterized by X-ray diffraction as well as vibrational spectra study (Raman and infrared spectroscopy) and optical properties studies (absorption and photoluminescence). In the light of our theoretical calculations, the relationship between vibrational spectra and calculated results makes it possible to clearly identify vibration models and better understand the binding and structural features of hybrid compounds, the theoretical study of others, the characteristics of linearity and the excessive priority of the mixture. Functional Density Theory (DFT/B3LYP/LanL2DZ) is the basis of all calculations. After all, TD-DFT calculations were also carried out in order to analyze the electronic property which was investigated and interpreted.
Section snippets
Synthesis
(TEMPO-H)2 [CuCl4] single crystals were synthesized through the reaction in stoichiometric 1:2 amounts of Cupper (II) chloride (CuCl2) anhydrous and (2,2,6,6-Tetramethylpiperidin-1-yl) oxidanyl (C9H18NO): (TEMPO). First, (TEMPO) solution dissolved in an aqueous solution of HCl (37%) was added to the solution of anhydrous Cupper (II) chloride in anhydrous ethanol. Several weeks after, yellow plate-shaped crystals of very high quality were obtained by evaporation at room temperature. The dried
Structure description
X-ray single crystal diffraction was used for the identification of the synthesized compound. It revealed that the (TEMPO-H)2 [CuCl4] compound crystallizes in the orthorhombic system with a non-centrosymmetric space group P212121. The dimensions of the cell are as follows: a = 11.911 (18), b = 11.911 (10), c = 17.832 (4) Å, V = 2530.0 (7) Å3 with four formula units in unit cell (Z = 4). The asymmetric unit of the structure drawn with 20% probability thermal ellipsoids, together with the atomic
Absorption and photoluminescence spectra
The electronic structure of the molecule in ground state can be determined by the wave function of the electron moving within the molecule [45]. The absorption spectroscopy was carried out according to the Frank–Condon principle, which allows studying electronic transitions.
Fig. 11, Fig. 12, show the superposition of the experimental and theoretical UV–Visible absorption spectra and the photoluminescence spectrum of the (TEMPO–H)2 [CuCl4] at room temperature, respectively.
As a matter of fact,
Conclusions
We have synthesized a new NLO material (TEMPO–H)2 [CuCl4]. It crystallizes in an orthorhombic system with a non–centrosymmetric space group P212121. The crystalline packing of the compound is stabilized by hydrogen bonding interactions OH⋯Cl and CH⋯Cl. Thus, the analysis of the Hirschfield surface in the form of decomposed fingerprint plots allowed a quantitative examination showing the intermolecular interactions in the structure. Based on DFT calculations, the geometry and vibration spectrum
Acknowledgements
The authors thank the members of unit of common services, at the University of Sfax for their assistance in the measurements for X–ray diffraction. The authors are also grateful to Prof Hamadi KHEMAKHEM, for his cooperation in the Raman spectroscopy measurement.
References (52)
- et al.
J. Mol. Struct.
(2013) - et al.
J. Physica B.
(2012) - et al.
J. Mol. Struct.
(2012) - et al.
J. Mol. Struct.
(2014) - et al.
J .Inorg. Chem. Acta
(2014) - et al.
J. Solid State Commun.
(2010) - et al.
J. Polyhedron.
(2013) - et al.
J. Coord. Chem.Rev
(2007) - et al.
J. Coord. Chem. Rev.
(2008) - et al.
J. Chem. Phys. Lett.
(1997)
J. Spectrochim. Acta A.
J. Spectrochim. Acta A.
J. Spectrochim. Acta A.
J. Physica E.
J. Mol. Struct.
J. Spectrochim. Acta A.
J. Spectrochim. Acta A
J. Lumin.
J. Spectrochim. Acta A.
Spectrochim. Acta A.
J. Phys. Chem. B
J. Inorg. Organomet. Polym. Mater.
J. Acta Crystallogr. E.
J. Supercond. Nov. Magnetism
J. Cluster Sci.
J. Acta. Crystallogr. E.
Cited by (11)
Crystal structure, Hirshfeld surface analysis, Vibrational studies, Dielectric properties, and AC conductivity of Bis(carbamoyl-guanidine amidinourea salt) diaquatetrachlorocuprate (II)
2023, Journal of Molecular StructureCitation Excerpt :The ammonium ion of organic group builds up hydrogen bonds with halide ions of inorganic layer, which makes these materials powerful candidates for proton conduction with a high potential for technological applications [11]. One of the best studied groups, both in solution and solid state, are the halogenocuprates complexes [12,13]. Their primary interest derives from the fact that they are able to assume, with great ease, very different geometries.
A new organic-inorganic hybrid compound (C<inf>10</inf>H<inf>28</inf>N<inf>4</inf>)[CuCl<inf>4</inf>][BF<inf>4</inf>]<inf>2</inf>: Structural, optical, thermal studies and DFT-TDDFT calculations
2022, Journal of Molecular StructureCitation Excerpt :The atomic arrangement of the compound shows that the copper (II) atom is surrounded by four chlorine anions, while the boron by four fluorine atoms. The bond distances around the copper (II) and boron atom reported in Table 2 are consistent with the literature [28,29]. The geometry of four-coordinated metal complex may conveniently be measured by the Yang τ4- parameter [30], τ4 = [360 - (β + α)]/141 with β and α being the two largest angles, that is zero for a perfect square planar geometry and one for a perfect tetrahedral geometry.
Low pH-induced lone-pair activity in the hybrid (C<inf>6</inf>H<inf>10</inf>N<inf>2</inf>)[SnCl<inf>3</inf>]Cl: Chemical study and physical characterizations
2022, Journal of Molecular StructureCitation Excerpt :The title compound can generate semi-conduction properties by referring to similar works [18,45]. Considering the interest in the photoluminescence phenomenon of hybrid metal halogenates [90], we further examined the luminescent properties of the title compound at room temperature. Fig. 15 shows the photoluminescence spectrum of (C6H10N2)[SnCl3]Cl determined in solid state at room temperature under excitation at 380 nm.
Crystal structure, DFT studies and thermal characterization of new luminescent stannate (IV) based inorganic-organic hybrid compound
2021, Journal of Molecular StructureCitation Excerpt :Referring to similar works [49,50], the title compound can generate semi-conduction properties. The structural diversity and dimensional variability in the anion structures are the main factors accounting for the photoluminescence phenomenon [51]. The combination of metal and organic centers in inorganic-organic compounds provides an excellent path to a new type of photoluminescent materials [52–54].