Relations between Structural and Luminescence Properties of Novel

Article pubs.acs.org/IC

Cite This: Inorg. Chem. XXXX, XXX, XXX−XXX

Relations between Structural and Luminescence Properties of Novel Lanthanide Nitrate Complexes with Bis-phosphoramidate Ligands Khodayar Gholivand,*,†,# Mahdieh Hosseini,†,# Yazdan Maghsoud,† Jan Valenta,‡ Ali Asghar Ebrahimi Valmuzi,† Agata Owczarzak,§ Maciej Kubicki,§ Morteza Jamshidi,∥ and Mohammad Kahnouji† †

Department of Chemistry, Faculty of Science, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran Department of Chemical Physics & Optics, Faculty of Mathematics & Physics, Charles University, Ke Karlovu 3, Prague 2CZ-12116, Czechia § Department of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań, Poland ∥ Young Researchers and Elite Club, Kermanshah Branch, Islamic Azad University, P.O. Box 6718997551, Kerman-shah 1477893855, Iran

Inorg. Chem. Downloaded from pubs.acs.org by UNIV AUTONOMA DE COAHUILA on 04/05/19. For personal use only.

‡

S Supporting Information *

ABSTRACT: Five new bisphosphoramide-based LnIII nitrate complexes [La 2 (NO 3 ) 6 L 3I ] n (1), [Ce 2 (NO 3 ) 6 L 3I ] n (2), [Sm 2 (NO 3 ) 6 L 3II ] n (3), I III Sm2(NO3)6LIII 3 (4), and Er(NO3)3L2 (5) [L = piperazine-1,4-diylbis(diphenyl phosphine oxide), LII = N,N′-(ethane-1,2-diyl)bis(N-methyl-P,P-diphenylphosphinic amide, and LIII = N,N′-(ethane-1,2-diyl)bis(P,P-diphenylphosphinic amide)] have been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), and single crystal X-ray and powder diffractions. The results of the X-ray diffraction analysis revealed the new polymorph of LIII, and the structural diversity of the synthesized complexes in the solid state. Complexes 1−3 display two-dimensional coordination polymers (2D-CP), containing layers with honeycomb (6, 3) topology. In these 2D-CPs, each Ln center (La, Ce, and Sm in 1, 2, and 3, respectively) could be considered as a triconnected node, linked by three bridging bisphosphoramide ligands as two-connecting linkers. In contrast, 4 is a discrete binuclear complex, in which bidentate LIII ligand has two entirely different conformations: the syn chelating and the anti bridging. Cationic complex 5 shows the monomeric structure, where bidentate LIII adopts the syn-chelating conformation. A comprehensive luminescence investigation has been performed on free ligands and their corresponding complexes as well. The synthesized compounds display a variety of luminescence behavior, including the ligand-centered fluorescence in 1, 2, and 5, two distinct emission peaks in 1 and 2, characteristic Sm-centered f−f emission in 3 and 4, and excitation-dependent emission in LIII, 1, and 2. Furthermore, the timedependent density functional theory (TD-DFT) study was carried out on the reported compounds to understand the nature of the emission peaks and the observed luminescence properties. The solid-state emission quantum yields of lanthanide complexes were also determined at different excitation wavelengths.

■

INTRODUCTION The lanthanide (Ln) complexes have engrossed a significant number of experimental and theoretical researchers’ investigation through recent decades, owing to their biological applications,1 photophysical properties,2 and their substantial significance in separation sciences.3 The intense luminescence emission by lanthanide complexes is commonly observed because of the long-lasting (milliseconds time scale) excited states of Ln3+ ions.4 Luminescence has been an efficient instrument since it was discovered,5 and these lanthanide elements have played essential roles in lighting, and light conversion apparatus such as lasers,6 cathode-ray,7 plasma displays,8 and light-emitting diodes.9 So, these applications begat some most exciting advancements in the coordination chemistry of lanthanide ions.4 © XXXX American Chemical Society

Lanthanide complexes have a wide range of photoluminescence properties.10 The energy transfer processes from an organic ligand to the metal center is as significant as ligand- and metal-centered luminescence.8 Ln3+ ions display weak fluorescence due to the spin- and parity-forbidden f−f transitions; therefore, it seems to be a key criterion to utilize the proper organic linker molecules, often called “light harvester” or “antenna” molecules, with high absorption of light and the ability to effectively transfer of the absorbed energy to the metal ions.11 It is well-acknowledged that lanthanide ions have affinity for hard donor atoms, ergo, ligands having oxygen atoms have Received: December 27, 2018

A

DOI: 10.1021/acs.inorgchem.8b03611 Inorg. Chem. XXXX, XXX, XXX−XXX

Article

Inorganic Chemistry been widely used in the synthesis of lanthanide complexes. In this regard, several classes of ligands such as cryptands,12 βdiketones,13 and carboxylic acids14 have been applied. Correspondingly, special attention has been paid to phosphoryl-containing ligands, i.e., phosphine oxides15 and phosphates,16 because of their established high potential interaction with lanthanide ions. Additionally, the lower vibrational frequencies of the PO bonds rather than CO ones leads to a lesser probability to nonradiative quenching of the lanthanide ions’ excited state.17 The synthesis and X-ray characterization of a high number of lanthanide complexes of phosphine oxides18 and multifunctional phosphine oxide based ligands19 have been published so far. It has been proven that from the energy point of view, phosphine oxide ligands have better potential interaction with lanthanides rather than phosphates, amides, and pyridine derivatives.20 Moreover, it is demonstrated that the bidentate structures of phosphine oxide ligands can be promising to form the rigid structure of the lanthanide complex and improve the resultant luminescence properties.21 However, our research group has shown before that the cation affinity of such phosphoramides is very close to that of phosphine oxides from the energy viewpoint and the phosphoramides generate stronger Ln−OP bonds (where OP is the phosphoryl oxygen atom).22 Due to the more accessible and cheaper synthetic method of phosphoramide compounds,23 as well as their higher thermal resistance than phosphine oxides,24 we have recently shown that they can be considered proficient ligands through lanthanide complexation.25 Taking the above into account and as an expansion of our work on lanthanide complexes with phosphoramidate ligands, we have employed three bisphosphoramidate ligands due to complexation and investigate the luminescence behavior of the ligands and corresponding complexes. Five novel lanthanide complexes, namely, [La2(NO3)6LI3]n (1), [Ce2(NO3)6LI3]n (2), III [Sm2(NO3)6LII3 ]n (3), Sm2(NO3)6LIII 3 (4), and Er(NO3)3L2 I II (5) [L = piperazine-1,4-diylbis(diphenylphosphine oxide), L = N,N′-(ethane-1,2-diyl)bis(N-methyl-P,P-diphenylphosphinic amide, and LIII= N,N′-(ethane-1,2-diyl)bis(P,P-diphenylphosphinic amide)] have been successfully synthesized (Scheme 1). The newly synthesized complexes have been elucidated by single-crystal X-ray diffraction, powder X-ray diffractometry (PXRD), infrared (IR) spectroscopy, thermogravimetric analysis (TGA), and elemental analyses. The crystal structures of a new polymorphic form of LIII as well as lanthanide complexes and their packing systems have been studied using geometrical parameters. Five lanthanide complexes show different solid state structures. Complexes, 1, 2, and 3 form two-dimensional coordination polymers (2D-CP), whereas 4 and 5 demonstrate binuclear and monomeric structures, respectively. To further understand the structure of 2D-CPs, the topological analysis was also carried out. Besides, the photophysical properties of the ligands and complexes have been investigated in detail by fluorescence spectroscopy. Time-dependent density functional theory (TDDFT) has been used to study the photoabsorption properties of synthesized ligands and complexes in the presence of timedependent potentials.

■

Scheme 1. Synthetic Route of 1−5

Experimental Details. Syntheses and Characterization of LI− LIII, 1−5. LI and LII. LI and LII ligands have been reported by our group elsewhere26 and were used as-synthesized for investigation of luminescence properties according to the literature. N,N′-(Ethane-1,2-diyl)bis(P,P diphenylphosphinic amide), LIII. The title compound was synthesized by the reaction of 2 mmol of (C6H5)2P(O)Cl and 1 mmol of ethylenediamine in the presence of Et3N as HCl scavenger in CH2Cl2 at room temperature. After stirring for 24 h, the solvent was evaporated, and the residue was washed with distilled water and dried. A white solid resulted in a yield of 70%. Colorless needle X-ray quality crystals of LIII were obtained by crystallization of as-synthesized materials of this ligand in chloroform/ n-hexane solvents mixture at room temperature. Physical and spectroscopic data of LIII are presented below. FT-IR (KBr pellet, cm−1): 3175.6 (N−H), 2927.9 (s), 1438.5 (s), 1176.5 (PO), 1111.7 (s), 722.2 (P−N). Mp 228−230 °C. 1H NMR (500.13 MHz, DMSO-d6, 25 °C, TMS) δ 2.88 (m, 4 H, CH2− CH2), 5.51 (m, 2 H, NH), 7.43−7.47 (m, 8 H, C6H5), 7.49−7.52 (m, 4 H, C6H5), 7.73−7.77 (m, 8 H, C6H5) ppm. 13C NMR (125.75 MHz, DMSO-d6, 25 °C, TMS) δ 42.02 (d, 2JPC = 6.1 Hz, 2 C, CH2− CH2), 128.35 (d, 3JPC = 12.1 Hz, 8 C, meta-C6H5), 131.37 (s, 4 C, para-C6H5), 131.57 (d, 2JPC = 9.4 Hz, 8 C, ortho-C6H5), 133.60 (d, 1 JPC = 126.5 Hz, 4 C, ipso-C6H5) ppm. 31P{1H} and 31P NMR (202.45 MHz, DMSO-d6, 25 °C, H3PO4 external) δ 21.88 (m) ppm. Anal. Calcd for LIII: (Mw = 460.45 g mol−1): C, 67.82%; H, 5.69%; N, 6.08%. Found: C, 67.69%; H, 5.77%; N, 5.93%. General Procedure for the Preparation of Complexes. The complexes were prepared by using the similar technique: Methanol− chloroform solutions of 1 equiv of Ln(NO3)3·6H2O (Ln: La, Ce, Sm, and Er) with 1 equiv of the bisphosphoramide ligand were mixed. Suitable crystals of LI·La (1), LI·Ce (2), LII·Sm (3), LIII·Sm (4), and LIII·Er (5) for X-ray analysis were obtained from the slow evaporation

EXPERIMENTAL SECTION

General. All chemicals and solvents used in the syntheses were commercially available and were used without further purification. B


Article

Inorganic Chemistry

1818559 (3), 1450513 (4), and 1450511 (5). Copies of this information may be obtained free of charge from The Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK. Fax: + 44(1223)336−033, e-mail: [email protected], or Web site: https://www.ccdc.cam.ac.uk/. Powder X-ray Diffraction and Refinement. X-ray powder diffraction (XRD) measurements were performed using an X’pert Pro MPD diffractometer with monochromated Cu Kα radiation (λ= 1.54056 Å). The simulated XRD powder pattern based on single crystal data was prepared using Mercury software. Elemental Analysis. Elemental analysis was performed using a Heraeus CHN−O RAPID apparatus. NMR and FTIR. 1H, 31P, and 13C NMR spectra were recorded on a Bruker Avance DRX500 MHz NMR spectrometer. TGA-DTA. Thermogravimetric analyses were performed on a Netzsh STA 449 F3 Jupiter Thermobalance. Typically, 2.5 mg of powder was heated from room temperature to 1000 °C at 10 °C min−1, under a nitrogen atmosphere. Photoluminescence Spectroscopy. Microphotoluminescence (PL) emission was excited with the 402 nm diode laser in epifluorescence configuration of an inverted microscope coupled to an imaging spectrometer with LN-cooled CCD camera. The objective lens with low magnification (4× ) was used. Photoluminescence (PL) emission and excitation spectra were measured in a small fluorescence spectrometer with excitation by a Xe lamp coupled to a monochromator and detection through a second monochromator with a photomultiplier. Photoluminescence external quantum yield was measured using the setup based on an integrating sphere (IS) (diameter of 10 cm) with excitation by a laser-driven light-source (LDLS) coupled to a monochromator. Selected excitation band is coupled via an optical fiber bundle to IS and output signal is detected (again via fiber coupling) by the 30 cm spectrometer and BI-DDCCD camera.30 Excitation density is very low (microwatts per cm2), the excitation band has about 10 nm fwhm. The setup is absolutely calibrated using the secondary standard of spectral irradiance (Oriel, model 63358). Computational Study. All the DFT calculations were carried out by the Gaussian 09 suite of programs.31 Recent studies indicated that the CAM-B3LYP density functional is a more reliable method for study charge-transfer complexes over the most popular methods, e.g., B3LYP.32 Hence, Coulomb-attenuating method (CAM-B3LYP) was used as a hybrid exchange-correlation functional, which combines the hybrid qualities of B3LYP and the long-range correction presented by Tawada et al.33 All the structures were cut out directly from the CIF data: the ECP46MWB,34 ECP47MWB,35 ECP51MWB,36 and ECP57MWB37 basis sets were used for La, Ce, Sm, and Er, respectively, along with the 6-31+G* basis set for other atoms. The spin state of all the optimized neutral structures was considered as a singlet. To obtain vertical electron excitation energies, time-dependent DFT (TD-DFT) calculations at the CAM-B3LYP/ECPX/631+G* levels were performed on the structures. The frontier molecular orbitals were drawn using the Gauss View 5.0.8 program.38

of the solution at room temperature. Physical and spectroscopic data of the complexes are given below: [La2(NO3)6LI3]n (1). The title compound was formed as colorless block crystals, and the formula was found from the X-ray diffraction experiment. Yield 50% based on La. IR (KBr, cm−1) 3419s (υN−H), 2925w (υaliph.), 2857w (υaliph.), 1632m, 1130s (υPO), 1076s, 965s (υP−N). Anal. Calcd for C84H84La2N12O24P6 (Mw = 2109.31 g mol−1): C, 47.83%; H, 4.01%; N, 7.97%. Found: C, 47.76%; H, 4.12%; N, 7.86%. [Ce2(NO3)6LI3]n (2). The title compound was formed as colorless prism crystals, and the formula was found from the X-ray diffraction experiment. Yield 38% based on Ce. IR (KBr, cm−1) 3402s (υN−H), 2922w (υaliph.), 2863w (υaliph.), 1624m, 1132s (υPO), 1073s, 968s (υP−N). Anal. Calcd for C84H84Ce2N12O24P6 (Mw = 2110.23 g mol−1): C, 47.78%; H, 4.01%; N, 7.96%. Found: C, 47.70%; H, 4.13%; N, 7.89%. [Sm2(NO3)6LII3]n (3). The title compound was formed as colorless block crystals, and the formula was found from the X-ray diffraction experiment. Yield 42% based on Sm. IR (KBr, cm−1) 3419s (υN−H), 2925w (υaliph.), 2857w (υaliph.), 1632m, 1130s (υPO), 1076s, 965s (υP−N). Anal. Calcd for C84H90Sm2N12O24P6 (Mw = 2138.27 g mol−1): C, 47.18%; H, 4.24%; N, 7.86%. Found: C, 47.26%; H, 4.30%; N, 7.91%. Sm2(NO3)6LIII 3 (4). The title compound was formed as colorless prism crystals, and the formula was found from the X-ray diffraction experiment. Yield: 6.4 mg, 48% based on Sm. IR (KBr, cm−1) 3323 (υN−H), 3062w (υaliph.), 2947w (υaliph.), 1466s, 1150s (υPO), 1105s, 732s (υP−N). Anal. Calcd C78H78N12O24P6Sm2 (Mw = 2054.10 g mol−1): C, 45.61%; H, 3.83%; N, 8.18%. Found: C, 45.63%; H, 3.91%; N, 8.15%. Er(NO3)3LIII 2 (5). The title compound was formed as colorless prism crystals, and the formula was found from the X-ray diffraction experiment. Yield 52% based on Er. IR (KBr, cm−1) 3220s (υN−H), 2061w (υaliph.), 2927w (υaliph.), 1482s, 1374m, 1155s (υPO), 1028s, 945s (υP−N). Anal. Calcd for C52H52ErN7O13P4 (Mw = 1274.18 g mol−1): C, 49.02%; H, 4.11%; N, 7.70%. Found: C, 49.13%; H, 4.06%; N, 7.78%. Single Crystal X-ray Crystallography. X-ray intensity data were collected at 100 K on a Bruker SMART APEXII CCD diffractometer (LIII and 2), on an APEX II DUO diffractometer (3), and on Agilent Technologies XCalibur at room temperature (1, 4) and at 120(1) K (5) with graphite-monochromatized Mo Kα radiation (λ = 0.71073 Å). The structures were solved by direct methods and refined with the full-matrix least-squares procedure on F2 by SHELXL-2013.27 The scattering factors incorporated in SHELXL9728 were used. All nonhydrogen atoms were refined anisotropically, hydrogen atoms in structure LIII were found in the difference Fourier maps and freely isotropically refined. In all other structures, these atoms were placed in idealized positions and refined as “riding model” with isotropic displacement parameters set at 1.2 (1.5 for methyl groups) times Ueq’s of appropriate carrier atoms. In 1 and 2, the voids filled with diffused electron density were found; as the modeling of solvent molecules was in these cases unsuccessful, the SQUEEZE29 procedure was applied. In four complex structures, disorder has been observed. As a consequence, constraints for geometry and/or displacement parameters were applied. In the structure of 1, one of the ligands is disordered; the s.o.f.’s for disordered parts refined at 62.7(12)/37.3(12)% for the benzene and 51.0(17)/49.0(17)% for the piperazine rings. In the case of 2, the same groups are disordered, and s.o.f.’s converged at 59.1(11)/ 40.8(11)% (phenyl) and 59.7(18)/40.3(18)% for (piperazine). In 3, two atoms C41 and C42 (methyl/CH2) were disordered; in this case, s.o.f. refined at 41.1(12)/38.9(12)%. In 4, again one of the phenyl rings is disordered with s.o.f.’s of 62(3)/38(3)%. Finally, in the structure of 5, the ligands and also the free nitrate ion are disordered. The s.o.f.’s for disordered parts refined at 52.1 (13)/47.9(13)% for benzene ring and 50/50 (due to the symmetry) for nitrate anion. Crystallographic data (excluding structure factors) for the structural analysis has been deposited with the Cambridge Crystallographic Data Centre, CCDC Nos. 1818556 (LIII), 1450035 (1), 1818558 (2),

■

RESULTS AND DISCUSSION Syntheses of the Complexes. Ligands LI, LII, and LIII, were prepared by mixing the diphenyl phosphinic chloride and the corresponding amine solutions. The reaction of equimolar amounts of these ligands and LnIII(NO3)3 (Ln = La, Ce, Sm, and Er) in methanol/ chloroform solvent mixture gave the related complexes. Slow evaporation of the solvents caused air-stable block crystals of 1 and 3 and prism crystals of 2, 4, and 5 after a few days. The single crystal samples were analyzed by single-crystal X-ray diffraction. Crystallographic parameters and structural refinement details for compounds are listed in Table S1. Description of Crystal Structures. Structural Analysis of LI, 1, and 2. The crystal structure of LI has been reported by us elsewhere,26a but for exploring the changes from ligand to C


Article

Inorganic Chemistry complexes 1 and 2, comparing some parameters seems worthy of mention. Hereupon, the defined dihedral angles (Figure S1) and distances of LI are summarized in Table S2. In the crystal structure of LI, two phosphoryl groups take the anti conformation. The PO distance in LI is equal to 1.489(3) and is in a normal range. Single crystal X-ray crystallography shows that complexes 1 and 2 are two-dimensional coordination polymers which crystallize in a triclinic system, P1̅. LI coordinates to La and Ce atoms in a bidentate mode, and the PO donors are in the anti fashion. Anisotropic ellipsoid representation of 1 and the atom labeling schemes are shown in Figure 1a. In neutral complex 1, the central La ion is

Figure 2. (a) Representation of metallacyclic rings in 1, showing the three different conformations for the LI linkers and the resulting three different La···La distances (hexagonal window edges). (b) 2D layer structure of compound 1. (c) and (d) Topology view of the honeycomb layers with (6, 3) net in 1; different colors show different conformations of LI. Figure 1. (a) Perspective view of a fragment of the polymeric structure 1, showing the full environment of the La ion. Ellipsoids are drawn at the 30% possibility level, hydrogen and disordered atoms are omitted for visual clarity. Symmetry codes: i: 1 − x, 2 − y, −z; ii: 1 − x, 2 − y, 1 − z; iii: 1 − x, 1 − y, 1 − z; (b) Coordination geometry of the La atom in compound 1.

sheets are composed of La(NO3)3 units and μ-LI linker ligands. The μ-LI ligands show three different conformations in the crystal structure of 1; the geometries of three conformers of LI in 1 are summarized in Table S2. As it is shown in Figure 2a, different conformations of LI cause three different La···La separations (10.00, 10.12, and 10.49 Å). These three conformers are shown with different colors in Figure 2. The 2D sheets are further stabilized via intrachain CH···π contacts: C5D−H5D···π along c-direction and C14D− H14A···π and C4F−H4F···π along the a-axis. Each La atom can be considered a three-connected node, topologically. The joining of La atoms by LI linkers forms a two-dimensional sheet structure with a 63-hcb net (Figure 2c,d). Adjacent 2D layers are further interconnected by interlayer contacts. Hydrogen bonds between phenyl ring of one layer and coordinated nitrate oxygen atoms of another one and also CH···π interactions between neighboring layers’ phenyl rings result in a 3D supramolecular architecture (Figure S2). A summary of the parameters for the interactions mentioned above is presented in Tables S5 and S6.

9-coordinated in a muffin geometry (MFF) shape, established by continuous shape analysis39 (Table S4), enclosing six oxygen atoms from three nitro groups (O1A, O2A, O1B, O2B, O1C, and O2C) and three oxygen atoms from the ligand molecules, O1D, O1E, and O1F (Figure 1b). Table S3 lists the relevant geometric parameters of 1. The asymmetric part of the structure comprises one metal ion, three nitro groups and three halves of the ligand molecules. La−O phosphoryl bond lengths are shorter than La−O nitrate ones. La−O bond distances are in the range of 2.415(3)−2.651(7) Å and the O−La−O bond angles fall in the range of 46.76(16)−157.84(12)°. Piperazine rings of ligand molecules lie on the centers of symmetry and connect two different metal ions. This coordination pattern causes the formation of endless polymeric chains, extended along the c and b axes, producing a twodimensional coordination network (Figure 2). Thus, the 2D D


Article

Inorganic Chemistry After evaluating the crystal structure of 2, it was observed that this complex is isostructural with 1. This aspect was investigated through XPac method.40 This program compares the crystal structures of different compounds by defining a numerical descriptor, dissimilarity index (X), between them. More comparable structures have a smaller magnitude of X. The XPac results suggested that there is a 3-dimensional similarity between 1 and 2 as can be seen from the overlay and packing diagrams in the Supporting Information. The data from the XPac analysis are listed in Table S7. Moreover, the relevant plots from XPac analysis, gained from the program are given in Figure S3. The dissimilarity index (X) for 1 and 2 was found to be 4.1, so these coordination polymers are isostructural. Hence, only the structure of 1 has been discussed here as an illustrative example. The anisotropic ellipsoid representation, Ce coordination polyhedra, metallacyclic rings, crystal structure descriptions, and topological views of 2 are given in Figures S4−S7. Table S3 lists the geometric parameters around Ce atom. Also, the geometries of three conformers of LI in 2 are summarized in Table S2. The significant difference in the crystal packing of these two complexes, is the presence of π···π interaction, connecting 2D polymeric sheets in 2 (Figure S7c). Structural Analysis of LII and 3. The crystal structure of LII has been reported by us before,26b but we can investigate the alternations from ligand to complex 3 by comparing some parameters. In the crystal structure of the ligand LII, two phosphoryl groups take anticonformation. The PO distance in LII is 1.4965(9). The geometries of this ligand are given in Table S2. Single crystal X-ray crystallography shows that 3 is a 2D-CP, which crystallizes in a monoclinic system, P21/c. LII coordinates to Sm atom in a bidentate mode and the PO donors are in an antifashion. Anisotropic ellipsoid representations of 3 and the atom labeling schemes are shown in Figure 3a. In neutral complex 3, the central Sm ion is 9-coordinated, with a muffin (MFF-9) shape coordination polyhedra (Table S4), made up of six oxygen atoms from three nitro groups (O4, O5, O7, O8, O10, and O11) and three oxygen atoms from the ligand molecules, O1, O2 and O3 (Figure 3b). The asymmetric unit of 3 contains one metal ion, three nitro groups, and one and a half of ligand molecule. Sm−O bond distances are in the range of 2.314(2)−2.556(3) Å, where the Sm−O phosphoryl bond lengths are shorter than the Sm−O nitrate ones. The O−Sm−O bond angles fall in the range of 50.35(9)−154.32 (9)°. Table S3 lists the relevant geometric parameters. In this structure, bidentate LII ligands act as a bridge between metal centers. By the coordination of LII linkers to the Sm centers with the assistance of CH···π contacts along a-axis (Figure 4a), as well as other CH···π contacts and π···π interactions along b-axis, the 54-membered [Sm6(μ-LII)6] metallacyclic rings are formed (Figure 4b). Linking of these [Sm6(μ-LII)6] units makes 2D sheets in ab-plane with the 63hcb network (Figure 4c,d). Two different conformations of μLII are involved in the formation of the 2D-honeycomb structure of 3. The geometries of two conformers in 3 are summarized in Table S2. The two conformations of LII in complex 3 are shown in different colors in Figure 4, making two different Sm···Sm separations (10.80 and 10.55 Å). Along the c-axis, the molecules of each sheet join together by hydrogen bonding between the oxygen atoms of nitrates and hydrogen atoms of phenyl rings and also CH···π contact, which

Figure 3. (a) Perspective view of a fragment of the polymeric structure 3, showing the full environment of the Sm ion. Ellipsoids are drawn at the 30% probability level; hydrogen and disordered atoms are omitted for visual clarity. Symmetry codes: i: −x, 1/2 + y, 1/2 − z; ii: 1 − x, 1 − y, 1 − z. (b) Coordination geometry of the Sm atom in compound 3.

pack these 2D sheets in an ABAB fashion (Figure S8). A summary of the parameters for the interactions, involved in the crystal packing of 3, is presented in Tables S5 and S6. Structural Analysis of LIII, 4, and 5. LIII can possess anti and syn conformations by the relative directions of the PO groups, which permits the conformational adoption of this ligand in different Ln(III) complexes. To have a better understanding of the structural alterations of LIII from free ligand to complexes 4 and 5, we determined its structure by Xray diffraction study. It should be noted that a different crystal form (polymorph) of LIII was reported quite recently.41 However, herein we will discuss solid state structure of our synthesized polymorphic form of LIII. In that reported structure, the polymorph of LIII crystallizes in triclinic P1̅ space group with four halves of Ci-symmetrical molecules in the asymmetric part of the unit cell. Nonetheless, our single crystal studies revealed that LIII display P21/n space group with Z = 4 and two halves of Ci-symmetrical molecules, making up the asymmetric unit. Anisotropic ellipsoid view and labeling scheme of this compound are shown in Figure 5a. The PO distances of 1.490 (2) and 1.491 (2) for two molecules in the asymmetric unit of LIII are in the normal ranges. As displayed in Figure 5a, and as a consequence of symmetry of the molecules, LIII adopts an anticonformation in both polymorphic forms in the solid state; the geometries of two conformers of LIII are summarized in Table S2. E


Article

Inorganic Chemistry

Figure 5. (a) Anisotropic ellipsoid representation of LIII. Ellipsoids are drawn at the 30% probability level. Symmetry codes: i: 2 − x, −y, 2 − z; ii: 1 − x, 1 − y, 2 − z. (b) Side view of the crystal packing in the ab-plane, which shows how the chains are connected in the crystal structure; (c) side view of the crystal packing of LIII in the bc-plane. (d) Intermolecular interactions linking the neighboring molecules in the bc-plane, which shows how the chains are connected to the 3D construction; different colors indicate different conformations of LIII.

Figure 4. Crystal packing of 3: (a) CH···π interaction within a chain; (b) 2D layer structure of 3. (c) and (d) Topology view of the honeycomb layers with (6, 3) net in 3; different colors show different conformations of LII.

X-ray analysis showed that 4 crystallizes in the monoclinic system P21/n with Z = 2. Anisotropic ellipsoid representation and labeling scheme of 4 are shown in Figure 6a. As shown in Figure 6b, in the crystal structure of 4, LIII adopts two various conformations, depicted with two different colors, and consequently, two different coordination modes; chelatingbidentate coordination mode as well as bridging bidentate coordination fashion. The geometries of two conformers in 4 are summarized in Table S2. The asymmetric unit of 4 contains one crystallographic independent Sm ion, one bidentate LIII ligand with syn conformation, a half bidentate L III ligand with anti conformation, and three coordinated nitrate ions. Two equivalent units of [Sm(NO3)3LIII] are located in the inversion centers, joined by one anti LIII ligand. The Sm centers in 4 have nona-coordinate geometry, which is best described as a

The nonclassical hydrogen bonds, which are those between phenyl’s C−H donor and oxygen acceptors from PO, associate molecules together and form a 1D chain along the aaxis (Figure 5b). These 1D chains are further linked to generate 2D sheets by CH···π interactions in the ab-plane (Figure 5b). The adjacent 2D sheets are connected to each other by classical N−H···O hydrogen bonds, nonclassical C− H···O hydrogen bonds between C−H phenyl donor and oxygen acceptors form PO and weak intermolecular CH···π contacts. All of these interactions result in the overall 3D supramolecular architecture (Figure 5c,d). Summaries of the parameters for these interactions are presented in Tables S5 and S6. F


Article

Inorganic Chemistry

Figure 6. (a) Anisotropic ellipsoid representation of 4. Ellipsoids are drawn at the 30% probability level. Hydrogen atoms are omitted for visual clarity. Symmetry codes: i: 1 − x, − y, 1 − z; (b) different conformations and coordination modes of LIII ligand in 4. (c) Coordination geometry of the Sm atom in compound 4; different colors specify different conformations of LIII.

muffin MFF (Cs) by Shape analysis (Table S4). The coordination polyhedra is formed by two oxygen atoms from the chelating LIII ligand (O1A, O2A), one oxygen atom from the bridging LIII ligand (O1B), and six oxygen from three coordinated nitrate ions (O1C, O2C, O1D, O2D, O1E, and O2E, Figure 6c). Thus, two LIII chelator ligands, one bridging LIII ligand, six nitrates, and two Sm ions arrange the binuclear discrete units in the crystal structure of 4. The Sm···Sm distance in the binuclear unit is 11.442 Å. Sm−O bond distances are in the range of 2.312(2)−2.558(4) Å, the Ln−O phosphoryl bond lengths are shorter than the Sm−O nitrate ones. The O−Sm−O bond angles fall in the range of 48.22(13)−163.94(9) (Table S3). The binuclear units joined together by three CH···π contacts to form molecular chains along the a-direction (Figure 7a). These chains are laterally linked via various intermolecular interactions to generate a 3D supramolecular architecture (Figure 7b). Along the b-direction, molecules are held together by another CH···π interactions (Figure 7c). The molecular chains are firmly attached by a three-dimensional (3D)

Figure 7. Crystal structure of 4; (a) CH···π interaction within a chain; (b) three-dimensional supramolecular structure of compound 4. (c) and (d) Intermolecular interactions linking the adjacent 2D layers in the bc-plane; noninteracting hydrogen atoms in (c) and (d) have been omitted for visual clarity. Different colors present different molecular chains.

supramolecular network through C−H···O and NH···O hydrogen bonds (Figure 7d). A summary of the parameters for the interactions mentioned above is presented in Tables S5 and S6. Cationic complex 5 crystallizes in the trigonal crystal system P3221 space group with Z = 3. X-ray analysis revealed that the asymmetric unit of 5 consists of one-half of Er(III) metal center, one bidentate bis-phosphoramide ligand LIII, one coordinated nitrate anion, and one-half of free nitrate counterion (NO3−). Anisotropic ellipsoid representation and labeling scheme of this compound are shown in Figure 8a. G


Article

Inorganic Chemistry

Figure 8. (a) Anisotropic ellipsoid representation of 5. Ellipsoids are drawn at the 30% probability level. Hydrogen and disordered atoms are omitted for visual clarity. Symmetry codes: i: 2 − x, 1 − x + y, 2/3 − z. (b) Conformation and the coordination mode of LIII ligand in 5. (c) Coordination geometry of the Er atom in compound 5.

The coordination geometry is made up of a discrete cationic III ErLIII 2 (NO3)2 unit. The Er O8 coordination geometry is best described as a Snub disphenoid JSD-8 (D2d) by shape analysis (Table S4), which is completed by four phosphoryl’s oxygen atoms (O1A, O2A, O1Ai, and O2Aii), and four oxygen atoms from two coordinated nitrate ions (O1B, O2B, O1Bi and O2Bi) (Figure 8c). In 5, PO donors are approximately in a syn fashion, unlike the free form of LIII, in which two PO groups take anti conformation. Thus, the nine-membered chelate rings are formed by one erbium, two oxygen, two phosphorus, two nitrogen, and two carbon atoms (Figure 8b). Er−O bond distances are in the range of 2.222(7)−2.463(6) Å, where Er−O phosphoryl bond lengths are shorter than the Er−O nitrate bond lengths. The O−Er−O bond angles fall in the range of 51.98(19)−156.3(2)°. Table S3 lists the relevant geometric parameters. Monomer subunits of 5 are connected to give an infinite chain by two CH···π interactions along the b-axis (Figure 9a). The strings are associated together by the nonclassic hydrogen bonds between two hydrogen atoms of the phenyl ring of one chain and two oxygen atoms of the coordinated nitrate ion of another. Besides, the hydrogen bonding between the strings and the in-between free nitrate anions form a 2D network (Figure 9b). Furthermore, adjacent 2D sheets are linked together by CH···π contacts results in the 3D framework (Figure 9c,d). A summary of the parameters for the interactions mentioned above is presented in Tables S5 and S6.

Figure 9. Crystal structure of 5. (a) Association of molecules in the chain along b-axis and adjoining of chains in ab-plane through CH···π interactions; (b) the intermolecular interactions present in the expanded part of (a) linking the neighboring molecules in the abplane. (c) Side view of the crystal packing of 5 in the ac-plane. (d) Intermolecular interactions connecting the adjacent 2D layers in the bc-plane. Noninteracting hydrogen atoms have been omitted for visual clarity. Violet and blue in (a) and (b) represent different molecular chains. Blue and red in (c) and (d) represent different 2D sheets.

Analysis of Lanthanide Contraction Effect. Five lanthanide nitrate complexes based on bis-phosphoramidate ligands were synthesized and characterized in this work. The study of the structural data is obtainable for direct experimental assessment of lanthanide contraction, which is well-known as more significant than expected decrease in ionic radii of the elements in the lanthanide series.42 Distances between Ln centers with oxygen atoms of ligands and nitrate ions in 1−5 are listed in Table S3. Ln−O bonds have been divided into Ln−O(L) (ligand) and Ln−O(N) (nitrate anion). Figure 10 shows the variation of ∑dLn−O(L)/m and ∑dLn−O(N)/ m for 1−5 with n, when m is the number of Ln−O distances, and n is the number of 4f electrons for each complex. In all H


Article

Inorganic Chemistry

Figure 10. Diagram of ∑dLn−O/m versus n for lanthanide ions 1−5, corresponding to the O atoms of the ligands (red squares) and the coordinated nitrate ions (blue triangles). m is the number of Ln−O bond for each complex, and n is the number of 4f electrons.

complexes, ∑dLn−O(L)/m is shorter than ∑dLn−O(N)/m. As evident in Figure 10, the Ln−O bond lengths decrease with the increasing of atomic numbers from 1 to 5. It is fascinating to note that even though 4 and 5 were built from the same ligand (LIII) and Ln(NO3)3·6H2O under similar reaction conditions, they exhibited two completely different 3D constructions with a variation of LIII coordination modes, which is mainly attributed to lanthanide contraction.43 Ongoing from Sm (4) to Er (5), the coordination numbers of Ln ions decrease from 9 to 8 as the ionic radii of the Ln ions decreases. Photoluminescence Spectroscopy. Solid-state luminescence spectra of 1−5 and free LI, LII, and LIII ligands, recorded at room temperature, are shown in Figures 11−14, and the corresponding excitation spectra are illustrated in Figure S9. The emission spectrum of LI is composed of a peak at 434 nm with a shoulder at 470 nm that could be attributed to the n → π* and π → π* transitions of the aromatic rings and also PO and P−N groups (Figure 11). LII reveals an emission band in the range of 430−700 nm (λmax = 470 nm), which can be assigned to the π → π* transitions of the aromatic rings. Upon excitation at 350 nm, LIII shows an emission band with λmax = 450 nm. The emission band of this compound shifts to 460 nm by a change in the excitation wavelength to 370 nm. The shift of emission band can be attributed to the presence of the second molecule in the solid state of this ligand (Figure 11). In the solid state, under excitation at 370 nm, the emission band of LI·La (1) and LI·Ce (2) are ligand-centered (Figure 12). The fluorescence emission peak (the main peak and its shoulder) in these complexes show a blueshift in comparison with the free ligand (emission peaks appeared at 417 and 436 nm in 1 and 420 and 437 nm in 2). Coordination of the ligand to the lanthanide center and as a result, the ligand-to-metal charge transfer (LMCT), can explain the reason for the blueshift in these complexes.44 Besides, two interesting phenomena occur in the solid-state emission of 1 and 2. First, a new peak, which did not appear in the PL of free ligand has emerged in the spectra of both complexes at a longer wavelength than the first peak, and second, changing the excitation wavelength shifts the emission bands of these two compounds (Figure 12). The fluorescence spectra of LI, 1, and 2 were measured in CH2Cl2 at room temperature to clarify the nature of the new lower energy peak (LE) in the emission spectrum of 1 and 2 and to monitor the probability of excitation dependency of

Figure 11. Emission spectra of LI, LII, and LIII in the solid state at RT.

emission bands in the solution (Figure S10). In the solution phase, LI shows the same emission peak as in the solid state, but in the PL spectra of 1 and 2, the higher energy (HE) emission peak is just observed, while the LE peak is missing. Likewise, in the solution, the emission spectra of 1 and 2 have not been shifted by varying the excitation wavelength. As it mentioned earlier in the “Description of Crystal Structures” section, there are three conformers of LI, attached to the La and Ce metal centers in the solid state of 1 and 2; subsequently, there are different energy levels of ligands, which permits energy transfer between different conformers in of these complexes. However, in the solution phase, molecules can rotate without restrictions to take the optimized conformations. Therefore, we can say that in the solid state the higher energy peak initiates from π → π* and n → π* intraligand charge transfer, and the LE emission originates from ligand-to-ligand charge transfer (LLCT). This point will be discussed in more details in the “TD-DFT Calculations” section. Moreover, Figure 12 illustrates the shift of the fluorescence emission-band spectra toward the shorter wavelengths with decreasing the excitation wavelength to 310 nm (the red lines). Also, the presence of two peaks is more conspicuous, which means that HE and LE emission peaks are more split when 1 and 2 are excited with 310 nm wavelength of radiation. As the excitation dependency has not been observed in the solution, this behavior presumably could be attributed to the different I


Article

Inorganic Chemistry

Figure 13. Emission spectra of LII·Sm(3) and LIII·Sm (4) in the solid state at RT (λex = 402 nm); the inset in the upper-left show the color photograph for the emissions of 3 and 4 under a UV lamp).

these two complexes (the inset in Figure 13). The presence of a ligand-centered peak in the fluorescence spectra of 3 and 4, indicates that the absorbed energy by the ligand has not been entirely transferred to the lanthanide ion, but looking at the emission spectra, it is evident that the intensity of 4G5/2 → 6 G9/2 transition is much stronger than the ligand emission. Thus, we can consider LII and LIII as an antenna which harvests the energy and increases the Sm ion emission intensity. The emission intensity of coordination polymer 3 is stronger than that of binuclear complex 4. This fact indicates that the emission spectra of these two complexes are susceptible to the different coordination environments of the Sm ion, which arises from dissimilarities in the structural motifs,45 just as shown in the single crystal structure analysis. Since the low-temperature phosphorescence instrument was not accessible, we were not able to determine the energy transfer processes of the synthesized complexes, but based on the PL emission spectra of 3 and 4, it can be said that the triplet energy of LII lies in a more proper energetic level to the resonant level of Sm3+ (4G5/2) in comparison with LIII. Furthermore, the Lack of N−H group with the quenching effect in 3 could be influential in its stronger emission.46 Under excitation at 370 nm, LIII·Er (5) only reveals the ligand-centered emission band (Figure 14). 5 shows a blue-

Figure 12. Emission spectra of LI·La (1) (up) and LI·Ce (2) (bottom) in the solid state at RT. The insets are drawn to display HE (higher energy) and LE (lower energy) emission peaks more clearly.

excited levels of the ligand’s various conformations, coordinated to La and Ce centers. Subsequently, distinct emission peaks would be detected. As long as each conformer has different energy levels, the emission wavelengths of ligandcentered transition and the LLCT peak would be shifted when the excitation energy is changed. The fluorescence spectra of LII·Sm (3) and LIII·Sm (4) have been recorded under excitation at 402 nm (Figure 13). The emission spectra of 3 and 4 demonstrate 4f−4f transitions alongside a broad band centered at about 350 nm. The emission spectra of 3 and 4 illustrate that the bisphosphoramidate ligand absorbs a part of the excitation energy and then transfers the energy to the Sm ion. Consequently, the metal center emits light as its characteristic wavelength. The ligand-centered emissions in the complexes show a little blueshift compared to those of the free ligands, which are probably due to the ligand-to-metal charge transfer (LMCT). 3 and 4 display five specific bands for the Sm(III) ion in the range of 550−850 nm. These emission bands are attributed to 4 G5/2 → 6H5/2 (563 nm), 4G5/2 → 6H7/2 (600 nm), 4G5/2 → 6 H9/2 (643 nm), 4G5/2 → 6H11/2 (703 nm), and 4G5/2 → 6H13/2 (785 nm) transitions. The spectrum is dominated by the 4G5/2 → 6H9/2 transition, which gives the light red color emission to

Figure 14. Emission spectra of LIII·Er (5) in the solid state at RT. J


Article

Inorganic Chemistry

spectroscopy may be related to these transfers, which did not exist before the formation of the complexes. After complexation, the metal ions (La3+ and Ce3+) may facilitate the procedure of ligand-to-ligand charge transfer (LLCT), which can interpret the new emission peaks. LI·La (1) demonstrates four Rydberg transfers at 290.8, 280.3, 279.4, and 220.6 nm. Similar transfers are observed for LI·Ce (2) at 301.9, 293.8, 289.9, 227.1, and 222.9 nm, respectively (Figure 16).

green emission band with maximum wavelength at 474 nm, indicating a redshift of 14 nm in comparison with the free ligand. The redshift is probably due to the change of conjugation and rigidity of LIII ligand after the coordination of Er3+ ion and the presence of free nitrate ion in the solid state.47 The emission quantum yield (EQY) was measured for lanthanide complexes at different excitation wavelengths; the results are summarized and plotted in Table S8 and Figure 15,

Figure 15. EQY determination results for 1−5, measured at different excitation wavelengths. Figure 16. Electron−hole orbitals in Rydberg transfers; (a) LI·La (1), (b) LI·Ce (2).

respectively. The maximum values of EQY for 1−5 upon excitation with different wavelengths are found to be 0.89, 0.32, 2.53, 2.20, and 1.38%, respectively. Except 4, which reveals an EQY peak in 440 nm excitation wavelength, the maximum EQYs of other samples are in the near UV band (380−390 nm), and the values of EQY decrease toward longer excitation wavelengths. TD-DFT Calculations. TD-DFT is an applicable tool to inspect the properties and dynamics of systems in the existence of time-dependent potentials, such as electric or magnetic fields.48 The effect of such fields on ligands and resultant complexes can be studied with this method to extract aspects like excitation energies and photoabsorption spectra.49 Herein, we have utilized TD-DFT to explain the cause of LE emission band presence in 1 and 2, the shift of emission band with changing the excitation wavelength in LIII, and assign the emission bands in 4, emission band redshift in 5, and emission band blueshift in 1, 2, and 4, compared with corresponding free ligands. Ligand LI in the first 15 excitation states shows local excitement and photoinduced electron transfers (PETs) in different wavelengths. Some PETs are illustrated in Figure S11, and calculated values are given detailed in Table S9. Given PETs are related to nitrogen and phosphorus electron lone pairs in the ligand structure. In excitation state, fully occupied orbitals are holes (in blue), while empty orbitals are electrons (in red). Apparently, after the excitation, related orbitals to electron donor atoms, change as a hole, whereas those related to acceptor atoms act like electrons. Complexes of La and Ce with ligand LI display the same behavior in excitation states. On the basis of the electron−hole theory, in addition to local excitement transfers, these complexes reveal Rydberg transfers in a new number of wavelengths (calculated values are given detailed in Tables S10 and S11). Emerged emission peaks in the fluorescence

In addition to Rydberg transfers, each of these complexes represents PETs at different wavelength many times. The most extended PETs in terms of distance are observable for both complexes (Figure S12). The existence of this phenomenon in those structures, in which the transfer is from chelator to fluorophore, causes blueshift in the fluorescence emission spectrum. Thus, the comparison of results between the ligand and the complex efficiently determines the reason for the fluorescence emission spectrum blueshift. It should be mentioned that the f quantum yield in these transfers severely affects the emission spectrum. Ligand LIII in the excited state has some local excitements and PET transfers (calculated values are given detailed in Table S12). The most considerable excitation of related PETs at 225.5 nm is shown in Figure 17a. After dimerization, this ligand shows a strong Rydberg transfer at 222.5 nm (Figure 17b and Table S13). Related PET transfers are weak and change to pseudo-Rydberg and local transfers. Thus, one can conclude that the monomer and dimer have different energy transfers. This fact can rationalize the shift of the emission peak by changing the excitation wavelength in the solid state fluorescence of this compound (Figure 17). LIII·Sm (4) has a PET-type charge transfer, which is from chelator to fluorophore. This transfer causes a little blue shift in the ligand-centered emission of the complex rather than the ligand (Figure S13 and Table S14). Furthermore, Rydberg transfers emerged in this complex, in which the n = 13 transfer causes f−f transfers and makes five emission peaks in the fluorescence emission spectrum. In this state, electron−hole excitation is situated on Sm atom (Figure S14). After coordination of LIII to the Er center, the ligandcentered fluorescence of 5, displays a redshift. In LIII·Er (5), all K


Article

Inorganic Chemistry

framework. The thermogravimetric analyses of 1−5 are shown in Figure S15. The TGA curves designate the thermal stability up to 272, 281, 303, and 247 °C for 1−4, respectively, and then a gradual decomposition of the framework. The TGA curve of 5 indicates the weight loss of 4.97% in the range 135− 195 °C, which is referred to the release of one equivalent of noncoordinating nitrate ion (calcd 4.86%). Then, the framework is stable up to 232 °C, and after that, the structure decomposes gradually. The crystalline products of LIII and 1−5 have been characterized by X-ray powder diffraction (PXRD) at room temperature (Figure S16). The observed XRD patterns are in good accordance with the simulated ones from the single crystal data which represent that the major phase of the powder samples relates to the crystalline phases.

■

CONCLUSIONS In conclusion, we have presented here five new lanthanide nitrate complexes based on three bisphosphoramidate ligands. The solid-state structure of complexes and also a new polymorph of LIII have been discussed. Complexes 1−3, which are built with LI and LII ligands, display similar (6,3)connected 2D-CP frameworks with nine-coordinated Ln(III) ions. 4 and 5 are synthesized with LIII ligand, which has two different coordination modes in these two complexes. LIII adopts the chelating coordination pattern in the cationic and monomeric structure of 5, whereas each discrete binuclear building block of 4 is comprised of two chelating and one bridging LIII ligand. Sm and Er ions are 9- and 8-coordinated in 4 and 5, respectively, which demonstrates the lanthanide contraction effect. Compounds 1−3 with a 2D network show higher thermal stabilities than discrete complexes of 4 and 5. The luminescence properties investigation of free ligands and their corresponding complexes revealed that LII and LIII ligands sensitize the characteristic luminescence of the Sm3+ ion in 3 and 4, respectively, which leads to emission in the visible region. The emission intensity of 2D-CP of 3 is stronger than that of binuclear complex 4, representing the stronger antenna effect of LII to Sm center in comparison to LIII. Furthermore, 1, 2, and 5 exhibit ligand-centered blue-green emission in the solid state. Emission bands of 1 and 2 are composed of two distinct peaks. On the basis of the crystal structure description of 1 and 2 and the TD-DFT results, it seems that both emissions are initially from ligand-centered transitions, which the second emission is strictly relevant to the interligand charge transfer (LLCT) in the solid state. Moreover, the excitation dependency of LIII, 1, and 2 emissions are attributed to the presence of two different conformations of LIII in the crystal structure of this compound and likewise the distinct conformation of LI in the solid state of 1 and 2. This work gives insight into photoluminescence mechanism and surveys the connection between the structure of lanthanide complexes and their luminescent properties. From a more overall viewpoint, the phosphoramidate-based Sm(III) complexes may have the potential application as fluorescent markers in biology and medicine.

Figure 17. Illustration of electron−hole orbitals in ligand LIII: (a) monomer, (b) dimer.

15 excitation states are PET type, but referring to the crystalline structure of this complex and calculated results of TD-DFT (calculated values are given detailed in Table S15), it is evident that the uncoordinated NO3− group acts as the hole and in all absorption wavelengths of this complex demonstrate the PET process (Figure 18). This fact means that former

Figure 18. Illustration of electron−hole orbitals in the PET process for 15 excitation states in LIII·Er (5).

PETs, which are from chelator to fluorophore have been disconnected after complexation. Most of these PETs are longrange, in which the calculated distance of this electron transfer is 12.8 Å in 595.5 nm. This reason has made NO3− ion display electron transfer in all ranges of energy and to cause redshift in comparison to free ligand in the emission spectrum. Thermogravimetric Analysis and Powder X-ray Diffraction. The thermal gravimetric analyses (TGA) were performed on 1−5 to examine the thermal stability of the complexes with a heating rate of 10 °C min−1 in the temperature range of 30−1000 °C under N2 atmosphere. TGA curves of all complexes have similar profiles, displaying one main weight loss step until the decomposition of the

■

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.8b03611. L


Article

Inorganic Chemistry

with 4, 5-bis (diphenylphosphino)-9, 9-dimethylxanthene oxide as a promising light-conversion molecular device. Dalton Trans. 2009, 0, 7519−7528. (d) Matsumoto, K.; Suzuki, K.; Tsukuda, T.; Tsubomura, T. A chiral 2, 6-bis (oxazolinyl) pyridine ligand with amide groups to form isomorphous complexes through all the lanthanoid series. Inorg. Chem. 2010, 49, 4717−4719. (e) Hu, X.; Dou, W.; Xu, C.; Tang, X.; Zheng, J.; Liu, W. Lanthanide radii controlled one-dimensional polymer and dinuclear complexes and their fluorescent properties. Dalton Trans. 2011, 40, 3412−3418. (f) Wang, K. Y.; Bassil, B. S.; Lin, Z.; Römer, I.; Vanhaecht, S.; ParacVogt, T. N.; Sáenz de Pipaón, C.; Galán-Mascarós, J. R.; Fan, L.; Cao, J.; et al. Ln12-Containing 60-Tungstogermanates: Synthesis, Structure, Luminescence, and Magnetic Studies. Chem. - Eur. J. 2015, 21, 18168−18176. (3) (a) Philip Horwitz, E.; Kalina, D. C.; Diamond, H.; Vandegrift, G. F.; Schulz, W. W. The truex process-a process for the extraction of the tkansuranic elements erom nitric AC in wastes utilizing modified purex solvent. Solvent Extr. Ion Exch. 1985, 3, 75−109. (b) Nash, K. L. A review of the basic chemistry and recent developments in trivalent felements separations. Solvent Extr. Ion Exch. 1993, 11, 729−768. (c) Harrowfield, J. M.; Mocerino, M.; Peachey, B. J.; Skelton, B. W.; White, A. H. Rare-earth-metal solvent extraction with calixarene phosphates. J. Chem. Soc., Dalton Trans. 1996, 0, 1687−1699. (d) Modolo, G.; Odoj, R. Synergistic selective extraction of actinides (III) over lanthanides from nitric acid using new aromatic diorganyldithiophosphinic acids and neutral organophosphorus compounds. Solvent Extr. Ion Exch. 1999, 17, 33−53. (e) Jenkins, A. L.; Uy, O. M.; Murray, G. M. Polymer-based lanthanide luminescent sensor for detection of the hydrolysis product of the nerve agent soman in water. Anal. Chem. 1999, 71, 373−378. (f) Modolo, G.; Nabet, S. Thermodynamic study on the synergistic mixture of bis (chlorophenyl) dithiophosphinic acid and tris (2ethylhexyl) phosphate for separation of actinides (III) from lanthanides (III). Solvent Extr. Ion Exch. 2005, 23, 359−373. (g) Panak, P. J.; Geist, A. Complexation and extraction of trivalent actinides and lanthanides by triazinylpyridine N-donor ligands. Chem. Rev. 2013, 113, 1199−1236. (4) Armelao, L.; Quici, S.; Barigelletti, F.; Accorsi, G.; Bottaro, G.; Cavazzini, M.; Tondello, E. Design of luminescent lanthanide complexes: From molecules to highly efficient photo-emitting materials. Coord. Chem. Rev. 2010, 254, 487−505. (5) Wiedemann, E. Ueber Fluorescenz und Phosphorescenz I. Abhandlung. Ann. Phys. 1888, 270, 446−463. (6) (b) Cotton, S. Lanthanide and Actinide Chemistry; John Wiley & Sons, 2013. (a) Weber, M. J. Lanthanide and Actinide Lasers. ACS Symposium Series 1980, 131, 275. (7) (a) Levine, A. K.; Palilla, F. C. A new, highly efficient redemitting cathodoluminescent phosphor (YVO4: Eu) for color television. Appl. Phys. Lett. 1964, 5, 118−120. (b) McColl, J.; Palilla, F. Use of Rare Earths in Television and Cathode Ray Phosphors; American Chemical Society: Washington, DC, 1981; Vol. 164, pp 177−193. (c) Reeh, U.; Höhn, K.; Stath, N.; Waitl, G.; Schlotter, P.; Schneider, J.; Schmidt, R. Light-radiating semiconductor component with a luminescence conversion element. U.S. Patent US9196800B2, 2015. (8) Bünzli, J.-C. G.; Piguet, C. Taking advantage of luminescent lanthanide ions. Chem. Soc. Rev. 2005, 34, 1048−1077. (9) (a) de Bettencourt-Dias, A. Lanthanide-based emitting materials in light-emitting diodes. Dalton Trans. 2007, 0, 2229−2241. (b) Li, J.; Yan, J.; Wen, D.; Khan, W. U.; Shi, J.; Wu, M.; Su, Q.; Tanner, P. A. Advanced red phosphors for white light-emitting diodes. J. Mater. Chem. C 2016, 4, 8611−8623. (10) (a) Binnemans, K. Lanthanide-Based Luminescent Hybrid Materials. Chem. Rev. 2009, 109, 4283−4374. (b) Allendorf, M. D.; Bauer, C. A.; Bhakta, R. K.; Houk, R. J. T. Luminescent metal− organic frameworks. Chem. Soc. Rev. 2009, 38, 1330−1352. (c) Hu, Z.; Deibert, B. J.; Li, J. Luminescent metal−organic frameworks for chemical sensing and explosive detection. Chem. Soc. Rev. 2014, 43, 5815−5840. (d) Rocha, J.; Carlos, L. D.; Paz, F. A. A.; Ananias, D.

Crystals data, SHAPE analysis data, HB and CH···π tables, conformational analysis of ligands and complexes, XPAC plots for 1 and 2, crystal structure pictures for 1, 2, and 3, the excitation spectra for ligands and complexes, PL spectra of LI, 1, and 2 in solution, EQY determination results for 1−5, TD-DFT pictures and tables, TG curves for 1−5, and PXRD patterns for LIII, 1−5 at RT (PDF) Accession Codes

CCDC 1450035, 1450511, 1450513, 1818556, 1818558, and 1818559 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing data_ [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Khodayar Gholivand: 0000-0001-8884-7895 Mahdieh Hosseini: 0000-0002-6289-2708 Yazdan Maghsoud: 0000-0002-4051-0844 Agata Owczarzak: 0000-0002-4427-3188 Author Contributions #

These authors contributed equally to this manuscript.

Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS Financial support of this work by Tarbiat Modares University Iran National Science Foundation (INSF) is gratefully acknowledged. J.V. acknowledges support from the Charles University Centre program UNCE/SCI/010.

■

REFERENCES

(1) (a) Morrow, J. R.; Buttrey, L. A.; Shelton, V. M.; Berback, K. A. Efficient catalytic cleavage of RNA by lanthanide (III) macrocyclic complexes: toward synthetic nucleases for in vivo applications. J. Am. Chem. Soc. 1992, 114, 1903−1905. (b) Wang, K.; Li, R.; Cheng, Y.; Zhu, B. Lanthanidesthe future drugs? Coord. Chem. Rev. 1999, 190, 297−308. (c) Hurst, P.; Takasaki, B. K.; Chin, J. Rapid cleavage of RNA with a La (III) dimer. J. Am. Chem. Soc. 1996, 118, 9982−9983. (d) Franklin, S. J. Lanthanide-mediated DNA hydrolysis. Curr. Opin. Chem. Biol. 2001, 5, 201−208. (e) Silverman, A. P.; Kool, E. T. Detecting RNA and DNA with templated chemical reactions. Chem. Rev. 2006, 106, 3775−3789. (f) Krężel, A.; Lisowski, J. Enantioselective cleavage of supercoiled plasmid DNA catalyzed by chiral macrocyclic lanthanide (III) complexes. J. Inorg. Biochem. 2012, 107, 1−5. (g) Zhao, C.; Sun, Y.; Ren, J.; Qu, X. Recent progress in lanthanide complexes for DNA sensing and targeting specific DNA structures. Inorg. Chim. Acta 2016, 452, 50−61. (2) (a) Senegas, J.-M.; Bernardinelli, G.; Imbert, D.; Bünzli, J.-C. G.; Morgantini, P.-Y.; Weber, J.; Piguet, C. Connecting terminal carboxylate groups in nine-coordinate lanthanide podates: consequences on the thermodynamic, structural, electronic, and photophysical properties. Inorg. Chem. 2003, 42, 4680−4695. (b) Petit, S.; Baril-Robert, F.; Pilet, G.; Reber, C.; Luneau, D. Luminescence spectroscopy of europium (III) and terbium (III) penta-, octa-and nonanuclear clusters with β-diketonate ligands. Dalton Trans. 2009, 0, 6809−6815. (c) Ambili Raj, D.; Biju, S.; Reddy, M. 4,4,5,5,5Pentafluoro-1-(9H-fluoren-2-yl)-1,3-pentanedione complex of Eu3+ M


Article

Inorganic Chemistry Luminescent multifunctional lanthanides-based metal−organic frameworks. Chem. Soc. Rev. 2011, 40, 926−940. (11) Li, Z.; Zhu, G.; Guo, X.; Zhao, X.; Jin, Z.; Qiu, S. Synthesis, Structure, and Luminescent and Magnetic Properties of Novel Lanthanide Metal−Organic Frameworks with Zeolite-like Topology. Inorg. Chem. 2007, 46, 5174−5178. (12) Galaup, C.; Picard, C.; Cathala, B.; Cazaux, L.; Tisnès, P.; Autiero, H.; Aspe, D. Mono(di)nuclear Europium(III) Complexes of Macrobi(tri)cyclic Cryptands Derived from Diazatetralactams as Luminophores in Aqueous Solution. Helv. Chim. Acta 1999, 82, 543−560. (13) (a) Li, H.-F.; Yan, P.-F.; Chen, P.; Wang, Y.; Xu, H.; Li, G.-M. Highly luminescent bis-diketone lanthanide complexes with triplestranded dinuclear structure. Dalton Trans. 2012, 41, 900−907. (b) Sun, W.-B.; Han, B.-L.; Lin, P.-H.; Li, H.-F.; Chen, P.; Tian, Y.M.; Murugesu, M.; Yan, P.-F. Series of dinuclear and tetranuclear lanthanide clusters encapsulated by salen-type and β-diketionate ligands: single-molecule magnet and fluorescence properties. Dalton Trans. 2013, 42, 13397−13403. (c) Li, H.-F.; Li, G.-M.; Chen, P.; Sun, W.-B.; Yan, P.-F. Highly luminescent lanthanide complexes with novel bis-β-diketone ligand: Synthesis, characterization and photoluminescent properties. Spectrochim. Acta, Part A 2012, 97, 197−201. (d) Shi, J.; Hou, Y.; Chu, W.; Shi, X.; Gu, H.; Wang, B.; Sun, Z. Crystal Structure and Highly Luminescent Properties Studies of Bis-βdiketonate Lanthanide Complexes. Inorg. Chem. 2013, 52, 5013− 5022. (e) Zhu, T.; Chen, P.; Li, H.; Sun, W.; Gao, T.; Yan, P. Structural effects on the photophysical properties of mono-βdiketonate and bis-β-diketonate EuIII complexes. Phys. Chem. Chem. Phys. 2015, 17, 16136−16144. (14) (a) Shi, P.-f.; Chen, Z.; Xiong, G.; Shen, B.; Sun, J.-Z.; Cheng, P.; Zhao, B. Structures, Luminescence, and Magnetic Properties of Several Three-Dimensional Lanthanide−Organic Frameworks Comprising 4-Carboxyphenoxy Acetic Acid. Cryst. Growth Des. 2012, 12, 5203−5210. (b) Wang, P.; Fan, R.; Yang, Y.; Liu, X.; Cao, W.; Yang, B. Synthesis, crystal structures and properties of lanthanide-organic frameworks based benzene carboxylates with two/three-dimensional structure. J. Solid State Chem. 2012, 196, 441−450. (c) Zou, J.-H.; Zhu, D.-L.; Li, F.-F.; Li, F.-S.; Wu, H.; Li, Q.-Y.; Yang, G.-W.; Zhang, P.; Miao, Y.-X.; Xie, J. Three New Coordination Compounds with Neodymium Based on Tetrazole Containing Carboxylic Acid Ligands. Z. Anorg. Allg. Chem. 2014, 640, 2226−2231. (d) Zhang, F.; Yan, P.; Zou, X.; Zhang, J.; Hou, G.; Li, G. Novel 3D Alkali−Lanthanide Heterometal−Organic Frameworks with Pyrazine-2,3,5,6-tetracarboxylic Acid: Synthesis, Structure, and Magnetism. Cryst. Growth Des. 2014, 14, 2014−2021. (15) (a) Charbonnière, L. J.; Ziessel, R.; Montalti, M.; Prodi, L.; Zaccheroni, N.; Boehme, C.; Wipff, G. Luminescent lanthanide complexes of a bis-bipyridine-phosphine-oxide ligand as tools for anion detection. J. Am. Chem. Soc. 2002, 124, 7779−7788. (b) Vicente, J. A.; Mlonka, A.; Gunaratne, H. N.; Swadźba-Kwaśny, M.; Nockemann, P. Phosphine oxide functionalised imidazolium ionic liquids as tuneable ligands for lanthanide complexation. Chem. Commun. 2012, 48, 6115−6117. (c) Platt, A. W. Lanthanide phosphine oxide complexes. Coord. Chem. Rev. 2017, 340, 62−78. (d) Bannister, R. D.; Levason, W.; Light, M. E.; Reid, G. Tertiary phosphine oxide complexes of lanthanide diiodides and dibromides. Polyhedron 2018, 154, 259−262. (16) (a) Fang, Y.-P.; Xu, A.-W.; Song, R.-Q.; Zhang, H.-X.; You, L.P.; Yu, J. C.; Liu, H.-Q. Systematic synthesis and characterization of single-crystal lanthanide orthophosphate nanowires. J. Am. Chem. Soc. 2003, 125, 16025−16034. (b) Massue, J.; Quinn, S. J.; Gunnlaugsson, T. Lanthanide luminescent displacement assays: the sensing of phosphate anions using Eu (III)− Cyclen-conjugated gold nanoparticles in aqueous solution. J. Am. Chem. Soc. 2008, 130, 6900− 6901. (c) Goura, J.; Walsh, J. P.; Tuna, F.; Halder, R.; Maji, T. K.; Chandrasekhar, V. P−C Bond Cleavage-Assisted Lanthanide Phosphate Coordination Polymers. Cryst. Growth Des. 2015, 15, 2555−2560. (d) Jordan, N.; Demnitz, M.; Lösch, H.; Starke, S.; Brendler, V.; Huittinen, N. Complexation of Trivalent Lanthanides

(Eu) and Actinides (Cm) with Aqueous Phosphates at Elevated Temperatures. Inorg. Chem. 2018, 57, 7015−7024. (17) Shuvaev, S.; Utochnikova, V.; Marciniak, Ł.; Freidzon, A.; Sinev, I.; Van Deun, R.; Freire, R. O.; Zubavichus, Y.; Grünert, W.; Kuzmina, N. Lanthanide complexes with aromatic o-phosphorylated ligands: synthesis, structure elucidation and photophysical properties. Dalton Trans. 2014, 43, 3121−3136. (18) (a) Alcock, N. W.; Roberts, M. M.; Brown, D. Actinide structural studies. Part 1. Crystal and molecular structures of dinitratodioxobis (triphenylphosphine oxide) neptunium (VI), dinitratodioxobis (triphenylphosphine oxide) uranium (VI), and dichlorodioxo-(triphenylphosphine oxide) neptunium (VI). J. Chem. Soc., Dalton Trans. 1982, 0, 25−31. (b) Hill, N. J.; Leung, L.-S.; Levason, W.; Webster, M. Homoleptic octahedral hexakis (trimethylphosphine oxide) lanthanide hexafluorophosphates,[Ln(Me3PO)6][PF6]3:: synthesis, structures and properties. Inorg. Chim. Acta 2003, 343, 169−174. (c) Berthet, J.-C.; Nierlich, M.; Ephritikhine, M. A comparison of analogous 4f-and 5f-element compounds: syntheses and crystal structures of triphenylphosphine oxide complexes of lanthanide (III) and uranium (III) triflates and iodides [MX2(OPPh3)4][X](X= OTf and M= Ce or U; X= I and M= Nd, Ce, La, U). Polyhedron 2003, 22, 3475−3482. (d) Glazier, M. J.; Levason, W.; Matthews, M. L.; Thornton, P. L.; Webster, M. Synthesis, properties and solution speciation of lanthanide chloride complexes of triphenylphosphine oxide. Inorg. Chim. Acta 2004, 357, 1083−1091. (e) Berthon, C.; Boubals, N.; Charushnikova, I. A.; Collison, D.; Cornet, S. p. M.; Den Auwer, C.; Gaunt, A. J.; Kaltsoyannis, N.; May, I.; Petit, S.; et al. The Reaction Chemistry of Plutonyl (VI) Chloride Complexes with Triphenyl Phosphineoxide and Triphenyl Phosphinimine. Inorg. Chem. 2010, 49, 9554−9562. (f) Schnaars, D. D.; Wilson, R. E. Synthesis, Structure, and Vibrational Properties of [Ph4P]2NpO2Cl4 and [Ph4P] 2PuO2Cl4 Complexes. Inorg. Chem. 2018, 57, 3008−3016. (g) G. Leach, E.; Shady, J. R.; Boyden, A. C.; Emig, A.-l.; Henry, A. T.; Connor, E. K.; Staples, R. J.; Schaertel, S.; Werner, E. J.; Biros, S. M. X-ray crystallographic, luminescence and NMR studies of phenacyldiphenylphosphine oxide with the Ln (III) ions Sm, Eu, Gd, Tb and Dy. Dalton Trans. 2017, 46, 15458−15469. (19) (a) Matonic, J. H.; Neu, M. P.; Enriquez, A. E.; Paine, R. T.; Scott, B. L. Synthesis and crystal structure of a ten-coordinate plutonium (IV) ion complexed by 2-[(diphenylphosphino) methyl] pyridine N, P-dioxide:[Pu(NO 3 ) 3 {2-[(C 6 H 5 ) 2 P(O)CH 2 ]C 5 H4NO}2][Pu(NO3)6]0.5. J. Chem. Soc., Dalton Trans. 2002, 0, 2328−2332. (b) Lees, A. M.; Platt, A. W. Complexes of lanthanide nitrates with bis (diphenylphosphino) methane dioxide. Inorg. Chem. 2003, 42, 4673−4679. (c) Paine, R. T.; Bond, E. M.; Parveen, S.; Donhart, N.; Duesler, E. N.; Smith, K. A.; Nöth, H. Synthesis and Coordination Properties of 1-(Diphenylphosphine oxide)-1-(2 ′-pyridyl N-oxide)-3-(diphenylphosphine oxide) propane. Inorg. Chem. 2002, 41, 444−448. (d) Gan, X.-M.; T. Paine, R.; Duesler, E. N.; Nöth, H. Synthesis and coordination chemistry of arene soluble 4-alkyl-2, 6-bis [(diphenylphosphino) methyl] pyridine N, P, P′trioxide ligands. Dalton Trans. 2003, 0, 153−159. (e) Spichal, Z.; Necas, M.; Pinkas, J.; Novosad, J. The Synthesis and Crystal Structures of Two-Dimensional Coordination Polymers of Ph2P (O)−CH2CH2−P(O)Ph2 and Ph2P(O)−C5H3N−P(O)Ph2 with Praseodymium. Inorg. Chem. 2004, 43, 2776−2778. (f) Binyamin, I.; Pailloux, S.; Duesler, E. N.; Rapko, B. M.; Paine, R. T. Synthesis and Lanthanide Coordination Properties of New 2, 6-Bis (N-tertbutylacetamide) pyridine and 2, 6-Bis (N-tert-butylacetamide) pyridine-N-oxide Ligands. Inorg. Chem. 2006, 45, 5886−5892. (g) Kannan, S.; Moody, M. A.; Barnes, C. L.; Duval, P. B. Fluoride abstraction and reversible photochemical reduction of cationic uranyl (VI) phosphine oxide complexes. Inorg. Chem. 2006, 45, 9206−9212. (h) Kealey, S.; Long, N. J.; White, A. J.; Gee, A. D. A novel tetrakis (pyrazolyl) borate ligand bearing triphenylphosphine oxide substituents. Dalton Trans. 2007, 0, 4763−4765. (i) Spencer, L. P.; Yang, P.; Scott, B. L.; Batista, E. R.; Boncella, J. M. Uranium (VI) bis (imido) chalcogenate complexes: Synthesis and density functional theory analysis. Inorg. Chem. 2009, 48, 2693−2700. N


Article

Inorganic Chemistry (20) (a) Schurhammer, R.; Erhart, V.; Troxler, L.; Wipff, G. Interaction of M3+ lanthanide cations with phosphoryl containing (alkyl)3 PO versus (alkyl-O)3PO ligands: steric effects are more important than basicity effects. J. Chem. Soc., Perkin Trans. 2 1999, 999, 2423−2431. (b) Berny, F.; Muzet, N.; Troxler, L.; Dedieu, A.; Wipff, G. Interaction of M3+ Lanthanide Cations with Amide, Pyridine, and Phosphoryl OPPh3 Ligands: A Quantum Mechanics Study. Inorg. Chem. 1999, 38, 1244−1252. (21) Xu, H.; Wang, L.-H.; Zhu, X.-H.; Yin, K.; Zhong, G.-Y.; Hou, X.-Y.; Huang, W. Application of Chelate Phosphine Oxide Ligand in EuIII Complex with Mezzo Triplet Energy Level, Highly Efficient Photoluminescent, and Electroluminescent Performances. J. Phys. Chem. B 2006, 110, 3023−3029. (22) Gholivand, K.; Mahzouni, H. R.; Esrafili, M. D. How do phosphoramides compete with phosphine oxides in lanthanide complexation? Structural, electronic and energy aspects at ab initio and DFT levels. Theor. Chem. Acc. 2010, 127, 539−550. (23) Gholivand, K.; Mahzouni, H. R.; Pourayoubi, M.; Amiri, S. High-coordinated lanthanum (III) complexes with new mono-and bidentate phosphoryl donors; spectroscopic and structural aspects. Inorg. Chim. Acta 2010, 363, 2318−2324. (24) Nguyen, C.; Kim, J. Thermal stabilities and flame retardancies of nitrogen−phosphorus flame retardants based on bisphosphoramidates. Polym. Degrad. Stab. 2008, 93, 1037−1043. (25) Gholivand, K.; Mahzouni, H. R.; Esrafili, M. D. Structure, bonding, electronic and energy aspects of a new family of early lanthanide (La, Ce and Nd) complexes with phosphoric triamides: Insights from experimental and DFT studies. Dalton Trans. 2012, 41, 1597−1608. (26) (a) Gholivand, K.; Gholami, A.; Ebrahimi, A. A. V.; Abolghasemi, S. T.; Esrafili, M. D.; Fadaei, F. T.; Schenk, K. J. Triphenyltin(iv) adducts of diphosphoryl ligands: structural, electronic and energy aspects from X-ray crystallography and theoretical calculations. RSC Adv. 2015, 5, 17482−17492. (b) Gholivand, K.; EbrahimiValmoozi, A. A.; Gholami, A.; Dusek, M.; Eigner, V.; Abolghasemi, S. Synthesis, characterization, crystal structures, QSAR study and antibacterial activities of organotin bisphosphoramidates. J. Organomet. Chem. 2016, 806, 33−44. (27) Sheldrick, G. SHELXL-2013; University of Gö ttingen, Göttingen, Germany, 2013. (28) Sheldrick, G. SHELXL97: Program for the Refinement of Crystal Structures; University of Göttingen, Göttingen, Germany, 1997. (29) Spek, A. PLATON SQUEEZE: a tool for the calculation of the disordered solvent contribution to the calculated structure factors. Acta Crystallogr., Sect. C: Struct. Chem. 2015, 71, 9−18. (30) Valenta, J. Determination of absolute quantum yields of luminescing nanomaterials over a broad spectral range: from the integrating sphere theory to the correct methodology. Nanosci. Methods 2014, 3, 11−27. (31) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. A.; Nakatsuji, H.; Caricato, M.; Li, X.; Hratchian, H. P.; Izmaylov, A. F.; Bloino, J.; Zheng, G.; Sonnenberg, J. L.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.; Montgomery, J. A., Jr.; Peralta, J. E.; Ogliaro, F.; Bearpark, M.; Heyd, J. J.; Brothers, E.; Kudin, K. N.; Staroverov, V. N.; Kobayashi, R.; Normand, J.; Raghavachari, K.; Rendell, A.; Burant, J. C.; Iyengar, S. S.; Tomasi, J.; Cossi, M.; Rega, N.; Millam, J. M.; Klene, M.; Knox, J. E.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Martin, R. L.; Morokuma, K.; Zakrzewski, V. G.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Dapprich, S.; Daniels, A. D.; Farkas, O.; Foresman, J. B.; Ortiz, J. V.; Cioslowski, J.; Fox, D. J. Gaussian 09, revision A.01; Gaussian, Inc.: Wallingford, CT, 2009. (32) (a) Zhao, Y.; Truhlar, D. G. Density functional for spectroscopy: no long-range self-interaction error, good performance for Rydberg and charge-transfer states, and better performance on average than B3LYP for ground states. J. Phys. Chem. A 2006, 110,

13126−13130. (b) Vlček, A., Jr; Záliš, S. Modeling of charge-transfer transitions and excited states in d6 transition metal complexes by DFT techniques. Coord. Chem. Rev. 2007, 251, 258−287. (c) Stein, T.; Kronik, L.; Baer, R. Reliable prediction of charge transfer excitations in molecular complexes using time-dependent density functional theory. J. Am. Chem. Soc. 2009, 131, 2818−2820. (d) Li, R.; Zheng, J.; Truhlar, D. G. Density functional approximations for charge transfer excitations with intermediate spatial overlap. Phys. Chem. Chem. Phys. 2010, 12, 12697−12701. (e) Steinmann, S. N.; Piemontesi, C.; Delachat, A.; Corminboeuf, C. Why are the interaction energies of charge-transfer complexes challenging for DFT? J. Chem. Theory Comput. 2012, 8, 1629−1640. (33) Tawada, Y.; Tsuneda, T.; Yanagisawa, S.; Yanai, T.; Hirao, K. A long-range-corrected time-dependent density functional theory. J. Chem. Phys. 2004, 120, 8425−8433. (34) Martin, J. M.; Sundermann, A. Correlation consistent valence basis sets for use with the Stuttgart−Dresden−Bonn relativistic effective core potentials: The atoms Ga−Kr and In−Xe. J. Chem. Phys. 2001, 114, 3408−3420. (35) Dolg, M.; Stoll, H.; Preuss, H. A combination of quasirelativistic pseudopotential and ligand field calculations for lanthanoid compounds. Theor. Chim. Acta 1993, 85, 441−450. (36) Yang, J.; Dolg, M. Valence basis sets for lanthanide 4f-in-core pseudopotentials adapted for crystal orbital ab initio calculations. Theor. Chem. Acc. 2005, 113, 212−224. (37) Dolg, M.; Stoll, H.; Savin, A.; Preuss, H. Energy-adjusted pseudopotentials for the rare earth elements. Theor. Chim. Acta 1989, 75, 173−194. (38) Dennington, R. D.; Keith, T. A.; Millam, J. M. GaussView 5.0.8; Gaussian Inc., 2008. (39) Llunell, M.; Casanova, D.; Cirera, J.; Alemany, P.; Alvarez, S. SHAPE: Program for the Stereochemical Analysis of Molecular Fragments by Means of Continuous Shape Measures and Associated Tools; University of Barcelona: Barcelona, 2010. (40) (a) Gelbrich, T.; Hursthouse, M. B. Systematic investigation of the relationships between 25 crystal structures containing the carbamazepine molecule or a close analogue: a case study of the XPac method. CrystEngComm 2006, 8, 448−460. (b) Fabbiani, F. P.; Dittrich, B.; Florence, A. J.; Gelbrich, T.; Hursthouse, M. B.; Kuhs, W. F.; Shankland, N.; Sowa, H. Crystal structures with a challenge: highpressure crystallisation of ciprofloxacin sodium salts and their recovery to ambient pressure. CrystEngComm 2009, 11, 1396−1406. (41) Veerashekhar Goud, E.; Sivaramakrishna, A.; Vijayakrishna, K.; Brahmmananda Rao, C. V. S.; Khedkar, V. M.; Jha, P. C. Synthesis, structure and DNA interaction studies of bisphosphoramides: Theoretical and experimental insights. Inorg. Chim. Acta 2017, 461, 84−91. (42) (a) Siekierski, S. The itinerant character of 4f orbitals in lanthanide metals by a comparison of lanthanide contraction in metals and ionic compounds. Inorg. Chim. Acta 1985, 109, 199−201. (b) Chatterjee, A.; Maslen, E.; Watson, K. The effect of the lanthanoid contraction on the nonaaqualanthanoid (III) tris (trifluoromethanesulfonates). Acta Crystallogr., Sect. B: Struct. Sci. 1988, 44, 381−386. (43) Xu, W.; Zhou, Y.; Huang, D.; Xiong, W.; Su, M.; Wang, K.; Han, S.; Hong, M. Crystal structure, multiplex photoluminescence, and magnetic properties of a series of lanthanide coordination polymers based on quinoline carboxylate ligand. Cryst. Growth Des. 2013, 13, 5420−5432. (44) Zhang, X.-T.; Fan, L.-M.; Fan, W.-L.; Li, B.; Liu, G.-Z.; Liu, X.Z.; Zhao, X. A series of lanthanide coordination polymers based on designed bifunctional 1, 4-Bis (imidazol-1-yl) terephthalic acid ligand: structural diversities, luminescence, and magnetic properties. Cryst. Growth Des. 2016, 16, 3993−4004. (45) (a) Aillaud, I.; Collin, J.; Duhayon, C.; Guillot, R.; Lyubov, D.; Schulz, E.; Trifonov, A. New Chiral Lanthanide Amide Ate Complexes for the Catalysed Synthesis of Scalemic NitrogenContaining Heterocycles. Chem. - Eur. J. 2008, 14, 2189−2200. O


Article

Inorganic Chemistry (b) Cui, Y.; Yue, Y.; Qian, G.; Chen, B. Luminescent functional metal−organic frameworks. Chem. Rev. 2012, 112, 1126−1162. (46) Lu, W.-G.; Zhong, D.-C.; Jiang, L.; Lu, T.-B. Lanthanide coordination polymers constructed from Imidazole-4, 5-dicarboxylate and sulfate: syntheses, structural diversity, and photoluminescent properties. Cryst. Growth Des. 2012, 12, 3675−3683. (47) (a) Wang, X.; Zhai, Q.-G.; Li, S.-N.; Jiang, Y.-C.; Hu, M.-C. Synthesis, Crystal Structures, and Solid-State Luminescent Properties of Diverse Ln−Pyridine-3, 5-Dicarboxylate Coordination Polymers Modulated by the Ancillary Ligand. Cryst. Growth Des. 2014, 14, 177−188. (b) Xu, B.; Cheng, Y.; Hu, H.-M.; Bai, C.; Wang, X.; Yang, M.-L.; Xue, G. Syntheses, crystal structures and luminescence properties of lanthanide-based coordination polymers constructed from a functionalized terpyridyl carboxylate ligand. CrystEngComm 2016, 18, 4613−4626. (48) (a) Hohenberg, P.; Kohn, W. Inhomogeneous electron gas. Phys. Rev. 1964, 136, B864−B871. (b) Runge, E.; Gross, E. K. Density-functional theory for time-dependent systems. Phys. Rev. Lett. 1984, 52, 997−1000. (49) (a) Petersilka, M.; Gossmann, U.; Gross, E. Excitation energies from time-dependent density-functional theory. Phys. Rev. Lett. 1996, 76, 1212−1215. (b) Scalmani, G.; Frisch, M. J.; Mennucci, B.; Tomasi, J.; Cammi, R.; Barone, V. Geometries and properties of excited states in the gas phase and in solution: Theory and application of a time-dependent density functional theory polarizable continuum model. J. Chem. Phys. 2006, 124, 094107.

P


Relations between Structural and Luminescence Properties of Novel

Recommend Documents