Photoluminescence Spectra Of Complexes Research Articles

Preparation, spectroscopic and thermal investigation of fluorinated Sm(III) β-diketonates with bidentate N donor ligands

A series of samarium β-diketonates comprising nitrogen-heterocyclic auxiliary moiety were synthesized and characterized spectroscopically. A comprehensive analysis of complexes suggests the octacoordinated environment about samarium ion and similar structural behavior of complexes. The samarium ion is coordinated via carbonyl oxygen of diketone unit and nitrogen of neutral ligand. Energy band gap values of complexes lie in range of semiconducting materials. The photophysical properties of complexes were evaluated from photoluminescence spectra of complexes. By examining the energy transfer pathway and emission spectra, the sensitizing nature of chromophoric ligands is revealed. These synthesized complexes have shown peak around 649 nm (4G5/2→6H9/2) due to electric dipole transition. Results of luminescence spectra and colorimetric analysis have demonstrated the emission of synthesized samarium complexes in reddish orange region. The optical and photophysical properties of complexes claim the usefulness of prepared samarium complexes in designing display devices.

Two new Zn(II)/Cu(II) complexes based on bi- and tritopic 1,2,4-triazole derivatives with glutaric acid: Syntheses, structures, luminescent and magnetic properties

Two new Zn(II)/Cu(II) coordination polymers, [Zn(OPBT)(GA)]n (1) and {[Cu2TTPA(GA)2]·1.5H2O}n (2), have been successfully synthesized from flexible glutaric acid (H2GA) with different bi- and tritopic 1,2,4-triazole derivatives (OPBT=1.1′-(oxybis(1,4-phenylene))bis(1H-1,2,4-triazole), TTPA=tris(4-(1H-1,2,4-triazol-1-yl)phenyl)amine) and Zn(II)/Cu(II) nitrate salts. Their structures have been characterized by infrared spectra, elemental analyses, single crystal and powder X-ray diffraction analyses and thermogravimetric analyses. Both complexes 1 and 2 feature different 2D layers with sql topologies, which can be further arranged ABAB-type, leading to different 3D supramolecular frameworks by C-H···O hydrogen bonding or O-H···O/N hydrogen bonding/π···π stacking interactions. Moreover, the photoluminescence spectra of complex 1 are examined and variable-temperature magnetic susceptibility measurements of complex 2 reveal antiferromagnetic interactions between binuclear Cu(II) ions of paddle-wheel second building units (SBUs).

Synthesis, structures, luminescence and magnetism of nine lanthanide complexes with three-dimensional frameworks constructed from 2-(pyridyl-N-oxide)methylphosphonic acid and oxalic acid

To investigate the coordination nature of the pyridyl-N-oxide phosphonate ligands with rare earth metals, two series of nine lanthanide complexes, namely, {[Ln(HL)((C2O4)0.5)2(H2O)]·3H2O}n {Ln = Eu(1), Gd(2), Tb(3), Dy(4) and Ho(5)} and {[Ln2(L)(C2O4)2(H2O)3]·H2O}n {Ln = Er(6), Tm(7), Yb(8) and Lu(9)} {H2L = 2-(pyridyl-N-oxide)methylphosphonic acid; H2C2O4 = oxalic acid }, have been hydrothermally synthesized and characterized by IR spectroscopy, thermogravimetric analysis, and powder and single-crystal X-ray diffraction. Complexes 1–5 are isomorphic, featuring a three-dimensional (3D) porous structure with a dia topological framework, while the isomorphic complexes 6–9 show a 3D 3,4-connected topological framework with a point symbol of {72·8}2{73·83}. Photoluminescence spectra of complexes 1 and 3 exhibit the strong luminescence characteristic of Eu(III) and Tb(III) ions, respectively, suggesting that HL− and L2− anions are able to efficiently sensitize the luminescence of lanthanide ions. The magnetic analyses of complexes 2–5 show the characteristic magnetic susceptibilities of isolated Gd(III), Tb(III), Dy(III) and Ho(III) ions, respectively.

Synthesis, crystal structure and effect of deuterated solvents and temperature on visible and near infrared luminescence of N4-donor Schiff base lanthanide complexes

A series of lanthanide complexes [LnL(NO3)3]·CH3CN [Ln=Ce, (1•Ce); Nd, (2•Nd); Tb, (3•Tb); Dy, (4•Dy); Ho, (5•Ho); Er, (6•Er); Tm, (7•Tm); Yb (8•Yb)] have been synthesized by the reaction of N4 chelate ligand N,N'-bis(2-pyridinylmethylene)cyclohexane-1,2-diamine (L) with lanthanide salts. Photoluminescence spectra of complexes 2•Nd, 3•Tb, 4•Dy, and 8•Yb show the strong characteristic luminescence from visible to near infrared (NIR) region. Further, the singlet state (32,467cm−1) and the lowest triplet (23,202cm−1) energy level of L are calculated, indicating that the energy transfer from L to Tb3+ ion is more effective than that to Dy3+ ion. An extended work is developed to discuss on the effect of deuterated reagent and temperature on luminescent properties of 3•Tb and 8•Yb.

New homochiral ferroelectric supramolecular networks of complexes constructed by chiral S-naproxen ligand

Five new homochiral supramolecular networks of complexes, namely, [Ni(L)2(H2O)6]·2H2O (1), [Cu(L)2(H2O)3]·H2O (2), [Zn(L)2(H2O)2]·H2O (3), [Cd(L)2(H2O)2]·H2O (4) and [Cd(L)2(H2O)]n (5) [L = (S)-naproxen anion], have been prepared and structurally characterized by single crystal X-ray diffraction, powder X-ray diffraction (PXRD), elemental analysis, thermogravimetric analysis (TGA), and infrared (IR) spectroscopy. Complex 1 crystallizes in the space group P1, which is a mononuclear structure. In 1, there exists a variety of hydrogen bonding interactions, which further extend to a 3D supramolecular architecture. Complexes 2–4 crystallize in the space group C2, and all of them exhibit mononuclear structures. Intermolecular hydrogen bonding and C–H⋯π interactions are observed in complexes 2–4. Complex 5 crystallizes in the space group Cc, showing a one-dimensional chain structure. Hydrogen bonding (O–H⋯O) and weak stacking interactions (C–H⋯π) are also found. All of the complexes display significant ferroelectric properties and second harmonic generation response. Additionally, the photoluminescence spectra of complexes 3–5 have also been discussed.

Synthesis of heteroligand complex Nd(Phen){(iso-C4H9)2PS2}2(NO3). Crystal structure of [Nd(Phen){(iso-C4H9)2PS2}3] and luminescent properties of these compounds

The heteroligand complex Nd(Phen){(iso-C4H9)2PS2}2(NO3) (I) was synthesized and its IR spectrum was analyzed. The anions (iso-C4H9)2PS2/− and N3/− act as bidentate cyclic ligands. The single crystals of [Nd(Phen){iso-C4H9)2PS2}3] (II) were obtained on evaporation of a solution of complex I in a mixture CH2Cl2-hexane and were studied by X-ray diffraction. Crystals II are triclinic: a = 10.5509(5); b = 14.7432(8), c = 16.8503(10) A; α = 102.882(2)°, β = 97.211(2)°, γ= 108.087(2)°, V = 2374(2) A3, Z = 2, ρ(calcd.) = 1.332 g/cm3, space group \( P\bar 1 \). The coordination polyhedron of the Nd atom in a separate mononuclear molecule II is a distorted dodecahedron N2S6. The molecules are bound by weak van der Waals and π-π interactions. The photoluminescence spectra of complexes I, II were measured and interpreted.