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Two type lanthanide complexes obtained by salen-type ligand N,N'-ethylenebis(salicylideneimine) (HL) and N,N'-ethylene-bis(3-methoxysalicylideneimine) (HL) have been isolated. They are 2D coordination polymer [Yb(HL)(NO)] ( 1), mononuclear Ln(HL)(NO) [Ln = Sm ( 2), Ho ( 3)]. The structures of 1- 3 were determined by single crystal X-ray crystallographic studies and their photophysical properties were investigated. [ABSTRACT FROM AUTHOR]

Three dinuclear lanthanide complexes are achieved by using H2salen or H2salen/acac ligands (H2salen = N,N′-ethylenebis(salicylideneimine), acac = acetylacetonate). They are homodinuclear [Er2(salen)3] (1), [Yb2(salen)2(acac)2] (2), and heterodinuclear geometrical [ErYb(salen)2(acac)2] (3). The structures of complexes were determined by single crystal X-ray crystallographic studies and their photophysical properties were investigated. The homonuclear Yb2 complex exhibits characteristic metal-centered NIR emission. The geometric ErYb isomer exhibits ‘dual emissions’ from both erbium(iii) and ytterbium(iii) ions. There was no detectable photoluminescence in the Er2 complex, not only in solid state but also in solvent. [ABSTRACT FROM AUTHOR]

Herein, a series of ionic mononuclear Cu(I) complexes, [Cu(phen)(bdppmapy)]Cl (1a), [Cu(phen)(bdppmapy)]Br (2a), [Cu(phen)(bdppmapy)]I (3a), [Cu(phen)(bdppmapy)]SCN (4a), [Cu(Dpq)(bdppmapy)]Cl (1b), [Cu(Dpq)(bdppmapy)]Br (2b), [Cu(Dpq)(bdppmapy)]I (3b) and [Cu(Dpq)(bdppmapy)]SCN (4b) {phen = [1,10]phenanthroline; Dpq = pyrazino[2,3-f][1,10]-phenanthroline; bdppmapy = N,N-bis((diphenylphosphino)methyl)-2-pyridinamine} have been synthesized and characterized by using IR, NMR, elemental analysis, single crystal X-ray diffraction analysis, fluorescence spectroscopy methods, and UV-vis and terahertz (THz) time-domain absorption spectroscopy. Their crystal structures were elucidated by X-ray crystallography and their photophysical properties were investigated in detail. All the above complexes exhibit a 1D to 3D supramolecular structure which is linked together by intermolecular weak interaction forces and hydrogen bonds. By regulating ligands and anions, the emission wavelengths of these complexes are quite different in the range from 533 nm to 604 nm. Theoretical calculations and photophysical properties indicate that luminescence is derived from metal-to-ligand charge transfer (MLCT) excited states. In the meantime, the results of calculations show that the stabilization of the increased conjugation of the ligand-based π* orbital is ascribed to the observed bathochromic-shift in the MLCT transitions. [ABSTRACT FROM AUTHOR]

The luminescence properties of the tetranuclear bimetallic lanthanide complexes Sm2Eu2 ( 1) and Eu2Tb2 ( 2), were compared with those of the analogous homometallic complexes [Sm4(μ3-OH)2(salen)2(acac)6(CH3OH)2] ·CH3OH ( 3) and [Eu4(μ3-OH)2(salen)2(acac)6(CH3OH)2] ( 4) [H2salen = N, N′-ethylenebis(salicylideneimine), Hacac = acetylacetonate]. X-ray crystallographic analysis reveals that complexes 3 and 4 have planar tetranuclear structures. For the Eu2Tb2 configurational isomer, the TbIII ion in complex 2 mainly serves as a sensitizer. The quantum yields and lifetime measurements for 2 support the premise that Ln/ Ln energy transfer occurs in such lanthanide bimetallic complexes, along with the usual ligand-to-metal triplet energy pathways. Complexes 3 and 4 exhibit the characteristic metal-centered emission. [ABSTRACT FROM AUTHOR]

The synthesis of four heteroleptic dinuclear Cu(I) complexes bearing tetraphosphine and diimine ligands was reported. Complexes 1–3 were successfully obtained through microwave synthesis while complex 4 was synthesized through traditionally stirring at room temperature. These complexes are listed as follows: [Cu2(Dpq)2(dppeda)](ClO4)2·1.5CH2Cl2 (1), [Cu2(neo)2(dppeda)](ClO4)2·1.3CH2Cl2·1.7C4H10O (2), [Cu2(batho)2(dppeda)](ClO4)2·C4H10O (3), and [Cu2(batho)2(dpppda)](ClO4)2·3CH2Cl2 (4) {(Dpq = pyrazino[2,3-f][1,10]phenanthroline, batho = 4,7-diphenyl-1,10-phenanthroline, neo = 2,9-dimethyl-1,10-phenanthroline, dppeda = N1,N1,N2,N2-tetrakis[(diphenylphosphino)methyl]-1,2-ethanediamine, and dpppda = N1,N1,N4,N4-tetrakis[(diphenylphosphino)methyl]-1,4-benzenediamine}. Their crystal structures have been elucidated by X-ray crystallography and their photophysical properties have been investigated in detail. Photophysical studies and time domain density functional theory (TD-DFT) calculations show that the luminescence performance of these four complexes is ascribed to metal-to-ligand charge transfer (MLCT) mixed with ligand-to-ligand charge transfer (LLCT), and complex 2 shows green emission at 574 nm with the highest quantum yield of up to 52.80%. In addition, the research of photoluminescence properties under the guidance of terahertz spectroscopy technology leads to the preliminary discovery of a correlation between crystal packing and luminescence. It is found that the terahertz spectrum and absorption peak are strongly interdependent on C–H⋯π and π⋯π interactions, and the external weak interactions have negative effects on the luminescence performance. Herein, we predict that the terahertz spectroscopy analysis establishes a bridge between weak interactions (C–H⋯π and π⋯π interactions) and the photoluminescence properties, and puts forward a problem that should be noticed in designing Cu(I) complexes. [ABSTRACT FROM AUTHOR]

A series of novel lanthanide coordination polymers havebeen successfullysynthesized under hydrothermal or solvothermal conditions, namely,[Eu2(2,4′-bpdc)2(OH)(NO3)(H2O)3]n(1), [Ln(2,4′-bpdc)(1,4-bdc)0.5(DMF)-(H2O)·H2O]n[Ln = Eu (2); Ln = Pr (3); Ln = Nd (4)], [Ln(2,4′-bpdc)(DMF)2NO3]n[Ln = Eu (5); Ln = Nd (6); Ln = Gd (7)], and[Eu(2,4′-bpdc)(2,4′-Hbpdc)(H2O)]n(8), (2,4′-H2bpdc= 2,4′-biphenyldicarboxylic acid, 1,4-H2bdc = 1,4-benzenedicarboxylicacid, and DMF = N,N′-dimethylformamide).X-ray crystallographic studies reveal that 1featuresa three-dimensional (3D) framework with 45topology. 2–4, which are isostructural and synthesizedby using a mixture of 2,4′-H2bpdc and 1,4-H2bdc, exhibit two-dimensional (2D) (3,4)-connected net structures. 5–7show 2D layered structures containingdouble helix chains (Δ and Λ) with 44topology. 8possesses a 2D layered structure containing (4,6)-connectednetworks, which are connected by means of infinite zigzag chains linkedby 2,4′-bpdc2–and 2,4′-Hbpdc–anions. Furthermore, steady-state and time-resolvedspectroscopic measurements reveal that the four Eu(III) complexes, 1, 2, 5, and 8, exhibitremarkable red luminescence emissions with lifetimes at the millisecondscale. Complexes 4and 6display characteristicluminescent properties for Nd(III) in the near-infrared region. Thesinglet state and the lowest triplet level of ligand 2,4′-H2bpdc were calculated on the basis of the UV–vis absorbanceedges of ligand and the phosphorescence spectrum of Gd(III) complex 7. The energy transfer mechanisms in the lanthanide polymersare described and discussed. [ABSTRACT FROM AUTHOR]