2-diphenylphosphino Phenyl Research Articles

Influence of different solvents on structures and electronic properties of new Fe2S2 complexes containing bis(2-diphenylphosphinophenyl)ether

In order to observe solvent effects on structures and properties of [FeFe]-hydrogenase, two Fe2S2 complexes, [Fe2(μ-pdt)(CO)4(DPEphos)] • CH2Cl2 (1) and [Fe2(μ-pdt)(CO)4 (DPEphos)] •[Fe2 (μ-pdt)(CO)4 (DPEphos)] (2) (DPEphos =bis(2-diphenyl phosphinophenyl)ether), have been prepared and characterized by IR, 1H NMR, 31P NMR, TG and X-ray crystal structure analysis. Structural analysis shows that the [Fe2(μ-pdt)(CO)4(DPEphos)] unit in 1 and 2 includes a butterfly Fe2S2 core, in which each iron atom is five-coordinated with a pseudo-square pyramidal geometry, and the change of the crystallization solvent from CH2Cl2 to toluene leads to the variation of crystallographic system, space group and the weak interactions. DFT studies indicate that the component of the HOMOs and LUMOs at different solvents for [Fe2(μ-pdt)(CO)4(DPEphos)] are nearly identical, which are primarily composed of CO, μ-pdt, Fe atoms and -Ph2P groups, coinciding with the change of DOS and PDOS at different solvents. Meanwhile, the HOMO and LUMO energies, HOMO → LUMO energy gap and Mülliken atomic charges at methanol, ethanol, dichloromethane and nitrobenzene are only a little change, which have much more changes than the relevant values at solvent-free model. All these show that the solvent has an important influence on structures and electronic properties of Fe2S2 complexes.

Structural characterization, electronic and luminescent properties of copper(I) complexes with different temperatures and their application to light-emitting diodes

Three Cu(I) complexes, [Cu(dppb)(bbim)]BF4(1), [Cu(DPEphos)(bbim)]BF4 (2) and [Cu (Xantphos)(bbim)]BF4(3) (dppb =1, 2-bis(diphenylphosphino)benzene, DPEphos=bis(2-diphenyl phosphinophenyl)ether, Xantphos=9, 9-dimethyl-bis(diphenylphosphino)xanthenes, bbim = bisbenzimidazole), have been synthesized and characterized by IR, 1H NMR, 31P NMR, TG, XRD elemental analysis and X-ray crystal structure analysis. The structural analysis indicates that the increases in the temperature from 100 K to 300 K result in the change of bond lengths, bond angles and the weak interactions. Theoretical calculations demonstrate that the HOMO → LUMO energy gap and Mülliken atomic charges are increased or shorten by increasing temperature from 100 K to 300 K, in according with the change of bond lengths and angles, while the composition of HOMO and LUMO orbitals are nearly unchanged at different temperatures. Meanwhile, the solid-state luminescent properties of these copper(I) complexes at 100 K, 200 K and 300 K also exhibit that the change of temperature leads to the variation of the Kr, Knr, τ, Фem and λmax, having a certain degree of consistency with the related calculation results. In these complexes, the maximum phosphorescent lifetime and quantum yield are up to 309 μs and 23% at 300 K, respectively. Moreover, to estimate potential application of copper(I) complexes for LED, monochromatic and white LED have been fabricated, respectively, showing reasonable electroluminescence with the maximum external quantum efficiency 3.95% and 5.31%.

Oligophosphine-thiocyanate Copper(I) and Silver(I) Complexes and Their Borane Derivatives Showing Delayed Fluorescence.

The series of chelating phosphine ligands, which contain bidentate P2 (bis[(2-diphenylphosphino)phenyl] ether, DPEphos; 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene, Xantphos; 1,2-bis(diphenylphosphino)benzene, dppb), tridentate P3 (bis(2-diphenylphosphinophenyl)phenylphosphine), and tetradentate P4 (tris(2-diphenylphosphino)phenylphosphine) ligands, was used for the preparation of the corresponding dinuclear [M(μ2-SCN)P2]2 (M = Cu, 1, 3, 5; M = Ag, 2, 4, 6) and mononuclear [CuNCS(P3/P4)] (7, 9) and [AgSCN(P3/P4)] (8, 10) complexes. The reactions of P4 with silver salts in a 1:2 molar ratio produce tetranuclear clusters [Ag2(μ3-SCN)(t-SCN)(P4)]2 (11) and [Ag2(μ3-SCN)(P4)]22+ (12). Complexes 7–11 bearing terminally coordinated SCN ligands were efficiently converted into derivatives 13–17 with the weakly coordinating –SCN:B(C6F5)3 isothiocyanatoborate ligand. Compounds 1 and 5–17 exhibit thermally activated delayed fluorescence (TADF) behavior in the solid state. The excited states of thiocyanate species are dominated by the ligand to ligand SCN → π(phosphine) charge transfer transitions mixed with a variable contribution of MLCT. The boronation of SCN groups changes the nature of both the S1 and T1 states to (L + M)LCT d,p(M, P) → π(phosphine). The localization of the excited states on the aromatic systems of the phosphine ligands determines a wide range of luminescence energies achieved for the title complexes (λem varies from 448 nm for 1 to 630 nm for 10c). The emission of compounds 10 and 15, based on the P4 ligand, strongly depends on the solid-state packing (λem = 505 and 625 nm for two crystalline forms of 15), which affects structural reorganizations accompanying the formation of electronically excited states.