56100-22-2Relevant academic research and scientific papers
Phosphane tuning in heteroleptic [Cu(N^N)(P^P)]+ complexes for light-emitting electrochemical cells
Brunner, Fabian,Babaei, Azin,Pertegás, Antonio,Junquera-Hernández, José M.,Prescimone, Alessandro,Constable, Edwin C.,Bolink, Henk J.,Sessolo, Michele,Ortí, Enrique,Housecroft, Catherine E.
, p. 446 - 460 (2019)
The synthesis and characterization of five [Cu(P^P)(N^N)][PF6] complexes in which P^P = 2,7-bis(tert-butyl)-4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (tBu2xantphos) or the chiral 4,5-bis(mesitylphenylphosphino)-9,9-dimethylxanthene (xantphosMes2) and N^N = 2,2′-bipyridine (bpy), 6-methyl-2,2′-bipyridine (6-Mebpy) or 6,6′-dimethyl-2,2′-bipyridine (6,6′-Me2bpy) are reported. Single crystal structures of four of the compounds confirm that the copper(i) centre is in a distorted tetrahedral environment. In [Cu(xantphosMes2)(6-Mebpy)][PF6], the 6-Mebpy unit is disordered over two equally populated orientations and this disorder parallels a combination of two dynamic processes which we propose for [Cu(xantphosMes2)(N^N)]+ cations in solution. Density functional theory (DFT) calculations reveal that the energy difference between the two conformers observed in the solid-state structure of [Cu(xantphosMes2)(6-Mebpy)][PF6] differ in energy by only 0.28 kcal mol?1. Upon excitation into the MLCT region (λexc = 365 nm), the [Cu(P^P)(N^N)][PF6] compounds are yellow to orange emitters. Increasing the number of Me groups in the bpy unit shifts the emission to higher energies, and moves the Cu+/Cu2+ oxidation to higher potentials. Photoluminescence quantum yields (PLQYs) of the compounds are low in solution, but in the solid state PLQYs of up to 59% (for [Cu(tBu2xantphos)(6,6′-Me2bpy)]+) are observed. Increased excited-state lifetimes at low temperature are consistent with the complexes exhibiting thermally activated delayed fluorescence (TADF). This is supported by the small energy difference calculated between the lowest-energy singlet and triplet excited states (0.17-0.25 eV). The compounds were tested in simple bilayer light-emitting electrochemical cells (LECs). The optoelectronic performances of complexes containing xantphosMes2 were generally lower with respect to those with tBu2xantphos, which led to bright and efficient devices. The best performing LECs were obtained for the complex [Cu(tBu2xantphos)(6,6′-Me2bpy)][PF6] due to the increased steric hindrance at the N^N ligand, resulting in higher PLQY.
A colorimetric and turn-on fluorescent chemosensor for selectively sensing Hg2+ and its resultant complex for fast detection of I- over S2-
Huang, Ximing,Lu, Zhengliang,Wang, Zhuo,Fan, Chunhua,Fan, Wenlong,Shi, Xiaomin,Zhang, Haitao,Pei, Meishan
, p. 33 - 40 (2016)
A novel bipyridine-functionalized turn-on fluorescent chemosensor was successfully synthesized and fully characterized by 1H NMR, 13C NMR and MS, UV-vis and fluorescence spectroscopies. The sensor specifically binds to Hg2+ over other competing ions with a significant fluorescence enhancement as well as a visual colour change under physiological conditions. The detection limit of Hg2+ was as low as 32 nM, confirming very high sensitivity toward Hg2+. Moreover, the fluorescence intensity and colour change of the sensor-Hg2+ was quenched by I- or S2- and was proportional to their concentrations with a detection limit of 0.37 μM and 0.43 μM, respectively. The reaction of I- grabbing Hg2+ from the sensor-Hg2+ finished in 10 s due to a stronger binding force, much faster than that of S2-, which allowed fast detection of I- over S2- even in a competent environment. In addition, the sensor was successfully used for the highly sensitive detection of Hg2+ in living cells.
New series of ruthenium(II) and osmium(II) complexes showing solid-state phosphorescence in far-visible and near-infrared
Chen, Jing-Lin,Chi, Yun,Chen, Kellen,Cheng, Yi-Ming,Chung, Min-Wen,Yu, Ya-Chien,Lee, Gene-Hsiang,Chou, Pi-Tai,Shu, Ching-Fong
, p. 823 - 832 (2010)
A new Ruii complex, [Ru(fpbpymH)2]Cl2 (1), in which fpbpymH = [5-(trifluoromethyl)pyrazol-3-yl](2,2'-bipyrid-6-yl)methane, was prepared by the treatment of [Ru(DMSO)4Cl2] with 2 equiv of the terdentate chelate fpbpymH in refluxing ethanol. A single-crystal X-ray diffraction study of 1 revealed a distorted octahedral Ruii framework, showing strong N-H- ... Cl hydrogen bonding between the fpbpymH ligand and Cl anions. In the presence of Na2CO3, the methylene linkers of chelates in 1 underwent stepwise oxygenation, forming the charge-neutral complexes [Ru(fpbpym)(fpbpyk)] (2) and [Ru(fpbpyk)2] (3) [fpbpykH = [5-(trtfluoromethyl)pyrazol-3-yG(2,2'-bipyrid-6-yl) ketone] in sequence. The respective charge-neutral Osii complex [Os(fpbpyk)2] (4) was also isolated by the treatment of OsCl3 -3H2O with 2 equiv of the terdentate chelate fpbpymH. Electrochemical analysis indicated that the introduction of the electron-withdrawing ketone group in 2-4 increased the metal-based oxidation potential in sequence. For the photophysical properties, complexes 1-4 are essentially nonluminescent in solution (e.g., CH 2Cl2 or MeOH) at room temperature, but all exhibit 600-1100 nm phosphorescence with moderate intensity for the powdery, solid sample at room temperature. The trend in terms of the emission peak wavelength of 1 (666 nm) 3 (795 nm) 2 (810 nm) 4 (994 nm) among titled complexes is in agreement with the corresponding onset of absorption spectra as well as the time-dependent density functional theory calculation of 1 3 2 4.
Secondary Coordination Effect on Monobipyridyl Ru(II) Catalysts in Photochemical CO2Reduction: Effective Proton Shuttle of Pendant Br?nsted Acid/Base Sites (OH and N(CH3)2) and Its Mechanistic Investigation
Back, Changhyun,Seo, Yunjeong,Choi, Sunghan,Choe, Min Su,Lee, Daehan,Baeg, Jin-Ook,Son, Ho-Jin,Kang, Sang Ook
, p. 14151 - 14164 (2021/09/20)
While the incorporation of pendant Br?nsted acid/base sites in the secondary coordination sphere is a promising and effective strategy to increase the catalytic performance and product selectivity in organometallic catalysis for CO2reduction, the control of product selectivity still faces a great challenge. Herein, we report two newtrans(Cl)-[Ru(6-X-bpy)(CO)2Cl2] complexes functionalized with a saturated ethylene-linked functional group (bpy = 2,2′-bipyridine; X = ?(CH2)2-OH or ?(CH2)2-N(CH3)2) at theortho(6)-position of bpy ligand, which are named Ru-bpyOHand Ru-bpydiMeN, respectively. In the series of photolysis experiments, compared to nontethered case, the asymmetric attachment of tethering ligand to the bpy ligand led to less efficient but more selective formate production with inactivation of CO2-to-CO conversion route during photoreaction. From a series ofin situFTIR analyses, it was found that the Ru-formate intermediates are stabilized by a highly probable hydrogen bonding between pendent proton donors (?diMeN+H or ?OH) and the oxygen atom of metal-bound formate (RuI-OCHO···H-E-(CH2)2-,E= O or diMeN+). Under such conformation, the liberation of formate from the stabilized RuI-formate becomes less efficient compared to the nontethered case, consequently lowering the CO2-to-formate conversion activities during photoreaction. At the same time, such stabilization of Ru-formate species prevents the dehydration reaction route (η1-OCHO → η1-COOH on Ru metal) which leads toward the generation of Ru-CO species (key intermediate for CO production), eventually leading to the reduction of CO2-to-CO conversion activity.
Engineering Second Sphere Interactions in a Host-Guest Multicomponent Catalyst System for the Hydrogenation of Carbon Dioxide to Methanol
Rayder, Thomas M.,Bensalah, Adam T.,Li, Banruo,Byers, Jeffery A.,Tsung, Chia-Kuang
supporting information, p. 1630 - 1640 (2021/02/05)
Many enzymes utilize interactions extending beyond the primary coordination sphere to enhance catalyst activity and/or selectivity. Such interactions could improve the efficacy of synthetic catalyst systems, but the supramolecular assemblies employed by biology to incorporate second sphere interactions are challenging to replicate in synthetic catalysts. Herein, a strategy is reported for efficiently manipulating outer-sphere influence on catalyst reactivity by modulating host-guest interactions between a noncovalently encapsulated transition-metal-based catalyst guest and a metal-organic framework (MOF) host. This composite consists of a ruthenium PNP pincer complex encapsulated in the MOF UiO-66 that is used in tandem with the zirconium oxide nodes of UiO-66 and a ruthenium PNN pincer complex to hydrogenate carbon dioxide to methanol. Due to the method used to incorporate the complexes in UiO-66, structure-activity relationships could be efficiently determined using a variety of functionalized UiO-66-X hosts. These investigations uncovered the beneficial effects of the ammonium functional group (i.e., UiO-66-NH3+). Mechanistic experiments revealed that the ammonium functionality improved efficiency in the hydrogenation of carbon dioxide to formic acid, the first step in the cascade. Isotope effects and structure-activity relationships suggested that the primary role of the ammonium functionality is to serve as a general Br?nsted acid. Importantly, the cooperative influence from the host was effective only with the functional group in close proximity to the encapsulated catalyst. Reactions carried out in the presence of molecular sieves to remove water highlighted the beneficial effects of the ammonium functional group in UiO-66-NH3+ and resulted in a 4-fold increase in activity. As a result of the modular nature of the catalyst system, the highest reported turnover number (TON) (19 ?000) and turnover frequency (TOF) (9100 h-1) for the hydrogenation of carbon dioxide to methanol are obtained. Moreover, the reaction was readily recyclable, leading to a cumulative TON of 100 ?000 after 10 reaction cycles.
Mechanistic Insights Into Iron(II) Bis(pyridyl)amine-Bipyridine Skeleton for Selective CO2 Photoreduction
Chen, Jia-Yi,Li, Xu-Bing,Liao, Rong-Zhen,Meng, Shu-Lin,Tung, Chen-Ho,Wang, Hai-Xu,Wang, Xu-Zhe,Wang, Yang,Wu, Li-Zhu,Zhou, Shuai
supporting information, p. 26072 - 26079 (2021/11/12)
A bis(pyridyl)amine-bipyridine-iron(II) framework (Fe(BPAbipy)) of complexes 1–3 is reported to shed light on the multistep nature of CO2 reduction. Herein, photocatalytic conversion of CO2 to CO even at low CO2 concentration (1 %), together with detailed mechanistic study and DFT calculations, reveal that 1 first undergoes two sequential one-electron transfer affording an intermediate with electron density on both Fe and ligand for CO2 binding over proton. The following 2 H+-assisted Fe-CO formation is rate-determining for selective CO2-to-CO reduction. A pendant, proton-shuttling α-OH group (2) initiates PCET for predominant H2 evolution, while an α-OMe group (3) cancels the selectivity control for either CO or H2. The near-unity selectivity of 1 and 2 enables self-sorting syngas production at flexible CO/H2 ratios. The unprecedented results from one kind of molecular catalyst skeleton encourage insight into the beauty of advanced multi-electron and multi-proton transfer processes for robust CO2RR by photocatalysis.
A Systematic Study of the Effects of Complex Structure on Aryl Iodide Oxidative Addition at Bipyridyl-Ligated Gold(I) Centers
Bower, John F.,Cadge, Jamie A.,Russell, Christopher A.
supporting information, p. 24976 - 24983 (2021/10/20)
A combined theoretical and experimental approach has been used to study the unusual mechanism of oxidative addition of aryl iodides to [bipyAu(C2H4)]+ complexes. The modular nature of this system allowed a systematic assessment of the effects of complex structure. Computational comparisons between cationic gold and the isolobal (neutral) Pd0 and Pt0 complexes revealed similar mechanistic features, but with oxidative addition being significantly favored for the group 10 metals. Further differences between Au and Pd were seen in experimental studies: studying reaction rates as a function of electronic and steric properties showed that ligands bearing more electron-poor functionality increase the rate of oxidative addition; in a complementary way, electron-rich aryl iodides give faster rates. This divergence in mechanism compared to Pd suggests that Ar?X oxidative addition with Au can underpin a broad range of new or complementary transformations.
Rhodium(iii)-catalyzed switchable C-H acylmethylation and annulation of 2,2′-bipyridine derivatives with sulfoxonium ylides
Chen, Chen,Chen, Mengjia,Meng, Haifang,Wang, Yani,Yang, Fang,Zhu, Bolin
supporting information, p. 4268 - 4271 (2021/05/31)
A novel protocol for Rh(iii)-catalyzed switchable C-H acylmethylation and annulation of 2,2′-bipyridine derivatives with sulfoxonium ylides is reported. This protocol provides a facile approach to synthesize structurally diverse acylmethylated 2,2′-bipyridine derivatives and acyl pyrido[2,3-a]indolizines with a broad range of functional group tolerance.
Pincerlike manganese complex and preparation method thereof, related ligand and preparation method thereof, catalyst composition and application
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Paragraph 0159-0165, (2021/07/31)
The invention discloses a pincerlike manganese complex, a preparation method thereof, a ligand for preparation, a preparation method of the ligand, a catalyst composition taking the complex as an active component and application of the catalyst composition. According to the pincerlike manganese complex, a cycloalkyl ring is introduced into a ligand framework, and by regulating and controlling the cyclic tension, flexibility and steric hindrance of the cycloalkyl ring, the reactivity and stability of the manganese metal center can be effectively adjusted, and the catalytic activity and substrate applicability of a manganese metal system are remarkably improved. The catalyst composition taking the pincerlike manganese complex as an active component has the advantages of high catalyst activity, wide substrate application range, mild reaction conditions and the like in the process of preparing quinoline or pyridine derivatives by catalyzing dehydrogenation coupling reaction of o-amino aromatic alcohol or gamma-amino alcohol, ketone or secondary alcohol; and the synthesis advantages of low cost and stable performance are embodied, the operation is simple, and the yield is high.
Direct synthesis of ring-fused quinolines and pyridines catalyzed byNNHY-ligated manganese complexes (Y = NR2or SR)
Han, Mingyang,Lin, Qing,Liu, Qingbin,Liu, Song,Ma, Ning,Solan, Gregory A.,Sun, Wen-Hua,Wang, Zheng,Yan, Xiuli
, p. 8026 - 8036 (2021/12/27)
Four cationic manganese(i) complexes, [(fac-NNHN)Mn(CO)3]Br (Mn-1-Mn-3) and [(fac-NNHS)Mn(CO)3]Br (Mn-4) (whereNNHis a 5,6,7,8-tetrahydro-8-quinolinamine moiety), have been synthesized and evaluated as catalysts for the direct synthesis of quinolines and pyridines by the reaction of a γ-amino alcohol with a ketone or secondary alcohol;NNHS-ligatedMn-4proved the most effective of the four catalysts. The reactions proceeded well in the presence of catalyst loadings in the range 0.5-5.0 mol% and tolerated diverse functional groups such as alkyl, cycloalkyl, alkoxy, chloride and hetero-aryl. A mechanism involving acceptorless dehydrogenation coupling (ADC) has been proposed on the basis of DFT calculations and experimental evidence. Significantly, this manganese-based catalytic protocol provides a promising green and environmentally friendly route to a wide range of synthetically important substituted monocyclic, bicyclic as well as tricyclicN-heterocycles (including 50 quinoline and 26 pyridine examples) with isolated yields of up to 93%.
