18653-75-3Relevant academic research and scientific papers
Synthesis, crystal structure, Hirshfeld surface analysis, electronic structure through DFT study and fluorescence properties of a new anthracene based organic tecton
Pal, Nilasish,Singha, Debabrata,Jana, Atish Dipankar
, p. 102 - 111 (2017)
A new organic molecule 9,10-bis((2-(pyridin-2-yl)-1H-imidazol-1-yl)methyl)anthracene (APIM) has been synthesized. Crystal structure analysis of the molecular solid reveals that CH?π and π?π interactions are the molecular packing forces in the solid state. Thermal analysis of the molecular solid shows relatively higher decomposition temperature of the crystalline molecular solid that correlates well with the cooperative nature of CH?π and π?π interactions. Density Functional Theory (DFT) optimized structure of the molecule closely correlates with that found in the crystal. DFT optimizations also lead to the similar CH?π and π?π interaction motifs that are found within the crystal. Hirshfeld surface analysis provides detailed insight into the relative importance of various weak forces in the molecular packing. Study of the fluorescence behavior of the molecules shows quenching in the presence of metal ions.
Ruthenium(II)–Pyridylimidazole Complexes as Photoreductants and PCET Reagents
Pannwitz, Andrea,Prescimone, Alessandro,Wenger, Oliver S.
, p. 609 - 615 (2017)
Complexes of the type [Ru(bpy)2pyimH]2+[bpy = 2,2′-bipyridine; pyimH = 2-(2-pyridyl)imidazole] with various substituents on the bpy ligands can act as photoreductants. Their reducing power in the ground state and in the long-lived3MLCT excited state is increased significantly upon deprotonation, and they can undergo proton-coupled electron transfer (PCET) in the ground and excited state. PCET with both the proton and electron originating from a single donor resembles hydrogen atom transfer (HAT) and can be described thermodynamically by formal bond dissociation free energies (BDFEs). Whereas the class of complexes studied herein has long been known, their N–H BDFEs have not been determined even though this is important in view of assessing their reactivity. Our study demonstrates that the N–H BDFEs in the3MLCT excited states are between 34 and 52 kcal mol–1depending on the chemical substituents at the bpy spectator ligands. Specifically, we report on the electrochemistry and PCET thermochemistry of three heteroleptic complexes in 1:1 (v/v) CH3CN/H2O with CF3, tBu, and NMe2substituents on the bpy ligands.
Control of redox potential by deprotonation of coordinated 1H-imidazole in complexes of 2-(1H-imidazol-2-yl)pyridine
Stupka, Gilles,Gremaud, Ludovic,Williams, Alan F.
, p. 487 - 495 (2005)
Complexes [ML3]2+ of the bidentate ligand 2-(1H-imidazol-2-yl)pyridine were prepared with iron(II), cobalt(II), and ruthenium(II). The electronic spectra suggest the ligand to be a weaker σ-donor and π-acceptor than the closely related 2,2′-bipyridine. The complexes are readily deprotonated by addition of base, and the effect of the deprotonation is to lower the MIII/MII redox potential by roughly 900 mV. This is roughly 75% of the drop observed for related complexes of 2,6-di-1H-imidazol-2-ylpyridine, and suggests the effect to be largely coulombic in origin.
Synthesis, characterization and use of imidazole and methyl-pyrazole based pyridine ligands as extractants for nickel(II) and copper(II)
Pearce, Brendan H.,Ogutu, Hezron F.O.,Saban, Waheed,Luckay, Robert C.
, p. 57 - 67 (2019)
This work consists of the synthesis of seven pyridine based ligands, 2-(3-butyl-1H-pyrazol-5-yl)-pyridine (1), 2-[3-(tert-butyl)-1H-pyrazol-5-yl]-pyridine (2), 2-(3-octyl-1H-pyrazol-5-yl)-pyridine (3), 2-(1-octyl-1H-imidazol-2-yl)pyridine (4), 2-[(1H-pyrazol-1-yl)methyl]pyridine (5), 2-[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]pyridine (6) and 2-[(3-methyl-1H-pyrazol-1-yl)methyl]pyridine (7) which have been made before. We modified some routes and obtained improved yields in most cases. The ligands were fully characterised using 1H and 13C NMR, infrared (IR) spectroscopy, mass spectrometry (ms), elemental analysis (EA) and melting point where appropriate. We managed to grow single crystals of the 2-[(1H-pyrazol-1-yl)methyl]pyridine copper(II) perchlorate complex and solved the structure using single crystal X-ray diffraction. Coordination around the copper(II) centre is pseudo square planar, having two ligands coordinated to the metal ion. Indications are that the extraction stoichiometry using this ligand for copper(II) is also 2:1, L:M. This indicates how these ligands are capable of coordinating to metal ions. All the ligands were then used for the extraction of Ni(II) with and without a synergist, viz., sodium p-dodecylbenzenesulfonate (SDBS). The solvent extraction of only Ni(II) in the absence of synergist produced values from 3% to 15% and values between 69% and 79% with synergist. The competitive extraction of metal ions from a base metal ion mix (Co2+, Ni2+, Zn2+, Cu2+, Pb2+ and Cd2+) produced extraction values of 15%?87% extraction of different metal ions with synergist. Finally, time dependent extraction studies with Ni(II) showed that after 4 h equilibrium was established and in some cases even after 1 h equilibrium had been reached.
Magnetic and liquid crystalline property of long-alkyl chain appended iron (II) imidazole complexes
Karim, Mohammad Razaul,Takehira, Hiroshi,Rahman, Mohammed M.,Asiri, Abdullah M.,Amin,Ohtani, Ryo,Hayami, Shinya
, p. 42 - 47 (2016)
Fe[((py)im-C16)3](BF4)2 (1) and Fe[((py)imH)3](BF4)2 (2), the Iron(II) compounds with C16 long alkyl chain appended (py)imH and unmodified (py)imH [(py)imH = 2-(2-pyridyl)imidazole] have be
Divalent Transition Metal Complexes of 2-(Pyridin-2-yl)imidazole: Evolved Gas Analysis Predicting Model to Provide Characteristic Coordination
Risoluti,Gullifa,Fabiano,Iona,Zuccatosta,Wo,Materazzi
, p. 2915 - 2921 (2017)
Previously published studies on imidazole derivative ligands suggested two main characteristic complex structures that are independent on the central metal ion. By the thermally induced decomposition behaviors, two different systematic decomposition trends were proposed. In this work, one of these characteristic decomposition mechanisms was again found for precipitated 2-(pyridin-2-yl)imidazole complexes. The final goal of these serial studies is to provide, by experimental evidences, a prediction model of thermal stability and typical decomposition behavior by comparing the structural characteristics of precipitated complexes. 2-(Pyridin-2-yl)imidazole complexes with transition metal ions of the general formula M(PyIm)2(H2O)2 (where M = Cu, Fe, Ni, Pd, Pt, Zn) were synthesized, characterized, and studied by thermoanalytical techniques coupled to mass spectrometry, to suggest their decomposition mechanism by evolved gas analysis (EGA-MS). As experimentally demonstrated in previous works, these complexes can be precipitated with two methanol molecules in the structure. By differential scanning calorimetry it was shown that methanol molecules can be replaced by water molecules under controlled conditions.
Modulation of photophysical properties of copper(I) complexes containing pyridyl-imidazole (PyIm) ligands functionalized by naphthyl, phenanthryl, and anthryl groups
Wang, Jinglan,Chai, Chaoyang,Xu, Shengxian,Zhao, Feng,Xia, Hongying,Wang, Yibo
, p. 237 - 244 (2019)
A series of Cu(I) pyridyl-imidazole (PyIm) complexes with different aryl groups (Ar = naphthalene (P2), phenanthrene (P3), and anthracene (P4)) attached on the pyridyl ring are synthesized and characterized. The influence of these organic chromophore groups on the photophysical properties of the resulting complexes is investigated. Complexes P2–P4 show stronger light harvesting efficiencies in the visible region compared with the parent complex P1. The emitting state of complex P1 originates from the 3MLCT state with some 3LLCT character, while complexes P2 and P3 predominantly exhibit the 3LLCT character. For complex P4, the triplet emitting state is dominated by the 3(π → π) state localized on the anthryl moiety, together with a lesser contribution form the 3LLCT state. These changes in the photophysical properties were rationalized by DFT and TDDFT methods.
Lowering water oxidation overpotentials using the ionisable imidazole of copper(2-(2′-pyridyl)imidazole)
Stott, Leea A.,Prosser, Kathleen E.,Berdichevsky, Ellan K.,Walsby, Charles J.,Warren, Jeffrey J.
, p. 651 - 654 (2017)
Rapid and low overpotential oxidation of water to dioxygen remains a key hurdle for storage of solar energy. Here, we address this issue by demonstrating that deprotonation of 2-(2′-pyridyl)-imidazole (pimH)-ligated copper complexes promotes water oxidation at low overpotential and low catalyst loading. This improves upon other work on homogeneous copper-based water oxidation catalysts, which are highly active, but limited by high overpotentials. EPR and UV-vis spectroscopic evaluation of catalyst speciation shows that at pH ≥ 12 coordinated pimH is deprotonated and a bis(hydroxide) Cu2+ active catalyst forms. Rapid electrochemical water oxidation (35 s-1, 0.85 V onset potential) was observed with 150 μM catalyst. These results demonstrate that catalytic water oxidation potentials can be shifted by hundreds of mV in homogeneous metal catalysts bearing an ionisable imidazole ligand.
Synthesis and characterization of novel fluorescent BOPIM dyes with large Stokes shift
Mao, Miaofu,Xiao, Shuzhang,Yi, Tao,Zou, Kun
, p. 612 - 616 (2011)
A novel BOPIM (boron 2-(2-pyridyl)imidazole complex) dye 1 was facilely synthesized by treatment of previously reported 2-(2′-pyridyl)imidazole with BF3·Et2O under basic condition. The bromination of BOPIM dye 1 by NBS gives an unexpected product 2-(2′-pyridyl)-4,5-dibromoimidazole (L2) with no BF2 group. The desired brominated boron complex 2 was obtained by treating L2 with BF 3·Et2O. The photophysical properties of these two compounds are thoroughly studied in various solvents. Compound 1 formed aggregates in non-polar solvents, inducing abnormal emission in long-wavelength region. Both 1 and 2 show moderate fluorescent intensity and comparatively large Stokes shift, especially for compound 2 (fluorescent quantum yield is more than 0.30, and Stokes shift is over 70 nm in all adopted solvents) due to its p, π-conjugated effect, which makes BOPIM a valuable building block for synthesis of multi-functional materials.
Low-melting cationic 3d-transition metal complexes of azole-based ligands
Huxel, Timo,Skaisgirski, Michael,Klingele, Julia
, p. 28 - 36 (2015)
Ligands N-methylimidazole (MIm) and N-ethylimidazole (EIm) were used for the preparation of [FeII(L)6](NTf2)2·0.5EtOH·0.5H2O. With Tfus = 83°C, the EIm complex was characterised as paramagn
