16280-66-3Relevant academic research and scientific papers
Structural, spectral and theoretical aspects in the coordination of a triazine-based ligand toward lead(II) with a holodirected environment
Marandi, Farzin,Moeini, Keyvan,Mostafazadeh, Bahman,Krautscheid, Harald
, p. 146 - 154 (2017)
Four complexes, [Cl(PPTA)2Pb(μ-Cl)2Pb(PPTA)2Cl] (1), [Br(PPTA)2Pb(μ-Br)2Pb(PPTA)2Br] (2), [I(PPTA)2Pb(μ-I)2Pb(PPTA)2I] (3) and [(PPTA)2Pb(NO3)2] (4), of 5-phenyl-3-(pyridin-2-yl)-1,2,4-triazine (PPTA) were prepared and identified by elemental analysis, FT-IR, 1H NMR spectroscopy and single-crystal X-ray diffraction. All the coordination modes of the 3-(pyridin-2-yl)-1,2,4-triazine-based ligands were studied by CSD software for predicting the behavior of the PPTA ligand in the reaction with metal ions. In the crystal structure of 1, the lead atom has a PbN4Cl3 environment with a distorted capped octahedral geometry. Complexes 2 and 3 are also dinuclear and isostructural with 1. The lead atom in the crystal structure of complex 4 has a coordination number of eight and a distorted cube geometry. The metal atom coordination spheres in all four structures tend to be holodirected with a decreasing deviation in the series 1–3. The thermodynamic stability of the isolated complexes and their charge distribution patterns were studied by DFT and NBO analysis. Theoretical studies reveal that the thermodynamic stability for the optimized complex 1 is more stable than those of the isostructural complexes 2 and 3.
Synthesis of 1,2,4-triazine derivatives via [4 + 2] domino annulation reactions in one pot
Tang, Dong,Wang, Jing,Wu, Ping,Guo, Xin,Li, Ji-Hui,Yang, Sen,Chen, Bao-Hua
, p. 12514 - 12518 (2016)
Simple and efficient [4 + 2] domino annulation reactions have been developed for the synthesis of 1,2,4-triazine derivatives. The strategies exhibit high performance with moderate to high yields, using easily available materials including ketones, aldehyd
Tandem oxidation processes for the regioselective preparation of 5-substituted and 6-substituted 1,2,4-triazines
Laphookhieo, Surat,Jones, Stuart,Raw, Steven A.,Sainz, Yolanda Fernández,Taylor, Richard J.K.
, p. 3865 - 3870 (2006)
α-Hydroxyketones undergo MnO2-mediated oxidation, followed by in situ trapping with 2-pyridylamidrazone, to give 3-pyridyl-5-substituted 1,2,4-triazines in a one-pot procedure, which avoids the need to isolate the reactive α-ketoaldehyde interm
Synthesis of Azaphosphinines by Directed Inverse-Electron-Demand Hetero-Diels–Alder Reactions with Na(OCP)
Hansmann, Max M.
, p. 11573 - 11577 (2018)
Herein, a straightforward synthetic approach towards azaphosphinines is reported. The synthesis of 1,3- and 1,4-aza-λ3-phosphinines as well as 1,2,4-diaza-λ3-phosphinines by inverse-electron-demand hetero-Diels–Alder reactions of sod
Palladium(II)complexes of ambidentate and potentially cyclometalating 5-aryl-3-(2′-pyridyl)-1,2,4-triazine ligands
Zvirzdinaite, Maryte,Garbe, Simon,Arefyeva, Natalia,Krause, Maren,Von Der Stück, René,Klein, Axel
, p. 2011 - 2022 (2017/12/06)
The 5-aryl-3-(2′-pyridiyl)-1,2,4-triazine ligands under study [5-phenyl-(PyTZPh)L1 5-(3-methoxyphenyl)-(PyTZ3Me-OPh)L2 5-(4-methoxyphenyl)-(PyTZ4MeOPh)L3 5-(4-trifluoromethylphenyl)-(PyTZ4CF3Ph)L4 5-(4-fluorophenyl)-(PyTZ4FPh)L5 and tris-3,5,6-(2′-pyridyl)-1,2,4-triazine (Py3TZ)L6] react with [(COD)PdCl2] (COD = 1,5-cyclooctadiento form complexes [(L1-6)PdCl2] with N,N bidentate binding ligands, also including the potentially N,N,N tridentate ligand L6. This was concluded from an in-depth NMR spectroscopic study of the new complexes and from comparison with Pd-terpy complexes [(R′ terpy)PdCl]Cl [R′terpy = 4′-R′-2,2′:6′,2′′-terpyridine R′ = H or SMe], showing definite tridentate N,N,N coordination, and with the Pd-bpy complexes [(bpy)Pd(Mes)Cl] and [(bpy)PdCl2], show-ing definite bidentate N,N binding. The new ligands and complexes were fully characterised by multinuclear NMR spectroscopy, IR spectroscopy and mass spectrometry. No evidence for the parent triazine complexes is observed in EI-MS instead, cyclometalated complexes (HCl eliminatiowere detected in all cases. TDA/TG experiments support this assumption. Attempts to prepare the cyclometalated derivatives as substances failed, in line with the unfavourable binding mode. Detailed electrochemical measurements reveal ligand-centred reductions at very moderate potentials, in line with UV/Vis absorption spectroscopy and DFT calculations, revealing very low-lying triazine-centred LUMOs. Results from cyclic voltammetry also support the composition of [(Py3TZ)PdCl2].
Useful preparation of 6-phenyl-2,2′-bipyridine ligands bearing di-n-butylaminophenyl or gallate derivatives substituted in the 3- or 4-positions
Diring, Stéphane,Retailleau, Pascal,Ziessel, Raymond
, p. 3027 - 3031 (2008/03/12)
A simple protocol for the efficient preparation of substituted 6-phenyl-2,2′-bipyridine derivatives is described. A reverse type of Diels-Alder reaction between a 6-phenyl-2-pyridyl-1,3,4-triazine and 4-N,N-di-n-butylaminophenyl- or gallate-ethynyl derivatives at high temperature provide a mixture of two products easily separable by column chromatography. A variety of ligands suitable for the synthesis of cyclometalated platinum complexes have been produced. Additional substitution of the Pt-Cl by various donor-acceptor ethynyl fragments is feasible by mean of copper(I) catalysis. Georg Thieme Verlag Stuttgart.
Synthesis of 6-phenyl-2,2′-bipyridine ligands bearing polyaromatic substituents
Diring, Stéphane,Retailleau, Pascal,Ziessel, Raymond
, p. 8069 - 8073 (2008/03/14)
A simple protocol for the efficient preparation of substituted 6-phenyl-2,2′-bipyridine derivatives is described. An inverse Diels-Alder reaction between a 3-phenyl-5-pyridyl-1,2,4-triazine and an electron-rich ethynyl species at high temperature provides a mixture of two products easily separable by column chromatography. The most encumbered isomer is favoured, likely due to favourable π-π stacking interactions in the transition state. A variety of those ligands suitable for the synthesis of cyclo-metallated complexes have been produced.
A rational protocol for the synthesis of arylated bipyridine ligands via a cycloaddition pathway
Diring, Stephane,Retailleau, Pascal,Ziessel, Raymond
, p. 10181 - 10193 (2008/04/12)
(Chemical Equation Presented) A generic design principle for the preparation of a variety of substituted phenyl-polypyridine ligands is described. These ligands are readily prepared by a regioselective [4+2] cycloaddition between electron-deficient dienes, such as 2,6-disubstituted-1,3, 4-triazines, and ethynyl-arenes or ethynyl-alkanes. Exceptional reactivity is found with electron-rich dienophiles bearing ethynylgallate or ethynylphenyldibutylamino groups. Two regioisomers are formed, the meta being preferred due to favorable π-π interactions in the transition state, while the para isomers are formed in low yields in most cases. The use of tert-butylacetylene or N,N-dimethylamino-2-propyne, however, drives the reaction exclusively to the para isomer. Di-N,N-dibutylaminophenyl or isoquinoline ligands can also be produced in a single step by reverse Diels-Alder reactions. Cross-coupling reactions of iodo-substituted ligands or their platinum(II) complexes under Pd(0) catalysis gives branched ligands and complexes bearing paraffin chains, electron-donor or electron-acceptor groups. The use of a chloro-Pt(II) complex of an iodo-functionalized ligand allows both halogens to be replaced by ethynyl groups by using different catalysts. This methodology readily accommodates various functional groups and has been successfully extended to systems containing a variety of donor/acceptor frameworks. All ligands strongly absorb in the near-UV and luminesce in solution at rt with quantum yields ranging from 0 to 66%. Excited state lifetimes are in the nanosecond range and the solvent effects are in keeping with singlet excited states mixed with charge-transfer character. As deduced from spectroscopic and electrochemical studies, the di-n-butylamino derivatives are strong reductants in the excited state.
