149810-35-5Relevant academic research and scientific papers
Ruthenium-cymene containing pyridine-derived aldiimine ligands: Synthesis, characterization and application in the transfer hydrogenation of aryl ketones and kinetics studies
Ramos, Thiago S.,Luz, Diego M.,Nascimento, Rebecca D.,Silva, Andressa K.,Li?o, Luciano M.,Miranda, Victor M.,Deflon, Victor M.,de Araujo, Márcio P.,Ueno, Leonardo T.,Machado, Francisco B.C.,Dinelli, Luís R.,Bogado, André L.
, p. 51 - 65 (2019)
Five electron-rich N[sbnd]N′?pyridylimine ligands, which form five-membered chelate ring when coordinate to a metal center, have been synthesized by the easily accessible condensation between 2-pyridinecarboxyaldhehyde and the corresponding substituted an
Organoaluminum Compounds as Catalysts for Monohydroboration of Carbodiimides
Shen, Qiumiao,Ma, Xiaoli,Li, Wenling,Liu, Wenqing,Ding, Yi,Yang, Zhi,Roesky, Herbert W.
, p. 11918 - 11923 (2019)
The effective catalytic activity of organoaluminum compounds for the monohydroboration of carbodiimides has been demonstrated. Two aluminum complexes, 2 and 3, were synthesized and characterized. The efficient catalytic performances of four aluminum hydri
Siliciumverbindungen mit starken intramolekularen sterichen Wechselwirkungen. L. Reaktionen von Silylenen und Disilenen mit 2,2'-Bipyridyl, Pyridin-2-aldiminen und α-Ketoiminen: Cycloadditionen versus C-H-Insertion
Weidenbruch, Manfred,Piel, Harald,Lesch, Axel,Peters, Karl,Schnering, Hans Georg von
, p. 35 - 43 (1993)
Treatment of 2,2'-bipyridyl or its 4,4'-dimethyl derivative with the sterically encumbered silylenes t-Bu2Si: and Mes2Si: gives violet, very air-sensitive 2,2'-bipyridyl(N,N')silanes in which the heteroaromatic rings are converted into conjugated double-bond systems.Reaction of these silylenes with N-t-butylpyridine-2-aldimine proceeds also in a (4+1)-fashion to provide the N-t-butylpyridine-2-aldimine-(N,N')silanes 11 and 12.Subsequent addition of tetra-t-butyldisilene across the CC double bond of 12 in the 3,4-position gives the tricyclic compound 13.Replacement of the N-t-butyl by the sterically more crowded N-2,6-diisopropylphenyl group leads to an unprecedented intermolecular insertion of dimesitylsilylene into the CH bond of the acyclic CN group.The structure of the insertion product (N-2,6-diisopropylphenyl)-1,1-dimesityl-2-pyridine-2-yl-1-silaethane-2-imine (15) was confirmed by X-ray crystallography.Photolysis of hexa-t-butylcyclotrisilane in the presence of α-ketoimines bearing isopropyl or cyclohexyl groups at the nitrogen atom gives the corresponding silylene cycloaddition products to the N- and O-atoms.With the N-methyl derivative, however, the (4+2)-cycloaddition product 21 of tetra-t-butyldisilene to these atoms is isolated.The X-ray structure analysis of the 1-oxa-2,3-disila-4-aza-5-cyclohexane derivative 21 shows that the unsaturated six-membered ring has the half chair conformation, which minimizes the repulsive interactions betwen the bulky substituents and leads to a hardly stretched Si-Si bond length (237.9 pm).
Unsymmetrical N-Aryl-1-(pyridin-2-yl)methanimine Ligands in Organonickel(II) Complexes: More Than a Blend of 2,2′-Bipyridine and N,N-Diaryl-α-diimines?
Biewer, Christian,Hamacher, Claudia,Kaiser, Andre,Vogt, Nicolas,Sandleben, Aaron,Chin, Mason T.,Yu, Siqi,Vicic, David A.,Klein, Axel
, p. 12716 - 12727 (2016)
The new organonickel complexes [(R-PyMA)Ni(Mes)X] [R-PyMA = N-aryl-1-(pyridin-2-yl)methanimine; aryl = phenyl, 2,6-Me2-, 3,5-Me2-, 2,4,6-Me3-, 2,6-iPr2-, 3,5-(OMe)2-, 2-NO2-4-Me-, 4-NO2-, 2-CF3-, and 2-CF3-6-F-phenyl; Mes = 2,4,6-trimethylphenyl; X = F, Cl, Br, or I] were obtained as approximate 1/1 cis and trans isomeric mixtures or pure cis isomers depending on the PyMA ligand and X. The [(R-PyMA)Ni(Mes)X] complexes with X = Br or Cl were directly synthesized from the precursors trans-[(PPh3)2Ni(Mes)X], while [(PyMA)Ni(Mes)X] derivatives with X = F or I were obtained from [(PyMA)Ni(Mes)Br] through X exchange reactions. Although density functional theory (DFT) calculations show a preference for the sterically favored cis isomers, both isomers could be observed in many cases; in three cases, even single crystals for X-ray diffraction could be obtained for the trans isomers. Possible intermediates for the isomerization were investigated by DFT calculations. All complexes were studied by multiple spectroscopic means, electrochemistry, and spectroelectrochemistry (for the reduction processes). The long-wavelength metal-to-ligand charge-transfer (MLCT) absorptions vary markedly with the R substituent of the ligand and the cathodic electrochemical potentials to a far smaller degree. Both are almost invariable upon variation of X. All of this is in line with Ni-based and π?-based lowest unoccupied molecular orbitals (LUMOs). In line with the unsymmetric character of the NPy^Nmethanimine ligand, electrochemistry and MLCT transitions seem to not correspond to the same type of ? LUMO, making these PyMA ligands more interesting than the symmetric heteroaromatic polypyridine ligands such as 2,2′-bipyridine (bpy; NPy^NPy) and N,N-diaryl-substituted aliphatic α-diimines (Nmethanimine^Nmethanimine) such as the diaza-1,3-butadienes (DAB). First attempts to use these complexes in Negishi-type cross-coupling reactions were successful.
Synthesis and structural elucidation of (pyridyl)imine Fe(II) complexes and their applications as catalysts in transfer hydrogenation of ketones
Tsaulwayo, Nokwanda,Kumah, Robert T.,Ojwach, Stephen O.
supporting information, (2021/01/25)
Reactions of (pyridyl)imine ligands: 2,6-diisopropyl-N-[(pyridine-2-yl)methylene]aniline (L1), 2,6-diisopropyl-N-[(pyridine-2-yl)ethylidene]aniline (L2), 2,6-dimethyl-N-[(pyridine-2-yl)methylene]aniline (L3), 2,6-dimethyl-N-[(pyridine-2-yl)ethylidene]aniline (L4) and N-[(pyridine-2-yl)methylene]aniline (L5) with FeCl2 salt afforded the corresponding paramagnetic Fe(II) complexes [Fe(L1)2Cl][FeCl4] (Fe1), [Fe(L2)2Cl][FeCl4] (Fe2), [Fe(L3)2Cl][FeCl4] (Fe3), [Fe(L4)2Cl][FeCl4], (Fe4), [Fe(L5)2Cl2] (Fe5) in good yields. On the other hand, reactions of L1 with FeCl2 in the presence of NaPF6 afforded complex [Fe(L1)2Cl][PF6] (Fe6) in moderate yields. Molecular structures of complexes Fe1 and Fe2 reveal the formation of cationic species containing two N^N bidentate ligands and one chlorido co-ligand to give five-coordinate geometry with [FeCl4]? as counter-anion. On the other hand, complex Fe5, is an octahedral neutral species containing two bidentate L5 and two chlorido ligands. All the complexes (Fe1–Fe6) formed active catalysts in the transfer hydrogenation of ketones affording average yields of about 85%. The ligand architecture, reaction conditions and nature of substrate influenced the catalytic activities of the complexes. Mercury and subs-stoichiometric poisoning tests pointed to the existence of both Fe(0) nanoparticles and homogeneous Fe(II) species as the active intermediates.
Highly active iminopyridyl iron-based catalysts for the polymerization of isoprene
Hashmi, Obaid H.,Champouret, Yohan,Visseaux, Marc
, (2019/09/04)
A series of iminopyridyl-based ligands, 6-[(Ar)N=C(R)]-2-C6H5N [(Ar = 2,6-Me2-C6H3, R = Me (L1); Ar = 2,6-iPr2-C6H3, R = Me (L2); Ar = 2,6-Me2-C6H3, R = H (
Photochemical oxidation of water catalysed by cyclometalated Ir(iii) complexes bearing Schiff-base ligands
Dhiman, Rekha,Nagaraja
, p. 13662 - 13669 (2019/09/06)
Synthesis, characterization and photochemical water oxidation activity of three cyclometalated Ir(iii) complexes, [(η5-C5Me5)Ir(L1)Cl]PF6 (1), [(η5-C5Me5)Ir(L2)Cl]PF6
Steric demands in the formation of heteroleptic Cu(I) complexes with α-diimines and triphenylphosphine
Tseriotou, Eleni,Tzimopoulos, Dimitris,Hatzidimitriou, Antonis,Akrivos, Pericles
, p. 152 - 157 (2018/07/29)
The synthesis and the study of the molecular structure of a series of heteroleptic copper(I) compounds with triphenylphosphine and α-diimines presenting a varying degree of bulk at their chelating cite is reported. The most sterically crowded diimine acts as a monodentate ligand towards copper(I) promoting bridging of the halogen atom present in the metal coordination sphere and formation of a dimer. Evidence for this behavior is obtained from the electronic spectra and semiempirical quantum chemical calculations with MOPAC. Steric demands in all the studied compounds preclude coordination of silver(I) under similar reaction conditions.
Lysosome-Targeted Chemotherapeutics: Half-Sandwich Ruthenium(II) Complexes That Are Selectively Toxic to Cancer Cells
Tian, Zhenzhen,Li, Juanjuan,Zhang, Shumiao,Xu, Zhishan,Yang, Yuliang,Kong, Deliang,Zhang, Hairong,Ge, Xingxing,Zhang, Junming,Liu, Zhe
supporting information, p. 10498 - 10502 (2018/09/11)
Poor selectivity between cancer cells and normal cells is one of the major limitations of cancer chemotherapy. Lysosome-targeted ruthenium-based complexes target tumor cells selectively, only displaying rather weak cytotoxicity or inactivity toward normal cells. Confocal microscopy was employed for the first time to determine the cellular localization of the half-sandwich Ru complex.
Steric control in the metal-ligand electron transfer of iminopyridine-ytterbocene complexes
Trifonov, Alexander A.,Mahrova, Tatyana V.,Luconi, Lapo,Giambastiani, Giuliano,Lyubov, Dmitry M.,Cherkasov, Anton V.,Sorace, Lorenzo,Louyriac, Elisa,Maron, Laurent,Lyssenko, Konstantin A.
, p. 1566 - 1576 (2018/02/09)
A systematic study of reactions between Cp?2Yb(THF) (Cp? = η5-C5Me5, 1) and iminopyridine ligands (IPy = 2,6-iPr2C6H3NCH(C5H3N-R), R = H (2a), 6-C4H3O (2b), 6-C4H3S (2c), 6-C6H5 (2d)) featuring similar electron accepting properties but variable denticity and steric demand, has provided a new example of steric control on the redox chemistry of ytterbocenes. The reaction of the unsubstituted IPy 2a with 1, either in THF or toluene, gives rise to the paramagnetic species Cp?2YbIII(IPy)- (3a) as a result of a formal one-electron oxidation of the YbII ion along with IPy reduction to a radical-anionic state. The reactions of 1 with substituted iminopyridines 2b-d, bearing aryl or hetero-aryl dangling arms on the 6 position of the pyridine ring occur in a non-coordinating solvent (toluene) only and afford coordination compounds of a formally divalent ytterbium ion, coordinated by neutral IPy ligands Cp?2YbII(IPy)0 (3b-d). The X-ray diffraction studies revealed that 2a-c act as bidentate ligands; while the radical-anionic IPy in 3a chelates the YbIII ion with both nitrogens, neutral IPy ligands in 3b and 3c participate in the metal coordination sphere through the pyridine nitrogen and O or S atoms from the furan or thiophene moieties, respectively. Finally, in complex 3d the neutral IPy ligand formally adopts a monodentate coordination mode. However, an agostic interaction between the YbII ion and an ortho C-H bond of the phenyl ring has been detected. Imino-nitrogens in 3b-d are not involved in the metal coordination. Variable temperature magnetic measurements on 3a are consistent with a multiconfigurational ground state of the Yb ion and suggest that the largest contribution arises from the 4f13-radical configuration. For complexes 3b and 3c the data of magnetic measurements are indicative of a YbII-closed shell ligand electronic distribution. Complex 3d is characterized by a complex magnetic behavior which does not allow for an unambiguous estimation of its electronic structure. The results are rationalized using DFT and CSSCF calculations. Unlike diazabutadiene analogues, 3a does not undergo a solvent mediated metal-ligand electron transfer and remains paramagnetic in THF solution. On the other hand, complexes 3b-d readily react with THF to afford 1 and free IPy 2b-d.
