261903-04-2Relevant articles and documents
Dinuclear cobalt complexes with a redox active biphenyl bridging ligand [Co2(BP)(tqa)2](PF6)2(H4BP = 4,4′-bis(3-tert-butyl-1,2-catechol), tqa = tris(2-quinolylmethyl)amine): structure and magnetic properties
Kuroda-Sowa, Takayoshi,Maekawa, Masahiko,Mibu, Takuto,Okubo, Takashi,Suenaga, Yusaku,Sugimoto, Kunihisa
supporting information, p. 9833 - 9841 (2021/07/28)
The biscatechol, H4BP (4,4′-bis(3-tert-butyl-1,2-catechol)) that can directly connect two redox active catechol moieties was synthesized. Also, tris(2-pyridylmethyl)amine (tpa), bis(2-pyridylmethyl)(2-quinolylmethyl)amine (bpqa), (2-pyridylmethyl)bis(2-quinolyl methyl)amine (pbqa), and tris (2-quinolylmethyl)amine (tqa) were synthesized as terminal ligands of the tetracoordinated tripod. In total, five different dinuclear Co complexes were synthesized from H4BP with various terminal ligands as follows, [Co2(BP)(tpa)2](PF6)2(1), [Co2(BP)(tpa)2](PF6)3(2), [Co2(BP)(bpqa)2](PF6)2(3), [Co2(BP)(pbqa)2](PF6)2(4), and [Co2(BP)(tqa)2](PF6)2(5). After a one-electron oxidation reaction of complex (1), complex (2), was isolated as a mixed valence state lsCoIII-[SQ-Cat]-lsCoIII, with an absorption intensity of about 1370 nm (intervalence charge transfer (IVCT) bands) in CH3CN solution. In addition, an investigation of the magnetic properties of the dinuclear Co complex (3) with SQUID showed that theχMTvalue gradually increased as the temperature increased from 280 to 380 K. Studies in the solid and solution states using electronic spectra, cyclic voltammetry and SQUID for the above complexes provide clear evidence for three different charge distributions: complexes (1) and (3) are CoIII-[Cat-Cat]-CoIII, complex (2) is CoIII-[Sq-Cat]-CoIII, complexes (4) and (5) are CoII-[Sq-Sq]-CoII. Of the five cobalt dinuclear complexes, only complex (3) shows evidence of the temperature dependence of the charge distribution, displaying a thermally induced valence tautomeric transition from the lsCoIII-[Cat-Cat]-lsCoIIIto hsCoII-[Sq-Sq]-hsCoIIin both solid and solution states. However, this valence tautomeric step is incomplete at 380 K, with the?χMT?value of hsCoII-[Sq-Sq]-hsCoII. This suggests that the steric hindrance of the quinolyl rings around the Co ion produces a coordination atmosphere that is weaker than that observed with pyridyl rings, which facilitates a change in the CoIIIions to CoII
Synthesis and structure-activity relationship studies of hydrazide-hydrazones as inhibitors of laccase from trametes versicolor
Giurg, Miros?aw,Maniak, Halina,Matyja, Konrad,Talma, Micha?,Trusek, Anna
supporting information, (2020/03/23)
A series of hydrazide-hydrazones 1-3, the imine derivatives of hydrazides and aldehydes bearing benzene rings, were screened as inhibitors of laccase from Trametes versicolor. Laccase is a copper-containing enzyme which inhibition might prevent or reduce the activity of the plant pathogens that produce it in various biochemical processes. The kinetic and molecular modeling studies were performed and for selected compounds, the docking results were discussed. Seven 4-hydroxybenzhydrazide (4-HBAH) derivatives exhibited micromolar activity Ki = 24-674 μM with the predicted and desirable competitive type of inhibition. The structure-activity relationship (SAR) analysis revealed that a slim salicylic aldehyde framework had a pivotal role in stabilization of the molecules near the substrate docking site. Furthermore, the presence of phenyl and bulky tert-butyl substituents in position 3 in salicylic aldehyde fragment favored strong interaction with the substrate-binding pocket in laccase. Both 3- and 4-HBAH derivatives containing larger 3-tert-butyl-5-methyl- or 3,5-di-tert-butyl-2-hydroxy-benzylidene unit, did not bind to the active site of laccase and, interestingly, acted as non-competitive (Ki = 32.0 μM) or uncompetitive (Ki = 17.9 μM) inhibitors, respectively. From the easily available laccase inhibitors only sodium azide, harmful to environment and non-specific, was over 6 times more active than the above compounds.
Syntheses, structure and properties of dinuclear Co complexes with bis(catecholate) ligands – Effect of a quinoline ring in the terminal group
Suenaga, Yusaku,Mibu, Takuto,Okubo, Takashi,Maekawa, Masahiko,Kuroda-Sowa, Takayoshi
supporting information, p. 480 - 485 (2019/08/26)
Two types of biscatechol, namely H4L1 (5,5′-(buta-1,3-diyne-1,4-diyl)bis(3-t-butylcatechol)) and H4L2 (5,5′-(ethyne-1,2-diyl)bis(3-t-butylcatechol)) were synthesized. In these ligands, two redox active catechol moieties are connected by one or two triple bonds. Also, tpa (tris(2-pyridylmethyl) amine), bpqa (bis(2-pyridylmethyl)(2-quinolylmethyl)amine) and pbqa ((2-pyridylmethyl)bis(2-quinolylmethyl)amine) were synthesized as terminal ligands of the tetracoordinated tripod type. In total, six dinuclear Co complexes were synthesized from these biscatechol and terminal ligands as follows: [Co2(L1)(tpa)2](BF4)2 (1), [Co2(L1)(bpqa)2](PF6)2 (2), [Co2(L1)(pbqa)2](PF6)2 (3), [Co2(L2)(tpa)2](BF4)2 (4), [Co2(L2)(bpqa)2](PF6)2 (5), [Co2(L2)(pbqa)2](PF6)2 (6). Of the six dinuclear Co complexes, complex 6, which was isolated as a mixed valent state CoII(HS)-[SQ-Cat]-CoIII(LS) compound, showed an absorption intensity at around 703 nm (MLCT bands) that increased with increasing temperature in acetonitrile solution. In addition, an investigation of the magnetic properties of the complex 6 with SQUID showed that the χMT value gradually increased as the temperature increased from 150 to 380 K. This suggests that a transition from CoIII(LS) (S = 0) to CoII(HS) (S = 3/2) accompanies the temperature rise. This means the steric hindrance and electronic effect of the quinolyl groups around the Co ion produce a coordination atmosphere weaker than that of pyridyl groups, with the result that the CoIII ions easily convert to CoII ions.
Reaction of 2,8-bis(o -hydroxyaryl)quinolines with group 4 metal alkyls resulting in three distinct coordination modes of the tridentate ligand. X-ray structure of complexes and performance as precursors in ethylene polymerization catalysis
Nifant'ev, Ilya E.,Ivchenko, Pavel V.,Bagrov, Vladimir V.,Nagy, Sandor M.,Mihan, Shahram,Winslow, Linda N.,Churakov, Andrei V.
supporting information, p. 2685 - 2692 (2013/06/27)
A series of bis(o-hydroxyphenyl)quinolines have been prepared, starting from 2,8-dibromoquinoline. Reaction of these new ligand precursors with group 4 tetrabenzyl complexes MBn4 results in benzyl substitution of the azine fragment with the formation of amide complexes (M = Ti) or amine complexes with an N-H fragment coordinated to the metal (M = Zr, Hf). The third structural type - Zr complexes where the aromatic system of the precursor remains intact - can be prepared through the reaction of the bis(o-hydroxyphenyl)quinolones with 4 mol of methyllithium, followed by ZrCl4. The new complexes result in active polymerization catalysts when activated with MAO/borate cocatalysts on silica supports, resulting in polyethylene copolymers with very high molecular weights and multimodal MWDs.
Nitronyl nitroxide radicals as organic memory elements with both n- and p-type properties
Lee, Junghyun,Lee, Eunkyo,Kim, Sangkwan,Bang, Gyeong Sook,Shultz, David A.,Schmidt, Robert D.,Forbes, Malcolm D. E.,Lee, Hyoyoung
supporting information; experimental part, p. 4414 - 4418 (2011/06/22)
Can't fight the SEEPR: Simultaneous electrochemical electron paramagnetic resonance reveals that a molecule containing the nitronyl nitroxide (NN) radical (structure and red layer) is redox-active, with switchability between oxidized and reduced states. An organic NN radical device utilizes the dual p- and n-type properties in a memory device. Copyright
Stereoselective ring-opening polymerization of a racemic lactide by using achiral salen- and homosalen-aluminum complexes
Nomura, Nobuyoshi,Ishii, Ryohei,Yamamoto, Yoshihiko,Kondo, Tadao
, p. 4433 - 4451 (2008/02/09)
Highly isotactic polylactide or poly(lactic acid) is synthesized in a ring-opening polymerization (ROP) of racemic lactide with achiral salen- and homosalen-aluminum complexes (salenH2 = N,N′-bis(salicylidene) ethylene-1,2-diamine; homosalenH2 = N,N′-bis(salicylidene) trimethylene-1,3-diamine). A systematic exploration of ligands demonstrates the importance of the steric influence of the Schiff base moiety on the degree of isotacticity and the backbone for high activity. The complexes prepared in situ are pure enough to apply to the polymerizations without purification. The crystal structures of the key complexes are elucidated by X-ray diffraction, which confirms that they are chiral. However. analysis of the 1H and 13C NMR spec tra unambiguously demonstrates that their conformations are so flexible that the chiral environment of the complexes cannot be maintained in solution at 25°C and that the complexes are achiral under the polymerization conditions. The flexibility of the back-bone in the propagation steps is also documented. Hence, the isotacticity of the polymer occurs due to a chain-end control mechanism. The highest reactivity in the present system is obtained with the homosalen ligand with 2.2-dimethyl substituents in the backbone (ArCH=NCH2CMe2CH2N=CHAr), whereas tBuMe2Si substituents at the 3-positions of the salicylidene moieties lead to the highest selectivity (Pmeso,= 0.98; T m = 210°C). The ratio of the rate constants in the ROPs of racemic lactide and L-lactide is found to correlate with the stereoselectivity in the present system. The complex can be utilized in bulk polymerization, which is the most attractive in industry, although with some loss of stereoselectivity at high temperature, and the afforded polymer shows a higher melting temperature (Pmeso = 0.92, Tm up to 189°C) than that of homochiral poly(L-lactide) (Tm = 162-180°C). The "livingness" of the bulk polymerization at 130°C is maintained even at a high conversion (97-98%) and for an extended polymerization time (1-2 h).
Chiral zirconium catalysts using multidentate BINOL derivatives for catalytic enantioselective Mannich-type reactions; ligand optimization and approaches to elucidation of the catalyst structure
Ihori, Yoichi,Yamashita, Yasuhiro,Ishitani, Haruro,Kobayashi, Shu
, p. 15528 - 15535 (2007/10/03)
Catalytic enantioselective Mannich-type reactions of silicon enolates with aldimines were investigated using chiral zirconium catalysts prepared from Zr(OtBu)4, N-methylimidazole, and newly designed multidentate BINOL derivatives. Th
POLYMERISATION CATALYSTS
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Page 17, (2010/02/08)
A transition metal complex having the following Formula (A): wherein the monovalent groups RI and R2 are -Ra,-ORb, -NRcRd, and -NHRe: the monovalent groups Ra, R
2-IMINOPYRROLIDINE DERIVATES
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Page 160, (2008/06/13)
A 2-iminopyrrolidine derivative represented by the formula: {wherein ring B represents a benzene ring, pyridine ring, etc.; R101 - R103 represent hydrogen, halogen, C1-6 alkyl, etc.; R5 represents hydrogen, C1-6 alkyl, C1-6 alkoxy-C1-6 alkyl, etc.; R6 represents hydrogen, C1-6 alkyl, C1-6 alkyloxycarbonyl, etc.; Y1 represents a single bond, -CH2-, etc.; Y2 represents a single bond, -CO-, etc.; and Ar represents hydrogen, a group represented by the formula: [wherein R10-R14 represent hydrogen, C1-6 alkyl, hydroxyl, C1-6 alkoxy, etc.; and R11 and R12 or R12 and R13 may bond together to form a 5- to 8-membered heterocyclic ring], etc.}, or a salt thereof.
