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1.

001-es BibID:BIBFORM078704
Első szerző:Buglyó Péter (vegyész)
Cím:Tuning the redox potentials of ternary cobalt(III) complexes containing various hydroxamates / Buglyó Péter, Kacsir István, Kozsup Máté, Nagy Imre, Nagy Sándor, Bényei Attila Csaba, Kováts Éva, Farkas Etelka
Dátum:2018
ISSN:0020-1693
Megjegyzések:Sixteen cobalt(III) complexes incorporating one of the investigated 4N donor tripodal amines in the presence or absence of differently substituted hydroxamates have been synthesized and the effect of the nature of the N-donor, size of the chelates formed and the effect of the type of the substituent(s) at the hydroxamate moiety on the redox properties of the complexes have been studied. The crystal and molecular structures of the new complexes, [Co(unspenp)(H2O)Cl]Cl2.H2O (4), [Co(tren)(phebha)](ClO4)2 (11), [Co(tpa)(bha)](ClO4)2?C2H5OH?H2O (15) and [Co(tpa)(phebha)](ClO4)2 (16) have also been determined by single crystal X-ray diffraction method. Cyclic voltammetric (CV) results indicated the irreversible reduction of Co(III) in all the investigated complexes. Out of the four studied tripodal amines, abap was found to decrease the Co(III/II) reduction potential far below the region of bioreductants. Decreasing of two of the chains by one CH2 in tren compared to abap resulted in less negative reduction potential of the corresponding complex. Further positive shift was observed by introducing two (uns-penp), and especially three (tpa) ?-back-bonding pyridyl rings into the chains of tetramines. In agreement with literature results, the 3+ oxidation state of the central cobalt ion was found to be extremely stabilized in the ternary complexes containing the doubly deprotonated benzohydroximate, but the metal ion is significantly more reducible in the ternary complexes with mono-deprotonated benzohydroxamate/derivative ligands. Measurable effect was not found on the redox potential via introduction of chloro or nitro substituents in para position into the phenyl moiety of bha? (Cl-bha? and NO2-bha? ). Significant positive shift (ca. 200 mV) was obtained, however, when RN = H was replaced by a phenyl ring in phebha? therefore complexes with this latter ligand can be likely candidates for the in vitro releasing of hydroxamates with proven biological activity.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Inorganica Chimica Acta. - 472 (2018), p. 234-242. -
További szerzők:Kacsir István (1994-) (vegyész) Kozsup Máté (1992-) (Okleveles vegyész) Nagy Imre (1992-) (vegyész analitikus) Nagy Sándor (1993-) (vegyész) Bényei Attila (1962-) (vegyész) Kováts Éva (1977-) (vegyész) Farkas Etelka (1948-) (vegyész)
Pályázati támogatás:GINOP-2.3.2-15-2016-00008
GINOP
OTKA-112317
OTKA
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DOI
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2.

001-es BibID:BIBFORM107565
035-os BibID:(Cikkazonosító)121153 (WoS)000849920300005 (Scopus)85136453241
Első szerző:Császár Zsófia (vegyész)
Cím:Hydrogen bond-directed coordination of phosphine-amino-alcohol (P,N,OH) ligands: Stereochemical considerations and catalytic studies / Zsófia Császár, Mária Guóth, Evelin Farsang, Attila C. Bényei, József Bakos, Gergely Farkas
Dátum:2022
ISSN:0020-1693 1873-3255
Megjegyzések:Novel phosphine-aminoalcohol type chiral ligands of the chemical formula Ph2PCH(CH3)CH2CH(CH3)NHCH(R)CH2OH (1a: (R, R)-(S), R = CH3 , 1b: (S, S)-(S), R = CH3 , 1c: (S, S), R = H) have been synthesized in two simple steps using cyclic sulfates. The coordination behavior of 1a-c having stereochemically labile nitrogen donor to square planar Pd(II) center was investigated by X-ray crystallography, 1D and 2D NMR methods and by DFT calculations. In the solid state of complex [Pd(1a)Cl-2] an intramolecular hydrogen bond could be observed between the OH-moiety and one of the Cl co-ligands, while intermolecular hydrogen bonds were detected in the case of [Pd(1b)Cl-2] between the same functionalities. In the dichloromethane solution of the complexes the hydrogen bond was identified as a crucial factor in determining ring conformation and nitrogen configuration. Ligand 1a coordinated stereoselectively to the metal in [Pd(1a)Cl-2] leading to a complex having a single conformationally rigid six-membered chelate and a configurationally fixed N-donor. In contrast, coordination of ligands 1b-c resulted in the formation of a mixture of isomers with different chelate conformation and nitrogen configuration. The ligands were utilized in Pd-catalyzed asymmetric allylic alkylation where high enantioselectivities (ees up to 96 %) and activities could be obtained.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Inorganica Chimica Acta. - 543 (2022), p. 1-8. -
További szerzők:Guóth Mária Farsang Evelin Bényei Attila (1962-) (vegyész) Bakos József (vegyész) Farkas Gergely
Pályázati támogatás:K128074
Egyéb
TKP2021-NKTA-21
Egyéb
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3.

001-es BibID:BIBFORM084876
Első szerző:Gulyás Henrik
Cím:Catalytic properties of water-soluble rhodium and iridium complexes : the influence of the ligand structure / Henrik Gulyás, Attila C. Bényei, József Bakos
Dátum:2004
ISSN:0020-1693
Megjegyzések:Rhodium and iridium complexes of trisulfonated triarylphosphanes, TPPTS (tris(3-sulfonatophenyl)phosphane), T(p-A)PTS (tris(3-sulfonato-4-methoxyphenyl)phosphane), T(2,4-X)TS (tris(2,4-dimethyl-5-sulfonatophenyl)phosphane), have been tested in biphasic hydrogenation of aldehydes. T(2,4-X)TS could not stabilize the rhodium complex under the applied conditions. Guanidium salt of T(2,4-X)TS has been characterized by X-ray crystallography, and Tolman cone angle of the phosphane has been determined from crystallographic data. The large cone angle (196°, 210°) explains the instability of the rhodium complex. Contrary to the T(2,4-X)TS/rhodium system, the T(2,4-X)TS/iridium catalyst has been found to be stable and effective in hydrogenation of benzaldehyde and caproaldehyde. Rhodium and iridium complexes of trisulfonated triarylphosphanes, TPPTS (tris(3-sulfonatophenyl)phosphane), T(p-A)PTS (tris(3-sulfonato-4-methoxyphenyl)phosphane), T(2,4-X)TS (tris(2,4-dimethyl-5-sulfonatophenyl)phosphane), have been tested in biphasic hydrogenation of benzaldehyde and caproaldehyde. Guanidium salt of T(2,4-X)TS has been characterized by X-ray crystallography.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Inorganica Chimica Acta. - 357 : 10 (2004), p. 3094-3098. -
További szerzők:Bényei Attila (1962-) (vegyész) Bakos József (vegyész)
Pályázati támogatás:OTKA T 032004
OTKA
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4.

001-es BibID:BIBFORM056651
Első szerző:Jakusch Tamás
Cím:Vanadate complexes of 3-hydroxy-1,2-dimethyl-pyridinone : speciation, structure and redox properties / Tamás Jakusch, Éva A. Enyedy, Károly Kozma, Zsófia Paár, Attila Bényei, Tamás Kiss
Dátum:2014
ISSN:0020-1693
Megjegyzések:Several articles were published about the vanadate?3-hydroxy-1,2-dimethyl-pyridinone (Hdhp) system,however, the results are contradictory and not complete: pH-potentiometry and 51V NMR spectroscopywere used to clarify this complicated system. The eleven peaks in the spectra at different chemical shiftswere assigned to ten stoichiometrically different compounds; four of them are new, never identified orassigned before. Besides the simple mono (in two different protonation states) and bis complexes (inthree different protonation states) a tris complex, three dinuclear and a trinuclear complex were foundbased on the 51V NMR spectra measured at different pH values and various metal ion concentrationsand metal-to-ligand ratios. As a joint evaluation of the two methods, overall stability constants were calculatedfor all species.X-ray structure of the potassium salt of the bis complex, [V(V)O2(dhp)2] was also determined. Thetrans effect of the oxido-oxygens results in maltolato-type coordination of the ligand instead of thecatecholate-like chelation.The redox properties of [V(V)O2(dhp)2] and some other prodrug vanadium(V) bis complexes wereinvestigated by spectrophotometry in aqueous solution via their reduction by glutathione (GSH) andL-ascorbic acid (ASC) under strictly anaerobic conditions and by cyclic voltammetry at physiologicalpH. The reduction was found to be much faster by ASC in all cases as compared with GSH and the reactionrate of the reduction of [V(V)O2(dhp)2] was prominently high most probably due to the formation of thesignificantly higher stability of the corresponding vanadium(IV) complex.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Inorganica Chimica Acta. - 420 (2014), p. 92-102. -
További szerzők:Enyedy Éva Anna (1975-) (vegyész) Kozma Károly Paár Zsófia Bényei Attila (1962-) (vegyész) Kiss Tamás
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5.

001-es BibID:BIBFORM008183
Első szerző:Koshino, Nobuyoshi
Cím:Structures of Homoleptic Eight- and Nine-coordinate Uranium(IV) Perchlorate Complexes with Sulfoxide Molecules as Ligands and Spectrophotometric Evidence for Equilibrium between Eight- and Nine-coordination in Liquid State / Nobuyoshi Koshino, Yoshihiro Kachi, Tamás R. Varga, Csaba Attila Bényei, Motoo Shiro, Koichiro Takao, Yasuhisa Ikeda
Dátum:2009
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Uranium(IV)
Megjelenés:Inorganica Chimica Acta. - 362 : 10 (2009), p. 3433-3439. -
További szerzők:Kachi, Yoshihiro Varga Tamás Róbert (1967-) (kémia tanár) Bényei Attila (1962-) (vegyész) Shiro, Motoo Takao, Koichiro Ikeda, Yasuhisa
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