30861
2009
2009
eng
article
1
--
--
--
8-Methoxyneorautenol and radical scavenging flavonoids from Erythrina abyssinica
A new pterocarpan (named 8-methoxyneorautenol) was isolated from the acetone ext. of the root bark of Erythrina abyssinica. In addn., the known isoflavonoid derivs. eryvarin L, erycristagallin and shinpterocarpin were identified for the first time from the roots of this plant. The structures were detd. on the basis of spectroscopic evidence. The new compd. showed selective antimicrobial activity against Trichophyton mentagrophytes. The acetone ext. of the root bark of E. abyssinica showed radical scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The pterocarpenes, 3-hydroxy-9-methoxy-10-(3,3-dimethylallyl)pterocarpene and erycristagallin, were the most active constituents of the roots of this plant and showing dose-dependent activities similar to that of the std. quercetin. [on SciFinder (R)]
http://www.ajol.info/journal_index.php?jid=120&ab=bcse
1011-3924
allegro:1991-2014
10106611
Bulletin of The Chemical Society of Ethiopia. - ISSN 1011-3924. - 23 (2009), 2, S. 205 - 210
Abiy Yenesew
Hannington Twinomuhwezi
Bernard T. Kiremire
Martin N. Mbugua
Peter M. Gitu
Matthias Heydenreich
Martin G. Peter
Institut für Chemie
Referiert
13959
2005
2005
eng
article
1
--
--
--
7a-O-methyldeguelol, a modified rotenoid with an open ring-C, from the roots of Derris trifoloata
From the acetone extract of the roots of Derris trifoliata an isollavonoid derivative, named 7a-O- methyldeguelol, a modified rotenoid with an open ring-C, representing a new sub-class of isollavonoids (the sub-class is here named as rotenoloid), was isolated and characterised. In addition, the known rotenoids, rotenone, deguelin and alpha-toxicarol, were identified. The structures were determined on the basis of spectroscopic evidence. Rotenone and deguelin were identified as the larvicidal principles of the acetone extract of the roots of Derris trifoliata. (c) 2005 Elsevier Ltd. All rights reserved
0031-9422
allegro:1991-2014
10104626
Phytochemistry. - ISSN 0031-9422. - 66 (2005), 6, S. 653 - 657
Abiy Yenesew
E. K. Mushibe
M. Induli
Solomon Derese
Jacob O. Midiwo
Jacques M. Kabaru
Matthias Heydenreich
Andreas Koch
Martin G. Peter
Institut für Chemie
Referiert
23371
1998
1998
eng
article
1
--
--
--
Two prenylated flavanones from stem bark of erythrina burttii
allegro:1991-2014
10088636
Pytochemistry. - 48 (1998), S. 1439 - 1443
Abiy Yenesew
Jacob O. Midiwo
M. Meisner
Matthias Heydenreich
Martin G. Peter
Institut für Chemie
Institut für Organische Chemie und Strukturanalytik
19112
2000
2000
eng
article
1
--
--
--
Two Isoflavanones from the Stem Bark of Erythrina sacleuxii
From the stem bark of Erythrina sacleuxii two new isoflavanones, (R)-5,7-dihydroxy-2',4',5'- trimethoxyisoflavanone (trivial name, (R)-2,3-dihydro-7-demethylrobustigenin) and (R)-5-hydroxy- 2',4',5'-trimethoxy-2'',2''- dimethylpyrano[5'',6'':6,7]isoflavanone (trivial name, (R)-saclenone) were isolated. In addition the known compounds shinpterocarpin, 2,3-dehydrokievitone, abyssinone V, abyssinone V-4'-methyl ether, erythrinasinate and 4'-O-methylsigmoidin B were isolated. The structures were determined on the basis of spectroscopic evidence.
allegro:1991-2014
10089748
Phytochemistry. - 55 (2000), S. 457 - 459
Abiy Yenesew
Jacob O. Midiwo
Matthias Heydenreich
Dirk Schanzenbach
Martin G. Peter
Institut für Chemie
Institut für Organische Chemie und Strukturanalytik
23372
1998
1998
eng
article
1
--
--
--
Four isoflavanones from stem bark of erythrina sacleuxii
allegro:1991-2014
10088638
Pytochemistry. - 49 (1998), S. 247 - 249
Abiy Yenesew
Jacob O. Midiwo
Matthias Heydenreich
Martin G. Peter
Institut für Chemie
Institut für Organische Chemie und Strukturanalytik
16966
2002
2002
eng
article
1
--
--
--
Three iosoflav-3-enes and a 2-arylbenzofuran from the root bark of Erythrina burttii
From the root bark of Erythrina burttii three new isoflav-3-enes, 7,4'-dihydroxy-2'-methoxy-6- (1'',1''-dimethylallyl)isoflav-3-ene (trivial name, burttinol-A), 4'-hydroxy-2'- methoxy-(2'',2''-dimethylpyrano[5'',6'':8,7]isoflav-3-ene (trivial name, burttinol-B), 7,4'-dihydroxy-2'-methoxy-8-(3'',3''-dimethylallyl)isoflav-3-ene (trivial name, burttinol-C), and a new 2-arylbenzofuran, 6,4'-dihydroxy-2'-methoxy-5- (1'',1''-dimethylallyl)-2-arylbenzofuran (trivial name, burttinol-D) were isolated. In addition, the known compounds, abyssinone V-4'-methyl ether, bidwillol A, calopocarpin, erybraedin A, erythrabyssin II, isobavachalcone, phaseollidin and phaseollin were identified. The structures were determined on the basis of spectroscopic evidence.
allegro:1991-2014
10093034
Phytochemistry. - 59 (2002), 3, S. 337 - 341
Abiy Yenesew
Jacob O. Midiwo
S. M. Guchu
Matthias Heydenreich
Martin G. Peter
Institut für Chemie
12159
2006
2006
eng
article
1
--
--
--
Two unusual rotenoid derivatives, 7a-O-methyl-12a-hydroxydeguelol and spiro-13-homo-13-oxaelliptone, from the seeds of Derris trifoliata
The crude methanol extract of the seeds of Derris trifoliata showed potent and dose dependent larvicidal activity against the 2nd instar larvae of Aedes aegypti. From this extract two unusual rotenoid derivatives, a rotenoloid (named 7a-O-methyl-12a-hydroxydeguelol) and a spirohomooxarotenoid (named spiro-13-homo-13-oxaelliptone), were isolated and characterised. In addition a rare natural chromanone (6,7-dimethoxy-4-chromanone) and the known rotenoids rotenone, tephrosin and dehydrodeguelin were identified. The structures were assigned on the basis of spectroscopic evidence. The larvicidal activity of the crude extract is mainly due to rotenone. (c) 2006 Elsevier Ltd. All rights reserved
http://www.sciencedirect.com/science/article/pii/S0031942206000045
10.1016/j.phytochem.2006.01.002
allegro:1991-2014
10102124
Phytochemistry. - 67 (2006), 10, S. 988 - 991
Abiy Yenesew
John T. Kiplagat
Solomon Derese
Jacob O. Midiwo
Jacques M. Kabaru
Matthias Heydenreich
Martin G. Peter
Institut für Chemie
Referiert
15753
2003
2003
eng
article
1
--
--
--
Two prenylated flavonoids from the stem bark of Erythrina burttii
From the stem bark of Erythrina burttii, a new isoflavone, 5,2',4'-trihydroxy-7-methoxy-6-(3- methylbut-2-enyl)isoflavone (trivial name, 7-O-methylluteone) and a new flavanone, 5,7-dihydroxy-4'-methoxy- 3'-(3-methylbutadienyl)-5'-(3-methylbut-2-enyl)flavanone (trivial name, burttinonedehydrate) along with three known isoflavonoids (8-prenylluteone, 3-O-methylcalopocarpin and genistein) were isolated. The structures were detd. on the basis of spectroscopic evidence.
allegro:1991-2014
10095815
Phytochemistry. - 63 (2003), 4, S. 445 - 448
Abiy Yenesew
Beatrice Irungu
Solomon Derese
Jacob O. Midiwo
Matthias Heydenreich
Martin G. Peter
Institut für Chemie
15418
2004
2004
eng
article
1
--
--
--
Anti-plasmodial flavonoids from the stem bark of Erythrina abyssinica
The ethyl acetate extract of the stem bark of Erythrina abyssinica showed anti-plasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC50 values of 7.9 +/- 1.1 and 5.3 +/- 0.7 mug/ml, respectively. From this extract, a new chalcone, 2,3,4,4'-tetrahydroxy-5- prenylchalcone (trivial name 5-prenylbutein) and a new flavanone, 4',7-dihydroxy-3'-methoxy-5'- prenylflavanone (trivial name, 5-deoxyabyssinin II) along with known flavonoids have been isolated as the anti- plasmodial principles. The structures were determined on the basis of spectroscopic evidence. (C) 2004 Elsevier Ltd. All rights reserved
0031-9422
allegro:1991-2014
10104130
Phytochemistry. - ISSN 0031-9422. - 65 (2004), 22, S. 3029 - 3032
Abiy Yenesew
M. Induli
Solomon Derese
Jacob O. Midiwo
Matthias Heydenreich
Martin G. Peter
Hoseah M. Akala
Julia Wangui
Pamela Liyala
Norman C. Waters
Institut für Chemie
Referiert
13951
2005
2005
eng
article
1
--
--
--
Antimicrobial flavonoids from the stem bark of Erythrina burttii
The chloroform extract of the stem bark of Erythrina burttii showed antifungal and antibacterial activities using the disk diffusion method. Flavonoids were identified as the active principles. Activities were observed against fungi and Gram(+) bacteria, but the Gram(-) bacteria Escherichia coli was resistant. (c) 2005 Elsevier B.V. All rights reserved
0367-326X
allegro:1991-2014
10104611
Fitoterapia. - ISSN 0367-326X. - 76 (2005), 5, S. 469 - 472
Abiy Yenesew
Solomon Derese
Jacob O. Midiwo
Christine C. Bii
Matthias Heydenreich
Martin G. Peter
Institut für Chemie
Referiert
53728
2018
2018
eng
141
148
8
23
article
Elsevier
Amsterdam
1
2017-12-22
2017-12-22
--
Alkenyl cyclohexanone derivatives from Lannea rivae and Lannea schweinfurthii
Phytochemical investigation of the CH2Cl2/MeOH (1:1) extract of the roots of Lannea rivae (Chiov) Sacleux (Anacardiaceae) led to the isolation of a new alkenyl cyclohexenone derivative: (4R,6S)-4,6-dihydroxy-6-((Z)-nonadec-14′-en-1-yl)cyclohex-2-en-1-one (1), and a new alkenyl cyclohexanol derivative: (2S*,4R*,5S*)-2,4,5-trihydroxy-2-((Z)-nonadec-14′-en-1-yl)cyclohexanone (2) along with four known compounds, namely epicatechin gallate, taraxerol, taraxerone and β-sitosterol; while the stem bark afforded two known compounds, daucosterol and lupeol. Similar investigation of the roots of Lannea schweinfurthii (Engl.) Engl. led to the isolation of four known compounds: 3-((E)-nonadec-16′-enyl)phenol, 1-((E)-heptadec-14′-enyl)cyclohex-4-ene-1,3-diol, catechin, and 1-((E)-pentadec-12′-enyl)cyclohex-4-ene-1,3-diol. The structures of the isolated compounds were determined by NMR spectroscopy and mass spectrometry. The absolute configuration of compound 1 was established by quantum chemical ECD calculations. In an antibacterial activity assay using the microbroth kinetic method, compound 1 showed moderate activity against Escherichia coli while compound 2 exhibited moderate activity against Staphylococcus aureus. Compound 1 also showed moderate activity against E. coli using the disc diffusion method. The roots extract of L. rivae was notably cytotoxic against both the DU-145 prostate cancer cell line and the Vero mammalian cell line (CC50 = 5.24 and 5.20 μg/mL, respectively). Compound 1 was also strongly cytotoxic against the DU-145 cell line (CC50 = 0.55 μg/mL) but showed no observable cytotoxicity (CC50 > 100 μg/mL) against the Vero cell line. The roots extract of L. rivae and L. schweinfurthii, epicatechin gallate as well as compound 1 exhibited inhibition of carageenan-induced inflammation.
Phytochemistry letters / Phytochemical Society of Europe
10.1016/j.phytol.2017.12.001
1874-3900
1876-7486
wos:2018
WOS:000426096600027
Yenesew, A (reprint author), Univ Nairobi, Dept Chem, POB 30197-00100, Nairobi, Kenya., ayenesew@uonbi.ac.ke
AFIMEGQ intra-ACP project; International Science Program (ISP Sweden) [KEN-02]
2022-02-03T08:59:14+00:00
sword
importub
filename=package.tar
ac28c6aa8cbf71e8f63207403c00bce5
Yenesew, Abiy
false
true
Souaibou Yaouba
Andreas Koch
Eric M. Guantai
Solomon Derese
Beatrice Irungu
Matthias Heydenreich
Abiy Yenesew
eng
uncontrolled
Lannea rivae
eng
uncontrolled
Lannea schweinfurthii
eng
uncontrolled
Alkenyl cyclohexenone
eng
uncontrolled
Alkenyl cyclohexanone
eng
uncontrolled
Anti-inflammatory
eng
uncontrolled
Cytotoxicity
eng
uncontrolled
Antimicrobial
Chemie und zugeordnete Wissenschaften
Institut für Chemie
Referiert
Import
13937
2005
2005
eng
article
1
--
--
--
Three dimeric anthracene derivatives from the fruits of Bulbine abyssinica
From the fruits of Bulbine abyssinica three new dimeric anthracene derivatives, (P)-8,9,1',8'- tetrahydroxy-3,3'-dimethyl[10,7'-bianthracene]-1,4,9',10'- tetraone (trivial name abyquinone A), (10R)-1,4,8,1',8-pentahydroxy-3,3'-dimethyl-[10,7'-bianthracene]9,9',10' (10H)-trione (trivial name abyquinone B), and (10R)-3,4'-dihydro-1,4,8,3',8',9'-hexahydroxy-3,3'- dimethyl-[10,7'-biant hracene]9,1'(10H,2'H)-dione (trivial name abyquinone Q were isolated. Despite their structural differences, these three compounds are connected to each other by the apparently biomimetic conversion of abyquinone C (a preanthraquinonylanthrone with two stereogenic centers) into B (an anthraquinonylanthrone with one stereogenic center) and finally into A (an axially chiral bianthraquinone) under mild conditions, involving a highly efficient center-to-axis chirality transfer. In addition, the known anthraquinones islandicin and chrysophanol were identified. The structures were determined on the basis of spectroscopical evidences, chemical transformations, and quantum chemical CD calculations. (C) 2005 Elsevier Ltd. All rights reserved
0040-4020
allegro:1991-2014
10104597
Tetrahedron. - ISSN 0040-4020. - 61 (2005), 10, S. 2667 - 2674
John M. Wanjohi
Abiy Yenesew
Jacob O. Midiwo
Matthias Heydenreich
Martin G. Peter
M. Dreyer
M. Reichert
Gerhard Bringmann
Institut für Chemie
Referiert
35936
2012
2012
eng
2341
2352
12
14
article
Wiley-VCH
Weinheim
1
--
--
--
Complexation of Palladium(II) with unsaturated Dithioethers a systematic development of highly selective ligands for solvent extraction
There is a demand for new and robust PdII extractants due to growing recycling rates. Chelating dithioethers are promising substances for solvent extraction as they form stable square-planar complexes with PdII. We have modified unsaturated dithioethers, which are known to coordinate PdII, and adapted them to the requirements of industrial practice. The ligands are analogues of 1,2-dithioethene with varying electron-withdrawing backbones and polar end-groups. The crystal structures of several ligands and their palladium complexes were determined as well as their electro- and photochemical properties, complex stability and behaviour in solution. Solvent extraction experiments showed the superiority of some of our ligands over conventionally used extractants in terms of their very fast reaction rates. With highly selective 1,2-bis(2-methoxyethylthio)benzene (4) it is possible to extract PdII from a highly acidic medium in the presence of other base and palladium-group metals.
European journal of inorganic chemistry : a journal of ChemPubSoc Europe
10.1002/ejic.201101406
1434-1948
wos:2011-2013
WOS:000303497900003
Holdt, HJ (reprint author), Univ Potsdam, Inst Chem, Dept Inorgan Chem, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany., holdt@uni-potsdam.de
Arbeitsgemeinschaft industrieller Forschungsvereinigungen "Otto von Guericke" e.V. (AIF); ReMetall Drochow GmbH
Juliane Träger
Tillmann Klamroth
Alexandra Kelling
Susanne Lubahn
Ernst Cleve
Wulfhard Mickler
Matthias Heydenreich
Holger Müller
Hans-Jürgen Holdt
eng
uncontrolled
Renewable resources
eng
uncontrolled
Palladium
eng
uncontrolled
Chelates
eng
uncontrolled
Ligand design
eng
uncontrolled
S li-gands
Institut für Chemie
Referiert
30799
2009
2009
eng
article
1
--
--
--
Synthesis and conformational analysis of naphthylnaphthoxazine derivatives
Four new primary aminonaphthols (4, 5, 9 and 10) were synthesized from 1- or 2-naphthol and 1- or 2- naphthaldehyde via naphthoxazines in modified Mannich condensations. Simple ring-closure reactions of these aminonaphthols with paraformaldehyde, 4-nitrobenzaldehyde, phosgene or 4-chlorophenyl isothiocyanate led to new heterocyclic derivatives. In these transformations, either an sp2 or an sp3 carbon was inserted between the hydroxy and amino groups. The effects of substituents and the naphthyl ring on the conformation were investigated by means of NMR measurements, employing both dipolar and scalar couplings. The structures were confirmed by DFT quantum chemical calculations involving computed coupling constants, intramolecular distances between nuclei and the relative energies of the preferred conformers.
http://www.sciencedirect.com/science/journal/00222860
10.1016/j.molstruc.2009.04.015
0166-1280
allegro:1991-2014
10106000
Journal of molecular structure. - ISSN 0166-1280. - e-ISSN 0022-2860. - 929 (2009), 1-3, S. 58 - 66
Diána Thóth
István Szatmári
Matthias Heydenreich
Andreas Koch
Erich Kleinpeter
Ferenc Fulop
Institut für Chemie
Referiert
30178
2006
2006
eng
article
1
--
--
--
Study of the substituent-influenced anomeric effect in the ring-chain tautomerism of 1-alkyl-3-aryl-naphth[1,2- e][1,3]oxazines
The stabilities of the trans (B) and cis (C) tautomeric ring forms that are experimentally observed in the ring- chain tautomeric interconversion of 1-alkyl-3-aryl-2,3-dihydro-1H-naphth[1,2-e][1,3]oxazines has been investigated. Stability differences are explained by the analysis of the natural bond orbital results for the lone pairs of electrons that are on the heteroatoms in the oxazine ring system and by regression analysis of the calculated 13C NMR chemical shift values.
http://onlinelibrary.wiley.com/doi/10.1002/ejoc.200600563/pdf
10.1002/ejoc.200600563
allegro:1991-2014
10103773
European journal of organic chemistry. - (2006), 20, S. 4670 - 4675
Istvan Szatmari
Diana Toth
Andreas Koch
Matthias Heydenreich
Erich Kleinpeter
Ferenc Fulop
Institut für Chemie
Referiert
34742
2013
2013
eng
7455
7465
11
35
69
article
Elsevier
Oxford
1
--
--
--
Unexpected isomerization of new naphth[1,3]oxazino[2,3-a] isoquinolines in solution, studied by dynamic NMR and supported by theoretical DFT computations
Through the reactions of 1-aminomethyl-2-naphthol and substituted 1-aminobenzyl-2-naphthols with 3,4-dihydroisoquinoline or 6,7-dimethoxy-3,4-dihydroisoquinoline under microwave conditions, naphth[1,2-e][1,3]oxazino[2,3-a]-isoquinoline derivatives were prepared in good yields. The latter reaction was extended by using 2-aminoarylmethyl-1-naphthols, leading to isomeric naphth-[2,1-e][1,3]oxazino[2,3-a] isoquinolines. Beside the detailed NMR spectroscopic and theoretical study of both stereochemistry and dynamic behaviour of these new conformational flexible heterocyclic ring systems an unexpected dynamic process between two diastereomers was observed in solution, studied by variable temperature H-1 NMR spectroscopy and the mechanism proved by theoretical DFT computations.
Tetrahedron
10.1016/j.tet.2013.06.094
0040-4020
wos:2011-2013
WOS:000322557500035
Fulop, F (reprint author), Univ Szeged, Hungarian Acad Sci, Inst Pharmaceut Chem, Eotvos U 6, H-6720 Szeged, Hungary., fulop@pharm.u-szeged.hu; ekleinp@uni-potsdam.de
Bolyai Janos Fellowship
Istvan Szatmari
Matthias Heydenreich
Andreas Koch
Ferenc Fulop
Erich Kleinpeter
eng
uncontrolled
3,4-Dihydroisoquinoline
eng
uncontrolled
Aminonaphthol
eng
uncontrolled
Dynamic NMR spectroscopy
eng
uncontrolled
DFT calculations
eng
uncontrolled
Conformational analysis
Institut für Chemie
Referiert
48916
2019
2019
eng
961
971
11
7
8
article
Wiley-VCH
Weinheim
1
2019-07-16
2019-07-16
--
Ortho-Quinone methide driven synthesis of new O,N- or N,N-Heterocycles
To synthesize functionalized Mannich bases that can serve two different types of ortho-quinone methide (o-QM) intermediates, 2-naphthol and 6-hydroxyquinoline were reacted with salicylic aldehyde in the presence of morpholine. The Mannich bases that can form o-QM and aza-o-QM were also synthesized by mixing 2-naphthol, 2-nitrobenzaldehyde, and morpholine followed by reduction of the nitro group. The highly functionalized aminonaphthol derivatives were then tested in [4+2] cycloaddition with different cyclic imines. The reaction proved to be both regio- and diastereoselective. In all cases, only one reaction product was obtained. Detailed structural analyses of the new polyheterocycles as well as conformational studies including DFT modelling were performed. The relative stability of o-QMs/aza-o-QM were also calculated, and the regioselectivity of the reactions could be explained only when the cycloaddition started from aminodiol 4. It was summarized that starting from diaminonaphthol 25, the regioselectivity of the reaction is driven by the higher nucleophilicity of the amino group compared with the hydroxy group. 12H-benzo[a]xanthen-12-one (11), formed via o-QM formation, was isolated as a side product. The proton NMR spectrum of 11 proved to be very unique from NMR point of view. The reason for the extreme low-field position of proton H-1 could be accounted for by theoretical calculation of structure and spatial magnetic properties of the compound in combination of ring current effects of the aromatic moieties and steric compression within the heavily hindered H(1)-C(1)-C(12b)-C(12a)-C(12)=O structural fragment.
ChemistryOpen : including thesis treasury
10.1002/open.201900150
31341756
2191-1363
wos:2019
WOS:000477965100016
Szatmari, I; Fulop, F (reprint author), Univ Szeged, Inst Pharmaceut Chem, Eotvos U 6, H-6720 Szeged, Hungary.; Szatmari, I; Fulop, F (reprint author), Univ Szeged, MTA SZTE Stereochem Res Grp, Eotvos U 6, H-6720 Szeged, Hungary.; Szatmari, I; Fulop, F (reprint author), Univ Szeged, Interdisciplinary Excellence Ctr, Inst Pharmaceut Chem, Szeged, Hungary.; Kleinpeter, E (reprint author), Univ Potsdam, Dept Chem, Karl Liebknecht Str 4-25, D-14476 Golm, Germany., szatmari.istvan@pharm.u-szeged.hu; ekleinp@uni-potsdam.de; fulop@pharm.u-szeged.hu
Ministry of National Economy, National Research Development and Innovation Office [GINOP-2.3.2-15-2016-00038]; EUEuropean Union (EU) [EFOP-3.6.1-16-2016-00008]; Ministry of Human Capacities, Hungary Grant [20391-3/2018/FEKUSTRAT]
2021-01-14T12:12:52+00:00
sword
importub
filename=package.tar
85d20a0245facff2807fd37780c5e072
Szatmari, Istvan
Kleinpeter, Erich
Fülöp, Ference
false
true
CC-BY-NC-ND - Namensnennung, nicht kommerziell, keine Bearbeitungen 4.0 International
Istvan Szatmari
Khadija Belasri
Matthias Heydenreich
Andreas Koch
Erich Kleinpeter
Ferenc Fulop
eng
uncontrolled
ortho-quinone methide (o-QMs)
eng
uncontrolled
modified Mannich reaction
eng
uncontrolled
cycloaddition
eng
uncontrolled
NMR spectroscopy
eng
uncontrolled
conformational analysis
eng
uncontrolled
DFT calculations
Chemie und zugeordnete Wissenschaften
Institut für Chemie
Referiert
Import
Gold Open-Access
DOAJ gelistet
13894
2005
2005
eng
article
1
--
--
--
One- and two-photon photochemistry and photophysics of poly(arylenevinylene)s containing a biphenyl moiety
Photochemical and photophysical properties were investigated for poly(arylenevinylene)s containing a flexible biphenyl "hinge" unit by applying one-photon (OP) and two-photon (TP) excitation to explore excited-state properties. The poly(arylenevinylene)s were poly[(2,5-dihexyloxy-p-phenylenevinylene)-alt-(4,4'-dihexyloxy-3,3'-biph enylenevinylene)] (1), poly[(2,5-dihexyloxy-p-phenylenevinylene)-alt-(2,2'-dihexyloxy-3,3'-biph enylenevinylene)] (2), and poly[(2,5-dihexyloxy-p-phenylenevinylene)-alt-(2,2'-biphenylene-vinylene )] (3). Effective emission quantum yields and related photonic properties were evaluated on a realistic per-chromophore basis using effective conjugation lengths based on the Strickler-Berg relationship. intramolecular photocyclization was deduced to occur in the one case where the biphenyl molecular connectivity permitted the reaction, based on matrix- assisted loser desorption/ionization time-of-flight (MALDI-TOF), heteronuclear multiple-quantum coherence (HMQC)-NMR, and gel-permeation chromatography (GPC) results. The various photoprocesses could be induced by either OP or TP excitation, though the first excited singlet state is the photoactive state. The higher excitation energy 1 of the TP excited state favors indirect population of the S, state by electronic coupling between the TP and OP excited states [lambda(max)(TPE) (nm): 726; delta (GM)([9]): 1 = 229, 2 = 215, 3 = 109). Photochemical processes occurring from the lowest OP excited state (S-1) could therefore also be indirectly induced by TP excitation
1439-4235
allegro:1991-2014
10104342
Chemphyschem. - ISSN 1439-4235. - 6 (2005), 2, S. 267 - 276
Veronika Strehmel
A. M. Sarker
P. M. Lahti
F. E. Karasz
Matthias Heydenreich
Hendrik Wetzel
Sophie Haebel
Bernd Strehmel
Institut für Chemie
Referiert
Institut für Physikalische Chemie und Theoretische Chemie
47839
2019
2019
eng
9
46
75
article
Elsevier
Oxford
1
2019-10-07
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1-Methylthio-1-phenyl-1-silacyclohexane: Synthesis, conformational preferences in gas and solution by GED, NMR and theoretical calculations
1-Methylthio-1-phenyl-1-silacyclohexane 1, the first silacyclohexane with the sulfur atom at silicon, was synthesized and its molecular structure and conformational preferences studied by gas-phase electron diffraction (GED) and low temperature C-13 and Si-29 NMR spectroscopy (LT NMR). Quantum-chemical calculations were carried out both for the isolated species and solvate complexes in gas and in polar medium. The predominance of the 1-MeSaxPheq conformer in gas phase (1-Ph-eq :1-Ph-ax = 55:45, Delta G degrees = 0.13 kcal/mol) determined from GED is consistent with that measured in the freon solution by LT NMR (1-Ph-eq:1-Ph-ax = 65:35, Delta G degrees = 0.12 kcal/mol), the experimentally measured ratios being close to that estimated by quantum chemical calculations at both the DFT and MP2 levels of theory. (C) 2019 Elsevier Ltd. All rights reserved.
Tetrahedron
10.1016/j.tet.2019.130677
0040-4020
wos:2019
130677
WOS:000497251300010
Shainyan, BA (reprint author), Russian Acad Sci, Siberian Div, AE Favorsky Irkutsk Inst Chem, 1 Favorsky St, Irkutsk 664033, Russia.; Kleinpeter, E (reprint author), Univ Potsdam, Chem Inst, Karl Liebknecht Str 24-25, D-14476 Potsdam, Golm, Germany., bagrat@irioch.irk.ru; ekleinp@uni-potsdam.de
Ministry of Education and Science of the Russian FederationMinistry of Education and Science, Russian Federation
importub
2020-10-06T07:27:11+00:00
filename=package.tar
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true
Bagrat A. Shainyan
Elena N. Suslova
Tran Dinh Phien
Sergey A. Shlykov
Matthias Heydenreich
Erich Kleinpeter
eng
uncontrolled
1-Methylthio-1-phenyl-1-silacyclohexane
eng
uncontrolled
Conformational analysis
eng
uncontrolled
Gas phase electron diffraction
eng
uncontrolled
Low-temperature C-13 and Si-29 NMR
eng
uncontrolled
DFT and MP2 calculations
Chemie und zugeordnete Wissenschaften
Institut für Chemie
Referiert
Import
37669
2014
2014
eng
448
452
5
8
52
article
Wiley-Blackwell
Hoboken
1
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Conformational equilibrium and dynamic behavior of bis-N-triflyl substituted 3,8-diazabicyclo[3.2.1]octane
Restricted rotation about the N-S partial double bonds in a bis-N-triflyl substituted 3,8-diazabicyclo[3.2.1]octane derivative 1 has been frozen at low temperature (Delta G* = 11.6 kcal mol(-1)), and the existence of all four rotamers about the two N-S bonds, 3-in, 8-in, 3-in, 8-out, 3-out, 8-in, and 3-out, 8-out, respectively, proved experimentally by NMR spectroscopy and theoretically by DFT and MP2 calculations. Copyright (C) 2014 John Wiley & Sons, Ltd.
Magnetic resonance in chemistry
10.1002/mrc.4086
24915750
0749-1581
1097-458X
wos:2014
WOS:000340535300006
Kleinpeter, E (reprint author), Univ Potsdam, Inst Chem, Karl Liebknecht Str 24-25, D-14476 Golm, Germany., ekleinp@uni-potsdam.de
Bagrat A. Shainyan
Mikhail Yu Moskalik
Matthias Heydenreich
Erich Kleinpeter
eng
uncontrolled
NMR
eng
uncontrolled
H-1
eng
uncontrolled
C-13
eng
uncontrolled
F-19
eng
uncontrolled
Dynamic NMR
eng
uncontrolled
Conformational equilibrium
eng
uncontrolled
restricted N-S rotation
Institut für Chemie
Referiert