| | 1 | Author
| Hans Friedewold, Wolfgang Brockner | Requires cookie* | | | Title
| P  | | | | Abstract
| a r ti c u la r V ib r a tio n S p e c tr u m o f A n tim o n y T ric h lo rid e C a u s e d by B o n d F lu c tu a tio n Vibration spectra of solid and molten antimony trichloride were recorded. In the solid state, vibration frequencies in addition to those of the SbCl3 molecules with their C3v symmetry indicate bond fluctuations according to 2 SbCl3 Sb++ SbClg. | | | |
Reference
| Z. Naturforsch. 46a, 595—598 (1991); received April 27 1991 | | | |
Published
| 1991 | | | |
Keywords
| SbCl3, Vibration spectrum Bond fluctuation, Electron transfer | | | |
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| default:Reihe_A/46/ZNA-1991-46a-0595.pdf | | | | Identifier
| ZNA-1991-46a-0595 | | | | Volume
| 46 | |
| 2 | Author
| Wolfgang Kaim | Requires cookie* | | | Title
| Koordinationschemie reduzierter N-Heterozyklen. Komplexe des Pyrazin-Radikalanions mit Phenylmetallkationen +MPh von Beryllium, Magnesium und Zink Coordination Chemistry of Reduced N-Heterocycles. Complexes of Pyrazine Anion Radical with Phenyl Metal Cations + MPh of Beryllium, Magnesium and Zinc | | | | Abstract
| The diphenyls MPh2 (M = Be, Mg, Zn, Cd, Hg) have been reacted with pyrazine (Pz) in tetrahydrofuran. Only the magnesium derivative undergoes electron transfer to yield the 1:1 radical complex [Pz(MgPh)] -. However, in the presence of sodium or potassium persistent 1:2 complexes [Pz(MPh)2]t are formed with M = Be, Mg, Zn. Use of the higher homologues CdPh2 and HgPh2 leads to reduction to the metals. The 1:2 complexes have been characterized by ESR spectroscopy; metal coupling constants of 9 Be, 25 Mg and 67 Zn could be determined in natural isotopic abundance. | | | |
Reference
| Z. Naturforsch. 36b, 1110—1116 (1981); eingegangen am 4. Mai 1981 | | | |
Published
| 1981 | | | |
Keywords
| Pyrazine, Electron Transfer, Group II Aryls, Radical Complexes, ESR Spectra | | | |
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| default:Reihe_B/36/ZNB-1981-36b-1110.pdf | | | | Identifier
| ZNB-1981-36b-1110 | | | | Volume
| 36 | |
| 4 | Author
| Olefine, Hans-Dieter Hausen, Christian Bessenbacher, Wolfgang Kaim | Requires cookie* | | | Title
| Elektronenreiche | | | | Abstract
| Struktur und Elektrontransfer-Reaktivität des cyclisch <7/7r-hyperkonjugierten Carbosilans 3,3,6,6-Tetrakis(trimethylsilyl)-l,4-cyclohexadien Electron Rich Olefins, 2 Structure and Electron Transfer Reactivity of the Cyclically a/jr-Hyperconjugated Carbosilane 3,3,6,6-Tetrakis(trimethylsilyl)-l,4-cyclohexadiene Crystal and molecular structure analysis of the title compound 1, a most electron rich carbosi-lane, exhibits a shallow boat conformation for the cyclohexadiene ring which is shielded by four bulky Me 3 Si groups. Multiple hyperconjugative interaction occurs between the two non-conju-gated olefinic JZ systems and the four rather long (192 pm) carbon-silicon o bonds which form an angle of about 34° with the assumed JZ axis. The HOMO destabilization caused by this unique structural arrangement explains the energetically facile formation and subsequent reactivity of the cation radical 1 + which was found to undergo oxidative desilylation to the aromatic l,4-bis(tri-methylsilyl)benzene precursor in the single electron transfer reaction with TCNE. | | | |
Reference
| Z. Naturforsch. 43b, 1087—1093 (1988); eingegangen am 11. Mai 1988 | | | |
Published
| 1988 | | | |
Keywords
| Organosilicon Compounds, Molecular Conformation, Electron Transfer, Hyperconjugation, Electronic Structure | | | |
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| default:Reihe_B/43/ZNB-1988-43b-1087.pdf | | | | Identifier
| ZNB-1988-43b-1087 | | | | Volume
| 43 | |
| 5 | Author
| Fausto Calderazzo, Guido Pam, M. Artin Sperrlea, Ulli Englertb | Requires cookie* | | | Title
| Electron-and Ligand-Transfer Reactions Involving N,N-Dialkylcarbamates. Synthesis and Molecular Structure of V jIf^ -C C sH ^ yC ^ C N t^ H ^ h | | | | Abstract
| Electron-and ligand-transfer reactions o f low-valent organom etallic com pounds o f titanium and vanadium with N,N-dialkylcarbam ates o f titanium(IV) are reported. The reaction o f VCp2 (Cp = ^-cyclopentadienyl) with T i(0 2C N E t2)4 affords, inter alia, the dimeric vana-dium(III) N ,N-diethylcarbam ato derivative V2Cp2(0 2C N E t2)4 which has been studied by X-ray diffraction methods. Crystal data; triclinic, space group P i; a = 10.802(2), b = 11.004(1), c = 8.960(1) Ä; a = 112.879(9), ß = 102.66(1), y = 102.42(1)°; V = 902.3(6) A 3; Z = 1; F(000) = 368, gcalc = 1.282 g em -3; n = 5.47 cm -1. It consists o f a centrosymmetric dimer, the two vanadium atom s being surrounded by four oxygen atom s o f the bridging N,N-diethylcar-bamato groups and by the cyclopentadienyl ligand. The metal atom exhibits a distorted square-pyramidal coordination geometry with the oxygen atom s occupying the basal plane. The reaction o f TiCp2(CO)2 or Vmes2 (mes = //6-l,3 ,5 -M e3C6H 3) with T i(0 2C N E t2)4 affords Ti(III) and V(III) N,N-diethylcarbam ato derivatives by a simultaneous ligand-and electron-transfer reaction. M agnesium N ,N-diisopropylcarbam ate, M g (0 2CNPr'2)2, has been obtained by a ligand-transfer reaction between M gCp2 and T i(0 2CNPr'2)3. | | | |
Reference
| Z. Naturforsch. 47b, 389 (1992); received A ugust 9 / October 16 1991 | | | |
Published
| 1992 | | | |
Keywords
| N, N-D ialkylcarbam ates, Vanadium, Titanium, Cyclopentadienyl, Electron Transfer | | | |
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| default:Reihe_B/47/ZNB-1992-47b-0389.pdf | | | | Identifier
| ZNB-1992-47b-0389 | | | | Volume
| 47 | |
| 7 | Author
| W. S. Cohen, J. R. Barton | Requires cookie* | | | Title
| The Use of 0 2-Evolving Subchloroplast Particles to Study Acceptor and Inhibitor Sites on the Reducing Side of Photosystem II | | | | Abstract
| Photosystem II particles that retain the ability to evolve 0 2 have been used to exam ine acceptor and inhibitor sites in the photosynthetic electron transfer chain between Q and plasto-quinone. Employing the water to dichlorobenzoquinone reaction to assay photosystem II activity, we have demonstrated that electron transport in thylakoids and particles is equally sensitive to inhibition by D C M U , dinoseb, metribuzin, H Q N O and DBMIB. Based on differential sensitivity to inhibition by D C M U vs. H Q N O or DBMIB, we suggest that when synthetic quinones, e.g. 2,6-dichlorobenzoquinone operate as Hill reagents in particles they are reduced primarily by the plastoquinone pool. W hen synthetic quinones, e.g. 5,6-m ethylenedioxy-2,3-dim ethyl benzoquinone act as autoxidizable acceptors they accept electron from the Q /B com plex at a point that is located between the D C M U and H Q N O (DBM IB) inhibition sites. | | | |
Reference
| Z. Naturforsch. 38c, 793—798 (1983); received April 26 1983 | | | |
Published
| 1983 | | | |
Keywords
| Thylakoids, Photosystem II Particles, Q uinones, Inhibitors, Electron Transfer | | | |
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| default:Reihe_C/38/ZNC-1983-38c-0793.pdf | | | | Identifier
| ZNC-1983-38c-0793 | | | | Volume
| 38 | |
| 8 | Author
| Naoki Toshima, Yumi Yamaji, Toshiharu Teranishi, Tetsu Yonezawa | Requires cookie* | | | Title
| P | | | | Abstract
| h o to s e n s itiz e d R e d u c tio n o f C a r b o n D io x id e in S o lu tio n U s in g N o b le -M e ta l C lu s te rs f o r E le c tr o n T r a n s f e r Dedicated to Prof. Hitoshi Ohtaki on the occasion of his 60th birthday Carbon dioxide was reduced to methane by visible-light irradiation of a solution composed of tris(bipyridine)ruthenium(III) as photosensitizer, ethylenediaminetetraacetic acid disodium salt as sacrificial reagent, methyl viologen as electron relay, and a colloidal dispersion of polymer-protected noble-metal clusters, prepared by alcohol-reduction, as catalyst. Among the noble-metal clusters examined, Pt clusters showed the highest activity for the formation of methane as well as hydrogen. In order to improve the activity, oxidized clusters and bimetallic clusters were also applied. For example, the CH4 yield in 3-h irradiation increased from 51 x 10"3 |xmol with unoxidized Pt clusters to 72 x 10" 3 pmol with partially oxidized ones. In the case of Pt/Ru bimetalic systems, the improve ment of the catalytic activity by air treatment was much greater than in case of monometallic clusters. | | | |
Reference
| Z. Naturforsch. 50a, 283—291 (1995); received October 4 1994 | | | |
Published
| 1995 | | | |
Keywords
| Carbon dioxide, Photosensitized reduction, Electron transfer, Metal cluster, Colloidal catalyst | | | |
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| default:Reihe_A/50/ZNA-1995-50a-0283.pdf | | | | Identifier
| ZNA-1995-50a-0283 | | | | Volume
| 50 | |
| 9 | Author
| Z. Naturforsch | Requires cookie* | | | Title
| Kinetics of Electron Transfer between Q A and Q B in Wild Type and Herbicide-Resistant Mutants of Chlamydomonas reinhardtii | | | | Abstract
| A n ton y R . C ro fts*, Irene B aroli, D avid K ra m e r, and Shinichi T a o k a Biophysics Division and *D epartm ent o f M icrobiology, University o f Illinois at U rbana-Cham paign, U rb ana, We have investigated the electron transfer kinetics for reduction o f plastoquinone by photo system II in six m utant strains o f Chlamydomonas reinhardtii by following the decay o f the high fluorescence state after flash activation, and com pared the separate reactions of the two-electron gate with those o f a wild type strain. By analysis o f the electron transfer kinetics, and separate measurement o f the equilibrium constant for stabilization o f the bound semiquinone after one flash, we have been able to deconvolute the contributions o f rate constants and equi librium constants for plastoquinone binding and electron transfer to the overall process. Two mutations, S 264 A and A 251 V, led to a marked slowing o f kinetics for reduction of plastoqui none to the bound semiquinone. In S 2 6 4 A , the second electron transfer was also slower, but was normal in A 2 5 1 V. In m utant G 2 5 6 D , the electron transfer kinetics were normal after the first flash, but slowed after the second. In mutants L 2 5 7 F , V 2 1 9 I, and F 2 5 5 Y , the electron transfer kinetics after both flashes were similar to those in wild type. We discuss the results in terms of a model which provides a description o f the mechanism o f the two-electron gate in terms of measured kinetic and equilibrium constants, and we give values for these parameters in all strains tested. | | | |
Reference
| Z. Naturforsch. 48c, 259 (1993); received December 10 1992 | | | |
Published
| 1993 | | | |
Keywords
| Electron Transfer, Kinetics, Tw o-Electron G ate, Herbicide Resistance, Photosystem II | | | |
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| default:Reihe_C/48/ZNC-1993-48c-0259.pdf | | | | Identifier
| ZNC-1993-48c-0259 | | | | Volume
| 48 | |
| 10 | Author
| HeinzG 0 Becker, Dietmar Pfeifer, Reiner Radeglia | Requires cookie* | | | Title
| Democratic Republic | | | | Abstract
| 13 C and 15 N photo-CIDNP effects were determined for the reversible electron transfer from pyrene to arene diazonium salts on excitation of the charge transfer band at 360 nm. The diazonium salts being the products of back electron transfer ("cage products") show enhanced absorption for 13 C(1) and the 15 N-enriched diazonium group, whereas the escape products, ArH or lö N2, respectively, yield emission signals. It was shown that the inten-sities of the CIDNP effects depend on the rates of intersystem crossing kjSC within the geminate radical pair, i.e. on the magnetic nucleus used as a probe of the CIDNP effect. Using iH, 13 C or 15 N the time domain of observation can be manipulated in the ranges of 90-100 ns, 15-20 ns and 3-5 ns, respectively. Furthermore, the CIDNP intensities depend on the proper balance of the rate of electron back transfer, k_e, and the rate kp of formation of the escape product. Since k_e increases with increasing energy of the geminate radical pair, this balance and therefore the CIDNP intensities vary according to the substituent present and the electron donor used. | | | |
Reference
| Z. Naturforsch. 38b, 1591—1597 (1983); received April 6 1983 | | | |
Published
| 1983 | | | |
Keywords
| Photochemistry, Dediazoniation, Electron Transfer, Chemical Induced Nuclear Polarization (CIDNP), Arene Diazonium Salts | | | |
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| default:Reihe_B/38/ZNB-1983-38b-1591.pdf | | | | Identifier
| ZNB-1983-38b-1591 | | | | Volume
| 38 | |
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