bluuebunny/crossref_metadata_2025_split huggingface dataset:
13C‐NMR‐Untersuchung der interannularen Konjugation in substituierten Pyrazolen
Authors: Mögel L. , Schulz M. , Radeglia R. , Osten H. J. 
Published: December 2004

13C‐N.M.R. Investigation of Interannular Conjugation in Substituted PyrazolesThe correlation of the 13C‐chemical shifts with the Hammet values for substituted 3‐anilino‐1, 5‐diphenylpyrazoles (1a–k) and substituted 3‐methyl‐1, 5‐diphenylpyrazoles (2a–g) provides evidence for extensive interannular conjugation only between the N‐benzene‐and the pyrazole rings, whereas in the capto‐dative disubstituted system 1 extensive conjugation through the whole molecule is possible. The chemical shifts correlate well with the HMO‐calculated π‐electron densities. From a comparison of the chemical shifts of unsubstituted 1 and diphenylamine it can be concluded that the 1,5 ‐diphenylpyrazol‐3‐yl group has the same electronic effect as the phenyl group.
Zur Beeinflussung des Ionisations‐Dissoziationsgleichgewichtes von Tritylhalogenidlösungen in Methylenchlorid bei Zugabe von Styren
Authors: Heublein Günther , Bauerfeind Dietmar 
Published: December 2004

Influence of Styren Addition on the Ionization‐Dissociation Equilibrium of Trityl Halides in Methylene DichlorideThe ionization‐dissociation equilibrium in solutions of trityl halides in methylene dichloride is effected by the addition of π‐donors as a function of the temperature. The intensity of the trityl absorption of trityl fluoride and trityl chloride is decreased as it can be shown by u.v.‐spectroscopy. The trityl absorption of trityl bromide solutions in methylene dichloride is very sensitive towards temperature changes. Measurements of the equilibrium constants for the ionization ‐ dissociation‐equilibrium, when styrene is added to the solution, indicate a specific solvation effect by the styrene molecules, however, a stabilization of ion pairs by specific solvation due to styrene molecules does not occur.
Dicyclopentadienoxidation. IV. Oxidation von 4,5‐ und 8,9‐Dihydro‐dicyclopentadien
Authors: Schnurpfeil D. , Lauterbach G. 
Published: December 2004

Dicyclopentadiene Oxidation. IV. Oxidation of 4,5‐ and 8,9‐Dihydro‐dicyclopentadieneA mixture of exo‐ and endo‐4,5‐dihydro‐dicyclopentadiene 5 and also pure endo‐8,9‐dihydro‐dicyclopentadiene 7 and pure exo‐dicyclopentadiene 10 was oxidized in the absence and in the presence of catalysts. The compounds containing the norbornene structure mainly gave the corresponding exo‐epoxides. No catalytic effects were observed in the formation of these nor‐bornene epoxides. Compound 7 containing only the cyclopentene structure mainly yielded the corresponding hydroperoxide 9. In this case a catalytic effect of epoxidation catalysts was observed: in the presence of such catalysts the epoxide was increased.The results obtained prove the mechanism of dicyclopentadiene oxidation proposed by us.
Acylierung von Heterocyclen mit Kohlensäurederivaten. IV. Umsetzung von Benzoxazolin 2‐thion mit Arylcyanaten. Kinetik und Mechanismus
Authors: Glatt Hans‐Horst , Bacaloglu Radu , Csunderlik Carol , Muntean Doina , Martin Dieter 
Published: December 2004

Acylation of Heterocycles with Carbonic Acid Derivatives. IV. Reaction of Benzoxazolin‐2‐thione with Aryl Cyanates. Kinetics and MechanismThe arylcyanate benzoxazoline‐2‐thione (1) reaction in the presence and absence of the tertiary amines yields 1‐aryloxyiminocarbonylbenzoxazoline‐2‐thione (2) and 2‐thiocyanatobenzoxazole (4). A mechanism is proposed based on the influences of the reactants concentration, the concentration and basicity of tertiary amines, the solvent‐water concentration, the arylcyanate substituents electronic effects on the reaction rate and the apparent activation parameters. This mechanism consists in the nucleophilic attack of the benzoxazoline‐2‐thione S‐atom on the cyanate, followed by rearrangement through a four‐center transition state.
Quantenchemische Berechnungen an Radikalen vom Allyltyp: Cycloalkenyl‐ und Cycloalk‐1‐enylmethylradikale
Authors: Ziegler U. , Ondruschka B. 
Published: December 2004

Quantum‐Chemical Calculations on Allyl‐Type Radicals: Cycloalkenyl‐ and Cycloalk‐1‐enylmethyl RadicalsThe ability of the MINDO/3‐HE‐method for predicting various molecular properties was tested for cycloalkenyl‐ (1 to 4), cycloalk‐1‐enylmethyl‐(5 to 8), and for the resonance‐stabilized cyclic radicals (9 to 12). Close by it was established that the calculated heats of formation are largely correct. The electronic distribution in the allylic part of 1 to 12 is evidently too levelled.Based on the defination of allyl resonance energy (ARE ‐ SZWARC (1948)) a mean value for the ARE of 1 to 8 is derived to 55 ± 12 kJ · mol−1.
Darstellung von β‐substituierten trans‐Ethylen‐diphenylphosphinen und ‐sulfiden durch P(O)‐ und P(S)‐aktivierte Olefinierung
Authors: Gloyna Dieter 
Published: December 2004

Preparation of β‐Substituted trans‐Ethylene Diphenylphosphines and Sulphides by P(0) and P(S)‐activated OlefinationMethylene bis‐diphenylphosphine monoxide (3c) in tuluene reacts regiospecifically and stereoselectively with aldehydes in the presence of potassium tert‐butoxide to ß‐substituted transethylene diphenylphosphines 6, which can be oxidized to the sulphides 2 by sulphur in acetone. These sulphides 2 are to be obtained also directly from methylene bis‐diphenylphosphine oxide sulphide 3b and methylene bis‐diphenylphosphine disulphide 3d, respectively, under the same olefination conditions. But the yields are smaller and the purification of the raw products is much more difficult, if 3d is used.
Anomalous Reactions of Cyanide with Two Hindered Aromatic Aldehydes
Authors: Gore P. H. , Gupta S. D. , Obaji G. A. 
Published: December 2004

Abstract9‐Anthraldehyde (1), under the conditions of a benzoin condensation, yields 9‐anthracenecarbonitrile (2). 9‐Cyano‐10‐anthraldehyde (6) has been shown to be the likely intermediate in this reaction. Mesitaldehyde (7), under similar conditions, yields 2‐hydroxy‐2‐mesitylethanoic amide (8).
Elektrochemische Reduktion von 4‐substituierten 7‐Nitro‐benz‐2,1,3‐oxadiazolderivaten
Authors: Heberer H. , Matschiner H. 
Published: December 2004

Electrochemical Reduction of 4‐Substituted 7‐Nitro‐benzo‐furazansThe electrochemical properties of 4‐methoxy‐, hydroxy‐, alkylamino, and arylaminosubstituted 7‐nitrobenzofurazans (1a–1h) are studied between pH 1,7 and 11,6 by use of buffer solutions containing different portions of various organic solvents. Reduction waves which are present in polarograms, are well reproducible and practicable for qualitative and quantitative analysis of amines. A mechanism of reduction is suggested by reason of polarographic and coulometric results. The half wave potentials are correlated with various substituent constants. A value of ϱ = + 0,32 follows from the determination of the reaction constant from the slope of the E 1/2 – σp – relation for the polarographic reduction of each nitro‐function.
Lichtinitiierte Polymer‐ und Polymerisationsreaktionen. 14. Radikalische Photopolymerisation mit Kaliumtrisoxalatocobaltat‐Aryloniumsalz‐Systemen
Authors: Baumann H. , Strehmel B. , Timpe H.‐J. , Lammel U. 
Published: December 2004

Light Induced Polymer and Polymerization Reactions. 14. Radical Photopolymerization by Potassium Trisoxalato Cobaltate Arylonium Salts Systems.The photopolymerization of acrylamide (AA) by trisoxalato cobaltate ([Co(ox)3]3⊖) is inefficient because the produced nucleophilic ·CO2⊖‐radicals are oxidized or they terminate with polymer radicals. If onium compounds are added to this system the initiation efficiency is increased as follows : p‐CH3OC6H4N2⊕>Ph2I⊕>PhCOCH2S(CH3)2⊕>Ph3S⊕. By means of quantum yield measurements a mechanism was proposed including the electron transfer from ·CO2⊖ to onium compounds. The produced radicals also initiate the polymerization of AA. The exponent m of the polymerization rate (vp ≈︁ [AA]m) is decreased from 1.4 to 1.1 in the presence of Ph2I⊕, deciding the decrease of termination reaction between ·CO2⊖ and polymer radicals. In comparison with K3[Fx(ox)3] the corresponding cobalt complex possesses higher polymerization quantum yields for AA.
Synthese und Charakterisierung von Polychlorisobutenen
Authors: Schulze K. , Hartmann S. , Krüger H. , Mühlstädt M. , Richter C. , Richter H. 
Published: December 2004

Synthesis and Characterization of Polychlorinated IsobutenesThe preparation of polychlorinated methallylic chlorides by continuous chlorination of isobutene with different ratios of chlorine and following HCl‐elimination is described. The structure is proved by reaction of the polychlorinated isobutenes with sodium thiolacetate and potassium thiocyanate and by spectroscopic methods.
Quantenchemische Untersuchungen zur Farbe und Stereodynamik von acyclischen Azinen. XIV. Zum Chromophorsystem der isomeren Anthraldazine in den niedrigsten Sp(ππ*)‐Zuständen
Authors: Gustav K. , Vettermann S. 
Published: December 2004

Quantum Chemical Studies on Colour and Stereodynamics of Acyclic Azines. XIV. On the Chromophoric System of the Isomeric Anthraldazines in the Lowest Sp (ππ*) StatesThe chromophoric system of the isomeric anthraldazines have been studied quantumchemically by means of the PPP‐CA and LHM‐CI methods. On the basis of a definite substructure being in analogy to the molecular geometries the electronic Sp(ππ*) states of the isomers can be characterized through the corresponding configurations. Taking into account these results an interpretation of the electronic absorption spectra is presented. The conclusions with respect to the chromophoric system are generalized for this class of compounds.
Zur Kenntnis der katalytischen Dimerisation von Acrylsäurederivaten mit Hilfe von Palladiumkomplexen. IV. Zur Dimerisation von Methyl‐methacrylat
Authors: Oehme G. 
Published: December 2004

On the Catalytic Dimerization of Acrylic Acid Derivatives by Palladium Complexes. IV. The Dimerization of Methyl Methacrylate.Methyl methacrylate has been dimerized to a mixture of 2.5‐di(methoxycarbonyl)‐hex‐1‐ene(1) and (E)‐2.5‐di(methoxycarbonyl)‐hex‐2‐ene (2) by catalytic systems containing dichlorobis (nitrile)‐palladium (II) complexes and silver tetrafluoroborate, Codimerization experiments with methyl acrylate show a lower reactivity of methyl methacrylate. Oxidative addition of ß‐chloro methyl methacrylate to tetrakis (triphenylphosphine) palladium (O) gave ß‐polladio methyl methacrylates (8, 9) suitable for model investigations of the catalytic reaction. A proposal is given for a mechanism via pd(IV) intermediates.
Massenspektrometrische Fragmentierung von 4‐substituierten 5‐Hydroxynaphth[2,1‐d]1,3‐oxathiol‐2‐onen
Authors: Lepom P. , Herzschuh R. , Wilde H. , Mann G. 
Published: December 2004

Mass Spectrometric Fragmentation of 4‐Substituted 5‐Hydroxynaphth[2,1‐d]1,3‐oxathiol‐2‐onesThe mass spectra of 5‐hydroxynaphth[2,1‐d]1,3‐oxathiol‐2‐ones 1a‐1x have been studied. They show characteristic fragmentations with participation of neighbouring groups. Investigations of isotopically labelled 4‐alkyl and 4‐acyl derivatives give evidence for the formation of cyclic ionic structures.
Zur Cyanethylierung von Hydrochinazolinonen
Authors: Bischoff Christian , Schröder Edith , Gründemann Egon 
Published: December 2004

Cyanoethylation of HydroquinazolinonesBy the reaction of acrylonitrile with octahydroquinazolinone‐spirocyclohexane (1), cyanoethyl‐octahydroquinazolinone‐spirocyclohexane (2) is formed. Compound 2 and hydrogen‐peroxide yield 5a‐cyanoethyl‐5‐oxo‐perhydro‐oxaziridino[3,2‐j]‐quinazolin‐2‐spirocyclohexane (5). 2‐Phenyl‐octahydroquinazolinone (7) and acrylonitrile form 3,5a‐biscyanoethyl‐2‐phenyl‐octahydroquinazolinone‐(4) (8). Compound 8 and hydrogenperoxide yield 3‐phenyl‐4,5a‐biscyanoethyl‐4‐oxoperhydro‐oxaziridino[3,2‐j]‐quinazoline (9). Compound 9 rearranges with ferrous sulphate to 3,4a‐bis‐cyanoethyl‐4‐oxo‐8a‐hydroxy‐2‐phenyl‐octahydro‐quinazoline (10).
1H‐kernmagnetische Resonanzspektren der Phenylfulgide
Authors: Ilge H.‐D. , Schütz H. 
Published: December 2004

1H‐Nuclear Magnetic Resonance Spectra of PhenylfulgidesThe 1H‐chemical shifts are determined in a series of phenylfulgides in order to investigate the steric influences of substituents. The magnetic anisotropy of the carbonyl and the phenyl groups is used for a qualitative discussion of the steric effects introducing different substituents in the fulgide framework. The benzene induced solvent shift supports the conclusions about the bond angle alterations between the different compounds.
Reversible photoisomerizations of sulfonephthalein indicator dyes. III. Kinetic Analysis of the Intermediate Sultone Formation
Authors: Grummt U.‐W. 
Published: December 2004

AbstractA detailed kinetic analysis is presented of the transient sultone (A2) formation which proceeds thermally from a photogenerated intermediate species after flash excitation of bromo thymol blue and bromo xylenol blue in the presence of quinoline, pyridine and 4‐methyl pyridine in toluene solution. The sultone ring cleavage is a bimolecular reaction with the base resulting in a hydrogen‐bridged molecular complex (A1) which equilibrates consecutively with the most stable rotamer of the ion pair (A3). The rate constants for the latter reaction are controlled essentially by conformational changes rather than by the proper proton transfer.
Spin‐Trapping von Radikalen bei der Zersetzung aromatischer Diazoniumsalze mittels Ultraschall
Authors: Rehorek Detlef , Janzen Edward G. 
Published: December 2004

Spin Trapping of Radicals Formed during the Decomposition of Aromatic Diazonium Salts by UltrasoundThe decomposition of aromatic diazonium compounds ArN2⊕X⊖ (Ar = phenyl, 2,5‐diethoxy‐4‐(N‐morpholino)phenyl; X = BF4, PF6, B(C6H5)4, SCN, OCN,N3; 1a, 1c–f, 2b–f) by ultrasonic waves has been studied by e.s.r. The spin trapping technique has been shown to be a suitable method for the detection of free radical intermediates.
10β‐Chlor‐östra‐1,4‐diene als Zwischenprodukte bei der Einführung einer 9(11)‐Doppelbindung in Östra‐1,3,5(10)‐triene
Authors: Kasch H. , Ponsold K. 
Published: December 2004

10β;‐Chloro‐estra‐1,4‐dienes as Intermediates of the Introduction of a 9(11)‐Double Bond in Estra‐1,3,5(10)‐trienesThe synthesis of 9(11)‐didehydro‐estra‐1,3,5(10)‐trienes 5 starting from estra‐1,3,5(10)‐trienes 1 is described. 1 can be transformed into the ketals 2 and 3 by means of isocyanuric acid chloride and an alcohol such as methanol or ethylene glycol in the absence of moisture.The ketals 2 and 3 are sensitive against hydrolysis and react in the presence of water and traces of acid under formation of chlorodienone 4. Dehydrochlorination of 2, 3 and 4 with potassium‐tert.‐butylate in dimethylsulfoxide gives the 9(11)‐didehydro compounds 5. The reaction mechanism of the electrophilic addition of positive chlorine and alcohol to the aromatic A‐ring of 1 is discussed.
Reaktionen einer technischen Butenfraktion mit Trichloracetaldehyd
Authors: Biering H. , Voigtländer R. , Matschiner H. 
Published: December 2004

Reactions of a Technical Fraction of Butene with TrichloroacetaldehydeIn pyrolysis plants for gasoline production a C4‐fraction is formed containing isobutene, but‐1‐ene and but‐2‐ene as main products. The reactive separation of this fraction represents an industrial problem. One way to solve this problem is the reaction of trichloroacetaldehyde with these components to form addition products. The favoured reaction is the formation of 1,1,1‐trichloro‐4‐methyl‐pent‐4‐en‐2‐ol (1) and 1,1,1‐trichloro‐4‐methyl‐pent‐3‐en‐2‐ol (2) from iso‐butene. The other isomers react very slowly. The influence of different reaction parameters was investigated to find a method for a reactive separation of the C4‐fraction.
Elektrochemische Carboxylierung von Cinnamoyl‐1,1‐bis(alkylthio)‐ethylenen
Authors: Matschiner H. , Rüttinger H. H. , Austen S. 
Published: December 2004

Electrochemical Carboxylation of Cinnamoyl‐1,1‐bis(alkylthio)ethylenesCinnamoyl‐1,1‐bis(alkylthio)ethylenes (1a–1h) are reduced electrochemically in the presence of carbondioxide in aprotic media. The attack of CO2 takes place either in 1‐ or 5‐position of cinnamoyl‐1, 1‐bis(alkylthio)ethylenes (1a–1h) depending on the nature of the aryl substituents. If CO2 reacts in position 1 carbonic acids 3 are obtained, reaction of carbondioxide in 5‐ position leads to the acids 2. The effects of different aryl substituents on the halfwave potentials and the preparative electrolyses have been investigated.
Prostaglandins and prostaglandin intermediates. XIV. Synthesis of rac‐9α, 11α, 13α‐trihydroxy‐ and rac‐9α, 11α, 13β‐Trihydroxy‐5(Z)‐prosten‐15‐ynoic Acid
Authors: Mahrwald R. , Schick H. , Schwarz S. 
Published: December 2004

AbstractAttempts to rearrange a β‐hydroxy‐alkyne with a secondary hydroxy group into an α,β‐unsaturated ketone failed in the case of a potential prostaglandin intermediate. However, it was possible to convert this intermediate into 13‐hydroxy‐5(Z)‐prosten‐15‐ynoic acids, which are interesting prostaglandin analogues with a modified alkyl side chain.
13C‐ und 15N‐NMR‐spektroskopische Untersuchungen an Push‐pull‐butadienen
Authors: Michalik M. , Peseke K. , Radeglia R. 
Published: December 2004

13C and 15N N.M.R. Spectroscopic Investigations on Push‐pull Butadienes13C and 15N n.m.r. spectroscopic investigations show the push‐pull‐character of the investigated butadienes 1 and 2. Linear correlations exist between 13C and 15N chemical shifts and σp‐constants of substituents on the phenyl ring, and between 13C chemical shifts and ΔG≠ values of the C1C2 rotation process in 1, respectively.
EPR‐Untersuchungen kernchlorierter 4‐Dimethylaminophenylkationen
Authors: Fanghänel E. , Kriwanek J. , Mörke W. 
Published: December 2004

EPR Investigations of Ring Chlorinated 4‐DimethylaminophenylcationsThe influence of the position and the number of chlorine atoms in the ring of 4‐dimethylaminophenylcations on the zero‐field‐splitting(zfs) parameter Dis investigated. It was found that the π‐donor ability of the chlorine atom(s) ind 2(6)‐position(s) increases the zfs parameter D. In the case of 3(5)‐substitution the value of D decreases because of the steric hindrance of the dimethylamino‐group.
Action of grignard reagents and amines on some N‐(Arylmethyleneamino)phthalimides
Authors: Ismail M. Fekry , El‐Bassiouny F. A. , Enayat E. I. , Kaddah A. M. , Younes H. A. 
Published: December 2004

AbstractN‐(Arylmethyleneamino)phthalimides (2a–c) carrying an o‐substituent in the aryl group were prepared by the reaction of N‐aminophthalimide with o‐substituted benzaldehydes. The reaction of these compounds with Grignard reagents proceeded either by normal addition to one of the carbonyl groups to give 3a–c or by addition and cleavage to give 4‐arylphthalaz‐1‐ones 5a–c. The steric effect exhibited by either the Grignard reagent or the N‐arylmethylene compound was studied. The reaction of N‐furfurylideneaminophthalimide (2d) with Grignard reagents was also investigated. N‐(Arylmethyleneamino)phthalimides reacted with primary amines to give N,N′‐dialkylphthalamides (7a and b) while the reaction with secondary amines gave (8a and b).
IR‐spektroskopische Untersuchung zur Lösungsmittelwechselwirkung von 1‐Benzylidenpyrazolid‐3‐on‐betainen
Authors: Siegmund Manfred , von Löwis Michael , Geissler Gunther , Menz Irina 
Published: December 2004

Investigation of Solvent‐Solute Interactions of 1‐Benzylidenepyrazolidone (3) ‐betaines by I.R. SpectroscopyThe infrared spectra of eight 1‐benzylidenepyrazolidone(3)‐betaines (1–7 and 3 m) have been measured in 22 solvents of different polarity. The carbonyl band of these compounds indicates specific and non‐specific solvent‐solute interactions, which are qualitatively characterized by the electrophilic properties of the solvent (E‐value, acceptor number AN). Intermolecular hydrogen bonds have been detected in protic solvents. The thermodynamic quantities of the associate equilibrium, K,ΔRH,ΔRS were determined in chloroform and deuterochloroform, respectively, by the i.r. intensity method.
Elektrochemische Oxydation organischer Verbindungen in Fluorsulfonsäure. X. Effekt der Aciditätserhöhung auf das anodische Verhalten einiger aromatischer Verbindungen im System HSO3FSbF5
Authors: Rudenko A. P. , Sarubin M. Ja. , Awerjanow S. F. , Pragst F. 
Published: December 2004

Electrochemical Oxidation of Organic Compounds in Fluorsulfuric Acid. X. Effect of the Increase in Acidity on the Anodic Behavior of Some Aromatic Compounds in the HSO3FSbF5‐SystemThe effect of the acidity on the anodic behavior of some aromatic nitrils, nitro compounds, amines, sulfonyl fluorides, carbonyl compounds, hydrocarbons, benzylic acetates and methoxy compounds is investigated by cyclic voltammetry in HSO3F and HSO3FSbF5 (molecular ratio 15:1 and 3:1) at −76°C and in some cases in HSO3FSbF5 (1:1) at −40°C. With increasing content of SbF5 in most cases a positive shift of the anodic half‐peak potentials Δ Ep/2 is found, which depends on the type and on the strength of the interaction with the superacidic solvent. Δ Ep/2 increases from the protonated functional groups in the series NH3⊕ (0.00 V), CN (0.05–0.10 V), SO2F (0.10–0.20 V), COR (0.20–0.40 V), NO2 (0.30–0.60 V), OCH3 (>0.8 V) to benzoylium ions (0.45–0.60 V), benzyl cations (0.60–0.80 V) and arenium ions (1.10–1.30 V). Besides, the anodic behavior depends to a large extent on the deprotonation rate of the substrate, which occurs precedingly to, simultaneously with or subsequent to the electron transfer.
Blitzlichtspektroskopische Untersuchungen an 1‐Phenylazo‐2‐naphtholen
Authors: Grummt U.‐W. , Epperlein J. 
Published: December 2004

Flash Spectroscopic Investigations on 1‐Phenylazo‐2‐Naphthols1‐(p‐R‐Phenylazo)‐2‐naphthols with R = NMe2, OH, OCH3, CH3, H, F, Br, COCH2, NO2, CN show reversible bleaching over the entire visible and near u.v. spectral region upon flash photolysis in ethanol and toluene. It is proposed to interpret this by photochemical formation of the corresponding cis‐azo compound. The thermal relaxation is not an elementary reaction but it involves intermediate tautomerisation. A V‐shaped Hammett correlation is found for the rate constants of the thermal relaxation.
Strukturaufklärung von ausgewählten nitro‐ und sulfonsäuresubstituierten 1,2‐Naphthochinon‐2‐diaziden
Authors: Gey E. , Radeglia R. , Elger J. , Brandtstädter H. , Geissler H. , Hauser A. 
Published: December 2004

Structure Determination of Selected Nitro and Sulfonic Acid Substituted 1,2‐Naphthoquinone‐2‐diazidesSelected nitro derivatives of 1,2‐naphtoquinone‐2‐diazide 2 and 5 have been synthesized, the position of the NO2‐group has been unambigously determined by means of 1H and 13C n.m.r. spectroscopy, and the structure of these compounds has been comprehensively determined in relation to unsubstituted 1 and sulfonic acid substituted derivatives 3, 3a, 4 and 4a.Furthermore, the spectroscopical behaviour, especially in the uv/vis region, was examined in correlation to quantum chemical calculations.
Quantenchemische Untersuchungen zur Farbe und Stereodynamik von acyclischen Azinen. XV. Zum strukturellen Aspekt des Photochromie‐Effektes
Authors: Gustav K. , Vettermann S. 
Published: December 2004

Quantum Chemical Studies on Colour and Stereodynamics of Acyclic Azines. XV. On the Structural Aspect of the Photochromic EffectFor the longest‐wavelength colour‐determining electronic transition of selected arylsubstituted acyclic azines the curvature of λ=λ(θcc) has been adapted by means of polynomic and trigonometric functions. On this basis it is possible to discuss the structural aspect of the photochromic and aphotochromic behaviour being observed due to the (E, Z) isomerization.