Oskar E. Polansky

Band structure of nonclassical polymers

It is shown that fully conjugated alternant nonclassical polymers are comparatively stable systems as a result of the considerable delocalisation energy.The energy characteristics of the polymers are strongly determined by the electron spin distribution of the degenerate nonbonding molecular orbitals; the full spin configuration,S>0, is favoured. The spin densities depend on the electron correlation and alternate; this corresponds to a ferrimagnetic state of the polymer at 0°K.

Oxy- und Aminomethylenmeldrumsäuren

Die Darstellung von Oxy- und Aminomethylenmeldrumsauren wird beschrieben, ihre IR- und NMR-Spektren angegeben und aufgrund der HMO-π-Elektronenstrukturen interpretiert. Ein qualitativer Zusammenhang der Streckschwingungsfrequenzen der Mehrfachbindungen des Acylalringes und der entsprechenden π-Bindungsordnungen und der Ladung des Acylalringes wird beobachtet. Das Umsetzungsprodukt aus Hydroxymethylenmeldrumsaure und Brady-Reagens wird als 2,4-Dinitrophenylhydrazyl-methylenmeldrumsaure erkannt.

Structure and properties of non-classical polymers. II: Band structure and spin densities

Theoretical investigation of the band structure of three types of nonclassical polymers, namely alternant (one- and two-dimensional), nonalternant and heteroatomic, are carried out. Although polyradicals, these polymers have a considerable delocalization energy which may determine their relative stability.The spin-density distribution of the alternant type of non-classical polymers corresponds to a ferrimagnetic ground state at 0 K.The non-classical polymers represent a new class of organic systems as their band structure and magnetic properties essentially differ from those of common polymers.

Topological effects on mo energies

Abstract By different linkages between bi- or multi-valent molecular partial structures, pairs of isomers are generated which are denoted by ∫ and ⊥, e.g. o -(∫) and p -benzoquinodi-methane (⊥). Using analytical methods, it is shown that the MO patterns of ∫ and ⊥ are generally related to one another so that in any interval bounded by two eigenvalues of ∫, there are alternately two and zero eigenvalues of ⊥. Furthermore, unifying relationships concerning the HOMO-LUMO separation of the systems are obtained. All these findings are equally valid for the π- and the σ-MOs of alternant and non-alternant, and benzoid and non-benzoid systems. The analytically derived conclusions are verified by comparison with experimental data and ab initio calculations.

An extension of the Coulson-Rushbrooke theorem

Abstract It is shown that the Coulson-Rushbrooke theorem for odd alternant hydrocarbons and polymers can be extended to some classes of non-classical (non-Kekule) systems containing heteroatoms. The extension is only applicable to non-bonding molecular orbitals. The band structure of such polymers is analogous to that of odd alternant non-classical polymers, whose ground state is characterized by maximum spin multiplicity.

Application of distance and similarity measures. The comparison of molecular electronic structures in arbitrary electronic states

Abstract The mathematical concepts of distance and similarity measures are introduced into quantum chemistry to aid in the comparison of molecular electronic structures in arbitrary electronic states. Some partial measures are defined to help in estimating the similarity between molecular subunits. The distance measure is constructed using the elements of the chargebond-order matrix. Some fields of possible applications are mentioned and a new index of analogy is defined. This approach is applicable, in principle, to any LCAO method.

NMR-Spektren einiger Benzylidenbarbitursäurederivate

The NMR-Spectra of substituted benzylidene barbituric acids, benzylidene dimethylbarbituric acids and some 1,4-and 1,3-cycloaddition products are reported. The signals of the olefinic protons and the N−CH3-signals depend on the conformation of the compounds. The NMR-Spectra of the anions are also given.

Variational approach to the linear Jahn-Teller effect E ⊗ ϵ

Abstract A variational approach is presented for the ground state of the linear Jahn-Teller effect E ⊗ ϵ. Using the variational wavefunctions thus obtained we have also calculated Hams reduction factor p . Our results for the energy and the reduction factor are in reasonable agreement with numerical solutions.

Umsetzungen einiger Ketimine mit Meldrumsäure, Dimedon, Indandion-(1,3) und Perinaphthindandion-(1,3)

Es werden siebzehn neue, durch Kondensation von Meldrumsaure, Dimedon, Indandion-(1,3) und Perinaphthindandion-(1,3) mit Alkyl-aryl-bzw. Diarylketiminen hergestellte Verbindungen beschrieben.

Über Benzazole, 2. Mitt.: Die UV-Spektren der Benzazole

Es wird gezeigt, das den Spektren des Indazols und seiner Derivate drei Bandensysteme zugeordnet werden konnen. Der Einflus von Substituenten wird diskutiert und die zusatzliche langwellige Absorption der 2-Acetylindazole einem n-π*-Uber-gang zugeschrieben. Diese Bandensysteme treten analog auch bei anderen Benzazolen auf.