Rosa zalana Wiesb. (Rosaceae) u hrvatskoj flori

This communication gives the information that Rosa zalana belongs to the flora of Croatia. This species was discovered as far back as 1884 by Ljudevit Vukotinović in the neighborhood of Varaždinske Toplice. This is the southernmost locality of this Central European species.U radu se objavljuje podatak da je vrsta Rosa zalana pripadnik hrvatske flore. Otkrio ju je još davne 1884. godine Ljudevit Vukotinović u okolici Varaždinskih Toplica. To je ujedno i najjužnije nalazište navedene srednjoeuropske vrste

Rosa zalana Wiesb. (Rosaceae) u hrvatskoj flori

This communication gives the information that Rosa zalana belongs to the flora of Croatia. This species was discovered as far back as 1884 by Ljudevit Vukotinović in the neighborhood of Varaždinske Toplice. This is the southernmost locality of this Central European species.U radu se objavljuje podatak da je vrsta Rosa zalana pripadnik hrvatske flore. Otkrio ju je još davne 1884. godine Ljudevit Vukotinović u okolici Varaždinskih Toplica. To je ujedno i najjužnije nalazište navedene srednjoeuropske vrste

Graph Theory and Molecular Orbitals. IV. Further Application of Sachs Formula

In the present note we would like to report a further application1 of the Sachs formula2 to conjugated hydrocarbons

Graph Theory and Molecular Orbitals. VIII. Kekule Structures and Permutations

The relation between Kekule structures and permutations is discussed. It is shown that Kekule structures are permutations and that their number in alternant hydrocarbons is equal to the square root of the total number of permutations contained in the molecular graph. As simple special cases of this result the Dewar-Longuet- Higgins equation2 and the relation between the permanent · of the adjacency matrix and the number of Kekule structures3 are obtained. Generalizations for nonalternant hydrocarbons are also given

Graph Theory and Molecular Orbitals. XVI. on π-Electron Charge Distribution

An integral formula is derived exhibiting the dependence of the π-electron charge density (in the framework of Huckel theory) on the coefficients of the characteristic polynomial of the molecular graph and one of its subgraphs. Several simple consequences of this formula are demostrated

Graph Theory and Molecular Orbitals. XIII. On the Stability of Annelated Tropylium Cations

A topological approach is used for studying the origin of differences in stabilities of benzoannelaied, and furo- and/or thieno.annelated tropylium cations. Recently available experimental data could be thus rationalized and the pKR + values of yet unknown compounds in these series prediicted

On the Parity of Kekule Structures

The notion of the parity of Kekule structures is discussed. A necessary and sufficient condition for the separability of Kekule structures into odd and even is given. It is also shown that there are po~sible certain molecules with a nori-alternant topology, the Kekule structures of which cannot be separated. The synthesis of such compounds would be of interest

Graph Theory and Molecular Orbitals. IV. Further Application of Sachs Formula

In the present note we would like to report a further application1 of the Sachs formula2 to conjugated hydrocarbons

Simple Topological Formula for Dewar Resonance Energies of Benzenoid Molecules

Dewar and co-workers1 have reinvestLgated the classical concept of resonance energy, CRE, and by making use of a polyene reference structUJI\u27e instead of the ethylene reference structure they were able to obtain giood agreement between the SCF pi-MO calculations ·and experianerutal findings for both benzenoid and non-benzenoid molecules. This new concept, later named2 »Dewar resonance energy«, was used with equal success within the framework o.f Ruckel theorry3• Extensive tables of DRE value of benzenoid hydrocarbons have been published3