Showing papers in "ChemInform in 1973"

An algebraic model of constitutional chemistry as a basis for chemical computer programs

Abstract: The presently available chemical computer programs are discussed, as well as the fact that a mathematical theory of constitutional chemistry is needed as a basis for substantial progress in computer assisted solutions to chemical problems. The representation of EM 1) and their interconversions by be-matrices 1) and reaction matrices leads to the logical structure of the FIEM 1) and is representative for constitutional chemistry. A mathematical theory of the FIEM is stated, which can serve as the foundation of a new type of matrix-fitting computer programs for establishing constitutional relations such as synthetic design, the elucidation of reaction mechanisms, and bio-synthetic pathways, as well as the analysis of mass spectra.

Interaction of hardened cement paste and water

Abstract: ADSORPTION OF WATER VAPOR ON A CLEAN SURFACE CHANGES THE SURFACE FREE ENERGY. IT IS SHOWN THAT, USING THE GRIFFITH CRITERION, THE CHANGE OF STRENGTH AS FUNCTION OF MOISTURE CONTENT CAN BE EXPLAINED BY ASSUMING A CHANGE OF SURFACE ENERGY. IN COLLOIDAL PARTICLES SURFACE ENERGY CREATES CONSIDERABLE HYDROSTATIC PRESSURE. A CHANGE IN ELASTIC MODULUS AND SHRINKAGE AS WELL AS SWELLING CAN BE RELATED TO A CHANGE IN HYDROSTATIC PRESSURE IN INDIVIDUAL GEL PARTICLES. CREEP IS AFFECTED PRIMARILY AT THE HIGHER RELATIVE HUMIDITIES. THE MAIN PARAMETERS OF A PROPOSED MODEL FOR HYDRATED PORTLAND CEMENT ARE SURFACE FREE ENERGY AND DISJOINING PRESSURE. ON THIS BASIS THE MECHANICAL BEHAVIOR OF HARDENED CEMENT PASTE IS DISCUSSED. A PHASE TRANSITION OF ADSORBED WATER NEAR 90 DEGREES C IS DISCUSSED. THE INFLUENCE OF THIS EFFECT ON THE MECHANICAL BEHAVIOR OF HARDENED CEMENT PASTE CAN BE UNDERSTOOD WHEN A CHANGE IN INTERFACIAL ENERGY IS TAKEN INTO CONSIDERATION. /AUTHOR/

Manganese schiff′s base complexes part 1, synthesis and spectroscopy of some anion complexes of (4-sec-butylsalicylaldehydeethylenediiminato)manganese(iii)

Abstract: A series of new five-coordinate complexes of the type [Mn(BuSalen) X ] where BuSalen is the tetradentate Schiff's base 4-sec-butylsalicylaldehydeethylenediimine and X equals F − , Cl − , Br − , I − , N 3 − , NCS − , OCN − , NO 2 − and C 2 H 3 O 2 − have been synthesized and characterized. I.R. and electronic absorption spectra have been measured and tentative band assignments made. The room temperature magnetic susceptibility measurements on the complexes in chloroform and dimethysulfoxide solution yield magnetic moments of ∼4·9 B.M., i.e. the expected spin only value for high spin Mn(III). Conversely, magnetic moments of the solid complexes range from 4·2 to 5·0 B.M. depending on the anion. It is suggested that the lowering of the moment is due to the formation of dimers with antiferromagnetic interaction, in the solid.

Metabolic conversion of benzo(a)pyrene by syrian hamster liver microsomes and binding of metabolites of deoxyribonucleic acid

Abstract: Aus Benzo(a)pyren (Ia) werden die Metaboliten (Ib), (Ic), (II), (III) sowie (IVa) und (IVb) erhalten und in ihrer Struktur bestatigt.

Synthesis with n‐protected 2‐lithioindoles

Abstract: 1-Substituierte Indole (I) werden mit Butyllithium behandelt und nach Hydrolyse das Ausmas einer 2-Substitution uber Deuterierungsreaktionen ermittelt.

Diaziridines part 2, the addition of diaziridines to electrophilic acetylenes

Abstract: Diaziridine (I) reagieren mit Dibenzoylacetylen (II) unter Ringspaltung zu den Butendionen (III), die unabhangig aus den Hydrazonen (IV) erhalten werden.

Rates of intramolecular Diels-Alder reactions of pentadienylacrylamides

Abstract: α-Phenyl-zimtaldehyd (I) liefert nach bekannten Verfahren den homologen Aldehyd (II), aus dem uber eine Boranatreduktion der Imine die Amine (III) erhalten werden konnen.