Cr. Simionescu

Bifunctional initiators—V. Synthesis and characterization of 4,4′-azo-bis-(4-cyanovaleryl)-bis-(m-chlorobenzoyl) diperoxide

Abstract A new azoperoxide bifunctional initiator was synthesized by the condensation of 4,4′-azo-bis-(4-cyanovaleric) acid chloride with m -chloroperbenzoic acid. This condensation was also carried out starting from the 4,4′-azo-bis-(4-cyanovaleric) acid by activation with dicyclohexylcarbodiimide. The initiator structure was confirmed by i.r. and NMR spectroscopy. Kinetic measurements on thermolysis and photolysis confirm the sequential decomposition of this compound.

Monosubstituted derivatives of ferrocene. Ferrocene-containing penicillins and cephalosporins

Abstract The paper discusses the synthesis and properties of five new penicillins and five new cephalosporins with ferrocene, obtained through acylation (the mixed-anhydride technique) of 6-aminopenicillanic and 7-aminocephalosporanic acid with 1,1′-bis[1-carboxymethyl)thioalkyl]ferrocene and 1,1′-bis[1-(carboxymethyl)thio-1-phenylmethyl]ferrocene. The β-lactamic derivatives obtained have been characterized as natrium salts, through spectroscopic (IR and UV) analyses, as well as through TLC. These products show good activity against Gram-positive bacteria, comparable to that of amoxicillin, carbenicillin and cephalotin, while their activity towards Gram-negative bacteria was found to be insignificant.

Mono- and heterodi-substituted derivatives of ferrocene; β-Lactamic antibiotics

Abstract The ferrocenylsulphonamidopenicillanic (I), -cephalosporanic (II) and -deacetoxycephalosporanic (III) acids and 1,1′-ferrocenylendisulphonamidopenicillanic (IV), -cephalosporanic (V) and -deacetoxycephalosporanic (VI) acids were synthesized and the optimum conditions determined. The products obtained were characterized as their sodium salts by thin-layer chromatography and IR spectral measurements. Compounds II, IV, V and VI show activity towards Gram-positive germs.

Heterodisubstituted ferrocene derivatives; β-lactamic antibiotics

Abstract The influence of the ferrocenyl residue on the antimicrobial activity of β-lactamic antibiotics was studied and the reaction conditions fixed for the formation of 1,1′-ferrocenyldicarboxamidopenicillanic (IX) and 1,1′-ferrocenyldicarboxamidocephalosporanic acid (Xa and Xb). The products were characterized as both acids IX and sodium salts X by IR and UV spectra as well as by thin-layer chromatography. The compounds IX and X show antimicrobial activity towards some Gram positive germs.

Metallocene monomers and polymers. Ferrocenyl and ferrocenylene derivatives

Abstract The synthesis and study of some polyenes, polýiminoimides and Schiff polybases with ferrocene obtained by either polymerization or polycondensation are reported. The following monomers were used: ethynylferrocene, 1-chloro-1′-ethynyl-ferrocene, α-chloro-β-formyl- p -ferrocenylstyrene, p -ferrocenylphenylacetylene, p -ferrocenylacetophenone, 1,1′-diacetylferrocene and 1,1′-bis[β-(2-furyl)acryloyl]ferrocene which were characterized by spectral and thermodifferential analyses and Huckel MO calculations. The polymerization was performed in the presence of benzoyl and lauroyl peroxides, triisopropylboron and complex catalysts of [P(C 6 H 5 ) 3 ] 2 NiX 2 type. The ferrocene derivatives were polycondensed with biuret, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl thioether, 4,4′-diamino-2,2′-dinitrodiphenyl disulphide in the presence of metallic salts and p -toluene sulphonic acid as catalysts. Polymers with either linear or tridimensional structure showing good thermal stability and semiconducting properties have been obtained. Some polymers show catalytical activity in the polymerization of chloroformylated vinylic derivatives.

Mechanochemically initiated polymerizations—5. Polymerization by vibratory milling of acrylamide and methacrylamide

Abstract Mechanochemical polymerization by vibratory milling of acrylamide and methacrylamide is discussed. The influences of duration, nature of medium and temperature are examined. The polymers are characterized by elemental analysis, i.r.-spectroscopy. X-ray and by determination of some properties. An anion-radical mechanism is proposed.

Investigations on electric properties of polymers—V: On the a.c. conductivity of polyphenylacetylenes

Abstract The electric conductivity of polyphenylacetylene with various physical and isomeric structures (cis-cisoidal, cis-transoidal and trans-cisoidal) was investigated over the frequency and temperature ranges of 10-105 Hz and 273–347 K, respectively. The transient currents from polyphenylacetylene having cis-cisoidal structure were also studied at 293 K. It was found that a.c. conductivity of cis-cisoidal polymer can be explained in terms of a hopping mechanism. The type of mechanism (classical or quantum) depends both on frequency and temperature. At temperatures

Investigations on electric properties of polymers—III. d.c. and a.c. conductivity of polyphenylacetylene films

Abstract d.c. and a.c. Conductivity measurements were made on films of polyphenylacetylene(PPA) having cis-transoidal(c-t) and trans-cisoidal(t-c) isomeric structures. PPAc-t crystallizes from solution in benzene, while PPAt-c remains unchanged (amorphous). Films of both polymers have d.c. and a.c. conductivities higher than those of pellets. The d.c. conductivity-temperature curve of the PPAc-t film consists of four parts (I, II, III and IV) of different slopes. Comparing the activation energies of d.c. conductivity with optical threshold energy (in solid state), the hopping mechanism (over the I, II and IV parts) and band-tunnelling mechanism (over part III) were suggested. The PPAt-c film shows the hopping mechanism. The a.c. conductivity data were interpreted in terms of either simple quantum hopping or a simple classical hopping mechanism depending on frequency and temperature range.

Ferrocene polymers The polycondensation of p-ferrocenylacetophenone☆

Abstract The polycondensation of p -ferrocenylacetophenone in the presence of some metallic salts has been studied, and a scale of the catalytic activity of the metallic salts has been determined. The influence of the ferrocenyl residue on the carbonyl group in p -ferrocenylacetophenone and on the electrophysical properties is considered by applying Huckel MO calculations. The monomers synthesised show semiconducting properties.

Ferrocene polymers. Synthesis and thermal polymerization of α-chloro-β-formyl-p-ferrocenylstyrene

The synthesis and thermal polymerization of a new chloroformylated vinyl derivative containing a ferrocenyl residue are reported. The reactivity of α-chloro-β-formyl-p-ferrocenylstyrene in the polymerization reaction is discussed in the light of the experiment results and data obtained from molecular orbital calculations using the Huckel approximation.