Search

Cyclic peroxides as initiators for the radical polymerization of methyl methacrylate were proposed. The initial rates, initiation rates, and effective activation energies of polymerization initiated by cyclic peroxides and cyclic peroxide-1-pyridyl-2-ferrocene systems were determined. The radical yields to the volume upon the thermal decomposition of cyclic peroxides and their catalytic decomposition in the presence of 1-pyridyl-2-ferrocene were determined. In combination with 1-pyridyl-2-ferrocene cyclic peroxides form efficient initiating systems favoring an increase in the polymerization rate, a decrease in the molecular weights, and an increase in syndiotacticity of the synthesized poly(methyl methacrylate). © 2013 Springer Science+Business Media New York.

Radical polymerization of methyl methacrylate initiated by the benzoyl peroxide — macrobicyclic bis-ferrocenylboron-capped iron(ii) tris-1,2-cyclohexanedione dioximate system was studied. The ferrocenyl-containing macrobicyclic complex and benzoyl peroxide forms an efficient initiating system that allows one to perform the polymerization process at a high rate with substantially reduced amounts of the initiator and the metal complex component at 30–75 °C and to influence the molecular-weight characteristics of poly(methyl methacrylate) produced.

A series of ferrocenylboron-capped tris-dioximate iron(ii) clathrochelates was synthesized by the template condensation of three molecules of dimethylglyoxime (H2Dm), cyclohexanedione 1,2-dioxime (H2Nx), or cyclooctanedione 1,2-dioxime (H2Ox) and two molecules of ferrocenylboronic acid (FcB(OH)2) on the Fe2+ ion matrix. The yields of the clathrochelate derivatives of alicyclic dioximes were substantially higher than that of their acyclic analog, because the molecules of alicyclic H2Nx and H2Ox α-dioximes have the s-cis-configuration suitable for complex formation, whereas the H2Dm molecules in solution have the s-trans-configuration. The synthesized compounds were characterized using elemental analysis, IR and UV-Vis spectroscopies, MALDI-TOF mass spectrometry, 1H and 13C{1H} NMR and 57Fe Mossbauer spectroscopies, and X-ray diffraction analysis. The crystal of FeDm3(BFc)2·CHCl3 contains two types of crystallographically nonequivalent clathrochelate molecules. The intermolecular contacts C-H⋯Cp formed by the ferrocenyl fragments and cyclooctane carbocycles and the interactions Cp-H⋯O were observed in the crystal of FeOx3(BFc)2. The structural lability of the cyclooctane substituents allows the FeOx3(BFc)2 molecules to arrange by the “bump-into-hollow” mode because of attractive H⋯H interactions between the ribbed substituents of the neighboring molecules. The geometry of the ferrocenylborate iron(ii) clathrochelates is intermediate between a trigonal prism and a trigonal antiprism.

The direct template macrocyclization of 2,3-butanedione monooxime hydrazone (HDXO) with ferrocenylboronic acid on the iron(ii) ion matrix afforded the ferrocenylboron-capped semiclathrochelate iron(ii) oximehydrazonate. The H+ ion-catalyzed macrocyclization of this precursor with an excess of triethyl orthoformate gave the clathrochelate complex with syn,syn,syn-orientation of the ethoxy substituents relative to the 1,3,5-triazacyclohexane ring. The complexes synthesized were characterized using elemental analysis, IR and UV—Vis spectroscopies, MALDI-TOF mass spectrometry, 1H and 13C{1H} NMR, 57Fe Mossbauer spectroscopies, and X-ray diffraction analysis.