The antibiotic ciprofloxacin (CIP) was covalently attached to the chain end of poly(2-methyloxazoline) (PMOx), poly(2-ethyloxazoline) (PEtOx), and polyethylene glycol (PEG), and the antimicrobial activity of these conjugates was tested for Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, and Kleisella pneumoniae. Chemical structures of the conjugates were proven by (1)H NMR and electron spray ionization mass spectrometry. The direct coupling of PMOx and CIP resulted in low antimicrobial activity. The coupling via a spacer afforded molecular weight dependent activity with a molar minimal inhibitory concentration that is even higher than that of the pristine CIP. The antimicrobial activity of the conjugates increases in the order of PMOx < PEtOx < PEG. Conjugation of CIP and a quaternary ammonium compound via PMOx did not result in higher activity, indicating no satellite group or synergistic effect of the different biocidal end groups.

The coordination contacts to the metal lithium allow the desymmetrisation of dimethoxysilanes by substitution with organolithiums under high kinetic stereocontrol.

The title compounds, C13H18O3Si (1) and C18H20O3Si (2), represent functionalizable dihydrofuranylsilanes, which permit substitution by a variety of nucleophiles. The crystal structures of 1 and 2 display weak intermolecular C—H...O hydrogen-bonding interactions (quantified by Hirshfeld surface analysis), leading to a two-dimensional supramolecular network for 1 and a one-dimensional supramolecular network for 2. The crystal structures of 1 and 2 were refined both on the basis of the independent atom model (IAM) and the Hirshfeld atom refinement (HAR) approach, and the results are comparatively discussed.

The title compounds, C10H16O2Si (1) and C17H18OSi (2), are classified as dihydrofurylsilanes, which show great potential as building blocks for various functionalized silanes. They both crystallize in the space group P\overline{1} in the triclinic crystal system. Analyses of the Hirshfeld surfaces show packing-determining interactions for both compounds, resulting in a polymeric chain along the [011] for silane 1 and a layered-interconnected structure along the b-axis direction for silane 2.

Einleitung