Spectral and Thermal Characterization of Halogen-Bonded Novel Crystalline Oligo(<i>p</i>‑bromoacetophenone formaldehyde)

A novel oligomer <i>p</i>-bromoacetophenone-formaldehyde (OPBAF) was prepared by condensation polymerization in the presence of an acid as catalyst. It was characterized by FT-IR, NMR, pyrolysis GC/MS, XRD, GPC, and TG-DTG. The crystallographic parameters and space group for hexagonal OPBAF were <i>a</i> = <i>b</i> = 2.0810 Å and <i>c</i> = 9.2340 Å and <i>P</i>3̅<i>m</i>1, respectively. The degradation activation energy of the oligomer was studied by the Kissinger method. The kinetic parameters were also obtained. Halogen bonding interactions in the crystalline oligomers are identified between halogen···carbonyl and halogen···halogen. Little correlation was found in the halogen bonding motifs exhibited as a function of bromine present in this oligomer, and a unique bifurcated Br···Br/Br···OC halogen bonding synthon was identified. This newly developed oligomer may be used as an interesting material for the development of 3D-designed structural products

SEM micrograph of cells fixed on A (a), B (b), C (c), and 316L (d).

<p>SEM micrograph of cells fixed on A (a), B (b), C (c), and 316L (d).</p

XRD pattern of the nickel-free powder metallurgy stainless steel samples.

<p>XRD pattern of the nickel-free powder metallurgy stainless steel samples.</p

Open circuit potential (<i>ocp</i>) vs. immersion time for the sample B.

<p>Open circuit potential (<i>ocp</i>) vs. immersion time for the sample B.</p

Chemical composition of the stainless steel samples (wt%).

<p>Chemical composition of the stainless steel samples (wt%).</p

Equivalent electrical circuit parameters obtained by the EIS studies.

<p>Equivalent electrical circuit parameters obtained by the EIS studies.</p

Potentiodynamic polarization curves for the stainless steel samples.

<p>Potentiodynamic polarization curves for the stainless steel samples.</p

Cell viability on the TCP and stainless steels after one day, determined by fluorescence in the cytoplasmic extract.

<p>Cell viability on the TCP and stainless steels after one day, determined by fluorescence in the cytoplasmic extract.</p

Bode impedance (a), Bode phase angle (b) and Nyquist (c) plots; and equivalent electrical circuit used for the quantitative analyses of the impedance spectra (d).

<p>Bode impedance (a), Bode phase angle (b) and Nyquist (c) plots; and equivalent electrical circuit used for the quantitative analyses of the impedance spectra (d).</p

Some properties of the stainless steel samples.

<p>Some properties of the stainless steel samples.</p