Possible role of hydrogen cyanide in chemical evolution: The oligomerization and condensation of hydrogen cyanide

New Insights into the Characterization of ‘Insoluble Black HCN Polymers’

“…The GC/MS analyses of the insoluble black HCN polymers before hydrolysis and of the hydrolyzed insoluble residues were negative; no small polar molecules were detected. all samples contained large amounts of oxalic acid, urea, and glycine, as expected [13] [24]. These three compounds comprised ca.…”

“…It is important to note that C and O were the main contaminants in samples prepared in air and were also the main contaminants of the KBr pellets prepared. On the other hand, the C bonds were relatively well-defined by 13 C-CP-MAS-NMR and IR spectra. Therefore, only the high-resolution N 1s core level spectra were relevant for elucidation of the structures of the controversial Ncontaining functional groups in the insoluble black HCN polymers, which can be considered the distinctive fingerprint of the possible structures of the insoluble black HCN polymers.…”

“…We thank M. T. Fernández for recording the IR spectra, I. Sobrados from ICMM (Instituto de Ciencia de Materiales de Madrid, CSIC, Spain) for recording the 13 C-NMR spectra, and S. Veintemillas and G. Muñ oz-Caro for useful comments.…”

“…These IR bands were assigned to the following functional groups: 3084 cm À 1 (very broad), primary and secondary amines (OH groups of carboxylic acids, and ¼CH in aromatic and unsaturated hydrocarbons may overlap); 1725 and 1665 cm ), and ÀC¼O in carbonyl, carboxylic, and urea compounds (1735 and 1670 cm À 1 ). As in the FT-IR analysis, the 13 C-CP-MAS-NMR spectra of all of our samples were similar and resembled spectra obtained by Garbow et al [25] for the water-insoluble fraction as well as spectra reported by Mamajanov and Herzfeld [14] [15] for an HCN polymer prepared from gas HC 15 N and Et 3 N. The deconvoluted solid-state 13 C-NMR spectrum of our insoluble black HCN polymers displayed the following resonances: i) resonance at 168 ppm, which may correspond to amide groups (ÀCONH 2 ); ii) resonance at 159 ppm, which may correspond to imine and/or heterocyclic groups (ÀC¼NÀ); iii) a group of resonances at 154, 149, and 139 ppm, which may correspond to C-atoms of heterocyclic compounds containing N; iv) a group of low-intensity resonances between 130 and 100 ppm, which may correspond to alkenes ( = = C¼C = = ) and nitriles (ÀC N); and v) a third group of unresolved resonances between 100 and 60 ppm, which may correspond to C-atoms bound to a heteroatom, such as CÀ(N) of amines (Fig. 2, b).…”

“…Different Models Proposed in the Literature for HCN Polymers elucidate the structure of this polymer, we used the methodology we developed previously for the characterization of tholins [20] [21]. Data from the elemental analysis, FT-IR, 13 C-CP-MAS-NMR spectra, and GC/MS analysis of the insoluble black HCN polymers were compared to results previously reported in the literature. Additionally, we used X-ray photoelectron spectroscopy (XPS) to quantify various chemical species in powder samples [20 -22].…”