Structure, Dynamics, and Accurate Laboratory Rotational Frequencies of the Acrylonitrile–Methanol Complex

The hydrogen-bonded complex between acrylonitrile (CH2=CHCN) and methanol has been characterized spectroscopically in the millimeter wave range (59.6-74.4 GHz) using a free jet absorption millimeter wave spectrometer. Precise values of the rotational and centrifugal distortion constants were obtained from the measured frequencies of the complex of acrylonitrile with CH3OH and CD3OD. The analysis of the splittings of the rotational lines due to the hindered internal rotation of the methanol methyl group led to the determination of a V-3 value of 221.9(7) and 218(5) cm(-1) for the complexes of CH3OH and CD3OD, respectively, and these values are about 40% lower than that of free methanol. The structure of the observed conformation is in agreement with the global minimum determined at the MP2/aug-cc-pVTZ level of calculation, and the counterpoise corrected intermolecular binding energy, obtained at the same theoretical level, is D-e = 26.3 kJ mol(-1)We thank the University of Bologna for funding (RFO). C.C. acknowledges the Spanish Government (MINECO, Project Code CTQ2017-89150-R) for a postdoctoral contract. W.D.G. acknowledges support from the Swedish Research Council (Vetenskapsradet), Grant Number 2019-04332. We thank R. A. Boto and J. Contreras-Garcia for the availability of the NCI 2D plot script

Ion-neutral reactions of C2H2N+ with hydrocarbons : relevant to Titan’s ionosphere

To provide some insights on the formation of long-chain carbon-nitrogen bearing ions in Titan’s atmosphere, laboratory measurements of ion-neutral reactions were conducted and results are presented in the following licentiate thesis. The product ions of the C2H2N+ reaction with saturated and unsaturated neutral hydrocarbons have been studied using guided ion beam mass spectrometer (GIB-MS). The data have been used to infer the product ion signal intensity dependences on pressure and collision energies to obtain information on the reactions contributing to these signals. Theoretical calculations have been carried out to interpret these measurements and to elucidate the reaction pathways leading to the observed product ions. This study provides understanding on the formation of long-chain carbon-nitrogen bearing ions through exothermic and barrierless ion-neutral reactions which are of interest as possible formation routes to heavy positive ions detected in Titan’s atmosphere by Cassini’s ion neutral mass spectrometer (INMS)

Synthesis of complex organics via molecular growth mechanisms : Combined experimental and theoretical studies on ion-neutral reactions of C2H2N+ with ubiquitous hydrocarbons in Titan's ionosphere

To provide insights on the molecular growth mechanisms leading to large carbon and nitrogen-bearing species in Titan’s ionosphere, laboratory measurements of ion-neutral reactions were conducted and the results are presented in the following doctoral dissertation. The product ions of the C2H2N+ reactions with saturated and unsaturated neutral hydrocarbons have been investigated using Guided Ion Beam Mass Spectrometer (GIB-MS). The data have been used to reveal the dependence of product ion intensity on pressure and also with respect to collision energy variations to derive useful insights on the nature of chemical reactions leading to the observed species. Complementary theoretical calculations have been also carried out to assist in interpretation of these measurements and to elucidate the reaction schemes. This study provides comprehensive insights on the formation of long chain and heavy carbon-nitrogen bearing species through exothermic and barrierless ion-neutral reactions which are likely to play a significant role in the formation routes of heavy positive ions of interest, which have been detected in Titan’s ionosphere by Cassini’s Ion Neutral Mass Spectrometer (INMS).At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Submitted.</p

Millimeter Wave Spectrum of the Weakly Bound Complex CH2=CHCN·H2O: Structure, Dynamics, and Implications for Astronomical Search

The weakly bound 1:1 complex between acrylonitrile (CH2=CHCN) and water has been characterized spectroscopically in the millimeter wave range (59.6-74.4 GHz) using a Free Jet Absorption Millimeter Wave spectrometer. Precise values of the rotational and quartic centrifugal distortion constants have been obtained from the measured frequencies of the normal and isotopically substituted water moiety (DOH, DOD, H18OH). Structural parameters have been estimated from the rotational constants and their differences among isotopologues: the complex has a planar structure with the two subunits held together by a O-H···N (2.331(3) Å) and a C-H···O (2.508(4) Å) interaction. The ab initio intermolecular binding energy, obtained at the counterpoise corrected MP2/aug-cc-pVTZ level of calculation, is De = 24.4 kJ mol-

Millimeter Wave Spectrum of the Weakly Bound Complex CH₂CHCN·H₂O: Structure, Dynamics, and Implications for Astronomical Search

The weakly bound 1:1 complex between acrylonitrile (CH₂CHCN) and water has been characterized spectroscopically in the millimeter wave range (59.6–74.4 GHz) using a Free Jet Absorption Millimeter Wave spectrometer. Precise values of the rotational and quartic centrifugal distortion constants have been obtained from the measured frequencies of the normal and isotopically substituted water moiety (DOH, DOD, H¹⁸OH). Structural parameters have been estimated from the rotational constants and their differences among isotopologues: the complex has a planar structure with the two subunits held together by a O–H···N (2.331(3) Å) and a C–H···O (2.508(4) Å) interaction. The <i>ab initio</i> intermolecular binding energy, obtained at the counterpoise corrected MP2/aug-cc-pVTZ level of calculation, is <i>D</i>_e = 24.4 kJ mol^–1

Global, regional, and national incidence of six major immune-mediated inflammatory diseases: findings from the global burden of disease study 2019Research in context

Summary: Background: The causes for immune-mediated inflammatory diseases (IMIDs) are diverse and the incidence trends of IMIDs from specific causes are rarely studied. The study aims to investigate the pattern and trend of IMIDs from 1990 to 2019. Methods: We collected detailed information on six major causes of IMIDs, including asthma, inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, psoriasis, and atopic dermatitis, between 1990 and 2019, derived from the Global Burden of Disease study in 2019. The average annual percent change (AAPC) in number of incidents and age standardized incidence rate (ASR) on IMIDs, by sex, age, region, and causes, were calculated to quantify the temporal trends. Findings: In 2019, rheumatoid arthritis, atopic dermatitis, asthma, multiple sclerosis, psoriasis, inflammatory bowel disease accounted 1.59%, 36.17%, 54.71%, 0.09%, 6.84%, 0.60% of overall new IMIDs cases, respectively. The ASR of IMIDs showed substantial regional and global variation with the highest in High SDI region, High-income North America, and United States of America. Throughout human lifespan, the age distribution of incident cases from six IMIDs was quite different. Globally, incident cases of IMIDs increased with an AAPC of 0.68 and the ASR decreased with an AAPC of −0.34 from 1990 to 2019. The incident cases increased across six IMIDs, the ASR of rheumatoid arthritis increased (0.21, 95% CI 0.18, 0.25), while the ASR of asthma (AAPC = −0.41), inflammatory bowel disease (AAPC = −0.72), multiple sclerosis (AAPC = −0.26), psoriasis (AAPC = −0.77), and atopic dermatitis (AAPC = −0.15) decreased. The ASR of overall and six individual IMID increased with SDI at regional and global level. Countries with higher ASR in 1990 experienced a more rapid decrease in ASR. Interpretation: The incidence patterns of IMIDs varied considerably across the world. Innovative prevention and integrative management strategy are urgently needed to mitigate the increasing ASR of rheumatoid arthritis and upsurging new cases of other five IMIDs, respectively. Funding: The Global Burden of Disease Study is funded by the Bill and Melinda Gates Foundation. The project funded by Scientific Research Fund of Sichuan Academy of Medical Sciences &amp; Sichuan Provincial People's Hospital (2022QN38)