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Background: The expression of Coiled-Coil Domain Containing 134(CCDC134) is up-regulated in different pan-cancer species. However, its prognostic value and correlation with immune infiltration in breast cancer are unclear. Therefore, we evaluated the prognostic role of CCDC134 in breast cancer and its correlation with immune invasion. Methods: We downloaded the transcription profile of CCDC134 between breast cancer and normal tissues from the Cancer Genome Atlas (TCGA). CCDC134 protein expression was assessed by the Clinical Proteomic Cancer Analysis Consortium (CPTAC) and the Human Protein Atlas. Gene set enrichment analysis (GSEA) was also used for pathway analysis. Receiver operating characteristic (ROC) curve was used to differentiate breast cancer from adjacent normal tissues. Kaplan-Meier method was used to evaluate the effect of CCDC134 on survival rate. The protein-protein interaction (PPI) network is built from STRING. Function expansion analysis is performed using the ClusterProfiler package. Through tumor Immune Estimation Resource (TIMER) and tumor Immune System Interaction database (TISIDB) to determine the relationship between CCDC134 expression level and immune infiltration. CTD database is used to predict drugs that inhibit CCDC134 and PubChem database is used to determine the molecular structure of identified drugs. Results: The expression of CCDC134 in breast cancer tissues was significantly higher than that of CCDC134 mRNA expression in adjacent normal tissues. ROC curve analysis showed that the AUC value of CCDC134 was 0.663. Kaplan-meier survival analysis showed that patients with high CCDC134 had a lower prognosis (57.27 months vs 36.96 months, P = 2.0E-6). Correlation analysis showed that CCDC134 mRNA expression was associated with tumor purity immune invasion. In addition, CTD database analysis identified abrine, Benzo (A) Pyrene, bisphenol A, Soman, Sunitinib, Tetrachloroethylene, Valproic Acid as seven targeted therapy drugs that may be effective treatments for seven targeted therapeutics. It may be an effective treatment for inhibiting CCDC134. Conclusion: In breast cancer, upregulated CCDC134 is significantly associated with lower survival and immune infiltrates invasion. Our study suggests that CCDC134 can serve as a biomarker of poor prognosis and a potential immunotherapy target in breast cancer. Seven drugs with significant potential to inhibit CCDC134 were identified. [ABSTRACT FROM AUTHOR]

Triel bond, a recent emerging noncovalent interaction, has attracted extensive attention from physical and chemical scientists. Some triel atoms, such as Ga and In atoms, theirs valence, can be bivalent, trivalent, and even tetravalent. What is the influence of the valence of triel atom on the triel-bonding formation? This issue generates our initial research interest. Then, the influence of valence of triel atom on the triel bond has been theoretically investigated in thirty-two complexes composed by Lewis acids TrHX/TrH2X (Tr = Ga, In; X = F, Cl, Br, I) and Lewis base H2Y (Y = O, S) molecules at MP2/aug‐cc‐pVTZ(PP) theory level. MEP analyses show that both TrHX and TrH2X molecules possess π-holes on Tr atoms, which can be used as Lewis acids, and interact with Lewis bases to form triel bonds. AIM and Non-covalent interaction (NCI) analyses demonstrate that triel bond exists in all the studied thirty-two complexes. Hydrogen bond coexists with triel bond only in six of these complexes. In the process of triel bond formation, TrH2X molecule has stronger structural distortion than TrHX molecule. And TrH2X molecule can form a stronger triel bond than that of TrHX molecule by analyzing multiple factors that affect triel-bonding formation including substituents, electron donors, and nature of triel atoms. In addition, NBO analyses show that triel bond in TrH2X–H2Y complexes has stronger orbital interaction than that in TrHX–H2Y complexes. [ABSTRACT FROM AUTHOR]

Highlights: [•] The C7H7 ring can be either a heptahapto or pentahapto ligand in low-energy (C7H7)2V2(CO) n (n =5, 4, 3) structures. [•] (C7H7)2V2(CO) n (n =5, 4, 3) structures with V V triple bonds and 18-electron vanadium configurations are preferred. [•] A low-energy linear triplet (C7H7)2V2 structure has rare D 7h symmetry and a V V triple bond. [•] The lowest energy singlet (C7H7)2V2 structure has an ultrashort V–V distance of 1.84Å and a formal sextuple bond. [ABSTRACT FROM AUTHOR]

Both coaxial and perpendicular singlet spin state structures are found for the dibenzene dimetal complexes (CH)M (M = Fe, Mn, and Cr) using density functional theory. For (CH)M (M = Fe, Mn), the coaxial structure is the lower energy structure, whereas for (CH)Cr the perpendicular structure is the lower energy structure. These coaxial structures are predicted to have very short M-M distances of ~1.98 Å for (CH)Fe, ~1.75 Å for (CH)Mn, and ~1.68 Å for (CH)Cr. Investigation into the frontier molecular orbitals suggests a formal 2 π Fe=Fe double bond in (CH)Fe, a σ + 2 π Mn≡Mn triple bond in (CH)Mn, and a σ + 2 π + δ quadruple bond in (CH)Cr. This gives each metal atom in these coaxial (CH)M (M = Fe, Mn, Cr) derivatives a 16-electron configuration suggesting an 8-orbital d p metal valence orbital manifold without the involvement of the s orbital. The coaxial (CH)M (M = Fe, Mn) derivatives have ideal sixfold D symmetry. However, distortion of coaxial (CH)Cr from D symmetry to D symmetry is observed because of involvement of only one orbital from the { d( xy), d( x − y)} set of δ symmetry of each chromium atom in the [InlineMediaObject not available: see fulltext.] formal quadruple bond. [ABSTRACT FROM AUTHOR]

The double-proton transfer reactions in Watson–Crickguanine–cytosine(GC) base pairs after hydrogen atom addition are studied theoretically.The structural changes and energy differences among the structuresare compared to explore the double-proton transfer mechanisms, concertedand stepwise. The concerted mechanism is found in all five radicals(GC)•considered, while the stepwise mechanismis predicted only for structures G–H•CC6and H•GN7–C. The geometricalfeatures have been found to change regularly in the concerted double-protontransfer. This is different from the single-proton transfer, for whichthe structural perturbations are dispersed throughout the GC basepair. The energy analyses demonstrate that the concerted double-protontransfer mechanism is more favorable in the gas phase, while the stepwisemechanism dominates in water. The structures of proton transfer productsbecome less favored energetically. [ABSTRACT FROM AUTHOR]

Soluble guanylate cyclase (sGC) mediates NO signaling for a wide range of physiological effects in the cardiovascular system and the central nervous system. The α1β1 isoform is ubiquitously distributed in cytosolic fractions of tissues, whereas α2β1 is mainly found in the brain. The major occurrence and the unique characteristic of human sGC α2β1 indicate a special role in the mediation of neuronal communication. We have efficiently purified and characterized the recombinant heme-binding domain of the human sGC α2 subunit (hsGC α2) and heterodimeric α2β1 (hsGC β1-α2) by UV-vis spectroscopy, circular dichrosim spectroscopy, EPR spectroscopy, and homology modeling. The heme dissociation and related NO/CO binding/dissociation of both hsGC α2 and hsGC β1-α2 were investigated. The two truncated proteins interact with heme noncovalently. The CO binding affinity of hsGC α2 is threefold greater than that of human sGC α1, whereas the dissociation constant k for dissociation of NO from hsGC α2 is sevenfold larger than that for dissociation of NO from hsGC α1, although k is almost identical. The results indicate that in comparison with the α1β1 isoform, the brain α2β1 isoform exhibits a distinctly different CO/NO affinity and binding rate in favor of NO signaling, and this is consistent with its physiological role in the activation and desensitization. Molecular modeling and sequence alignments are consistent with the hypothesis that His105 contributes to the different CO/NO binding properties of different isoforms. This valuable information is helpful to understand the molecular mechanism by which human sGC α2β1 mediates NO/CO signaling. [ABSTRACT FROM AUTHOR]

The effects of temperature and solution concentration on the structure of triblock polymeric surfactant (ethylene oxide)19(propylene oxide)29(ethylene oxide)19 (Pluronic P65) have been investigated by fully atomistic molecular dynamics simulations. The Flory–Huggins interaction parameter χ, hydrogen bonding and molecular mobility in the aqueous solution of P65 were investigated covering a composition range of 0.1–0.73 (water weight fraction) and a temperature range of 273–373 K. The Flory–Huggins parameters indicated that propylene oxide (PO) segments became hydrophobic with the increase in temperature, whereas ethylene oxide (EO) segments remained hydrophilic, which caused the increase in repulsion between EO and PO segments. The intermolecular hydrogen bonds in P65 solution including water–water hydrogen bonds and water–P65 hydrogen bonds increased with the increase in solution concentration and decreased with the increase in temperature. The critical micellar temperature of Pluronic P65 predicted by Flory–Huggins interaction parameter χ and hydrogen bonding was in good agreement with experimental data. [ABSTRACT FROM PUBLISHER]

Abstract: Density functional theory methods (B3LYP and BP86) indicate that the preferred structures for such early transition metal derivatives are (η8-C8H8)M(η4-C8H8) (M=Ti, V, Cr) with one octahapto η8-C8H8 ring and one tetrahapto η4-C8H8 ring. In such structures only 12 of the 16 carbon atoms of the two C8H8 rings are bonded to the metal, leading to 16-, 17-, and 18-electron complexes, respectively, in accord with the experimentally known structures for the Ti and V derivatives. The preferred structures for the Mn and Fe derivatives are (η6-C8H8)M(η4-C8H8) (M=Mn, Fe) with one hexahapto and one tetrahapto C8H8 ring and thus having 17- and 18-electron configurations, respectively, in accord with experimental data on the iron complex. The lowest energy structure for the cobalt complex is (η4-C8H8)Co(η2,2-C8H8) with two different types of tetrahapto C8H8 rings and a 17-electron metal configuration. The nickel complex (C8H8)2Ni appears to prefer a structure with a 16-electron configuration and two trihapto C8H8 rings, similar to the known (η3-C3H5)2Ni rather than a bis(tetrahapto) structure with the favored 18-electron configuration. These theoretical studies indicate that in (C8H8)2M derivatives of the first row transition metals, the number of carbon atoms in the pair of C8H8 rings involved in the bonding to the central metal atom gives the metal atoms 16-, 17-, or 18-electron configurations. [Copyright &y& Elsevier]

Abstract: The two cyclooctatetraene metal carbonyls that have been synthesized are the tetrahapto derivative (η4-C8H8)Fe(CO)3 and the hexahapto derivative (η6-C8H8)Cr(CO)3 using the reactions of cyclooctatetraene with Fe(CO)5 and with fac-(CH3CN)3Cr(CO)3, respectively. Related C8H8M(CO) n (M=Ti, V, Cr, Mn, Fe, Co, Ni; n =4, 3, 2, 1) species have now been investigated by density functional theory in order to explore the scope of cyclooctatetraene metal carbonyl chemistry. In this connection, the existence of octahapto (η8-C8H8)M(CO) n species is predicted as long as the central metal M does not exceed the 18-electron configuration by receiving eight electrons from the η8-C8H8 ring. Thus the lowest energy structures (η8-C8H8)Ti(CO) n (n =3, 2, 1), (η8-C8H8)M(CO) n (M=V, Cr; n =2, 1), and (η8-C8H8)Mn(CO) all have octahapto η8-C8H8 rings. An exception is (η6-C8H8)Fe(CO), with a hexahapto η6-C8H8 ring and thus only a 16-electron configuration for the iron atom. Hexahapto (η6-C8H8)M(CO) n structures are predicted for the known (η6-C8H8)Cr(CO)3 as well as the unknown (η6-C8H8)Ti(CO)4, (η6-C8H8)V(CO)3, (η6-C8H8)Mn(CO)2, and (η6-C8H8)Fe(CO)2 with 18, 18, 17, 17, and 18 electron configurations, respectively, for the central metal atoms. There are two types of tetrahapto C8H8M(CO) n complexes. In the 1,2,3,4-tetrahapto (η4-C8H8)M(CO) n complexes two adjacent Cbonds, forming a 1,3-diene unit similar to butadiene, are bonded to the metal atom. In the 1,2,5,6-tetrahapto (η2,2-C8H8)M(CO)3 derivatives two non-adjacent Cbonds of the C8H8 ring are bonded to the metal atom. The known (η4-C8H8)Fe(CO)3 is a 1,2,3,4-tetrahapto complex. The unknown isomeric 1,2,5,6-tetrahapto complex (η2,2-C8H8)Fe(CO)3 is predicted to lie ∼15kcal/mol above (η4-C8H8)Fe(CO)3. The related 1,2,5,6-tetrahapto complexes (η2,2-C8H8)Cr(CO)4, (η2,2-C8H8)Mn(CO)4, [(η2,2-C8H8)Mn(CO)3]−, (η2,2-C8H8)Co(CO)2, and (η2,2-C8H8)Ni(CO)2 are all predicted to be low-energy structures. [Copyright &y& Elsevier]

The influence of monomer deformation on the formation of triel and tetrel bonds has been theoretically investigated, incorporating 18 binary complexes of TrR 3 /TR 4 ···N‐base (Tr = Al, Ga, In; T = Si, Ge, Sn and N‐base = HCN, NH 3 , CN−). The monomer deformation is an important factor to facilitate the formation of triel and tetrel bonds. The results reveal how important these geometric deformations are, and how they affect the formation of triel and tetrel bonds. [Display omitted] • The deformation energies display a remarkable sensitivity to the Tr/T atoms in triel/tetrel-bonded complexes. • The deformation of Lewis acid molecule has more important contribution to the formation of triel/tetrel-bonds. • The monomer deformation helps increase the electrostatic attraction between two monomers. A series of Lewis acid TrF 3 and TF 4 molecules (Tr = Al, Ga, In and T = Si, Ge, Sn) were allowed to engage in triel and tetrel bonds, respectively, with HCN, NH 3 , and CN− Lewis base. The interaction energies are quite large, approaching 96 kcal/mol in some cases. The deformation energy of Lewis acid monomer is larger than that of Lewis base monomer. The binding energy, which takes deformation energy into account, is thus significantly lower than the interaction energy, particularly for the complexes containing Al or Sn central atom. The triel and tetrel bonds can still form even if the Lewis acid and Lewis base molecule are not allowed to adjust their internal geometries, but their interaction energies are drastically weakened, dropping by 18% to 90%. The monomer deformation also contributes to the complexation by strengthening its π/σ-hole by up to 2.6 times. [ABSTRACT FROM AUTHOR]

The performance of ab initio methods (MP2, DFT/B3LYP, random-phase approximation (RPA), CCSD(T) and QCISD(T)) in predicting interaction energy of X H⋯π (X H = HCCH, HCl, HF; π = C 2 H 2 , C 2 H 4 , C 6 H 6 ) hydrogen complexes are assessed systematically. The CCSD(T)/CBS benchmarks of interaction energy are reported. It is found that RPA agrees well with CCSD(T)/CBS benchmarks and experimental results. CCSD(T) and QCISD(T) perform the best only when compared with CCSD(T)/CBS benchmarks, MP2 performs well only for experimental data. B3LYP provides the worst accuracy. Additionally, the equilibrium structure, interaction type of X H⋯π hydrogen complexes are investigated by the natural bond orbital (NBO) and the non-covalent interaction index (NCI). [ABSTRACT FROM AUTHOR]

Abstract: Two 2-pyrazoline derivatives of 1-phenyl-3-(4-methylphenyl)-5-phenyl-2-pyrazoline (1) and 1-phenyl-3-(4-methylphenyl)-5-(2,4-dichlorophenyl)-2-pyrazoline (2) have been synthesized and characterized by elemental analysis, IR, UV–vis and fluorescence spectroscopy. The crystal structure of 2 has been determined by X-ray single crystal diffraction. For the two compounds, density functional theory (DFT) calculations of the structures and natural population atomic charge analysis have been performed at B3LYP/6-311G** level of theory. By using TD-DFT method, electron spectra of 1 and 2 have been predicted, which suggests the B3LYP/6-311G** method can approximately simulate the electron spectra for the system presented here. Comparative studies on 1 and 2 indicate that the change of substituent in 5-phenyl ring of pyrazoline ring influences the peak location and intensity in electronic and fluorescence spectra. [Copyright &y& Elsevier]

• The products distributions and heat sinks of 31 hydrocarbons pyrolysis under 600-700 °C and 3.0 MPa were provided. • The relationship between hydrocarbon molecular structure and pyrolysis behaviors were discussed in detail. • The normal alkanes, mono-substituted alkanes and n -alkylcyclohexanes are more suitable for the high heat-sink EHFs. Understanding the relationship of hydrocarbon chemical structure and pyrolysis is of great significance for both composition designing/screening and optimization of endothermic hydrocarbon fuels (EHFs). In this work, the pyrolysis of C 8 to C 16 hydrocarbons (9 normal alkanes, 14 iso- alkanes and 8 cycloalkanes) were studied on a high-pressure micro pyrolysis reactor equipped with GC-MS/FID at 600−700 °C and 3.0 MPa. The pyrolysis of iso- alkanes produces more C 3 or C 4 alkenes and less C 2 H 4 than normal alkanes due to the presence of substituent and less CH 2 groups. Based on the conversion and products distributions, the heat sink index (HSI) of hydrocarbons was defined to characterize their physical and endothermic heat sink. For alkanes with same carbon number, the HSI of iso- alkanes with monosubstituent in the central carbon chain is the highest, following by normal alkanes, dimethylalkanes, indicating the significant impacts of the position and number of substituents. While for cycloalkanes, n- alkylcyclohexanes had relatively higher HSIs. Generally, the new insights into hydrocarbon molecular structure-products distributions/heat sink relationships are important for the EHFs design and production for advanced aircrafts. [ABSTRACT FROM AUTHOR]

Abstract We theoretically study chalcogen bonds involving SF 2 and SFH, each paired with various unsaturated hydrocarbons ethyne, ethene, 1,3-butadiene, and benzene. The binding energies are calculated at theory level MP2, M06-2X-D3 and CCSD(T)/CBS, respectively. Geometry structure, binding energies, interaction type and strength are studied comparatively. SFH engages in a stronger chalcogen bond than does SF 2 for all systems, which indicates that SFH is a stronger electron acceptor than SF 2. Two kinds of energetic effects are observed, SF 2 ···cis-butadiene complex contain the strongest chalcogen bond among all the SF 2 ···π complexes, which is attributed to the energetic effect of two S···π interactions. For SFH···π complexes, the strongest interaction is formed between SFH and C 6 H 6 , which can be explained by the synergistic effects of the S···π and S H···π interaction. The largest charge transfer arises from the occupied C C bonding orbital to the σ*(S F) antibonding orbital. The quantity is considerably larger for SFH than for SF 2. Highlights • The binding energies are calculated at different theory level including MP2, M06-2X-D3, and high-level CCSD(T)/CBS. • The formation of chalcogen bond is investigated comparatively by MEP, NBO, ELF and NCI methods. • Two kinds of energetic effects with additive aspects are observed. • The results show that SFH is a stronger electron acceptor than SF 2 in forming chalcogen bond. [ABSTRACT FROM AUTHOR]

Molecular structure is vitally important for the selective optimization of energy level and improving the interfacial charge transfer performance of dye-sensitized solar cells (DSSCs). With appropriate auxiliary acceptor, the organic sensitizer owing D-A-π-A structure can act as a promising efficient sensitizer for DSSCs. Herein, considering the conjugated π-system and electron-withdrawing capability, dyes CS-71 and CS-72 were designed and synthesized with naphthothiadiazole and naphthobisthiadiazole units as the auxiliary acceptors, respectively, while the benzothiadiazole unit was applied as the auxiliary acceptor for the reference dye CS-70. The structure-activity relationship between the molecular structure characteristics, including steric hindrance, π-conjugation system, and electron-withdrawing capability of the auxiliary acceptors, and the properties of the dye are systematically investigated. Ascribed to the extended auxiliary acceptor moieties, CS-71 and CS-72 obtained obvious downward shift LUMO levels accompanying with the HOMO levels remaining unchanged, with respect to the reference dye CS-70. Owing to the shrinked energy gap, their absorption spectra were also significantly bathochromic shifted, resulting in the effectively broadened light-harvesting region. Combining the improved charge injection process, cell devices sensitized by CS-72 achieves an optimal PCE of 7.17%, presenting us a promising way to obtain highly efficient organic sensitizer in the future. • Novel auxiliary acceptors are applied to develop efficient D-A-π-A dyes. • The energy level and charge injection process of the dyes are selectively optimized. • The auxiliary acceptor plays a critical role in improving the performance of the dye. [ABSTRACT FROM AUTHOR]

• Based on CSD search, chalcogen bonds can be composed of C 4 N 4 Ch (Ch=S, Se, Te) and anions. • The strongest chalcogen bond was formed between SO 4 2 − and C 4 N 4 Te monomers. • These studied chalcogen bonds are dominated by electrostatic interaction. • Double chalcogen bond was confirmed to exist in these studied complexes. In recent years, due to the high directionality and adjustable strength, chalcogen bonds have attracted extensive attention from both crystal engineering and theoretical perspectives. A search of the Cambridge Structural Database (CSD) has revealed a large number of crystal structures containing chalcogen group elements and anions. On this basis, some typical structures containing chalcogen group elements C 4 N 4 Ch (Ch=S, Se and Te) and anions X (X= F − , C l − , B r − , NO 3 − and SO 4 2 −) were chosen to form the Ch ⋯ X chalcogen bond. The properties of these chalcogen bonds are analyzed in detail, including bond lengths, interaction energies, charge transfer, electron densities and energy decomposition analyses. The results show that these studied Ch ⋯ X chalcogen bonds dominated by electrostatic interactions have large interaction energy, reaching a maximum of 97.41 kcal/mol in the case of C 4 N 4 Te ⋯ SO 4 2 − complex. Interestingly, the double chalcogen bond is found in these studied C 4 N 4 Ch ⋯ X complexes. The chalcogen bond Ch...X is formed by Lewis acid C 4 N 4 Ch (Ch=S, Se and Te) molecular and Lewis base anion X (X= F − , C l − , B r − , NO 3 − and SO 4 2 −), especially the structure of C 4 N 4 Te and C 4 N 4 Te...F exist in crystal database. The versatility and formation of chalcogen bond in C 4 N 4 Ch...X complexes are analyzed at MP2/aug-cc-pVTZ(PP) theory level. The research shows that the Lewis base anion X can form relatively strong chalcogen bonds, and the nature of these studied chalcogen bond is electrostatic interaction. Interestingly, double chalcogen bond are found in C 4 N 4 Ch...X complexes. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights: [•] A cis-(η5,η5-C8H6)Co2(CO)4 structure related to the experimental structure is predicted. [•] The Co–Co interaction in cis-(η5,η5-C8H6)Co2(CO)4 has a Wiberg bond index of only 0.06. [•] The low-energy (C8H6)Co2(CO) n (n =3, 2) structures also have pentahapto pentalene ligands. [•] The carbonyl-rich (C8H6)Co2(CO) n (n =6, 5) structures illustrate considerable diversity of pentalene bonding modes. [Copyright &y& Elsevier]

The structural and electronic properties of σ-hole triel-bonded interactions in binary C 5 H 5 Tr⋯N‐base and ternary Li+⋯C 5 H 5 Tr⋯N‐base (Tr B, Al, Ga and N‐base NCH, NH 3 , NC−) complexes were studied systematically. The cooperativity effect and solvation effect were further investigated. The results reveal that strong σ-hole triel-bonds exist in binary C 5 H 5 Tr⋯N‐base complexes, and there is positive cooperativity effect between triel-bonded/cation– π interactions in ternary Li+⋯C 5 H 5 Tr⋯N‐base complexes. The cooperative effects will decrease in water phase, due to the large weakening of the cation– π interactions. [Display omitted] • Strong σ -hole triel-bonds exist in binary C 5 H 5 Tr⋯N-base complexes. • There is positive cooperativity effect between triel-bonded/cation– π interactions in ternary Li+⋯C 5 H 5 Tr⋯N‐base complexes. • The cooperative effects will decrease in water phase, due to the large weakening of the cation– π interactions. The σ-hole triel-bonded and cation– π interactions are constructed in binary C 5 H 5 Tr⋯N‐base and ternary Li+⋯C 5 H 5 Tr⋯N‐base complexes (Tr B, Al, Ga and N‐base NCH, NH 3 , NC−). A positive region of electrostatic potential appears near the triel (Tr B, Al, Ga) atom in the plane of the aromatic ring after replacing the CH group of benzene by a triel atom. Using MP2/aug-cc-pVTZ method, the solvation effect and cooperativity effect were investigated by MEP, ELF, AIM and SAPT analysis. The results indicate that the cooperative effects between σ-hole triel-bonded and cation– π interactions in Li+⋯C 5 H 5 Tr⋯N‐base complexes are positive and will be weakened in water environment. [ABSTRACT FROM AUTHOR]

Abstract: This study has defined the average molecular structure of kerogen from Huadian oil shale containing both atomic and molecular information. Pyrolysis–gas chromatography–mass spectroscopy (Py–GC–MS) has been used to chemically characterize the main structural skeleton in this kerogen. The geometry optimized configuration was obtained by molecular mechanics and molecular dynamics simulation methods. The constructed average structure was evaluated by simulation of 13C MAS NMR spectrum. The simulated value for the physical density was fitted in with experiment data. Based on the studies of reaction sites using semi-empirical method, we speculated that the kerogen pyrolysis can be divided into three stages. Such an average structure can serve as a starting point for theoretical studies on representations of the Huadian kerogen at molecular scale. [Copyright &y& Elsevier]