Cationic P⋯N interaction in XH3P+⋯NCY complexes (X = H,F, CN,NH2, OH; Y = H,Li, F,Cl) and its cooperativity with hydrogen/lithium/halogen bond

The geometries, interaction energies and bonding properties of cationic pnicogen bond (CPB) interactions are studied in binary XH₃P⁺⋯NCY (X = H, F, CN, NH₂, OH; Y = H, Li, F, Cl) complexes by means of MP2/aug-cc-pVTZ calculations. Interaction energies of these binary complexes span a large range, from −16.36 kcal/mol in (NH₂)H₃P⁺⋯NCF to −71.36 kcal/mol in FH₃P⁺⋯NCLi complex. The spin–spin coupling constant across P⋯N interaction depends considerably on the nature of X and Y substituents. The characteristic of CPB interactions is analyzed in terms of parameters derived from quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analyses. The charge transfer from the nitrogen base to the cationic acid stabilizes these pnicogen–bonded complexes. For a given XH₃P⁺, the net charge transfer value increases as the interaction energy of the complex becomes more negative, i.e., NCLi > NCCl > NCH > NCF. Moreover, mutual influence between the CPB and hydrogen/halogen/lithium bond is studied in the ternary XH₃P⁺⋯NCY⋯NCH complexes. The results indicate that the formation of a Y⋯N interaction tends to strengthen CPB in the ternary systems.     

Phase relationship in V2O3-rich region of the V2O3–CaO system between 1573–1773 K at PO2 = 10−10 and 10−11 atm

V₂O₃–CaO system is one of the fundamental systems in the fields of vanadium extraction and vanadium-containing alloys production. Due to the insufficient experimental study, the data of this system was limited. The present study was carried out between 1300 and 1500 °C (1573–1773 K) at the V2O3-rich region (>56 wt% V₂O₃), with the controlled partial pressure of oxygen (PO2) at 10-10 and 10–11 atm. High-temperature equilibration experiments, quenching technique and electron probe micro-analyser (EPMA) were adopted to determine the microstructures and compositions of phases at high temperature. The results of phase compositions obtained were used to plot a sub-solidus phase diagram, which showed a great discrepancy with existing publications, and 4 solid-phase regions with their phase boundaries were identified in the present study. The solubility of CaO in V2O3 was found to increase slightly with the temperature under both PO2. The study is expected to fulfil the gaps of thermodynamics information in the V₂O₃-containing systems.     

分子C_nX_4(n=28,40;X=H,F,Cl)的振动光谱的密度泛函理论研究(英文)

本文中,首先证明了nX4(n=28,40;X=H,F,Cl)分子最稳定的结构具有Td对称性.利用密度泛函理论研究了nX4的振动光谱.从频率分析中我们得到当修饰性的原子位于Td寸称性的C28X4和C40X4的势能面上的4个顶点时,分子的能量具有最低值.我们还将CnX4(n=28,40;X=H,F,Cl)和CX4的振动光谱进行对比,得出笼的骨架振动.频率分析中具有最大波数的频率对应分子的笼骨架振动,所以对于C28X4(X=H,F,Cl)或C40X4(=H,F,Cl)来说,修饰原子的改变对这个频率值基本上没有影响.但是碳笼骨架上碳原子数的改变对这个频率的影响非常大.     

计算基态X(X=Li-Ne,HC,H2 C)电子相关能的研究

为深入系统研究电子相关能计算理论,本文报道在6-311 G*基组水平用CISD(configuration interaction with singly and doubly excited configurations)方法计算基础体系X(X=Li-Ne,Hc,H2c)对内、对间电子相关能.结果表明不同元素所形成的基态X(X=Li-Ne,HC,H2C)体系,其价层电子对内、对间相关能的变化较大,它们之间存在着轨道差别,不宜将其相关贡献归为简单的常数.以使用相同理论方法和相同质量基组为前提,电子数直接影响电子对间相关能的大小.对于多电子体系,电子对间相关在总相关中占优势,若忽略则会产生较大误差.     

H_2M(CO)_4(M=Fe,Ru,Os)···CH_3OH/H_2O中弱相互作用的理论研究

金属氢化物因其在有机化学、药物化学及工业生产中发挥着重要作用而备受关注。本文利用量子化学计算方法,使用w B97xd密度泛函,Ru和Os原子采用aug-cc-pVDZ-PP、其它原子采用aug-cc-pVDZ基组,对由金属氢化物H_2M(CO)_4(M=Fe,Ru,Os)和常见小分子CH_3OH/H_2O间形成的复合物H_2M(CO)_4…CH_3OH/H_2O(M=Fe,Ru,Os)中的弱相互作用进行了研究。采用电子密度拓扑分析方法分析了复合物中MH…H键键的作用本质。计算结果表明,此类MH…H相互作用属于闭壳层弱相互作用;对于相同的电子给体,H_2M(CO)_4(M=Fe,Ru,Os)与CH_3OH形成的MH…H作用要强于其与H_2O形成的MH…H作用;对相同的电子受体,MH…H相互作用的强度按照M=Fe,Ru,Os的顺序依次增强。     

用密度泛函论分析X-CH2-CH2-X(X=H,CH3,OH,NH2,SH,F,Cl,Br,I)的构象

为了研究X-CH2-CH2-X(X=H,CH3,OH,NH2,SH,F,Cl,Br)的构象,采用密度泛函理论的量子化学计算方法,扫描其势能面,分析其典型构象,一一得出稳定构象,并分析了最影响其稳定构象的原因.结果表明,对于正丁烷、1,2-二氯乙烷、1,2-二溴乙烷和乙二巯醇,对位交叉构象最稳定,影响其最稳定构象的主要因素是空间作用;对于乙二醇,乙二胺,邻位交叉式为其最稳定的构象,该构象稳定的主要因素是分子内氢键;偶极-偶极相互作用导致1,2-二氟乙烷的最稳定构象是邻位交叉式;超共轭作用导致乙烷的最稳定构象为对位交叉.用理论化学计算,可以确定分子的最稳定构象,应从多方面分析影响分子最稳定构象的原因.     

Linear σ-hole⋯CO⋯σ-hole intermolecular interactions between carbon monoxide and dihalogen molecules XY (X,Y = Cl,Br)

Carbon monoxide can interact with two dihalogen molecules XY (X, Y = Cl, Br) in the form of X(Y)⋯COX(Y)⋯CO⋯X(Y)X(Y) trimeric complex, and their nature and characteristics were investigated at MP2/aug-cc-pVDZ level without and with counterpoise method, together with single point calculations at CCSD(T)/aug-cc-pVDZ level. The optimized geometries, stretching modes and interaction energies of a series of X(Y)⋯COX(Y)⋯CO⋯X(Y)X(Y) trimeric complexes were obtained and discussed. The cooperativity in these complexes was evaluated. EDA analyses reveal that the electrostatic interaction is the dominant net driving force in each trimer, but the contributions of other interactions like exchange, dispersion and polarization interactions are also important. QTAIM and NCI analyses confirm the existence of attractive halogen-bonding interactions. Additionally, EDDMF analysis was employed for the component dimers of these trimers, which indicates that the formation of halogen-bonding interactions is closely related to the charge shift and the rearrangement of electronic density in the formation of these complexes. The results would provide valuable insight into for these linear halogen bonds.     

Evolution of structure,stability, and nonlinear optical properties of the heterodinuclear CNLin (n = 1–10) clusters

The lowest-energy structures and stabilities of the heterodinuclear clusters, CNLi_n (n = 1–10) and relevant CNLi_n⁺ (n = 1–10) cations, are studied using the density functional theory with the 6-311 + G(3df) basis set. The CNLi₆ and CNLi₅⁺ clusters are the first three-dimensional ones in the CNLi_n^0/+ series, respectively, and the CN group always caps the Li_n^0/+ moiety in the CNLi_n^0/+ (n = 1–9) configurations. The CN triple bond is found to be completely cleaved in the CNLi₁₀^0/+ clusters where the C and N atoms are bridged by two Li atoms. The CNLi_n (n = 2–10) clusters are hyperlithiated molecules with delocalized valence electrons and consequently possess low VIP values of 3.780–5.674 eV. Especially, the CNLi₈ and CNLi₁₀ molecules exhibit lower VIPs than that of Cs atom and can be regarded as heterobinuclear superalkali species. Furthermore, these two superalkali clusters show extraordinarily large first hyperpolarizabilities of 19,423 and 42,658 au, respectively. For the CNLi_n⁺ cationic species, the evolution of the energetic and electronic properties with the cluster size shows a special stability for CNLi₂⁺.     

Phase relationship in the system MgO-V2O3 between 1661 and 1873 K at PO2=(3.55±0.2)×10-6 and (3.55±0.3)×10-5 Pa

The composition ranges of the phases in the pseudo binary system MgO-V₂O₃ were studied between 1661 and 1873 K and at controlled oxygen partial pressures of (3.55 ± 0.2) × 10^-6 and (3.55 ± 0.3) × 10^-5 Pa. The phase relationship was determined by equilibrating MgO-V₂O₃ pellets in a CO-CO₂ mixture followed by quenching and electron-probe microanalysis. To ensure sufficient quenching, a new setup was designed and developed, so that the equilibrated samples can be quenched in oil directly under the same atmosphere inside the experimental setup. Three different phases were found in the samples, namely MgO, MgO-V₂O₃ spinel and V₂O₃. The phase boundaries were determined with good reproducibility. The solubility of V₂O₃ in the MgO phase increased with temperature and was significantly higher than literature data. The spinel as well as the V₂O₃ composition range were found to change only a little with temperature in the investigated temperature range. Decreased oxygen potential led to a slight increase of the V₂O₃ content in the spinel phase and V₂O₃ phase. Furthermore, decreased oxygen potential resulted in a significant increase of the solubility of V₂O₃ in the MgO phase at the higher temperatures, especially at 1873 K.     

(C_2H)_2M_n(M=Cu、Ag、Au;n=1-4)团簇的密度泛函理论研究

采用密度泛函理论的B3LYP和PBEIPBE方法,对(C_2H)_2M_n(M=Cu、Ag、Au;n=1-4)团簇的结构和性质进行了研究。结果表明:(C_2H)_2M_n(M=Cu、Ag、Au;n=1-4)簇的最稳定结构都是在C_2HM_n(M=Cu、Ag、Au;n=1-4)簇最稳定结构的基础上,又与C_2H自由基相互作用的结果。NBO计算结果表明:银与2个C_2H自由基的相互作用弱于铜和金。(C_2H)_2M_n(M=Cu、Ag、Au;n=1-4)簇最稳定结构的相互作用能均为负值,表明形成的团簇较稳定,并且出现了奇-偶振荡效应(n=1-4),含偶数个IB原子的团簇比含奇数个IB原子的团簇稳定。红外分析表明:(C_2H)_2M_n(M=Cu、Ag、Au;n=1-4)团簇中C_2H自由基的C≡C和C-H键的伸缩振动都发生了红移,随着团簇尺寸的增加(n=1-4),也出现了奇-偶振荡效应。     

Theoretical exploration to second-order nonlinear optical properties of new hybrid complexes via coordination interaction between (metallo)porphyrin and [MSiW11O39]3− (M = NbV or VV) polyoxometalates

The second-order nonlinear optical (NLO) properties of hybrid complexes via coordination interaction between porphyrin and Keggin-type polyoxometalates (POMs) α-[MSiW₁₁O₃₉]³⁻ (M = Nb^V or V^V) are investigated by time-dependent density functional theory (TDDFT). The calculated results show that this kind of organic–inorganic hybrid complexes possesses remarkably large molecular second-order NLO polarizability, especially for the ZnP₃P-CC-4-Py-[VSiW₁₁O₃₉]³⁻ (complex 4), which has a computed β₀ value of 261,410 a.u. and might be an excellent second-order NLO material. The effects of substituted metal atom (M), metalloporphyrin, and π-conjugation on NLO response are analyzed, the substituted metal atom (M) with a large electronegativity, the metalloporphyrin, and the lengthening of π-conjugation are helpful in enhancing the optical nonlinearity of these systems, which reveal the general rules to design the complexes with large optical nonlinearities. Furthermore, the solvent effect largely affects the first-order hyperpolarizability of the complex, it implies that the second-order polarizabilities increased with the increase of the solvent in polarity.     

N2O与HX(X=F,Cl,Br)分子间作用的电子密度拓扑研究

运用量子化学微扰理论MP2方法和密度泛函B3LYP方法,采用6-311++G(d,p)基组,对N_2O分子与HX(X=F,Cl,Br)分子形成的氢键复合物进行构型优化和能量计算。利用电子密度拓扑分析方法对氢键复合物的拓扑性质进行了分析,探讨了分子间氢键作用的本质。研究结果表明,N_2O分子与HX(X=F,Cl,Br)分子间可形成O…H-X和N…H-X 2类氢键;形成氢键后,作为电子受体的HX(X=F,Cl,Br)分子中的H-X键键长增加振动频率减小;氢键作用能按照NNO…HF、NNO…HCl、NNO…HBr和ONN…HF、ONN…HCl、ONN…HBr的顺序递减;氢键形成过程中存在从电子给体到电子受体的电荷转移。复合物体系中的氢键作用介于共价键和离子键之间,并且以静电作用为主。     

Determination of water activities,osmotic and activity coefficients of the system NH4NO3–LiNO3–H2O at the temperature 298.15 K

The water activities of the mixed aqueous electrolyte {(y) NH₄NO₃+(1−y) LiNO₃)}(aq) are measured at total molalities from 0.2 mol kg⁻¹ to about saturation for different ionic-strength fractions $y$ of NH₄NO₃ with $y=0.20,0.50,0.80$. The results allow the deduction of osmotic coefficients. The experimental results are compared with the predictions of the Zdanovskii–Stokes–Robinson (ZSR), Robinson and Stokes (RS), Lietzke and Stoughton (LS II), Reilly–Wood–Robinson (RWR) mixing rules and the Pitzer model. From these measurements, the Pitzer mixing ionic parameters are determined and used to predict the solute activity coefficients in the mixture. The excess Gibbs energy is also determined.     

H_2CX,(CH_2)_2 X(X=O,S)与氟分子间卤键复合物结构和性质的研究

为进一步了解卤键的作用本质,在MP2(full)/6-311++G(d,P)水平七,采用Ganssian 03量子化学软件包、AIM2000程序和电子密度拓扑分析程序GTA 2000,从理论上研究H2CX…F2,(CH2)2X…F2(X=0,S)分子间卤键复合物的结构和性质,计算和分析复合物的几何构型、分子间相瓦作用能、化学键的电子密度拓扑性质等.研究表明,H2CX,(CH2)2X(X=O,S)与F2间存在键鞍点,卤键的形成方向正好是O原子(或S原子)的电子密度浓集区伸展的方向;分子间卤键的形成伴随着F-F键键长的增加、振动频率的红移及电子密度拓扑性质的改变,复合物中的卤键介于共价键与离子键之间,偏于静电作用成分为主;析且H2CS,(CH2)2S与F2间作用强于H2CO,(CH2)2O与F2间的作用.     

Vasil’ev codes of length n = 2m and doubling of Steiner systems S(n, 4, 3) of a given rank

Extended binary perfect nonlinear Vasil’ev codes of length n = 2^m and Steiner systems S(n, 4, 3) of rank n-m over F ₂ are studied. The generalized concatenated construction of Vasil’ev codes induces a variant of the doubling construction for Steiner systems S(n, 4, 3) of an arbitrary rank r over F ₂. We prove that any Steiner system S(n = 2^m, 4, 3) of rank n-m can be obtained by this doubling construction and is formed by codewords of weight 4 of these Vasil’ev codes. The length 16 is studied in detail. Orders of the full automorphism groups of all 12 nonequivalent Vasil’ev codes of length 16 are found. There are exactly 15 nonisomorphic systems S(16, 4, 3) of rank 12 over F ₂, and they can be obtained from codewords of weight 4 of the extended Vasil’ev codes. Orders of the automorphism groups of all these Steiner systems are found.     

茂金属卡宾配合物{(eta5-C5H5)MoX(CO)2[C(CH2)2CH2O]}(X:Cl、Br、I)的电子结构研究

运用G98W程序，采用Lanl2dz基组，对藏金属配合物{（eta^5-C5H5)MoX(CO)2[C(CH2)2CH2O]}（X：Cl、Br、I）进行从头算研究，探讨配合物结构单元的稳定性、分子轨道能量、原子净电荷布居规律，以及一些前沿分子轨道的组成特征等。结果表明，标题配合物结构在能量上是稳定的，因而能作为结构单元而存在。为茂金属配合物的合成、分子组装提供理论参考。     

Composition-dependent interdiffusivity matrices in face centered cubic Ni–Al–X (X = Rh and W) alloys at 1423, 1473 and 1523 K: A high-throughput experimental measurement

Based on 18 face centered cubic (fcc) single-phase diffusion couples in ternary Ni–Al–X (X = Rh and W) systems together with the recently developed numerical inverse method, high-throughput measurements of the composition-dependent interdiffusivity matrices in fcc Ni–Al–X (X = Rh and W) alloys at 1423, 1473 and 1523 K were performed in the present work. Their reliability was comprehensively validated through comparison between the model-predicted composition/interdiffusion flux profiles for each diffusion couple and the corresponding experimental data. Moreover, the direct comparison with the interdiffusivities evaluated from traditional Matano-Kirkaldy method as well as those from the literature and in the boundary binary systems was also made. The errors for the determined interdiffusivities were evaluated by a scientific method considering the error propagation. The three-dimensional main interdiffusivity planes for fcc Ni–Al–X (X = Rh and W) systems over the investigated concentration ranges at 1423, 1473 and 1523 K were subsequently constructed. It was then found that ${\tilde{D}}_{AlAl}^{Ni}$ is generally larger than ${\tilde{D}}_{R\mathrm{h}Rh}^{Ni}$, while ${\tilde{D}}_{WW}^{Ni}$ is the smallest.     

Phase equilibria of the Al2O3–CaO–SiO2-(0%, 5%, 10%) MgO slag system for non-metallic inclusions control

Al₂O₃–CaO-(MgO–SiO₂) inclusions are one of the dominant inclusions in Al-deoxidized spring steel, the compositions changes of which are closely related to refining slags and deoxidization process. The Al₂O₃–CaO–SiO₂–MgO system can represent the primary ingredients of the Al₂O₃–CaO inclusions. According to analyzed compositions and predicted liquidus temperature ranges of inclusions and refining slag, equilibra experiments under high temperature, water quenching technique and subsquent electron probe X-ray microanalysis (EPMA) has been conducted to ascertain detailed thermodynamic database for inclusions control. Liquidus temperatures within the dominant phase fields of Ca₃SiO₅, Ca₂SiO₄, CaAl₂O₄, Ca₃Al₄O₉, spinel and MgO with the intervals of 20 °C from 1350 to 1560°C were identified. To further promote inclusions control, the influences of mass ratios of Mass(Al2O3)Mass(Al2O3+SiO2+CaO) and MgO contents on equilibrated phases and liquidus temperature changes have been explored. To further enhance modification levels of Al₂O₃–CaO-(MgO–SiO₂) system inclusions, it is suggested that refining time could be suitably prolonged.     

On resol vability of Steine r systems S( v = 2m, 4, 3) of rank r ≤ v − m + 1 o ve r $$\mathbb{F}_2 $$

Two new constructions of Steiner quadruple systems S(v, 4, 3) are given. Both preserve resolvability of the original Steiner system and make it possible to control the rank of the resulting system. It is proved that any Steiner system S(v = 2 ^m , 4, 3) of rank r ≤ v ? m + 1 over F₂ is resolvable and that all systems of this rank can be constructed in this way. Thus, we find the number of all different Steiner systems of rank r = v ? m + 1.     

Effect of CaO on the liquid/spinel/matte/gas equilibria in the Si–Fe–O–Cu–S system at controlled P(SO2) 0.3 and 0.6 atm

Herein the phase equilibria in the Si–Fe–Ca–O–S–Cu system in equilibrium with matte at controlled P(SO₂) of 0.3 and 0.6 atm and fixed matte grade of 72 wt % Cu were experimentally investigated in the spinel primary phase field. The high-temperature equilibrations were realized in spinel substrate and the sample after quenching were characterized using Electron Probe Micro-analysis (EPMA). The effect of CaO on the liquidus temperature of slags was quantified with varying CaO content from 0 to 6 wt %. It was found that, the presence of CaO increased the liquidus temperature of slags and moreover, the increment effect got enhanced with increasing CaO content in the present range. The influence of P(SO₂) was further clarified and it was found that, the equilibrium SiO₂ content in the liquid phase, at the same temperature, remarkably increased with increasing P(SO₂). The present study will not only deepen the understanding of the equilibration in the present liquid/spinel/matte/gas system, but also provide useful guidance for the industrial operations.