多环芳烃与不饱和自由基氢提取反应类的动力学研究

对2~6个环的多环芳烃的氢提取反应类进行了系统研究, 提取氢原子的不饱和自由基包括丙炔基自由基（C₃H₃）、 烯丙基自由基（C₃H₅）、 丁二烯基自由基（nC₄H₅, iC₄H₅）、 环戊二烯基自由基（C₅H₅）以及苯基自由基（C₆H₅）. 采用M06-2X/cc-pVTZ方法得到了多环芳烃的电子结构信息, 利用过渡态理论并结合Eckart隧道校正, 计算了所有反应在500~2500 K范围内的反应速率常数.考察了多环芳烃的大小、 结构对反应速率常数的影响, 对比了不同氢提取自由基及不同氢提取反应类型的速率常数. 结果表明, 多环芳烃的大小对反应速率常数影响不大, 但是多环芳烃的环结构对反应速率常数影响较大. 将不同的氢提取反应类简化为发生在五元环上的C₅类和发生在六元环上的C₆类两类, 结果表明, C₆类的反应活性高于C₅类. 研究了nC₄H₅, iC₄H₅以及C₆H₅自由基与多环芳烃的氢提取反应, 它们的氢提取反应活性大小顺序为C₆H₅>nC₄H₅>iC₄H₅. 通过对每类典型反应的速率常数取平均值, 总结出相应类型的速率规则, 可用于构建多环芳烃和碳烟机理.     

过渡金属配合物的13C-NMR化学位移计算

基于X_α-SW法数值波函数,从微扰理论出发,计算了过渡金属配合物中CO、CS、CN和C₅H₅配体中的¹³C核磁共振顺磁化学位移σ_p及反磁性化学位移σ_d贡献.结果能反映实验趋势,并从电子结构及成键角度进行了讨论.     

Theoretical study on reaction mechanism of the vinyl radical with nitrogen atom

The complex triplet potential energy surface of the C₂H₃N system is investigated at the UB3LYP and CCSD(T) (single-point) levels in order to explore the possible reaction mechanism of C₂H₃ radical with N(⁴S). Eleven minimum isomers and 18 transition states are located. Possible energetically allowed reaction pathways leading to various low-lying dissociation products are obtained. Starting from the energy-rich reactant C₂H₃+N(⁴S), the first step is the attack of the N atom on the C atom having one H atom attached in C₂H₃ radical and form the intermediate C₂H₃N(1). The associated intermediate 1 can lead to product P₁ CH₂CN+H and P₂ ³CH₂+³HCN by the cleavage of C–H bond and C–C bond, respectively. The most favorable pathway for the C₂H₃+N(⁴S) reaction is the channel leading to P₁, which is preferred to that of P₂ due to the comparative lower energy barrier. The formation of P₃ ³C₂H₂+³NH through hydrogen-abstraction mechanism is also feasible, especially at high temperature. The other pathways are less competitive comparatively.     

New organogold(I) complexes: Synthesis, structure, and dynamic behavior of the polynuclear organogold diphenylmethane and diphenylethane derivatives

Two organogold derivatives of diphenylmethane and diphenylethane, Ph₃PAu(o-C₆H₄)CH₂(C₆H₄-o)AuPPh₃ (1) and Ph₃PAu(o-C₆H₄)(CH₂)₂(C₆H₄-o)AuPPh₃ (2), have been synthesized by the reaction of ClAuPPh₃ with Li(o-C₆H₄)CH₂(C₆H₄-o)Li and Li(o-C₆H₄)(CH₂)₂(C₆H₄-o)Li respectively. The interaction of 1 with dppe results in the replacement of the two PPh₃ groups to give a macrocyclic compound (3) that includes an Au Au bond. Compounds 1 and 2 react with one or two equivalents of [Ph₃PAu]BF₄ to form new types of cationic complex [CH₂(C₆H₄-o)₂(AuPPh₃)₃]BF₄ (4), [CH₂(C₆H₄-o)₂(AuPPh₃)₄](BF₄)₂ (5), and [(CH₂)₂(C₆H₄-o)₂(AuPPh₃)₄](BF₄)₂ (6). Complexes 1–6 have been characterized by X-ray diffraction studies, FAB MS, and IR as well as by ¹H and ³¹P NMR spectroscopy. A complicated system of Au H-C agostic interactions, involving the bridging alkyl groups (—CH₂— and CH₂-CH₂—) of diphenylmethane and diphenylethane ligands, has been found to occur in complexes 1–3 and 6.     

Syntheses of heterocyclic compounds—I Cyclization of N-substituted O-nitroanilines

Internal cyclization of a nitrogroup was carried out by heating the N-substituted o-nitroanilines (I; R=C₆H₁₁---, C₆H₅.CH₂, C₆H₅.CH₂.CH₂---, X=NH) in the presence of ferrous oxalate¹ (Waterman and Vivian's method) as a potential route to partly hydrogenated nitrogen heterocycles. A mechanism for this type of ring-closure is proposed.     

Crystal structure of the 1/ 1 molecular complex of 5,5′,12,12′-bis(triseleno)bis(naphthacene-6,11-quinone) with benzonitrile, (C18H8Se3O2)2(C6H5CN)

The structure of the (C₁₈H₈Se₃O₂)₂(C₆H₅CN) molecular complex isolated from the TSeT + HgI₂ reaction in benzonitrile has been determined. The -Se-Se-Se- fragment has been found to have Se---Se bond lengths equal to 2.348(3) and 2.350(4) Å.     

N-苄基-N-(2-氰乙基)-二茂铁磺酰胺的晶体和分子结构

N-等基-N-(2-氰乙基)-二茂铁磺酰胺[C₅H₅FeC₅H₄SO₂N(C₂H₄CN)CH₂C₆H₅]为黄色柱状晶体,属单斜晶系,空间群P2₁/n,晶胞参数为:α=8.750(1),b=12.876(5),c=16.744(2)Å,β=94.75(1)°,V=1880.0ų,Z=4,计算密度D_calc=1.442g/cm³。在CAD-4四园衍射仪上,用MoK_α射线收集衍射数据,用Patterson函数法和差值Fourior合成求解晶体结构。经以2226个独立衍射点用全矩阵最小二乘修正,最后使偏离因子R=0.0466.分子中S原子、N原子以不等性sp³杂化与周围原子健合。     

Systematische untersuchungen über das verhalten von organozinnverbindungen gegenüber flüssigem schwefeldioxid II. Reaktionen von arylstannanen mit flüssigem SO2

The behaviour of tetraarylstannanes, R₄Sn (R = C₆H₅CH₂, C₆H₅, o-, m-, p-CH₃C₆H₄), towards SO₂ under various conditions has now been studied in detail. Compared to aliphatic tetraorganostannanes, the variability of the reaction products is much less, so that in nearly all cases only disulfinates, R₂Sn(O₂SR)₂, are formed. The aromatic tin(IV) mono-, di- and tri-sulfinates are also obtained by metathetical reaction between the corresponding organotin halides and sodium sulfinates. A unique feature of triaryltin chlorides, R₃SnCl (R = C₆H₅, o-, m-, p-CH₃C₆H₄), is their disproportionation in liquid SO₂ leading to disulfinates, R₂Sn(O₂SR)₂, and dichlorides, R₂SnCl₂. (p-CH₃C₆H₄)₂SnCl₂, under more efficient conditions, also accepts SO₂ forming (p-CH₃C₆H₄SO₂)₂SnCl₂. The structural investigations of the newly prepared compounds are carried out on the basis of their IR and ¹H NMR spectra.     

Substituent effects on the frontier molecular orbitais of aryl isonitriles

An investigation of the frontier molecular orbitais ofo- and p-RC₆H₄NC (R=H, CH₃, NO₂, F, Cl, CF₃, OCH₃) was carried out so that a thorough understanding of the intricacies of σ donation and π acceptance could be developed and used to modify subtly the electron density on metal centers. The results of this study-Indicate that the substituent position (ortho vs. para ) does alter the electron density in the ligand appreciably and that substitution of the phenyl ring with the groups indicated has a smaller effect on the σ-donating ability than it does on the π-accepting ability of the isonitrile ligand.

The π-accepting abilities of the isonitrile ligands increase in the order o-, p-CH₃OC₆H₄NC, o-, p-CH₃C₆H₄NC, o-, p-C₆H₅NC, o-, p-FC₆H₄NC, o-, p-CF₃C₆NC, o-, p-ClC₆H₄NC, o-, p-NO₂C₆H₄NC while the σ-donating ability decreases in this order. The energies of the σ-donor and π-acceptor orbitais are shown to correlate well with observed E values of Cr(RC₆H₄NC)₆ and Mn(RC₆H₄NC)₆⁺¹ complexes. This demonstrates how the theoretical results can be useful in understanding the observed physical properties of isonitrile-metal complexes.     

以苯荒酸为配体的[Bu4N]2[W2Ag3S8(C6H5CSS)]钨银硫簇合物的合成和晶体结构

标题化合物由(C₆H₅CSS)^-(Bu₄N)⁺、AgNO₃和(NH₄)₂WS₄、Bu₄NBr反应制备,用X射线单晶衍射法测定其晶体结构。     

New heterodimetallic cyclopentadienyl carbonyl complexes: crystal structure of (C5Me4Et)(μ-CO)3Ru(C5Me5)

A series of heterodimetallic complexes of general formula (C₅R₅)M(μ-CO)₃RuC₅Me₅ (M = Cr, Mo, W; R = Me, Et) has been prepared in good yields by the reaction of [C₅R₅M(CO)₃]⁻ with [C₅Me₅Ru(CH₃CN)₃]⁺. (C₅Me₄Et)W(μ-CO)₃Ru(C₅Me₅) was characterized by a crystal structure determination. The W---Ru bond length of 2.41 Å is consistent with the formulation of a metal-metal triple bond, while the unsymmetrical bonding mode of the three bridging carbonyl groups reflects the inherent non-equivalence of the two different C₅R₅M-units. Using [CpRu(CH₃CN)₃]⁺ or [CpRu(CO)₂(CH₃CN)]⁺ as the cationic precursor leads to the formation of dimetallic species (C₅R₅)M(CO)₅RuC₅H₅ with both bridging and terminal carbonyl groups.     

Synthesis of 2,7-dihydro-3,4-5,6-dibenzotellurepin—a new heterocyclic compound

The reaction of 2,2-bis(bromomethyl)biphenyl with tellurium powder and sodium iodide gave the orange compound 1,1-diiodo-2,7-dihydro-3,4-5,6-dibenzotellurepin (1), which is easily reduced with hydrazine hydrate to 2,7-dihydro-3,4-5,6-dibenzotellurepin (2). The latter compound readily forms a black-brown 1:1 complex with TCNQ. The former could be converted to its 1,1-bis(diethyldithiocarbamato)-2,7-dihydro-3,4-5,6- dibenzotellurepin (3) and 1-phenyl-2,7-dihydro-3,4-5,6-dibenzotellurepinium tetraphenylborate (4), respectively, by treatment with NaS₂CN(C₂H₅)₂ and NaB(C₆H₅)₄. The UV-vis, IR, ESR and ¹H NMR spectral data for the new compounds are presented and discussed.     

Synthesis, electrochemistry and structural characterization of luminescent rhenium(I) monoynyl complexes and their homo- and hetero-metallic binuclear complexes

A series of luminescent rhenium(I) monoynyl complexes, [Re(N---N)(CO)₃(CC---R)] (N---N=bpy, ^tBu₂bpy; R=C₆H₅, C₆H₄---Cl-4, C₆H₄---OCH₃-4, C₆H₄---C₈H₁₇-4, C₆H₄---C₆H₅, C₈H₁₇, C₄H₃S, C₄H₂S---C₄H₃S, C₅H₄N), together with their homo- and hetero-metallic binuclear complexes, {Re(N---N)(CO)₃(CC---C₅H₄N)[M]} (N---N=bpy, ^tBu₂bpy; [M]=[Re{(CF₃)₂-bpy}(CO)₃]ClO₄, [Re(NO₂-phen)(CO)₃]ClO₄, W(CO)₅) have been synthesized and their electrochemical and photoluminescence behaviors determined. The structural characterization and electronic structures of selected complexes have also been studied. The luminescence origin of the rhenium(I) alkynyl complexes has been assigned as derived states of a [dπ(Re)→π*(N---N)] metal-to-ligand charge transfer (MLCT) origin mixed with a [π(CCR)→π*(N---N)] ligand-to-ligand charge transfer (LLCT) character. The assignments are further supported by extended Hückel molecular orbital (EHMO) calculations, which show that the LUMO mainly consists of π*(N---N) character while the HOMO is dominated by the antibonding character of the Re---CCR moiety resulted from the overlap of the dπ(Re) and π(CCR) orbitals.     

2,4-二硫代尿嘧啶的紫外吸收光谱和共振拉曼光谱

硫代嘧啶碱基是光动力疗法潜在的重要光敏剂,其最低单重激发态的光物理研究已有广泛报道。然而,其较高激发态的跃迁性质和反应动力学研究较为稀少。因此,本文采用共振拉曼光谱和密度泛函理论计算方法研究2,4-二硫代尿嘧啶的紫外光谱和几个较高单重激发态的短时结构动力学。首先,基于共振拉曼光谱强度与电子吸收带振子强度f的关系,将紫外光谱去卷积成四个吸收带,分别为358 nm(f=0.0336)中等强度吸收带(A带),338 nm(f=0.1491)、301 nm(f=0.1795)和278 nm(f=0.3532)强而宽的吸收带(B、C和D带)。这一结果既吻合密度泛函理论计算结果,又符合共振拉曼光谱强度模式对紫外光谱带的预期。据此,去卷积得到的四个吸收带被分别指认为S0→S2跃迁、S0→S6跃迁、S0→S7跃迁和S_0→S_8跃迁。同时,分别对B,C和D带共振拉曼光谱进行了详细的指认,获得了短时动力学信息。结果表明,S_8态短时动力学的显著特征是在Franck-Condon区域或附近发生了S8(ππ~*)/S(nπ~*)势能面交叉引发的、伴随超快结构扭转的非绝热过程。S7和S6态短时动力学的主要特征是反应坐标的多维性,它们分别沿C_5C_6/C_2S_8/C_4S_(10)/N_2C_3+C_4N_3H_9/N_1C_2N_3/C_2N_1C_6/C_6N_1H_7/C_5C_6H_(12)和C_5C_6/N_3C_2/C_4S_(10)/C_2S_8+C_6N_1H_7/C_5C_6H_(12)/C_5C_6N_1/C_5C_6H_(12)/C_2N_1C_6/N_1C_2N_3/C_4N_3H_9/N_1C_2N_3等内坐标演化。     

Spectres de rotation de la molécule de chlorobenzène : II. Variétés isotopiques multisubstituées et structure géométrique précise

In order to complete the r_s structure of chlorobenzene given in a preceding paper, a variety of isotopic species of this molecule were synthesized and their microwave spectra studied. This made twenty isotopic species available, enabling the determination of the geometrical parameters by a least squares method. Fitting only differences of moments of inertia either for monosubstituted species or to multiply substituted species gave the same result. They hardly differ from the r_o values and agree with the r_s values obtained by the Kraitchman equations. The resulting error limits were reduced, however.

The following structural parameters were obtained, C₁C₂ = 1.399 Å, C₂C₃ = 1.386 Å, C₃C₄ = 1.3976 Å, C₁Cl = 1.7248 Å, C₂H₂ = 1.080 Å, C₃H₃ = 1.081 Å, C₄H₄ = 1.081 Å, C₆C₁C₂ = 120° 16, C₁C₂C₃ = 119°78, C₂C₃C₄ = 120°24, C₃C₄C₅ = 119°80, C₁C₂H₂ = 119°45, C₂C₃H₃ = 119°76.

The structure of the ring differs significantly from C₆ symmetry. The deformation can be regarded as a compression of the position C₁ while the angle of C₂H₂ bond is also changed.     

Ultrafast dissociation dynamics of ketones at 195 nm

The photodissociation dynamics of the 3s Rydberg state of three ketones (CH₃CO–R, R=C₂H₅, C₃H₇, and iso-C₄H₉) and the ensuing dissociation of the nascent acetyl radical following 195 nm excitation were investigated by ultrafast photoionization spectroscopy. The 3s state the lifetimes of these ketones are similar (2.5–2.9 ps), though lifetimes of the acetyl radical range from 8.6 ps for CH₃CO–C₂H₅, 15 ps for CH₃CO–C₃H₇, to 23 ps for CH₃CO–(iso-C₄H₉), which suggests that for larger R more vibrational degrees of freedom compete for the excess energy so that less energy is partitioned into the internal energy of the acetyl radical.     

Synthese und reaktivität von dienylmetall-verbindungen : XXVII. Ein einfacher weg zur synthese von cyclopentadienylcobalt(III)-dikationen

CpCo(CO)₂ is oxidised by [Cp₂Fe]BF₄ (Cp = C₅H₅) in the presence of neutral ligands L to give the dications [CpCoL₃]²⁺ (L = SMe₂, S(n-C₄H₉)₂, PMe₃, C₅H₅N, MeCN; Me = CH₃). In [CpCo(SMe₂)₃]²⁺, sulfane ligands are substituted by neutral ligands L, L---L and L---L---L, to give the complexes [CpCoL₃]²⁺ (L = SeMe₂, TeMe₂, PMe₃, P(OMe)₃, AsMe₃, SbMe₃, t-C₄H₉NC, C₅H₅N, MeCN), [Cp-Co(L---L)SMe₂]²⁺ (L---L = R₂P(CH₂)_nPR₂, n = 1, 2, R = C₆H₅; bipyridine, o-phenanthroline, neocuproin) and [CpCo(L---L---L)]²⁺ (L---L---L = RP(CH₂CH₂PR₂)₂, R = C₆H₅). The dications react with iodide resulting in the monocations [CpCoL₂I]⁺ and [CpCo(L---L)I]⁺. Azacobaltocinium cations [CpCo(C₄R₂H₂N)]⁺ (R = H, CH₃) are obtained by reaction of [CpCo(SMe₂)₃]²⁺ with metal pyrrolides.     

Synthesis and structural characterization of mixed ligand η-2-hydroxyacetophenone complexes of cobalt(III)

A tridentate Schiff base ligand [(CH₃)₂NCH₂CH₂N=C(CH₃)C₆H₄OH)] (LH) has been synthesized from 2-hydroxyacetophenone and 2-dimethylaminoethylamine. This ligand forms the neutral complexes [Co(L)(N₃){o-(CH₃C=O)C₆H₄O}] (1) and [Co(L)(SCN){o-(CH₃C=O)C₆H₄O}]·1/2H₂O (2) in presence of equivalent amount of Co(II) acetate, and sodium azide for 1 and sodium thiocyanate for 2. The complexes have been characterized by spectroscopic and crystallographic methods. The coordination geometry around Co(III) in both the complexes is distorted octahedral with one tridentate ligand L, one bidentate 2-hydroxyacetophenone and one monodentate azide for 1 and thiocyanate for 2. The azide and thiocyanate ligands in the two complexes occupy different positions relative to the coordination sites of L.     

A STUDY OF THE REDOX CHARACTERISTICS OF THE TERNARY CLATHRATE COMPOUND Mo[S2CN(C2H5)2]4}+{FeCl4}-C6H5CH2SSCH2C6H5

The redox characteristics of the ternary clathrate compound {Mo[S₂CN(C₂H₅)₂]₄}⁺{C₆H₅CH₂SSCH₂C₆H₅}^-was studied by electrochemical measurement and quantum-chemical calculations.The cyclic voltammogram of this ternary clathrate compound in 0.1M KClO₄-DMF with a platinum electride had 2.pairs of redox peak.Both the electrochemical parameters derived from the voltammogram and the results of EHMO calculations indicate that the pair of redox peak at relatively positive potentials corresponds to the redox reaction of Fe(Ⅲ)/Fe(Ⅱ) which is irreversible in nature,while the pair of redox peak at more negative potentials corresponds to the redox reaction of Mo(Ⅴ)/ Mo(Ⅱ) which is semi-reversible.The calculations from experiment measurements are fairly agreement with the theoretical calculations.     

苯甲醛及对溴苯甲醛光解初级过程自由基的ESR研究

苯甲醛的光解与其在放置过程中的自氧化引发机理密切相关,因此确定光解过程的主要中间产物有重要意义。自氧化的全过程比较复杂,但单纯的光解本身显然相对简单一些。本文用自旋捕捉-ESR技术研究了苯甲醛及与其相类似的对溴苯甲醛在紫外和可见光作用下生成的活泼中间体,并讨论了在本文实验条件下的光解初级过程。