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1.
(BN)n(n≤12)团簇的结构及成键性质 总被引:6,自引:0,他引:6
利用遗传算法和Gastreich提出的经验势函数研究了(BN)n(n≤12)团簇的可能稳定结构, 并对能量较低的异构体在HF/6-31G(d)水平进行优化, 得到了(BN)n(n≤12)团簇的线状、蒲扇形、单环、双环、三环和笼状结构, 讨论了各种结构的特征及相对稳定性. 分析了BN团簇中原子的成键性质, 在单环结构中, N原子以sp2杂化成键, B原子以sp杂化成键, 而在节点处B原子以sp2杂化成键. (BN)6是唯一没有张力的单环结构. 相似文献
2.
以高纯氮气为载气,通过532nm的激光轰击由Ti、BN粉末混合压制成的样品,生成了钛氮团簇,确定了最稳定钛氮团簇的组成为TiN12。以四氟化钛和三甲基叠氮硅烷为原料,在液氮冷却下开展了钛氮团簇的化学法合成,对所得产物进行了IR、NMR表征,确定其结构为Ti(N3)4。用密度泛函理论(DFT)对TiN12的结构进行了优化,发现存在一种Ti(N3)4形式的具有对称的正四面体结构的稳定构型,这与化学法合成的TiN12的IR和NMR谱相符。不过,仍需进一步确定激光轰击法和化学合成法产生的TiN12是否具有相似的结构。 相似文献
3.
以高纯氮气为载气,通过532nm的激光轰击由Ti、BN粉末混合压制成的样品,生成了钛氮团簇,确定了最稳定钛氮团簇的组成为TiN12。以四氟化钛和三甲基叠氮硅烷为原料,在液氮冷却下开展了钛氮团簇的化学法合成,对所得产物进行了IR、NMR表征,确定其结构为Ti(N3)4。用密度泛函理论(DFT)对TiN12的结构进行了优化,发现存在一种Ti(N3)4形式的具有对称的正四面体结构的稳定构型,这与化学法合成的TiN12的IR和NMR谱相符。不过,仍需进一步确定激光轰击法和化学合成法产生的TiN12是否具有相似的结构。 相似文献
4.
用杂化密度泛函B3LYP方法研究了(AB)8(AB=BN,AlP,GaAs,InSb)团簇环形结构的平衡几何构型、电子结构、振动特性以及极化率。计算结果表明,(AB)8团簇的双层环状结构中,每个A(B)原子都与3个B(A)原子成键,且Ⅴ族元素的原子比Ⅲ族元素的原子更接近团簇中心,(BN)8、(AlP)8、(GaAs)8、(InSb)8的平均极化率依次增大,IR和Raman谱峰发生红移。另外,讨论了热力学稳定性和动力学稳定性的变化。 相似文献
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运用广义梯度近似(GGA)密度泛函理论的Perdew-Burke-Ernzerh (PBE)方法, 研究了肉桂醛在正二十面体Au13和Pt13团簇上的吸附行为. 通过分析不同吸附模式的吸附能和几何构型发现: 同一金属团簇, 顺式肉桂醛的吸附能强于反式肉桂醛的吸附能. 对于Au13团簇, 肉桂醛的稳定吸附构型为C=C和C=O共吸附模型; 对于Pt13团簇, 肉桂醛的稳定吸附构型为C=O吸附. 比较二者发现, 肉桂醛在Pt13团簇的吸附能力强于Au13团簇.分析Au13和Pt13团簇上肉桂醛最稳定吸附构型的电子结构表明, 电子由肉桂醛原子的2s、2p轨道向金属表面转移, 同时金属部分电子反馈到肉桂醛的反键轨道, 最终肉桂醛稳定吸附于金属团簇. 此外, 肉桂醛在团簇模型上的吸附能大于其在平板模型上的吸附能. 相似文献
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金-硫团簇负离子组成特征的探讨 总被引:3,自引:0,他引:3
报导了金/硫靶在静态二次离子质谱实验条件下形成的组成通式为Au1-15S0-5的团簇负离子.其中,Aun组成系列具有典型的奇数优势,属于金的一元团簇负离子.其余组成系列(Au1-15S1-5)则属于金 硫二元团簇负离子.研究发现,金 硫团簇负离子具有以下与组成密切相关的特征: (1)它们继承了金一元团簇负离子的奇数优势;(2)它们中硫原子数仅限于5,而金原子数则在较大范围变化;(3)它们完全没有多数其它金属与非金属(包括硫)二元团簇正/负离子共有的MenNn型组成优势;(4)它们以上组成特征及其它细节恰似碳 磷这样的典型非金属二元团簇正/负离子.基于这样的组成特征可提出,金 硫团簇负离子在构成上包含着相对完整的金一元团簇组件,在形成机制上源于金一元团簇与硫一元团簇(或称为:限于五原子的多硫单元)之间的再团簇化.关于再团簇化机制中的相互作用问题,即两类团簇间是依靠末端原子交叉成键还是依赖两类团簇中异种原子之间静电诱导力等“非共价键”作用的问题,则有待于今后研究证实. 相似文献
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A regular polyhedron is isomorphic to a cluster on which every face has same number of bonds and every atom has an equal number of coordinating atoms. A general strategy for generating the eigenvectors and the eigenvalues of regular polyhedra is given. Not sign analyses are also performed on the eigenvectors of regular polyhedra. The results provide us a quick way to grasp the topological feature of the electronic structure of clusters having interesting topology. 相似文献
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新颖四核W-Cu-S簇合物[(η5-C5Me5)WS3Cu3Br(Py)3(dppm)](PF6)的合成和晶体结构 总被引:1,自引:0,他引:1
In the presence of NH4PF6, reaction of [PPh4][(η5-C5Me5)WS3Cu3Br(dppm)] with excess pyridine afforded red prismatic crystals, [(η5-C5Me5)WS3Cu3Br(Py)3(dppm)](PF6) (1). It was characterized by elemental analy-sis, IR, UV-vis and 1H NMR spectroscopy and X-ray diffraction. 1 crystallizes in an orthorhombic system with space group Pna21 and unit cell parameters a=2.1124(4)nm, b=1.8944(4)nm, c=1.3338(2)nm, V=5.3375(19)nm3, Z=4, Dc=1.807g·cm-3,Mr=1452.42, F(000)=2864, μ=4.342mm-1, R1=0.0487, wR2=0.1027. The structure of the cluster cation contains an incomplete cubane-like WS3Cu3 core where Cu(1) and Cu(2) atoms are bridged by a dppm ligand. Each of the three Cu atoms adopts a distorted tetrahedral coordi-nation geometry. The W-Cu(1), W-Cu(2) and W-Cu(3) distances are 0.27698(17)nm, 0.2772(17)nm, and 0.27065(9)nm, respectively. CCDC: 199845. 相似文献
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新型六核双网兜状簇合物[MoS_4Cu_5Br_3(Py)_7]的合成与晶体结构 总被引:1,自引:0,他引:1
以(NH4)2[Mo2S12]?H2O与过量CuBr在吡啶溶液中反应,得到了一个新型六核Mo/Cu/S簇合物[MoS4Cu5Br3(Py)7]。X-射线单晶结构分析表明它属于三斜晶系,空间群为P?C35H35Br3Cu5MoN7S4,Mr=1335.37,a=11.6274(4),b=12.0127(4),c=18.8872(5),a=82.46(2),b=73.25(2),g=62.800(13),V=2246.8(2)?,Z=2,F(000)=1300.0,Dc=1.974g/cm3,?=5.482mm-1,5718个独立可观察点(I>3(I)),最终偏离因子R和Rw分别为0.042和0.048。标题化合物是由2个相似的网兜状MoS3Cu3簇核通过共用MoSCuS平面形成的双网兜状结构,Mo…Cu距离在2.6830(11)~2.741(2)胖洹? 相似文献
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Jeffrey J. Toman Arthur A. Frost Sid Topiol Solomon Jacobson Mark A. Ratner 《Theoretical chemistry accounts》1981,58(4):285-294
Ab initio FSGO-pseudopotential studies are reported for the nine molecules M(LH3)4; M, L = C, Si, Ge. We report orbital energies, calculated geometries, bonding parameters, and predicted energies of reaction.
Comparison with experimental data shows the results to be quite satisfactory. Comparison with the tetrahedral group IV solids
affords some clues to the nature of the doped materials. The outstanding observation, from all parameters calculated, is the
similarity of (Si, Ge) and their difference from carbon. Comments on possible stability of the compounds are ventured. 相似文献
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以2[(η5-C5Me5)WS3(CuBr)3]2和diphenyl-2-pyridylphosphine (PPyPh2)在乙腈中反应得到标题化合物[(η5-C5Me5)WS3Cu3Br2(PPyPh2)2], 对该产物进行了元素分析、 IR、 UV-Vis和1H NMR 谱表征, 并测定了晶体结构. 该化合物晶体属三斜晶系, P1空间群, 晶胞参数: a=1.545 9(7) nm, b=1.62 0(1) nm, c=1.018 0(2) nm, α=94.18(3)°, β=97.38(3)°, γ=111.81(4)°, V=2.327(2) nm3, Z=2, Dc=1.84 g*cm-3, F(000)=1 260, μ=57.77 cm-1, 最终偏离因子R=0.029. 此簇合物结构可视为由一个[(η5-C5Me5)WS3]单元和3个Cu组成的开口立方烷, 其中2个Cu是畸变四面体配位, 第3个Cu是近似三角平面配位. W-Cu(1), W-Cu(2) 和W-Cu(3)距离分别为0.270 41(9), 0.273 27(8), 0.267 85(9) nm. 相似文献
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IntroductionThechemistryofthethiometallateanionsiscurrentlyasubjectofintenseinterestduetotheirrichstructuraldi versity ,1 8theirrelevancetoindustrialcatalyticprocess9,10andmetalloenzymes ,11,12 andtheirpotentialutilityasnon linearopticalmaterials .13 16Wehaverep… 相似文献
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Atomic clusters characterized by finite size, low dimensionality, and reduced coordination number exhibit many novel properties that are very different from their bulk. As these clusters are assembled, their properties can be significantly altered due to the interaction of these clusters with each other as well as with their support. This paper provides a brief review of the cluster properties that are affected when clusters are deposited on metallic or organic substrates, isolated in matrices or in zeolite cages, coated with acetate ligands, or simply allowed to self-assemble without the presence of any reactive species. It is shown that the interface between the clusters and their support can play an important role on the properties of clusters as their unique characteristics do. 相似文献
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Reactions of [(dtc)2Mo2(S)2(μ-S)2] with one or two equivalents of CuBr in CH2Cl2 afforded two new heterobimetallic sulfide clusters, [(dtc)2Mo2(μ3-S)(μ-S)3(CuBr)] (1) and [(dtc)2Mo2(μ3-S)4(CuBr)2] (2). Both compounds were characterized by elemental analysis, IR, UV-vis and X-ray analysis. Compound 1 contains a butterfly-shaped Mo2S4Cu core in which one CuBr unit is coordinated by one bridging S and two terminal S atoms of the [(dtc)2Mo2(S)2(μ-S)2] moiety. In the structure of 2, one [(dtc)2Mo2(S)2(μ-S)2] moiety and two CuBr units are held together by six Cu-μ3-S bonds, forming a cubane-like Mo2S4Cu2 core. 相似文献
19.
Daniele Cauzzi Claudia Graiff Chiara Massera Giovanni Predieri Antonio Tiripicchio 《Journal of Cluster Science》2001,12(1):259-271
The reaction of [Ru3(CO)12] with Ph2(pyth)PSe (pyth=5-(2-pyridyl)-2-thienyl) allows to obtain two novel clusters [Ru3(3-Se)2(CO)7{P(pyth)Ph2}2] 1 and [Ru3(3-Se)(-PPh2)(-pyth)(CO)6{P(pyth)Ph2}] 2 in satisfactory yields. The first one exhibits the well-known bicapped, open triangular, 50-electron nido-core, whereas 2, whose crystal structure has been determined, shows the rather rare Ru3Se tetrahedron with the Ph2P and pyth fragments as side-bridging ligands. Morever cluster 2 belongs to the exiguous family of selenido-phosphido clusters not easily achievable by other routes. 相似文献
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合成了四个三核簇合物[A]2[MS4(CuCN)2](1A=Et4N,M=Mo;2A=PPh4,M=W;3A=Et4N,M=W;4A=PPh4,M=Mo),测定了[Et4N]2[MoS4(CuCN)2]*H2O(1*H2O)和[PPh4]2[WS4(CuCN)2]*0.5DMF*H2O(2*0.5DMF*H2O)的晶体结构.1和2的簇阴离子[MS4(CuCN)2]2-(M=Mo,W)均具有一个双齿配体MS42-和两个CuCN形成的近似D2d对称性结构. 相似文献