Gold as hydrogen: structural and electronic properties and chemical bonding in Si3Au3(+0-) and comparisons to Si3H3(+0-)

A single Au atom has been shown to behave like H in its bonding to Si in several mono- and disilicon gold clusters. In the current work, we investigate the AuH analogy in trisilicon gold clusters, Si3Au3(+0-). Photoelectron spectroscopy and density functional calculations are combined to examine the geometric and electronic structure of Si3Au3-. We find that there are three isomers competing for the ground state of Si3Au3- as is the case for Si3H3-. Extensive structural searches show that the potential energy surfaces of the trisilicon gold clusters (Si3Au3-, Si3Au3, and Si3Au3+) are similar to those of the corresponding silicon hydrides. The lowest energy isomers for Si3Au3- and Si3Au3 are structurally similar to a Si3Au four-membered ring serving as a common structural motif. For Si3Au3+, the 2pi aromatic cyclotrisilenylium auride ion, analogous to the aromatic cyclotrisilenylium ion (Si3H3+), is the most stable species. Comparison of the structures and chemical bonding between Si3Au3(+0-) and the corresponding silicon hydrides further extends the isolobal analogy between Au and H.     

Theoretical investigation of the structure and coverage of the Si(111)-OCH3 surface

The surface structure, strain energy, and charge profile of the methoxylated Si(111) surface, Si(111)-OCH3, has been studied using quantum mechanics, and the results are compared to those obtained previously for Si(111)-CH3 and Si(111)-C2H5. The calculations indicate that 100% coverage is feasible for Si(111)-OCH3 (similar to the methylated surface), as compared to only approximately 80% coverage for the ethylated surface. These differences can be understood in terms of nearest-neighbor steric and electrostatic interactions. Enthalpy and free energy calculations indicate that the formation of the Si(111)-OCH3 surface from Si(111)-H and methanol is favorable at 300 K. The calculations have also indicated the conditions under which stacking faults can emerge on Si(111)-OCH3, and such conditions are contrasted with the behavior of Si(111)-CH3 and Si(111)-CH2CH3 surfaces, for which stacking faults are calculated to be energetically feasible when etch pits with sufficiently long edges are present on the surface.     

Density functional theory study on fundamental vibrational spectra of disilyl iodide and its isotopomer

Density function theory calculations using B3' exchange functional and LYP' correlation functionals (B3LYP) with the 3-21G** basis set were carried out to study the molecular structure and fundamental vibrational frequencies of Si2H5Br, Si2H5I and their isotopomers. One scale factor used to scale Si-H(D) force constants for Si2H5Br is transferred from Si2H5Br to Si2H5I. Other scale factors of force constants for Si2H5I and Si2D5I are determined by a least-squares fitting to experimental vibrational frequencies. The predictions of fundamental vibrational frequencies for Si2H5I and its isotopomer are given. The scaled DFT force fields using B3LYP/3-21G** reproduced the observed fundamental vibrational frequencies of Si2H5I and its deuterium isotopomer with a mean absolute deviation of 6 cm(-1). Reassignment of some fundamental vibrational modes of Si2H5I and its isotopomer is discussed.     

1,3-Migration of Trimethylsilyl Group from Carbon to Oxygen in Highly Sterically Hindered Silanol of the Type (Me 3 Si) 3 CSi(C 6 H 4 Me- p )MeOH and Reaction of the Related Iodide with Iodine Monochloride and Iodine Monobromide

The silanol (Me 3 Si) 3 CSi(C 6 H 4 Me- p )MeOH has been shown to isomerize to (Me 3 Si) 2 CHSi(C 6 H 4 Me- p )(Me)(OSiMe 3 ) when it was kept at room temperature for 10 h in 0.2 M NaOMe/MeOH. Corresponding isomerizations of the above silanol (to give (Me 3 Si) 2 CHSi(C 6 H 4 Me- p ) (Me)(OSiMe 3 )) are complete after 26 h under reflux in pyridine. The reaction involve 1,3-migration from carbon to oxygen within a silanolate ion to give a carbanion, which rapidly acquires a proton from the solvent. Treatment of (Me 3 Si) 3 CSi(C 6 H 4 Me- p )MeOH with MeLi in Et 2 O/THF give, by the same rearrangement, the organolithium reagent (Me 3 Si) 2 CLiSi(C 6 H 4 Me- p )(Me)(OSiMe 3 ) which on treatment with Me 2 SiHCl gives (Me 3 Si) 2 C(SiMe 2 H)Si(C 6 H 4 Me- p )(Me)(OSiMe 3 ) and (Me 3 Si) 2 CHSi(C 6 H 4 Me- p )(Me)(OSiMe 3 ). When the experiment was repeated, but with Me 3 SiCl in place of Me 2 SiHCl, it gives exclusively (Me 3 Si) 2 CHSi(C 6 H 4 Me- p )(Me)(OSiMe 3 ). Treatment of the organolithium reagent (Me 3 Si) 2 CLiSi(C 6 H 4 Me- p )(Me)(OSiMe 3 ) with Mel gives exclusively (Me 3 Si) 2 CMeSi(C 6 H 4 Me- p )(Me)(OSiMe 3 ). The related iodide (Me 3 Si) 3 CSi(C 6 H 4 Me- p )Mel reacts with ICI and IBr to give rearranged (Me 3 Si) 2 C(SiMe 2 X)Si(C 6 H 4 Me- p )Me 2 and unrearranged products (Me 3 Si) 3 CSi(C 6 H 4 Me- p )MeX, (X = Cl, Br) respectively. The rearranged bromide (Me 3 Si) 2 C(SiMe 2 Br)Si(C 6 H 4 Me- p )Me 2 reacts with a range of silver [I] salts AgY (Y = OOCCH 3 , SO 4 2 m ) and Mercury [II] salt HgY 2 (Y = OOCCH 3 , SO 4 2 m ) in glacial CH 3 COOH to give the corresponding species (Me 3 Si) 2 C(SiMe 2 OOCCH 3 )Si(C 6 H 4 Me- p )Me 2 . The reaction of the bromide with AgBF 4 in MeOH or i -PrOH give the corresponding rearranged products (Me 3 Si) 2 C(SiMe 2 Y)Si(C 6 H 4 Me- p )Me 2 (Y = --OMe, --OPr i ).     

H8Si8O12和H8Si7TiO12 团簇的几何构型和电子结构的从头算研究

应用HF、 MP2和杂化的B3LYP方法,使用3-21G基组,对H8Si8O12 和H8Si7TiO12团簇的几何构型、总能进行了计算,并在B3LYP/3-21G的水平上对硅原子的核磁共振化学位移进行了研究,得到的几何构型,以及核磁共振化学位移与实验结果进行了比较,发现吻合得很好。计算了H8Si8O12和H8Si7TiO12团簇的Mulliken布居数的大小。并对Si原子被Ti原子取代前后的H8Si8O12体系的几何构型、 Mulliken布居数的变化进行了比较和研究。     

The first alkene-platinum-silyl complexes: lifting the hydrosilation mechanism shroud with long-lived precatalytic intermediates and true pt catalysts

The synthesis, characterization, and exploratory chemistry of two classes of alkene-platinum-silyl complexes, which have been postulated as hydrosilation intermediates, are described in this report. The unique dimeric complexes 1, [R(3)Si(mu-Cl)(eta(2)-COD)Pt](2) [R(3)Si = Et(3)Si, MeCl(2)Si, Me(2)ClSi, "(EtO)(3)Si", PhMe(2)Si, and (Me(3)SiO)Me(2)Si; COD = cycloocta-1,5-diene], and the bis-silyl complexes 2, (eta(4)-COD)Pt(SiR(3))(2) (R(3)Si = Cl(3)Si, MeCl(2)Si, Me(2)ClSi, and PhMe(2)Si), are formed from the sequential reaction of 2 and 4 equiv of the corresponding hydrosilanes, respectively, with Pt(COD)Cl(2) in the presence of a small excess of COD. Complexes 1 are stable for many days in solution at room temperature but decompose via slow elimination of chlorosilane. Some of the bis-silyl compounds 2 are stable for extended periods under inert atmosphere and especially below 0 degrees C, either in the solid state or in solution (in the presence of a small excess of free COD). Complexes 2 display catalytic activity as discrete, molecular, and mononuclear species for hydrosilation and isomerization reactions. Compound 2c (R(3)Si = MeCl(2)Si) was fully characterized via multinuclear NMR spectroscopy and X-ray crystal structure analysis. The facile H-transfer rather than Si-transfer to bound COD provides experimental support for the sequence of insertive steps in the Chalk-Harrod catalytic cycle, at least for Pt-catalyzed hydrosilation.     

Linear and cyclic polysilanes containing the bis(trimethylsilyl)amino group: synthesis,reactions, and spectroscopic characterization

The reaction of linear (Si(n)Cl(2)(n)(+2); n = 3-5) and cyclic (Si(5)Cl(10)) perchloropolysilanes with 1 or 2 equiv of LiN(SiMe(3))(2) results in the formation of the bis(trimethylsilyl)amino derivatives (Me(3)Si)(2)NSi(3)Cl(7) (1), (Me(3)Si)(2)NSi(4)Cl(9) (2), (Me(3)Si)(2)N(SiCl(2))(n)N(SiMe(3))(2) (n = 3, 4; n = 4, 5; n = 5, 6), cyclo-(Me(3)Si)(2)NSi(5)Cl(9) (7), and cyclo-[(Me(3)Si)(2)N](2)Si(5)Cl(8) (8). 1-8 easily can be hydrogenated with LiAlH(4) to give the corresponding amino and diamino polysilanyl hydrides. The monosubstituted and cyclic compounds 1, 2, 7, and 8 additionally afford Si-Si bond scission products, which cannot be separated in all cases. Chloro- and dichloro derivatives of Si(3)H(8), n-Si(4)H(10), and n-Si(5)H(12) are obtained from the corresponding aminosilanes and dry HCl. All compounds were characterized by standard spectroscopic techniques. For Si-H derivatives the coupled (29)Si NMR spectra were analyzed to obtain an unequivocal structural proof.     

Singly and doubly lithium doped silicon clusters: geometrical and electronic structures and ionization energies

The geometric structures of neutral and cationic Si(n)Li(m)(0/+) clusters with n = 2-11 and m = 1, 2 are investigated using combined experimental and computational methods. The adiabatic ionization energy and vertical ionization energy (VIE) of Si(n)Li(m) clusters are determined using quantum chemical methods (B3LYP/6-311+G(d), G3B3, and CCSD(T)/aug-cc-pVxZ with x = D,T), whereas experimental values are derived from threshold photoionization experiments in the 4.68-6.24 eV range. Among the investigated cluster sizes, only Si(6)Li(2), Si(7)Li, Si(10)Li, and Si(11)Li have ionization thresholds below 6.24 eV and could be measured accurately. The ionization threshold and VIE obtained from the experimental photoionization efficiency curves agree well with the computed values. The growth mechanism of the lithium doped silicon clusters follows some simple rules: (1) neutral singly doped Si(n)Li clusters favor the Li atom addition on an edge or a face of the structure of the corresponding Si(n)(-) anion, while the cationic Si(n)Li(+) binds with one Si atom of the bare Si(n) cluster or adds on one of its edges, and (2) for doubly doped Si(n)Li(2)(0/+) clusters, the neutrals have the shape of the Si(n+1) counterparts with an additional Li atom added on an edge or a face of it, while the cations have both Li atoms added on edges or faces of the Si(n)(-) clusters.     

A Gaussian-3 theoretical study of small silicon-lithium clusters: electronic structures and electron affinities of SinLi(-) (n = 2-8)

The molecular structures of neutral Si n Li ( n = 2-8) species and their anions have been studied by means of the higher level of the Gaussian-3 (G3) techniques. The lowest energy structures of these clusters have been reported. The ground-state structures of neutral clusters are "attaching structures", in which the Li atom is bound to Si n clusters. The ground-state geometries of anions, however, are "substitutional structures", which is derived from Si n+1 by replacing a Si atom with a Li (-). The electron affinities of Si n Li and Si n have been presented. The theoretical electron affinities of Si n are in good agreement with the experiment data. The reliable electron affinities of Si n Li are predicted to be 1.87 eV for Si 2Li, 2.06 eV for Si 3Li, 2.01 eV for Si 4Li, 2.61 eV for Si 5Li, 2.36 eV for Si 6Li, 2.21 eV for Si 7Li, and 3.18 eV for Si 8Li. The dissociation energies of Li atom from the lowest energy structures of Si n Li and Si atom from Si n clusters have also been estimated respectively to examine relative stabilities.     

Oxidation pattern of small silicon oxide clusters: structures and stability of Si6On (n = 1-12)

We have performed systematic ab initio calculations to study the structures and stability of Si(6)O(n)() clusters (n = 1-12) in order to understand the oxidation process in silicon systems. Our calculation results show that oxidation pattern of the small silicon cluster, with continuous addition of O atoms, extends from one side to the entire Si cluster. Si atoms are found to be separated from the pure Si cluster one-by-one by insertion of oxygen into the Si-O bonds. From fragmentation energy analyses, it is found that the Si-rich clusters usually dissociate into a smaller pure Si clusters (Si(5), Si(4), Si(3), or Si(2)), plus oxide fragments such as SiO, Si(2)O(2), Si(3)O(3), Si(3)O(4), and Si(4)O(5). We have also studied the structures of the ionic Si(6)O(n)(+/-) (n = 1-12) clusters and found that most of ionic clusters have different lowest-energy structures in comparison with the neutral clusters. Our calculation results suggest that transformation Si(6)O(n)+(a) + O --> Si(6)O(n+1)+(a) should be easier.     

Si(CH3)3Cl分子电离电势和化学键能的测定

The photoionization spectroscopy of Si(CH3)3Cl in the range of 50 -130 nm was studied with synchrotron radiation source. The adiabatic ionization potentials of molecule Si(CH3)3Cl and radical Si(CH3)3 are 10.06 ±0.02 eV and 7.00±0.03 eV respectively. In addition, the appearance potentials of Si(CH3)2Cl+, Si(CH3)3+, SiCl+ and SiCH3+ were determined:
AP(Si(CH3)2Cl+) ＝10.49±0.02eV, AP(Si(CH3)3+) ＝ 11.91 ±0.02eV
AP(SiCl+) ＝ 18.64 ±0.06eV, AP(SiCH3+)＝ 18.62 ±0.02eV
From these, some chemical bond energies of Si(CH3)3Cl+ were calculated:
D(Si(CH3)2Cl+ - CH3) ＝0.43 ±0.02eV, D(Si(CH3)3+ - Cl) ＝ 1.85 ± 0.02eV
D(SiCH3+ - (2CH3 ＋ Cl)) ＝ 8.56 ± 0．06eV, D(SiCH3+ - 2CH3) ＝6.71±0．06eV
D(SiCl+ - 3CH3) ＝ 8.58 ± 0.06eV, D(SiCl＋- 2CH3) ＝ 8.15 ±0.06eV
D(SiCH3+- (CH3 ＋ Cl)) ＝8.13 ±0.06eV     

^29Si,^27AIMASNMR研究不同脱铝深度稀土 超稳Y沸石中Si、Al的分布

本文应用^29Si,^27AIMASNMR和XRD技术,测量了四种不同脱铝深度的稀土超稳Y沸石的骨架硅铝比,得到了一致的结果,并研究了稀土超稳Y沸石的脱铝过程和稀土离子和Y沸石骨架铝的机理.发现稀土离子存在时,Y沸石骨架中Si、Al的分布与相同硅铝比的ＨＹ不同,在浅、中度脱铝时,主要脱除的是Si(2Al)和Si(3Al)中的铝,深度脱铝时,主要是Si(1Al)和少量Si(2Al)中的铝,而Si(3Al)几乎不变,提出稀土离子最可能是位于方钠的Si(3Al)附近,平衡三个AlO 四面体上的负电荷,起到稳定Si(3Al)结构单元的作用.其次,稀土超稳Y沸石中总的非骨架铝(N~Al)~EF,随脱铝深度的增加而增加,仅只在REUSY-38的^27AIMAS NMR谱中观察到Al^3+非骨架铝的存在.^29Si,^27AIMASNMR     

Si(CH3)2Cl2分子的电离电势和化学键能的测定

有机硅化合物是半导体工业中产生硅元件的基本原料和有机合成中的重要试剂，是多年来大家研究较多的分子体系之一．本文报导了用同步辐射加速器产生的真空紫外光，电离St（CH3hCI。分子．在50－120n－m波长范围内，测量了各种离子产物与真空紫外光波长的关系，推算得它的绝热电离电势和离子中几个化学键的键能．1实验装置和方法本工作在国家同步辐射实验室光化学实验站进行．进行分子真空紫外光电离研究的实验系统已在文献山中详细描述．同步辐射加速器产生的真空紫外光波长用Ne气的电离势标定，其误差＜士0－Inln．单色仪的分辨率为河凸…     

Alkali metal complexes of sterically hindered mono- and di-carbanions containing Si-O bonds

The oxygen-bridged, silicon-substituted alkane {(Me3Si)2CH(SiMe2)}2O (1) may be prepared by the reaction of {(Me3Si)2CH}Li with ClSiMe2OSiMe2Cl in refluxing THF. Similarly, the alkane {(Me3Si)(Me2MeOSi)CH(SiMe2CH2)}2 (2) is readily accessible from the reaction between {(Me3Si)(Me2MeOSi)CH}Li and ClSiMe2CH2CH2SiMe2Cl under the same conditions. Compound 1 reacts with two equivalents of MeK to give the polymeric complex [[{(Me3Si)2C(SiMe2)}2O]K2(OEt2)]infinity [5(OEt2)] after recrystallisation. Treatment of 2 with two equivalents of either MeLi or MeK gives the corresponding complexes [{(Me3Si)(Me2MeOSi)C(SiMe2CH2)}2Li][Li(DME)3] [7(DME)3] and [{(Me3Si)(Me2MeOSi)C(SiMe2CH2)}2K2]n (8), respectively, after recrystallisation. Treatment of the alkane (Me3Si)2(Me2MeOSi)CH with one equivalent of MeK gives the polymeric complex [{(Me3Si)2(Me2MeOSi)C}K]infinity (3). These compounds have been identified by 1H and 13C{1H} NMR spectroscopy and elemental analyses and compounds 5(OEt2), 7(DME)3 and 3 have been further characterised by X-ray crystallography. Compound 7(DME)3 crystallises as a solvent-separated ion pair, whereas 5(OEt2) and 3 adopt polymeric structures in the solid state.     

Structural and optical properties of passivated silicon nanoclusters with different shapes: a theoretical investigation

Optimized geometries and electronic structures of hydrogenated silicon nanoclusters, which include the Td and Ih symmetries, have been generated by using the semiempirical AM1 and PM3 methods, the density functional theory (DFT) B3LYP method with the 6-31G(d) and LANL2DZ basis sets from the Gaussian 03 package, and the local density functional approximation (LDA), which is implemented in the SIESTA package. The calculated diameters for these Td symmetric hydrogenated silicon nanoclusters are in the range from 6.61 A (Si5H12) to 23.24 A (Si281H172). For the Ih symmetry, we calculated Si20H20 and Si100H60 nanoclusters only. Theoretically, the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is size dependent. The calculated energy gap decreases (Si5H12: 7.65 eV to Si281H172: 3.06 eV) while the diameter of silicon nanocluster increases. By comparing different calculated results, we concluded that the calculated energy gap by B3LYP/6-31G(d)//LDA/SIESTA is close to that from experiment and that the LDA/SIESTA result underestimates the experimental value. On the contrary, the AM1 and PM3 results overestimate the experimental results. For investigation of the optical properties of Si nanoclusters as a function of surface passivation, we carried out a B3LYP/6-31G(d)//LDA/SIESTA calculation of the Si35 and Si47 core clusters with full alkyl-, OH-, NH2-, CH2NH2-, OCH3-, SH-, C3H6SH-, and CN- passivations. The calculated optical properties of alkyl passivated Si35 nanoclusters (Si35(CH3)36, Si35(C2H5)36, and Si35(C3H7)36) are close to one another and are higher than those of oxide, nitride, and sulfide passivated Si 35 clusters. In conclusion, the alkyl passivant affects weakly the calculated optical gaps, and the electron-withdrawing passivants generate a red-shift in the energy gap of silicon nanoclusters. A size-dependent effect is also observed for these passivated Si nanoclusters.     

Fe68Si32合金液态结构与固态组织的相关性

利用液态X射线衍射仪研究了Fe68Si32合金的液态结构，获得了结构因子、径向分布函数、原子间的最近邻距离和配位数.结果表明，在1250～1450 ℃范围内液态合金的最近邻距离为0.259～0.260 nm，配位数为10.3(±0.2)；液态合金的结构因子在Q=15.5 nm－1处有一明显的预峰存在.根据预峰的特性，建立了Fe68Si32熔体的结构模型，即体心立方结构的有序Fe3Si原子团以共面的方式形成Fe3Si面心立方超结构(DO3)；合金在1250 ℃的径向分布函数的Gauss分解结果与合金的面心立方模型吻合较好.预峰的产生是面心立方超结构原子团中Si原子之间相互关联的外在表现. Fe68Si32合金的固态X射线衍射显示合金中含有Fe3Si相，而且其特征峰与合金的结构因子的峰位基本一致，表明Fe68Si32合金的液固态结构之间联系紧密.     

Partial halogenation of cyclic and branched perhydropentasilanes

The perhydropentasilanes (H(3)Si)(4)Si and Si(5)H(10) were chlorinated with SnCl(4) to give chlorohydropentasilanes without destruction of the Si-Si backbone. Tetrachloroneopentasilane (ClH(2)Si)(4)Si (2) was prepared in high yield from (H(3)Si)(4)Si and 3.5 equiv of SnCl(4), while Si(5)H(10) and an equimolar amount of SnCl(4) afforded a mixture of ～60% of ClSi(5)H(9) (1) with polychlorinated cyclopentasilanes and unreacted starting material, which could not be separated by distillation. The selective monochlorination of Si(5)H(10) was achieved starting from MesSi(5)Cl(9) (3; Mes = 2,4,6-trimethylphenyl) or TBDMP-Si(5)Cl(9) (4; TBDMP = 4-tert-butyl-2,6-dimethylphenyl). 3 or 4 was successfully hydrogenated with LiAlH(4) to give MesSi(5)H(9) (6) or TBDMP-Si(5)H(9) (7), which finally gave 1 along with aryl-H and Si(5)H(10) after treatment with an excess of liquid anhydrous HCl. All compounds were characterized by standard spectroscopic techniques. For Si-H derivatives, the coupled (29)Si NMR spectra were analyzed in detail to obtain an unequivocal structural assignment. The molecular structures of 2-4 were further confirmed by X-ray crystallography.     

Synthesis and characterization of iron silicon boron (Fe5Si2B) and iron boride (Fe3B) nanowires

Single-crystal iron silicon boron (Fe(5)Si(2)B) and iron boride (Fe(3)B) nanowires were synthesized by a chemical vapor deposition (CVD) method on either silicon dioxide (SiO(2)) on silicon (Si) or Si substrates without introducing any catalysts. FeI(2) and BI(3) were used as precursors. The typical size of the nanowires is about 5-50 nm in width and 1-20 mum in length. Different kinds of Fe-Si-B and Fe-B structures were synthesized by adjusting the ratio of FeI(2) vapor to BI(3) vapor. Single-crystal Fe(5)Si(2)B nanowires formed when the FeI(2) sublimator temperature was kept in the range of 540-570 degrees C. If the FeI(2) sublimator temperature was adjusted in the range of 430-470 degrees C, single-crystal Fe(3)B nanowires were produced. Fe(3)B nanowires grow from polycrystalline Fe(5)SiB(2) particles, while Fe(5)Si(2)B nanowires grow out of the Fe(5)Si(2)B layers, which are attached to triangle shaped FeSi particles. Both the ratio of FeI(2) vapor to BI(3) vapor and the formation of the particles (Fe(5)SiB(2) particles for the growth of Fe(3)B nanowires, FeSi particles for the growth of Fe(5)Si(2)B nanowires) are critical for the growth of Fe(3)B and Fe(5)Si(2)B nanowires. The correct FeI(2) vapor to BI(3) vapor ratio assures the desired phase form, while the particles provide preferential sites for adsorption and nucleation of Fe(3)B or Fe(5)Si(2)B molecules. Fe(3)B or Fe(5)Si(2)B nanowires grow due to the preferred growth direction of <110>.     

Tris(trichlorosilyl)tetrelide Anions and a Comparative Study of Their Donor Qualities

Trichlorosilylated tetrelides [(Cl₃Si)₃E]⁻ have been prepared by adding 1 equiv of a soluble Cl⁻ salt to (Cl₃Si)₄Si (E=Si) or 4 Si₂Cl₆/GeCl₄ (E=Ge). To assess their donor qualities, the anions [(Cl₃Si)₃E]⁻ (E=C, Si, Ge) have been treated with BCl₃, AlCl₃, and GaCl₃. Both BCl₃ and GaCl₃ give 1:1 adducts with the anionic centers. AlCl₃ leads to Cl⁻ abstraction from [(Cl₃Si)₃E]⁻ with formation of (Cl₃Si)₄E (E=Si or Ge). (Cl₃Si)₄Ge is cleanly converted to the perhydrogenated (H₃Si)₄Ge by use of Li[AlH₄]. Another case of Cl⁻ abstraction was observed for [(Cl₃Si)₃Ge ⋅ GaCl₃]⁻, which reacts with GaCl₃ to afford the neutral dimer [(Cl₃Si)₃Ge−GaCl₂]₂.     

Reactions of silicon atoms and small clusters with CO: experimental and theoretical characterization of SinCO (n=1-5), Si2(CO)2, c-Si2(mu-O)(mu-CSi), and c-Si2(mu-O)(mu-CCO) in solid argon

Reactions of silicon atoms and small clusters with carbon monoxide molecules in solid argon have been studied using matrix isolation infrared absorption spectroscopy. In addition to the previously reported SiCO monocarbonyl, Si(2)(CO)(2) and Si(n)CO (n=2-5) carbonyl molecules were formed spontaneously on annealing and were characterized on the basis of isotopic substitution and theoretical calculations. It was found that Si(2)CO, Si(3)CO, and Si(5)CO are bridge-bonded carbonyl compounds, whereas Si(4)CO is a terminal-bonded carbonyl molecule. The Si(2)(CO)(2) and Si(3)CO molecules photochemically rearranged to the more stable c-Si(2)(mu-O)(mu-CCO) and c-Si(2)(mu-O) (mu-CSi) isomers where Si(2) is inserted into the CO triple bond.