Interaction of Hg Atom with Bare Si（111） Surface

1INTRODUCTION In the past decades,mercury has been a very use-ful electrode material in the fabrication and electrical measurement of molecule modified metal-metal and metal-semiconductor junctions.Majda et al.[1,2]constructed a symmetric Hg-SCn-CnS-Hg junction to study the electron tunneling properties of alkanethio-late bilayers.Whitesides et al.[3～5]fabricated Hg-SAM/SAM-Metal(Ag,Au,Cu)junctions to investi-gate the electrical breakdown voltage of self-assem-bled monolayers(SAMs…     

Theoretical Studies of PCl3/H2 Gas Chromatography Mechanism

Density functional theory B3LYP method was firstly applied to fully optimize the geometrical configuration of each stable point on PCl3/H2 gas chromatography reaction potential energy surface on the 6-311G** basis set, and single point energy was computed at the QCISD(T)/ 6-311G** level, then the transition state was validated by analyzing the unique imaginary vibration modes of each transition state and calculating intrinsic reaction coordinate (IRC), and the major reaction and competing reaction paths of PCl3/H2 gas chromatography reaction were presented through comparing active energy barrier, and phosphor was finally gained from the reaction of PH and PCl.     

Reaction of 1,2-dibromobenzene with the Si(111)-7x7 surface, a DFT study

Reaction between 1,2-dibromobenzene and the Si(111)-7x7 surface has been studied theoretically on the DFT(B3LYP/6-31G(d)) level. A 12-atom silicon cluster, representing two adatoms and one rest atom of the faulted half of the unit cell, was used to model the silicon surface. The first step of the reaction was a covalent attachment (chemisorption) of an intact 1,2-dibromobenzene molecule to the silicon cluster. Binding energies were calculated to be between 1.04 and 1.14 eV, depending on the orientation of the molecule. A second step of the reaction was the transfer of the Br atom to the silicon cluster. Activation energies for the transfer of the Br atom were calculated to be between 0.4 and 0.6 eV, suggesting that the thermal bromination reaction occurs on a microsecond time scale at room temperature. A third step of the reaction could be the transfer of the second Br atom of the molecule, the desorption of the organic radical, or the change of the adsorption configuration of the radical, depending on the original orientation of the adsorbed intact molecule. A novel, aromatic, two-sigma-bound adsorbed configuration of the C6H4 radical, in which a carbon ring of the radical is perpendicular to the silicon surface, has been introduced to explain previous experimental observations (Surf. Sci. 2004, 561, 11).     

Density Functional Investigation of Methanethiol and Dimethyl Sulfide Adsorption on Zeolite

The density functional theory and cluster model methods have been employed to investigate the interactions between methanethiol, dimethyl sulfide and zeolites. The molecular complexes formed by adsorption of methanethiol or dimethyl sulfide on silanol H3SiOSi(OH)2OSiH3 with five coordination forms or four coordination forms, and complexes formed by interactions of Bronsted acid sites of bridging hydroxyl H3Si(OH)Al(OH)2OSiH3 with methanethiol or dimethyl sulfide have been investigated. Full optimization and frequency analysis of all cluster models have been carried out using the B3LYP hybrid method at 6-31 G (d,p) basis set level for hydrogen, silicon, aluminum, oxygen, carbon, and sulfur atoms. The structures and energy changes of different coordination forms between methanethiol and H3Si(OH)Al(OH)2OSiH3, dimethyl sulfide and H3Si(OH)Al(OH)2OSiH3, methanethiol and H3SiOSi(OH)2OSiH3, dimethyl sulfide and H3SiOSi(OH)2OSiH3 complexes have been comparatively studied. The calculated results showed the nature of interactions that led to the formation of all complexes was van der Waals force confirmed by an insignificant change of geometric structures and properties. The conclusions that methanethiol and dimethyl sulfide molecules were adsorbed on bridging hydroxyl group prior to silanol group were obtained on the basis of adsorption heat, the most stable adsorption models of a 6 ring structure for interaction between bridging hydroxyl and methanethiol, and a 7 ring structure for interaction between bridging hydroxyl and dimethyl sulfide.     

Theoretical Study of Ethanethiol Adsorption on HZSM-5 Zeolite

The density functional theory and the cluster model methods have been employed to investigate the interactions between ethanethiol and HZSM-5 zeolites. Molecular complexes formed by the adsorption of ethanethiol on silanol H3SiOH with two coordination forms, model Bronsted acid sites of zeolite cluster H3Si(OH)Al(OH)2SiH3 interaction with ethanethiol, aluminum species adsorbed ethanethiol have been comparatively studied. Full optimization and frequency analysis of all cluster models have been carried out using B3LYP hybrid method at 3-21G basis level for hydrogen atoms and 6-31G(d) basis set level for silicon, aluminum, oxygen, carbon, and sulfur atoms. The structures and energy changes of different coordination forms of H3Si(OH)Al(OH)2SiH3-ethanethiol, silanol-ethanethiol and Al(OH)3-ethanethiol have been studied. The calculated results showed the nature of interactions was van der Waals force as exhibited by not much change in geometric structures and properties. The preference order of ethanethiol adsorbed on HZSM-5 zeolite may be residual aluminum species, bridging hydroxyl groups and silanol OH groups from the adsorption heat. The adsorbed models of protonized ethanethiol on bridging hydroxyl OH groups and linear hydrogen bonded ethanethiol on bridging OH groups suggested in literature might not exist as revealed by this theoretical calculation. Possible adsorption models were obtained for the first time.     

Synthesis,Properties, Structure and Reactivity of Sodium 2,3,4,5-Tetra- tert -butylcyclopentaphosphanide

The reaction between Na, t BuPCl 2 , and PCl 3 in thf gives Na[ cyclo -( t Bu 4 P 5 )] ( 1 ). 1 reacts with PCl 3 to yield ( cyclo - t Bu 3 P 4 ) t BuPCl ( 2 ), and with a proton source, such as HCl, NH 4 Cl, or t BuCl, to give cyclo - t Bu 4 P 5 H ( 3 ). The reaction of 1 with [MCl 2 (PRR' 2 ) 2 ] (M = Ni; R = R' = Et; M = Pd, Pt, R = Ph, R' = Me) gives [Ni{ cyclo -( t Bu 3 P 5 )}(PEt 3 ) 2 ] ( 4 ), [Pd{ cyclo -( t Bu 4 P 5 )} 2 ] ( 5 ), and [PtCl{ cyclo -( t Bu 3 P 4 ) t BuP}(PPhMe 2 )] ( 6 ). 1-6 were characterized by 31 P{ 1 H} NMR spectroscopy, and 1 and 4-6 were also characterized by X-ray crystallography.     

Sterically encumbered acyclic diphosphazanes: synthesis, conformations and coordination behavior

The reaction between lambda3-diphosphazane [EtN(PCl2)2] and the sodium salts of substituted phenols affords sterically encumbered diphosphazanes [EtN{P(OR)2}2] (R = -C6H3iPr2-2,6 (1), -C6H3Me2-2,6 (2) and -C6H2Me3-2,4,6 (3)). When the same reaction was carried out with bulky sodium 2,4-di-tert-butyl-4-methylphenoxide, only a monosubstitution takes place to result in the formation of [EtN{PCl(OR)}2] (R = -C6H2tBu2-2,6-Me-4) (4). Further reaction of 2 with [Mo(CO)4(NBD)] produces cis-[(EtN{P(OC6H3Me2-2,6)2}2)Mo(CO)4] (5). Diphosphazanes 1-4 and the metal derivative 5 have been characterized by means of their analytical data and EI-MS, IR and multinuclear NMR (1H and 31P) spectral data. The solid-state structure of the diphosphazanes 1, 2 and 4, and the molybdenum complex 5 have been determined by X-ray diffraction studies. Irrespective of the size of substituent, the bulky groups on the phosphorus and nitrogen are on the same side of the P-N-P skeleton with a local C2v symmetry. The central nitrogen remains almost trigonal planar in all the compounds.     

The Pd(4)(dppm)(4)(H)(2)(2+) cluster: a precatalyst for the homogeneous hydrogenation of alkynes

The catalytic properties of the title cluster toward the homogeneous hydrogenation of phenylacetylene, diphenylethyne and phenyl-1-propyne have been investigated as a function of temperature, pressure, solvents, substrate and cluster concentrations, and counterions. The title cluster is a precatalyst that exhibits a good catalytic activity under mild conditions (1 atm of H(2) at 20 degrees C) for the hydrogenation of alkynes and alkenes. For the alkyne substrates, the turnover frequencies (tof's) range between 200 and 500 h(-)(1), and the product distribution varies as: cis-products, 75-90%; trans-products; 0-8% after 3 h of reaction. Based on the graphs -d[substrate]/dt vs [Pd(4)](1/2), the mechanism indicates a cluster dissociation into two dimers (presumably of the type Pd(2)(dppm)(2)(H)(solvent)(+)). The variations of tof (or -d[substrate]/dt) as a function of [substrate] and pressure of H(2) are linear. At 1600 psi of H(2), the tof can reach 2500-3000 h(-)(1) (in THF). The tof also increases with temperature reaching a maximum at approximately 35 degrees C (tof: 1000-1300 h(-)(1)), but at higher temperatures cluster decomposition begins to occur, leading to a rapid decrease in rates of catalysis. At 50 degrees C, no catalysis is observed. The hydrogenation reaction can be stopped at the corresponding cis-alkenes with approximately 95% yields, depending on the substrate and experimental conditions used. The tof's also vary with the solvent, where stronger coordinating solvent molecules give higher tof's. In addition, the tof's do not change with the nature of the counterion, which acts as "spectator" in the catalysis.     

Phosphacarborane chemistry: the 7,8,9,11-, 7,9,8,10- and 7,8,9,10-isomers of nido-P2C2B7H9--diphosphadicarbaborane analogues of 7,8,9,10-C4B7H11

The reaction between the carborane arachno-4,6-C2B7H13 (1) and PCl3 in dichloromethane in the presence of a "proton sponge" (PS = 1,8-dimethylaminonaphthalene) resulted in the isolation of the eleven-vertex nido-diphosphadicarbaboranes 7,8,9,11-P2C2B7H, (2) and 3-Cl-7,8,11-P2C2B7H, (3-Cl-2) in yields of 54 and 7%, respectively. Replacement of the PS by NEt3 in the same reaction gave diphosphadicarbaboranes 2 and 3-CI-2 together with the isomeric species nido-7,9,8,10-P2C2B7H, (3) in yields of 28, 15 and 3%, respectively. The reaction between the isomeric carborane arachno-4,5-C2B7H13 (4) and PCl3 in dichloromethane in the presence of PS gave the asymmetrical isomer, nido-7,8,9,10-P2C2B7H, (5). along with the chloro derivatives 4-Cl-7,8,9,10-P2C2B7H8 (4-Cl-5) and 11-Cl-7,8,9,10-PC2B7,H8 (11-Cl-5) (yields of 21, 1 and 13%, respectively). The structures of the chlorinated derivatives 3-Cl2 and 11 -Cl-5 were determined by X-ray diffraction analysis. In addition, the structures of all compounds isolated were geometry-optimised and confirmed by comparison of experimental 11B chemical shifts with those calculated by the GIAO-SCF/II//RMP2(fc)/6-31G* method. The calculations also include the structure and 11B NMR shifts of the isomer nido-7,10,8,9-P2C2B7H9 (6) which has not yet been isolated.     

Synthesis and reactivity of perhalogenated acyclic and metallacyclic tantalum(V) phosphoraniminato complexes: discovery of an unexpected ligand coupling reaction to form the novel phosphazenium salt

The reaction of TaCl5 with a single equivalent of Cl3P=NSiMe3 resulted in the isolation of the perhalogenated (phosphoraniminato) tantalum(V) complex TaCl4(N=PCl3) (1). Reaction of 1 with an excess of THF and subsequent cooling produced crystals of TaCl4(N=PCl3)(THF) (1.THF), which possesses a distorted octahedral Ta center with a THF molecule coordinated trans to the phosphoraniminato ligand. The reaction of 1 with the aminophosphoranimine, (Me3Si)2NPCl2=NSiMe3, resulted in a [3 + 1] cyclocondensation reaction to form the metallacyclic complex, TaCl3(N=PCl3)[N(SiMe3)PCl2N(SiMe3)] (2), which contains a TaNPN four-membered ring and a phosphoraniminato ligand (N=PCl3). The analogous [3 + 1] cyclocondensation reaction between (Me3Si)2NPCl2=NSiMe3 and TaCl5 led to the isolation of TaCl4[N(SiMe3)PCl2N(SiMe3)] (3). An attempt to cleave the NPN ligand from the Ta center in 2 via protonolysis with HCl led to an unusual phosphoraniminato ligand coupling reaction to yield the novel phosphazenium salt [N(PCl2NH2)2][TaCl6] (4). All new compounds (1.THF and complexes 1-4) were characterized by single-crystal X-ray diffraction.     

Interaction of PH3 with acetaldehyde in aqueous media and chemistry of [HO(Me)CH]4PCl

The known phosphonium chloride [HO(Me)CH]₄PCl was prepared at ambient conditions from PH₃ and acetaldehyde in aqueous HCl, and characterized by elemental analysis and ¹H and ³¹{¹H} NMR spectroscopy. Attempts to obtain the tertiary phosphine [HO(Me)CH]₃P via reaction of [HO(Me)CH]₄PCl with Na₂SO₃ or Et₃N in aqueous media under Ar revealed that [HO(Me)CH]₃P is unstable and equilibrates with the secondary phosphine [HO(Me)CH]₂PH and acetaldehyde. A 1:4 reaction of [HO(Me)CH]₄PCl with NaHSO₃ at room temperature under Ar affords first the oxide [HO(Me)CH]₂P(O)H and then the phosphinic acid [HO(Me)CH]₂P(O)OH. A 1:1 reaction of [HO(Me)CH]₄PCl with Na₂S₂O₃ affords the sulfide [HO(Me)CH]₃PS. ³¹{¹H} and ¹H NMR data for all the (α-hydroxyethyl)phosphorus species are reported for the first time.     

Vapor-phase synthesis of mesoporous SiO2-P2O5 thin films

Mesoporous SiO2-P2O5 films were synthesized from the vapor phase onto a silicon substrate. First, a precursor solution of cetyltrimethylammonium bromide (C16TAB), H3PO4, ethanol, and water was deposited on a silicon substrate by a spin-coating method. Then, the C16TAB-H3PO4 composite film was treated with tetraethoxysilane (TEOS) vapor at 90-180 degrees C for 2.5 h. The H3PO4-C16TAB composite formed a hexagonal structure on the silicon substrate before vapor treatment. The TEOS molecules penetrated into the film without a phase transition. The periodic mesostructure of the SiO2-P2O5 films was retained after calcination. The calcined films showed a high proton conductivity of about 0.55 S/cm at room temperature. The molar ratio of P/Si in the SiO2-P2O5 film was as high as 0.43, a level that was not attained by a premixing sol-gel method. The high phosphate group content and the ordered periodic mesostructure contributed to the high proton conductivity.     

The Reaction of Triphenylmethyl-substituted Primary and Secondary Phosphines with Phosgene

The nature of the products from the reaction of TrtPH₂ ( 1 ) with an equimolar amount of phosgene strongly depends on the solvent. The initial intermediate 2 was isolated from toluene, but lost CO in dichloromethane, and HCl in diethyl ether, yielding TrtP(H)Cl ( 3 ), and (TrtPCO)₂ ( 4 b ), respectively. TrtP(H)Cl ( 3 ) was found to be a halophosphine of amazing stability. Treatment of 3 with excess phosgene led to partial substitution of the P-bonded proton for C(:O)Cl with formation of 5 , which did not eliminate CO to give TrtPCl₂. Substitution of chlorine in TrtP(H)Cl ( 3 ) for fluorine or bromine furnished the halophosphines, 6 and 7 . Minute quantities of the diphosphene 8 were formed upon treatment of 3 with NEt₃ or DBU. The course of the reaction between the secondary phosphines Trt(R)PH and phosgene depends on the group R. If R was t-Bu, formation of a mixture of Trt(t-Bu)PCl ( 10 ), and t-BuPCl₂ (resulting from partial cleavage of the P–C-bond) was observed. Although in the case of R = Ph, the intermediate 12 could be isolated, at elevated temperature HCl was eliminated from 12 , giving Trt(Ph)PCl ( 13 ). The diphosphine (TrtPH)₂ ( 14 ) is inert towards HCl-free phosgene. In the presence of HCl the P–P-bond in 14 was cleaved, and upon chlorination of the resulting TrtPH₂ ( 1 ) by phosgene, TrtP(H)Cl ( 3 ) was obtained as the only phosphorus-containing product.     

Density functional theory study of the adsorption of formaldehyde on Pd4 and on Pd4/gamma-Al2O3 clusters

B3LYP/LANL2DZ and B3LYP/6-31G(d)-restricted and -unrestricted calculations are employed to calculate energies and adsorption forms of formaldehyde adsorbed on planar and on tetrahedral Pd4 clusters and on a Pd4 cluster supported on Al10O15. Formaldehyde adsorbs on planar Pd4 in the eta(2)(C,O)-di-sigma adsorption mode, while on tetrahedral Pd4, it adsorbs in the eta(2)(C,O)-pi adsorption mode. The adsorption energy on planar Pd4 is -21.4 kcal x mol(-1), whereas for the tetrahedral Pd4 cluster, the adsorption energy is -13.2 kcal x mol(-1). The latter value is close to experimental findings (-12 to -14 kcal x mol(-1)). Adsorption of formaldehyde on Pd4 supported on an Al10O15 cluster leads essentially to the same result as that found for adsorption on the tetrahedral Pd4 cluster. Charge density analysis for the interaction between formaldehyde and the Pd4 clusters indicates strong backdonation in the eta(2) adsorption mode, leading to positive charge on the Pd4 cluster. NBO analysis shows that the highly coordinated octahedral aluminum atoms of Al10O15 donate electron density to the supported Pd4 cluster, while tetrahedral aluminum atoms with lower coordination number have acidic nature and therefore act as electron acceptors.     

Phosphorus complexes of N-fused porphyrin and its reduced derivatives: new isomers of porphyrin stabilized via coordination

N-fused isophlorin 3 and its tautomeric phlorin forms 4 and 5, the new constitutional isomers of porphyrin which preserve the basic skeleton of their maternal N-fused porphyrin, have been identified in the course of investigation of phosphorus insertion into N-fused porphyrin 2. N-fused porphyrin reacts with PCl3 in toluene yielding phosphorus(V) N-fused isophlorin 3-P wherein the macrocycle acts as a trianionic tridentate ligand. The identical product has been formed in the reaction of N-confused porphyrin 1 and POCl3 or PCl3. The coordinating environment of phosphorus(V) in 3-P as determined by X-ray crystallography resembles a distorted trigonal pyramid with the nitrogen atoms occupying equatorial positions with the oxygen atom lying at the unique apex. Phosphorus(V) is significantly displaced by 0.732(1) A from the N3 plane. The P-N distances are as follows P-N(22) 1.664(2), P-N(23) 1.645(2), and P-N(24) 1.672(2). All P-N(pyrrolic) bond lengths are markedly shorter than the P-N distances in phosphorus porphyrins. 3-P is susceptible to proton addition at the inner C(9) carbon atom, yielding aromatic 4-P. The modified macrocycle acts as a dianionic ligand and allows the efficient 18 pi-electron delocalization pathway. Two stereoisomers affording the syn (4-P syn) and anti (4-P anti) location of the H(9) atom with respect to the oxygen atom of the PO unit have been identified by (1)H NMR. A regioselective reduction of free base N-fused porphyrin 2 with NaBH4 yielded a nonaromatic isomer of 4, that is, N-fused phlorin 5 due to an addition of a hydride to the C(15) carbon and a proton to one of the pyrrolic nitrogens. The isomer 5 reacts with PCl 3 yielding phosphorus(V) fused isophlorin 3-P. Density functional theory has been applied to model the molecular and electronic structure of porphyrin isomers 3, 4, and 5 and their phosphorus(V) complexes.     

Reaction of m-terphenyldichlorophosphanes with sodium azide: synthesis and characterization of stable azidocyclophosphazenes

Reaction of the m-terphenyldichlorophosphanes 2,6-(2-MeC(6)H(4))(2)C(6)H(3)PCl(2) (1), 2,6-(4-t-BuC(6)H(4))(2)C(6)H(3)PCl(2) (2), or 2,6-Mes(2)C(6)H(3)PCl(2) (3) with excess NaN(3) in acetonitrile at room temperature afforded the corresponding bisazidophosphanes 2,6-(2-MeC(6)H(4))(2)C(6)H(3)P(N(3))(2), 2,6-(4-t-BuC(6)H(4))(2)C(6)H(3)P(N(3))(2) (5), or 2,6-Mes(2)C(6)H(3)P(N(3))(2) (6) (Mes = 2,4,6-Me(3)C(6)H(2)), respectively. These compounds are thermally labile and decompose into a number of azidophosphazenes. The azidocyclophosphazenes [NP(N(3))(C(6)H(3)(4-t-BuC(6)H(4))(2)-2,6)](3) (4) and [NP(N(3))C(6)H(3)Mes(2)-2,6](2) (8) have been isolated from these mixtures. All compounds were characterized by (1)H, (13)C, (31)P NMR and IR spectroscopy. Crystal structures of 2, 4, and 8 were determined.     

沸石桥羟基和硅羟基与噻吩相互作用的理论研究

采用密度泛函理论和模型簇法研究了噻吩和沸石分子筛桥羟基和硅羟基的相互作用.对噻吩吸附在硅羟基H3SiOH可能的两种配位方式及吸附在沸石模型簇H3Si(OH)Al(OH)2OSiH3桥羟基B酸上可能的两种配位方式进行了比较分析.所有模型簇采用B3LYP混合方法对氢原子在6-31G基组水平上,对硅原子、铝原子、氧原子、碳原子、硫原子在6-31 G(d)基组水平上进行了全优化和频率分析.着重考察了噻吩与硅羟基及分子筛桥羟基模型簇不同配位方式所形成的配合物的结构及能量变化.计算结果表明由于在形成沸石-噻吩和硅羟基-噻吩配合物的结构和性质变化不明显,所以它们之间的相互作用为范德华作用力.从噻吩在沸石分子筛的桥羟基和硅羟基与噻吩的相互作用的吸附热可以推断,噻吩优先吸附在桥羟基上,只有桥羟基吸附饱和后方吸附在硅羟基上.由频率分析结果和实验结果的一致性可以证明所推测吸附模型的正确性.     

单晶硅上化学气相沉积铜薄膜的机理研究

A versatile metal-organic chemical vapor deposition (MOCVD) system was designed and constructed. Copper films were deposited on silicon (100) substrates by chemical vapor deposition (CVD) using Cu(hfac)2 as a precursor. The growth of Cu nucleus on silicon substrates by H2 reduction of Cu(hfac)2 was studied by atomic force microscopy and scanning electron microscopy. The growth mode of Cu nucleus is initially Volmer-Weber mode (island), and then transforms to Stranski-Rastanov mode (layer-by-layer plus island).The mechanism of Cu nucleation on silicon (100) substrates was further investigated by X-ray photoelectron spectroscopy. From Cu2p, O1s, F1s, Si2p patterns, the observed C=O, OH and CF3/CF2 should belong to Cu(hfac) formed by the thermal dissociation of Cu(hfac)2. H2 reacts with hfac on the surface, producing OH. With its accumulation, OH reacts with hfac, forming HO-hfac, and desorbs, meanwhile, the copper oxide is reduced, and thus the redox reaction between Cu(hafc)2 and H2 occurs.     

Reversible skeletal transmetalations of inorganic rings: isolation of aluminatophosphazenes, a zwitterionic phosphazene, and a donor-stabilized alumazine-phosphazene hybrid cation

Synthesis of the cyclic aluminatophosphazene ring N(PCl2NMe)2AlMeCl (5) has been achieved via a skeletal transmetalation reaction between AlMe3 and the boratophosphazene N(PCl2NMe)2BCl2 (1). Reaction of 5 with various halogenated Lewis acids such as GaCl3 yielded the fully chlorinated aluminum heterocycle N(PCl2NMe)2AlCl2 (8) through a methyl-halogen exchange process. In contrast, treatment of 5 with excess AlMe3 resulted in complete methylation at aluminum to give N(PCl2NMe)2AlMe2 (6). Compound 5 was reacted with various Ag+ salts with weakly coordinating anions, including Ag[OSO2CF3], which afforded the triflate-substituted heterocycle N(PCl2NMe)2AlMe(OSO2CF3) (9). The reaction of 5 with Ag[BF4] surprisingly produced the previously known fluorinated boratophosphazene N(PCl2NMe)2BF2 (10). The transformation of 1 to 5 and then to 10 represents a rare, formally reversible, skeletal transmetalation process involving boron and aluminum. Treatment of 5 with Ag[PF6] led to the insertion of phosphorus in place of aluminum to form the novel zwitterionic fluorinated phosphorus(V) heterocycle N(PCl2NMe)2PF4 (11). The ethyl-substituted aluminatophosphazene N(PCl2NMe)2AlMeEt (14) reacted cleanly with a 1:1 mixture of [Ph3C][B(C6F5)4] and THF to give the novel donor-stabilized alumazine-phosphazene hybrid cation, [7.THF]+, as the [B(C6F5)4]- salt [N(PCl2NMe)2AlMe.THF][B(C6F5)4] (15).     

系统研究溶剂和温度对形成三种钴簇基金属-有机框架化合物的影响：结构和气体吸附性质

通过调控DMSO/DMF/H2O混合溶剂中溶剂成分的物质的量比和反应温度,合成出3种基于1,3,5-三(4′-羧甲基苯基)苯(H3BTB)和氯化钴的钴簇基金属-有机框架化合物(NH2Me2)2[Co3O(BTB)2(H2O)].2H2O.4.5DMF.7.5DMSO(1),(NH2Me2)2[Co4O(BTB)8/3].6H2O.13DMSO(2)和(NH2Me2)2[Co6O3(BTB)8/3(H2O)4].5H2O.5DMF.13DMSO(3),它们分别含有三核Co3O簇、四核Co4O簇和六核Co6O3簇。这种六核簇为我们首次发现。研究表明,相对中等的温度105℃和较多DMF的使用有利于三核簇的形成;125℃高温和溶剂DMSO有利于四核簇的构建;与形成1的条件相比,较低的温度95℃和更多水的存在则有利于六核簇的生成。2和3虽然由不同的金属簇构成,但具有相同的框架结构,Schlfli符号为(43)8(48.64.812.104)3。此外,还研究了2和3抽出溶剂后产物的气体吸附性质,它们均具有较高的氢气吸附焓。