Highly luminescent complexes [Mo6X8(n-C3F7COO)6]2- (X=Br, I)

New complexes (Bu(4)N)(2)[Mo(6)X(8)(n-C(3)F(7)COO)(6)] (X = Br, I) display extraordinarily bright long-lived red phosphorescence both in solution and solid phases, with the highest emission quantum yields and the longest emission lifetimes among hexanuclear metal cluster complexes of Mo, W and Re, hitherto reported.     

Simple estimation of electron correlation energy for multi-atomic strong ionic compounds KX and (KX)2 (X = OH, NC)

On the basis of the calculations and analyses of the intrapair and interpair correlation energy of KX (X = OH, NC) molecules and the results of the transferability of both the innermost intrapair correlation energy and the inner core effect of K and X in KX molecules, we defined and calculated the Kδ- and Xδ-correlation contributions to the total correlation energy of KX molecules. With the comparison of the pair correlation energy of K+, X- and KX systems, we present a simple estimation method to estimate the electron correlation energy of strong ionic compound by summarizing the correlation energy of its constituent ion and ionic group. By using this simple method, the reasonable estimation results of the correlation energy of (KOH)2 and (KNC)2 have been obtained at mp2/6-311++G(d) level with Gaussian98 program, and the deviations are very small. Applying the scheme of "Separate Large System into Smaller Ones" to the calculation of electron correlation energy of large ionic compounds, it can not only     

Potential surfaces and dynamics of the O(3P)+H2O(X1A1)-->OH(X2pi)+OH(X2pi) reaction

We present global potential energy surfaces for the three lowest triplet states in O(3P)+H2O(X1A1) collisions and present results of classical dynamics calculations on the O(3P)+H2O(X1A1)-->OH(X2pi)+OH(X2pi) reaction using these surfaces. The surfaces are spline-based fits of approximately 20,000 fixed geometry ab initio calculations at the complete-active-space self-consistent field+second-order perturbation theory (CASSCF+MP2) level with a O(4s3p2d1f)/H(3s2p) one electron basis set. Computed rate constants compare well to measurements in the 1000-2500 K range using these surfaces. We also compute the total, rovibrationally resolved, and differential angular cross sections at fixed collision velocities from near threshold at approximately 4 km s(-1) (16.9 kcal mol(-1) collision energy) to 11 km s(-1) (122.5 kcal mol(-1) collision energy), and we compare these computed cross sections to available space-based and laboratory data. A major finding of the present work is that above approximately 40 kcal mol(-1) collision energy rovibrationally excited OH(X2pi) products are a significant and perhaps dominant contributor to the observed 1-5 micro spectral emission from O(3P)+H2O(X1A1) collisions. Another important result is that OH(X2pi) products are formed in two distinct rovibrational distributions. The "active" OH products are formed with the reagent O atom, and their rovibrational distributions are extremely hot. The remaining "spectator" OH is relatively rovibrationally cold. For the active OH, rotational energy is dominant at all collision velocities, but the opposite holds for the spectator OH. Summed over both OH products, below approximately 50 kcal mol(-1) collision energy, vibration dominates the OH internal energy, and above approximately 50 kcal mol(-1) rotation is greater than vibrational energy. As the collision energy increases, energy is diverted from vibration to mostly translational energy. We note that the present fitted surfaces can also be used to investigate direct collisional excitation of H2O(X1A1) by O(3P) and also OH(X2pi)+OH(X2pi) collisions.     

簇合物Mo_2X_8~(4-)(X=Cl,Br)低能态电子光谱

应用间略微分重叠自洽场和组态作用(INDO/S-CI)方法,计算双核簇合物Mo_2X_8~(4-)(X=Cl,Br)基态~1A_(1g)至不同低能态的d电子自旋允许的跃迁能,得出Mo—Mo四重键均裂时所需的能量大小依次为键σ>π>>δ。对于Mo_2Cl_8~(4-)簇合物态~1A_(1g)→1~1A_(2u)(δ→δ~*)和~1A_(1g)→2~1E_g(π→δ~*)的电子跃迁能,理论值(15584和22587cm~(-1))与低温时测得光谱实验值(18083和22000cm~(-1))较为接近。此外,本文还提出了簇合物Mo_2X_8~(4-)的态相同而X不同时,电子跃迁能变化,主要决定于参与电子转移过程的分子轨道组成成份的看法。     

Simple estimation of electron correlation energy for multi-atomic strong ionic compounds KX and (KX)2 (X=OH, NC)

On the basis of the calculations and analyses of the intrapair and interpair correlation energy of KX (X = OH, NC) molecules and the results of the transferability of both the innermost intrapair correlation energy and the inner core effect of K and X in KX molecules, we defined and calculated the K^δ+ and X^δ-correlation contributions to the total correlation energy of KX molecules. With the comparison of the pair correlation energy of K⁺, X^- and KX systems, we present a simple estimation method to estimate the electron correlation energy of strong ionic compound by summarizing the correlation energy of its constituent ion and ionic group. By using this simple method, the reasonable estimation results of the correlation energy of (KOH)₂ and (KNC)₂ have been obtained at mp2/6-311++G(d) level with Gaussian98 program, and the deviations are very small. Applying the scheme of “Separate Large System into Smaller Ones” to the calculation of electron correlation energy of large ionic compounds, it can not only save lot of computation work but also reach the chemical accuracy.     

Synthesis and P-P cleavage reactions of [P(X)X']2; X-ray structures of [Co[P(X)X'](CO)3] and P4[P(X)X']2[X = N(SiMe3)2, X'= NPri2

Treatment of P(X)(X')Cl with KC8 gave the crystalline diphosphine [P(X)X']2 (1) which dissociated reversibly into the phosphinyl radical *P(X)X' (2), a plausible intermediate in the reaction of with [Cr(CO)6], [Co(NO)(CO)3] or P4, yielding [Cr[P(X)X']2(CO)3] (3), [Co[P(X)X'](CO)3] (4), or 1,4-P4[P(X)X']2 (5); the P(X)X' substituent is pyramidal at P in but planar in [X = N(SiMe3)2, X'= NPri2].     

New synthetic routes to biscarbonylbipyridinerhenium(I) complexes cis,trans-[Re(X2bpy)(CO)2(PR3)(Y)n+ (X2bpy = 4,4'-X2-2,2'-bipyridine) via photochemical ligand substitution reactions, and their photophysical and electrochemical properties

Photochemical ligand substitution of fac-[Re(X2bpy)(CO)3(PR3)]+ (X2bpy = 4,4'-X2-2,2'-bipyridine; X = Me, H, CF3; R = OEt, Ph) with acetonitrile quantitatively gave a new class of biscarbonyl complexes, cis,trans[Re(X2bpy)(CO)2(PR3)(MeCN)]+, coordinated with four different kinds of ligands. Similarly, other biscarbonylrhenium complexes, cis,trans-[Re(X2bpy)(CO)2(PR3)(Y)]n+ (n = 0, Y = Cl-; n = 1, Y = pyridine, PR'3), were synthesized in good yields via photochemical ligand substitution reactions. The structure of cis,trans-[Re(Me2bpy)(CO)2[P(OEt)3](PPh3)](PF6) was determined by X-ray analysis. Crystal data: C38H42N2O5F6P3Re, monoclinic, P2(1/a), a = 11.592(1) A, b = 30.953(4) A, c = 11.799(2) A, V = 4221.6(1) A3, Z = 4, 7813 reflections, R = 0.066. The biscarbonyl complexes with two phosphorus ligands were strongly emissive from their 3MLCT state with lifetimes of 20-640 ns in fluid solutions at room temperature. Only weak or no emission was observed in the cases Y = Cl-, MeCN, and pyridine. Electrochemical reduction of the biscarbonyl complexes with Y = Cl- and pyridine in MeCN resulted in efficient ligand substitution to give the solvento complexes cis,trans-[Re(X2bpy)(CO)2(PR3)(MeCN)]+.     

Microhydration of X2 gas (X = Cl, Br, and I): a theoretical study on X2.nH2O clusters (n = 1-8)

Structure and properties of hydrated clusters of halogen gas, X2.nH2O (X = Cl, Br, and I; n = 1-8) are presented following first principle based electronic structure theory, namely, BHHLYP density functional and second-order Moller-Plesset perturbation (MP2) methods. Several geometrical arrangements are considered as initial guess structures to look for the minimum energy equilibrium structures by applying the 6-311++G(d,p) set of the basis function. Results on X2-water clusters (X = Br and I) suggest that X2 exists as a charge separated ion pair, X+delta-X-delta in the hydrated clusters, X2.nH2O (n > or = 2). Though the optimized structures of Cl2.nH2O clusters look like X2.nH2O (X = Br and I) clusters, Cl2 does not exist as a charge separated ion pair in the presence of solvent water molecules. The calculated interaction energy between X2 and solvent water cluster increases from Cl2.nH2O to I2.nH2O clusters, suggesting solubility of gas-phase I2 in water to be a maximum among these three systems. Static and dynamic polarizabilities of hydrated X2 clusters, X2.nH2O, are calculated and observed to vary linearly with the size (n) of these water clusters with correlation coefficient >0.999. This suggests that the polarizability of the larger size hydrated clusters can be reliably predicted. Static and dynamic polarizabilities of these hydrated clusters grow exponentially with the frequency of an external applied field for a particular size (n) of hydrated cluster.     

Vibrational distribution in NO(X2Pi) formed by self quenching of NO A 2Sigma+ (v=0)

Time-resolved FTIR has been used to study the emission from the NO X 2Pi (v) products formed both by fluorescence and by collisional self quenching of the NO A 2Sigma+ (v=0) state. Vibrational excitation has been observed in ground state NO with populations up to at least v=20. Under conditions where fluorescence is the dominant removal process the nascent distribution in ground state NO(v) was found to be determined by the relative magnitude of the emission coefficients. Collisional quenching by ground state NO populates higher vibrational levels in NO(v) than fluorescence. By comparing distributions acquired at different pressures and by using a surprisal analysis, a nascent distribution of NO(v=0-20) is estimated for collisional relaxation of NO A 2Sigma+ (v=0) by NO. This distribution was found to be slightly hotter than statistical (prior) and showed evidence of oscillations at specific vibrational levels. This work is one of the first to be published concerning the vibrational ground state products of the quenching of electronically excited molecules and the first to report emission over such a large number of vibrational levels.     

Ultrafast photochemical dissociation of an equatorial CO ligand from trans(X,X)-[Ru(X)2(CO)2(bpy)] (X = Cl, Br, I): a picosecond time-resolved infrared spectroscopic and DFT computational study

Ultrafast photochemistry of the complexes trans(X,X)-[Ru(X)(2)(CO)(2)(bpy)] (X = Cl, Br, I) was studied in order to understand excited-state reactivity of equatorial CO ligands, coordinated trans to the 2,2'-bipyridine ligand (bpy). TD-DFT calculations have identified the lowest electronic transitions and singlet excited states as mixed X -->bpy/Ru --> bpy ligand to ligand/metal to ligand charge transfer (LLCT/MLCT). Picosecond time-resolved IR spectroscopy in the region of nu(CO) vibrations has revealed that, for X = Cl and Br, subpicosecond CO dissociation is accompanied by bending of the X-Ru-X moiety, producing a pentacoordinated intermediate trans(X,X)-[Ru(X)(2)(CO)(bpy)]. Final movement of an axial halide ligand to the vacant equatorial position and solvent (CH(3)CN) coordination follows with a time constant of 13-15 ps, forming the photoproduct cis(X,X)-[Ru(X)(2)(CO)(CH(3)CN)(bpy)]. For X = I, the optically populated (1)LLCT/MLCT excited state undergoes a simultaneous subpicosecond CO dissociation and relaxation to a triplet IRuI-localized excited state which involves population of an orbital that is sigma-antibonding with respect to the axial I-Ru-I bonds. Vibrationally relaxed photoproduct cis(I,I)-[Ru(I)(2)(CO)(CH(3)CN)(bpy)] is formed with a time constant of ca. 55 ps. The triplet excited state is unreactive, decaying to the ground state with a 155 ps lifetime. The experimentally observed photochemical intermediates and excited states were assigned by comparing calculated (DFT) and experimental IR spectra. The different behavior of the chloro and bromo complexes from that of the iodo complex is caused by different characters of the lowest triplet excited states.     

From red to near infra-red OLEDs: the remarkable effect of changing from X = -Cl to -NCS in a cyclometallated [Pt(N^C^N)X] complex {N^C^N = 5-mesityl-1,3-di-(2-pyridyl)benzene}

[PtL(6)X] {X = Cl or NCS and L(6) = 5-mesityl-1,3-di(2-pyridyl)-benzene} display similar luminescence in solution but, in the solid state, the packing of the molecules is different, with short PtPt interactions for X = NCS, leading to a red-shifted emission band. The effect has been used to generate OLEDs that emit squarely in the NIR region (855 nm).     

Temperature dependent emission of hexarhenium(III) clusters [Re6(mu3-S)8X6]4- (X = Cl-, Br-, and I-): analysis by four excited triplet-state sublevels

Temperature (T) dependences of the emission spectra and lifetimes of hexarhenium(III) clusters, [Re6(mu3-S)8X6]4- (X = Cl-, Br-, and I-), in the crystalline phase were studied in detail. An increase in T from 30 to 70 K resulted in a red-shift of the emission spectrum of the cluster, while an increase in T above 70 K gave rise to a gradual blue-shift of the spectrum. On the other hand, the emission lifetime of the cluster decreased sharply from 30-40 to 13-20 micros on going from 30 to 60 K, while that decreased gradually above 60 K: 5-6 micros at 290 K. Such emission behaviors of [Re6(mu3-S)8X6]4- were observed irrespective of X. The results were then analyzed by assuming the contributions of the emissions from the lowest-energy excited triplet-state sublevels. The present study demonstrated that the characteristic T dependent emission spectra and lifetimes of [Re6(mu3-S)8X6]4- were explained reasonably by a single context of the contributions of the emissions from four excited triplet-state sublevels.     

Luminescence ranging from red to blue: a series of copper(I)-halide complexes having rhombic {Cu2(mu-X)2} (X = Br and I) units with N-heteroaromatic ligands

A series of Cu(I) complexes formulated as [Cu(2)(mu-X)(2)(PPh(3))(L)(n)] were prepared with various mono- and bidentate N-heteroaromatic ligands (X = Br, I; L = 4,4'-bipyridine, pyrazine, pyrimidine, 1,5-naphthyridine, 1,6-naphthyridine, quinazoline, N,N-dimethyl-4-aminopyridine, 3-benzoylpyridine, 4-benzoylpyridine; n = 1, 2). Single-crystal structure analyses revealed that all the complexes have planar {Cu(2)X(2)} units. Whereas those with monodentate N-heteroaromatic ligands afforded discrete dinuclear complexes, bidentate ligands formed infinite chain complexes with the ligands bridging the dimeric units. The long Cu...Cu distances (2.872-3.303 A) observed in these complexes indicated no substantial interaction between the two Cu(I) ions. The complexes showed strong emission at room temperature as well as at 80 K in the solid state. The emission spectra and lifetimes in the microsecond range were measured at room temperature and at 80 K. The emissions of the complexes varied from red to blue by the systematic selection of the N-heteroaromatic ligands (lambda(em)(max): 450 nm (L = N,N-dimethyl-4-aminopyridine) to 707 nm (L = pyrazine)), and were assigned to metal-to-ligand charge-transfer (MLCT) excited states with some mixing of the halide-to-ligand (XL) CT characters. The emission energies were successfully correlated with the reduction potentials of the coordinated N-heteroaromatic ligands, which were estimated by applying a simple modification based on the calculated stabilization energies of the ligands by protonation.     

Alternativ-Liganden. XXIII. Rhodium(I)-Komplexe mit Donor/Akzeptor-Liganden des Typs (Me2PCH2CH2SiX2 und (2-Me2PC6H4)SiXMe2 (X = F,Cl)

Alternative Ligands. XXIII Rhodium(I) Complexes with Donor/Acceptor Ligands of the Type (Me₂PCH₂CH₂)₂SiX₂ and (2-Me₂PC₆H₄)SiXMe₂ (X = F, Cl) Donor/acceptor ligands of the type (Me₂PCH₂CH₂)₂SiX₂ and (2-Me₂PC₆H₄)SiXMe₂ (X = F, Cl) react with [Rh(CO)₂Cl]₂ (₁) to give the mononuclear complexes RhCl(CO)(Me₂PCH₂CH₂)₂SiX₂ [X = F( 4 ), Cl ( 5 )] and RhCl(CO)[2-Me₂PC₆H₄)SixMe₂]₂ [X = F ( 8 ), Cl ( 9 )], respectively. In case of the ligands (Me₂PCH₂CH₂)₂SiCl₂ ( 3 ) and (2-Me₂PC₆H₆)SiClMe₂ ( 7 ) the Rh(I) complexes formed in the first step partly undergo oxidative addition reactions of SiCl bonds yielding rhodium(III) compounds of low solubility. Only for 8 the coordination shifts Δδ = δ(complex)?δ(ligand) and coupling constants give some indication to possible Rh→Si interactions. However, the molecular structure of 8 determined by X-ray diffraction does not show RhSi or RhF bonding contacts. The new compounds were characterized by analytical (C, H) and spectroscopic investigations (MS, IR,-NMR).     

Experimental and theoretical investigations of the reactions NH(X 3Sigma-) + D(2S)-->ND(X 3Sigma-) + H(2S) and NH(X 3Sigma-) + D(2S)-->N(4S) + HD(X 1Sigmag+)

The rate coefficient of the reaction NH(X (3)Sigma(-))+D((2)S)-->(k(1) )products (1) is determined in a quasistatic laser-flash photolysis, laser-induced fluorescence system at low pressures. The NH(X) radicals are produced by quenching of NH(a (1)Delta) (obtained in the photolysis of HN(3)) with Xe and the D atoms are generated in a D(2)/He microwave discharge. The NH(X) concentration profile is measured in the presence of a large excess of D atoms. The room-temperature rate coefficient is determined to be k(1)=(3.9+/-1.5) x 10(13) cm(3) mol(-1) s(-1). The rate coefficient k(1) is the sum of the two rate coefficients, k(1a) and k(1b), which correspond to the reactions NH(X (3)Sigma(-))+D((2)S)-->(k(1a) )ND(X (3)Sigma(-))+H((2)S) (1a) and NH(X (3)Sigma(-))+D((2)S)-->(k(1b) )N((4)S)+HD(X (1)Sigma(g) (+)) (1b), respectively. The first reaction proceeds via the (2)A(") ground state of NH(2) whereas the second one proceeds in the (4)A(") state. A global potential energy surface is constructed for the (2)A(") state using the internally contracted multireference configuration interaction method and the augmented correlation consistent polarized valence quadrupte zeta atomic basis. This potential energy surface is used in classical trajectory calculations to determine k(1a). Similar trajectory calculations are performed for reaction (1b) employing a previously calculated potential for the (4)A(") state. The calculated room-temperature rate coefficient is k(1)=4.1 x 10(13) cm(3) mol(-1) s(-1) with k(1a)=4.0 x 10(13) cm(3) mol(-1) s(-1) and k(1b)=9.1 x 10(11) cm(3) mol(-1) s(-1). The theoretically determined k(1) shows a very weak positive temperature dependence in the range 250< or =TK< or =1000. Despite the deep potential well, the exchange reaction on the (2)A(") ground-state potential energy surface is not statistical.     

PX4+, P2X5+, and P5X2+ (X=Br,I) salts of the superweak Al(OR)4- anion [R=C(CF3)3

PX(4) (+)[Al(OR)(4)](-) (X=I: 1 a, X=Br: 1 b) was prepared from X(2), PX(3), and Ag[Al(OR)(4)] [R=C(CF(3))(3)] in CH(2)Cl(2) at -30 degrees C in 69-86 % yield. P(2)X(5) (+) salts were prepared from 2 PX(3) and Ag[Al(OR)(4)] in CH(2)Cl(2) at -30 degrees C yielding almost quantitatively P(2)X(5) (+)[Al(OR)(4)](-) (X=I: 3 a, X=Br: 3 b). The phosphorus-rich P(5)X(2) (+) salts arose from the reaction of cold (-78 degrees C) mixtures of PX(3), P(4), and Ag[Al(OR)(4)] giving P(5)X(2) (+)[Al(OR)(4)](-) (X=I: 4 a, X=Br: 4 b) with a C(2v)-symmetric P(5) cage. Silver salt metathesis presumably generated unstable PX(2) (+) cations from PX(3) and Ag[Al(OR)(4)] (X=Br, I) that acted as electrophilic carbene analogues and inserted into the Xbond;X (Pbond;X/Pbond;P) bond of X(2) (PX(3)/P(4)) leading to the highly electrophilic and CH(2)Cl(2)-soluble PX(4) (+) (P(2)X(5) (+)/P(5)X(2) (+)) salts. Reactions that aimed to synthesize P(2)I(3) (+) from P(2)I(4) and Ag[Al(OR)(4)] instead led to anion decomposition and the formation of P(2)I(5)(CS(2))(+)[(RO)(3)Al-F-Al(OR)(3)](-) (5). All salts were characterized by variable-temperature solution NMR studies (3 b also by (31)P MAS NMR), Raman and/or IR spectroscopy as well as X-ray crystallography (with the exception of 4 a). The thermochemical volumes of the Pbond;X cations are 121 (PBr(4) (+)), 161 (PI(4) (+)), 194 (P(2)Br(5) (+)), 271 (P(2)I(5) (+)), and 180 A(3) (P(5)Br(2) (+)). The observed reactions were fully accounted for by thermochemical calculations based on (RI-)MP2/TZVPP ab initio results and COSMO solvation enthalpy calculations (CH(2)Cl(2) solution). The enthalpies of formation of the gaseous Pbond;X cations were derived as +764 (PI(4) (+)), +617 (PBr(4) (+)), +749 (P(2)I(5) (+)), +579 (P(2)Br(5) (+)), +762 (P(5)I(2) (+)), and +705 kJ mol(-1) (P(5)Br(2) (+)). The insertion of the intermediately prepared carbene analogue PX(2) (+) cations into the respective bonds were calculated, at the (RI-)MP2/TZVPP level, to be exergonic at 298 K in CH(2)Cl(2) by Delta(r)G(CH(2)Cl(2))=-133.5 (PI(4) (+)), -183.9 (PBr(4) (+)), -106.5 (P(2)I(5) (+)), -81.5 (P(2)Br(5) (+)), -113.2 (P(5)I(2) (+)), and -114.5 kJ mol(-1) (P(5)Br(2) (+)).     

The Jahn-Teller effect in CH(3)CN(+) (X(2)E) and CD(3)CN(+) (X(2)E) studied by zero kinetic energy photoelectron spectroscopy

The Jahn-Teller effect in CH(3)CN(+) (X(2)E) and CD(3)CN(+) (X(2)E) has been found experimentally by zero kinetic energy (ZEKE) photoelectron spectroscopy using coherent extreme ultraviolet (XUV) radiation. The vibronic bands of CH(3)CN(+) (X(2)E) and CD(3)CN(+) (X(2)E) at about 4500 cm(-1) above the ground states have been recorded. The spectra consist mainly of the Jahn-Teller active C-C[triple bond]N bending (v(8)), the CN stretching (v(2)), the CH(3) (CD(3)) deforming (v(6)), and the C-C stretching (v(4)) vibronic excitations. The Jahn-Teller active vibronic bands (v(8)) have been assigned with a harmonic model including linear and quadratic Jahn-Teller coupling terms, taking into account only the single mode vibronic excitation. The ionization potentials of CH(3)CN and CD(3)CN have also been determined, and their values are 12.2040(+/-0.001) and 12.2286(+/-0.001) eV, respectively.     

活性氮反应产生激发态卤化氮实验研究

A new method for producing electronically excited nitrogen monohalides NX(b) (X=F,Cl,Br) is reported. The strong emission spectra of NBr(b1Σ+→X3Σ–) are observed when alkyl bromides (CHBr3, CH2Br2, C2H5Br, and C4H9Br) are added to a stream of active nitrogen, generated by a hollow-cathode discharge of N2, in a flowing afterglow system. Some tentative experiments show that the electronically excited NBr(b) is formed by means of metastable N2(A3Σu+) Electronic-to-Electronic energy transfer to NBr(X), which is from the reaction of N(4S) with alkyl bromides. The emission spectra of NCl(b1Σ+→X3Σ–) are obtained when CCl4 or SOCl2 is admitted into a flow of active nitrogen, but neither CHCl3 nor CH2Cl2 addition results in such an emission. It has been proposed that the origin of the excited NCl(b) is an energy transfer from N2 (A) to NCl(X), generated by the reaction of N(4S) with CCl3 (or SOCl2). Similar experiments are also carried out with SF6 as reagent of active nitrogen, or as mixture with N2 in the discharge. By recording fluorescence it was found that excited NF(b) is produced only under discharge through N2/SF6 mixture. The NF(b) state presumably arises from the energy transfer from N2(A) to NF(X), and the latter is generated from the abstraction of fluorine by N(4S) from SF5.     

OXO (X=Cl,Br)与X (2P3/2)反应机理的理论研究

用密度泛函B3LYP/6-311+G**和高级电子相关的组态相互作用QCISD(T)/6-311+G**方法研究了OXO与X (2P3/2)双自由基反应的微观机理.研究结果表明该反应存在两个反应通道,产物分别为XO和X2+O2.由于形成产物XO的活化势垒较低,因而是主要反应通道,这与实验观察到的结果是一致的.而形成X2+O2的通道从动力学上看是不利的.     

Synthesis and Crystal Structures of Three Ladder Distannoxane Dimers [（PhCH2）2（Cl）SnOSn（X）（CH2Ph）2]2（X=Cl,OMe,OEt）

Three distannoxane dimers[(PhCH2)2(Cl)SnOSn(X)(CH2Ph)2]2(X=Cl,OMe,OEt)were prepared by the hydrolytic reaction of (PhCH2)2SnCl2 with sodium alkoxides.The compounds are assigned tetranuclear distannoxane structures in solid state.which contain the so-called ladder arrangement with a central planar Sn2O2 four-membered ring.The endo-and exo-cyclic Sn atoms are both five-coordinate,and have distorted trigonal bipyramidal geometries.A variety of hydrolyses of(PhCH2)2SnCl2 were performed and these dimers were characterized by IR,^1H NMR spectroscopy and X-ray diffraction analysis.