Theoretical study on the isomeric structures and the stability of silylenoid (Tsi)Cl2SiLi (Tsi = C(SiMe3)3)

The structures and isomerization of silylenoid (Tsi)Cl(2)SiLi (Tsi = C(SiMe(3))(3)) were studied by density functional theory (DFT) at the B3LYP/6-31G(d) level. Four equilibrium structures and three isomeric transition states were located. The three-membered ring and p-complex structures, 1 and 2, are the two most stable forms. Two other local minima, the sigma-complex 3 and tetrahedron structure 4, should rearrange to 1 with very low barriers, and then to the most stable isomer 2. To exploit further the stability of silylenoid (Tsi)Cl(2)SiLi, the insertion reactions of 2 and silylene (Tsi)ClSi into the HF molecule have been investigated at the B3LYP/6-31G(d) level, respectively. The results show that the insertion of 2 into HF is very similar to that of (Tsi)ClSi into HF, but the latter is more favorable. To probe the influence of the substituent Tsi on the stability of silylenoid (Tsi)Cl(2)SiLi, the isomers and insertion reaction of silylenoid CH(3)Cl(2)SiLi were investigated in a similar way of those with (Tsi)Cl(2)SiLi. The results indicate that silylenoid containing very bulky group Tsi exhibits unusual stability because of the severe steric hindrance produced by Tsi at the center to which it is attached.     

类硅烯H2C＝SiLiBr与RH (R＝F, OH, NH2)的插入反应

采用DFT B3LYP和QCISD方法研究了类硅烯H2C＝SiLiBr与RH (R＝F, OH, NH2)的插入反应. 在B3LYP/6- 311＋G(d,p)水平上优化了反应势能面上的驻点构型. 结果表明, H2C＝SiLiBr与HF, H2O或NH3发生插入反应的机理相同. QCISD/6-311＋＋G(d,p)//B3LYP/6-311＋G(d,p)计算的三个反应的势垒分别为148.62, 164.42和165.07 kJ•mol－1, 反应热分别为－69.63, －43.02和－28.27 kJ•mol－1. 相同条件下发生插入反应时, 反应活性都是H—F＞H—OH＞H—NH2.     

Isomers and [2,3]-Sila-wittig Rearrangement of [（Allyloxy）silyl]lithium Silylenoid in the Gas Phase and THF Solvent

Theoretical calculations of the [2,3]-sila-wittig rearrangement of isomers of [（allyloxy）silyl]lithium （C3H5O）HzSiLi have been performed in the gas phase and THF solvent using the G3MP2B3 method. Seven isomers of silylenoid （C3H5O）H2SiLi, 1-7, are found. The [2,3]-silawittig rearrangement paths are followed using two isomers, 2 and 4, to yield the transition states as well as the products. In the transition state, the silicon center functions as a nucleophile and the aUyl as an electrophile. The interaction between the silicon and allylic sites leads to the formation of SiC（3） bond and the break of O-C（1） bond. Finally, the （allylsilyl）oxylithium （C3H5）H2SiOLi is obtained. The rearrangement paths are confirmed by the intrinsic reaction coordinate （IRC） calculations. The rearrangement mechanisms of reactions of 2 and 4 are similar, and the latter reaction is more favored in the gas phase and THF solvent. Also, the solvent effects are analyzed in this work.     

Theoretical study on the substitution reactions of silylenoid H2SiLiF with CH4, NH3, H2O, HF, SiH4, PH3, H2S, and HCl

DFT calculations at the B3LYP/6-31G(d,p) level have been performed to explore the substitution reactions of silylenoid H(2)SiLiF with XH(n) hydrides, where XH(n) = CH(4), NH(3), H(2)O, HF, SiH(4), PH(3), H(2)S, and HCl. We have identified a previously unreported reaction pathway on each reaction surface, H(2)SiLiF + XH(n) --> H(3)SiF + LiXH(n-1), which involved the initial formation of an association complex via a five-membered cyclic transition state to form an intermediate followed by the substituted product H(3)SiF with LiXH(n-1) dissociating. These theoretical calculations suggest that (i) there is a very clear trend toward lower activation barriers and more exothermic interactions on going from left to right along a given row in the periodic table, and (ii) for the second-row hydrides, the substitution reactions are more exothermic than for the first-row hydrides and the reaction barriers are lower. The solvent effects were considered by means of the polarized continuum model (PCM) using THF as a solvent. The presence of THF solvent disfavors slightly the substitution reaction. Compared to the previously reported insertions and H(2)-elimination reactions of H(2)SiLiF and XH(n), the substitution reactions should be most favorable.     

Ruthenium(II) ammine and hydrazine complexes with [N(Ph2PQ)2]- (Q = S, Se) ligands

Reactions of coordinatively unsaturated Ru[N(Ph2PQ)2]2(PPh3) (Q = S (1), Se (2)) with pyridine (py), SO2, and NH3 afford the corresponding 18e adducts Ru[N(Ph2PQ)2]2(PPh3)(L) (Q = S, L = NH3 (5); Q = Se, L = py (3), SO2 (4), NH3 (6)). The molecular structures of complexes 2 and 6 are determined. The geometry around Ru in 2 is pseudo square pyramidal with PPh3 occupying the apical position, while that in 6 is pseudooctahedral with PPh3 and NH3 mutually cis. The Ru-P distances in 2 and 6 are 2.2025(11) and 2.2778(11) A, respectively. The Ru-N bond length in 6 is 2.185(3) A. Treatment of 1 or 2 with substituted hydrazines L or NH2OH yields the respective adducts Ru[N(Ph2PQ)2]2(PPh3)(L) (Q = S, L = NH2NH2 (12), t-BuNHNH2 (14), l-aminopiperidine (C5H10NNH2) (15); Q = Se, L = PhCONHNH2 (7), PhNHNH2 (8), NH2OH (9), t-BuNHNH2 (10), C5H10NNH2 (11), NH2NH2 (13)), which are isolated as mixtures of their trans and cis isomers. The structures of cis-14 and cis-15 are characterized by X-ray crystallography. In both molecular structures, the ruthenium adopts a pseudooctahedral arrangement with PPh3 and hydrazine mutually cis. The Ru-N bond lengths in cis-14.CH2Cl2 and cis-15 are 2.152(3) and 2.101(3) A, respectively. The Ru-N-N bond angles in cis-14.CH2Cl2 and cis-15 are 120.5(4) and 129.0(2) degrees, respectively. Treatment of 1 with hydrazine monohydrate leads to the isolation of yellow 5 and red trans-Ru[N(Ph2PS)2]2(NH3)(H2O) (16), which are characterized by mass spectrometry, 1H NMR spectroscopy, and elemental analyses. The geometry around ruthenium in 16 is pseudooctahedral with the NH3 and H2O ligands mutually trans. The Ru-O and Ru-N bond distances are 2.118(4) and 2.142(6) A, respectively. Oxidation reactions of the above ruthenium hydrazine complexes are also studied.     

Isomers and [2,3]-Sila-wittig Rearrangement of [(Allyloxy)sily]lithium Silylenoid in the Gas Phase and THF Solvent

Theoretical calculations of the [2,3]-sila-wittig rearrangement of isomers of [(allyl-oxy)silyl]lithium (C3H50)H2SiLi have been performed in the gas phase and THF solvent using theG3MP2B3 method.Seven isomers of silylenoid (C3H5O)H2SiLi, 1～7, are found.The [2,3]-sila-wittig rearrangement paths are followed using two isomers, 2 and 4, to yield the transition states as well as the products.In the transition state, the silicon center functions as a nucleophile and the allyl as an electrophile.The interaction between the silicon and allylic sites leads to the formation of Si-C[3] bond and the break of O-C[1] bond.Finally, the (allylsilyl)oxylithium (C3H5)H2SiOLi is obtained.The rearrangement paths are confirmed by the intrinsic reaction coordinate (IRC)calculations.The rearrangement mechanisms of reactions of 2 and 4 are similar, and the latter reaction is more favored in the gas phase and THF solvent.Also, the solvent effects are analyzed in this work.     

类锗烯H2C=GeLiCl与RH(R=F,OH, NH2)的插入反应

采用DFT B3LYP和QCISD方法研究了不饱和类锗烯H2C=GeLiCl与RH(R=F, OH, NH2)的插入反应. 在B3LYP/6-311+G(d,p)水平上优化了反应势能面上的驻点构型. 结果表明, H2C=GeLiCl与HF、H2O 或NH3发生插入反应的机理相同. QCISD/6-311++G(d,p)//B3LYP/6-311+G(d,p)计算的三个反应的势垒分别为173.53、194.48和209.05 kJ·mol-1, 反应热分别为60.18、72.93和75.34 kJ·mol-1. 相同条件下发生插入反应时, 反应活性顺序都是H—F>H—OH>H—NH2.     

Mild, Reversible Reaction of Iridium(III) Amido Complexes with Carbon Dioxide

Unlike some other Ir(III) hydrides, the aminopyridine complex [(2-NH(2)-C(5)NH(4))IrH(3)(PPh(3))(2)] (1-PPh(3)) does not insert CO(2) into the Ir-H bond. Instead 1-PPh(3) loses H(2) to form the cyclometalated species [(κ(2)-N,N-2-NH-C(5)NH(4))IrH(2)(PPh(3))(2)] (2-PPh(3)), which subsequently reacts with CO(2) to form the carbamato species [(κ(2)-O,N-2-OC(O)NH-C(5)NH(4))IrH(2)(PPh(3))(2)] (10-PPh(3)). To study the insertion of CO(2) into the Ir-N bond of the cyclometalated species, a family of compounds of the type [(κ(2)-N,N-2-NR-C(5)NH(4))IrH(2)(PR'(3))(2)] (R = H, R' = Ph (2-PPh(3)); R = H, R' = Cy (2-PCy(3)); R = Me, R' = Ph (4-PPh(3)); R = Ph, R' = Ph (5-PPh(3)); R = Ph, R' = Cy (5-PCy(3))) and the pyrimidine complex [(κ(2)-N,N-2-NH-C(4)N(2)H(3))IrH(2)(PPh(3))(2)] (6-PPh(3)) were prepared. The rate of CO(2) insertion is faster for the more nucleophilic amides. DFT studies suggest that the mechanism of insertion involves initial nucleophilic attack of the nitrogen lone pair of the amide on CO(2) to form an N-bound carbamato complex, followed by rearrangement to the O-bound species. CO(2) insertion into 1-PPh(3) is reversible in the presence of H(2) and treatment of 10-PPh(3) with H(2) regenerates 1-PPh(3), along with Ir(PPh(3))(2)H(5).     

Reactivity of a coordinatively unsaturated Cp*Ru(kappa2-P,O) complex

Whereas a new coordinatively unsaturated Cp*Ru(kappa(2)-P,O) complex (1a) forms adducts with two-electron donors (including sigma-H(2) and mu-N(2) ligands), double Si-H bond activation is observed upon treatment with Ph(2)SiH(2) or PhSiH(3), leading to the clean formation of products corresponding to the net insertion of a Ph(2)Si: or Ph(H)Si: fragment into the Ru-O bond of 1a.     

Reactions of CF3CH2I+O(3P): competing mechanisms of HF elimination

Ab initio density functional and molecular orbital calculations provide singlet and triplet electronic potential energy surfaces for the reactions of CF3CH2I+O(3P) leading to OI and HF eliminations, reactions which have been the subject of recent experimental studies. A barrier to OI formation occurs on the triplet potential energy surface; there is no reverse barrier to OI formation on the singlet pathway. Findings suggest that two competing pathways may form HF. One is an addition-insertion-elimination process involving insertion of O into the C-I bond. The alternate path involves OI elimination, addition of an O atom to CF3CH2, and subsequent HF elimination. The computed reactant pathways and energetics are discussed in relation to recent experiments.     

钠氟类硅烯插入RH键(R=F,OH,NH2,CH3)反应的理论研究

用密度泛函方法研究了钠氟类硅烯插入R_H键(R=F,OH,NH2,CH3)的反应机理.4个反应的机制类似,反应经历了类硅烯的亲电接近、亲核插入和取代三个阶段之后,形成中间络合物,4个反应的势垒分别为0.9,61.7,114.6和190.6kJ/mol(经零点能校正).中间络合物可以解离为取代硅烷和NaF,这是一个无过渡态的过程.反应能分别是-122.6,-96.3,-6.8和50.2kJ/mol.     

Unsaturated Ru(0) species with a constrained bis-phosphine ligand: [Ru(CO)2(tBu2PCH2CH2PtBu2)]2. Comparison to [Ru(CO)2(PtBu2Me)2

The synthesis of Ru(C2H4)(CO)2(dtbpe) (dtbpe = tBu2PC2H4PtBu2), then green [Ru(CO)2(dtbpe)]n is described. In solution, n = 1, while in the solid state, n = 2; the dimer has two carbonyl bridges. DFTPW91, MP2, and CCSD(T) calculations show that the potential energy surface for bending one carbonyl out of the RuP2C(O) plane is essentially flat. Ru(CO)2(dtbpe) reacts rapidly in benzene solution to oxidatively add the H-E bond of H2, HCl, HCCR (R = H, Ph), [HOEt2]BF4, and HSiEt3. The H-C bond of C6HF5 oxidatively adds at 80 degrees C. CO adds, as does the C=C bond of H2C=CHX (X = H, F, Me). The following do not add: N2, THF, acetone, H3COH, and H2O.     

Slow hydrogen atom self-exchange between Os(IV) anilide and Os(III) aniline complexes: relationships with electron and proton transfer self-exchange

Hydrogen atom, proton and electron transfer self-exchange and cross-reaction rates have been determined for reactions of Os(IV) and Os(III) aniline and anilide complexes. Addition of an H-atom to the Os(IV) anilide TpOs(NHPh)Cl(2) (Os(IV)NHPh) gives the Os(III) aniline complex TpOs(NH(2)Ph)Cl(2) (Os(III)NH(2)Ph) with a new 66 kcal mol(-1) N-H bond. Concerted transfer of H* between Os(IV)NHPh and Os(III)NH(2)Ph is remarkably slow in MeCN-d(3), with k(ex)(H*) = (3 +/- 2) x 10(-3) M(-1) s(-1) at 298 K. This hydrogen atom transfer (HAT) reaction could also be termed proton-coupled electron transfer (PCET). Related to this HAT process are two proton transfer (PT) and two electron transfer (ET) self-exchange reactions, for instance, the ET reactions Os(IV)NHPh + Os(III)NHPh(-) and Os(IV)NH(2)Ph(+) + Os(III)NH(2)Ph. All four of these PT and ET reactions are much faster (k = 10(3)-10(5) M(-1) s(-1)) than HAT self-exchange. This is the first system where all five relevant self-exchange rates related to an HAT or PCET reaction have been measured. The slowness of concerted transfer of H* between Os(IV)NHPh and Os(III)NH(2)Ph is suggested to result not from a large intrinsic barrier but rather from a large work term for formation of the precursor complex to H* transfer and/or from significantly nonadiabatic reaction dynamics. The energetics for precursor complex formation is related to the strength of the hydrogen bond between reactants. To probe this effect further, HAT cross-reactions have been performed with sterically hindered aniline/anilide complexes and nitroxyl radical species. Positioning steric bulk near the active site retards both H* and H(+) transfer. Net H* transfer is catalyzed by trace acids and bases in both self-exchange and cross reactions, by stepwise mechanisms utilizing the fast ET and PT reactions.     

三重态类硅烯HB＝SiLiF的结构及其与R—H(R=F,OH,NH_2)的插入反应

用密度泛函理论(DFT)和二次组态相互作用(QCISD)方法研究了三重态类硅烯HB=SiLiF的结构及其与RH(R=F,OH,NH2)的插入反应.计算结果表明,类硅烯HB=SiLiF有三种平衡构型,其中四元环构型能量最低,是其存在的主要构型.HB=SiLiF与HF,H2O和NH3发生插入反应的机理相同.QCISD/6-311++G(d,p)//B3LYP/6-311+G(d,p)计算的三个反应的势垒分别为124.85,140.67和148.16kJ·mol-1,反应热分别为-2.22,20.08和23.22kJ·mol-1.相同条件下发生插入反应时,反应活性都是H—FH—OHH—NH2.     

Vibrational analysis of Ag3(PO2NH)3, Na3(PO2NH)3 x H2O, Na3(PO2NH)3 x 4H2O,

FT IR and FT Raman spectra of Ag3(PO2NH), (Compound 1), Na3(PO2NH)3 x H2O (Compound II), Na3(PO2NH)3 x 4H2O (Compound III), [C(NH2)3]3(PO2NH)3 x H2O (Compound IV) and (NH4)4(PO2NH)4 x 4H2O (Compound V) are recorded and analyzed on the basis of the anions, cations and water molecules present in each of them. The PO2NH- anion ring in compound I is distorted due to the influence of Ag+ cation. Wide variation in the hydrogen bond lengths in compound III is indicated by the splitting of the v2 and v3 modes of vibration of water molecules. The NH4 ion in compound V occupies lower site symmetry and exhibits hindered rotation in the lattice. The correlations between the symmetric and asymmetric stretching vibrations of P-N-P bridge and the P-N-P bond angle have also been discussed.     

Molybdenum amido complexes with single Mo-N bonds: synthesis,structure, and reactivity

Reactions of the complex [MoCl(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)] (1) (phen=1,10-phenanthroline) with potassium arylamides were used to synthesize the amido complexes [Mo(N(R)Ar)(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)] (R=H, Ar=Ph, 2 a; R=H, Ar=p-tolyl, 2 b; R=Me, Ar=Ph; 2 c). For 2 b the Mo-N(amido) bond length (2.105(4) A) is consistent with it being a single bond, with which the metal attains an 18-electron configuration. The reaction of 2 b with HOTf affords the amino complex [Mo(eta(3)-C(3)H(4)-Me-2)(NH(2)(p-tol))(CO)(2)(phen)]OTf (3-OTf). Treatment of 3-OTf with nBuLi or KN(SiMe(3))(2) regenerates 2 b. The new amido complexes react with CS(2), arylisothiocyanates and maleic anhydride. A single product corresponding to the formal insertion of the electrophile into the Mo-N(amido) bond is obtained in each case. For maleic anhydride, ring opening accompanied the formation of the insertion product. The reaction of 2 b with maleimide affords [Mo(eta(3)-C(3)H(4)-Me-2)[NC(O)CH=CHC(O)](CO)(2)(phen)] (7), which results from simple acid-base metathesis. The reaction of 2 b with (p-tol)NCO affords [[Mo(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)](2)(eta(2)-MoO(4))] (8), which corresponds to oxidation of one third of the metal atoms to Mo(VI). Complex 8 was also obtained in the reactions of 2 b with CO(2) or the lactide 3,6-dimethyl-1,4-dioxane-2,5-dione. The structures of the compounds 2 b, 3-OTf, [Mo(eta(3)-C(3)H(4)-Me-2)[SC(S)(N(H)Ph)](CO)(2)(phen)] (4), [Mo(eta(3)-C(3)H(4)-Me-2)[SC(N(p-tol))(NH(p-tol))](CO)(2)(phen)] (5 a), and [Mo(eta(3)-C(3)H(4)-Me-2)[OC(O)CH=CHC(O)(NH(p-tol))](CO)(2)(phen)] (6), 7, and 8 (both the free complex and its N,N'-di(p-tolyl)urea adduct) were determined by X-ray diffraction.     

Mechanistic insight into hydrosilylation reactions catalyzed by high valent ReX (X = O, NAr, or N) complexes: the silane (Si-H) does not add across the metal-ligand multiple bond

Treatment of oxo and imido-rhenium(V) complexes Re(X)Cl3(PR3)2 (X = O, NAr, and R = Ph or Cy) (1-2) with Et3SiH affords Re(X)Cl2(H)(PR3)2 in high yields. Cycloaddition of silane across the ReX multiple bonds is not observed. Two rhenium(V) hydrides (X = O and R = Ph, 4a; X = NMes and R = Ph, 5a) have been structurally characterized by X-ray diffraction. The kinetics of the reaction of Re(O)Cl3(PPh3)2 (1a) with Et3SiH is characterized by phosphine inhibition and saturation in [Et3SiH]. Hence, formation of Re(O)Cl2(H)(PPh3)2 (4a) proceeds via a sigma-adduct followed by heterolytic cleavage of the Si-H bond and transfer of silylium (Et3Si+) to chloride. Oxo and imido complexes of rhenium(V) (1-2) as well as their nitrido analogues, Re(N)Cl2(PR3)2 (3), catalyze the hydrosilylation of PhCHO under ambient conditions, with the reactivity order imido > oxo > nitrido. The isolable oxorhenium(V) hydride 4a reacts with PhCHO to afford the alkoxide Re(O)Cl2(OCH2Ph)(PPh3)2 (6a) with kinetic dependencies that are consistent with aldehyde coordination followed by aldehyde insertion into the Re-H bond. The latter (6a) regenerates the rhenium hydride upon reaction with Et3SiH. These stoichiometric reactions furnish a possible catalytic cycle. However, quantitative kinetic analysis of the individual stoichiometric steps and their comparison to steady-state kinetics of the catalytic reaction reveal that the observed intermediates do not account for the predominant catalytic pathway. Furthermore, for Re(O)Cl2(H)(PCy3)2 and Re(NMes)Cl2(H)(PPh3)2 aldehyde insertion into the Re-H bond is not observed. Therefore, based on the kinetic dependencies under catalytic conditions, a consensus catalytic pathway is put forth in which silane is activated via sigma-adduct formation cis to the ReX bond followed by heterolytic cleavage at the electrophilic rhenium center. The findings presented here demonstrate the so-called Halpern axiom, the observation of "likely" intermediates in a catalytic cycle, generally, signals a nonproductive pathway.     

Reactions of (PCP)Ru(CO)(NHPh)(PMe3) (PCP = 2,6-(CH2PtBu2)2C6H3) with substrates that possess polar bonds

The Ru(II) amido complex (PCP)Ru(CO)(PMe(3))(NHPh) (1) (PCP = 2,6-(CH(2)P(t)Bu(2))(2)C(6)H(3)) reacts with compounds that possess polar C=N, C triple bond N, or C=O bonds (e.g., nitriles, carbodiimides, or isocyanates) to produce four-membered heterometallacycles that result from nucleophilic addition of the amido nitrogen to an unsaturated carbon of the organic substrate. Based on studies of the reaction of complex 1 with acetonitrile, the transformations are suggested to proceed by dissociation of trimethylphosphine, followed by coordination of the organic substrate and then intramolecular N-C bond formation. In the presence of ROH (R = H or Me), the fluorinated amidinate complex (PCP)Ru(CO)(N(Ph)C(C(6)F(5))NH) (6) reacts with excess pentafluorobenzonitrile to produce (PCP)Ru(CO)(F)(N(H)C(C(6)F(5))NHPh) (7). The reaction with MeOH also produces o-MeOC(6)F(4)CN (>90%) and p-MeOC(6)F(4)CN (<10%). Details of the solid-state structures of (PCP)Ru(CO)(F)(N(H)C(C(6)F(5))NHPh) (7), (PCP)Ru(CO)[PhNC{NH(hx)}N(hx)] (8), (PCP)Ru(CO){N(Ph)C(NHPh)O} (9), and (PCP)Ru(CO){OC(Ph)N(Ph)} (10) are reported.     

Insertion reactions of hydridonitrosyltetrakis(trimethylphosphine) tungsten(0)

[W(H)(NO)(PMe3)4] (1) was prepared by the reaction of [W(Cl)(NO)(PMe3)4] with NaBH4 in the presence of PMe3. The insertion of acetophenone, benzophenone and acetone into the W-H bond of 1 afforded the corresponding alkoxide complexes [W(NO)(PMe3)4(OCHR1R2)](R1 = R2 = Me (2); R1 = Me, R2 = Ph (3); R1 = R2 = Ph (4)), which were however thermally unstable. Insertion of CO2 into the W-H bond of yields the formato-O complex trans-W(NO)(OCHO)(PMe3)4 (5). Reaction of trans-W(NO)(H)(PMe3)4 with CO led to the formation of mer-W(CO)(NO)(H)(PMe3)3 (6) and not the formyl complex W(NO)(CHO)(PMe3)4. Insertion of Fe(CO)(5), Re2(CO)10 and Mn2(CO)10 into trans-W(NO)(H)(PMe3)4 resulted in the formation of trans-W(NO)(PMe3)4(mu-OCH)Fe(CO)4 (7), trans-W(NO)(PMe3)4(mu-OCH)Re2(CO)9 (8) and trans-W(NO)(PMe3)4(mu-OCH)Mn2(CO)9 (9). For Re2(CO)10, an equilibrium was established and the thermodynamic data of the equilibrium reaction have been determined by a variable-temperature NMR experiments (K(298K)= 104 L mol(-1), DeltaH=-37 kJ mol(-1), DeltaS =-86 J K(-1) mol(-1)). Both compounds 7 and 8 were separated in analytically pure form. Complex 9 decomposed slowly into some yet unidentified compounds at room temperature. Insertion of imines into the W-H bond of 1 was also additionally studied. For the reactions of the imines PhCH=NPh, Ph(Me)C=NPh, C6H5CH=NCH2C6H5, and (C6H5)2C=NH with only decomposition products were observed. However, the insertion of C10H7N=CHC6H5 into the W-H bond of led to loss of one PMe3 ligand and at the same time a strong agostic interaction (C17-H...W), which was followed by an oxidative addition of the C-H bond to the tungsten center giving the complex [W(NO)(H)(PMe3)3(C10H6NCH2Ph)] (10). The structures of compounds 1, 4, 7, 8 and 10 were studied by single-crystal X-ray diffraction.     

Supramolecular aggregation of mononuclear triorganophosphinegold(I) 2-mercaptobenzamides: solution structures, thermal decomposition, and photoluminescence

The crystal structures of R3PAu[SC6H4C(=O)NH2-2], R = Et (1), Ph (2), and Cy (3) show linear coordination geometries for gold defined by sulfur and phosphorus atoms. Supramolecular aggregation via {...H-N-C=O}2 synthons lead to dimeric aggregates in each case. In (1) and (2), the aggregates are spherical, but steric effects exerted by cyclohexyl rings in (3) dictate a rodlike form; no Au...Au interactions were noted in the crystal structures. Solvent dependence in their NMR spectra is correlated with intra- and intermolecular hydrogen bonding. The compounds uniformly decompose under controlled conditions to give gold. The complexes excited by UV light produce strong blue-green luminescence. The configuration interaction singles (CIS) post-Hartree-Fock (HF) calculations for the compounds indicate that it is the charge transfer from the sulfur and pi-orbitals of SC6H4C(=O)NH2-2 to gold that produce the emission from gold. The assignment of the observed luminescence is presented in terms of the relaxed excited states of gold, in which the vibronic interactions for three p-orbitals of gold are taken into account.