The photo-induced decarbonylation of Cp′M(NO)(CO)2 (M = Cr,Mo, W) with diorgano dichalcogenides (R2E2; E = S,Se; R = Me,Ph)

The photo-induced decarbonylation of CpCr(NO)(CO)₂ (1a) in MeCN solution in the presence of R₂E₂ (E = S, Se; R = Me, Ph) leads to the formation of chalcogenolato-bridged binuclear complexes Cp₂Cr₂(NO)₂(-ER)₂ [E = S; R = Me (2a), Ph (3a); E = Se, R = Me (4a), Ph (5a)] while reactions between CpM(NO)(CO)₂ [M = Mo (1b), W (1c)] and Ph₂E₂ (E = S, Se) result in mononuclear complexes CpM(NO)(EPh)₂ [M = Mo; E = S (9b), Se (10b); M = W, E = S (11c), Se (12c)]. The corresponding reactions of (1b) with Me₂E₂ (E = S, Se) yielded both mono and binuclear complexes: CpMo(NO)(SeMe)₂ (8b), Cp₂Mo₂(NO)₂(-EMe)₂ [E = S (6b), Se (7b)]. The new complexes have been characterized by i.r., ¹H-, ¹³C-n.m.r. spectra and by electron-impact mass spectrometry.     

Rhenium–Germanium Triple Bonds: Syntheses and Reactions of the Germylidyne Complexes mer‐[X2(PMe3)3ReGe?R] (X=Cl,I, H; R=m‐terphenyl)

A general approach to the first compounds that contain rhenium–germanium triple and double bonds is reported. Heating [ReCl(PMe₃)₅] ( 1 ) with the arylgermanium(II) chloride GeCl(C₆H₃‐2,6‐Trip₂) ( 2 ; Trip=2,4,6‐triisopropylphenyl) results in the germylidyne complex mer‐[Cl₂(PMe₃)₃Re?Ge? C₆H₃‐2,6‐Trip₂] ( 4 ) upon PMe₃ elimination. An equilibrium that is dependent on the PMe₃ concentration exists between complexes 1 and 4 . Removal of the volatile PMe₃ shifts the equilibrium towards complex 4 , whereas treatment of 4 with an excess of PMe₃ gives a 1:1 mixture of 1 and the PMe₃ adduct of 2 , GeCl(C₆H₃‐2,6‐Trip₂)(PMe₃) ( 2 ‐PMe₃). Adduct 2 ‐PMe₃ can be selectively obtained by addition of PMe₃ to chlorogermylidene 2 . The NMR spectroscopic data for 2 ‐PMe₃ indicate an equilibrium between 2 ‐PMe₃ and its dissociation products, 2 and PMe₃, which is shifted far towards the adduct site at ambient temperature. NMR spectroscopic monitoring of the reaction of complex 1 with 2 and the reaction of complex 4 with PMe₃ revealed the formation of two key intermediates, which were identified to be the chlorogermylidene complexes cis/trans‐[Cl(PMe₃)₄Re?Ge(Cl)C₆H₃‐2,6‐Trip₂] (cis/trans‐ 3 ) by using NMR spectroscopy. Labile chlorogermylidene complexes cis/trans‐ 3 can be also generated from trans‐[Cl(PMe₃)₄Re?Ge? C₆H₃‐2,6‐Trip₂]BPh₄ ( 9 ) and (nBu₄N)Cl at low temperature, and decompose at ambient temperature to give a mixture of complexes 1 and 4 . Complex 4 reacts with LiI to give the diiodido derivative mer‐[I₂(PMe₃)₃Re?Ge? C₆H₃‐2,6‐Trip₂] ( 5 ), which undergoes a metathetical iodide/hydride exchange with Na(BEt₃H) to give the dihydrido germylidyne complex mer‐[H₂(PMe₃)₃Re?Ge? C₆H₃‐2,6‐Trip₂] ( 6 ). Carbonylation of 4 induces a chloride migration from rhenium to the germanium atom to afford the chlorogermylidene complex mer‐[Cl(CO)(PMe₃)₃Re?Ge(Cl)C₆H₃‐2,6‐Trip₂] ( 7 ). Similarly, MeNC converts complex 4 into the methylisocyanide analogue mer‐[Cl(MeNC)(PMe₃)₃Re?Ge(Cl)C₆H₃‐2,6‐Trip₂] ( 8 ). Chloride abstraction from 4 by NaBPh₄ in the presence of PMe₃ gives the cationic germylidyne complex trans‐[Cl(PMe₃)₄Re?Ge? C₆H₃‐2,6‐Trip₂]BPh₄ ( 9 ). Heating complex 4 with cis‐[Mo(PMe₃)₄(N₂)₂] induces a germylidyne ligand transfer from rhenium to molybdenum to afford the germylidyne complex trans‐[Cl(PMe₃)₄Mo?Ge? C₆H₃‐2,6‐Trip₂] ( 10 ). All new compounds were fully characterized and their molecular structures studied by X‐ray crystallography, which led to the first experimentally determined Re? Ge triple‐ and double‐bond lengths.     

Formation of M(4)Se(4) cuboids (M = As, Sb, Bi) via secondary pnictogen-chalcogen interactions in the co-crystals MX(3)·Se[double bond, length as m-dash]P(p-FC(6)H(4))(3) (M = As, X = Br; M = Sb, X = Cl; M = Bi, X = Cl, Br)

The reactions of the group 15 trihalides, MX(3) (M = As, Sb, Bi; X = Cl, Br), with the phosphine selenide SeP(p-FC(6)H(4))(3) result in the formation of co-crystals of formula MX(3)·SeP(p-FC(6)H(4))(3). No reaction was observed with MI(3) (M = As, Sb, Bi). The structures of MX(3)·SeP(p-FC(6)H(4))(3) (M = As, X = Br 2; M = Sb, X = Cl 3; M = Bi, X = Cl 5; M = Bi, X = Br 6) have been established, and are isomorphous, crystallising in the cubic I23 space group. All the structures feature a primary MX(3) unit, which has three weak secondary MSe interactions to SeP(p-FC(6)H(4))(3) molecules. However, each of these SeP(p-FC(6)H(4))(3) molecules bridges three MX(3) molecules, resulting in the generation of an M(4)Se(4) (M = As, Sb, Bi) distorted cuboid linked by the pnictogen-chalcogen interactions. Four opposing corners of the cuboid are occupied by the M atom (M = As, Sb, Bi) of an MX(3) pyramid, and the other four by the selenium atom of the phosphine selenide.     

Synthesis and Anti-HIV Activity of Trisubstituted (3′R, 4′R)-3′,4′- Di-O-(S)-camphanoyl-(+)-cis-khellactone (DCK) Analogs

In our prior studies,3′,4′-di-O-(S)-camphanoyl-(+)-cis-khellactone(DCK,1,Figure1)and its derivatives including mono-and di-substituted DCK analogs were identified as a novel class of potent anti-HIV agents1-4.Because of its high potency and efficient syn-thesis,4-methyl-DCK25was chosen as a drug candidate for preclinical studies.How-ever,the low solubility and poor oral bioavailability of4-methyl-DCK limited its further development.Because high molecular hydrophobicity might be one re…     

The chemistry of [Ru(trpy)(Q)X]n+ (trpy = 2,2′2″-terpyridine; Q = the quinolin-8-olate anion; X = Cl-, H2O,MeCN and N-_3; n = 0 and 1)

Reaction of [Ru(trpy)Cl₃] with quinolin-8-ol (HQ) yields [Ru(trpy)(Q)Cl]. Treatment of [Ru(trpy)(Q)Cl] with Ag⁺ in Me₂CO–H₂O (3:1) and MeCN gives [Ru(trpy)- (Q)(H₂O)]⁺ and [Ru(trpy)(Q)(MeCN)]⁺, respectively, which were isolated as their perchlorate salts. A similar reaction in EtOH, in the presence of NaN₃, yields [Ru(trpy)(Q)(N₃)]. All complexes are diamagnetic (low-spin, d⁶, S = 0) and show many intense m.l.c.t. transitions in the visible region. They display a reversible Ru^II-Ru^III oxidation in the -0.13-0.48 V versus s.c.e. range, followed by an irreversible Ru^III-Ru^IV oxidation in the 0.46–1.08V versus s.c.e. range and three trpy-based reductions on the negative side of s.c.e. Chemical oxidation of [Ru^II(trpy)(Q)Cl] by Ce⁴⁺ gives [Ru(trpy)-(Q)Cl]⁺ which shows intense l.m.c.t. transitions in the visible region together with a weak ligand field transition in the lower energy region. The complex is one-electron paramagnetic (low-spin, d⁵, S=1/2) and shows a rhombic e.s.r. spectrum in MeCN–PhMe (1:1) solution at 77K. Chemical oxidation of [Ru(trpy)(Q)-(H₂O)]⁺ results in the formation of a -oxo dimer, [{Ru(trpy)(Q)}₂O]²⁺.     

Synthesis and Structure of Tetraphenylantimony Oximates Ph4SbON=CRR′ (CRR′ = C6H9−C6H9-2 and R = Ph,R′ = C(O)Ph)

The reaction of pentaphenylantimony and the oxime HON=CRR taken in 1 : 1 molar ratio in toluene gave tetraphenylantimony oximates Ph₄SbON=CRR (CRR = C₆H₉–C₆H₉-2 (I) and R = Ph, R = C(O)Ph (II)). According to X-ray diffraction data, the Sb atoms in I and II have a distorted trigonal-bipyramidal coordination with oximate ligands in the axial positions. The C_axSbO angles are 177.6(1)° in I and 176.58(6)° in II. The Sb–C bond lengths lie in the ranges of 2.120(4)–2.203(4) Å for I and 2.122(2)–2.181(2) Å for II. The Sb–O bond lengths are 2.120(2) Å (I) and 2.166(1) Å (II). The lengths of the intramolecular Sb···N contacts are 2.806(3) and 2.918(2) Å in I and II, respectively.     

Stannylenes: structures, electron affinities, ionization energies, and singlet-triplet gaps of SnX2/SnXY and XSnR/SnR2/RSnR′ species (X; Y = H, F, Cl, Br, I, and R; R' = CH3, SiH3, GeH3, SnH3)

Systematic computational studies of stannylene derivatives SnX(2)/SnXY and XSnR/SnR(2)/RSnR' were carried out using density functional theory. The basis sets used for H, F, Cl, Br, C, Si, and Ge atoms are of double-ζ plus polarization quality with additional s- and p-type diffuse functions, denoted DZP++. For the iodine and tin atoms, the Stuttgart-Dresden basis sets, with relativistic small-core effective core potentials (ECP), are used. All geometries are fully optimized with three functionals (BHLYP, BLYP, and B3LYP). Harmonic vibrational wavenumber analyses are performed to evaluate zero-point energy corrections and to determine the nature of the stationary points located. Predicted are four types of neutral-anion separations, plus adiabatic ionization energies (E(IE)) and singlet-triplet energy gaps (ΔE(S-T)). The dependence of all three energetic properties upon choice of substituent is remarkably strong. The EA(ad(ZPVE)) values (eV) obtained with the B3LYP functional range from 0.70 eV [Sn(CH(3))(2)] to 2.36 eV [SnI(2)]. The computed E(IE) values lie between 7.33 eV [Sn(SnH(3))(2)] and 11.15 eV [SnF(2)], while the singlet-triplet splittings range from 0.60 eV [Sn(SnH(3))(2)] to 3.40 eV [SnF(2)]. The geometries and energetics compare satisfactorily with the few available experiments, while most of these species are investigated for the first time. Some unusual structures are encountered for the SnXI(+) (X = F, Cl, and Br) cations. The structural parameters and energetics are discussed and compared with the carbene, silylene, and germylene analogues.     

Mixed Amidohalotantalates [Ta(NMe2)3X3]– (X = F,Cl)

Russian Journal of Coordination Chemistry - The anionic tantalum complex (ItBuH)[Ta(NMe2)3Cl3] (I) is synthesized by the reaction of [Ta(NMe2)3Cl2]2 with N-heterocyclic carbene ItBu and is isolated...     

Synthesis and structures of the six-coordinate donor-acceptor complexes R3(C6H4O2)Sb…L (R=Ph, L=OSMe2 or ONC5H5; R=Me, L=ONC5H5 or NC5H5) and R3(C2H4O2)Sb…L (R=Ph, L=ONC5H5; R=Cl or C6F5, L=OPPh3)

One-pot oxidation of R₃Sb (R=Ph, Me, Cl, or C₆F₅) withtert-butyl hydroperoxide in the presence of 1,2-diols and monodentate donor compounds was studied. The structures of the resulting neutral organic donor-acceptor Sb^V complexes, Ph₃(C₆H₄O₂)Sb…OSMe₂, Ph₃(C₆H₄O₂)Sb…ONC₅H₅, Me₃(C₆H₄O₂)Sb…ONC₅H₅, Me₃(C₆H₄O₂)Sb…NC₅H₅, Ph₃(C₂H₄O₂)Sb…ONC₅H₅, and Cl(C₆F₅)₂(C₂H₄O₂)Sb…OPPh₃, were established by X-ray diffraction analysis. In these complexes, the coordination environment about the Sb atoms is a distorted octahedron. The Sb?O(N) distances and the Sb?O?E angles (E=S, N, or P) vary over wide ranges.     

Bridge Cleavage Reactions of Dinuclear Diselenolenes: Preparation of Palladium Complexes of Novel Chelating Selenolato/Selenide Ligands, [PdX(Se{R′}CnH2n−4Se)(PR3)](n = 6, 7, 8; R = Ph,Bu; X = Br,I; R′ = Me,Et, etc.)

Abstract

The dinuclear palladium diselenolenes [Pd₂(Se₂C_nH_2n?4)₂(PR₃)₂] react with haloalkanes, via electrophilic attack at the bridging selenium atoms, to yield the neutral mononuclear square planar palladium(II) complexes [PdX(Se{R′}C_nH_2n?4Se)(PR₃)] (n = 6, 7, 8; R = Ph, Bu; X = Br, I; R′ = Me, Et, etc.), containing a novel chelating selenolato/selenide ligand, in which the alkylated selenium and halogen donor atoms occupy cis-positions. The products have been characterised by mass spectrometry and multinuclear NMR spectroscopy; the molecular structure of the compound with n = 8, R = Ph, R′ = Et has been determined by X-ray crystallography.     

Ce~(3+)在LnOX(Ln=La,Gd或Y;X=Cl,Br或I)中的发光

以激发光谱和发光光谱研究了Ce~(3+)在LnOX中的发光。光谱表明当X相同而Ln不同时,谱图上Ce~(3+)峰的位置只有较小的移动;而X不同时Ce~(3+)峰的位置有明显和有规律地移动,即按照Cl——Br——I次序往长波方向移动,这个次序与X的电负性减小的次序是一致的。还可以看到Ln=La时与Ln=Gd或Y时有差别,而且Ln=La时stokes位移较大,从离子半径角度对这些进行了讨论。     

MX2(AsH3)2(M=Pd,Pt;X=Cl,Br,I)的含时密度泛函理论研究

采用密度泛函方法(B3LYP)优化了MX2(AsH3)2[M=Pd；X=Cl(1)，Br(2)，I(3)和M=Pt；X=Cl(4)，Br(5)，I(6)]的基态结构，得到的几何参数与实验结果符合．以基态几何为基础，将TD-DFT方法用于计算标题配合物的电子吸收光谱．研究结果表明，金属的dx2-y2与配体所组成的反键轨道为LUMO轨道，从而该类配合物具有d-d跃迁属性的吸收带；在多数跃迁过程中，配体也有较大的贡献．     

Stereoselective synthesis and absolute configuration of (1′R,3R,4R)-4-acetoxy-3-(2′,2′,2′-trifluoro-1′-hydroxyethyl)azetidin-2-one

The title compound 3, an intermediate in the synthesis of fluorocarbapenems, is obtained with high stereocontrol by the condensation of (R)-(+)-ethyl 4,4,4-trifluoro-3-hydroxybutanoate with N-trimethylsilyl cinnamylidenimine. X-Ray diffraction analysis of the condensation product and chemical correlations allowed the unambiguous determination of the absolute configuration.     

Die indikatoreigenschaften des vicinalen m-Xylenolphthaleins (3′ ,5′ ,3′' ,5′'-Tetramethylphenolphthalein)

Ohne ZusammenfassungMit 1 Abbildung     

Ag(PPh3)nX(n=1,2,3；X=Cl,Br,I)的电化学合成

银配合物;;三苯基膦;电合成;Ag(PPh3)nX(n=1;2;3；X=Cl;Br;I)的电化学合成     

Interactions of M(z)-X complexes (M = Cu, Ag, and Au; X = He, Ne, and Ar; and z = ±1)

The coupled cluster singles and doubles method with perturbative treatment of triple excitations is applied to calculate the potentials of M(z)-X complexes (M = Cu, Ag, and Au; X = He, Ne, and Ar; and z = ±1). The bond functions and the basis set superposition errors are considered to obtain accurate interaction energies. The potential energy curves of all complexes are obtained. The vibrational energy levels and the spectroscopic parameters for these complexes are determined. The analytical potential energy functions are also fitted based on the potential energies.     

POSSIBLE HYDRIDE AND METHIDE TRANSFER REACTIONS: REACTIONS OF Fe(CO)4R−(R = H,CH3) AND W(CO)5R− (R = H,CH3, Cl,Br, I) WITH METAL CARBONYL CATIONS

Abstract

Reactions of metal carbonyl cations (M(CO)₆ ⁺, M = Mn, Re) with hydride-, methide- or halide-containing metal carbonyl anions (Fe(CO)₄R^?, R = H, Me; W(CO)₅R^?, R = H, Me, Cl, Br, I) produce products that indicate several mechanisms are operative. Reactions of the halo-tungsten complexes produce neutral, solvated tungsten complexes, W(CO)₅(CH₃CN) and W(CO)₄(CH₃CN)₂ and M(CO)₅X in a reaction that appears to be initiated by decomposition of W(CO)₅X^?. In contrast, the tungsten hydride and methide complexes react, predominantly, by transfer of the hydride or methide to a carbonyl of the cation at a much faster rate. The iron hydride and methide complexes react by iron-based nucleophilicity involving a two-electron process.     

LiY+NH2X(Y=F,Cl,Br,Br;X=F)反应机理的计算研究

一百多年来,无论从实验还是理论上,气相中碳原子上SN2的反应机理都已经得到了广泛的深入研究.近二十几年来,杂原子上的亲核取代反应由于其在生物有机及在人体代谢过程中所起的重要作用而逐渐引起人们的关注.氮原子上的SN2反应是近年来的研究热点,但其中的亲核试剂仅局限于阴离子[1].本文将研究对象扩展到离子对亲核取代反应[2].我们在B3LYP/6-311+G(d,p)水平上讨论了气相中LiY+NH2X(Y=F,Cl,Br,I;X=F)的反应机理,希望能为实验化学家提供有价值的信息.     

M_2RSbO_6:R′~(3+)(M=Ba,Sr,Ca;R=La,Gd,Y,Bi;R′=Sm,Eu,Dy,Ho,Er,Tm)复合氧化物的合成,组成,结构和荧光性质

本文按文献的方法合成了Ba-2BiSbO_6,Ba_2GdSbO_6、M_2RSbO_6(M=Ba,Sr,Ca,R=La,Y),以M_2RSbO_6为基质掺Sm~(3+)、En~(3+)、Dy~(3+)、Ho~(3+)、Er~(3+)、Tm~(3+)、Bi~(3+)研究它们的化学组成,晶体结构与发光性能的关系及规律,Bi~(3+)的荧光及敏化作用,同时研究了它们