Theoretical study of electronic spectra of [Pt3(μ‐CO)3(CO)3] (n = 3–5) complexes

The platinum‐platinum attraction and the spectroscopic properties of [Pt₃(μ‐CO)₃(CO)₃] (n = 3–5) were studied at the PBE level. Theoretical calculations are in agreement with experimental geometries. The absorption spectra of these platinum complexes were calculated by the single excitation time‐dependent (TD) density functional method. All complexes showed MLCT transitions interrelated with the intertriangular complexes. The values obtained at the PBE level are in agreement with the experimental color range. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009     

Darstellung von Trifluormethylhalogen-Iodaten(I) des Typs (CH3)4N+CF3IX− (X = F,Cl, Br) und Trifluormethyltrifluormethoxyiodat(I) (CH3)4N+CF3IOCF3−

Preparation of Trifluormethylhalogen Iodate(I) Salts (CH₃)₄N⁺CF₃IX^? (X = F, Cl, Br) and Trifluormethyltrifluormethoxy Iodate(I) (CH₃)₄N⁺CF₃IOCF₃^? We describe the preparation of new trifluormethyliodate(I) salts CF₃IX^? (X = F, Cl, Br, OCF₃). (CH₃)₄N⁺CF₃ICl^? and (CH₃)₄N⁺CF₃IBr^? are obtained via addition of CF₃I with the corresponded tetramethylammonium halogenide. (CH₃)₄N⁺CF₃IOCF₃^? is synthesized by comproportionation of (CH₃)₄N⁺CF₃ICl^? with CF₃OCl under formation of Cl₂ at ?78°C. (CH₃)₄N⁺CF₃IF^? is formed either, through thermolysis of (CH₃)₄N⁺ CF₃IOCF₃^? under separation of COF₂, or reaction of CF₃I with (CH₃)₄N⁺ OCF₃^?. The thermolabile compounds have been characterized by i.r., Raman, ¹⁹F-, ¹³C NMR spectroscopy.     

Luminescent Di‐ and Polynuclear Organometallic Gold(I)–Metal (Au2, {Au2Ag}n and {Au2Cu}n) Compounds Containing Bidentate Phosphanes as Active Antimicrobial Agents

The reaction of new dinuclear gold(I) organometallic complexes containing mesityl ligands and bridging bidentate phosphanes [Au₂(mes)₂(μ‐LL)] (LL=dppe: 1,2‐bis(diphenylphosphano)ethane 1 a , and water‐soluble dppy: 1,2‐bis(di‐3‐pyridylphosphano)ethane 1 b ) with Ag⁺ and Cu⁺ lead to the formation of a family of heterometallic clusters with mesityl bridging ligands of the general formula [Au₂M(μ‐mes)₂(μ‐LL)][A] (M=Ag, A=ClO₄^?, LL=dppe 2 a , dppy 2 b ; M=Ag, A=SO₃CF₃^?, LL=dppe 3 a , dppy 3 b ; M=Cu, A=PF₆^?, LL=dppe 4 a , dppy 4 b ). The new compounds were characterized by different spectroscopic techniques and mass spectrometry The crystal structures of [Au₂(mes)₂(μ‐dppy)] ( 1 b ) and [Au₂Ag(μ‐mes)₂(μ‐dppe)][SO₃CF₃] ( 3 a ) were determined by a single‐crystal X‐ray diffraction study. 3 a in solid state is not a cyclic trinuclear Au₂Ag derivative but it gives an open polymeric structure instead, with the {Au₂(μ‐dppe)} fragments “linked” by {Ag(μ‐mes)₂} units. The very short distances of 2.7559(6) Å (Au? Ag) and 2.9229(8) Å (Au? Au) are indicative of gold–silver (metallophilic) and aurophilic interactions. A systematic study of their luminescence properties revealed that all compounds are brightly luminescent in solid state, at room temperature (RT) and at 77 K, or in frozen DMSO solutions with lifetimes in the microsecond range and probably due to the self‐aggregation of [Au₂M(μ‐mes)₂(μ‐LL)]⁺ units (M=Ag or Cu; LL=dppe or dppy) into an extended chain structure, through Au? Au and/or Au? M metallophilic interactions, as that observed for 3 a . In solid state the heterometallic Au₂M complexes with dppe ( 2 a – 4 a ) show a shift of emission maxima (from ca. 430 to the range of 520‐540 nm) as compared to the parent dinuclear organometallic product 1 a while the complexes with dppy ( 2 b–4 b ) display a more moderate shift (505 for 1 b to a max of 563 nm for 4 b ). More importantly, compound [Au₂Ag(μ‐mes)₂(μ‐dppy)]ClO₄ ( 2 b ) resulted luminescent in diluted DMSO solution at room temperature. Previously reported compound [Au₂Cl₂(μ‐LL)] (LL dppy 5 b ) was also studied for comparative purposes. The antimicrobial activity of 1–5 and Ag[A] (A=ClO₄^?, SO₃CF₃^?) against Gram‐positive and Gram‐negative bacteria and yeast was evaluated. Most tested compounds displayed moderate to high antibacterial activity while heteronuclear Au₂M derivatives with dppe ( 2 a – 4 a ) were the more active (minimum inhibitory concentration 10 to 1 μg mL^?1). Compounds containing silver were ten times more active to Gram‐negative bacteria than the parent dinuclear compound 1 a or silver salts. Au₂Ag compounds with dppy ( 2 b , 3 b ) were also potent against fungi.     

Competitive Intramolecular Aryl‐ and Alkyl‐C?H Bond Activation and Ligand Evaporation from Gaseous Bisimino Complexes [Pt(L)(CH3)((CH3)2S)]+ (L=C6H5NC(CH3)?C(CH3)NC6H5)

Mechanistic details for the formation of methane from the title compound as well as the combined elimination of (CH₃)₂S/CH₄ are derived from various mass‐spectrometric experiments including deuterium‐labeling studies and DFT calculations. For the first process, i.e., methane formation, we have identified three competing pathways in which the intact, Pt‐bonded methyl group combines with a H‐atom that originates from a phenyl substituent (ca. 7%), the dimethyl sulfide ligand (ca. 41%), and a methyl group of the diazabutadiene backbone (ca. 52%). In contrast, in the combined (CH₃)₂S/CH₄ elimination, the methane is specifically formed from the Pt‐bound CH₃ group and a H‐atom provided by one of the phenyl groups (‘cyclometalation’).     

Theoretical study of the electronic spectrum of binuclear gold(I) complexes

The electronic structure and the spectroscopic properties of [Au₂(CS₃)₂]^?2, [Au₂(pym‐2‐S)₂] (pym = pyrimidethiolate), [Au₂(dpm)₂]⁺² (dpm = bis(diphosphino)methane) were studied using density functional theory (DFT) at the B3LYP level. The absorption spectrum of these binuclear gold(I) complexes was calculated by single excitation time‐dependent (TD) method. All complexes showed a ¹(5dσ* → 6pσ) transition associated with a metal–metal charge transfer, which is strongly interrelated with the gold–gold distance. Furthermore, we have calculated the frequency of the gold–gold vibration (ν_Au2) on the above complexes. The values obtained are theoretically in agreement with experimental range. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

A novel mononuclear gold(I) complex: Synthesis and x-ray structure of [Au{P(C6H5)3}3][SiF5] · 1.5 CH2Cl2

Tris(triphenylphosphine)gold(I)-pentafluorosilicate(IV) ([Au{P(C₆H₅)₃}₃][SiF₅]) was prepared and the structure was determined by single crystal x-ray diffraction. The complex crystallizes in the triclinic space group P1 (No. 2). The lattice constants are a = 14.634(2) Å, b = 17.180(2) Å, c = 22.212(3) Å, α = 86.48(1)°, β = 78.95(1)°, γ = 83.99(1)°. Number of molecules per cell: Z = 4. The gold atoms are coordinated to three triphenylphosphine ligands to form the trigonal planar cation [Au{P(C₆H₅)₃}₃]⁺. Separated from the cation is the [SiF₅]^? anion which is regular trigonal bipyramidal coordinated. No interactions between the fluorine atoms and the gold atoms were observed.     

Au(II)化合物[Au(CH2)2PH2]2X2 (X＝F, Cl, Br, I)的量子化学理论研究

采用从头计算HF, MP2方法和密度泛函理论, 对Au(II)系列化合物[Au(CH₂)₂PH₂]₂X₂ (X＝F, Cl, Br, I)的几何结构、电子结构和振动频率进行了研究. 研究表明Au的5d和6s电子参与Au—Au以及Au—X之间的成键. Au—Au, Au—X键强烈的电子相关作用使HF方法不适于该体系的研究, BP86和B3LYP两种泛函给出较大的Au—Au和Au—X键长, 而MP2方法和局域的密度泛函方法则给出了合理的结构参数. 局域密度泛函方法计算得到的Au—Au键和 Au—X键振动频率也与实验数据符合较好. 还运用含时密度泛函理论计算了[Au(CH₂)₂PH₂]₂X₂的电子激发能, 对分子在紫外-可见光谱范围内的电子跃迁进行了分析, 考察了卤素配体对激发能的影响, 并结合分子轨道能级的变化对此给予了解释.     

103Rh-NMR-spektroskopischer Nachweis der gemischten Nonahalogenodirhodate(III), [Rh2ClnBr9–n]3−, n = 0–9

¹⁰³Rh NMR Spectroscopic Evidence of Mixed Nonahalogenodirhodates(III), [Rh₂Cl_nBr_9–n]^3?, n = 0–9 On heating a mixture of the tetrabutylammonium salts (TBA)₃[Rh₂Cl₉] and (TBA)₃[Rh₂Br₉] at 60°C in propylenecarbonate the complete system of the mixed nonahalogenodirhodates(III) [Rh₂Cl_nBr_9–n]^3?, n = 0–9 is formed. In the ¹⁰³Rh nmr spectra 40 different species have been detected, 16 with two equivalent ¹⁰³Rh atoms each resulting in one singlet and 24 with inequivalent ¹⁰³Rh atoms each pair giving two resonances. The signals of the geometric isomeres are not resolved. All 64 expected resonances are really observed. By additional measuring of the ¹⁰³Rh nmr spectra of the fractions n = 0–4 separable by ion exchange chromatography on DEAE cellulose, and utilizing characteristic increments of chemical shifts the complete and unambiguous assignment of all signals is achieved.     

Synthesis and molecular structure of biologically significant bis(1,3‐dimesityl‐4,5‐naphthoquinoimidazol‐2‐ylidene)gold(I) complexes with chloride and dichloridoaurate counter‐ions

Diffraction‐quality single crystals of two gold(I) complexes, namely bis(1,3‐dimesityl‐4,5‐naphthoquinoimidazol‐2‐ylidene)gold(I) chloride benzene monosolvate, [Au(C₂₉H₂₆N₂O₂)₂]Cl·C₆H₆ or [(NQMes)₂Au]Cl·C₆H₆, 2 , and bis(1,3‐dimesityl‐4,5‐naphthoquinoimidazol‐2‐ylidene)gold(I) dichloridoaurate(I) dichloromethane disolvate, [Au(C₂₉H₂₆N₂O₂)₂][AuCl₂]·2CH₂Cl₂ or [(NQMes)₂Au][AuCl₂]·2CH₂Cl₂, 4 , were isolated and studied with the aid of single‐crystal X‐ray diffraction analysis. Compound 2 crystallizes in a monoclinic space group C2/c with eight molecules in the unit cell, while compound 4 crystallizes in the triclinic space group P with two molecules in the unit cell. The crystal lattice of compound 2 reveals C—H…Cl^? interactions that are present throughout the entire structure representing head‐to‐tail contacts between the aromatic (C—H) hydrogens of naphthoquinone and Cl^? counter‐ions. Compound 4 stacks with the aid of short interactions between a naphthoquinone O atom of one molecule and the mesityl methyl group of another molecule along the a axis, leading to a one‐dimensional strand that is held together by strong π–η² interactions between the imidazolium backbone and the [AuCl₂]^? counter‐ion. The bond angles defined by the Au^I atom and two carbene C atoms [C(carbene)—Au—C(carbene)] in compounds 2 and 4 are nearly rectilinear, with an average value of ～174.1 [2]°. Though 2 and 4 share the same cation, they differ in their counter‐anion, which alters the crystal lattice of the two compounds. The knowledge gleaned from these studies is expected to be useful in understanding the molecular interactions of 2 and 4 under physiological conditions.     

Synthetic,Spectroscopic and Structural Studies of the Rhenium(I) Dicarbonyl Complexes of Phosphite,Phosphonite, and Phosphinite Ligands: cis,mer‐[ReBr(CO)2{PPh3‐n(OR)n}3] (R = Me,Et; n = 1—3)

The reaction of [ReBr(CO)₅] with phosphite and phosphonite ligands in toluene yielded cis, mer‐[ReBr(CO)₂L₃] ( 2 : L = P(OMe)₃ 2a : P(OEt)₃ 2b : PPh(OMe)₂ 2c : PPh(OEt)₂ 2d ). Compounds 2c and 2d were also obtained, as were the phosphinite complexes 2e [L = PPh₂(OMe)] and 2f [L = PPh₂(OEt)], by reaction of the corresponding phosphorus ligand with trans, mer‐[ReBr(CO)₃L₂]. Compounds 2 were all characterized by elemental analysis, mass spectrometry and NMR spectroscopy, and the structures of 2b , 2c and 2d were determined by X‐ray diffractometry. Compounds 2a‐d are stable in chloroform and dichloromethane, but 2e and 2f are transformed into the corresponding trans, mer‐[ReBr(CO)₃L₂] complexes by a reaction for which a partial mechanism is put forward.     

Synthese,NMR‐Spektren und Molekülstruktur von [(CH3)2Ga{μ‐P(H)Si(CH3)3}2Ga(CH3)2{μ‐P(Si(CH3)3)2}Ga(CH3)2]

Synthesis, NMR Spectra and Structure of [(CH₃)₂Ga{μ‐P(H)Si(CH₃)₃}₂Ga(CH₃)₂{μ‐P(Si(CH₃)₃)₂}Ga(CH₃)₂] The title compound has been prepared in good yield by the reaction of [Me₂GaOMe]₃ (Me = CH₃) with HP(SiMe₃)₂ in toluene (ratio 1 : 1,1) and purified by crystallization from pentane or toluene, respectively. This organogallium compound forms (Ga–P)₃ ring skeletons with one Ga–P(SiMe₃)₂–Ga and two Ga–P(H)SiMe₃–Ga bridges and crystallizes in the monoclinic space group C2/c. The known homologous Al‐compound is isotypic, both (M^III–P)₃ heterocycles have twist‐conformations, the ligands of the monophosphane bridges have trans arrangements.     

Synthesis,Structure and in vitro Antitumor Activity of a Multinuclear Diorganotin(IV) Complex [(n‐Bu)4Sn2{2,5‐F2C6H3C(O)NHO}2{2,5‐F2C6H3C(NO)O}]2

A new multinuclear dibutyltin(IV) complex [(n‐Bu)₄Sn₂{2,5‐F₂C₆H₃C(?O)NHO}₂{2,5‐F₂C₆H₃C(?NO)O}]₂ 1 , was synthesized and structurally characterized by melting point measurement, elemental analysis, FT‐IR, ¹H, ¹³C, ¹¹⁹Sn NMR spectroscopies, and X‐ray diffraction analysis. The complex exhibited in vitro antitumor activity against a murine sarcoma carcinoma cell line (S‐180), which was higher than that of 5‐fluorouracil (5‐Fu), currently used clinically as an antitumor agent.     

Stabilization of Substituted Triazenide Oxides: Synthesis and X‐ray Structural Features of Polymeric Potassium 3‐(4‐carboxylatophenyl)‐1‐methyltriazene N‐oxide‐hydrate, {K[O2C‐C6H4‐N(H)NN(CH3)O]·4H2O}n

3‐(4‐carboxyphenyl)‐1‐methyltriazene N‐oxide reacts with KOH in methanol/pyridine to give {K[O₂C‐C₆H₄‐N(H)NN(CH₃)O]·4H₂O}_n, Potassium‐3‐(4‐carboxylatophenyl)‐1‐methyltriazene N‐oxide). The terminal carboxylato group of the anion does not interact with the cation. In the crystal lattice of {K(C₈H₈N₃O₃)·4H₂O}_n each three of the four water molecules interact with two potassium cations, every K⁺ ion being the centre of six bridging K···O interactions. Potassium cations interact further with the terminal N‐oxigen atom of single [C₈H₈N₃O₃]^? anions achieving two parallel {C₈H₈N₃O₃^?K⁺}_n chains, which are linked through water molecules. The resulting polymeric, one‐dimensional chain, is operated by a screw axis 2₁ parallel to the crystallographic direction [010], along and equidistant to the K⁺ centres. The coordination of the K⁺ centres involves a distortion of the boat conformation of elementary sulfur (S₈) with the ideal C_2v symmetry.     

Palladium(II) Complexes with the Mixed‐Donor Ligand CH3S‐(CH2)3‐PPh2 Crystal Structures of [PdCl2{CH3S‐(CH2)3‐PPh2}n](n = 1, 2)

The phosphorus‐sulfur ligand 1‐(methylthio)‐3‐(diphenylphosphino)‐propane (S‐P3) has been synthesized and characterized by ¹H NMR and ¹³C NMR. Reactions of S‐P3 with [PdCl₂(PhCN)₂] afforded the complexes [PdCl₂(S‐P3)] ( I ) and [PdCl₂(S‐P3)₂] ( II ), in which S‐P3 acts as a bidentate and monodentate ligand, respectively. Compound I crystallizes in monoclinic space group P2₁/n (No. 14) with cell dimensions: a = 8.589(3), b = 15.051(3), c = 17.100(3)Å, β = 102.91(2)°, V = 2154.7(9)ų, Z = 4. Likewise, compound II crystallizes in monoclinic space group P2₁/n (No. 14) with a = 9.993(5), b = 8.613(4), c = 18.721(5)Å, β = 90.18(3)°, V = 1611.3(12)ų, Z = 2. Compound II has a trans square planar configuration with only the P‐site of the ligand bonded to the palladium atom.     

Ten‐vertex rhodadithiaborane ­chemistry: [8‐{I(CH2)5}‐3‐(η5‐C5Me5)‐arachno‐3,7,8‐RhS2B8H9]

Neutral 8‐(5‐iodo‐n‐pentyl)‐3‐(η⁵‐penta­methyl­cyclo­pentadi­enyl)‐arachno‐3‐rhoda‐7,8‐di­thia­undecaborane, [Rh(C₅H₁₉B₈­IS₂)­(C₁₀H₁₅)], obtained from the [arachno‐7,8‐S₂B₉H₁₀]^? anion by treatment with I(CH₂)₅I followed by [Rh(C₅Me₅)Cl₂]₂ and N,N,N′,N′‐tetra­methyl‐1,8‐di­amino­naphthalene, has the 11‐vertex cluster geometry of [arachno‐7,8‐S₂B₉H₁₀]^?, but with an {Rh(C₅Me₅)} unit in the 3‐position instead of a {BH} unit, and with a –(CH₂)₅I chain attached exo to an S atom.     

Über die Darstellung der N-Chlor-N-Methylammoniumsalze (CH3)nNCl4–n+MF6− (n = 1–3; M = As,Sb) und (CH3)2NCIX+MF6− (X = F,Br)

About the Preparation of N-Chloro-N-Methylammonium Salts (CH₃)_nNCl_4–n⁺MF₆^? (n = 1–3; M = As, Sb) and (CH₃)₂NClX⁺MF₆^? (X = F, Br) Simple one-step methods for the preparation of the methylated chloroammonium salts (CH₃)_nNCl_4–n⁺MF₆^? (n = 1–3; M = As, Sb) and for (CH₃)₂NClX⁺MF₆^? (X = F, Br) are reported. Their vibrational and NMR-spectroscopical data are discussed in comparison.     

Formation and structure of diruthenium complexes Ru2(CO)6−n (PPh3) n {μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} (n=1, 2)

Ruthenium carbonyl triphenylphosphine complexes Ru₂(CO)_6−n (PPh₃) _n {μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} (n=1, 2) were obtained by the reaction of complex Ru₂(CO)₆{μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} containing the ruthenacyclopentadiene moiety with PPh₃ in refluxing toluene. The complexes were characterized by IR and by¹H,¹³C, and³¹P NMR spectroscopy, and by X-ray analysis. The monophosphine derivative is identical to the complex formed by fragmentation of the Ru₃(CO)₈(PPh₃){μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} cluster and contains the PPh₃ ligand at the ruthenium atom of the ruthenacyclopentadiene moiety. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1836–1843, September, 1998