Highly luminescent gold(I)-silver(I) and gold(I)-copper(I) chalcogenide clusters

The reactions of [AuClL] with Ag(2)O, where L represents the heterofunctional ligands PPh(2)py and PPh(2)CH(2)CH(2)py, give the trigoldoxonium complexes [O(AuL)(3)]BF(4). Treatment of these compounds with thio- or selenourea affords the triply bridging sulfide or selenide derivatives [E(AuL)(3)]BF(4) (E=S, Se). These trinuclear species react with Ag(OTf) or [Cu(NCMe)(4)]PF(6) to give different results, depending on the phosphine and the metal. The reactions of [E(AuPPh(2)py)(3)]BF(4) with silver or copper salts give [E(AuPPh(2)py)(3)M](2+) (E=O, S, Se; M=Ag, Cu) clusters that are highly luminescent. The silver complexes consist of tetrahedral Au(3)Ag clusters further bonded to another unit through aurophilic interactions, whereas in the copper species two coordination isomers with different metallophilic interactions were found. The first is analogous to the silver complexes and in the second, two [S(AuPPh(2)py)(3)](+) units bridge two copper atoms through one pyridine group in each unit. The reactions of [E(AuPPh(2)CH(2)CH(2)py)(3)]BF(4) with silver and copper salts give complexes with [E(AuPPh(2)CH(2)CH(2)py)(3)M](2+) stoichiometry (E=O, S, Se; M=Ag, Cu) with the metal bonded to the three nitrogen atoms in the absence of AuM interactions. The luminescence of these clusters has been studied by varying the chalcogenide, the heterofunctional ligand, and the metal.     

Aluminum(I) and Gallium(I) Compounds: Syntheses,Structures, and Reactions

By the end of the last century there were already the first indications of the possible existence of Al¹ halides. However, it was only through the pioneering works of W. Klemm, who would have celebrated his 100th birthday on January 6, 1996, that detailed spectroscopic investigations became possible. Since the end of the 1970s the reactivity of AlX and GaX species in solid noble gases has been confirmed by numerous examples. In recent years formally monovalent Al and Ga species have been successfully synthesized on a preparative scale. In addition to the first halides, organometallic compounds with metal–metal bonds have been isolated and investigated with regard to their chemical properties. The fundamental importance of such species has been documented in this journal among others in the form of two highlight articles in which experimental and theoretical aspects have been examined with examples, and parallels and differences with respect to boron chemistry have been illustrated. This review is intended to give an account of the chronological development of this research area over the last few years, but an attempt is also made to categorize the experimental results achieved not only with respect to structure, thermodynamics, and reactivity, but also with the aid of quantum chemical calculations and by comparative considerations.     

Structural Diversity of Calcium Organocuprates(I): Synthesis of Mesityl Cuprates via Addition and Transmetalation Reactions of Mesityl Copper(I)

The addition of [(L)₄Ca(I)Mes] (Lewis base L=thf, Et₂O) to mesityl copper(I) and the transmetalation reaction of mesityl copper(I) with activated calcium are suitable pathways for the synthesis of dimesityl cuprates(I) of calcium. However, the structures of the calcium cuprates(I) depend on the preparative procedure. The transmetalation reaction leads to the formation of [Mes‐Cu‐Mes]^? anions whereas the addition yields dinuclear [(Mes‐Cu)₂(μ‐Mes)]^? anions. The solvent‐separated counterions are [Ca(thf)₆]²⁺ and [(thf)₅CaI]⁺, respectively. In contrast to these findings, the addition of [(L)₄Ca(I)Mes] to mesityl copper(I) in an Et₂O/toluene mixture led to formation of tetrameric solvent‐free iodocalcium dimesityl cuprate(I) [ICa(μ‐η¹,η⁶‐Mes₂Cu)]₄, representing a rare example of a heavy Normant‐type organocuprate.     

Darstellung und Eigenschaften der Phthalocyaninato(2–)metallate(I) von Cobalt,Rhodium und Iridium; Kristallstruktur von Tetra(n-butyl)ammoniumphthalocyaninato(2–)cobaltat(I)-Aceton-Solvat

Syntheses and Properties of Phthalocyaninato(2–)metallates(I) of Cobalt, Rhodium, and Iridium; Crystal Structure of Tetra(n-butyl)ammonium Phthalocyaninato(2–)cobaltate(I) Acetone Solvate Cobaltphthalocyaninate(2–) reacts with tetra(n-butyl)ammonium boranate in acetone yielding soluble tetra(n-butyl)ammonium phthalocyaninato(2–)cobaltate(I). The green platelets of its acetone solvate crystallize in the monoclinic space group P1 2₁/c (no. 14) with cell parameters: a = 12.370(1) Å, b = 23.370(3) Å, c = 15.952(8) Å, β = 93.55(2)°, Z = 4. The Co atom is located in the centre of the distorted phthalocyaninate (waving distortion). The average Co–N_iso distance is 1.894 Å. Dichlorophthalocyaninato(2–)metal(III) acid of rhodium and iridium reacts in boiling sodium isopropylate/isopropanol with tetra(n-butyl)ammonium boranate yielding violet tetra(n-butyl)ammonium phthalocyaninato(2–)rhodate(I) and -iridate(I). The UV-VIS-NIR spectra show normal π–π* transitions of the pc^2– ligand which are shifted in the series Co < Rh < Ir to higher energy. Absorbances (in 10³ cm^–1) at 18.2/19.4/21.4/23.6 (Co), 22.0/22.8/40.4 (Rh) and 25.6 (Ir) are assigned to M → pc^2– charge transfer transitions. The vibrational spectra are typical for the pc^2– ligand. The very low absorbance of the IR bands at 916/1067/1330 cm^–1 is diagnostic for low-valent metal phthalocyaninates.     

Fluorocyclisation of Oximes to Isoxazolines Through I(I)/I(III) Catalysis

A regioselective fluorocyclisation of β,γ-unsaturated oximes through I(I)/I(III) catalysis is disclosed to generate 5-fluoromethylated isoxazolines. The transformation leverages p-iodotoluene as an inexpensive catalyst, Selectfluor® as the terminal oxidant and an amine⋅HF complex (1 : 7.5) as both the fluoride and Brønsted acid source. The λ³-iodane p-TolIF₂, which is generated in situ, engages the pendant alkene of the substrate to facilitate a cyclisation/fluorination sequence. A range of 5-fluoromethyl isoxazolines can be generated using this method, including aliphatic and aromatic systems (up to 56 % yield). Single crystal X-ray analysis of a representative example reveals a conformation that is consistent with the stereoelectronic gauche effect between the exocyclic C(sp³)−F bond and the C(sp³)−O of the isoxazoline (ϕ_OCCF=−62.0°).     

Zwei- und dreikernige Komplexe des WS42– mit Tricarbonylrhenium(I)- und -mangan(I)-Fragmenten: Struktur,Spektroskopie und Elektrochemie

Di- and Trinuclear Complexes of WS₄^2– with Tricarbonylrhenium(I) and -manganese(I) Fragments: Structure, Spectroscopy, and Electrochemistry The reaction of (NEt₄)₂WS₄ with two equivalents of M(CO)₅(O₃SCF₃), M = Mn or Re, in acetonitrile yielded the crystallographically characterized neutral compounds [(CH₃CN)(OC)₃M(μ-S₂WS₂)M(CO)₃(NCCH₃)]. The individual molecules are chiral and contain WS₄ and MS₂(CO)₃(CH₃CN) moieties in approximately tetrahedral and octahedral configurations, respectively. Vibrational and electronic absorption spectra are in agreement with the crystal structure, comparable results were obtained for trinuclear complexes [(L)(OC)₃Re(μ-S₂WS₂)Re(CO)₃(L)](NEt₄)₂, L = Cl^– or CN^–, and for the dinuclear systems [(WS₄)Re(CO)₃(CH₃CN)](NEt₄) and [(WS₄)Re(CO)₃Cl](NEt₄)₂. Electrochemical processes are irreversible due to the lability of acetonitrile or chloride ligands in corresponding complexes, however, the cyanide compound [(NC)(OC)₃Re(μ-S₂WS₂)Re(CO)₃(CN)]^2– showed reversible one-electron reduction to a first tetrathiotungstate(V) species as detected by UV/Vis/IR spectroelectrochemistry.     

Synthesis and Reactivity Studies of Amido-Substituted Germanium(I)/Tin(I) Dimers and Clusters

Three amide ligands of varying steric bulk and electronic properties were utilized to prepare a series of amido-germanium(II)/tin(II) halide compounds, (LEX)_n, (L= -N{B(DipNCH)₂}(SiMe₃), ^TBoL; -N{B(DipNCH)₂}(SiPh₃), ^PhBoL; -N(Dip)(tBu), ^DBuL; Dip=C₆H₃iPr₂-2,6; E=Ge or Sn; X=Cl or Br; n=1 or 2). Reductions of these with a magnesium(I) dimer, {(^MesNacnac)Mg}₂ (^MesNacnac=[(MesNCMe)₂CH]⁻, Mes=mesityl), afforded singly bonded amido-digermynes (^TBoLGe−Ge^TBoL and ^PhBoLGe−Ge^PhBoL), and an amido-distannyne (^PhBoLSn−Sn^PhBoL), in addition to several low-valent, amido stabilized tetrel–tetrel bonded cluster compounds, (^DBuLGe)₄, (^DBuLSn)₆ and Sn₅(^TBoL)₄. The nature of the products resulting from these reactions was largely dependent on the steric bulk of the amide ligand employed. Cluster (^DBuLGe)₄ possessed an unusual folded butterfly structure, the bonding and electronic of which were examined using DFT calculations. Reactions of the amido-germanium(I) compounds with H₂ were explored, and gave rise to the amido-digermene, ^TBoL(H)Ge=Ge(H)^TBoL and the cyclotetragermane, {^DBuL(H)Ge}₄. Reactions of (^DBuLGe)₄ with a series of unsaturated small molecule substrates yielded ^DBuLGeOGe^DBuL, ^DBuLGe(μ-C₂H₄)₂Ge^DBuL and ^DBuLGe(μ-1,4-C₆H₈)(μ-1,2-C₆H₈)Ge^DBuL. The latter results imply that (^DBuLGe)₄ can act as a masked source of the digermyne ^DBuLGeGe^DBuL in these reactions. All further reactivity studies indicated that the germanium(I) compounds exhibit a “transition-metal-like” behavior, which is closely related to that previously described for bulky digermynes and related compounds.     

Homoleptic Phosphaalkyne Complexes of Silver(I)

By employing silver salts with a weakly coordinating anion Ag[A] ([A]=[FAl{OC₁₂F₁₅}₃], [Al{OC(CF₃)₃}₄]), two phosphaalkynes could be coordinated side‐on to a bare silver(I) center to form the unprecedented homoleptic complexes [Ag(η²‐P≡CtBu)₂][FAl{OC₁₂F₁₅}₃] ( 1 ) and [Ag(η²‐P≡CtBu)₂][Al{OC(CF₃)₃}₄] ( 2 ). DFT calculations show that the perpendicular arrangement in 1 is the minimum energy structure of the coordination of the two phosphaalkynes to a silver atom, whereas for 2 a unique square‐planar coordination mode of the phosphaalkynes at Ag⁺ was found. Reactions with donor molecules yield the trigonally planar coordinated silver salts [((CH₃)₂CO)Ag(η²‐P≡CtBu)₂][FAl{OC₁₂F₁₅}₃] ( 3 ) and [(C₇H₈)₂Ag(η²‐P≡CtBu)][FAl{OC₁₂F₁₅}₃] ( 4 ). All of the compounds were comprehensively characterized in solution and in the solid state.     

Gold(I) and Gold(III) Trifluoromethyl Derivatives

Trifluoromethylation of AuCl₃ by using the Me₃SiCF₃/CsF system in THF and in the presence of [PPh₄]Br proceeds with partial reduction, yielding a mixture of [PPh₄][Au^I(CF₃)₂] ( 1′ ) and [PPh₄][Au^III(CF₃)₄] ( 2′ ) that can be adequately separated. An efficient method for the high‐yield synthesis of 1′ is also described. The molecular geometries of the homoleptic anions [Au^I(CF₃)₂]^? and [Au^III(CF₃)₄]^? in their salts 1′ and [NBu₄][Au^III(CF₃)₄] ( 2 ) have been established by X‐ray diffraction methods. Compound 1′ oxidatively adds halogens, X₂, furnishing [PPh₄][Au^III(CF₃)₂X₂] (X=Cl ( 3 ), Br ( 4 ), I ( 5 )), which are assigned a trans stereochemistry. Attempts to activate C? F bonds in the gold(III) derivative 2′ by reaction with Lewis acids under different conditions either failed or only gave complex mixtures. On the other hand, treatment of the gold(I) derivative 1′ with BF₃?OEt₂ under mild conditions cleanly afforded the carbonyl derivative [Au^I(CF₃)(CO)] ( 6 ), which can be isolated as an extremely moisture‐sensitive light yellow crystalline solid. In the solid state, each linear F₃C‐Au‐CO molecule weakly interacts with three symmetry‐related neighbors yielding an extended 3D network of aurophilic interactions (Au???Au=345.9(1) pm). The high $\tilde \nu $ _CO value (2194 cm^?1 in the solid state and 2180 cm^?1 in CH₂Cl₂ solution) denotes that CO is acting as a mainly σ‐donor ligand and confirms the role of the CF₃ group as an electron‐withdrawing ligand in organometallic chemistry. Compound 6 can be considered as a convenient synthon of the “Au^I(CF₃)” fragment, as it reacts with a number of neutral ligands L, giving rise to the corresponding [Au^I(CF₃)(L)] compounds (L=CNtBu ( 7 ), NCMe ( 8 ), py ( 9 ), tht ( 10 )).     

Zur Struktur zweier Isothiazolium‐Polyiodide (C19H16FeNS)I5 und (C15H12NS)2I8

On the Structure of Two Isothiazolium Polyiodides (C₁₉H₁₆FeNS)I₅ and (C₁₅H₁₂NS)₂I₈ By oxidation of 3‐phenylamino thiopropenones with iodine two isothiazolium polyiodides were obtained, whose structures have been determined by X‐ray structure analysis. 2‐Phenyl‐5‐ferrocenyl‐isothiazolium pentaiodide(C₁₉H₁₆FeNS)I₅ forms a layer structure with isothiazolium cations and polyiodide anions. The polyiodide layers contain pentaiodide ions I₅^–, triiodide ions I₃^– and iodine molecules I₂. Bis(2,5‐diphenyl‐isothiazolium) octaiodide (C₁₅H₁₂NS)₂I₈ also forms a layer structure with isothiazolium cations and polyiodide anions. The polyiodide layers are built up by octaiodide ions I₈^2–, pentaiodide ions I₅^– and triiodide ions I₃^–.     

Bulky Cations and Four different Polyiodide Anions in [Lu(Db18c6)(H2O)3(thf)6]4(I3)2(I5)6(I8)(I12)

Black single crystals of [Lu(Db18c6)(H₂O)₃(thf)₆]₄(I₃)₂(I₅)₆(I₈)(I₁₂) were obtained from lutetium, I₂ and Db18c6 (dibenzo‐18‐crown‐6) in THF solution. In the bulky cation, Lu³⁺ is surrounded by nine oxygen atoms, six of Db18c6 and three of water molecules to which two THF molecules are attached each. Meanwhile, four polyiodide anions, (I₃)^–, (I₅)^–, (I₈)^2– and (I₁₂)^2–, in a 2:6:1:1 ratio form a three‐dimensional network and leave space for the bulky cations.     

Diverse Reactivity of a Ca(I) Synthon

Low-valent Mg^I complexes like (BDI)Mg−Mg(BDI) have found wide-spread application as specialty reducing agents (BDI=β-diketiminate). Also their redox reactivity was extensively investigated. In contrast, attempts to isolate similar Ca^I complexes led to reduction of the aromatic solvents or N₂. Complex (^DIPePBDI)Ca(μ₆,μ₆-C₆H₆)Ca(^DIPePBDI) ( VIII ) should be regarded a Ca^II complex with a bridging C₆H₆²⁻ dianion (^DIPePBDI=HC[C(Me)N-DIPeP]₂, DIPeP=2,6-C(H)Et₂-phenyl). It can react as a Ca^I synthon by releasing benzene and two electrons. Herein we describe the reactivity of VIII with benzene, biphenyl, naphthalene, anthracene, COT, Ph₃SiCl, PhSiH₃, a (BDI)AlI₂ complex, H₂, PhX (X=F, Cl, Br, I), tBuOH and tBuCH₂I. The C₆H₆²⁻ dianion in VIII can react as a 2e⁻ source, a nucleophile or a Brønsted base. In some cases radical reactivity cannot be excluded. Crystal structures of (^DIPePBDI)Ca(μ₈,μ₈-COT)Ca(^DIPePBDI) ( 1 ) and [(^DIPePBDI)CaX ⋅ (THF)]₂ (X=F, Cl, Br, I) ( 2 – 5 ) are described.     

Hypercoordinated compounds of gold(I)

Mono- and binuclear gold(I) derivatives ofortho-substituted diphenyl ether, C₆H₅OC₆H₄AuPPh₃ and O(C₆H₄)₂(AuPPh₃)₂, were prepared by the reaction of the 2,2'-dilithium derivative of diphenyl ether with ClAuPPh₃. X-Ray structural study has shown that these compounds contain secondary intramolecular bonds between the gold and oxygen atoms. The interaction of C₆H₅OC₆H₄AuPPh₃ with (AuPPh₃)BF₄ affords the [C₆H₅OC₆H₄(AuPPh₃)₂]BF₄ cationic complex. The latter reacts with PPh₃ to give the starting C₆H₅OC₆H₄AuPPh₃ complex.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 729–736, April, 1994.The authors wish to thank A. L. Blyumenfel'd for recording³¹P NMR spectra, D. V. Zagorevskii and K. V. Kazakov who obtained mass spectra, and Yu.L. Slovokhotov who carried out the EXSAFS study.The study described in the present paper was partly supported by the International Scientific Fund, grant N Ch. 002479.     

Quecksilberverbindungen mit Cyancarbanionen. I. Synthese und Kristallstruktur von Diquecksilber(I)-bis(tricyanmethanid)

Mercury Compounds with Cyancarbanions. I . Synthesis and Crystal Structure of Dimercury(I)-bis(tricyanmethanide ) With the triclinic unit cell, space group P1 , with the lattice constants a = 5.2794(1) Å, b = 9.9279(1) Å, c = 11.3376(2) Å, α = 71.004(4)°, β = 76.459(2)° and γ = 74.601(4)° are two formula units. The three-dimensional network, which characterizes the structure, results from dimercury(I) ions with sp³ hybridization, which form beside the homonuclear metal bonding three covalent bonds to cyanonitrogen atoms. The tricyanmethanide ion acts by losing symmetry as a tridentate ligand.     

Highly luminescent octanuclear Au(I)-Cu(I) clusters adopting two structural motifs: the effect of aliphatic alkynyl ligands

Reactions of the homoleptic (AuC(2)R)(n) precursors with stoichiometric amount of diphosphine ligand PPh(2)C(6)H(4)PPh(2) (P^P) and Cu(+) ions lead to an assembly of a new family of bimetallic clusters [Au(6)Cu(2)(C(2)R)(6)(P^P)(2)](2+) (type I; R=9-fluorenolyl (1), diphenylmethanolyl (2), 2,6-dimethyl-4-heptanolyl (3), 1-cyclohexanolyl (4), Cy (5), tBu (6)). In the case of R=1-cyclohexanolyl, a structurally different complex [Au(6)Cu(2)(C(2)C(6)H(11)O)(6)(P^P)(3)](2+) (7, type II) could be obtained by treatment of 4 with one equivalent of the diphosphine, while for R=isopropanolyl only the latter type of cluster [Au(6)Cu(2)(C(2)C(3)H(7)O)(6)(P^P)(3)](2+) (8) was detected. Steric bulkiness of the alkynyl ligands and O···H-O hydrogen bonding are suggested to play an important role in stabilizing the type I and type II cluster structural motif, respectively. All the complexes exhibit intense photoluminescence in solution with emission parameters that depending on the geometrical arrangement of the octanuclear metal core. The clusters 1-4 and 6 show single emission band in a blue region (469-488 nm) with maximum quantum yield of 94% (4), while structurally different 7 and 8 emit yellow-orange (590 nm) with unity quantum efficiency. The theoretical DFT calculations of the electronic structures have been carried out to demonstrate that the metal-centered triplet emission within the heterometallic core plays a key role for the observed phosphorescence.