Komplexe der Alkalimetalltetraphenylborate mit makrocyclischen Kronenethern

Complexes of the Alkali Metal Tetraphenylborates with Macrocyclic Crown Ethers Alkali metal tetraphenylborates, MB(C₆H₅)₄ (M = Li to Cs), react in tetrahydrofuran with macrocyclic crown ethers to give complexes of the general formula MB(C₆H₅)₄(crown)_m(THF)_n. Suitable single crystals for X‐ray structure analysis were grown from a solvent mixture of tetrahydrofuran and n‐hexane. The salt like complexes [Li(12‐crown‐4)(thf)][B(C₆H₅)₄] ( 1 ), [Na(15‐crown‐5)(thf)][B(C₆H₅)₄] ( 2 ), and [Cs(18‐crown‐6)₂][B(C₆H₅)₄] · THF ( 6 ), the mononuclear molecular complexes [KB(C₆H₅)₄(18‐crown‐6)(thf)] ( 3 ), [RbB(C₆H₅)₄(18‐crown‐6)] ( 4 ), and [CsB(C₆H₅)₄(18‐crown‐6)] · THF ( 5 ), and the compound [CsB(C₆H₅)₄(18‐crown‐6)]₂[Cs(18‐crown‐6)₂][B(C₆H₅)₄] ( 7 ), which contains a binuclear molecule ([CsB(C₆H₅)₄(18‐crown‐6)]₂) beside a [Cs(18‐crown‐6)₂]⁺ cation and a [B(C₆H₅)₄]^? anion, are described. All compounds are charactarized by infrared spectra, elemental analysis, NMR‐spectroscopy, and X‐ray single crystal structure analysis.     

Crystalline Diuranium Phosphinidiide and μ‐Phosphido Complexes with Symmetric and Asymmetric UPU Cores

Reaction of [U(Tren^TIPS)(PH₂)] ( 1 , Tren^TIPS=N(CH₂CH₂NSiPrⁱ₃)₃) with C₆H₅CH₂K and [U(Tren^TIPS)(THF)][BPh₄] ( 2 ) afforded a rare diuranium parent phosphinidiide complex [{U(Tren^TIPS)}₂(μ‐PH)] ( 3 ). Treatment of 3 with C₆H₅CH₂K and two equivalents of benzo‐15‐crown‐5 ether (B15C5) gave the diuranium μ‐phosphido complex [{U(Tren^TIPS)}₂(μ‐P)][K(B15C5)₂] ( 4 ). Alternatively, reaction of [U(Tren^TIPS)(PH)][Na(12C4)₂] ( 5 , 12C4=12‐crown‐4 ether) with [U{N(CH₂CH₂NSiMe₂Bu^t)₂CH₂CH₂NSi(Me)(CH₂)(Bu^t)}] ( 6 ) produced the diuranium μ‐phosphido complex [{U(Tren^TIPS)}(μ‐P){U(Tren^DMBS)}][Na(12C4)₂] [ 7 , Tren^DMBS=N(CH₂CH₂NSiMe₂Bu^t)₃]. Compounds 4 and 7 are unprecedented examples of uranium phosphido complexes outside of matrix isolation studies, and they rapidly decompose in solution underscoring the paucity of uranium phosphido complexes. Interestingly, 4 and 7 feature symmetric and asymmetric UPU cores, respectively, reflecting their differing steric profiles.     

Triamidoamine–Uranium(IV)‐Stabilized Terminal Parent Phosphide and Phosphinidene Complexes

Reaction of [U(Tren^TIPS)(THF)][BPh₄] ( 1 ; Tren^TIPS=N{CH₂CH₂NSi(iPr)₃}₃) with NaPH₂ afforded the novel f‐block terminal parent phosphide complex [U(Tren^TIPS)(PH₂)] ( 2 ; U–P=2.883(2) Å). Treatment of 2 with one equivalent of KCH₂C₆H₅ and two equivalents of benzo‐15‐crown‐5 ether (B15C5) afforded the unprecedented metal‐stabilized terminal parent phosphinidene complex [U(Tren^TIPS)(PH)][K(B15C5)₂] ( 4 ; U?P=2.613(2) Å). DFT calculations reveal a polarized‐covalent U?P bond with a Mayer bond order of 1.92.     

苯并15冠5与钼多酸的组装

以苯并15冠5和钼多酸为原料, 用水热法合成了两个新颖的超分子配合物[Na(B30C10)][Mo₆O₁₉] (1)和[NaL(CH₃CN)][NaL][α-PMo₁₂O₄₀][NaL₂] (L＝B15C5) (2), 并用单晶X射线衍射测定了它们的晶体结构. 配合物1属单斜晶系, 空间群为C2/m, 它包含三个基本单元: Na^＋, B15C5和Mo₆O , 冠醚分子和Na^＋配位, 并通过静电作用力和多酸分子相连. 配合物2属三斜晶系, 空间群为P-1, 它包含一个[α-PMo₁₂O₄₀]^3－离子和三个钠离子配合物. [Na(B15C5)]^＋通过Mo-O-Na-O键和多酸阴离子相连.     

The Arene‐Stabilized η5‐Pentamethylcyclopentadienyl Arsenic Dication [(η5‐Cp*)As(toluene)]2+

Double chloride abstraction of Cp*AsCl₂ gives the dicationic arsenic species [(η⁵‐Cp*)As(tol)][B(C₆F₅)₄]₂ ( 2 ) (tol=toluene). This species is shown to exhibit Lewis super acidity by the Gutmann–Beckett test and by fluoride abstraction from [NBu₄][SbF₆]. Species 2 participates in the FLP activation of THF affording [(η²‐Cp*)AsO(CH₂)₄(THF)][B(C₆F₅)₄]₂ ( 5 ). The reaction of 2 with PMe₃ or dppe generates [(Me₃P)₂As][B(C₆F₅)₄] ( 6 ) and [(σ‐Cp*)PMe₃][B(C₆F₅)₄] ( 7 ), or [(dppe)As][B(C₆F₅)₄] ( 8 ) and [(dppe)(σ‐Cp*)₂][B(C₆F₅)₄]₂ ( 9 ), respectively, through a facile cleavage of C?As bonds, thus showcasing unusual reactivity of this unique As‐containing compound.     

Synthesis and Characterization of the 1 : 1-Adducts of In(C6F5)3 with Acetonitrile,Glyme, and DMAP (DMAP = 4-(N,N-dimethylamino)pyridine), and [PNP][In(C6F5)4] (PNP = bis(triphenylphosphinanyliden)immonium) – the Crystal Structure of [PNP][In(C6F5)4]

In(C₆F₅)₃ · CH₃CN and In(C₆F₅)₃ · glyme were synthesized from InCl₃ and Cd(C₆F₅)₂ in CH₃CN or glyme in 43% and 35% yield, respectively. Replacement of CH₃CN or (C₂H₅)₂O by DMAP yielded the corresponding 1 : 1-adduct. [PNP][In(C₆F₅)₄] was best prepared from the corresponding cesium salt which was best synthesized from the reaction of stoichiometric amounts of In(C₆F₅)₃ · CH₃CN, (CH₃)₃ SiC₆F₅ and CsF in good yield. [PNP][In(C₆F₅)₄] crystallizes in the triclinic space group P 1, a = 1104.9(4) pm, b = 1442.4(6) pm, c = 1833.8(8) pm, α = 110.87(2)°, β = 92.04(3)°, γ = 96.55(3)°, Z = 2.     

Titanium(IV) Cations with Trigonal Monopyramidal Geometry: Unusual Lewis Acids Supported by a Triaryl Triamidoamine Ligand

Protonolysis of the titanium alkyl complex [Ti(CH₂SiMe₃)(Xy-N₃N)] (Xy-N₃N=[{(3,5-Me₂C₆H₃)NCH₂CH₂}₃N]³⁻) supported by a triamidoamine ligand, with [NEt₃H][B(3,5-Cl₂C₆H₃)₄] or [PhNMe₂H][B(C₆F₅)₄] afforded the cations [Ti(Xy-N₃N)][A] (A⁻=[B(3,5-Cl₂C₆H₃)₄]⁻ ( 1[B(Ar^Cl)₄] ; B(Ar^Cl)₄=tetrakis(3,5-dichlorophenyl)borate); A⁻=[B(C₆F₅)₄]⁻ ( 1[B(Ar^F)₄] ; B(Ar^F)₄=tetrakis[3,5-bis(trifluoromethyl)phenyl]borate). These Lewis acidic cations were reacted with coordinating solvents to afford the cations [Ti(L)(Xy-N₃N)][B(C₆F₅)₄] ( 2-L ; L=Et₂O, pyridine and THF). XRD analysis revealed a trigonal monopyramidal (TMP) geometry for the tetracoordinate cations in 1[B(Ar^X)₄] and trigonal bipyramidal (TBP) geometry for the pentacoordinate cations in 2-L . Variable-temperature NMR spectroscopy showed a dynamic equilibrium for 2-Et₂O in solution, involving the dissociation of Et₂O. Coordination to the titanium(IV) center activated the THF molecule, which, in the presence of NEt₃, underwent ring-opening to give the titanium alkoxide [Ti(O(CH₂)₄NEt₃)(Xy-N₃N)][B(3,5-Cl₂C₆H₃)₄] ( 3 ). Hydride abstraction from C_β,eq of the triamidoamine ligand arm in [Ti(CH₂SiMe₃)(Xy-N₃N)] or [Ti(NMe₂)(Xy-N₃N)] with [Ph₃C][B(3,5-Cl₂C₆H₃)₄] led to the diamidoamine–imine complex [Ti(R){(Xy-N=CHCH₂)(Xy-NCH₂CH₂)₂N}][B(3,5-Cl₂C₆H₃)₄] (R=CH₂SiMe₃ ( 4 a ); R=NMe₂ ( 4 b )). Hydride addition to 4 b with [Li(THF)][HBPh₃] gave [Ti(NMe₂)(Xy-N₃N)], whereas KH deprotonated further to give [Ti(NMe₂){(Xy-NCH=CH)(Xy-NCH₂CH₂)₂N}] ( 5 ). XRD on single crystals of 3 and 4 b confirmed the proposed structures.     

Latent cationic palladium(II) phosphine carboxylate complexes for norbornene polymerization

The catalytic efficacy of trans‐[(R₃P)₂Pd(O₂CR′)(LB)][B(C₆F₅)₄] ( 1 ) (LB = Lewis base) and [(R₃P)₂Pd(κ²‐O,O‐O₂CR′)][B(C₆F₅)₄] ( 2 ) for mass polymerization of 5‐n‐butyl‐2‐norbornene (Butyl‐NB) was investigated. The nature of PR₃ and LB in 1 and 2 are the most critical components influencing catalytic activity/latency for the mass polymerization of Butyl‐NB. Further, it was shown that 1 is in general more latent than 2 in mass polymerization of Butyl‐NB. 5‐n‐Decyl‐2‐norbornene (Decyl‐NB) was subjected to solution polymerization in toluene at 63(±3) °C in the presence of several of the aforementioned palladium complexes as catalysts and the polymers obtained were characterized by gel permeation chromatography. Cationic trans‐[(R₃P)₂PdMe(MeCN)][B(C₆F₅)₄] [R = Cy ( 3a ), and ⁱPr ( 3b )] and trans‐[(R₃P)₂PdH (MeCN)][B(C₆F₅)₄] [R = Cy ( 4a ), and ⁱPr ( 4b )], possible products from thermolysis of trans‐[(R₃P)₂Pd(O₂CMe)(MeCN)][B(C₆F₅)₄] [R = Cy ( 1a ) and ⁱPr ( 1g )], as well as trans‐[(R₃P)₂Pd(η³‐C₃H₅)][B(C₆F₅)₄] [R = Cy ( 5a ), and ⁱPr ( 5b )], were also examined as catalysts for solution polymerization of Decyl‐NB. A maximum activity of 5360 kg/(molPd h) of 2a was achieved at a Decyl‐NB/Pd: 26,700 ratio which is slightly better than that achieved with 5a [activity: 5030 kg/(molPd h)] but far less compared with 4a [activity: 6110 kg/(molPd h)]. Polydispersity values indicate a single highly homogeneous character of the active catalyst species. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 103–110, 2009     

Acyl‐Phosphide Anions via an Intermediate with Carbene Character: Reactions of K[PtBu2] and CO

The analogy of the reactivity of group 1 phosphides to that of FLPs is further demonstrated by reactions with CO, affording a new synthetic route to acyl‐phosphide anions. The reaction of [K(18‐crown‐6)][PtBu₂] ( 1 ) with CO affords [(18‐crown‐6)K?THF₂][Z‐tBuP=C(tBu)O] ( 2?THF₂ ) as the major product, and the minor product [K₆(18‐crown‐6)][(tBu₂PCO)₂]₃ ( 3 ). Species 2 reacts with either BPh₃ or additional CO to give [K(18‐crown‐6)][(Ph₃B)tBuPC(tBu)O] ( 4 ) and [K(18‐crown‐6)][(OCtBu)₂P] ( 5 ), respectively. The acyl‐phosphide anion 2 is thought to be formed by a photochemically induced radical process involving a transient species with triplet carbene character, prompting 1,2‐tert‐butyl group migration. A similar process is proposed for the subsequent reaction of 2 with CO to give 5 .     

Influence of Cyclopentadienyl Ring‐Tilt on Electron‐Transfer Reactions: Redox‐Induced Reactivity of Strained [2] and [3]Ruthenocenophanes

In contrast to ruthenocene [Ru(η⁵‐C₅H₅)₂] and dimethylruthenocene [Ru(η⁵‐C₅H₄Me)₂] ( 7 ), chemical oxidation of highly strained, ring‐tilted [2]ruthenocenophane [Ru(η⁵‐C₅H₄)₂(CH₂)₂] ( 5 ) and slightly strained [3]ruthenocenophane [Ru(η⁵‐C₅H₄)₂(CH₂)₃] ( 6 ) with cationic oxidants containing the non‐coordinating [B(C₆F₅)₄]^? anion was found to afford stable and isolable metal?metal bonded dicationic dimer salts [Ru(η⁵‐C₅H₄)₂(CH₂)₂]₂[B(C₆F₅)₄]₂ ( 8 ) and [Ru(η⁵‐C₅H₄)₂(CH₂)₃]₂[B(C₆F₅)₄]₂ ( 17 ), respectively. Cyclic voltammetry and DFT studies indicated that the oxidation potential, propensity for dimerization, and strength of the resulting Ru?Ru bond is strongly dependent on the degree of tilt present in 5 and 6 and thereby degree of exposure of the Ru center. Cleavage of the Ru?Ru bond in 8 was achieved through reaction with the radical source [(CH₃)₂NC(S)S?SC(S)N(CH₃)₂] (thiram), affording unusual dimer [(CH₃)₂NCS₂Ru(η⁵‐C₅H₄)(η³‐C₅H₄)C₂H₄]₂[B(C₆F₅)₄]₂ ( 9 ) through a haptotropic η⁵–η³ ring‐slippage followed by an apparent [2+2] cyclodimerization of the cyclopentadienyl ligand. Analogs of possible intermediates in the reaction pathway [C₆H₅ERu(η⁵‐C₅H₄)₂C₂H₄][B(C₆F₅)₄] [E=S ( 15 ) or Se ( 16 )] were synthesized through reaction of 8 with C₆H₅E?EC₆H₅ (E=S or Se).     

Terminal Parent Phosphanide and Phosphinidene Complexes of Zirconium(IV)

The reaction of [Zr(Tren^DMBS)(Cl)] [ Zr1 ; Tren^DMBS=N(CH₂CH₂NSiMe₂Bu^t )₃] with NaPH₂ gave the terminal parent phosphanide complex [Zr(Tren^DMBS)(PH₂)] [ Zr2 ; Zr−P=2.690(2) Å]. Treatment of Zr2 with one equivalent of KCH₂C₆H₅ and two equivalents of benzo‐15‐crown‐5 ether (B15C5) afforded an unprecedented example (outside of matrix isolation) of a structurally authenticated transition‐metal terminal parent phosphinidene complex [Zr(Tren^DMBS)(PH)][K(B15C5)₂] [ Zr3 ; Zr=P=2.472(2) Å]. DFT calculations reveal a polarized‐covalent Zr=P double bond, with a Mayer bond order of 1.48, and together with IR spectroscopic data also suggest an agostic‐type Zr⋅⋅⋅HP interaction [∡_ZrPH=66.7°] which is unexpectedly similar to that found in cryogenic, spectroscopically observed phosphinidene species. Surprisingly, computational data suggest that the Zr=P linkage is similarly polarized, and thus as covalent, as essentially isostructural U=P and Th=P analogues.     

7‐{Di­phenyl­[(tri­phenyl­phos­phine)­aurio]­phos­phine(1+)‐P}‐8‐methyl‐7,8‐dicarba‐nido‐undecaborate(1–) dichloro­methane hemi­solvate

The title compound, 7‐[(Ph₂P)Au(PPh₃)]‐8‐(CH₃)‐7,8‐nido‐C₂B₉H₁₀]·­0.5CH₂Cl₂ or [Au(C₁₅H₂₃B₉P)­(C₁₈H₁₅P)]·­0.5CH₂Cl₂, is the first reported gold derivative of the ligand [7‐­(Ph₂P)‐8‐(CH₃)‐7,8‐nido‐C₂B₉H₁₀]^?. It has a mono­nuclear structure with the gold centre in an essentially linear coordination [P—Au—P 174.041 (15)°]. The open C₂B₃ face contains one H atom that is strongly bonded to the central B atom and semi‐bridging to a neighbouring B atom [B—H distances 1.070 (16) and 1.45 (3) Å].     

Structures and Stability of Complexes of E(C6F5)3 (E = B,Al, Ga,In) with Acetonitrile

Complexes formed by interaction of E(C₆F₅)₃ (E = B, Al, Ga, In) with excess of acetonitrile (AN) were structurally characterized. Quantum chemical computations indicate that for Al(C₆F₅)₃ and In(C₆F₅)₃ the formation of a complex of 1:2 composition is more advantageous than for B(C₆F₅)₃ and Ga(C₆F₅)₃, in line with experimental observations. Formation of the solvate [Al(C₆F₅)₃ · 2AN] · AN is in agreement with predicted thermodynamic instability of [Al(C₆F₅)₃ · 3AN]. Tensimetry study of B(C₆F₅)₃ · CH₃CN reveals its stability in the solid state up to 197 °C. With the temperature increase, the complex undergoes irreversible thermal decomposition with pentafluorobenzene formation.     

Two‐Electron Reductive Carbonylation of Terminal Uranium(V) and Uranium(VI) Nitrides to Cyanate by Carbon Monoxide

Two‐electron reductive carbonylation of the uranium(VI) nitride [U(Tren^TIPS)(N)] ( 2 , Tren^TIPS=N(CH₂CH₂NSiiPr₃)₃) with CO gave the uranium(IV) cyanate [U(Tren^TIPS)(NCO)] ( 3 ). KC₈ reduction of 3 resulted in cyanate dissociation to give [U(Tren^TIPS)] ( 4 ) and KNCO, or cyanate retention in [U(Tren^TIPS)(NCO)][K(B15C5)₂] ( 5 , B15C5=benzo‐15‐crown‐5 ether) with B15C5. Complexes 5 and 4 and KNCO were also prepared from CO and the uranium(V) nitride [{U(Tren^TIPS)(N)K}₂] ( 6 ), with or without B15C5, respectively. Complex 5 can be prepared directly from CO and [U(Tren^TIPS)(N)][K(B15C5)₂] ( 7 ). Notably, 7 reacts with CO much faster than 2 . This unprecedented f‐block reactivity was modeled theoretically, revealing nucleophilic attack of the π* orbital of CO by the nitride with activation energy barriers of 24.7 and 11.3 kcal mol^?1 for uranium(VI) and uranium(V), respectively. A remarkably simple two‐step, two‐electron cycle for the conversion of azide to nitride to cyanate using 4 , NaN₃ and CO is presented.     

Synthesis,Structure, and Luminescence Properties of a {Mo6I8} Complex with (C6F5)2PO2 Ligands

Reaction of [Mo₆I₈(CH₃COO)₆]^2– with bis(pentafluorophenyl)phosphinic acid HO(O)P(C₆F₅)₂ yielded a new bright‐red luminescent complex [{Mo₆I₈}(O₂P(C₆F₅)₂)₆]^2–, isolated as (Bu₄N)(H₅O₂)[{Mo₆I₈}(O₂P(C₆F₅)₂)₆] · 3(Et₂O) · 1.5(acetone). It was characterized by X‐ray analysis, CV, ESI‐mass spectrometry, and NMR spectroscopy.     

Ionic liquids containing the triply negatively charged tricyanomelaminate anion and a B(C6F5)3 adduct anion

Room‐temperature ionic liquids containing the triply charged tricyanomelaminate (tcmel) ion [C₃N₆(CN)₃]^3? were synthesized. The 1‐methyl‐3‐methylimidazolium (MMIm), 1‐ethyl‐3‐methylimidazolium (EMIm), and 1‐butyl‐3‐methylimidazolium (BMIm) salts of the tricyanomelaminate ion have glass transition temperatures (?6, ?20, and ?30 °C) similar to those found for the analogous monomeric dicyanoamide salts. They are thermally stable up to over 200 °C and dissolve in polar organic solvents. Addition of B(C₆F₅)₃ to M₃[tcmel] (M=Na, MMIm, EMIm, BMIm) yields salts containing the very voluminous adduct ion [C₃N₆{CN ? B(C₆F₅)₃}₃]^3? (tcmel_3B). The solid‐state structure of [MMIm]₃[tcmel] shows only long cation ??? anion contacts but in large number, while the solid‐state structure of [Na(THF)₃]₃[tcmel_3B] ? 1.76 THF displays strong interactions of the sodium cation with the amido nitrogen atoms of the anion. Hence this adduct anion cannot be regarded as a weakly coordinating anion. A similar situation is found for the MMIm salt, [MMIm]₃[tcmel_3B] ? 2.66 CH₂Cl₂, in which weak hydrogen bonds with the acidic proton of the MMIm ion are observed. On the basis of computations the energetics, structural trends, and charge transfer of adduct anion formation were studied.     

Reaction of PF5·CH3CN with sulfide

Nitriles react with PF₅ and also with AsF₅, SbF₅ forming 1:1-adducts. Using C₂Cl₃F₃ as a solvent is of advantage for this reaction. PF₅·CH₃CN and [N(C₂H₅)₄]SH give [N(C₂H₅)₄][P₂S₂F₈] with a sulfur double bridge and hexafluorophosphate in acetonitrile [1]. In case of AsF₅·CH₃CN a salt with the anion [AsF₅NHCSCH₃]^? has been isolated [2]. Following products have been confirmed in a reaction mixture of PF₅·CH₃CN and SH^? in acetonitrile by NMR (³¹P and ¹⁹F): [PF₆]^?, [F₅PSPF₅]^2?,

, F₄PSH, F₃PS, HPS₂F₂, [PS₂F₂]^?, [F₅PNC(SH)CH₃]^?, [F₅PNHCSCH₃]^?, [F₅PSH]^?. With a ratio PF₅·CH₃CN: SH^? = 2:1 the S-bridge-complexes are prefered whereas in case of a ratio 1:1 the non-bridged P-complexes are the main products.     

Kronenetherkomplexe von Blei(II). Die Kristallstrukturen von [PbCl(18-Krone-6)][SbCl6], [Pb(18-Krone-6)(CH3CN)3][SbCl6]2, and [Pb(15-Krone-5)2][SbCl6]2

Crown Ether Complexes of Lead(II). The Crystal Structures of [PbCl(18-Krone-6)][SbCl₆], [Pb(18-Krone-6)(CH₃CN)₃][SbCl₆]₂ und [Pb(15-Krone-5)₂][SbCl₆]₂ . [PbCl(18-crown-6)][SbCl₆] has been prepared in low yield besides [Pb(CH₃)₂(18-crown-6)][SbCl₆]₂ by the reaction of Pb(CH₃)₂Cl₂ with antimony pentachloride in acetonitrile solution in the presence of 18-crown-6, forming pale-yellow crystals. The other two title compounds are formed as colourless crystals by the reaction of PbCl₂ with antimony pentachloride in acetonitrile solutions in the presence of 18-crown-6 and 15-crown-5, respectively. The complexes were characterized by IR spectroscopy and by crystal structure determinations. [PbCl(18-crown-6)][SbCl₆]: Space group P2₁/c, Z = 8, 5 003 observed unique reflections, R = 0.046. Lattice dimensions at - 80°C: a = 1 386.9; b = 1 642.7; c = 2 172.1 pm, β = 92.95°. The lead atom in the cation [PbCl(18-crown-6)]⁺ is surrounded in an almost hexagonal-planar construction by the six oxygen atoms of the crown ether and an axially oriented Cl atom. [Pb(18-crown-6)(CH₃CN)₃][SbCl₆]₂: Space group P1 , Z = 2, 6 128 observed unique reflections, R = 0.076. Lattice dimensions at - 70°C: a = 1 228.0; b = 1 422.9; c = 1 463.2 pm, α = 69.08°; β = 65.71°; γ = 64.51°. In the cation [Pb(18-crown-6)(CH₃CN)₃]²⁺ the lead atom is coordinated by the six oxygen atoms of the crown ether and by the three nitrogen atoms of the acetonitrile molecules. The structure determination is restricted by disorder. [Pb( 15-crown-5)₂][SbCI₆]₂: Space group P6₃/m, Z = 6, 5 857 observed unique reflections, R = 0.059. Lattice dimensions at -70°C: a = b = 2 198.5; c = 1499.4 pm, α = β = 90°, γ = 120°. In the cation [Pb(l5-crown-5)₂]² the lead atom is sandwich-like coordinated by the ten oxygen atoms of the two crown ether molecules. The structure determination is restricted by disorder.     

Stabilization of Highly Reactive “Naked Anions”: Synthesis,Crystal Structure and Vibrational Spectrum of [Na(12‐crown‐4)2]2 [P2S6] · CH3CN

The novel thiodiphosphate, [Na(12‐crown‐4)₂]₂[P₂S₆] · CH₃CN, bis[di(12‐crown‐4)sodium] hexathiodiphosphate(V) acetonitrile solvate ( 1 ) has been synthesized by the reaction of Na₂[P₂S₆] with 12‐crown‐4 in dry acetonitrile. The title compound crystallizes in the tetragonal space group P4₂/mbc (no. 135), with a = 15.184(1) Å, c = 21.406(2) Å and Z = 4 and final R1 = 0.0671 and wR2 = 0.0809. The crystal structure is characterized by discrete sodium‐bound crown‐ether sandwich cations, [Na(12‐crown‐4)₂]⁺ and [P₂S₆]^2? ions with D_2h symmetry. Sodium ion is coordinated by the eight oxygen atoms of two crown‐ether molecules to form a square antiprisma. Solvent molecules of CH₃CN are statistically disordered. Distances and angles of the [P₂S₆]^2? unit are similar to those in [K(18‐crown‐6)]₂ [P₂S₆] · 2 CH₃CN, and in K₂[P₂S₆] and Cs₂[P₂S₆]. The FT‐Raman and FT‐IR spectrum of the title compound has been recorded and interpreted, especially with respect to the P₂S₆ group and in comparison to the few known metal hexathiodiphosphates(V).     

A dimeric constrained‐geometry titanium complex linked by double Ti–CH2–Al–CH2 heterocycles

In the structure of bis({N‐[di­methyl(1η⁵‐2,3,4,6‐tetra­methyl­in­den­yl)­silyl]­cyclo­hexyl­amido‐1κN}(methyl‐3κC)‐di‐μ₃‐methyl­ene‐1:2:3κ³C;1:3:3′κ³C‐tris(pentafluorophenyl‐2κC)titanium) benzene disolvate, [Me₂Si(η⁵‐2,3,4,6‐Me₄C₉H₂)(C₆H₁₁N)]Ti[(μ₃‐CH₂)Al(C₆F₅)₃][AlMe(μ₃‐CH₂)]₂ or [Ti₂(C₂₁H₇AlF₁₅)₂(C₂₁H₃₁NSi)₂]·2C₆D₆, the dimer is located on an inversion center, and the two Ti centers are linked by double Ti(μ₃‐CH₂)Al(C₆F₅)₃AlMe(μ₃‐CH₂) heterocycles. The electron‐deficient Ti centers are further stabilized by two α‐agostic interactions between Ti and one H atom of each bridging methyl­ene group.