A 3D Analogue of Phenyllithium: Solution‐Phase,Solid‐State,and Computational Study of the Lithiacarborane [Li−CB11H11]−

The lithiacarborane [Li?CB₁₁H₁₁]^? plays a central role in carborane chemistry, as it is a key intermediate to achieve the selective functionalization of the monocarba‐closo‐dodecaborate [CB₁₁H₁₂]^? for applications in various fields. Also, it is an organometallic species of fundamental interest because it represents a 3D analogue of phenyllithium featuring an exo C?Li bond in addition to the delocalized negative endo charge of the spherical cluster. For the first time, the elusive and highly reactive endo/exo formal dianion [CB₁₁H₁₁]^2? has been isolated as its lithiate as well as zincate in pure form and fully characterized. DFT calculations corroborate the experimental findings and underscore the remarkably high reactivity of the lithiacarborane. Subsequent derivatizations demonstrate the relevance of its initial clean formation.     

Difunctionalized {closo‐1‐CB11} Clusters: 1‐ and 2‐Amino‐12‐ethynylcarba‐closo‐dodecaborates

Carba‐closo‐dodecaborate anions with two functional groups have been synthesized via a simple two‐step procedure starting from monoamino‐functionalized {closo‐1‐CB₁₁} clusters. Iodination at the antipodal boron atom provided access to [1‐H₂N‐12‐I‐closo‐1‐CB₁₁H₁₀]^? ( 1 a ) and [2‐H₂N‐12‐I‐closo‐1‐CB₁₁H₁₀]^? ( 2 a ), which have been transformed into the anions [1‐H₂N‐12‐RC?C‐closo‐1‐CB₁₁H₁₀]^? (R=H ( 1 b ), Ph ( 1 c ), Et₃Si ( 1 d )) and [2‐H₂N‐12‐RC?C‐closo‐1‐CB₁₁H₁₀]^? (R=H ( 2 b ), Ph ( 2 c ), Et₃Si ( 2 d )) by microwave‐assisted Kumada‐type cross‐coupling reactions. The syntheses of the inner salts 1‐Me₃N‐12‐RC?C‐closo‐1‐CB₁₁H₁₀ (R=H ( 1 e ), Et₃Si ( 1 f )) and 2‐Me₃N‐12‐RC?C‐closo‐1‐CB₁₁H₁₀ (R=H ( 2 e ), Et₃Si ( 2 f )) are the first examples for a further derivatization of the new anions. All {closo‐1‐CB₁₁} clusters have been characterized by multinuclear NMR and vibrational spectroscopy as well as by mass spectrometry. The crystal structures of Cs 1 a , [Et₄N] 2 a , K 1 b , [Et₄N] 1 c , [Et₄N] 2 c , 1 e , and [Et₄N][1‐H₂N‐2‐F‐12‐I‐closo‐1‐CB₁₁H₉]?0.5 H₂O ([Et₄N ]4 a ?0.5 H₂O) have been determined. Experimental spectroscopic data and especially spectroscopic data and bond properties derived from DFT calculations provide some information on the importance of inductive and resonance‐type effects for the transfer of electronic effects through the {closo‐1‐CB₁₁} cage.     

1‐Oxa‐nido‐dodecaborate [OB11H12]− from the Controlled Oxidation of the closo‐Borates [B11H11]2− and [B12H12]2−

The closo‐dodecaborate [B₁₂H₁₂]^2? is degraded at room temperature by oxygen in an acidic aqueous solution in the course of several weeks to give B(OH)₃. The degradation is induced by Ag²⁺ ions, generated from Ag⁺ by the action of H₂S₂O₈. Oxa‐nido‐dodecaborate(1?) is an intermediate anion, that can be separated from the reaction mixture as [NBzlEt₃][OB₁₁H₁₂] after five days in a yield of 18 %. The action of FeCl₃ on the closo‐undecaborate [B₁₁H₁₁]^2? in an aqueous solution gives either [B₂₂H₂₂]^2? (by fusion) or nido‐B₁₁H₁₃(OH)^? (by protonation and hydration), depending on the concentration of FeCl₃. In acetonitrile, however, [B₁₁H₁₁]^2? is transformed into [OB₁₁H₁₂]^? by Fe³⁺ and oxygen. The radical anions [B₁₂H₁₂] ^{˙ ?} and [B₁₁H₁₁] ^{˙ ?} are assumed to be the primary products of the oxidation with the one‐electron oxidants Ag²⁺ and Fe³⁺, respectively. These radical anions are subsequently transformed into [OB₁₁H₁₂]^? by oxygen. The crystal structure analysis shows that the structure of [OB₁₁H₁₂]^? is derived from the hypothetical closo‐oxaborane OB₁₂H₁₂ by removal of the B3 vertex, leaving a non‐planar pentagonal aperture with a three‐coordinate O vertex, as predicted by NMR spectra and theory.     

Synthesis and Characterization of 2‐Mono‐ and 1,2‐Diaminocarba‐closo‐dodecaborates M[1‐R‐2‐H2N‐closo‐CB11H10] (R=H,Ph, H2N,CyHN)

The first primary 2‐aminocarba‐closo‐dodecaborates [1‐R‐2‐H₂N‐closo‐CB₁₁H₁₀]^? (R=H ( 1 ), Ph ( 2 )) have been synthesized by insertion reactions of (Me₃Si)₂NBCl₂ into the trianions [7‐R‐7‐nido‐CB₁₀H₁₀]^3?. The difunctionalized species [1,2‐(H₂N)₂‐closo‐CB₁₁H₁₀] ( 3 ) and 1‐CyHN‐2‐H₃N‐closo‐CB₁₁H₁₀ (H‐ 4 ) have been prepared analogously from (Me₃Si)₂NBCl₂ and 7‐H₃N‐7‐nido‐CB₁₀H₁₂. In addition, the preparation of [Et₄N][1‐H₂N‐2‐Ph‐closo‐CB₁₁H₁₀] ([Et₄N]‐ 5 ) starting from PhBCl₂ and 7‐H₃N‐7‐nido‐CB₁₀H₁₂ is described. Methylation of the [1‐Ph‐2‐H₂N‐closo‐CB₁₁H₁₀]^? ion ( 2 ) to produce 1‐Ph‐2‐Me₃N‐closo‐CB₁₁H₁₀ ( 6 ) is reported. The crystal structures of [Et₄N]‐ 2 , [Et₄N]‐ 5 , and 6 were determined and the geometric parameters were compared to theoretical values derived from DFT and ab initio calculations. All new compounds were studied by NMR, IR, and Raman spectroscopy, MALDI mass spectrometry, and elemental analysis. The discussion of the experimental NMR chemical shifts and of selected vibrational band positions is supported by theoretical data. The thermal properties were investigated by differential scanning calorimetry (DSC). The pK_a values of 2‐H₃N‐closo‐CB₁₁H₁₁ (H‐ 1 ), 1‐H₃N‐closo‐CB₁₁H₁₀ (H‐ 7 ), and 1,2‐(H₃N)₂‐closo‐CB₁₁H₁₀ (H₂‐ 3 ) were determined by potentiometric titration and by NMR studies. The experimental results are compared to theoretical data (DFT and ab initio). The basicities of the aminocarba‐closo‐dodecaborates agree well with the spectroscopic and structural properties.     

Functionalization of closo‐Borates via Iodonium Zwitterions

A simple method for the functionalization of closo‐borates [closo‐B₁₀H₁₀]^2? ( 1 ), [closo‐1‐CB₉H₁₀]^? ( 2 ), [closo‐B₁₂H₁₂]^2? ( 3 ), [closo‐1‐CB₁₁H₁₂]^? ( 4 ), and [3,3′‐Co(1,2‐C₂B₉H₁₁)₂]^? ( 5 ) is described. Treatment of the anions and their derivatives with ArI(OAc)₂ gave aryliodonium zwitterions, which were sufficiently stable for chromatographic purification. The reactions of these zwitterions with nucleophiles provided facile access to pyridinium, sulfonium, thiol, carbonitrile, acetoxy, and amino derivatives. The synthetic results are augmented by mechanistic considerations.     

1‐Amino‐2‐fluoromonocarba‐closo‐dodecaborates: K[1‐H2N‐2‐F‐closo‐1‐CB11H10] and [Et4N][1‐H2N‐2‐F‐closo‐1‐CB11I10]

The potassium salt of the [1‐H₂N‐2‐F‐closo‐1‐CB₁₁H₁₀]^– anion ( 1 ) was obtained from an insertion reaction of Li₃[7‐H₂N‐nido‐7‐CB₁₀H₁₀] with BF₃ · OEt₂. Anion 1 was protonated to the neutral species 1‐H₃N‐2‐F‐closo‐1‐CB₁₁H₁₀ (H 1 ) and it was iodinated with ICl to the [1‐H₂N‐2‐F‐closo‐1‐CB₁₁I₁₀]^– anion ( 2 ). All species were characterized by multinuclear NMR, IR, and Raman spectroscopy as well as by elemental analysis. The structure of H 1· (CH₃)₂CO was studied by single‐crystal X‐ray diffraction and the experimentally determined bond lengths are compared to values derived from density functional calculations.     

Anionic Gold(I) Complexes—Twelve‐ and Ten‐Vertex Monocarba‐closo‐borate Anions with Carbon–Gold σ Bonds

The anionic gold(I) complexes [1‐(Ph₃PAu)‐closo‐1‐CB₁₁H₁₁]^? ( 1 ), [1‐(Ph₃PAu)‐closo‐1‐CB₉H₉]^? ( 2 ), and [2‐(Ph₃PAu)‐closo‐2‐CB₉H₉]^? ( 3 ) with gold–carbon 2c–2e σ bonds have been prepared from [AuCl(PPh₃)] and the respective carba‐closo‐borate dianion. The anions have been isolated as their Cs⁺ salts and the corresponding [Et₄N]⁺ salts were obtained by salt metathesis reactions. The salt Cs‐ 3 isomerizes in the solid state and in solution at elevated temperatures to Cs‐ 2 with ΔH_iso=(?75±5) kJ mol^?1 (solid state) and ΔH^≠=(118±10) kJ mol^?1 (solution). The compounds were characterized by vibrational and multi‐NMR spectroscopies, mass spectrometry, elemental analysis, and differential scanning calorimetry. The crystal structures of [Et₄N]‐ 1 , [Et₄N]‐ 2 , and [Et₄N]‐ 3 were determined. The bonding parameters, NMR chemical shifts, and the isomerization enthalpy of Cs‐ 3 to Cs‐ 2 are compared to theoretical data.     

Dodecahydro‐nido‐undecaborate [B11H12]3–

The deprotonation of the nido‐anion [B₁₁H₁₄]^– by two equivalents of LitBu yields the anion [B₁₁H₁₂]^3–. Three observed ¹¹B NMR shifts of this anion in the ratio 1 : 5 : 5 are in agreement with shifts calculated by the GIAO method on the basis of the ab initio computed geometry. The deprotonation can be reversed, giving back [B₁₁H₁₄]^– via [B₁₁H₁₃]^2–. The thermolysis of [Li(thp)_x]₃[B₁₁H₁₂] in thp at 80 °C leads to the closo‐borate [Li(thp)₃]₂[B₁₁H₁₁] under elimination of LiH. Anhydrous air transforms [B₁₁H₁₂]^3– into the known oxa‐nido‐dodecaborate [OB₁₁H₁₂]^–. The rhoda‐closo‐dodecaborate [L₂RhB₁₁H₁₁]^3– is formed from [B₁₁H₁₂]^3– and RhL₃Cl (L = PPh₃).     

Synthesis and Structure of (N,)C,N‐chelated Organoantimony(III) and Bismuth(III) Cations and Isolation of Their Adducts with Ag[CB11H12]

The treatment of N,C,N‐chelated antimony(III) and bismuth(III) chlorides [C₆H₃‐2,6‐(CH=NR)₂]MCl₂ [R = tBu and M = Sb ( 1 ) or Bi ( 2 ); R = Dmp and M = Sb ( 3 ) or Bi ( 4 )] (Dmp = 2,6‐Me₂C₆H₃) with one molar equivalent of Ag[CB₁₁H₁₂] led to a smooth formation of corresponding ionic pairs {[C₆H₃‐2,6‐(CH=NR)₂]MCl}⁺[CB₁₁H₁₂]^– [R = tBu and M = Sb ( 7 ) or Bi ( 8 ), R = Dmp and M = Sb ( 9 ) or Bi ( 10 )]. Similarly, the reaction of C,N‐chelated analogues [C₆H₂‐2‐(CH=NDip)‐4,6‐(tBu)₂]MCl₂ [M = Sb ( 5 ) or Bi ( 6 ), Dip = 2′,6′‐iPr₂C₆H₃] gave compounds {[C₆H₂‐2‐(CH=NDip)‐4,6‐(tBu)₂]MCl}⁺[CB₁₁H₁₂]^– [M = Sb ( 11 ) or Bi ( 12 )]. All compounds 7 – 12 were characterized with ¹H, ¹¹B and ¹³C{¹H} NMR spectroscopy, ESI‐mass spectrometry, IR spectroscopy, and molecular structures of 7 – 9 and 12 were determined by the help of single‐crystal X‐ray diffraction analysis. In contrast, all attempts to cleave also the second M–Cl bond in 7 – 12 using another molar equivalent Ag[CB₁₁H₁₂] remained unsuccessful. Nevertheless, the reaction between 7 (or 8 ) and Ag[CB₁₁H₁₂] produced unprecedented adducts of both reagents namely {[C₆H₃‐2,6‐(CH=NtBu)₂]SbCl}₂²⁺[Ag₂(CB₁₁H₁₂)₄]^2– ( 13 ) and {[C₆H₃‐2,6‐(CH=NtBu)₂]BiCl}⁺[Ag(CB₁₁H₁₂)₂]^– ( 14 ) in a reproducible manner. The molecular structures of these sparingly soluble compounds were determined by single‐crystal X‐ray diffraction analysis.     

Bismuth Undecahydro‐closo‐dodecaborane: A Retainable Intermediate of B−H Bond Activation by Bismuth(III) Cations

The [B₁₂H₁₂]^2? anion shows an extensive substitutional chemistry based on its three‐dimensional aromaticity. The replacement of functional groups can be attained by electrophilically induced substitution caused by Brønsted or Lewis acidic electrophiles (e.g. Pt²⁺). Until now, it was impossible to structurally characterize a metal‐substituted [B₁₂H₁₂]^2? cage. When an aqueous solution containing both Bi³⁺ cations and [B₁₂H₁₂]^2? anions was heated, the charge‐neutral bismuth undecahydro‐closo‐dodecaborane BiB₁₂H₁₁ was obtained, representing a new class of metalated [B₁₂H₁₂]^2? clusters. The title compound was characterized by single‐crystal X‐ray diffraction and NMR spectroscopic methods. Compared to the typical B?H bond, the short B?Bi single bond (230 pm) exhibits inverted polarity.     

Synthesis and Properties of the Weakly Coordinating Anion [Me3NB12Cl11]−

The weakly coordinating anion [Me₃NB₁₂Cl₁₁]^? has been prepared by a simple two‐step procedure. The anion [Me₃NB₁₂Cl₁₁]^? is easily obtained in batches of up to 20 g by chlorination of the known [H₃NB₁₂H₁₁]^? anion with SbCl₅ at about 190 °C and subsequent N‐methylation with methyl iodide. Starting from Na[Me₃NB₁₂Cl₁₁], several synthetically useful salts with reactive cations ([NO]⁺, [Ph₃C]⁺, and [(Et₃Si)₂H]⁺) were prepared. Full spectroscopic (NMR, IR, Raman, TGA, MS) characterization and single‐crystal X‐ray diffraction studies confirmed the identity and purity of the products. The thermal, chemical, and electrochemical stability as well as the basicity of the [Me₃NB₁₂Cl₁₁]^? anion is similar to that of the structurally related weakly coordinating 1‐carba‐closo‐dodecaborate and closo‐dodecaborate anions. The facile preparation of the [Me₃NB₁₂Cl₁₁]^? anion and its ideal chemical and physical properties make it a cheap alternative to other classes of weakly coordinating anions.     

Synthesis,crystal structure and electrochemical properties of three isocloso eleven‐vertex ferrocenecarboxylate ruthenaborane clusters

The reaction of [RuCl₂(PPh₃)₃] with closo‐[B₁₀H₁₀]^2? and C₅H₅FeC₅H₄COOH (FcCO₂H) in refluxing CH₂Cl₂ solution affords three ruthenaborane clusters: [PPh₃(H₂O)(FcCO₂)RuB₁₀H₈Cl] (1), [(PPh₃)₂ClRu(PPh₃)(FcCO₂)RuB₁₀H₉]·0.5CH₂Cl₂ (2 × 0.5CH₂Cl₂) and [PPh₃(FcCO₂)₂RuB₁₀H₈] (3). All of these compounds are characterized by FT‐IR, NMR spectroscopic techniques, elemental analysis and single‐crystal X‐ray analysis. They are all based on a closo‐type 1:2:4:2:2 {RuB₁₀} stack with the metal occupying the unique six‐connected apical position and can be considered as having isocloso structures derived from the complete capping of the open face of an arachano geometry to give a completely closed deltahedral cluster. Compounds 1 and 2 both have an exo‐polyhedral ferrocenecarboxylate that is attached with one {Ru? O} and one {B? O} bond each, resulting in one exo‐cyclic five‐membered Ru? O? C? O? B ring. There is in addition one exo‐polyhedral ruthenium atom bonded to the center {RuB₁₀} cluster via one {Ru? Ru} linkage and two {RuH_µB} bridges, which forms a closed exo‐polyhedral tetrahedron configuration in compound 2. Compound 3 has two exo‐polyhedral ferrocenecarboxylates to form two five‐membered Ru? O? C? O? B rings engendering a symmetrical conformation. All of these new 11‐vertex ruthenaboranes can be considered as having isocloso structures derived from the complete capping of the open face of an arachano geometry to give a completely closed deltahedral cluster. Copyright © 2006 John Wiley & Sons, Ltd.     

Indyllithium and the Indyl Anion [InL]−: Heavy Analogues of N‐Heterocyclic Carbenes

Reduction of the indate complex In(NON^Ar)(μ‐Cl)₂Li(OEt₂)₂ (NON^Ar=[O(SiMe₂NAr)₂]^2?; Ar=2,6‐iPr₂C₆H₃) with sodium generates the In^II diindane species [In(NON^Ar)]₂. Further reduction with a mixture of potassium and [2.2.2]crypt affords the In^I N‐heterocyclic indyl anion [In(NON^Ar)]^?, which crystallizes with a non‐contacted [K([2.2.2]crypt)]⁺ cation. The indyl anion can also be isolated as the indyllithium compound In(NON^Ar)(Li{THF}₃), which contains an In?Li bond. Density functional theory calculations show that the HOMO of the indyl anion is a metal‐centred lone pair, and preliminary reactivity studies confirm its nucleophilic behaviour.     

Undecahalo‐closo‐undecaborates [B11Hal11]2–

The closo‐undecaborate A₂[B₁₁H₁₁] (A = NBzlEt₃) can be halogenated with excess N‐chlorosuccine imide, bromine or iodine, respectively, to give the perhalo‐closo‐undecaborates A₂[B₁₁Hal₁₁] (Hal = Cl, Br, I). The chlorination in the 11 : 1 ratio of the reagents yields A₂[B₁₁HCl₁₀], whose subsequent iodination makes A₂[B₁₁Cl₁₀I] available. The three type [B₁₁Hal₁₁]^2– anions show only one and the two type [B₁₁Cl₁₀X]^2– anions (X = H, I) only two ¹¹B NMR peaks in the ratio 10 : 1, thus exhibiting the same degenerate rearrangement of the octadecahedral B₁₁ skeleton as is well‐known for [B₁₁H₁₁]^2–. The crystal structure analysis of A₂[B₁₁Br₁₁] and A₂[B₁₁I₁₁] reveals a rigid octadecahedral skeleton in the solid state, up to 330 K, whose B–B bond lengths deviate more or less from the idealized C_2v gas phase structure, but are in good accordance with the distances of A₂[B₁₁H₁₁]. Electrochemical experiments elucidate the mechanism of the known oxidation of [B₁₁H₁₁]^2– to give [B₂₂H₂₂]^2–: A first one‐electron transfer is followed by the dimerization of the [B₁₁H₁₁]^– monoanion, whereas neutral B₁₁H₁₁, a presumably most reactive species, does not play a role as an intermediate. The electrochemical oxidation of [B₁₁Hal₁₁]^2– anions also starts with a one‐electron transfer, which is perfectly reversible only in the case of Hal = Br. There is no electrochemical indication for the formation of [B₂₂Hal₂₂]^2–. The neutral species B₁₁Hal₁₁ should be a short‐lived, very reactive species.     

Reactions of mer(exo)‐ and mer(endo)‐[Co(dien)(dapo)X]2+ Isomers (X=OH,Cl, ONO2, N3)

Properties indirectly determined, or alluded to, in previous publications on the titled isomers have been measured, and the results generally support the earlier conclusions. Thus, the common five‐coordinate intermediate generated in the OH^?‐catalyzed hydrolysis of exo‐ and endo‐[Co(dien)(dapo)X]²⁺ (X=Cl, ONO₂) has the same properties as that generated in the rapid spontaneous loss of OH^? from exo‐ and endo‐[Co(dien)(dapo)OH]²⁺ (40±2% endo‐OH, 60±2% exo‐OH) and an unusually large capacity for capturing (R=[CoN₃]/[CoOH][]=1.3; exo‐[CoN₃]/endo‐[CoN₃]=2.1±0.1). Solvent exchange for spontaneous loss of OH^? from exo‐[Co(dien)(dapo)OH]²⁺ has been measured at 0.04 s^?1 (k₁, 0.50M NaClO₄, 25°) from which similar loss from the endo‐OH isomer may be calculated as 0.24 s^?1 (k₂). The OH^?‐catalyzed reactions of exo‐ and endo‐[Co(dien)(dapo)N₃]²⁺ result in both hydrolysis of coordinated via an OH^?‐limiting process =153 M ^?1 s^?1; =295 M ^?1 s^?1; K_H=1.3±0.1 M ^?1; 0.50M NaClO₄, 25.0°) and direct epimerization between the two reactants =33 M ^?1 s^?1; =110 M ^?1 s^?1; 1.0M NaClO₄, 25.0°). Comparisons are made with other rapidly reacting Co^III‐acido systems.     

Dodecahydro‐closo‐undecaborate [B11H12]–

DFT‐calculations of the geometries of the closo‐anion [B₁₁H₁₁]^2– in its ground state and in the transition state of its skeletal rearrangement and of the protonated species [B₁₁H₁₂]^– in its ground state were performed at the B3LYP/6‐31++G(d,p) level. The corresponding NMR shifts were computed on the basis of the optimized geometry by the GIAO method at the same level. Calculated and observed NMR data are in good agreement and thus prove the structure of [B₁₁H₁₂]^–, previously deduced from 2 D‐NMR spectra. The addition of water, ethanol, and pyridine to [B₁₁H₁₂]^– at low temperature gave the nido‐species [B₁₁H₁₃(OH)]^–, [B₁₁H₁₃(OEt)]^–, and [B₁₁H₁₂(py)]^–, respectively. The structures of these anions were investigated by NMR methods and the last two of them by crystal structure analyses of appropriate salts. The course of the addition reactions can be rationalized on the basis of the structurally characterized reaction components.     

Darstellung und Kristallstruktur des Lithium‐Strontium‐Hydridnitrids LiSr2H2N

Synthesis and Crystal Structure of the Lithium Strontium Hydride Nitride LiSr₂H₂N LiSr₂H₂N was synthesized by the reaction of LiH and Li₃N with elemental strontium in sealed tantalum tubes at 650 °C within seven days. This second example of a quaternary hydride nitride crystallizes orthorhombically in space group Pnma (no. 62) with the lattice constants a = 747.14(5) pm, b = 370.28(3) pm and c = 1329.86(9) pm (Z = 4). Its crystal structure contains both kinds of anions H^? and N^3? in a sixfold distorted octahedral metal cation coordination each. The coordination polyhedra [(H1)Sr₅Li]¹⁰⁺, trans‐[(H2)Sr₄Li₂]⁹⁺ and [NSr₅Li]⁸⁺ are connected via edges and corners to form a three‐dimensional network. Two crystallographically different Sr²⁺ cations exhibit a sevenfold monocapped trigonal prismatic coordination by H^? and N^3? with [(Sr1)H₅N₂]^9? and [(Sr2)H₄N₃]^11? polyhedra, wheras Li⁺ shows a nearly planar fourfold coordinative environment ([LiH₃N]^5?). Cationic double chains of edge‐shared [NSr₅Li]⁸⁺ octahedra dominate the structure according to . Running parallel to the [0 1 0] direction, they are bundled like a hexagonal rod‐packing which is interconnected by H^? anions within the (0 0 1) plane first and finally even in the third dimension (i. e. along [0 0 1]). Therefore the structure of LiSr₂H₂N is compared to that one of the closely related quaternary hydride oxide LiLa₂HO₃.     

Investigation of Large Polychloride Anions: [Cl11]−, [Cl12]2−, and [Cl13]−

For decades the chemistry of polyhalides was dominated by polyiodides and more recently also by an increasing number of polybromides. However, apart from a few structures containing trichloride anions and a single report on an octachloride dianion, [Cl₈]^2?, polychlorine compounds such as polychloride anions are unknown. Herein, we report on the synthesis and investigation of large polychloride monoanions such as [Cl₁₁]^? found in [AsPh₄][Cl₁₁], [PPh₄][Cl₁₁], and [PNP][Cl₁₁]?Cl₂, and [Cl₁₃]^? obtained in [PNP][Cl₁₃]. The polychloride dianion [Cl₁₂]^2? has been obtained in [NMe₃Ph]₂[Cl₁₂]. The novel compounds have been thoroughly characterized by NMR spectroscopy, single‐crystal Raman spectroscopy, and single‐crystal X‐ray diffraction. The assignment of their spectra is supported by molecular and periodic solid‐state quantum‐chemical calculations.     

Formation of [Bi11]3−, A Homoatomic,Polycyclic Bismuth Polyanion,by Pyridine‐Assisted Decomposition of [GaBi3]2−

Until now, polycyclic bismuth polyanions have not been known—thus discriminating bismuth from its lighter congeners. However, the synthesis of [K([2.2.2]crypt)]₃(Bi₁₁)?2 py?tol, allows us to present the first structurally characterized homoatomic, polycyclic bismuth polyanion, which exhibits the [P₁₁]^3? “ufosan” structure. It was obtained upon treatment of [K([2.2.2]crypt)]₂(GaBi₃)?en with the solvent pyridine. The binary Zintl anion [GaBi₃]^2? decomposes under oxidative coupling of pyridine molecules and release of H₂ to form the title compound. The unprecedented reaction, its products and by‐products were investigated by means of spectroscopy, spectrometry, and DFT studies. All findings reveal the specific reaction conditions to be crucial for the formation of the [Bi₁₁]^3? ion—and indicate the possibility of the generation and isolation of further, large bismuth polyanions.     

Darstellung und spektroskopische Charakterisierung der Monofluorohydro-closo-Borate [B6H5F]2− und [B12H11F]2−

Preparation and Spectroscopic Characterization of the Monofluorohydro-closo-borates [B₆H₅F]^2? and [B₁₂H₁₁F]^2? By treatment of [B₆H₆]^2? with 1-(chloromethyl)-4-fluoro-1,4-diazabicyclo[2.2.2]octane-bis(tetrafluoroborate)in acetonitrile monofluorohydro-closo-hexaborate [B₆H₅F]^2? ( 1 ) is formed in good yields. [B₁₂H₁₂]^2? reacts with unhydrous HF yielding the monofluorododecaborate [B₁₂H₁₁F]^2? ( 2 ). These compounds are separated by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose from by-products. The ¹¹B nmr spectra exhibit the characteristic patterns (1 : 4 : 1) of a monosubstituted B₆ octahedron and (1 : 5 : 5 : 1) of a monosubstituted B₁₂ icosahedron with strong downfield shifts of the ipso-B nuclei at +9.3 ppm ( 1 ) and at +9.0 ppm ( 2 ). The ¹⁹F nmr spectra reveal quartets at ?212 ppm ( 1 ) and ?209 ppm ( 2 ) proving a B? F bonding. In the i.r. spectra, for ( 1 ) in the Raman spectrum too, cage vibrations depending on the F substituent at 1195 ( 1 ) and at 1182/1154 cm^?1 ( 2 ) are observed. The Raman spectra show the B₆F stretching mode at 535 cm^?1 and the B₁₂F stretching vibration at 445 cm^?1.