Chemische und cyclovoltammetrische Untersuchung der Redoxreaktionen der Decahalogendecaborate closo‐[B10X10]2– und hypercloso‐[B10X10]· – (X = Cl,Br). Kristallstrukturanalyse von Cs2[B10Br10] · 2 H2O

Chemical and Cyclovoltammetric Investigation of the Redoxreactions of the Decahalodecaborates closo ‐[B₁₀X₁₀]^2– and hypercloso ‐[B₁₀X₁₀]^{· –} (X = Cl, Br)¹⁾. Crystal Structure Analysis of Cs₂[B₁₀Br₁₀] · 2 H₂O The oxidation of the decachloro‐closo‐decaborates(2–) Cs₂[B₁₀Cl₁₀] or [Me₄N]₂[B₁₀Cl₁₀] with Tl(CF₃COO)₃ leads to the corresponding radical monoanion hypercloso‐[B₁₀Cl₁₀] ^{· –}, which was characterized by ESR and UV/Vis spectroscopy. [B₁₀Cl₁₀] ^{· –} does not dimerize like [B₁₀H₁₀] ^{· –} but it is reduced by acetonitrile to the dianion [B₁₀Cl₁₀]^2–. Cs₂[B₁₀Cl₁₀] reacts with stronger oxidation agents like CoF₃ (in dichloromethane) or XeF₂ (in perfluorhexane), respectively, to yield B₉Cl₉ and, in traces, B₈Cl₈. In opposite to this, the decabromoderivative Cs₂[B₁₀Br₁₀] does not show any reaction with Tl(CF₃COO)₃ in acetonitrile or with CoF₃ in CH₂Cl₂. The oxidation of the dianions [B₁₀X₁₀]^2– (X = Cl, Br) was studied by electroanalytical methods (cyclic voltammetry, chronoamperometry, chronocoulometry). Formal potentials were determined for the two steps of the reaction, which do not seem to be affected by structural rearrangements. The crystal structure of Cs₂[B₁₀Br₁₀] · 2 H₂O was analyzed by single‐crystal X‐ray diffraction. Cs₂[B₁₀Br₁₀] · 2 H₂O crystallizes monoclinic (space group I2/a, (no. 15), Z = 8, a = 1361.54(9) pm, b = 1215.89(5) pm, c = 3108.4(2) pm, α = 90°, β = 97.916(8)°, γ = 90°). The closo‐cluster B₁₀Br₁₀^2– has a bicapped square antiprismatic structure with idealized D_4d symmetry.     

Kristallstruktur von Tetraphenylphosphonium-Monothiocyanatohydro-closo-Decaborat, [P(C6H5)4]2[2-(SCN)B10H9] · CH3CN

Crystal Structure of Tetraphenylphosphonium Monothiocyanatohydro-closo-Decaborate, [P(C₆H₅)₄]₂[2-(SCN)B₁₀H₉] · CH₃CN The X-ray structure determination of [P(C₆H₅)₄]₂[2-(SCN)B₁₀H₉] · CH₃CN (monoclinic, space group P2₁/n, a = 10.6040(10), b = 13.8880(9), c = 33.888(3) Å, β = 94.095(8)°, Z = 4) reveals the S coordination of the SCN substituent with a B? S distance of 1.913(6) Å and a B? S? C angle of 105.3(3)°. The SCN group is nearly linear (178.2(7)°).     

Reaktionen von [B12H12–n(OH)n]2–, n = 1, 2 mit Säuredichloriden und Kristallstruktur von Cs2[1,2-B12H10(ox)] · CH3OH

Reactions of [B₁₂H_12–n(OH)_n]^2–, n = 1, 2 with Acid Dichlorides and Crystal Structure of Cs₂[1,2-B₁₂H₁₀(ox)] · CH₃OH By treatment of [B₁₂H₁₁(OH)]^2– with organic and inorganic acid dichlorides in acetonitrile the bridged dicluster compounds [B₁₂H₁₁(ox)B₁₂H₁₁)]^4– ( 1 ), [B₁₂H₁₁(p-OOCC₆H₄COO)B₁₂H₁₁]^4– ( 2 ), [B₁₂H₁₁(m-OOCC₆H₄COO)B₁₂H₁₁]^4– ( 3 ), [B₁₂H₁₁(SO₃)B₁₂H₁₁]^4– ( 4 ), [B₁₂H₁₁(SO₄)B₁₂H₁₁]^4– ( 5 ) are obtained in good yields. The dihydroxododecaborates [1,2-B₁₂H₁₀(OH)₂]^2– and [1,7-B₁₂H₁₀(OH)₂]^2– afford clusters with an anellated ring: [1,2-B₁₂H₁₀(ox)]^2– ( 6 ), [1,2-B₁₂H₁₀(SO₄)]^2– ( 7 ) and [1,7-B₁₂H₁₀(OOC(CH₂)₈COO)]^2– ( 8 ). Isomerically pure [1,7-B₁₂H₁₀(OH)₂]^2– ( 9 ) is formed by reaction of (H₃O)₂[B₁₂H₁₂] with ethylene glycol. All new compounds are characterized by vibrational, ¹¹B, ¹³C and ¹H NMR spectra. The crystal structure of Cs₂[1,2-B₁₂H₁₀(ox)] · CH₃OH (monoclinic, space group P 2₁/c, a = 9.616(2), b = 10.817(1), c = 15.875(6) Å, β = 95.84(8)°, Z = 4) reveals a distortion of the B₁₂ icosahedron caused by the anellated six-membered heteroring.     

Darstellung und Kristallstrukturen von [P(C6H5)4][1-(NH3)B10H9] und Cs[(NH3)B12H11] · 2CH3OH

Synthesis and Crystal Structures of [P(C₆H₅)₄][1-(NH₃)B₁₀H₉] and Cs[(NH₃)B₁₂H₁₁] · 2CH₃OH The reduction of [1-(NO₂)B₁₀H₉]^2? with aluminum in alkaline solution yields [1-(NH₃)B₁₀H₉]^? and by treatment of [B₁₂H₁₂]^2? with hydroxylamine-O-sulfonic acid [(NH₃)B₁₂H₁₁]^? is formed. The crystal structures of [P(C₆H₅)₄][1-(NH₃)B₁₀H₉] (triclinic, space group P1 , a = 7.491(2), b = 13.341(2), c = 14.235(1) Å, α = 68.127(9), β = 81.85(2), γ = 86.860(3)°, Z = 2) and Cs[(NH₃)B₁₂H₁₁] · 2CH₃OH (monoclinic, space group P2₁/n, a = 14.570(2), b = 7.796(1), c = 15.076(2) Å, β = 111.801(8)°, Z = 4) reveal for both compounds the bonding of an ammine substituent to the cluster anion.     

Single Crystals of the Dodecaiodo‐closo‐dodecaborate Cs2[B12I12] · 2 CH3CN (≡ {Cs(NCCH3)}2[B12I12]) from Acetonitrile

Colourless, lath‐shaped single crystals of Cs₂[B₁₂I₁₂] · 2 CH₃CN (monoclinic, C2/m; a = 1550.3(2), b = 1273.2(1), c = 1051.5(1) pm, β = 120.97(1)°; Z = 2) are obtained by the reaction of Cs₂[B₁₂H₁₂] with an excess of I₂ and ICl (molar ratio: 1 : 2) in methylene iodide (CH₂I₂) at 180 °C (8 h) and recrystallization of the crude product from acetonitrile (CH₃CN). The crystal structure contains quasi‐icosahedral [B₁₂I₁₂]^2– anions (d(B–B) = 176–182 pm, d(B–I) = 211–218 pm) which arrange in a cubic closest‐packed fashion. All octahedral interstices are filled with centrosymmetric dimer‐cations {[Cs(N≡C–CH₃)]₂}²⁺ containing a diamond‐shaped four‐membered (Cs–N–Cs–N) ring of Cs⁺ cations and nitrogen atoms of the solvating acetonitrile molecules (d(Cs–N) = 321 pm, 2 ×). The cesium cations themselves actually reside in the distorted tetrahedral voids of the cubic [B₁₂I₁₂]^2– packing (d(Cs–I) = 402–461 pm, 10 ×) if one ignores the solvent particles.     

Syntheses,Crystal Structures,and Properties of the Isotypic Pair [Cr(H2O)6]2[B12H12]3·15H2O and [In(H2O)6]2[B12H12]3·15H2O

Single crystals of [Cr(H₂O)₆]₂[B₁₂H₁₂]₃ · 15H₂O and [In(H₂O)₆]₂[B₁₂H₁₂]₃ · 15H₂O were obtained by reactions of aqueous solutions of the acid (H₃O)₂[B₁₂H₁₂] with chromium(III) hydroxide and indium metal shot, respectively. The title compounds crystallize isotypically in the trigonal system with space group R$\bar{3}$ c (a = 1157.62(3), c = 6730.48(9) pm for the chromium, a = 1171.71(3), c = 6740.04(9) pm for the indium compound, Z = 6). The arrangement of the quasi‐icosahedral [B₁₂H₁₂]^2– dianions can be considered as stacking of two times nine layers with the sequence …ABCCABBCA… and the metal trications arrange in a cubic closest packed …abc… stacking sequence. The metal trications are octahedrally coordinated by six water molecules of hydration, while another fifteen H₂O molecules fill up the structures as zeolitic crystal water or second‐sphere hydrating species. Between these free and the metal‐bonded water molecules, bridging hydrogen bonds are found. Furthermore, there is also evidence of hydrogen bonding between the anionic [B₁₂H₁₂]^2– clusters and the free zeolitic water molecules according to B–H^δ– ··· ^δ+H–O interactions. Vibrational spectroscopy studies prove the presence of these hydrogen bonds and also show slight distortions of the dodecahydro‐closo‐dodecaborate anions from their ideal icosahedral symmetry (I_h). Thermal decomposition studies for the example of [Cr(H₂O)₆]₂[B₁₂H₁₂]₃ · 15H₂O gave no hints for just a simple multi‐stepwise dehydration process.     

Darstellung,Schwingungsspektren und Kristallstrukturen von [(Ph3P)2N]2[(W6Cl)I] · 2 Et2O · 2 CH2Cl2 und [(Ph3P)2N]2[(W6Cl)(NCS)] · 2 CH2Cl2

Synthesis, Crystal Structures, and Vibrational Spectra of [(Ph₃P)₂N]₂[(W₆Cl )I ] · 2 Et₂O · 2 CH₂Cl₂ and [(Ph₃P)₂N]₂[(W₆Cl )(NCS) ] · 2 CH₂Cl₂ By treatment of [(W₆Cl)I]^2– with (SCN)₂ in dichloromethane at –20 °C the hexaisothiocyanato cluster anion [(W₆Cl)(NCS)]^2– is formed. X‐ray structure determinations have been performed on single crystals of [(Ph₃P)₂N]₂[(W₆Cl)I] · 2 CH₂Cl₂ · 2 Et₂O ( 1 ) (triclinic, space group P1, a = 10.324(5), b = 14.908(3), c = 17.734(8) Å, α = 112.78(2)°, β = 99.13(3)°, γ = 92.02(3)°, Z = 1) and [(Ph₃P)₂N]₂[(W₆Cl)(NCS)] · 2 CH₂Cl₂ ( 2 ) (triclinic, space group P1, a = 11.115(2), b = 14.839(2), c = 17.036(3) Å, α = 104.46(1)°, β = 105.75(2)°, γ = 110.59(1)°, Z = 1). The thiocyanate ligands of 2 are bound exclusively via N atoms with W–N bond lengths of 2.091–2.107 Å, W–N–C angles of 173.1–176.9° and N–C–S angles of 178.1–179.3°. The vibrational spectra exhibit characteristic innerligand vibrations at 2067–2045 (ν_CN), 879–867 (ν_CS) and 490–482 (δ_NCS). Based on the molekular parameters of the X‐ray determination of 1 the vibrational spectra of the corresponding (n‐Bu₄N) salt of 1 are assigned by normal coordinate analysis. The valence force constants are f_d(WW) = 1.61, f_d(WI) = 1.23 and f_d(WCl) = 1.10 mdyn/Å.     

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.     

Das Lanthan‐Dodekahydro‐closo‐Dodekaborat‐Hydrat [La(H2O)9]2[B12H12]3·15 H2O und sein Oxonium‐Chlorid‐Derivat [La(H2O)9](H3O)Cl2[B12H12]·H2O

The Lanthanum Dodecahydro‐closo‐Dodecaborate Hydrate [La(H₂O)₉]₂[B₁₂H₁₂]₃·15 H₂O and its Oxonium‐Chloride Derivative [La(H₂O)₉](H₃O)Cl₂[B₁₂H₁₂]·H₂O By neutralization of an aqueous solution of the free acid (H₃O)₂[B₁₂H₁₂] with basic La₂O₃ and after isothermic evaporation colourless, face‐rich single crystals of a water‐rich lanthanum(III) dodecahydro‐closo‐dodecaborate hydrate [La(H₂O)₉]₂[B₁₂H₁₂]₃·15 H₂O are isolated. The compound crystallizes in the trigonal system with the centrosymmetric space group (a = 1189.95(2), c = 7313.27(9) pm, c/a = 6.146; Z = 6; measuring temperature: 100 K). The crystal structure of [La(H₂O)₉]₂[B₁₂H₁₂]₃·15 H₂O can be characterized by two of each other independent, one into another posed motives of lattice components. The [B₁₂H₁₂]²⁻ anions (d(B–B) = 177–179 pm; d(B–H) = 105–116 pm) are arranged according to the samarium structure, while the La³⁺ cations are arranged according to the copper structure. The lanthanum cations are coordinated in first sphere by nine oxygen atoms from water molecules in form of a threecapped trigonal prism (d(La–O) = 251–262 pm). A coordinative influence of the [B₁₂H₁₂]²⁻ anions on La³⁺ has not been determined. Since “zeolitic” water of hydratation is also present, obviously the classical H–O^δ–···^+δH–O‐hydrogen bonds play a significant role in the stabilization of the crystal structure. During the conversion of an aqueous solution of (H₃O)₂[B₁₂H₁₂] with lanthanum trichloride an anion‐mixed salt with the composition [La(H₂O)₉](H₃O)Cl₂[B₁₂H₁₂]·H₂O is obtained. The compound crystallizes in the hexagonal system with the non‐centrosymmetric space group (a = 808.84(3), c = 2064.51(8) pm, c/a = 2.552; Z = 2; measuring temperature: 293 K). The crystal structure can be characterized as a layer‐like structure, in which [B₁₂H₁₂]²⁻ anions and H₃O⁺ cations alternate with layers of [La(H₂O)₉]³⁺ cations (d(La–O) = 252–260 pm) and Cl⁻ anions along [001]. The [B₁₂H₁₂]²⁻ (d(B–B) = 176–179 pm; d(B–H) = 104–113 pm) and Cl⁻ anions exhibit no coordinative influence on La³⁺. Hydrogen bonds are formed between the H₃O⁺ cations and [B₁₂H₁₂]²⁻ anions, also between the water molecules of [La(H₂O)₉]³⁺ and Cl⁻ anions, which contribute to the stabilization of the crystal structure.     

Dodekahydro‐closo‐dodekaborate der schweren Erdalkalimetalle aus wäßriger Lösung: Ca(H2O)7[B12H12] · H2O,Sr(H2O)8[B12H12] und Ba(H2O)6[B12H12]

Dodecahydro‐ closo ‐dodecaborates of the Heavy Alkaline‐Earth Metals from Aqueous Solution: Ca(H₂O)₇[B₁₂H₁₂] · H₂O, Sr(H₂O)₈[B₁₂H₁₂], and Ba(H₂O)₆[B₁₂H₁₂] The crystalline hydrates of the heavy alkaline earth metal dodecahydro‐closo‐dodecaborates (M[B₁₂H₁₂] · n H₂O, n = 6–8; M = Ca, Sr, Ba) are easily accessible by reaction of an aqueous (H₃O)₂[B₁₂H₁₂] solution with an alkaline earth metal carbonate (MCO₃). By isothermic evaporation of the respective aqueous solution we obtained colourless single crystals which are characterized by X‐ray diffraction at room temperature. The three compounds Ca(H₂O)₇[B₁₂H₁₂] · H₂O (orthorhombic, P2₁2₁2₁; a = 1161.19(7), b = 1229.63(8), c = 1232.24(8) pm; Z = 4), Sr(H₂O)₈[B₁₂H₁₂] (trigonal, R3; a = 1012.71(6), c = 1462.94(9) pm; Z = 3) and Ba(H₂O)₆[B₁₂H₁₂] (orthorhombic, Cmcm; a = 1189.26(7) pm, b = 919.23(5) pm, c = 1403.54(9) pm; Z = 4) are neither formula‐equal nor isostructural. The structure of Sr(H₂O)₈[B₁₂H₁₂] is best described as a NaCl‐type arrangement, Ba(H₂O)₆[B₁₂H₁₂] rather forms a layer‐like and Ca(H₂O)₇[B₁₂H₁₂] · H₂O a channel‐like structure. In first sphere the alkaline earth metal cations Ca²⁺ and Sr²⁺ are coordinated by just seven and eight oxygen atoms from the surrounding water molecules, respectively. A direct coordinative influence of the quasi‐icosahedral [B₁₂H₁₂]^2– cluster anions becomes noticeable only for the Ba²⁺ cations (CN = 12) in Ba(H₂O)₆[B₁₂H₁₂]. The dehydratation of the alkaline earth metal dodecahydro‐closo‐dodecaborate hydrates has been shown to take place in several steps. Thermal treatment leads to the anhydrous compounds Ca[B₁₂H₁₂], Sr[B₁₂H₁₂] and Ba[B₁₂H₁₂] at 224, 164 and 116 °C, respectively.     

Synthesis and Crystal Structures of Cs5Nb2S4X9 – Double Salts Containing New Cluster Anions [Nb2(μ-S2)2X8]4– (X = Cl,Br)

Bis(disulfide)bridged Nb(+4) cluster halide complexes [Nb₂S₄X₈]^4– (X = Cl, Br) were prepared by acid hydrolysis of [Nb₂S₄(NCS)₈]^4– in concentrated aqueous HCl or HBr, solution from which they can be isolated as double salts Cs₅[Nb₂S₄X₈]X (X = Cl, 1 ; X = Br, 2 ). The crystal structures of 1 and 2 were determined. The isolation and X-ray structure of oxonium salt (H₃O)₅ [Nb₂S₄Cl₈]Cl ( 3 ) is also reported. 1 – 3 contain new [Nb₂S₄X₈]^4– anions which can also be viewed as excised building blocks of polymeric solids NbS₂X₂. The extra halogen resides in the center of octahedron formed by six Cs⁺ or H₃O⁺ ions. All the three salts are isostructural and crystallize in tetragonal space group Immm with the following parameters: a = 10.269(2), b = 16.343(2), c = 7.220(1) Å for 1 , a = 10.934(1), b = 16.613(2), c = 7.470(1) Å for 2 , a = 9.639(1), b = 16.031(1), c = 7.071(1) Å for 3 . The parameters of the Nb₂S₄ core are only slightly affected by the change from Cl to Br.     

Earth Alkaline Tetrathiosquarates: Syntheses and Crystal Structures of MgC4S4 · 6 H2O and CaC4S4 · 4 H2O

Concentrated aqueous solutions of magnesium chloride and calcium nitrate, respectively, allow on addition of the potassium salt of tetrathiosquarate, K₂C₄S₄ · H₂O, the isolation of the earth alkaline salts MgC₄S₄ · 6 H₂O ( 1 ) and CaC₄S₄ · 4 H₂O ( 2 ) as orange and red crystals. The crystal structure determinations ( 1 : monoclinic, C2/c, a = 17.2280(7), b = 5.9185(2), c = 13.1480(4) Å, β = 104.730(3)°, Z = 4; 2 : monoclinic, P2₁/m, a = 7.8515(3), b = 12.7705(5), c = 10.6010(4) Å, β = 93.228(2)°, Z = 4) show the presence of C₄S₄^2? ions with almost undistorted D_4h symmetry having average C–C and C–S bond lengths of 1.451Å and 1.659Å for 1 and 1.451Å and 1.655Å for 2 . The structure of 1 contains discrete, octahedral [Mg(H₂O)₆]²⁺ complexes. Several O–H····O and O–H····S bridges with H····O and H····S distances of less than 2.50Å connect cations and anions. The structure of 2 is built of concatenated, edge‐sharing Ca(H₂O)₆S₂ polyhedra. The Ca²⁺ ions have the coordination number eight, C₄S₄^2? act as a chelating ligands towards Ca²⁺ with Ca–S distances of 3.14Å. The infrared and Raman spectra show bands typical for the molecular building units of the two compounds.     

Die Oxochlorotantalate (PPh4)2[Ta2OCl9]2 · 2 CH2Cl2, (PPh4)2[Ta2OCl10] · 2 CH3CN und (K-18-Krone-6)4[Ta4O6Cl12] · 12 CH2Cl2

The Oxochlorotantalates (PPh₄)₂[Ta₂OCl₉]₂ · 2 CH₂Cl₂, (PPh₄)₂[Ta₂OCl₁₀] · 2 CH₃CN, and (K-18-crown-6)₄[Ta₄O₆Cl₁₂] · 12 CH₂Cl₂ (K-18-crown-6)₄[Ta₄O₆Cl₁₂] · 12 CH₂Cl₂ was obtained from a reaction of tantalum pentachloride, K₂S₅ and 18-crwon-6 in dichlormethane. According to its crystal structure analysis it is tetragonal (space group I 4 2d) and contains [Ta₄O₆Cl₁₂]^4– ions that have an adamantane-like Ta₄O₆ skeleton. Each K⁺ ion is coordinated by the oxygen atoms of the crown ether molecule from one side and with three Cl atoms of one [Ta₄O₆Cl₁₂]^4– ion from the opposite side. (PPh₄)₂[Ta₂OCl₁₀] · 2 CH₃CN was a product from PPh₄Cl and TaCl₅ in acetonitrile in the presence of Na₂S₄. Its crystals are monoclinic (space group P2₁/c) and contain centrosymmetric [Ta₂OCl₁₀]^2– ions having a linear Ta–O–Ta grouping with short bonds (Ta–O 189 pm). TaCl₅ and H₂S formed a solid substance (TaSCl₃) from which a small amount of (PPh₄)₂[Ta₂OCl₉]₂ · 2 CH₂Cl₂ was obtained by the reaction with PPh₄Cl in CH₂Cl₂. The anions in the monoclinic crystals (space group P2₁/n) consist of two Ta₂OCl₉^– units which are joined by chloro bridges; each Ta₂OCl₉^– unit has a nearly linear Ta–O–Ta group with differing bond lengths (179 and 202 pm). The oxygen in the compounds probably was introduced by traces of water in the crown ether, acetonitrile or H₂S, respectively.     

Fluoroborates by Cleavage of Trimethylamine‐bis(trifluoromethyl)boranes with NEt3 × 3 HF. Structures of C6F5(CF3)2B · NMe3, K[C6H5CH2(CF3)2BF], and K[C6H5(CF3)2BF]

Trimethylamine‐bis(trifluoromethyl)boranes R(CF₃)₂B · NMe₃ (R = cis/trans‐CF₃CF=CF ( 1/2 ), HC≡C ( 3 ), H₂C=CH ( 4 ), C₂H₅ ( 5 ), C₆H₅CH₂ ( 6 ), C₆F₅ ( 7 ), C₆H₅ ( 8 )) react with NEt₃ × 3 HF depending on the nature of R at 155–200 °C under replacement of the trimethylamine ligand to form the corresponding fluoro‐bis(trifluoromethyl)borates [R(CF₃)₂BF]^– ( 1 a/2 a – 8 a ). The structures of 7 , K[C₆H₅CH₂(CF₃)₂BF] ( K‐6 a ), and K[C₆H₅(CF₃)₂BF] ( K‐8 a ) have been investigated by single‐crystal X‐ray diffraction. In 7 the CF₃ groups make short repulsive contacts with NMe₃ and C₆F₅ entities – the B–CF₃ bonds being unusually long. The B–F bond lengths of K‐6 a and K‐8 a (1.446(3) and 1.452(2) Å, respectively) are long for a fluoroborate.     

New Suberato‐bridged Supramolecular Layers: Crystal Structure of [Cu2(phen)2(C8H12O4)2] · 3 H2O with phen = 1,10‐phenanthroline

The reaction of CuCl₂ · 2 H₂O, 1,10‐phenanthroline (phen), suberic acid and Na₂CO₃ in a CH₃CN–H₂O solution yielded blue needle‐like crystals of [Cu₂(phen)₂(C₈H₁₂O₄)₂] · 3 H₂O. The crystal structure (monoclinic, P2₁/n, a = 10.756(2) Å, b = 9.790(2) Å, c = 18.593(4) Å, β = 91.15(3)°, Z = 2, R = 0.043, wR² = 0.1238) consists of suberato‐bridged [Cu₂(phen)₂(C₈H₁₂O₄)_4/2] layers and hydrogen bonded H₂O molecules. The Cu atoms are coordinated by two N atoms from one bidentate chelating phen ligand and three carboxyl O atoms from different suberato ligands to form distorted [CuN₂O₃] square‐pyramids with one carboxyl O atom at the apical position (d(Cu–N) = 2.017(2), 2.043(3) Å, basal d(Cu–O) = 1.936(2), 1.951(2) Å and axial d(Cu–O) = 2.389(2) Å). Two [CuN₂O₃] square‐pyramids are condensed via a common O–O edge to a centrosymmetric [Cu₂N₄O₄] dimer with the Cu…Cu distance of 3.406(1) Å indicating no interaction between Cu atoms. The resultant [Cu₂N₄O₄] dimers are interlinked by the tridentate suberato ligands to form [Cu₂(phen)₂(C₈H₁₂O₄)_4/2] layers parallel to (101). These are assembled via π‐π stacking interactions into 3D network with H₂O molecules in the tunnels extending in the [010] direction.     

Über das Tri(phosphorano)borazinium-Monokation [H3B3(NPEt3)3Cl2]+. Kristallstrukturen von Me3SiNPR3 · BH3 (R = Et,Ph), [H3B3(NPEt3)3Cl1,85Br0,15]Br · CCl4 und des Hydrolyseproduktes NH4[B5O6(OH)4] · 2 H2O

On the Tri(phosphorano)borazinium Monocation [H₃B₃(NPEt₃)₃Cl₂]⁺. Crystal Structures of Me₃SiNPR₃ · BH₃ (R = Et, Ph), [H₃B₃(NPEt₃)₃Cl_1.85Br_0.15]Br · CCl₄, and of the Product of Hydrolysis NH₄[B₅O₆(OH)₄] · 2 H₂O The crystal structures of the donor-acceptor complexes of the silylated phosphanimines with borane which are suitable as educts for the synthesis of tri(phosphorano)borazinium ions, Me₃SiNPR₃ · BH₃ (R = Et, Ph), are described. After addition of CCl₄ the reaction of Me₃SiNPEt₃ with HBBr₂ · SMe₂ in CH₂Cl₂ leads to the tri(phosphorano)borazinium monocation [H₃B₃(NPEt₃)₃Cl₂]⁺, which is characterized crystallographically as [H₃B₃ · (NPEt₃)₃Cl_1.85Br_0.15]Br · CCl₄. It complements the series of the tri(phosphorano) cations [H₃B₃(NPEt₃)₃]³⁺ and [H₄B₃(NPEt₃)₃]²⁺ by the monocation. NH₄[B₅O₆(OH)₄] · 2 H₂O can be isolated as product of hydrolysis of the tri(phosphorano)borazinium ions; its crystal structure is redetermined, because in the literature it is based on a wrong space group. Me₃SiNPEt₃ · BH₃ ( 1 ): Space group P1, Z = 4, lattice dimensions at 213 K: a = 710.9(4), b = 1465.9(3), c = 1536.0(3) pm, α = 107.05°, β = 99.40(3)°, γ = 97.41(3)°; R = 0.0740. Me₃SiNPPh₃ · BH₃ ( 2 ): Space group P2₁/c, Z = 4, lattice dimensions at 203 K: a = 934.6(1), b = 1398.6(1), c = 1626.1(1) pm, β = 103.52(1)°; R = 0.0556. [H₃B₃(NPEt₃)₃Cl_1.85Br_0.15]Br · CCl₄ ( 3 ): Space group P2₁/n, Z = 4, lattice dimensions at 223 K: a = 1237.9(3), b = 1214.1(3), c = 2402.4(4) pm, β = 93.52(1)°. 3 holds a B₃N₃ six-membered ring in a distorted boat conformation. NH₄[B₅O₆(OH)₄] · 2 H₂O ( 4 ): Space group Aba2, Z = 4, lattice dimensions at 273 K: a = 1131.3(1), b = 1103.0(1), c = 923.0(1) pm; R = 0.0564.     

Crystal Structures of [Mn2(H2O)4(bpy)2(C8H12O4)2] · 2 H2O and [Mn(H2O)2(bpy)(C8H12O4)2/2] · H2O with bpy = 2,2′‐bipyridine

Reaction of MnSO₄ · H₂O, 2,2′‐bipyridine (bpy), suberic acid and Na₂CO₃ in CH₃OH/H₂O yielded a mixture of [Mn₂(H₂O)₄(bpy)₂(C₈H₁₂O₄)₂] · 2 H₂O ( 1 ) and [Mn(H₂O)₂‐ (bpy)(C₈H₁₂O₄)_2/2] · H₂O ( 2 ). In both complexes, the Mn atoms are octahedrally coordinated by two N atoms of one bpy ligand and four O atoms of two trans positioned H₂O molecules and two suberato ligands (d(Mn–O) = 2.107–2.328 Å; d(Mn–N) = 2.250–2.330 Å). The bis‐monodentate suberato ligands bridge Mn atoms to form dinuclear [Mn₂(H₂O)₄(bpy)₂(C₈H₁₂O₄)₂] complex molecules in 1 and 1D [Mn(H₂O)₂(bpy)(C₈H₁₂O₄)_2/2] chains in 2 . Via the intermolecular hydrogen bondings and π‐π stacking interactions, the dinuclear molecules in 1 are assembled into 2D networks parallel to (100), between which the crystal H₂O molecules are sandwiched. The polymeric chains in 2 are linked together by interchain hydrogen bonding and π‐π stacking interactions into 3D networks with the crystal H₂O molecules located in tunnels along [010]. Crystal data for 1 : P2₁/c (no. 14), a = 10.092(1) Å, b = 11.916(2) Å, c = 17.296(2) Å, β = 93.41(1)° and Z = 2. Crystal data for 2 : P2₁/c (no. 14), a = 11.176(2) Å, b = 9.688(1) Å, c = 37.842(6) Å, β = 90.06(1)° and Z = 8.     

Synthese,Kristallstruktur und thermischer Abbau von Mg(H2O)6[B12H12] · 6 H2O

Synthesis, Crystal Structure, and Thermal Decomposition of Mg(H₂O)₆[B₁₂H₁₂] · 6 H₂O By reaction of an aqueous solution of the free acid (H₃O)₂[B₁₂H₁₂] with MgCO₃ and subsequent isothermic evaporation of the resulting solution to dryness, colourless, bead‐shaped single crystals of the dodecahydrate of magnesium dodecahydro closo‐dodecaborate Mg(H₂O)₆[B₁₂H₁₂] · 6 H₂O (cubic, F4₁32; a = 1643.21(9) pm, Z = 8) emerge. The crystal structure is best described as a NaTl‐type arrangement in which the centers of gravity of the quasi‐icosahedral [B₁₂H₁₂]^2— anions (d(B—B) = 178—180 pm, d(B—H) = 109 pm) occupy the positions of Tl^— while the Mg²⁺ cations occupy the Na⁺ positions. A direct coordinative influence of the [B₁₂H₁₂]^2— units at the Mg²⁺ cations is however not noticeable. The latter are octahedrally coordinated by six water molecules forming isolated hexaaqua complex cations [Mg(H₂O)₆]²⁺ (d(Mg—O) = 206 pm, 6×). In addition, six “zeolitic” water molecules are located in the crystal structure for the formation of a strong O—H^δ+···^δ—O‐hydrogen bridge‐bonding system. The evidence of weak B—H^δ—···^δ+H—O‐hydrogen bonds between water molecules and anionic [B₁₂H₁₂]^2— clusters is also considered. Investigations on the dodecahydrate Mg[B₁₂H₁₂] · 12 H₂O (≡ Mg(H₂O)₆[B₁₂H₁₂] · 6 H₂O) by DTA/TG measurements showed that its dehydration takes place in two steps within a temperature range of 71 and 76 °C as well as at 202 °C, respectively. Thermal treatment eventually leads to the anhydrous magnesium dodecahydro closo‐dodecaborate Mg[B₁₂H₁₂].     

An Azelaato‐bridged Dinuclear Copper(II) Complex, [Cu2(phen)2(C9H14O4)2] · 6 H2O (phen = 1,10‐phenanthroline)

The title compound [Cu₂(phen)₂(C₉H₁₄O₄)₂] · 6 H₂O was prepared by the reaction of CuCl₂ · 2 H₂O, 1,10‐phenanthroline (phen), azelaic acid and Na₂CO₃ in a CH₃OH/H₂O solution. The crystal structure (monoclinic, C2/c (no. 15), a = 22.346(3), b = 11.862(1), c = 17.989(3) Å, β = 91.71(1)°, Z = 4, R = 0.0473, wR² = 0.1344 for 4279 observed reflections) consists of centrosymmetric dinuclear [Cu₂(phen)₂(C₉H₁₄O₄)₂] complexes and hydrogen bonded H₂O molecules. The Cu atom is square‐planar coordinated by the two N atoms of the chelating phen ligand and two O atoms of different bidentate bridging azelaate groups with d(Cu–N) = 2.053, 2.122(2) Å and d(Cu–O) = 1.948(2), 2.031(2) Å. Two azelaate anions bridge two common Cu atoms via the terminal O atoms (d(C–O) = 1.29(2) Å; d(C–C) = 1.550(4)–1.583(4) Å). Phen ligands of adjacent complexes cover each other at distances of about 3.62 Å, indicating π‐π stacking interaction, by which the complexes are linked to 1 D bands.     

Strukturelle Untersuchungen an Cs2[B12H12]

Structural Investigations on Cs₂[B₁₂H₁₂] The crystal structure of Cs₂[B₁₂H₁₂] has been determined from X‐ray single‐crystal data collected at room temperature. Dicesium dodecahydro‐closo‐dodecaborate crystallizes as colourless, face‐rich crystals (cubic, Fm 3; a = 1128.12(7) pm; Z = 4). Its synthesis is based on the reaction of Na[BH₄] with BF₃(O(C₂H₅)₂) via the decomposition of Na[B₃H₈] in boiling diglyme, followed by subsequent separations, precipitations (with aqueous CsOH solution) and recrystallizations. The crystal structure is best described as anti‐CaF₂‐type arrangement with the Cs⁺ cations in all tetrahedral interstices of the cubic closest‐packed host lattice of the icosahedral [B₁₂H₁₂]^2–‐cluster dianions. The intramolecular bond lengths are in the range usually found in closo‐hydroborates: 178 pm for the B–B and 112 pm for the B–H distance. Twelve hydrogen atoms belonging to four [B₁₂H₁₂]^2– icosahedra provide an almost perfect cuboctahedral coordination sphere to the Cs⁺ cations, and their distance of 313 pm (12 ×) attests for the salt‐like character of Cs₂[B₁₂H₁₂] according to {(Cs⁺)₂([B₁₂H₁₂]^2–)}. The ¹¹B{¹H}‐NMR data in aqueous (D₂O) solution are δ = –12,70 ppm (¹J_B–H = 125 Hz), and δ = –15,7 ppm (linewidth: δν_1/2 = 295 Hz) for the solid state ¹¹B‐MAS‐NMR.