Der Ligandenaustausch im Kristallgitter von (PyH)2[Ta6Br12]Cl6

Ligand Replacement in the Crystal Lattice of (PyH)₂[Ta₆Br₁₂]Cl₆ Solid (PyH)₂[Ta₆Br₁₂ⁱ]Cl₆^a transforms exothermically at 210°C. In this way the Cl^a atoms outside of the complex are going instead of Brⁱ into the inside position; e.g. [Ta₆Br₁₂]Cl₆^2? → [Ta₆Br₆Cl₆]Br₆^2?. After each transformation Cl is brought in the outside position of the complex by recrystallization from a solution containing HCl. One gets in the following transformation step [Ta₆Br₃Cl₉]⁴⁺ and finally in the third step [Ta₆Br_1.5Cl_10.5]⁴⁺. Both formula are empirical formula. They consist of [Ta₆Br₆Cl₆]⁴⁺ and [Ta₆Br₂Cl₁₀]⁴⁺; and [Ta₆Br₆Cl₆]⁴⁺, [Ta₆Br₂Cl₁₀]⁴⁺ and [Ta₆Cl₁₂]⁴⁺, respectively. This result is in agreement with the theory.     

The Cocrystallization of the Cubic [Ta6Br12(H2O)6][CuBr2X2]·10H2O and Triclinic [Ta6Br12(H2O)6]X2·trans‐[Ta6Br12(OH)4(H2O)2]·18H2O (X = Cl,Br, NO3) Phases with the Coexistence of [Ta6Br12]2+ and [Ta6Br12]4+ in the Latter

Cubic [Ta₆Br₁₂(H₂O)₆][CuBr₂X₂]·10H₂O and triclinic [Ta₆Br₁₂(H₂O)₆]X₂·trans‐[Ta₆Br₁₂(OH)₄(H₂O)₂]·18H₂O (X = Cl, Br, NO₃) cocrystallize in aqueous solutions of [Ta₆Br₁₂]²⁺ in the presence of Cu²⁺ ions. The crystal structures of [Ta₆Br₁₂(H₂O)₆]Cl₂·trans‐[Ta₆Br₁₂(OH)₄(H₂O)₂]·18H₂O ( 1 ) and [Ta₆Br₁₂(H₂O)₆]Br₂·trans‐[Ta₆Br₁₂(OH)₄(H₂O)₂]·18H₂O ( 3 )have been solved in the triclinic space group P&1macr; (No. 2). Crystal data: 1 , a = 9.3264(2) Å, b = 9.8272(2) Å, c = 19.0158(4) Å, α = 80.931(1)?, β = 81.772(2)?, γ = 80.691(1)?; 3 , a = 9.3399(2) Å, b = 9.8796(2) Å, c = 19.0494(4) Å; α = 81.037(1)?, β = 81.808(1)?, γ = 80.736(1)?. 1 and 3 consist of two octahedral differently charged cluster entities, [Ta₆Br₁₂]²⁺ in the [Ta₆Br₁₂(H₂O)₆]²⁺ cation and [Ta₆Br₁₂]⁴⁺ in trans‐[Ta₆Br₁₂(OH)₄(H₂O)₂]. Average bond distances in the [Ta₆Br₁₂(H₂O)₆]²⁺ cations: 1 , Ta‐Ta, 2.9243 Å; Ta‐Brⁱ , 2.607 Å; Ta‐O, 2.23 Å; 3 , Ta‐Ta, 2.9162 Å; Ta‐Brⁱ , 2.603 Å; Ta‐O, 2.24 Å. Average bond distances in trans‐[Ta₆‐Br₁₂(OH)₄(H₂O)₂]: 1 , Ta‐Ta, 3.0133 Å; Ta‐Brⁱ, 2.586 Å; Ta‐O(OH), 2.14 Å; Ta‐O(H₂O), 2.258(9) Å; 3 , Ta‐Ta, 3.0113 Å; Ta‐Brⁱ, 2.580 Å; Ta‐O(OH), 2.11 Å; Ta‐O(H₂O), 2.23(1) Å. The crystal packing results in short O···O contacts along the c axes. Under the same experimental conditions, [Ta₆Cl₁₂]²⁺ oxidized to [Ta₆Cl₁₂]⁴⁺ , whereas [Nb₆X₁₂]²⁺ clusters were not affected by the Cu²⁺ ion.     

Darstellung von trans-[Mo6Cl8]Cl4Br22−ausgehend von kristallisierten [Mo6Cl8]Cl4(H2O)2 und die Kristallstruktur von [(C6H5)4As]2[Mo6Cl8]Cl4Br2

Preparation of trans-[Mo₆Cl₈]Cl₄Br₂^2? Starting from Crystalline [Mo₆Cl₈]Cl₄(H₂O)₂ and Crystal Structure of [(C₆H₅)₄As]₂[Mo₆Cl₈]Cl₄Br₂ The synthesis of the title compound is successful if the crystallized [(Mo₆Cl₈)Cl₄(H₂O)₂] containing the H₂O molecules in trans-position reacts with HBr + [(C₆H₅)₄As]Br in ethanol in a heterogeneous reaction. The X-ray structure investigation confirms the existence of discrete trans-Br-substituted cluster anions of composition [(Mo₆Cl₈)Cl₄Br₂]^2? in the crystal. The reaction in homogeneous solutions proceeds to Br-enriched compounds. [(C₆H₅)₄As]₂[(Mo₆Cl₈)Cl₄Br₂] crystallizes in the triclinic space group P¯1 with a = 11.071(2), b = 11.418(2), c = 12.813(2) Å, α = 116.10(2), β = 95.27(2) and γ = 94.41(2)° (?133°C). The crystal structure at ?133°C was determined from single crystal X-ray diffraction data (R₁ = 0.026). The [(Mo₆Cl₈)Cl₄Br₂]^2?-anions are not completely ordered but distributed statistically among the three positions which are possible within the limits of the ordered [Mo₆Cl₈]-cores (ratio 11:5:4). The frameworks of the anions consist of Mo₆ cluster units with (slightly distorted) octahedral arrangement of the metal atoms (d(Mo? Mo): 2.600(1) up to 2.614(1) Å), which are coordinated by the halogeno ligands in a square-pyramidal manner. The details of the structure will be discussed and compared with similar [(Mo₆X₈)Y₄] cluster units (X, Y ? Cl, Br).     

Darstellung und Schwingungsspektren von Dichloro- und Dibromodithiophosphat Die Kristallstrukturen von [PPh3Me] [PS2Cl2] und [PPh4] [PS2Br2]

Preparation and Vibrational Spectra of Dichloro and Dibromodithiophosphate. Crystal Structures of [PPh₃Me][PS₂Cl₂] and [PPh₄][PS₂Br₂] Dichloro and dibromodithiophosphates [Cat⁺][PS₂X₂^?] with a large organic cation can be obtained from P₄S₁₀, CatX and HX in CH₂Cl₂ (Cat⁺ = PPh₄⁺, PPh₃Me⁺; X = Cl, Br). The vibrational spectra (i.r. and Raman) of the [PS₂X₂]^? ions are reported and discussed; force constants were calculated. The crystal structures of [PPh₃Me][PS₂Cl₂] and [PPh₄][PS₂Br₂] were determined and refined with X-ray diffraction data. In both cases, simple anions [PS₂X₂]^? are present. [PPh₃Me][PS₂Cl₂]: orthorhombic, space group P2₁2₁2₁, a = 1089, b = 1334, c = 1476 pm, Z = 4, refinement to a residual index R = 0.046 for 1116 reflexions; the structure is isotopic with [PPh₃Me][VO₂Cl₂]. [PPh₄][PS₂Br₂]: tetragonal space group I4 , a = 1301, c = 721 pm, Z = 2, refinement to R = 0.065 for 357 reflexions; the structure is isotypic with [AsPh₄][FeCl₄] with [PS₂Br₂]^? ions occupying positions of 4 -symmetry with statistical orientation (statistical superposition of Br and S positions).     

Einzentrenmodell für die Clusterverbindung [Nb6Cl12]4+

The electronic ground state of [Nb₆Cl₁₂]⁴⁺ is calculated using a one-center-model. One obtains the observed diamagnetic character.     

Synthese und Kristallstrukturen von (PPh4)2[As2Se4Cl12] und (PPh4)2[As2Se4Br12]

Synthesis and Crystal Structures of (PPh₄)₂[As₂Se₄Cl₁₂] and (PPh₄)₂[As₂Se₄Br₁₂] The reaction of PPh₄Cl and As₂Se₃ with SOCl₂ or with chlorine in dichloromethane affords (PPh₄)₂[As₂Se₄Cl₁₂] with good yields. From PPh₄Br, As₂Se₃ and bromine the corresponding bromo compound was obtained. According to the X-ray crystal structure determinations both compounds are isotypic, crystallizing in the space group of P1 . In the anions two Se₂X₂ molecules are linked with two X^? ions forming an Se₄X₂ ring in chair conformation. Each X^?-ion is associated with an additional AsX₃ molecule (X = Cl, Br).     

Beiträge zur Chemie der Elemente Niob und Tantal. 88 [1] Die Clusterhydroxide [M6X12](OH)2 · 8 H2O mit M = Nb,Ta; X Ta = Cl,Br

Contributions to the Chemistry of Niobium and Tantalum. 88. Cluster Hydroxides [M₆X₁₂](OH)₂ · 8 H₂O with M = Nb, Ta; X = Cl, Br The cluster hydroxides [M₆X₁₂](OH)₂ · 8 H₂O with M = Nb, Ta; X = Cl, Br, have been prepared. The poor crystalline compounds could not be classified in any of the four general structure patterns of the niobium and tantalum halide compounds. Infrared spectra, magnetic and thermal behaviours of the compounds have been measured and discussed.     

Synthesen,Eigenschaften und Kristallstrukturen der Cluster‐Salze Bi6[PtBi6Cl12] und Bi2/3[PtBi6Cl12]

Syntheses, Properties and Crystal Structures of the Cluster Salts Bi₆[PtBi₆Cl₁₂] and Bi_2/3[PtBi₆Cl₁₂] Melting reactions of Bi with Pt and BiCl₃ yield shiny black, air insensitive crystals of the subchlorides Bi₆[PtBi₆Cl₁₂] and Bi_2/3[PtBi₆Cl₁₂]. Despite the substantial difference in the bismuth content the two compounds have almost the same pseudo‐cubic unit cell and follow the structural principle of a CsCl type cluster salt. Bi₆[PtBi₆Cl₁₂] consists of cuboctahedral [PtBi₆Cl₁₂]^2? clusters and Bi₆²⁺ polycations (a = 9.052(2) Å, α = 89.88(2)°, space group P 1, multiple twins). In the electron precise cluster anion, the Pt atom (18 electron count) centers an octahedron of Bi atoms whose edges are bridged by chlorine atoms. The Bi₆²⁺ cation, a nido cluster with 16 skeletal electrons, has the shape of a distorted octahedron with an opened edge. In Bi_2/3[PtBi₆Cl₁₂] the anion charge is compensated by weakly coordinating Bi³⁺ cations which are distributed statistically over two crystallographic positions (a = 9.048(2) Å, α = 90.44(3)°, space group ). Bi₆[PtBi₆Cl₁₂] is a semiconductor with a band gap of about 0.1 eV. The compound is diamagnetic at room temperature though a small paramagnetic contribution appears towards lower temperature.     

Die Kristallstrukturen von [Et3PNAsPh3]2[Ag2Br4] und [Et3PNAsPh3]2[Pd2Br6]

Crystal Structures of [Et₃PNAsPh₃]₂[Ag₂Br₄] and [Et₃PNAsPh₃]₂[Pd₂Br₆] Colourless single crystals of [Et₃PNAsPh₃]₂[Ag₂Br₄]( 1 ) and red single crystals of [Et₃PNAsPh₃]₂[Pd₂Br₆]( 2 ) have been isolated from saturated solutions in acetonitrile of equivalent mixtures of [Et₃PNAsPh₃]Br with AgBr and PdBr₂, respectively. Both complexes were characterized by IR spectroscopy and by crystal structure determinations. 1 : Space group P1¯, Z = 1, lattice dimensions at ‐70°C: a = 985.0(2), b = 1042.2(5), c = 1345.8(5) pm, α = 102.88(2)°, β = 105.73(2)°, γ = 94.94(2)°, R₁ = 0.0577. 2 : Space group P2₁/c, Z = 2, lattice dimension at ‐70°C: a = 1003.0(1), b = 1371.8(2), c = 1974.0(1) pm, β = 93.30(1)°, R₁ = 0.0458. The dimeric anions of 1 and 2 form planar, centrosymmetric complex units.     

Drei stereoisomere quadratisch-pyramidale [Ma3b2]-Komplexe: Untersuchungen zur Existenz und zur Struktur kristalliner Dimethylsulfoxid-Komplexe von Antimon- und Bismuttrichlorid

Three Stereoisomeric Square-Pyramidal Complexes [Ma₃b₂]: Investigations of the Existence and the Structures of Crystalline Dimethyl Sulfoxide Complexes of Antimony and Bismuth Trichlorides The formation of solid complexes MCl₃ · n DMSO (M = Sb, Bi; n = 1–4) was reinvestigated. In each system, only two of four presumptive complexes could be isolated as crystalline solids: SbCl₃ · DMSO ( 1 a ) was prepared for the first time, SbCl₃ · 2 DMSO ( 1 b ), BiCl₃ · 2 DMSO ( 2 b ) and BiCl · 3 DMSO ( 2 c ) were reproduced according to literature data. Evidence is presented as to the non-existence of BiCl₃ · 4 DMSO, contrary to previous claims in the literature. A unit cell determination showed 2 c to be structurally identical with the monomeric fac-octahedral complex BiCl₃(DMSO)₃ obtained fortuitously and described elsewhere [Z. anorg. allg. Chem. 620 (1994) 1037]. The compounds 1 a (monoclinic, space group P2₁/c), 1 b (monoclinic, space group P2₁/n) and 2 b (monoclinic, space group C2) represent examples of each of the three possible geometric isomers of a square-pyramidal complex [Ma₃b₂]. In the formally 1/1 adduct 1 a , which is in fact [Sb(1)Cl₃(DMSO)₂ · Sb(2)Cl₃], the Sb(1) atom of the complex unit displays square-pyramidal geometry with the DMSO ligands situated in the apical and one of the basal positions. These units are linked into chains by SbCl₃ molecules acting as Cl-acceptors. Sb(2) forms two chelating chloro-bridges with cis-Cl atoms of one neighbouring complex and a third chloro-bridge with the remaining Cl of the symmetry-related second neighbour. The resulting Cl₆-geometry around Sb(2) is distorted octahedral. 1 b consists of square-pyramidal molecules, in which the DMSO ligands occupy two basal cis-positions; the monomeric units are loosely linked through the apical Cl atoms to form a chain of octahedra sharing trans-vertices. The asymmetric unit of 2b is a square pyramid with trans-basal DMSO ligands. The pyramids are connected by symmetry-equivalent basal chlorine atoms into chains of octahedra sharing cis-vertices. 1a displays remarkably short Sb? O dative bonds (204.7/212.9 pm); the M? O bond distances of 1b and 2b are 223.0/234.6 and 234.5/238.7 pm, respectively.     

Darstellung und elektrochemisches Verhalten von [Nb(OTeF5)6]− und [Ta(OTeF5)6]−-Komplexen

Preparation and Electrochemistry of [Nb(OTeF₅)₆]^? and [Ta(OTeF₅)₆]^? Complexes Nb(OTeF₅)₅ and Ta(OTeF₅)₅ react with Cs[OTeF₅], [Et₄N][OTeF₅], and [(n-Bu)₄N][OTeF₅] to the corresponding Cs[M(OTeF₅)₆], [Et₄N][M(OTeF₅)₆], and [(n-Bu)₄N][M(OTeF₅)₆] complexes, (M = Nb, Ta). The electrochemical reduction of the niobium complex occurs in CH₂Cl₂ at ?0,69 V and in acetonitrile at ?0,60 V (vs. SCE). The tantalum complex is reduced in CH₂Cl₂ at ?1,52 V and in acetonitrile at ?1,42 V (vs. SCE).     

Thiocyanate Compounds of [Nb6Cl12]2+: The structure of A4[Nb6Cl12(NCS)6](H2O)4 (A = K,Rb, NH4)

New compounds of the general formula A₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ (A = K, Rb, NH₄) were synthesized from Nb₆Cl₁₄ and ASCN in aqueous solutions. X-ray structure refinements were performed on single-crystal data of the three compounds. They are isotypic and crystallize with the space group P1 (Z = 1) and the lattice parameters: a = 877.9(3) pm, b = 1176.6(3) pm, c = 1187.0(3) pm, α = 114.29(1)°, β = 98.96(2)°, γ = 100.91(2)° for K₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 1 ); a = 887.6(3) pm, b = 1184.0(4) pm, c = 1195.4(4) pm, α = 114.95(2)°, β = 98.84(2)°, γ = 101.31(2)° for Rb₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 2 ) and a = 886.0(4) pm, b = 1181.1(6) pm, c = 1183.9(6) pm, α = 114.49(2)°, β = 99.48(3)°, γ = 101.53(1)° for (NH₄)₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 3 ). Each centrosymmetric [Nb₆Cl₁₂(NCS)₆]^4? ion of the isotypic compounds contains six terminal thiocyanate groups being bound to the corners of the octahedral niobium cluster through the nitrogen atoms (d_{Nb? N} = 221.5(6)–224.3(6) pm, bond angles Nb? N? C 168.6(5)–176.4(6)°). The [Nb₆Cl₁₂(NCS)₆]^4? ions are linked via A? S and A? Cl interactions with the A cations. Half of the cations occur to be disordered along two crystallographic sites.     

Beiträge zur Chemie der Elemente Niob und Tantal. 84 Die Niob- und Tantalkomplexe [Me6X] X · n H2O mit Me = Nb,Ta; Xi = Cl,Br; Xa = Cl,Br, J

On the chemistry of the elements niobium and tantalum. 84. The niobium and tantalum complexes [Me₆X]X · n H₂O with Me = Nb, Ta; X¹ = Cl, Br; X^a = Cl, Br, J The known and unknown compounds mentioned in the title were prepared. In this group of compounds four different crystal structures (A, B, C, D) occur. Lattice constants are given of the six compounds with structure C which crystallize in the hexagonal system and are isotypic with Ba₂[Nb₆Cl₁₂]Cl₆. Regarding the IR-spectra and the thermal behaviour, possible principles of structure are discussed.     

Drei neue Selenoborato-closo-dodekaborate: Synthesen und Kristallstrukturen von Rb8[B12(BSe3)6], Rb4Hg2[B12(BSe3)6] und Cs4Hg2[B12(BSe3)6]

Three Novel Selenoborato- closo -dodecaborates: Syntheses and Crystal Structures of Rb₈[B₁₂(BSe₃)₆], Rb₄Hg₂[B₁₂(BSe₃)₆], and Cs₄Hg₂[B₁₂(BSe₃)₆] The three selenoborates Rb₈[B₁₂(BSe₃)₆] (P1, a = 10.512(5) Å, b = 10.450(3) Å, c = 10.946(4) Å, α = 104.53(3)°, β = 91.16(3)°, γ = 109.11(3)°, Z = 1), Cs₄Hg₂[B₁₂(BSe₃)₆] (P1, a = 9.860(2) Å, b = 10.740(2) Å, c = 11.078(2) Å, α = 99.94(3)°, β = 90.81(3)°, γ = 115.97(3)°, Z = 1), and Rb₄Hg₂[B₁₂(BSe₃)₆] (P1, a = 9.593(2) Å, b = 10.458(2) Å, c = 11.131(2) Å, α = 99.25(3)°, β = 91.16(3)°, γ = 116.30(3)°, Z = 1) were prepared from the metal selenides, amorphous boron and selenium by solid state reactions at 700 °C. These new chalcogenoborates contain B₁₂ icosahedra completely saturated with six trigonal-planar BSe₃ entities functioning as bidentate ligands to form a persubstituted closo-dodecaborate anion. The two isotypic compounds Rb₄Hg₂[B₁₂(BSe₃)₆] and Cs₄Hg₂[B₁₂(BSe₃)₆] are the first selenoborate structures containing a transition metal which are characterized by single crystal diffraction.