Lanthanoid Antimonides Ln2Sb5 (Ln = Sm,Gd, Tb,Dy) and Rationalization of Chemical Bonding within the Antimony Polyanion by Combining the Zintl‐Klemm Concept with Bond‐Length Bond‐Strength Relationships

The title compounds are formed by peritectic reactions. Single crystals could be isolated from samples with high antimony content. Their structure was determined for Dy₂Sb₅ from four‐circle X‐ray diffractometer data: P2₁/m, a = 1306.6(1) pm, b = 416.27(4) pm, c = 1458.4(1) pm, β = 102.213(8)°, Z = 4, R = 0.061 for 2980 structure factors and 86 variable parameters. All dysprosium atoms have nine antimony neighbors forming tricapped trigonal prisms with Dy–Sb distances varying between 308 and 338 pm. The antimony atoms occupy ten different sites with greatly varying coordination. One extreme case is an antimony atom surrounded only by dysprosium atoms in trigonal prismatic arrangement, the other one is an antimony atom in distorted octahedral antimony coordination. The various antimony‐antimony interactions (with Sb–Sb distances varying between 284 and 338 pm) are rationalized by combining the Zintl‐Klemm concept with bond‐length bond‐strength considerations.     

Phosphaniminato-Komplexe von Titan(IV). Die Kristallstrukturen von [TiCl3(NPEt3)]2, [TiCl3(NPEt3)(THF)2] und [TiCl4{Me2Si(NPEt3)2}]

Phosphoraneiminato Complexes of Titanium(IV). Crystal Structures of [TiCl₃(NPEt₃)]₂, [TiCl₃(NPEt₃)(THF)₂], and [TiCl₄{Me₂Si(NPEt₃)₂}] [TiCl₃(NPEt₃)]₂ ( 1 ) is formed from titanium(IV) chloride and the silylated phosphaneimine Me₃SiNPEt₃ in dichloromethane as reddish-brown, moisture-sensitive crystals. According to the crystal structure analysis these crystals show centrosymmetric Ti₂N₂ four-membered rings with Ti–N distances of 184.7 and 210.3 pm. With tetrahydrofurane 1 forms yellow, moisture sensitive crystals of the solvate [TiCl₃(NPEt₃)(THF)₂] ( 2 ), in which the titanium atom is octahedrally coordinated. The THF molecule which is in trans position to the phosporaneiminato ligand realizes but a very weak Ti–O bond of 238.0 pm, the cis THF molecule shows a Ti–O distance of 213.7 pm. With 173.4 pm along with a TiNP bond angle of 160.0° the TiN distance is very short. The bis(phosphaneimine) complex [TiCl₄{Me₂Si(NPEt₃)₂}] ( 3 ) is formed as colourless crystals in low yield in the reaction of titanium(IV) chloride with Me₃SiNPEt₃ and trimethylcyclopentadienylsilane. In 3 the titanium atom is surrounded by four chlorine atoms in a distorted octahedral fashion and by the two N atoms of the Me₂Si(NPEt₃)₂ molecule with TiN distances of 205.6 pm.     

Crystal Structure of Mixed Crystals of the Tetra(n-butyl)ammonium Salts of cis-Tetrafluorophthalocyaninato(2−)tantalate(V) and cis-Trifluorophthalocyaninato(2−)tantalate(IV)

cis-Trichlorophthalocyaninato(2?)tantalate(V) reacts with excess tetra(n-butyl)ammonium fluoride trihydrate yielding mixed crystals of the tetra(n-butyl)ammonium salts of cis-tetrafluorophthalocyaninato(2?)tantalate(V) and cis-trifluorophthalocyaninato(2?)tantalate(IV) in the ratio five to four. These crystallize in the monoclinic space group P2₁/ n with cell parameters: a = 13.368(2) Å, b = 13.787(2) Å, c = 23.069(3) Å, β = 93.35(1)°, Z = 4. Ta^v is octacoordinated with four F atoms and four N_iso atoms in an antiprismatic cis-arrangement. The Ta^v-F distance varies from 1.919(7) to 1.966(4) Å. Ta^IV is heptacoordinated with three F atoms in a cis-arrangement. The Ta^IV-F distance varies from 1.74(1) to 1.966(4) Å. The Ta atom is located out of the centre of the N₄ plane towards the F atoms by 1.234(3) Å. The Ta–N distances range from 2.261(6) to 2.310(6) Å.     

catena‐Poly­[[bis­(nitrato)(pyrimidine)­copper(II)]‐μ‐pyrimidine‐N:N′]

The title compound, [Cu(NO₃)₂(C₄H₄N₂)₂]_n, crystallizes as a linear polymeric compound with one pyrimidine ligand bridging between two Cu^II atoms and a second pyrimidine ligand coordinated in a monodentate manner. The distorted octahedral geometry around the Cu^II atom consists of two pyrimidine N atoms at distances of 2.033 (4) and 2.025 (4) Å, and two nitrate O atoms at distances at 1.987 (3) and 1.973 (3) Å. The apical positions are occupied by an N atom of a bridging pyrimidine ligand [2.291 (4) Å] and a nitrate O atom at a long distance of 2.781 (3) Å. The basal plane is almost planar, with trans angles of 176.23 (14) and 165.34 (15)°.     

Synthese und Kristallstruktur des Goldclusters [Au16(AsPh3)8Cl6]

Synthesis and Structures of the Gold Cluster [Au₁₆(AsPh₃)₈Cl₆] Reduction of Ph₃AsAuCl with NaBH₄ in ethanol yields the gold cluster [Au₁₆(AsPh₃)₈Cl₆]. It can be crystallized from dichloromethane/diisopropyl ether in form of dark red, light sensitive crystals with the space group P2₁/n and a = 1777.68(8), b = 3372.7(1), c = 2696.2(1)pm, β = 94.166(6)°, Z = 4). The inner skeleton of the 16 Au atoms consists of a centered icosahedron of which one of the corners binds to three additional Au atoms forming a tetrahedron pendent. The shortest Au–Au distances of 264.3 to 266.6 pm correspond to the bonds to the three external Au atoms. Within the icosahedron the distances between the central atom and the peripheral atoms (273.0–279.1 pm) are distinctly shorter than the distances between the peripheral atoms (283.6–299.0 pm).     

The molecular and crystal structure of stable 5-methyl-2-methylsulfonyl-3-thiophenecarbonitrile oxide

A stable thiophene derivative, 5-methyi-2-methylsulfonyl-3-thiophenecarbonitrile oxide, which is active in reactions with dipolarophiles, was studied by means of X-ray structural analysis. In the crystalline state the structure includes two independent molecules with similar values of geometric and conformation parameters. The bond angle at the C atom of the nitrile oxide group is significantly different from 180°. The intramolecular distances between the C and S atoms in the nitrile oxide and sulfonyl groups are well below the equilibrium distance. The stability of the molecule is thought to be increased by electrostatic or donor-acceptor interactions between the atoms of these groups. The mutual orientation of the two independent molecules in the crystal is nearly orthogonal.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 725–727, April, 1993.     

The crystal structure of diiodo((o-methylthiophenyl)diphenylphosphine)palladium(II), a complex exhibiting a large structural trans influence

The crystal structure of the title compound has been determined by conventional X-ray diffraction techniques. The red diamond-shaped crystals are monoclinic, space group P2₁/n, a 8.914(4), b 16.090(12), c 14.991(5) Å, β 95.97(2)°, V 2138.44 ų, Z = 4. Refinement by full-matrix least-squares methods employed anisotropic thermal parameters for all non-hydrogen atoms and isotropic temperature factors for hydrogen atoms, and returned final residuals of R = 0.028 and R_w = 0.028.The complex is monomeric, with a square planar coordination geometry comprising the S and P atoms of the bidentate (o-methylthiophenyl)diphenylphosphine ligand and the two iodine atoms. The PdI distance trans to P is 2.658(1) Å whereas that trans to S is 2.602(1) Å. The difference of 56 standard deviations illustrates the greater structural trans influence of phosphine over thioether donors. The PdP and PdS distances of 2.250(2) and 2.288(2) Å, respectively, are normal. Two phenyl hydrogen atoms approach the Pd atom in the axial regions above and below the square plane at distances of 2.98 and 2.99 Å.     

Titan-stickstoff-verbindungen: XIX. Darstellung Und Struktur Des Spirocyclischen Titan-Silylamids Ti(NMeSiMe2MeN)2

deTi(NMeSiMe₂SiMe₂MeN)₂ (I) has been obtained from the reaction of LiNMeSiMe₂SiMe₂NMeLi with TiBr₄. It forms yellow crystals ofconsiderable stability which can be sublimed without decomposition. Its ¹H NMR, IR and Raman spectra are reported. The crystal structure of I was determined by X-ray diffraction and was refined to R = 0.059. The titanium atom in the spiro type molecule is tetrahedrally coordinated by nitrogen atoms with TIN distances of 1.905 Å SiN and SiSi distances in the slightly puckered five-membered rings are 1.733 and 2.355 Å, respectively.     

Synthesis,structure, and blue photoluminescence of the coordination chain polymer [Cd<Subscript>2</Subscript>(L)Cl<Subscript>4</Subscript>]<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript> (L = 2-(3,5-dimethylpyrazol-1-yl)-4-methylquinoline)

The complex of CdCl₂ with 2-(3,5-dimethylpyrazol-1-yl)-4-methylquinoline (L), Cd₂(L)Cl₄ (I), is synthesized. According to the X-ray diffraction data, the structure of coordination polymer I is formed by chains in which two crystallographically independent Cd atoms linked by the bridging Cl atoms have different coordination numbers (5 and 6) and different environments. Five Cl atoms form the coordination polyhedron of the Cd(2) atom: a square pyramid (Cd-Cl 2.554(3)–2.689(3) Å) completed to a bipyramid by the CI atom at a substantially longer distance of 2.865(4) Å. Two Cl atoms and the N atom of quinoline fragment L are arranged in the equatorial plane of the coordination polyhedron of the Cd(1) atom, which is a distorted trigonal bipyramid. The axial vertices are occupied by the N atom of the pyrazole cycle of L and the Cl atom. Five-membered metallocycles CdCN₃ are formed upon the coordination of bidentate chelating ligands L. The planes of L of two adjacent chains are parallel (the distances between them are ～3.5 Å), which suggests the π-π interaction between the planes. The luminescence excitation spectrum of compound I has a broad band with λ_max = 350 nm. The spectrum of bright blue photoluminescence of compound I (300 K, λ_exc = 340 nm) contains an intense band with λ_max = 420 nm.     

Intermetallic Compounds and the Use of Atomic Radii in Their Description

Metallic radii, which are obtained from atomic distances in the pure elements, are generally used for the calculation of distances in intermetallic compounds. However, the procedure for using such radii depends on the individual structural type: (a) For high coordination numbers and only slightly differing distances between atoms of the same kind and different atoms, all distances in a structure are proportional to the sum of radii, weighted according to the compositon. Such a “Vegard” relationship for ordered compounds is obeyed by intermetallic compounds with topological close packings, but strictly only if the various kinds of distances are correlated via symmetry relationships. For compounds with low coordination numbers the simple sum of radii holds for atoms participating in the shortest bond (e.g. in ionic crystals).-(b) The number of neighbors determines the size of each atom. It can be shown that the bond strength-bond length concept, developed for valence compounds, and often dealt with in the literature over the last ten years, is also applicable for alloys. On this basis a formalism is developed which uniformly describes the size of the atoms as a function of the coordination number for both the limiting cases of multiple bonds in molecules and for close packed atomic arrangements in alloys.     

Crystal Structure and Thermal Behaviour of the Mixed‐Valent Basic Mercury Nitrate HgI2(OH)(NO3)·HgIIO

Single crystals of the hitherto unknown compound Hg₂(OH)(NO₃)·HgO were obtained unintentionally during hydrothermal phase formation experiments in the system Ag—Hg— As—O. Hg₂(OH)(NO₃)·HgO (orthorhombic, Pbca, Z = 8, a = 6.4352(8), b = 11.3609(14), c = 15.958(2) Å, 1693 structure factors, 83 parameters, R1[F² > 2σ(F²)] = 0.0431) adopts a new structure type and is composed of two types of mercury‐oxygen zig‐zag‐chains running perpendicular to each other and of intermediate nitrate groups. One type of chains runs parallel [010] and consists of (Hg—Hg—OH) units with a typical Hg—Hg distance of 2.5143(10) Å for the mercury dumbbell, whereas the other type of chains runs parallel [100] and is made up of (O—Hg—O) units with short Hg—O distances of about 2.02Å. Both types of chains are concatenated by a common O atom with a slightly longer Hg—O distance of 2.25Å. The three‐dimensional assembly is completed by nitrate groups whose O atoms show Hg—O distances > 2.80Å. Weak hydrogen bonding between the OH group and one oxygen atom belonging to the nitrate group stabilizes this arrangement. Hg₂(OH)(NO₃)·HgO decomposes above 200 °C to HgO.     

catena‐Poly[[(1,10‐phenanthroline‐κ2N,N′)manganese(II)]‐di‐μ‐salicylato‐κ4O:O′]

In the title polymeric complex, [Mn(C₇H₅O₃)₂(C₁₂H₈N₂)]_n, the Mn^II atom is located on a twofold axis and displays a distorted octa­hedral coordination geometry, formed by four salicylate anions and one 1,10‐phenanthroline (phen) mol­ecule. The salicylate anions doubly bridge the Mn^II atoms to form one‐dimensional polymeric chains. A comparison of Mn—O bond distances with the corresponding Mn—O—C angles suggests a significant electrostatic content in the Mn—O bonds. A face‐to‐face distance of 3.352 (7) Å between neighbouring parallel phen planes indicates π–π stacking inter­actions between polymeric chains.     

{2‐[(3‐Amino­propyl)­amino­propyl­imino­methyl]­imidazol­ato‐N,N′,N′′,N′′′}­(methanol‐O)­copper(II) per­chlorate

In the title compound, [Cu(C₁₀H₁₈N₅)(CH₄O)]ClO₄, four N atoms from the deprotonated ligand derived from bis(3‐amino­propyl)­amine and 2‐imidazole­carbox­aldehyde are coordinated to the Cu atom. The four N atoms occupy equatorial positions with Cu—N bond distances ranging from 1.998 (2) to 2.046 (3) Å. The methanol O atom occupies one axial position with a Cu—O bond distance of 2.295 (2) Å.     

Iodophthalocyaninato(2–)thallium(III) – Synthese und Kristallstruktur

Iodophthalocyaninato(2–)thallium(III) – Synthesis and Crystal Structure Oxidation of dithalliumphthalocyaninate(2–) with excess iodine yields crystalline, blue-green iodophthalocyaninato(2–)thallium(III). It crystallizes in the orthorhombic space group Pnma (no. 62) with lattice parameters: a = 13.778(3) Å, b = 14.649(2) Å, c = 14.907(1) Å, Z = 4. The Tl atom coordinates four N_iso atoms (isoindole N atoms) and one I atom in a tetragonal pyramidal arrangement. The Tl atom is located out of the centre of the (N_iso)₄ plane towards the iodine atom by 0.959(3) Å. The Tl–I distance is 2.674(1) Å, the Tl–N_iso distances range from 2.20(1) to 2.23(1) Å (average 2.22(1) Å). The phthalocyaninate(2–) is severely distorted from planarity (concave distortion).     

trans‐Bis­[ethane‐1,2‐di­thiol­ato(2–)‐S,S′]­bis(2‐mer­cap­to­pyri­dine‐S)­tin(IV)

The title compound, [Sn(C₅H₅NS)₂(C₂H₄S₂)₂], was obtained from a 1:2 mixture of bis­(ethane‐1,2‐di­thiol­ato)­tin(IV) and 2‐mercapto­pyridine. The mol­ecules are discrete monomeric trans‐octahedral units, with the Sn^IV atom at the centre of symmetry, planar 2‐mercapto­pyridine zwitterions and SnS₂C₂ groups in twist–envelope conformations. The 2‐mercapto­pyridine ligands are monodentate and are bonded through the S atoms. The S—Sn distances between the S atom of edt (edt is ethane‐1,2‐di­thiol­ate) and the Sn atom are 2.473 (1) and 2.505 (1) Å, which are slightly longer than the S—Sn distance in Sn(edt)₂ of 2.390 (1) Å. The bond between the 2‐mercapto­pyridine S atom and the Sn atom are, remarkably, weaker than the S—Sn bond involving edt.     

Di­chloro­bis(2‐chloro‐5‐methyl­pyridine‐κN)copper(II)

In the crystals of the title compound, [CuCl₂(C₆H₆ClN)₂], the Cu atom lies on an inversion centre and is four‐coordinated by two pyridine N atoms and two Cl atoms in trans positions. The coordination geometry is square planar, with Cu—N and Cu—Cl distances of 1.986 (2) and 2.2536 (11) Å, respectively. The two pyridine rings are parallel, but twist from the CuN₂Cl₂ coordination plane by about 95° in the complex mol­ecule. There are three kinds of intermolecular C—H⃛Cl hydrogen bonds in the crystals. Two of these types generate two‐dimensional molecular networks, viewed in the direction of the a axis, and the other connects adjacent molecular networks.     

NO(HSO4), a Fairly Ionic Solid

The colourless solid NO(HSO₄), known as “lead‐chamber crystals”, was investigated ever since its first preparation more than two centuries ago. Its overall ionic nature now is confirmed by X‐ray crystallography [Pna2₁, a = 7.3558(4), b = 6.8924(3), c = 7.7017(3) Å, Z = 4]. The next neighbours of the NO⁺ cations are four hydrogensulfate oxygen atoms, forming a distorted square at a distance of about 2.5 Å from the nitrogen atom. The square pattern next to the nitrogen atom is the most widespread coordination figure about an NO⁺ ion in a nitrosyl salt. Depending on the anion, the interaction goes along with a decrease of the N–O stretch's excitation energy.     

Synthesis and Characterization of [Hg(sulfamethoxazolato)2]·2DMSO and[Cu2(μ‐CH3CO2)4(sulfamethoxazole)2]

[Hg(sulfamethoxazolato)₂]·2DMSO ( 1 ) and [Cu₂(CH₃COO)₄(sulfa‐methoxazole)₂] ( 2 ) can be obtained by the reaction of sulfamethoxazole with mercury acetate or copper acetate in methanol. The structures of the two complexes were characterized by single crystal X—ray diffractometry. Compound 1 consists of sulfamethoxazolato ligands bridging the metal ions building an unidimensional chain. Two solvent dimethylsulfoxide molecules are involved via N‐H···O hydrogen bridges. The mercury atom shows a linear primary coordination arrangement formed by two trans deprotonated sulfonamidic nitrogen atoms. The overall coordination around the metal atom may be regarded as a strongly distorted octahedron when the interactions of mercury with four sulfonamidic oxygen atoms [bond distances of 2.761(4) Å—2.971(4) Å] are also considered to build an equatorial plane and the N1 and N1′ atoms [bond distance of 2.037(5) Å] occupy the apical positions. Compound 2 is a dinuclear complex in which the copper ions are bridged by four syn‐syn acetate ligands which are related by a symmetry centre located in the centre of the complex. Each copper atom presents a nearly octahedral coordination where the equatorial plane is formed by four oxygen atoms and an isoxazolic nitrogen atom and the second copper atom occupy the apical positions.     

Layered poly[μ2‐aqua‐μ3‐dimethyl­formamide‐di‐μ3‐phenyl­phosphon­ato‐dipotassium]

The first structurally characterized alkali metal phospho­nate, the title compound, [K₂(C₆H₆O₃P)₂(C₃H₇NO)(H₂O)]_n, has a complex structure, with layers parallel to the crystallographic bc plane consisting of two crystallographically independent K atoms sandwiched between the three types of ligands present in the structure, viz. water molecules, dimethyl­formamide molecules and two crystallographically independent phenyl­phospho­nate ligands. Six O atoms coordinate to one K atom and seven to the other. The interlayer distance is 15.327 (4) Å. The K—O distances are in the range 2.739 (2)–2.932 (2) Å for the seven‐coordinate K atom and 2.650 (2)–2.821 (2) Å for the six‐coordinate K atom.     

Crystal structure and triboluminescence of the [Eu(TTA)2(NO3)(TPPO)2] complex

The crystal structure of [Eu(TTA)₂(NO₃)(TPPO)₂] (I) (TTA = thenoyltrifluoroacetone, TPPO = triphenylphosphine oxide) possessing intense triboluminescence was established by X-ray crystallography. The crystals are triclinic, noncentrocymmetrical: a = 11.047(3) Å, b = 11.794(3) Å, c = 12.537(3) Å; α = 102.635 (4)°, β = 102.088(4)°,γ = 117.765(3)°; space group P1, Z = 1. The central Eu(III) atom coordinates two oxygen atoms of two TPPO molecules at distances of 2.271 Å and 2.282 Å, two oxygen atoms of the nitrate group at distances of 2.478 Å and 2.481 Å, four oxygen atoms of two TTA ions at distances of 2.365 Å, 2.381 Å, and 2.363 Å, 2.371 Å (coordination number is 8). The coordination polyhedron of the Eu(III) atom is a distorted dodecahedron. Possible reasons for spectral differences in the Stark structure of photo-and triboluminescence of I are discussed.