(2‐Methyl­quinolin‐8‐olato)­iron(III) and ‐copper(II) complexes

The crystal structures of tris(2‐methyl­quinolin‐8‐olato‐N,O)­iron(III), [Fe­(C₁₀­H₈­NO)₃], (I), and aqua­bis(2‐methyl­quinolin‐8‐olato‐N,O)­copper(II), [Cu­(C₁₀­H₈NO)₂­(H₂O)], (II), have been determined. Compound (I) has a distorted octahedral configuration, in which the central Fe atom is coordinated by three N atoms and three O atoms from three 2‐methylquinolin‐8‐olate ligands. The three Fe—O bond distances are in the range 1.934 (2)–1.947 (2) Å, while the three Fe—N bond distances range from 2.204 (2) to 2.405 (2) Å. In compound (II), the central Cu^II atom and H₂O group lie on the crystallographic twofold axis and the coordination geometry of the Cu^II atom is close to trigonal bipyramidal, with the three O atoms in the basal plane and the two N atoms in apical positions. The Cu—N bond length is 2.018 (5) Å. The Cu—O bond length in the basal positions is 1.991 (4) Å, while the Cu—O bond length in the apical position is 2.273 (6) Å. There is an intermolecular OW—H?O hydrogen bond which links the mol­ecules into a linear chain along the b axis.     

Di­bromo(N,N′‐di‐2‐pyridyl­amine‐κ2N,N′)­palladium(II)

The palladium center of the title compound, [PdBr₂(C₁₀H₉N₃)], has a slightly distorted square‐planar conformation, with the Pd atom bonded to the two pyridine N atoms of the di‐2‐pyridyl­amine moiety and to two Br atoms. The Pd—Br and Pd—N bond lengths are 2.4168 (6)/2.4201 (5) and 2.036 (3)/2.042 (3) Å, respectively.     

A 1:1 adduct between di­methyl­tin dibromide and N‐methyl­pyrrolidinone (NMP)

The title compound, di­bromo­di­methyl(N‐methyl­pyrrolidin‐2‐one‐O)­tin(IV), [SnBr₂(CH₃)₂(C₅H₉NO)], exhibits pentacoordination of the Sn atom, with long and short Sn—Br bonds [2.6737 (4) and 2.5256 (4) Å, respectively]. The distorted trigonal–bipyramidal coordination polyhedron has two methyl groups and one Br atom in the equatorial plane, the second Br atom and the N‐methyl­pyrrolidinone (NMP) ligand occupying the apical positions.     

5‐Amino‐2,4,6‐tribromoisophthalic acid: the MAD triangle for experimental phasing

The title compound, C₈H₄Br₃NO₄, shows an extensive hydrogen‐bond network. In the crystal structure, molecules are linked into chains by COO—H...O bonds, and pairs of chains are connected by additional COO—H...O bonds. This chain bundle shows stacking interactions and weak N—H...O hydrogen bonds with adjacent chain bundles. The three Br atoms present in the molecule form an equilateral triangle. This can be easily identified in the heavy‐atom substructure when this compound is used as a heavy‐atom derivative for experimental phasing of macromolecules. The title compound crystallizes as a nonmerohedral twin.     

Low-Barrier Hydrogen Bonds in Negative Thermal Expansion Material H3[Co(CN)6]

The covalent nature of the low-barrier N−H−N hydrogen bonds in the negative thermal expansion material H₃[Co(CN)₆] has been established by using a combination of X-ray and neutron diffraction electron density analysis and theoretical calculations. This finding explains why negative thermal expansion can occur in a material not commonly considered to be built from rigid linkers. The pertinent hydrogen atom is located symmetrically between two nitrogen atoms in a double-well potential with hydrogen above the barrier for proton transfer, thus forming a low-barrier hydrogen bond. Hydrogen is covalently bonded to the two nitrogen atoms, which is the first experimentally confirmed covalent hydrogen bond in a network structure. Source function calculations established that the present N−H−N hydrogen bond follows the trends observed for negatively charge-assisted hydrogen bonds and low-barrier hydrogen bonds previously established for O−H−O hydrogen bonds. The bonding between the cobalt and cyanide ligands was found to be a typical donor–acceptor bond involving a high-field ligand and a transition metal in a low-spin configuration.     

Einkristall-Röntgenstrukturanalysen an Verbindungen mit kovalenter Metall–Metall-Bindung. IV. Die Molekül- und KristallStruktur von Mn2(CO)8[μ-Sn(Br)Mn(CO)5]2

Single Crystal X-Ray Analysis of Compounds with Covalent Metal—Metal Bonds. IV. Molecular and Crystal Structure of Mn₂(CO)₈[μ-Sn(Br) Mn(CO)₅]₂ Mn₂(CO)₈[μ-Sn(Br)Mn(CO)₅]₂ crystallizes in the monoclinic crystal system (a = 881.7 pm; b = 1237.6 pm; c = 1551.1 pm und β = 63.54°) in the space group P2₁/n with two formula units in the cell. The structure was solved by means of 2601 symmetrically independent reflections using the heavy atom method. The central molecule fragment of Mn₂(CO)₈ · [μ-Sn(Br)Mn(CO)₅]₂ consists of a planar Mn₂Sn₂ rhombus with a Mn? Mn-bond (Mn? Mn = 308.6(1) pm) across the metal ring. Besides the bonds to both Mn ring atoms each Sn(IV) atom has a terminal bond to a Br and Mn(CO)₅ ligand, building up a distorted tetrahedron around the Sn(IV) atom. The terminal ligands in Mn₂(CO)₈[μ-Sn(Br)Mn(CO)₅]₂ are in transposition with respect to the ring. The mean values for the remaining bond distances are: Sn? Mn = 263.0(1) pm; Sn? Br = 255.4(1) pm; Mn? C = 184.4(6) pm; C? O = 113.3(7) pm. A comparison of the Sn₂Mn₂ ring with similar metal rings has been given.     

[VCl3(NPPh3)(OPPh3)], ein Phosphaniminato-Komplex von Vanadium(IV)

[VCl₃(NPPh₃)(OPPh₃)], a Phosphorane Iminato Complex of Vanadium(IV) The title compound has been prepared from vanadium tetrachloride and Me₃SiNPPh₃ in the presence of OPPh₃ in CCl₄ solution, forming orange-red, moisture sensitive crystals, which were characterized by an X-ray structure determination. Space group Cc, Z = 4, 2 560 observed unique reflections, R = 0.049. Lattice dimensions at 0°C: a = 1 018(1), b = 1 826(2), c = 1 859(2) pm, β = 93.65(9)° [VCl₃(NPPh₃)(OPPh₃)] forms monomeric molecules, in which the vanadium atom is coordinated in a distorted square pyramidal fashion with the (NPPh₃)^? ligand in apical position. The three chlorine atoms and the oxygen atom of the OPPh₃ molecule occupy the basal positions. The phosphorane iminato group V?N?PPh₃ is nearly linear (bond angle VNP 161.4°), the bond lengths VN (169 pm) and PN (162 pm) correspond with double bonds.     

(2‐Amino­ethoxy)­bis(2‐thienyl)­boron

In the five‐membered ring in the title compound, (2‐amino­ethoxy)­bis(2‐thienyl)­boron, C₁₀H₁₂BNOS_2, the B atom is four‐coordinate with dimensions N—B 1.654 (3), O—B 1.479 (3), and C—B 1.606 (3) and 1.609 (3) Å. An intermolecular hydrogen bond between an amino H atom and the ethoxy O atom links the mol­ecules into infinite chains along the a axis. Only one of the two amino H atoms is involved in hydrogen bonding because there is only the one acceptor atom, the ethoxy O atom, and the molecular geometry precludes formation of a second hydrogen bond by the second amino H atom.     

Redetermination of (6R,7S,9S,11S)‐(–)‐sparteinium monoperchlorate

The structure of the title compound, C₁₅H₂₇N₂⁺·ClO₄^?, consists of a monoprotonated sparteinium cation and a perchlorate anion. The two tertiary N atoms of the cation, one perchlorate O atom and a H atom form a bifurcated hydrogen bond, the four hydrogen‐bonding atoms being nearly in the same plane.     

An MP2 study on pre-reactive complexes (CH_2)_2O … XY (X,Y = H,F,Cl,Br,I)

The structures, energies, atomic chaiges and IR spectra of complexes (CH2)2O…XY (X, Y = H, F, Cl, Br, and I) have been examined by means of ab initio molecular orbital theory at the second-order level of Moller-Plesset perturbation correction. It is found that the hydrogen bond O…H-X is non-linear. The attraction between X and the H atoms in oxirane ring causes O…H-X bond bending. The hydrogen bond slighdy weakens the bond strength of C-O, and leads the bending and stretching mode of IR to shift to the red. The calculation results show that there is no evidence of a significant extent of proton transfer to give (CH2)2OH …X- in the isolated complexes.     

A comparative study of some lithium and hydrogen‐bonded complexes: Ab initio and QTAIM studies

The nature of the interactions of cyanide with lithium and hydrogen halides was investigated using ab initio calculations and topological analysis of electron density. The computed properties of the lithium‐bonded complexes RCN···LiX (R = H, F, Cl, Br, C?CH, CH?CH₂, CH₃, C₂H₅; X = Cl, Br) were compared with those of corresponding hydrogen‐bonded complexes RCN···HX. The results show that both types of intermolecular interactions are “closed‐shell” noncovalent interactions. The effect of substitution on the interaction energy and electron density at the bond critical points of the lithium and hydrogen bonding interactions is similar. In comparison, the interaction energies of lithium‐bonded complexes are more negative than those of hydrogen‐bonded counterparts. The electrostatic interaction plays a more important role in the lithium bond than in the hydrogen bond. On complex formation, the net charge and energy of the Li atom decrease and the atomic volume increases, while the net charge and energy of the H atom increase and the atomic volume decreases. © 2013 Wiley Periodicals, Inc.     

Tetrapotassium dicarbonato­dioxo­peroxo­uranium(VI) 2.5‐hydrate,K4[U(CO3)2O2(O2)]·2.5H2O

The title compound was obtained by reacting UO₂ powder in 2 M K₂CO₃ with hydrogen peroxide. The compound contains individual [U(CO₃)₂O₂(O₂)]⁴⁻ ions, which are linked via an extended network of K atoms and hydrogen bonding. The U atom is coordinated to two trans‐axial O atoms and six O atoms in the equatorial plane, forming distorted hexagonal bipyramids. The carbonate ligands are bound to the U center in a bidentate manner, with U—O bond distances ranging from 2.438 (5) to 2.488 (5) Å. The peroxo group forms a three‐membered ring with the U atom, with U—O bond distances of 2.256 (6) and 2.240 (6) Å. The U=O bond distances of 1.806 (5) and 1.817 (5) Å, and an O—U—O angle of 175.3 (3)° are characteristic of the linear uranyl(VI) unit.     

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.     

Di‐μ‐formato‐1κ2O:2κ2O′‐di‐μ‐pyridin‐2‐olato‐1κO:2κN;1κN:2κO‐bis­[(2‐pyridone‐κO)copper(II)] acetonitrile 1.02‐solvate

In the title compound, [Cu₂(CHO₂)₂(C₅H₄NO)₂(C₅H₅NO)₂]·1.02CH₃CN, the dimeric unit is centrosymmetric, with two bidentate pyridin‐2‐olate and two bidentate formate syn–syn bridges, and two apical 2‐pyridone ligands coordinated through the O atoms. The N atom from the apical 2‐pyridone ligand is a donor of a hydrogen bond to the O atom of the bridging pyridinolate ligand of the same complex. The coordination polyhedron of the Cu atom is a distorted square pyramid.     

Dibromodiphenylstannane: isolated centrosymmetric dimers as a new structure motif for the intermolecular association of diorganotin(IV) dihalides

In the crystalline state, the low‐melting title compound [common name: diphenyltin(IV) dibromide], [SnBr₂(C₆H₅)₂], consists of distorted tetrahedral molecules with compressed halide and enlarged carbon opening angles of 102.741 (9) and 123.53 (8)°, respectively, and Sn—C and Sn—Br bond lengths of 2.109 (2)/2.113 (2) and 2.4710 (3)/2.4947 (3) Å, respectively. Intermolecular Sn...Br interactions, typical for diorganotin(IV) dihalides, R₂SnHal₂ (with Hal = Cl, Br, I), and sterically less demanding organic groups lead to the formation of a hitherto unknown association pattern consisting of centrosymmetric dimers with an antiparallel orientation of the dipole moments and two weak intermolecular Sn...Br distances of 3.8482 (3) Å between one of the two Br atoms and its neighbouring Sn atom, and vice versa. The second Br atom is not involved in intermolecular interactions and lies somewhat outside the association plane that, therefore, is not coplanar [interplanar angle = 1.750 (2)°] with the tin–halide plane. The new structure motif of intermolecular tin–halide interaction can be classified as 2a_i, which indicates the number of molecules (i.e. `2') composing the oligomer, the antiparallel orientation (i.e. `a') of their dipole moments and the centre of symmetry (i.e. `i') giving rise to the association pattern.     

Two polymorphs of (2‐carboxyethyl)(phenyl)phosphinic acid

Two polymorphs of (2‐carboxyethyl)(phenyl)phosphinic acid, C₉H₁₁O₄P, crystallize in the chiral P2₁2₁2₁ space group with similar unit‐cell parameters. They feature an essentially similar hydrogen‐bonding motif but differ slightly in their detailed geometric parameters. For both polymorphs, the unequivocal location of the hydroxy H atoms together with the expected differences in the P—O bond lengths establish unequivocally that both forms contain the S isomer; the protonated phosphinic acid and carboxy O atoms serve as hydrogen‐bond donors, while the second phosphinic acid O atom acts as a double hydrogen‐bond acceptor and the remaining carboxy O atom is not involved in hydrogen bonding. Thus, an undulating two‐dimensional supramolecular layer aggregate is formed based on an R₄³(20) ring unit. Such polymorphism derives from the rotation of the C—C single bonds between the two hydrogen‐bond‐involved carboxy and phosphinic acid moieties.     

Tetraaqua­bis[2‐(4‐pyridyl)ethanesul­fonato‐N]­zinc(II)

The title compound, [Zn(C₇H₈NO₃S)₂(H₂O)₄], has an octahedral coordination around the central Zn atom composed of two axial N atoms from the pyridine ligands and four equatorial O atoms of water mol­ecules, forming a monomeric centrosymmetric complex. The two Zn—N bond distances are 2.102 (3) Å, while the four Zn—O bond distances range from 2.114 (2) to 2.167 (2) Å. Packing is determined by hydrogen bonds formed by the water mol­ecules. The sulfonate group does not take part in coordination to the Zn atom.     

Polysulfonylamine. LXXXVIII. Drei bindungsisomere Komplexmoleküle im gleichen Kristall: Bildung und Struktur des dimeren Diorganylzinn(IV)-hydroxids [Me2{(MeSO2)2N}(phen)Sn(μ-OH)]2

Polysulfonylamines. LXXXVIII. Occurrence of Three Linkage-Isomeric Complex Molecules in One Crystal: Formation and Structure of the Dimeric Dioganyltin(IV) Hydroxide [Me₂{(MeSO₂)₂N}(phen)Sn(μ-OH)]₂ Crystal of the title compound (triclinic, space group P1 ) were obtained from Me₂Sn[N(SO₂Me)₂]₂ and 1,10-phenanthroline by adventitious hydrolysis. The structure consists of four independent [Me₂{(MeSO₂)₂N}(phen)Sn(OH)] moieties A , A ′, B , B ′ that are associated via four-membered [SnO(H)]₂ rings to form two centrosymmetric homodimers AA , BB and one asymmetric heterodimer A ′ B ′. The four crystallographically independent tin atoms attain moderately distorted pentagonalbipyramidal coordinations, the apical positions being occupied by the methyl groups and the equatorial sites by the oxygen atoms of the μ-OH groups, the nitrogen atoms of the bidentate phen ligand and one oxygen atom of the (MeSO₂)₂N? anion. Each anion is further connected to the respective complex core through an Sn? O? H…? A hydrogen bond, where the acceptor A is nitrogen in AA and the A ′ fragment of A ′ B ′, or oxygen in BB and the B ′ fragment of A ′ B ′. The distinct hydrogen bond motifs in the three linkageisomeric complex units originate from two essentially different conformations of the dimesylamide anions.     

Untersuchungen über Zinn(IV)-alkoxide. I Kristall- und Molekülstruktur des Zinn(IV)-isopropanolat-Isopropanolsolvats,Sn(OiPr)4 · i-PrOH

Investigations into Tin(IV) Alkoxides. I. Crystal and Molecular Structure of Tin(IV)-isopropoxide-Isopropanol Solvate, Sn(OⁱPr)₄ · i-PrOH The isopropanol complex of tin(IV)-isopropoxide has been prepared by the reaction of tin tetrachloride with sodium isopropoxide. The compound forms colourless, moisture sensitive crystals, which in dry air easily release the coordinated solvent molecules. The crystal and molecular structure of Sn(OⁱPr)₄ · i-PrOH has been determinated by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/c with a = 1174.2(5), b = 1428.5(3), c = 1234.1(3) pm, β = 95.37(1)° and Z = 4. The crystal structure consists of discrete, dimeric molecules in which the two tin atoms are bridged by two alkoxide groups. The octahedral coordination sphere of each tin atom is completed by one solvent molecule which, in addition, forms one hydrogen bridge to an alkoxide group of the neighboring tin atom.     

Crystal structure of [2,6-bis(3,5-dimethyl-N-pyrazolyl)pyridine]-(azido)(chloro)copper(II).

In the title compound, the coordination around the Cu atom is a distorted square-pyramid involving three N atoms from the ligand and one N atom from the azido group at the basal plane. The Cl atom is located at the apical position. The Cu atom is 0.32(5)A above the basal plane. There are three intramolecular and four weak intermolecular hydrogen bonds in the structure. IR spectra confirm the asymmetric N3 stretching vibrations of the terminal azide group.