Crystal structures of polymeric complexes of zinc(II) bromide and perchlorate with 1,4-diazoniabicyclo [2.2.2]octane-1,4-diacetate

Two zinc(II) complexes containing a flexible double betaine, namely [{Zn(L)Br₂}_n]·nH₂O (1) and [{Zn(L)₂(H₂O)₂}_n](ClO₄)_2n·4nH₂O (2) [L=1,4-diazoniabicyclo [2.2.2]octane-1,4-diacetate,⁻O₂CCH₂N⁺(CH₂CH₂)₃N⁺CH₂CO₂ ⁻], have been prepared and shown to have polymeric structures by single-crystal X-ray analysis. Complex (1) exhibits an infinite zigzag chain in which each zinc(II) atom is coordinated by two unidentate carboxylate oxygen atoms and two bromide ligands in a distorted tetrahedral geometry. Complex (2) consists of an assembly of catonic Zn(L)₂(H₂O)₂ ²⁺ moieties and discrete perchlorate anions as well as lattice water molecules. In (2) each zinc(II) atom is coordinated by two pairs of unidentate carboxylate oxygen atoms and two aqua ligands in a distorted octahedral geometry and cross-linked by skeletons of double betaine ligands to form a corrugated layer structure corresponding to the plane (100).     

Formation of copper(II) coordination polymers by a flexible double betaine: [{Cu(L)X2(H2O)} n ]·2nH2O [X=Cl,Br] and [{Cu(L)(H2O)4} n ](ClO4)2n ·2nH2O [L=−O2CCH (Me3N+)CH2CH2CH(Me3N+)CO 2 − ]

Three polymeric copper(II) complexes of a flexible double betaine, namely, [{Cu(L)Cl₂(H₂O)} _n ]·2 _n H₂O (1), [{Cu(L)Br₂(H₂O)} _n ]·2nH₂O (2), and [{Cu(L)(H₂O)₄} _n ](ClO₄)_2n ·2nH₂O (3) [L=?O₂CCH(Me₃N⁺)CH₂CH₂CH(Me₃N⁺CO₂], have been prepared and characterized by singlecrystal X-ray analysis. Isomorphous complexes (1) and (2) crystallize in space groupC2/c (No. 15) witha=17.725(3),b=5.958(2),c=19.077(3) Å, β=110.70(1)^o,V=1881.4(4) ų, Z=4 anda=18.268(4),b=5.948(3),c=19.166(5) Å, β=109.08(2)^o,V=1964.7(9) ų, Z=4, respectively. Complex (3) belongs to space groupPī (No. 2) witha=6.203(1),b=9.293(2),c=12.035(2) Å, α=86.56(2), β=87.33(3), γ=71.23(2)^o,V=655.4(2) ų and Z=1. The crystal structure of (1) and (2) features an infinite zigzag chain composed of an alternate arrangement of metal atoms and double betaines ligands, with each Cu(II) atom in a distorted CuX₂O₃ [X-Cl, Br] square-pyramidal geometry, and hydrogen bonding between adjacent chains leads to a layer structure concentrated the (200) family of planes. Complex (3) exhibits a layer structure corresponding to the (001) family of planes, in which neighboring chains constructed from the metal atoms and the double betaine ligands are cross-linked by hydrogen bonding between the aqua ligands. The Cu(II) atom is coordinated in a CuO₆ octahedral geometry with Jahn-Teller distortion.     

Synthesis and crystal structures of bimetallic hydrogen sulfates M I M II [H(SO4)2](H2O)2 (M I = K, Cs; M II = Zn, Mn) and selenate KMg[H(SeO4)2](H2O)2

Single crystals of acid salt hydrates M ^I{M ^II[H(XO₄)₂](H₂O)₂}, where M ^I, M ^II, and X are K, Zn, and S (I); K, Mn, and S (II); Cs, Mn, and S (III); or K, Mn, and Se (IV), respectively, were synthesized and studied by X-ray diffraction analysis. Compounds I–IV (space group $P\bar 1$ ) are isostructural to each other and to hydrate KMg[H(SO₄)₂](H₂O)₂ (V) studied earlier. Structures I–V, especially, the M ^I-O, M ^II-O, and X-O distances and the O?H?O (2.44–2.48 Å) and O_w-H?O (2.70–2.81 Å) hydrogen bonds, are discussed.     

Interaction of mercury(II) halides with tertiary phosphine betaines: synthesis and structural characterization of [HgX2{Ph3P(CH2)2CO2}] (X=Cl, I) and [HgCl(μ-Cl)-{Ph3P(CH2)3CO2}]2

Three new mercury(II) complexes containing tertiary phosphine betaine ligands Ph₃P⁺(CH₂)₂CO₂ ^? and Ph₃P⁺(CH₂)₃CO₂ ^? have been synthesized and fully characterized by single-crystal X-ray analysis: [HgCl₂{Ph₃(CH₂)₂CO₂}],1, space groupP2₁/n,a=9.819(2),b=14.966(4),c=14.973(5) Å, β=105.67(2)° andZ=4; [HgI₂{Ph₃(CH₂)₂CO₂}],2,P2₁/n,a=10.206(2),b=14.807(3),c=15.557(3) Å, β=107.11(2)° andZ=4; [HgCl(μ-Cl){Ph₃P(CH₂)₃CO₂}]₂,3, $P\bar 1$ ,a=10.813(2),b=11.975(3),c=11.180(2) Å, α=87.04(2), β=75.14(1), γ=81.95(1)° andZ=1. The isomorphous complexes1 and2 contain discrete mononuclear molecules in which the mercury(II) atom is unsymmetrically chelated by a Ph₃P⁺(CH₂)₂CO ₂ ^? ligand and coordinated by a pair of terminal halo ligands in a distorted tetrahedral environment, while3 consists of discrete centrosymmetric dinuclear molecules in which the betaine ligand Ph₂P⁺(CH₂)₃CO ₂ ^? acts in the chelate mode and the mercury(II) atoms are unsymmetrically bridged by a pair of chloro ligands.     

Crystal and molecular structure of four copper(II) ethylenediaminedisuccinates, [Cu2(RR,SS-Edds)] · 6H2O, Ba2[Cu(RR,SS-Edds)](ClO4)2 · 8H2O, Ba[Cu(SS-HEdds)]ClO4 · 2H2O, and Ba3[Cu2(RR,SS-Edds)2](ClO4)2 · 6H2O

Four Cu(II) complexes with the RR,SS-Edds ^4? and SS-HEdds ^3? anions are synthesized, and their crystal structures are studied. In the compounds [Cu2(RR,SS-Edds)] · 6H₂O (I) and Ba2[Cu(RR,SS-Edds)](ClO₄)₂ · 8H₂O (II), the ligand forms hexacoordinate chelate [Cu(Edds)]^2? complexes with the N atoms and O atoms of the propionate groups in the equatorial positions and the O atoms of the acetate groups in the axial vertices. In the compounds Ba[Cu(SS-HEdds)]ClO₄ · 2H₂O (III) and Ba3[Cu2(RR,SS-Edds)₂](ClO₄)₂ · 6H₂O (IV), one of the propionate arms, the protonated arm in III and the deprotonated arm in IV, does not enter into the coordination sphere of the Cu atom. An acetate arm moves to its position in the equatorial plane, and the free axial vertex is occupied by an O atom of the perchlorate ion. In I–IV, the lengths of the equatorial Cu-N and Cu-O bonds fall in the ranges 1.970–2.014 and 1.921–1.970 Å, respectively. The axial Cu-O bonds with the acetate groups and ClO ₄ ^? anions are elongated to 2.293–2.500 and 2.727–2.992 Å, respectively. In structure I, the second Cu atom acts as a counterion forming bonds with the O atoms of two water molecules and three O atoms of the Edds ligands. In II–IV, the Ba²⁺ cations are hydrated and bound to the O atoms of the anionic complexes and (except for one of the cations in IV) ClO ₄ ^? anions. The coordination number of the Ba cations is nine. The structural units in I–IV are connected into layers. In I, an extended system of hydrogen bonds links the layers into a framework. In II and III, the layers are linked only by weak hydrogen bonds, one bond per structural unit. In IV, ClO ₄ ^? anions are bound to the Ba and Cu atoms of neighboring layers, thus serving as bridges between the layers.     

Synthesis and crystal structure of thiosemicarbazide complexes of nickel(II) and copper(II)

Thiosemicarbazide complexes of nickel(II) [Ni(TSC)₂](HSal)₂ (I) and copper(II) [Cu(TSC)₂](HSal)₂ (Ia) (TSC is thiosemicarbazide and HSal is a salycilate anion), as well as complexes [Ni(TSC)₂](SO₄) · 2H₂O (II) and [Ni(TSC)₃]Cl₂ · H₂O (III), are synthesized and characterized by IR spectroscopy and X-ray diffraction. Monoclinic crystals I and Ia are isostructural; space group P2₁/n, Z = 2. Crystals II are monoclinic, space group P2₁/m, Z = 2. Crystals III are orthorhombic, space group Pbca, Z = 8. In I and Ia, two planar salycilate anions sandwich a planar centrosymmetric [Ni(TSC)₂]²⁺ cation to form a supermolecule. The cation and anions are additionally bound by hydrogen bonds. Other hydrogen bonds connect supermolecules into planar layers. In structure II, centrosymmetric [Ni(TSC)₂]²⁺ cations are connected by ??-stacking interactions into supramolecular ensembles of a specific type. The ensembles, water molecules, and (SO₄)^2? anions are bound in the crystal via hydrogen bonds. In the [Ni(TSC)₃]²⁺ cation of structure III, ligands coordinate the Ni atom by the bidentate chelate pattern with the formation of five-membered metallocycles. These metallocycles have an envelope conformation unlike those in I and II, which are planar. In III (unlike in analogous complexes), a meridional isomer of the coordination octahedron of the Ni atom is formed. Together with Cl1^? and Cl2^? anions, cations form supermolecules, which are packed into planar layers with a square-cellular structure. The layers are linked by hydrogen bonds formed by crystallization water molecules that are located between the layers.     

Effect of the acid-base interactions in a solution on the composition of the coordination sphere of aluminum and gallium complexonates

Hydroxocomplexonate K₂[GaEdta(OH)] · 6H₂O (I) and nitronium salts BH⁺GaEdta · 4H₂O (II) and BH⁺AlEdta · 4H₂O (IV) are synthesized from aqueous solutions at pH 8, 6, and 7, respectively. AlHEdta(H₂O) (III) is isolated from an acid solution (pH 1.5). Structures I, II, and IV are determined by single-crystal X-ray diffraction. The X-ray powder diffraction analysis of III has revealed that its crystals are not isostructural with those of similar complexes of other metals. Crystals I–IV are monoclinic. The unit cell parameters are a = 10.482(1), 15.735(4), 5.768(4), and 15.756(4) Å; b = 10.442(2), 12.511(2), 14.884(11), and 12.453(3) Å; c = 19.590(4), 17.330(5), 19.113(12), and 17.328(6) Å; β = 101.30(2)°, 104.54(2)°, 90.74(5)°, and 104.75(2)° for I–IV, respectively.     

Crystal structures of cesium and dimethylammonium cupradecaborates, Cs[CuB10H10] and (CH3)2 NH2[CuB10H10]

The crystal structures of Cs[CuB₁₀H₁₀] (I) and (CH₃)₂NH₂[CuB₁₀H₁₀] (II) are studied (R = 0.0398 and 0.0510 for 1225 and 2728 observed reflections in I and II, respectively). Crystals I and II are built of [(CuB₁₀H₁₀)^?]∞ anionic chains and cations. The distorted tetrahedral coordination of the Cu⁺ ions is formed by four pairs of B-H atoms from two polyhedral anions. The Cu-B bond lengths in I and II are 2.159–2.287(6) and 2.130–2.285(9) Å, respectively. The coordination of the Cu⁺ ions in II includes only edges between apical and equatorial vertices of the anions. In I, both the edges of the apical belt and those between two equatorial vertices are involved in coordination. The ability of the B₁₀H ₁₀ ^2? anion to coordinate metals by the equatorial edge is established for the first time.     

Crystal structures of acid ethylenediaminetetraacetates [Cd(H2 Edta)(H2O)] · 2H2O and [Mn(H2O)4][Mn(HEdta)(H2O)]2 · 4H2O

The crystal structures of [Cd(H₂ Edta)(H₂O)] · 2H₂O (I) and [Mn(H₂O)₄][Mn(HEdta)(H₂O)]₂ · 4H₂O (II) are studied by X-ray diffraction [R ₁ = 0.0209 (0.0272), wR ₂ = 0.0571 (0.0730) for 2551 (4025) reflections with I > 2σ(I) in I (II), respectively]. Structure I contains mononuclear [Cd(H₂ Edta)(H₂O)] complexes with the C ₂ symmetry, and structure II contains centrosymmetric trinuclear [Mn(H₂O)₄][Mn(HEdta)(H₂O)]₂ complexes. In I and II, the protonated ligands are hexadentate (2N + 4O), and the water molecule increases the coordination number of the metal atom to seven. The acid protons participate in short intermolecular hydrogen bonds, which are symmetric in II and asymmetric in I.     

Complexes in the Ni2+-imidazole-RN(CH2COO−)2 systems. The crystal structures of tris(imidazole)iminodiacetatonickel(II) monohydrate, hexa(imidazole)nickel(II) bis(N-methyliminodiacetato)nickelate(II) hexahydrate, and tetra(aqua)bis(imidazole)nickel(II) bis(N-benzyliminodiacetato)nickelate(II)

Crystals of different compositions, namely, [Ni(Ida)(Im)₃] ? H₂O (I), [Ni(Im)₆][Ni(Mida)₂] ? 6H₂O (II), and [Ni(Im)₂(H₂O)₄][Ni(Bida)₂] (III), have been precipitated from aqueous solutions of the Ni²⁺-Lig ^2?-Im systems, where Lig ^2? is Ida, Mida, and Bida, respectively. The crystal structures of I–III are determined by X-ray diffraction analysis (R = 0.0307, 0.0348, and 0.0302 for 3061, 4706, and 2882 reflections, respectively). Crystals I are built of monomeric mixed-ligand complexes and molecules of crystallization water, which are interlinked by hydrogen bonds into a three-dimensional framework. In II and III, the ligands Lig ^2? and Im form charged complexes separately. In II, the cationic and anionic layers of the complexes alternate along the c-axis. Numerous hydrogen bonds involving molecules of crystallization water link the layers into a three-dimensional framework. In III, the cationic and anionic complexes, which serve as proton donors and acceptors, respectively, are bound into layers parallel to the xy plane.     

Crystallographic investigations of 1,4-benzothiazin-2(1H)one and 3-methyl-1,4-benzothiazin-2(1H)one

The crystal structures of 1,4-benzothiazin-2(1H)one (C₈H₇SNO) (I) and 3-methyl-1,4-benzothiazin-2(1H)one (C₉H₉SNO) (II) have been determined by X-ray diffraction methods. I crystallizes in the monoclinic system with space group P2₁/n, while II crystallizes in triclinic with space group P $\bar 1$ . The molecular features in both the structures are almost similar; however, there exists an intermolecular interaction in (II) that could be due to the methyl group.     

Five-coordinate Co(II) complexes with nitrilotriacetic acid: Crystal structures of Ca[Co(Nta)X] · nH2O (X − = Cl, Br, or NCS)

The synthesis and X-ray diffraction study of three Ca[Co(Nta)X] · nH₂O complexes [X ^? = Cl, n = 2.3 (I); X ^? = Br, n = 2 (II); and X ^? = NCS, n = 2 (III)] are performed. The main structural units of crystals I–III are the [CoX(Nta)]^2? anionic complexes and hydrated Ca²⁺ cations. The anionic complexes have similar structures. The coordination of the Co²⁺ atom in the shape of a trigonal bipyramid is formed by N + 3O atoms of the Nta ^3? ligand and the X ^? anion in the trans position with respect to N. In structures I–III, the Co-O and Co-N bond lengths lie in the ranges 1.998–2.032 and 2.186–2.201 Å, respectively. The Co-X bond lengths are 2.294 (I), 2.436 and 2.445 (II), and 1.982 Å (III). The environments of the Ca²⁺ cations include oxygen atoms of one or two water molecules and six or seven O(Nta) atoms with the coordination number of 9 in I or 8 in II and III. The Ca-O(Nta) bonds form a three-dimensional framework in I or layers in II and III. Water molecules are involved in the hydrogen bonds O(w)-H···O(Nta), O(w)-H···X, and O(w)-H···O(w). Structural data for crystals I–III are deposited with the Cambridge Structural Database (CCDC nos. 287 814–287 816).     

Crystal structure of new complexes of praseodymium(III) nitrate and ytterbium(III) nitrate with 2,2′: 6,2′′-terpyridine

The crystal structure of new complexes of praseodymium(III) and ytterbium(III) (elements from the initial and final parts of the lanthanide series), namely, [Pr(NO₃)₃ (Terpy)((CH₃)₂CO)] (I) and [Yb(NO₃)₂(Terpy)(H₂O)₂]NO₃ · 2H₂O (II), is investigated. The structure of compound I consists of [Pr(NO₃)₃(Terpy)((CH₃)₂CO)] neutral complexes. The coordination number of the praseodymium atom is 10. The coordination polyhedron of the praseodymium atom can be described as a distorted bicapped tetragonal antiprism. The structure of compound II is composed of [Yb(NO₃)₂(Terpy)(H₂O)₂]⁺ cationic complexes, nitrate anions, and molecules of crystallization water. The structural components are joined together via a three-dimensional system of hydrogen bonds. The coordination polyhedron of the ytterbium atom can be represented as a distorted tricapped trigonal prism. The coordination number of the ytterbium atom is 9.     

Thermolysis of the tetrahedrane cluster PhCCo3(CO)3(μ-CO)Cp2 with the unsaturated diphosphine ligands (Z)-Ph2PCH=CHPPh2 and 4,5-Bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd): Redox properties and molecular structure of PhCCo3(CO)(μ-CO)[(Z)-Ph2PCH=CHPPh2]Cp2

Thermolysis of the tricobalt cluster PhCCo₃(CO)₃(μ-CO)Cp₂ (1) with the diphosphine ligands (Z)-Ph₂PCH=CHPPh₂ and 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) has been examined and found to give the diphosphine-substituted clusters PhCCo₃(CO)[(Z)-Ph₂PCH=CHPPh₂](μ-CO)Cp₂ (2) and PhCCo₃(CO)(bpcd)(μ-CO)Cp₂ (3) in moderate yield. The new compounds 2 and 3 have been isolated and characterized in solution by IR and NMR (¹H and ³¹P) spectroscopies. VT ³¹P NMR data reveal that the chelating diphosphine ligand is fluxional in solution and exhibits a rocking motion between the axial and equatorial sites that renders both phosphorus moieties identical at ambient temperature. The molecular structure of PhCCo₃(CO)[(Z)-Ph₂PCH=CHPPh₂](μ-CO)Cp₂ (2) has been determined by X-ray crystallography. PhCCo₃(CO)[(Z)-Ph₂PCH=CHPPh₂](μ-CO)Cp₂ crystallizes, as the CH₂Cl₂ solvate, in the monoclinic space P2₁/n, a = 16.822(2) Å, b = 10.554(1) Å, c = 23.135(3) Å, β = 100.944(2)^°, V = 4032.4(8) ų, Z = 4, and d _calc = 1.537 Mg/m³; R = 0.0488, R _w = 0.0725 for 9431 reflections with I > 2σ(I). The solid-state structure of cluster 2 establishes the chelating nature of the ancillary (Z)-Ph₂PCH=CHPPh₂ ligand at the unique Co(CO)P₂ center via coordination at an equatorial and an axial site. The redox behavior of clusters 2 and 3 has been explored by cyclic voltammetry and chronocoulometry. Each cluster reveals the presence of two one-electron oxidations of common origin due to the oxidation of a Co–Co bonding orbital. Whereas cluster 2 does not exhibit an accessible reduction process in CH₂Cl₂, a ligand-based one-electron reduction was found for cluster 3 given its low-lying π* LUMO associated with the bpcd ligand. The electrochemical data for clusters 2 and 3 are discussed with respect to the reported redox chemistry for this genre of tricobalt cluster and the bpcd ligand.     

Crystal structure of zinc(II) hydrated trinuclear complex with monoprotonated ethylenediaminetetraacetate anion(3−), [Zn<Subscript>3</Subscript>(H<Emphasis Type="Italic">Edta</Emphasis>)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>]

The crystal structure of the [Zn₃(HEdta)₂(H₂O)₆] complex (I) is determined by X-ray diffraction analysis. The crystals are orthorhombic, a = 14.780 Å, b = 29.699 Å, c = 7.032 Å, Z = 4, and space group Pna2₁. The structural units of crystals I are trinuclear linear molecules, in which the peripheral atoms Zn(1) and Zn(2) each coordinate two N atoms and three O atoms of the HEdta ^3? ligand and the O(w) atom of the H₂O molecule, whereas the central Zn(3) atom coordinates four O(w) atoms of the H₂O molecules and two terminal O atoms of the two HEdta ^3? ligands. The HEdta ^3? ligand fulfills a hexadentate chelating—bridging function. The bond lengths are as follows: Zn-O(HEdta), 2.006(4)–2.123(4) Å; Zn-N, 2.214(6) and 2.128(5) Å; and Zn-O(w), 2.006(6)–2.225(5) Å. In structure I, there is a specific contact formed by hydrogen bonds, owing to which the distance between the central atoms of individual molecules appears to be shorter than that in covalently bonded complexes.     

Synthesis and crystal structures of nitratocobaltates Na2[Co(NO3)4], K2[Co(NO3)4], and Ag[Co(NO3)3] and potassium nitratonickelate K2[Ni(NO3)4]

The cobalt(II) and nickel(II) nitrate complexes with an island structure (Na₂[Co(NO₃)₄] (I) and K₂[Co(NO₃)₄] (II)] and a chain structure [Ag[Co(NO₃)₃] (III) and K₂[Ni(NO₃)₄] (IV)] are synthesized and investigated using X-ray diffraction. In the anionic complex [Co(NO₃)₄]^2? of the crystal structure of compound I, the Co coordination polyhedron is a twisted tetragonal prism formed by the O atoms of four asymmetric bidentate nitrate groups. In the anion [Co(NO₃)₄]^2? of the crystal structure of compound II, one of the four NO₃ groups is monodentate and the other NO₃ groups are bidentate (the coordination number of the cobalt atom is equal to seven, and the cobalt coordination polyhedron is a monocapped trigonal prism). The crystal structures of compounds III and IV contain infinite chains of the compositions [Co(NO₃)₂(NO₃)_2/2]^? and [Ni(NO₃)₃(NO₃)_2/2]^2?, respectively. In the crystal structure of compound III, seven oxygen atoms of one monodentate and three bidentate nitrate groups form a dodecahedron with an unoccupied vertex of the A type around the Co atom. In the crystal structure of compound IV, the octahedral polyhedron of the Ni atom is formed by five nitrate groups, one of which is terminal bidentate. The data on the structure of Co(II) coordination polyhedra in the known nitratocobaltates are generalized.     

Crystal structure of strontium Di[bis(iminodiacetato)cobaltate(III)] pentahydrate,Sr[<Emphasis Type="Italic">cis</Emphasis>(N)-Co(<Emphasis Type="Italic">Ida</Emphasis>)<Subscript>2</Subscript>]<Subscript>2</Subscript> · 5H<Subscript>2</Subscript>O

Compound Sr[cis(N)-Co(Ida)₂]₂ · 5H₂O (I) is synthesized and its crystal structure is determined. The crystals are built of [Co(Ida)₂]^? anionic complexes, [Sr(H₂O)₃]²⁺ hydrated cations, and crystallization water molecules. Two independent anions are located on rotation axis 2 and have close structures. A distorted octahedral coordination of Co³⁺ atoms is formed by two N atoms and four O atoms of two Ida ^2? ligands [Co-N, 1.932(3) and 1.940(3) Å; Co-O, 1.879–1.899(3) Å]. [Sr(H₂O)₃]²⁺ cations randomly occupy half of the positions in the vicinity of centers of inversion. In addition to three water molecules, the environment of the Sr²⁺ atom includes five O atoms of five Ida ^2? ligands [Sr-O, 2.487(3)-2.889(5) Å]. Because of the disordering of [Sr(H₂O)₃]²⁺ cations, the structural function of the Ida ^2- ligands varies from tridentate chelate to pentadentate bridging chelate. Sr-O and hydrogen bonds connect structural elements into a three-dimensional framework. The structure of I is compared with that of a related compound Sr[CoEdta]₂·9H₂O (II). It is shown that the formation of N-H…O hydrogen bonds, which connect [Co(Ida)₂]^? anionic complexes in I into compact chains, is an important factor leading to the difference between packings I and II.     

Molecular and crystal structures of p-heptyloxyphenyl p-hexyloxybenzoate and p-butyloxyphenyl p-heptyloxybenzoate: Mesophase design

Two aromatic esters with the formulas C₆H₁₃-O-C₆H₄-C(O)O-C₆H₄-O-C₇H₁₅ (1) and C₇H₁₅-O-C₆H₄-C(O)O-C₆H₄-O-C₄H₉ (2) belonging to nematic liquid-crystal compounds were studied by X-ray diffraction. Compound 1 crystallizes in two modifications: monoclinic (1-m) and triclinic (1-tr). The crystal packing of 1 and 2 is built from alternating loosely packed aliphatic regions and closely packed aromatic regions. In crystal structures 1-m and 2, the aromatic regions are linked into chains by hydrogen bonds with the participation of the carbonyl oxygen atom of the ester group and the C-H fragment of the benzene ring, but these hydrogen bonds in 1-m are much weaker than in 2. In 1-m there are π-stacking interactions between the molecules, resulting in the formation of centrosymmetric dimers with an interplanar distance of 3.45 Å. In 1-tr, the aromatic fragments form a herringbone packing motif favorable for a two-dimensional network of directional C-H...π-system interactions.     

Synthesis and structure of zirconium and 3d-transition metal phosphates M 0.5Zr2(PO4)3(M = Mn, Co, Ni, Cu, Zn)

Double zirconium and 3d-transition metal phosphates of the compositions M 0.5Zr2(PO4)3[M = Mn (I), Co (II), Ni (III), Cu (IV), Zn (V)] have been synthesized and the types of their structures have been refined. Compounds I, II, III, IV, and V are all monoclinic (sp. gr. P2₁/n, Z = 4) and have the unit cell parameters a = 12.390(3), 12.389(3), 12.385(3), 12.389(3), 12.389(2) Å; b = 8.931(4), 8.928(3), 8.924(4), 8.925(4), 8.929(3) Å; c = 8.843(3), 8.840(2), 8.840(3), 8.841(3), 8.842(2) Å, β = 90.55(1), 90.54(1), 90.53(1), 90.53(1), 90.54(1)°; V = 978.5, 977.7, 977.0, 977.4, 978.1 ų, respectively. All the structures have the {[Zr₂(PO₄)₃]^?}3_∞-type frameworks. The crystallographic data for 3d-transition and alkali earth metal phosphates described by the general formula M _0.5Zr₂(PO₄)₃ are compared.     

X-Ray diffraction and IR-spectroscopic studies of UO2(n-C3H7COO)2(H2O)2 and Mg(H2O)6[UO2(n-C3H7COO)3]2

Single crystals of UO₂(n-C₃H₇COO)₂(H₂O)₂ (I) and Mg(H₂O)₆[UO₂(n-C₃H₇COO)₃]₂ (II) are synthesized. Their IR-spectroscopic and X-ray diffraction studies are performed. Crystals I are monoclinic, a = 9.8124(7) Å, b = 19.2394(14) Å, c = 12.9251(11) Å, β = 122.423(1)°, space group P2₁/c, Z = 6, and R = 0.0268. Crystals II are cubic, a = 15.6935(6) Å, space group $Pa\bar 3$ , Z = 4, and R = 0.0173. The main structural units of I and II are [UO₂(C₃H₇COO)₂(H₂O)₂] molecules and [UO₂(C₃H₇COO)₃]^? anionic complexes, respectively, which belong to AB ₂ ⁰¹ M ₂ ¹ (I) and AB ₃ ⁰¹ (II) crystal chemical groups of uranyl complexes (A = UO ₂ ²⁺ , B ⁰¹ = C₃H₇COO^?, and M ¹ = H₂O). A crystal chemical analysis of UO₂ L ₂ · nH₂O compounds, where L is a carboxylate ion, is performed.