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Abstract Crystals of (2.2.2-cryptand)potassium bromide hydrate of composition 2 : 7, [K(Crypt-222)]+Br- · 3.5H2O (I), are synthesized and studied by X-ray diffraction analysis. The crystals are trigonal, space group P , a = 11.858(2) Å, c = 11.370(2) Å, Z = 2. The structure is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.098 against 2668 independent reflections (CAD4 automated diffractometer, ?MoKa radiation). Structure I contains complex cation [K(Crypt-222)]+ of the host-guest type arranged in crystallographic axis 3 with approximate symmetry D3. The coordination polyhedron of the K+ cation is a two-base-centered trigonal prism somewhat distorted to form antiprism. In crystal I, bromide anions and water molecules are linked by hydrogen bonds to form an infinite chain of alternating Br- anions multiplied by integer translations along axis z and disordered cubes of water molecules and other Br- anions. [ABSTRACT FROM AUTHOR]

Abstract The crystal and molecular structures of (trans-3,4-diamino-2,2,6,6-tetramethylpiperidine-1-oxyl-N3, N4)(oxalato-O,O')platinum(II) (C11H20N3O5Pt) are studied by X-ray diffraction analysis. The crystals are monoclinic: a=15.210 Å, b=7.222 Å, c=14.520 Å, ß=118.14°, Z=4, and space group P21/c. The structure is solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R=0.05 against 3227 independent reflections (CAD4 automated diffractometer, ?MoKa). A molecule of the complex is mononuclear with two different bidentate ligands. The coordination of the Pt2+ cation is a distorted square. The crystal contains intermolecular hydrogen bonds. [ABSTRACT FROM AUTHOR]

The salt tetrakis(isothiocyanato)zinc(II) 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane, [H2(Crypt-222)]2+ · [Zn(NCS)4]2– (I), was synthesized and its structure was determined using X-ray diffraction analysis: space group P21/n, a = 13.734 Å, b = 11.627 Å, c = 20.816 Å, β = 91.51°, Z = 4. The structure was solved by direct methods and anisotropically refined by the full-matrix least-squares method to R =0.093 for 4920 independent reflections (CAD4 autodiffractometer, λCuKα radiation). The structural units of crystal I are 2.2.2-cryptand dications (with two protonated nitrogen atoms) and complex anions [Zn(NCS)4]2–. The coordination polyhedron of the Zn2+ cation is a distorted tetrahedron. The 2.2.2-cryptand dication contains trifurcate N–H(…O)3 hydrogen bonds. [ABSTRACT FROM AUTHOR]

Absract—Diaqua(2.2.2-Cryptand)strontium dichloride trihydrate [Sr(2.2.2-Crypt)(H2O)2]2+ · 2Cl– · 3H2O (I) was prepared and studied by X-ray diffraction. The triclinic structure of I (space group P/math>, a = 9.152 Å, b = 10.140 Å, c = 15.219 Å, α = 88.84°, β = 88.19°, γ = 87.62°, Z = 2) was solved by the direct method and refined by full-matrix least-squares calculations in the anisotropic approximation to R = 0.050 for 4188 independent reflections (CAD4 automated diffractometer, λCuKα radiation). The structure contains the [Sr(2.2.2-Crypt)(H2O)2]2+ host–guest cation. The Sr2+ cation resides in the 2.2.2-cryptand cavity and is coordinated by all eight heteroatoms (6O + 2N) of the cryptand ligand and by two O atoms of water molecules. The Sr2+ coordination polyhedron (C.N. 10) is a highly distorted dibase-centered two-cap trigonal prism. The crystal structure of I contains a branched system of ion–ion (intermolecular) hydrogen bonds O(w)–H···Cl–, which connect the complex cations, the Cl– anions, and the crystal water molecules to form infinite thick layers parallel to the yz plane. [ABSTRACT FROM AUTHOR]

The reaction of quinoxaline-2-carbaldehyde with ethyl (E)-3-aminocrotonate afforded ethyl 4-oxo-1,4-dihydropyrido[2,3-b]quinoxaline-3-carboxylate, which is a structural analog of nalidixic and 4-quinolone-3-carboxylic acids representing the basis of the known antibacterial drugs of the fluoroquinolone series. [ABSTRACT FROM AUTHOR]

Crystalline bis(dibenzo-18-crown-6)rubidium triiodide complex [Rb(DB18C6)2]+ · I3– (I) is synthesized and its structure is studied by X-ray diffraction analysis. The structure of I (space group Pnma, a = 23.854 Å, b = 23.612 Å, c = 7.863 Å, Z = 4) is solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.079 against 3990 independent reflections (CAD4 automated diffractometer, ?MoKa). Structural units of crystal I are the I3– anions and [Rb(DB18C6)2]+ cations. The crystal has the structure intermediate between that of a standard host–guest complex and a sandwich complex. In the structure of complex I, the crystallographic plane with symmetry m passes through the I3– anion (perpendicularly to its axis) and complex cation. The coordination polyhedron of the Rb+ cation is a strongly distorted hexagonal pyramid with the O atom of one crown ligand at the axial vertex and a base of six O atoms of another DB18C6 crown ligand. [ABSTRACT FROM AUTHOR]

The crystals of the hydrated complex of a podand 1,2-bis(2-(o-hydroxyphenoxy)ethoxy)ethane (L) with sodium thiocyanate of the composition [Na(NCS)L(H2O)] (I) were prepared and studied by X-ray diffraction analysis. The structure of I (space group P21/n, a = 12.128 Å, b = 14.221 Å, c = 13.594 Å, β = 113.82°, Z = 4) was solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.055 over all 2970 independent reflections (CAD4 automated diffractometer, λMoKα radiation). The individual host–guest type molecules are connected in crystal I by hydrogen bonds. The coordination polyhedron of the Na+ cation is a distorted pentagonal bipyramid whose base consists of five O atoms of the podand L and whose axial positions are occupied by the O atom of water and the N atom of SCN–. The sixth O atom of the podand L is not involved in Na+ coordination. [ABSTRACT FROM AUTHOR]

(2.2.2-Cryptand)lithium perchlorate [Li(2.2.2-Crypt)]+ClO–4 (I) is prepared and characterized by X-ray structural analysis. Structure I (space group P21212, a = 10.149 Å, b = 13.475 Å, c = 8.580 Å, Z = 2) is solved by the direct method and refined anisotropically by the full-matrix least-squares method to R = 0.056 for 2312 reflections (CAD4 automated diffractometer, λMoKα). Crystal of complex I is built of [Li(2.2.2-Crypt)]+ complex cations of the host–guest type and randomly disordered ClO–4 anions. Both ions are located on the twofold crystallographic axes. The Li+ cation, which is also randomly disordered about the 2 axis, is coordinated by the N atom and five O atoms from eight heteroatoms (2N + 6O) of the cryptand. Two Li–O and one Li–N bonds are noticeably elongated. The Li+ cation forms irregular six-vertex coordination polyhedron. [ABSTRACT FROM AUTHOR]

The crystal adduct (1 :1) 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane triaquachlorolithium dichloride, [H2(Crypt-222)]2+ · 2Cl– · [LiCl(H2O)3] (I), was synthesized and studied using X-ray diffraction analysis. Structure I (space group R3, a = 7.922 Å, c = 37.207 Å, Z = 3) was solved by direct methods and anisotropically refined by the full-matrix least-squares method to R = 0.034 for 1363 independent reflections (CAD4 autodiffractometer, λMoKα). Crystal I consists of disordered 2.2.2-cryptand dications, chloride anions, and tetrahedral [LiCl(H2O)3] complexes. All of them lie on threefold axes. There are tridentate +N–H (···O)3 hydrogen bonds in the [H2(Crypt-222)]2+ dication. The crystal structure of adduct I contains a complex interionic hydrogen bonding system. [ABSTRACT FROM AUTHOR]

The aqua complex of podand 1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane (L) with strontium perchlorate of the composition [Sr(ClO4)L(H2O)2]+ · ClO4– · H2O (I) was synthesized and studied using X-ray diffraction analysis: space group P21/c, a = 16.195 Å, b = 11.382 Å, c = 16.646 Å, ß = 117.01°, Z = 4. The structure was solved by direct method and anisotropically refined by the full-matrix least-squares method to R = 0.069 for 4278 independent reflections (CAD4 autodiffractometer, ?MoKa). Structure I contains complex cation [Sr(ClO4)L(H2O)2]+ of the host–guest type. The Sr2+ cation (coordination number 9) is coordinated to all six O atoms of the L podand, O atom of a disordered ClO4– ligand, and two O atoms of two water molecules. The coordination polyhedron of Sr2+ is irregular; in a rough approximation, it can be described as a face-centered cube. The crystal structure of I contains an infinite three-dimensional network of the O–H···O hydrogen bonds joining the complex cations, ClO4– anions, and molecules of crystallization water. [ABSTRACT FROM AUTHOR]

The aqua complex of podand 1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane (L) with strontium perchlorate of the composition [Sr(ClO4)L(H2O)2]+ · ClO4– · H2O (I) was synthesized and studied using X-ray diffraction analysis: space group P21/c, a = 16.195 Å, b = 11.382 Å, c = 16.646 Å, β = 117.01°, Z = 4. The structure was solved by direct method and anisotropically refined by the full-matrix least-squares method to R = 0.069 for 4278 independent reflections (CAD4 autodiffractometer, λMoKα). Structure I contains complex cation [Sr(ClO4)L(H2O)2]+ of the host–guest type. The Sr2+ cation (coordination number 9) is coordinated to all six O atoms of the L podand, O atom of a disordered ClO4– ligand, and two O atoms of two water molecules. The coordination polyhedron of Sr2+ is irregular; in a rough approximation, it can be described as a face-centered cube. The crystal structure of I contains an infinite three-dimensional network of the O–H···O hydrogen bonds joining the complex cations, ClO4– anions, and molecules of crystallization water. [ABSTRACT FROM AUTHOR]

The aqua complex of podand 1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane (L) with strontium thiocyanate of the composition [Sr(NCS)L(H2O)2]+ · SCN– (I), was synthesized and studied by X-ray diffraction analysis: space group P 21/c, a = 17.730 Å, b = 8.558 Å, c = 18.169 Å, β = 116.15°, Z = 4. The structure was solved by direct method and anisotropically refined by the full-matrix least-squares method to R = 0.039 for 4333 independent reflections (CAD4 autodiffractometer, λMoKα). Structure I contains complex cation [Sr(NCS)L(H2O)2]+ of the host–guest type. The coordination polyhedron of Sr2+ cation (coordination number 9) is a distorted pentagonal bipyramid with four oxygen atoms at the benzene rings of the L podand and the oxygen atom of one water molecule in its base, the N atom of the SCN– ligand at its single vertex, and with the remaining two O atoms of the L podand and O atom of another water molecule at a “triple vertex.” In a crystal, the complex cations and SCN– anions are joined through the hydrogen bonds to form bulky layers parallel to the xy plane. [ABSTRACT FROM AUTHOR]

Complex of podand 1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane (L) with potassium thiocyanate, [K2(NCS)2L2] (I) was synthesized and studied using X-ray diffraction analysis: space group P/math>, a = 7.771 Å, b = 11.711 Å, c = 11.965 Å, α = 72.22°, β = 79.21°, γ = 89.07°, Z = 1. Structure I was solved by direct method and anisotropically refined by the full-matrix least-squares method to R = 0.040 for all 4370 independent reflections (CAD4 autodiffractometer, λMoKα). Structure I contains [K(NCS)L] monomers of the host–guest type united into centrosymmetrical [K2(NCS)2L2] dimers via two bridging OH groups (one group from two L podands). In the monomer, the L podand appears as though to envelope the octacoordinated K+ cation, whose the coordination polyhedron is a strongly distorted hexagonal bipyramid with all six oxygen atoms of the L podand in its base and the N atom of the SCN– ligand and the O atom of one of OH group of the neighboring (in dimer) L podand at its axial vertices. Molecules of I in crystal are joined through the O–H···N hydrogen bonds to form broad infinite chains along the x-axis. [ABSTRACT FROM AUTHOR]