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Abraham Clearfield

Publications and source records attributed to Abraham Clearfield.

At least 19 recordsLinked to original sources
PubMed2005

Novel chiral "calixsalen" macrocycle and chiral robson-type macrocyclic complexes.

A family of novel chiral "calixsalen" Schiff base macrocycles R,R-H(3)L4, R,R-H(3)L5, containing three chiral diamino moieties were synthesized by an efficient self-assembly and characterized by (1)H and (13)C NMR, mass spectrometry, and X-ray diffraction. The systematic synthesis, structure, and coordination properties of the [2 + 2] and [3 + 3] Robson-type Schiff base macrocyclic mono-, di-, tri-, and tetranuclear metal complexes were explored.

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PubMed2004

DOTP-manganese and -nickel complexes: from a tetrahedral network with 12-membered rings to an ionic phosphonate.

DOTP (1,4,7,10-tetrakis(methylenephosphonic acid)-1,4,7,10-tetraazacyclododecane) was reacted hydrothermally with MnCl(2).2H(2)O and Ni(NO(3))(2).6H(2)O resulting in two structurally different compounds. Mn[C(3)NH(7)(PO(3)H(0.5))](4) crystallizes in the tetragonal space group P4/ncc, with a = 12.349(2) A, b = 12.349(2) A, c = 14.066(4) A, V = 2144.9(8) A(3), and Z = 4. Manganese atoms are tetrahedrally bonded by four phosphonate oxygen atoms from four equivalent ligands. All 12-membered macrocycles are connected in a "zigzag" manner by sharing manganese atoms and forming 22-membered cavities between each pair of two adjacent macrocycles. Ni[C(3)NH(6)(PO(3)H)](4)[Ni(H(2)O)(6)] crystallizes as an ion pair complex. Ni(1) is octahedrally coordinated to two pendent phosphonate oxygen atoms and four nitrogen atoms from the macrocyclic backbone. Ni(2) is surrounded by six coordinatedly bonded water molecules to form a hexaqua cation. The manganese complex shows ion exchange capability for Cs(+).

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PubMed2004

Synthesis and characterization of a new bisphosphonic acid and several metal hybrids derivatives.

Commercial bis-(4-bromophenyl)-ether, [BrC(6)H(4)](2)-O, has been used to prepare 4-[4'-(diethoxyphosphoryl)phenoxy]phenyl-phosphonic acid diethyl ester, [(CH(3)CH(2))(2)O(3)P-C(6)H(4)](2)-O, (I) following a slight modification of the Michaelis-Arbuzov reaction. The acid hydrolysis of I gave 4-(4'-phosphonophenoxy)phenyl phosphonic acid, [H(2)O(3)P-C(6)H(4)](2)-O (II), and both compounds have been characterized by (1)H NMR and (13)C NMR. The crystal structure of II has been determined by single-crystal X-ray diffraction. II crystallizes in an orthorhombic unit cell, space group Pbcn, with a = 7.822(3) A, b = 5.821(2) A, c = 28.982(9) A, and V = 1319.7(7) A(3). The final R factor was R1 = 0.0614. The structure is layered, being held together through a hydrogen bonding network. II has been used as precursor in the syntheses of new metal (Mn, Fe, Co, Ni, Cu, and Zn) bisphosphonates. The syntheses were carried out using a fixed metal/bisphosphonic acid molar ratio of 2.1:1 and the influence of the pH in the reactions has been studied. Nine new compounds have been isolated: Mn(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)).1.5H(2)O (III), Mn(5)(OH)(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3))(2).2H(2)O (IV), Fe(HO(3)PC(6)H(4)OC(6)H(4)PO(3)).0.5H(2)O (V), Co(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)).2H(2)O (VI), Ni(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)).3H(2)O (VII), Ni(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)).2H(2)O (VIII), Cu(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)) (IX), Zn(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)) (X), and Zn(HO(3)PC(6)H(4)OC(6)H(4)PO(3)H) (XI). Compound IX crystallizes in an orthorhombic unit cell, space group Pbcn, and unit cell parameters a = 8.1012(5) A, b = 5.3109(3) A, c = 29.2595(5) A, and V = 1258.8(1) A(3). Its structure has been solved by ab initio powder diffraction and refined by the Rietveld method to R(F) = 0.042. IX has a pillared layer framework with highly distorted CuO(5) groups sharing edges to give isolated dimers. XI was indexed in a monoclinic unit cell, space group P112(1), with parameters a = 9.4991(9) A, b = 5.0445(5) A, c = 29.131(2) A, gamma = 91.945(7) degrees, and V = 1395.1(3) A(3). Its structure has been refined by the Rietveld method, R(F) = 0.054, since it is isostructural with the known compound, Zn[HO(3)P(C(6)H(4))(2)PO(3)H]. All solids were also characterized by thermal analysis and IR and UV-Vis spectroscopies.

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PubMed2004

A novel cadmium aminophosphonate: X-ray powder diffraction structure, solid-state IR and NMR spectroscopic determination of the fine structure of the organic moieties.

A new divalent cadmium phosphonate, Cd2Cl2(H2O)4(H2L), has been synthesized from the ethylenediamine-N,N'-bis(methylenephosphonic acid) (H4L). The obtained microcrystalline compound has been characterized by solid-state IR spectra and 13C, 31P, and 113Cd CP MAS NMR. The static 13P NMR spectra have been also recorded to give the delta11, delta22, and delta33 chemical shift parameters for both compounds. The spectral data, collected for Cd2Cl2(H2O)4(H2L), are in an agreement with its X-ray powder diffraction structure solved with the cell dimensions a = 16.6105(10), b = 7.1572(4), and c = 6.8171(4) A and beta = 98.327(4) degrees. The octahedral coordination sphere of the cadmium atoms consists of two phosphonate oxygen atoms, two water oxygen atoms, and the two chlorine atoms. Cadmium atoms are bridged by the chlorine atoms forming four-membered rings. The phosphorus atoms exhibit a tetrahedral coordination with two oxygen atoms bonded to the cadmium atoms with P-O distances of 1.503(10) and 1.504(10) A. The third oxygen atom, showing a longer P-O distance (1.546(9) A), is not bonded to the metal center, nor is it bonded to a proton. The combined IR and NMR proton-phosphorus cross-polarization kinetic data together with the X-ray data confirm that the cadmium phosphonate has the zwitterionic structure (NH2(+)CH2P(O2Cd2)O-) similar to the initial aminophosphonic acid H4L.

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PubMed2004

Synthesis, characterization, and crystal structures of three new divalent metal carboxylate-sulfonates with a layered and one-dimensional structure.

Hydrothermal reactions of 5-sulfoisophthalic acid (HO(3)SC(6)H(3)-1,3-(CO(2)H)(2), H(3)L) with M(II) carbonate (or oxide) and 4,4'-bipyridine (4,4'-bipy) (or 2,2'-bipyridine, 2,2'-bipy) resulted in three new metal carboxylate-sulfonate hybrids, namely, [CdL(H-4,4'-bipy)] (1) and [Cd(3)L(2)(2,2-bipy)(4)(H(2)O)(2)].2H(2)O (2) with layered structures and [ZnL(H-4,4'-bipy)(H(2)O)].2H(2)O (3), whose structure features a one-dimensional double chain. The cadmium(II) ion in complex 1 is seven-coordinated by five carboxylate oxygen atoms and one sulfonate oxygen atom from four ligands and a unidentate 4,4'-bipyridine. The interconnection of the cadmium(II) ions through bridging carboxylate-sulfonate ligands resulted in the formation of a <002> double layer with the bipyridyl rings orientated toward the interlayer space. Complex 2 has a different layered structure. Cd(1) is seven-coordinated by two bidentate chelating carboxylate groups from two ligands, a bidentate chelating 2,2'-bipy and an aqua ligand, and Cd(2) is octahedrally coordinated by two bidentate chelating 2,2'-bipy's, a sulfonate oxygen, and an aqua ligand. The coordination geometry around Cd(3) is similar to that of Cd(1) with the aqua ligand being replaced by an oxygen atom from the sulfonate group. The carboxylate-sulfonate ligand acts as pentadentate ligand, bridging with three cadmium(II) ions. The bridging of cadmium(II) ions through the carboxylate-sulfonate ligands resulted in the formation of <006> and <003> layers; the 2,2'-bipy molecules and [Cd(2)(2,2'-bipy)(2)(H(2)O)] cations are orientated to the interlayer space. Complex 3 features a 1D metal carboxylate-sulfonate double chain along the diagonal of the a- and b-axes. The zinc(II) ion is octahedrally coordinated by four carboxylate O atoms from three ligands, a unidentate 4,4'-bipy, and an aqua ligand. Each pair of zinc(II) ions is bridged by two carboxylate groups from two ligands to form a dimer, and such dimeric units are interconnected by bridging ligands to form a double chain. The sulfonate group of the carboxylate sulfonate ligand remains noncoordinated and forms a number of hydrogen bonds with aqua ligands as well as lattice water molecules.

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PubMed2003

Magnetic property studies of manganese-phosphate complexes.

Phosphoric acid forms two distinct coordination compounds with manganese salts in aqueous media, a two-dimensional layered structure, [Mn(HPO4).(H2O)3], 1, under ambient conditions, and a three-dimensional synthetic mineral, [Mn5(mu-OH2)2(HPO4)2(PO4)2(H2O)2], 2, under hydrothermal procedures, at 120 degrees C. In compound 1, the oxygen atom of the doubly deprotonated phosphoric acid interconnects the metal centers to form a layered structure. The neutral hydrophilic layers of 1 are separated by 5.5 A and may potentially intercalate hydrophilic organic guest molecules. The metal centers in 2 are octahedral and bridged by PO4(3-), HPO4(2-), and OH2 groups to form a complex three-dimensional network. XPS analysis on 1 and 2 confirms that manganese exists in the +2 oxidation state. Compound 2 is a poor ion exchanger, but some improvement is observed on partial dehydration. The magnetic properties of both 1 and 2 were studied in detail to examine the amplitude of the magnetic interactions through phosphate ligand bridges. While 1 reveals dominant antiferromagnetic interactions between the spin carriers, a complete investigation of the magnetic properties of 2 revealed its true nature to be a glassy magnet.

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PubMed2003

Cobalt phosphonates: an unusual polymeric cobalt phosphonate containing a clathrated phosphonate anion and a layered bisphosphonate.

Novel cobalt phosphonates [Co(H(2)O)(4)(H(4)L)][H(2)L].2H(2)O, 1, and Co(2)(H(2)O)(2)(L), 2, have been synthesized from 1,8-octylenediphosphonic acid (H(4)L). 1 has been fully characterized by X-ray single-crystal data, TGA, IR spectroscopy, and chemical analysis. The compound crystallizes in the triclinic space group P1 with a = 5.5415(8) A, b = 8.6382(8) A, c = 16.794 (2) A, alpha = 87.694(2) degrees, beta = 80.859(2) degrees, gamma = 76.005(2) degrees, V = 770.11(19) A(3), and Z = 1. A cobalt atom lies in the center of symmetry and is octahedrally coordinated by two oxygen atoms from two undissociated diphosphonic ligands H(4)L and four molecules of water. The cobalt atom and undissociated ligand H(4)L are combined to form polymeric chains along the c-axis, resulting in the formation of a one-dimensional framework. The positive charge on the cobalt atom remains upon coordination and is balanced by a negatively charged uncoordinated ligand (H(2)L) found as a clathrate in the lattice. Two lattice water molecules, hydrogen-bonded with the coordinated and uncoordinated ligands, complete the structure. The metal phosphonate chains are held together and bridge the uncoordinated anionic ligands by a number of strong hydrogen bonds, which make the structure possible. Cobalt phosphonate 2 has been characterized by TGA measurements, IR spectroscopy, and chemical analysis. The compound has a layered structure with an interlayer spacing of 14.26 A. Metal phosphonate layers are cross-linked by hydrocarbon chains. The water molecules are coordinated to the metal atom. According to IR data, compound 2 contains two equivalent PO bonds and one different PO bond, which may be a result of the different types of Co-O-P connectivity within one phosphonic group.

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PubMed2003

[Zn6[MeN(CH2CO2)(CH2PO3)](6)(Zn)]4- anion: the first example of the oxo-bridged Zn6 octahedron with a centered Zn(II) cation.

Hydrothermal reactions of N-(phosphonomethyl)-N-methylglycine, MeN(CH(2)CO(2)H)(CH(2)PO(3)H(2)) (H(3)L), with zinc(II) acetate resulted in the formation of a novel zinc carboxylate-phosphonate, [Zn(6)L(6)(Zn)][Zn(H(2)O)(6)](2) x 22H(2)O (1). The structure of 1 contains a heptanuclear zinc phosphonate cluster anion, [Zn(6)L(6)(Zn)](4-), in which seven zinc(II) cations form an unusual Zn(6)(Zn) centered octahedron with six of its Zn(3) triangle faces each further capped by a phosphonate group. The Zn(II) cations of the Zn(6) octahedron are five-coordinated whereas the centered Zn(II) cation is octahedrally coordinated. Packing of these cluster anions creates micropores occupied by the hydrated zinc(II) cations as well as lattice water molecules. The structural skeleton of 1 is retained after the removal of the lattice water molecules.

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PubMed2003

The first framework solid composed of vanadosilicate clusters.

In this Communication, we report the first example of a network structure composed of vanadosilicate clusters. We utilized hydrothermal conditions to synthesize a polyoxovanadogermanate (POVG): (C4H14N2)4[V14O44(GeOH)8].6H2O. By substituting SiO2 for GeO2 in the synthesis, a framework solid, H4V18O46(SiO)8C4H12N2)4.(H2O)] .4H2O, is formed in which isostructural vanadosilicate clusters are linked by five-coordinate vanadium with a (VO)O2N2 environment. The charge-compensating organic amine, 1,4-diaminobutane, in the POVG is covalently bonded to the linking vanadium polyhedra in the framework solid.

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PubMed2003

Sulfonated microporous organic-inorganic hybrids as strong Bronsted acids.

It has been discovered that the use of excess zirconium in reactions with 4,4'-biphenyl and 4,4'-terphenylbis(phosphonic acid) in DMSO or DMSO-ethanol mixtures produces microporous inorganic-organic hybrids. Surface areas of 400 m(2)/g and pore sizes in the range of 10-20 A in diameter are routinely obtained. These materials are readily sulfonated with SO(3) under pressure to yield strong Bronsted acids. The acid strength, measured by (13)C NMR shifts of acetone and cyclopentanone in contact with the sulfonates, indicates an acidity close to that of 100% H(2)SO(4). Condensation and cracking reactions were obtained for both ketones under mild conditions. A working hypothesis is presented to account for the high surface area and microporosity. The combination of high surface areas and pore dimensions that are between those of zeolites and mesoporous silicas commends these materials for applications in separations, ion exchange, and catalysis.

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PubMed2002

New lead inorganic-organic hybrid microporous and layered materials: synthesis, properties, and crystal structures.

Two new lead(II) phosphonates, namely, Pb2[PMIDA]*1.5H2O (1) (H4PMIDA = H2O3PCH2N(CH2CO2H)2) and Pb(H2L) (2) (H4L = CH3N(CH2PO3H2)2), have been synthesized by hydrothermal reactions at 150 degrees C. Complex 1 crystallized in tetragonal P42/n with cell dimensions of a = 17.317(7) and c = 7.507(5) A and Z = 8. In complex 1, Pb(1) is 6-coordinated by chelation in a tetradentate fashion by a PMIDA ligand (3 O, 1 N) and two phosphonate oxygen atoms from neighboring Pb(PMIDA) units in a severely distorted octahedral geometry, whereas Pb(2) is 6-coordinated by 4 carboxylate and 2 phosphonate oxygen atoms also with a severely distorted octahedral environment. These two different types of Pb(II) ions are interconnected through bridging carboxylate and phosphonate groups, resulting in a 3D network with micropores, whose cavity is filled by lattice water molecules interlinked via hydrogen bonds. Each PMIDA ligand bridges with 8 Pb(II) ions (3 Pb(1) and 5 Pb(2)). Complex 2 is orthorhombic, P2(1)2(1)2(1), with a = 7.382(5), b = 7.440(6), and c = 30.75(2) A and Z = 8. The structure of 2 features a 2D double lead(II) phosphonate layer along the ab plane. Each lead(II) ion is 5-coordinated by five phosphonate oxygen atoms from four ligands in a distorted trigonal bipyramid geometry. These double layers are further interconnected via hydrogen bonds between the protonated and uncoordinated phosphonate oxygens along the c-axis.

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PubMed2002

Synthesis, characterization, and crystal structures of two new divalent metal complexes of N,N'-bis(phosphonomethyl)-1,10-diaza-18-crown-6: a hydrogen-bonded 1D array and a 3D network with a large channel.

Reaction of N,N'-bis(phosphonomethyl)-1,10-diaza-18-crown-6 (H(4)L) with copper(II) acetate in 1:1 ethanol/water mixed solvents afforded a new crystal-engineered supramolecular metal phosphonate, Cu(H(2)L) (complex 1). By reaction of the same ligand with cadmium(II) nitrate in a 2:1 (M/L) ratio in methanol, a cadmium(II) complex with a 3D network structure was isolated, Cd(2.75)(L)(H(2)O)(7) x 1.5NO(3) x 7H(2)O x MeOH (complex 2). The copper(II) complex crystallized in the monoclinic space group P2(1)/c, with a =10.125(4), b = 14.103(6), and c = 14.537(6) A, beta = 91.049(8) degrees, V = 2075.4(16) A(3), and Z = 2. The Cu(II) ions in complex 1 are 6-coordinated by two phosphonate oxygen atoms, two nitrogen, and two oxygen atoms from the crown ether ring. Their coordination geometry can be described as Jahn-Teller-distorted octahedral, with elongated Cu-O(crown) distances (2.634(4) and 2.671(4) A for Cu(1) and Cu(2), respectively). The other two crown oxygen atoms remain uncoordinated. Neighboring two Cu(H(2)L) units are further interlinked via a pair of strong hydrogen bonds between uncoordinated phosphonate oxygen atoms, resulting in a one-dimensional supramolecular array along the a axis. The cadmium(II) complex is tetragonal, P4(2)/n (No. 86) with a = 20.8150(9) and c = 18.5846(12) A, V = 8052.0(7) A(3), and Z = 8. Among four cadmium(II) atoms in an asymmetric unit, one is 8-coordinated by four chelating phosphonate groups, the second one is 8-coordinated by 6 coordination atoms from a crown ring and two oxygen atoms from two phosphonate groups, the third Cd(II) atom is octahedrally coordinated by three aqua ligands and three phosphonate oxygen atoms from three phosphonate groups, and the fourth one is 6-coordinated by four aqua ligands and two oxygen atoms from two phosphonate groups in a distorted octahedral geometry. These cadmium atoms are interconnected by bridging phosphonate tetrahedra in such a way as to form large channels along the c direction, in which the lattice water molecules, methanol solvent, and nitrate anions reside. The effect of extent of deprotonation of phosphonic acids on the type of complex formed is also discussed.

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PubMed2002

Complexes formed between nitrilotris(methylenephosphonic acid) and M(2+) transition metals: isostructural organic-inorganic hybrids.

Nitrilotris(methylenephosphonic acid) (NTP, [N(CH(2)PO(3)H(2))(3)]) recently has been found to form three-dimensional porous structures with encapsulation of templates as well as layered and linear structures with template intercalation. It was, therefore, of interest to examine the type of organic-inorganic hybrids that would form with metal cations. Mn(II) was found to replace two of the six acid protons, while a third proton bonds to the nitrilo nitrogen, forming a zwitter ion. Two types of compounds were obtained. When the ratio of acid to Mn(II) was less than 10, a trihydrate, Mn[HN(CH(2)PO(3)H)(3)(H(2)O)(3)] (2) formed. Compound 2 is monoclinic P2(1)/c, with a = 9.283(2) A, b = 16.027(3) A, c = 9.7742(2) A, beta = 115.209(3) degrees, V = 1315.0(5) A(3), and Z = 4. The Mn atoms form zigzag chains bridged by two of the three phosphonate groups. The third phosphonate group is only involved in hydrogen bonding. The metal atoms are octahedrally coordinated with three of the sites occupied by water molecules. Adjacent chains are hydrogen-bonded to each other through POH and HN donors, and the additional participation of all the water hydrogens in H-bonding results in a corrugated sheet-like structure. Use of excess NTP at a ratio to metal of 10 to 1 yields an anhydrous compound Mn[HN(CH(2)PO(3)H)(3)] (1), P2(1)/n, a = 9.129(1) A, b = 8.408(1) A, c = 13.453(1) A, beta = 97.830(2) degrees, V = 1023.0(2) A(3), and Z = 4. Manganese is five coordinate forming a distorted square pyramid with oxygens from five different phosphonate groups. The sixth oxygen is 2.85 A from an adjacent Mn, preventing octahedral coordination. All the protonated atoms, three phosphonate oxygens and N, form moderately strong hydrogen bonds in a compact three-dimensional structure. The open-structured trihydrate forms a series of isostructural compounds with other divalent transition metal ions as well as with mixed-metal compositions. This is indicative that the hydrogen bonding controls the type of structure formed irrespective of the cation.

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PubMed2002

Metal carboxylate-phosphonate hybrid layered compounds: synthesis and single crystal structures of novel divalent metal complexes with N-(phosphonomethyl)iminodiacetic acid.

Two novel divalent metal complexes with N-(phosphonomethyl)iminodiacetic acid, H(2)O(3)PCH(2)N(CH(2)CO(2)H)(2) (H(4)PMIDA), [Co(2)(PMIDA)(H(2)O)(5)] x H(2)O, 1, and [Zn(2)(PMIDA)(CH(3)CO(2)H)] x 2H(2)O, 2, have been synthesized and structurally characterized. The structure of complex 1 features two different kinds of Co(II) layers, namely, a cobalt phosphonate layer along the <100> plane and a cobalt carboxylate layer along the <300> plane. The Co(II) atoms in the phosphonate layer are octahedrally coordinated by 4 aqua ligands and 2 oxygen atoms from two phosphonic acid groups. Two Co(II) octahedra are bridged by a pair of phosphonic groups into a dimeric unit, and such dimers are interconnected into a layer through hydrogen bonding between aqua ligands. The Co(II) atoms in the carboxylate layer are octahedrally coordinated by a chelating PMIDA ligand, one aqua ligand, and one phosphonic oxygen atom from the neighboring PMIDA ligand. These Co(II) octahedra are interlinked by bridging carboxylic groups into a one-dimensional chain along the c-axis; such chains are held together by hydrogen bonds formed between carboxylic oxygen atoms and lattice water molecules, in such a way as to form a layer along the <300> direction. Two such layers are interconnected into a double layer via hydrogen bonding. These double layers are further interconnected with the Co(II) phosphonate layers through phosphonate tetrahedra along the a direction, resulting in the formation of a complicated three-dimensional network. The crystal structure of 2 contains a metal phosphonate and metal carboxylate hybrid layer along the <202> plane. One of the two zinc atoms in the asymmetric unit is tetrahedrally coordinated by four oxygen atoms from two phosphonic acid groups and two carboxylic groups; the other zinc atom is 5-coordinated by three oxygen atoms and a nitrogen atom from a chelating PMIDA ligand and one oxygen atom from the acetic acid. The above two types of zinc metal ions are interconnected by bridging carboxylic and phosphonic groups, resulting in the formation of a layered structure.

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PubMed2002

Synthesis, characterization, and crystal structures of two divalent metal diphosphonates with a layered and a 3D network structure.

Reactions of N-methyliminobis(methylenephosphonic acid), CH(3)N(CH(2)PO(3)H(2))(2) (H(4)L), with divalent metal acetates under different conditions result in metal diphosphonates with different structures. Mn(H(3)L)(2).2H(2)O (complex 1) with a layer structure was prepared by a layering technique. It is triclinic, P1 macro with a = 9.224(3) A, b = 9.780(3) A, c = 10.554(3) A, alpha = 82.009(6) degrees, beta = 74.356(6) degrees, gamma = 89.853(6) degrees, Z = 2. The Mn(II) ion is octahedrally coordinated by six phosphonate oxygen atoms from four ligands, two of them in a bidentate and two in a unidentate fashion. Each MnO(6) octahedron is further linked to four neighboring MnO(6) octahedra through four bridging phosphonate groups, resulting in a two-dimensional metal phosphonate (002) layer. These layers are held together by strong hydrogen bonds between uncoordinated phosphonate oxygen atoms. The zinc complex Zn(3)(HL)(2) (complex 2) was synthesized by hydrothermal reactions (4 days, 438 K, autogenous pressure). It is monoclinic, P2(1)/n with a = 7.7788(9) A, b = 17.025(2) A, c = 13.041(2) A, beta = 94.597(2) degrees, Z = 4. The structure of complex 2 features a 3D network built from ZnO(4) tetrahedra linked together by bridging phosphonate groups. Each zinc cation is tetrahedrally coordinated by four phosphonate oxygen atoms from four ligands, each of which connects with six zinc atoms, resulting in voids of various sizes. Magnetic measurements for the manganese complex shows an antiferromagnetic interaction at low temperature. The effect of the extent of deprotonation of phosphonic acids on the type of complex formed is discussed.

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PubMed1999

Synthesis and X-ray Powder Structure of a New Pillared Layered Cadmium Phosphonate, Giving Evidence that the Intercalation of Alkylamines into Cd(O(3)PR).H(2)O Is Topotactic.

A new pillared layered phosphonate, cadmium 2-aminoethylphosphonate, Cd(O(3)PC(2)H(4)NH(2)) (1), has been synthesized, and its structure was solved ab initio from X-ray powder diffraction data and refined by Rietveld methods. Compound 1 is orthorhombic: space group Pna2(1), a = 15.4643(2) Å, b = 5.16512(7) Å, c = 6.27650(8) Å, and Z = 4. Its layer arrangement is similar to that in Cd(O(3)PR).H(2)O, except that the water molecule coordinated to cadmium in Cd(O(3)PR).H(2)O is replaced by the nitrogen atom from the amino ends of the ethyl chains borne by phosphorus of the upper and lower layers. The strong similarity of the IR, (31)P, and (113)Cd NMR data for Cd(O(3)PC(2)H(4)NH(2)) and Cd(O(3)PCH(3)).n-NH(2)C(4)H(9) clearly shows the topotactic character of the intercalation of n-alkylamines in the dehydrated form of Cd(O(3)PR).H(2)O to yield Cd(O(3)PR).n-NH(2)R'.

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