Structure and magnetic properties of a novel copper diphosphonate with pillared layered structure:

The O–P–O bridged Mn2(salen)2chains showing coexistence of single chain magnet and metamagnet behaviour

Three chain compounds in which the Mn₂(salen)₂dimers are bridged by O–P–O units are reported, two of which display coexistence of SCM behavior and metamagnetism at low temperature.

catena-Poly[[[tetraaquamagnesium]-trans-μ-[(piperazine-1,4-diium-1,4-diyl)bis(methylene)]diphosphonato] hemihydrate]

The structure of the title polymer, }[Mg(C₆H₁₄N₂O₆P₂)(H₂O)₄]·0.5H₂O}_n, is based on centrosymmetric MgO₆ octahedra, which are linked by [(piperazine-1,4-diium-1,4-di­yl)bis­(methyl­ene)]di­phospho­nate ligands, forming chains parallel to [1-1-1]. These chains are connected via hydrogen bonds primarily formed between the phospho­nate groups and water mol­ecules. The latter constitute four of the corners of the MgO₆ polyhedra and bind to the O atoms of the phospho­nate groups of neighbouring chains. The lattice water molecule is disordered around an inversion centre, exhibiting an occupancy of 0.25.

Structure and Characterization of a Novel 3D Lead Phosphonate Metal - Organic Framework with Cationic Layer Based on Weak Pb - O(N) Contact

A novel lead-phosphonate, [Pb2(HL)]·(NO3)·2(H2O) 1 (H4L = H2O3PCH2N(C4H8)NCH2PO3H2 N,N′-piperazinebis(methylenephosphonic acid), so HL = O3PCH2NH(C4H8)NCH2PO3), has been hydrothermally synthesized and characterized by elemental analysis, IR, TG-DTA, and X-ray single-crystal diffraction. Compound 1 possesses a 2D cationic layer structure built from inorganic chains with three types of eight-membered rings arranged in an ABAC manner. In 1, both crystallographic distinct Pb(II) ions adopt three-coordination geometry, and a counter anion NO3 – and two lattice water molecules occupy the voids between 2D layers. After the removal of solvent, the size of tunnel formed by 2D layers is 137.9 Å3 per unit cell, comprising 17.0% of the crystal volume based on the crystal structure. When the bond length of Pb–O(N) extended to 3.10 Å, a 3D metal–organic framework was constructed via long Pb–O(N) contacts, simultaneously accompanied by the hemi- to holo-directed transition in coordination geometry of Pb(II). Except for the long Pb–O contacts, a 3D supramolecular network is also formed by hydrogen bonds (N–H···O, O–H···O, and C–H···O), van der Waals forces as well as electrostatic interactions. The result of fluorescence measurements indicates that 1 shows a fluorescent emission band at 465 nm (λexcitation = 215 nm).

Three-Dimensional Lanthanide(III)–Copper(II) Compounds Based on an Unsymmetrical 2-Pyridylphosphonate Ligand: An Experimental and Theoretical Study

Based on an unsymmetrical 2-pyridylphosphonate ligand, two types of Ln(III)-Cu(II) compounds with three-dimensional structures were obtained under hydrothermal conditions, namely, Ln(2)Cu(3)(C(5)H(4)NPO(3))(6).4H(2)O (1.Ln; Ln=La, Ce, Pr, Nd) and Ln(2)Cu(3)(C(5)H(4)NPO(3))(6) (2.Ln; Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho). Compounds 1.Ln are isostructural and crystallize in chiral cubic space group I2(1)3. In these structures, each Ln ion is nine-coordinate and has a tricapped triprismatic geometry, while each Cu center is six-coordinate with an octahedral environment. The {LnO(9)} polyhedra and {CuN(2)O(4)} octahedra are connected by edge sharing to form an inorganic open framework structure with a 3-connected 10-gon (10,3) topology in which the Ln and Cu atoms are alternately linked by the phosphonate oxygen atoms. Compounds 2.Ln are isostructural and crystallize in trigonal space group R3. In these structures, the {LnO(6)} octahedra are triply bridged by the {CPO(3)} tetrahedra by corner sharing to form an infinite chain along the c axis. Each chain is connected to its six equivalents through corner sharing of {CPO(3)} tetrahedra and {CuN(2)O(2)} planes to form a three-dimensional framework structure in which the Ln and Cu atoms are linked purely by O-P-O units. The formation of these two types of structures is rationalized by quantum chemical calculations, which showed that both the lanthanide contraction and the electron configuration of Cu(II) play important roles. When Cu(II) was replaced by Zn(II), only the first type of compounds resulted. The magnetic properties of complexes 1.Ln and 2.Ln were investigated. The nature of Ln(III)-Cu(II) (Ln=Ce, Pr, Nd) interactions is illustrated by comparison with their Ln(III)-Zn(II) analogues.

Two New Hybrid Organic/Inorganic Copper(II)−Oxovanadate(V) Diphosphonates: [Cu2(phen)2(O3PCH2PO3)(V2O5)(H2O)]·H2O and [Cu2(phen)2(O3P(CH2)3PO3)(V2O5)]·C3H8. Synthesis, Structure, and Magnetic Properties

Two new hybrid organic/inorganic copper oxovanadium diphosphonates [Cu2(phen)2(O3PCH2PO3)(V2O5)(H2O)] x H2O (1) and [(Cu2(phen)2(O3P(CH2)3PO3)(V2O5)] x C3H8 (2) have been obtained by hydrothermal synthesis. The compounds are monoclinic, and they crystallize in the space group P2(1)/n with cell parameters of a = 11.788(2) A, b = 17.887(3) A, c = 14.158(2) A, and beta = 93.99(0) degrees and in the space group C2/c with cell parameters of a = 11.025(1) A, b = 18.664(2) A, c = 15.054(2) A, and beta = 90.06(0) degrees, respectively. Both compounds present two-dimensional frameworks built up from infinite chains of corner-sharing vanadium tetrahedra and diphosphonate groups connected by copper tetramers for (1) and copper dimers for (2). The remarkable feature of (2) is the encapsulation of propane molecules, stabilized by strong hydrogen bonding between the layers. The magnetic properties of the compounds have been investigated showing antiferromagnetic coupling with Tmax = 64 K for (1) and Curie-like paramagnetic behavior for (2).

Dinuclear and layered copper 2-pyridylphosphonates with weak ferromagnetism observed in layer compound Cu(C5H4NPO3)

This paper reports the syntheses and structures of three new copper phosphonates based on 2-pyridylphosphonate, namely, Cu(C(5)H(4)NPO(3)H)2 (1), Cu3(OH)2(C(5)H(4)NPO(3))2.2H2O (2) and Cu(C(5)H(4)NPO(3)) (3). Compound 1 has a discrete dimeric structure in which the {CuO(4)N} square pyramids are linked by the {CPO(3)} tetrahedra through corner-sharing. The dimers are further connected into a chain through hydrogen bonds. In compound 2, edge-sharing {Cu(1)O(4)N} square pyramids and {Cu(2)O(4)} planes are found to form an infinite chain with composition {Cu(3)(mu-OH)(2)(mu-O)(4)}. Neighboring chains are linked by the phosphonate groups of the 2-pyridylphosphonate ligands, resulting in inorganic layers containing 4-, 8- and 12-membered rings. The pyridyl groups and the lattice water molecules occupy the inter-layer space. In compound 3, the {Cu(1)O(4)} and {Cu(2)O(2)N(2)} planes are each corner-shared with the {CPO(3)} tetrahedra, forming an inorganic layer containing 8- and 16-membered rings. The pyridyl groups reside between the layers. Crystal data for 1: space group P(-)1, a = 8.4045(19), b = 8.751(2), c = 10.632(2) A, alpha = 66.673(4), beta = 72.566(4), gamma = 70.690(4) degrees , V = 664.7(2) A(3), Z = 2. Crystal data for 2: space group P2(1)/c, a = 7.9544(17), b = 21.579(4), c = 5.0243(10) A, beta = 105.332(3) degrees , V = 831.7(3) A(3), Z = 2. Crystal data for 3: space group P2(1)/c, a = 4.7793(11), b = 15.319(3), c = 8.6022(19) A, beta = 97.156(4) degrees , V = 624.9(2) A(3), Z = 4. Magnetic measurements reveal that dominant antiferromagnetic interactions are propagated between the copper centers in compounds 1-3. For 3, spin canting is observed with a ferromagnetic transition occurring at 9 K.

Three-, Two-, and One-Dimensional Metal Phosphonates Based on [Hydroxy(4-pyridyl)methyl]phosphonate: M{(4-C5H4N)CH(OH)PO3}(H2O) (M = Ni, Cd) and Gd{(4-C5H4N)CH(OH)P(OH)O2}3·6H2O

Based on the [hydroxy(4-pyridyl)methyl]phosphonate ligand, three compounds with formula Ni{(4-C(5)H(4)N)CH(OH)PO(3)}(H(2)O) (1), Cd{(4-C(5)H(4)N)CH(OH)PO(3)}(H(2)O) (2), and Gd{(4-C(5)H(4)N)CH(OH)P(OH)O(2)}(3).6H(2)O (3) have been synthesized under hydrothermal conditions. The crystal data for 1 are as follows: orthorhombic, space group Pbca, a = 8.7980(13) A, b = 10.1982(15) A, and c = 17.945(3) A. For 2 the crystal data are as follows: monoclinic, space group C2/c, a = 23.344(6) Angstroms, b = 5.2745(14) Angstroms, c = 16.571(4) Angstroms, and beta = 121.576(4) degrees. The crystal data for 3 are as follows: rhombohedral, space group R, a = 22.2714(16) Angstroms, b = 22.2714(16) Angstroms, and c = 9.8838(11) Angstroms. Compound 1 adopts a three-dimensional pillared layered structure in which the inorganic layers made up of corner-sharing {NiO(5)N} octahedra and {CPO(3)} tetrahedra are connected by pyridyl groups. A two-dimensional layer structure is found in compound 2, which contains alternating inorganic double chains and pyridyl rings. Compound 3 has a one-dimensional chain structure where the Gd atoms are triply bridged by O-P-O linkages. The pyridyl nitrogen atom in 3 remains uncoordinated and is involved in the interchain hydrogen bonds. Magnetic susceptibility studies of 1 and 3 reveal that weak ferromagnetic interactions are mediated between Ni(II) centers in compound 1. For compound 3, the behavior is principally paramagnetic.

The pH-controlled hydrothermal synthesis and crystal structures of two zinc N,N′-piperazinebis(methylenephosphonate) frameworks

An exploration of the reactions of N,N'-piperazinebis(methylenephosphonic acid), H4L, with zinc salts has led to the isolation of two new framework zinc phosphonates. ZnLH2.H2O (I) is isostructural with previously reported manganese(II) and cobalt(II) analogues, and consists of infinite 'zinc phosphate' chains bridged into three dimensions via the organic moieties. The resulting framework encloses large channels in which the loosely bound H2O resides. The H2O is lost reversibly at around 160 degree C, without framework collapse. Zn2L (II) has a novel framework structure, prepared at an initial pH > 7, which consists of two-dimensional 'zinc phosphate' sheets, comprising both four- and eight-membered -Zn-O-P- rings, which are also linked into three dimensions via the organic groups. In both cases, the zinc centre is tetrahedral; in I coordination is by oxygen atoms from four different phosphonate groups, whereas in II the additional deprotonation of the ligand allows coordination via three oxygen atoms plus the amine nitrogen atom.