4,4′-(Ethane-1,2-diyl)dipyridinium bis­(2-hy­droxy­benzoate)

In the crystal structure of the title compound, C12H14N2 2+·2C7H5O3 −, the cations and anions are linked via N—H⋯O hydrogen bonds and weak inter­molecular C—H⋯O inter­actions also occur. π–π stacking is observed between the nearly parallel benzene and pyridine rings [dihedral angle = 6.03 (8)°], the centroid–centroid separation being 3.7546 (16) Å. The 4,4′-(ethane-1,2-diyl)dipyridinium cation is centrosymmetric and the mid-point of the ethyl­ene C—C bond is located on an inversion center. An intra­molecular O—H⋯O hydrogen bond occurs in the anion

Poly[[aqua­tris­(μ4-benzene-1,2-dicarboxyl­ato)dilanthanum(III)] hemihydrate]

The asymmetric unit of the title coordination polymer, {[La2(C8H4O4)3(H2O)]·0.5H2O}n, contains two independent LaIII atoms, one of which is surrounded by eight carboxyl­ate-O atoms from six benzene-1,2-dicarboxyl­ate (BDC) anions in a bicapped trigonal–prismatic geometry. The other LaIII atom is nine-coordinated in a tricapped trigonal–prismatic geometry, formed by eight carboxyl­ate-O atoms from six BDC anions and a coordinated water mol­ecule. The BDC anions bridge the LaIII atoms, forming a two-dimensional polymeric complex parallel to (001). The crystal structure contains weak O—H⋯O and non-classical C—H⋯O hydrogen bonds. A C—H⋯π inter­action is also present in the crystal structure. The uncoordinated water molecule shows half-occupation

4,4′-Ethyl­enedipyridinium bis­(3,4,5-trihy­droxy­benzoate) sesquihydrate

The asymmetric unit of the title compound, C12H14N2 2+·2C7H5O5 −·1.5H2O, contains two 4,4′-ethyl­enedipyridinium cations, four gallate anions and three water mol­ecules. In the 4,4′-ethyl­enedipyridinium cations, the dihedral angles between the pyridinium rings are 4.3 (3) and 18.6 (3)°. Extensive classical N—H⋯O and O—H⋯O hydrogen bonding and weak C—H⋯O hydrogen bonding and C—H⋯π inter­actions are present in the crystal structure. π–π stacking is also observed, the centroid–centroid separations between the benzene and pyridine rings being 3.611 (3), 3.448 (3) and 3.536 (3) Å

Poly[(μ4-pyridine-2,3-dicarboxyl­ato)lead(II)]

In the title coordination polymer, [Pb(C7H3NO4)]n, the PbII ion is eight-coordinated in a distorted square-anti­prismatic geometry formed by one pyridine N atom and seven carboxyl­ate O atoms from four pyridine-2,3-dicarboxyl­ate (pda) anions. In the pda anion, the dihedral angles between the pyridine ring and carboxyl­ate groups are 19.5 (6) and 73.3 (6)°. The carboxyl­ate groups of the pda anions bridge the Pb ions, forming a two-dimensional coordination polymer parallel to (100). Weak inter­molecular C—H⋯O hydrogen boning is present in the crystal structure

4-Amino­benzoic acid–4,4′-(propane-1,3-diyl)dipyridine (1/1)

In the crystal structure of the title compound, C13H14N2·C7H7NO2, the 4,4′-trimethyl­ene-dipyridine (TMDP) mol­ecule displays an approximately planar structure, the maximum atomic deviation excluding H atoms being 0.118 (2) Å and the dihedral angle between the pyridine rings 4.59 (10)°. The TMDP and 4-amino­benzoic acid (ABA) mol­ecules are linked by O—H⋯N and N—H⋯N hydrogen bonding, while ABA mol­ecules are linked by O—H⋯O hydrogen bonding. C—H⋯π interactions are also observed between the methyl­ene groups of TMDP mol­ecules and the benzene rings of ABA mol­ecules

catena-Poly[bis(μ3-3-aminobenzoato-κ4 N:O:O,O′)bis(μ2-3-aminobenzoato-κ3 O,O′:O)dilead(II)]

The PbII atom in the title compound, {[Pb2(C7H6NO2)4]}n, is chelated by two 3-aminobenzoato ligands in a distorted pentagonal-bipyramidal coordination geometry with five oxygen donors in the equatorial positions, one nitro­gen donor and one oxygen donor in the axial positions. Two mol­ecules are linked through a centre of inversion, forming a dinuclear entity. These entities are linked in a μ3-bridging mode through the amino N atom and two carboxyl­ate O atoms into a chain along the b axis. Classical inter­molecular N—H⋯O hydrogen bonding is observed in the structure. The supra­molecular structure is consolidated by π–π stacking inter­actions with centroid–centroid distances between benzene rings of 3.837 (8) Å

Poly[[tetra­aqua­bis­(μ3-pyridine-2,6-dicarboxyl­ato)(μ2-pyridine-2,6-dicarboxyl­ato)dilanthanum(III)] dihydrate]

There are two independent LaIII cations in the polymeric title compound, {[La2(C7H3NO4)3(H2O)4]·2H2O}n. One is nine-coordinated in an LaN2O7 tricapped trigonal–prismatic geometry formed by three pyridine-2,6-dicarboxyl­ate anions and two water mol­ecules, while the other is ten-coordinated in an LaNO9 bicapped square-anti­prismatic geometry formed by four pyridine-2,6-dicarboxyl­ate anions and two water mol­ecules. The two LaIII cations are separated by a non-bonding distance of 5.026 (3) Å. The pyridine-2,6-dicarboxyl­ate anions bridge the LaIII cations, forming a three-dimensional polymeric complex. The crystal structure contains extensive classical O—H⋯O hydrogen bonds and weak inter­molecular C—H⋯O hydrogen bonds. The crystal structure is further consolidated by π–π stacking between pyridine rings, the shortest centroid–centroid distance between parallel pyridine rings being 3.700 (5) Å

Poly[[hexa­aqua­(μ2-oxalato-κ4 O 1,O 2:O 1′,O 2′)bis(μ3-pyridine-2,4-dicarboxyl­ato-κ4 N,O 1:O 1′:O 4)dicerium(III)] monohydrate]

In the polymeric title compound, {[Ce2(C7H3NO4)2(C2O4)(H2O)6]·H2O}n, the Ce3+ cation is nine-coordinated in a distorted CeNO8 tricapped trigonal–prismatic geometry, formed by three pyridine-2,4-dicarboxyl­ate anions, one oxalate anion and three water mol­ecules. The mid-point of the oxalate anion is located on an inversion center. The oxalate and pyridine-2,4-dicarboxyl­ate anions bridge the Ce3+ cations, forming a two-dimensional polymeric complex parallel to (010). Inter­molecular classical O—H⋯O hydrogen bonding and weak C—H⋯O hydrogen bonding are present in the crystal structure and π–π stacking [centroid–centroid distance = 3.558 (2) Å] is observed between parallel pyridine rings of adjacent mol­ecules. The uncoordinated water mol­ecule shows an occupancy of 0.5

On the String Equation of the BKP Hierarchy

The Adler-Shiota-van Moerbeke formula is employed to derive the $W$-constraints for the $p$-reduced BKP hierarchy constrained by the string equation. We also provide the Grassmannian description of the string equation in terms of the spectral parameter.Comment: 17 page