Rheological phase synthesis and characterization of a series of metal diphosphonate compounds

3D Ni and Co redox-active metal–organic frameworks based on ferrocenyl diphosphinate and 4,4′-bipyridine ligands as efficient electrocatalysts for the hydrogen evolution reaction

New 3D Ni and Co redox-active metal–organic frameworks based on ferrocenyl diphosphinate and 4,4′-bipyridine ligands have been explored as efficient electrocatalysts with superior long-term durability in a hydrogen evolution reaction.

Structural, spectral and magnetic studies of two Co(II)-N-heterocyclic diphosphonates based on multinuclear units

Two examples of Co(II)-N-heterocyclic coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L=CH3C(OH)(PO3H2)2), namely 0.5(H3NCH2CH2NH3)·[Co6(Cl2)(H3L)2(H2L)(HL)(2,2'-bipy)6] 1 and 2(NH4)·[Co3(HL)2(H2O)2(phen)2]·2(H2O) 2, have been solvothermally obtained by introducing the second ligands 2,2'-bipyridine/1,10-phenanthroline (2,2'-bipy/phen) and characterized by powder X-ray diffraction (PXRD), elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that compound 1 possesses a 0-D structure with hexa-nuclear cluster [Co6(O-P-O)8] built through single/double O-P-O bridges and compound 2 displays a 1-D ladder-like chain structure with magnetic topology building blocks [Co4(O-P-O)4]n. Then H-bonding and π-π stacking interactions further expand the two low-dimensional structures into three-dimensional supramolecular frameworks. Fluorescent measurements reveal that both the maximum emission peaks of 1-2 are centered at 423nm, mainly deriving from intraligand π*-π transition state of N-heterocyclic ligand 2,2'-bipy/phen, respectively. Magnetism data indicate that 1 exhibits antiferromagnetic behavior within hexa-nuclear Co(II) clusters, while 2 shows weak ferromagnetic interactions in 1-D topology Co(II)-chain, showing promising potential as magnetic materials.

Crystal structure of bis-[(1-ammonio-1-phosphono-eth-yl)phospho-nato]tetra-aqua-cadmium dihydrate: a powder X-ray diffraction study

In the compound [CdL₂(H₂O)₄]·2H₂O [L = (1-ammonio-1-phosphono­eth­yl)phospho­nate, C₂H₈NO₆P₂⁻], the Cd^II ion is situated on an inversion centre being coordinated by four aqua mol­ecules in the equatorial plane and two deprotonated phospho­nate O atoms from two L ligands in the axial positions in a distorted octa­hedral geometry. Each ligand L exists in a zwitterionic form, and with an intra­molecular O—H⋯O inter­action forming an S(6) ring motif and two intra­molecular N—H⋯O inter­actions each generating an S(5) ring motif. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds link complex mol­ecules into a three-dimensional network with voids of 38 ų filled with ordered lattice water mol­ecules, which are also involved in O—H⋯O hydrogen bonding.

In the title compound, [CdL₂(H₂O)₄]·2H₂O [L = (1-ammonio-1-phosphono­eth­yl)phospho­nate, C₂H₈NO₆P₂⁻], the Cd^II ion is situated on an inversion centre being coordinated by four aqua mol­ecules in the equatorial plane and two phosphonate O atoms from two deprotonated L ligands in the axial positions in a distorted octa­hedral geometry. The asymmetric unit contains one-half of the complex mol­ecule and one lattice water mol­ecule. The ligand L exists in a zwitterionic form, with a positive charge on the NH₃ group and a negative charge on the O atom of the non-coordinating phospho­nate group, and with an intra­molecular O—H⋯O inter­action forming an S(6) ring motif and two intra­molecular N—H⋯O inter­actions each generating an S(5) ring motif. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds link the complex mol­ecules into a three-dimensional network in which the voids of 38 ų are filled with ordered lattice water mol­ecules, which are also involved in O—H⋯O hydrogen bonding.

Two novel Cu(II) diphosphonates: structural, spectral and magnetic studies

By introducing the second organic N-heterocyclic ligands 2,2'-bipyridine (2,2'-bipy)/1,10-phenanthroline (phen), two mono-/bi-nuclear examples of Cu(II)-diphosphonate coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L=CH3C(OH)(PO3H2)2), [Cu(H4L)2(2,2'-bipy)]·H2O 1 and [Cu(H3L)(phen)]2·(HOCH2CH2OH)0.52, have been solvothermally obtained and characterized by powder X-ray diffraction, elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that both the two compounds possess zero-dimensional structures, built from mononuclear unit [CuO4N2]n for 1 and binuclear unit [-Cu-O-P-O-]2n with a double O-P-O bridge for 2 in syn-anti fashion. Then H-bond or/and π-π interactions further expand the two zero-dimensional structures into the three-dimensional supramolecular frameworks. Fluorescent measurements reveal that the maximum emission peaks of 1-2 centered at 433.5nm for 1 and 434.5nm for 2, respectively, are mainly caused by intraligand π(*)-π emission state of N-heterocyclic ligands (λex=235nm). The further magnetic study shows the two coordination polymers exhibit antiferromagnetic behavior for 1 between the mononuclear units, while ferromagnetic behavior for 2 derived from double O-P-O bridges in syn-anti mode between the metal centers.

Bis(1-ammonioethane-1,1-diyldiphosphonato-κ2O,O′)diaquacobalt(II) nonahydrate

In the title compound, [Co(C₂H₈NO₆P₂)₂(H₂O)₂]·9H₂O, the Co^II atom has a slightly distorted octa­hedral coordination environment consisting of four deprotonated phospho­nate O atoms of two independent 1-amino­ethyl­idendiphospho­nate anions and complemented by the O atoms of two water mol­ecules in cis positions. The anions exists in the zwitterionic form (protonated amino group and two deprotonated phospho­nate O atoms) and constitute two six-membered chelate rings. The crystal structure also contains nine partly disordered uncoordinated water mol­ecules, which create an extensive three-dimensional network of strong O—H⋯O and N—H⋯O hydrogen bonds.

Bis[1-hydroxy-ethyl-idenediphosphon-ato(1-)](1,10-phenanthroline)nickel(II) mono-hydrate

In the mononuclear title compound, [Ni(C₂H₆O₇P₂)₂(C₁₂H₈N₂)]·H₂O, the Ni^II atom (site symmetry 2) is bonded to two phosphate-based O,O′-bidentate chelate ligands and one N,N′-bidentate 1,10-phenanthroline ligand, resulting in a slightly distorted cis-NiN₂O₄ octa­hedral geometry. In the crystal structure, pairs of complexes are linked by double hydrogen bonds, forming a one-dimensional chain-like structure. Aromatic π–π stacking inter­actions [centroid–centroid separation = 3.768 (2) Å] and further hydrogen bonds generate a two-dimensional structure. The water O atom also lies on a crystallographic twofold axis.