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.

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.

N-heterocyclic amine-directed structures and properties of two Cu(II) diphosphonates.

By introducing the second organic N-heterocyclic ligands 4'-(4-pyridyl)-4,2':6',4''-terpyridine (pyterpy) and 4,4'-bipyridyl (4,4'-bipy), two examples of Cu(II)-diphosphonates, [Cu(3)(HL)(2)(Hpyterpy)(2)]·2H(2)O 1 and [Cu(4)(HL)(2)(4,4'-bipy)(H(2)O)(5)] 2 based on 1-hydroxyethylidenediphosphonic acid (H(5)L = CH(3)C(OH)(PO(3)H(2))(2)), have been hydrothermally obtained and characterized by powder X-ray diffraction, elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions reveal that compound 1 has a one-dimensional fishbone-like chain constructed by anions [Cu(3)(HL)(2)(2-)](n) while simultaneously organic cations [Hpyterpy(+)](n) suspending both sides, and compound 2 exhibits two-dimensional inorganic-organic alternate arrangement layer built from 1-D ladder-like inorganic chain with tetranuclear cluster [Cu(4)O(10)] via 4,4'-bipy linkage. The results of electrochemical measurements indicate half-wave potential of 1 (E(1/2)(1) = 1.01 V) is less than that of 2 (E(1/2)(2) = 1.20 V), indicating a good D-A system in ICT for 1. Moreover fluorescent measurements reveal that emission intensity of 1 centered at 422 nm is larger than that of 2 emitted at 420 nm, caused by intraligand π*-π emission state of organic N-heterocyclic amine (λ(ex) = 233 nm). Magnetism data indicate that compound 1 exhibits ferrimagnetic interactions between metal centers, while compound 2 has antiferromagnetic property.

catena-[[(nitrato-κO)silver(I)]-µ-1,10-phenanthroline-5,6-dione-κO,O':N,N'].

In the title one-dimensional coordination polymer, [Ag(NO(3))(C(12)H(6)N(2)O(2))](n), the Ag(I) atom is penta-coordinated by two N atoms from a 1,10-phenanthroline-5,6-dione (phen-dione) ligand, one O atom from the nitrate anion and two O atoms from another phen-dione ligand. The coordination environment around silver is slightly distorted square-pyramidal. Inter-estingly, the Ag-O distances to the phen-dione ligand are different [Ag-O = 2.612 (6) and 2.470 (5) Å]. The one-dimensional chains run parallel to [101] and are further inter-connected by weak hydrogen bonds (C-H⋯O) and π-π stacking inter-actions [centroid-centroid distances 3.950 (4) and 3.792 (4) Å], forming a three-dimensional supra-molecular network.

[Resolution of the epinephrine enantiomers derivatized with fluorescent chiral reagent by reversed-phase high performance liquid chromatography].

A new method was developed to separate epinephrine enantiomers derivatized with fluorescent chiral reagent, R-(-)/S-(+)-4-(N, N-dimethylaminosulfonyl)-7-(3-iso-thiocyanatopyrrolidino)-2, 1, 3-benzoxadiazole (DBD-PyNCS), by reversed-phase high performance liquid chromatography, on a Diamonsil C18 column(150 mm x 4.6 mm i.d., 5 microns), with a mobile phase of water-acetonitrile(72:28, volume ratio) and a fluorescent detector at the excitation wavelength of 460 nm and the emission wavelength of 550 nm. The column was eluted at 40 degrees C, with a flow rate of 1 mL/min. At first, let the fluorescent chiral reagent(36 mmol/L, 10 microL) react with epinephrine enantiomers(1 mmol/L, 10 microL), and then 10 microL 20% pyridine acetonitrile solution was added. The resulting mixture was stirred for 1 min and kept at 65 degrees C for 35 min and then a 10 microL aqueous of the diastereomeric derivatives was injected directly into the chromatograph. The diastereomeric compounds were efficiently separated. The Rs value was 2.6 with alpha of 1.07. The k's of L-epinephrine and D-epinephrine were 17.11 and 18.13 respectively. The retention times of L-epinephrine and D-epinephrine were 30.24 min and 31.94 min respectively. The linear range was 0.07 g/L -0.50 g/L (r = 0.9995). The RSD was 4.3%(n = 7). The detection limit was 12 g/L(S/N = 3).