In the title co-crystal, C(22)H(16)O(10)·C(22)H(18)O(8), the independent tetra-methyl 9,10-dihydro-9,10-dioxoanthracene-2,3,6,7-tetra-carboxyl-ate, (I), and tetra-methyl anthracene-2,3,6,7-tetra-carboxyl-ate, (II), components occupy separate crystallographic inversion centers. In (II), the dihedral angles between the mean aromatic plane and the two independent carboxyl-ate planes are 41.32 (10)...

Isolated soil humic acid (HA) and commercial Aldrich HA were derivatized by esterification with methanol-thionyl and acetylation with acetic anhidride, in order to obtain derivatives with selectively blocked carboxyl and phenol groups, respectively. Results obtained by FT-IR spectroscopy and potentiometry show that the methanol-thionyl procedure is a selective, specific and efficient route for ...

The title compound, [Ho(2)(C(9)H(9)O(3))(6)(C(12)H(8)N(2))(2)], lies about a centre of symmetry and is comprised of six 2-phen-oxy-propionate (POPA) anions and two 1,10-phenanthroline (phen) ligands. The two Ho(III) ions are linked by four POPA groups utilizing both bi- and tridentate bridging modes to form an inversion-symmetric dimer. Each Ho(III) ion is nine-coordinate, with a chelating 1,10...

In the title compound, C(16)H(28)N(4)O(8)·2H(2)O, the 12-membered macrocycle has twofold crystallographic symmetry and the asymmetric unit comprises one half-mol-ecule. The four carbox-yl/carboxyl-ate groups reside on the same side of the macrocycle. The mol-ecule is a double zwitterion with two of the carb-oxy-lic acid H atoms transferred to the two N atoms on the opposite sides of the macrocy...

The title compound [Cu(2)(C(6)H(3)BrNO(2))(4)](n), forms sheets in the bc plane. The structure features the dinuclear paddle-wheel cage motif common to copper(II) carboxyl-ates. The polymeric structure is achieved through bridging between binuclear units by the pyridyl donors of two of the four carboxyl-ates of the cage. Each cage engages in axial bonding at each copper atom to a pyridyl nitro-...