XANES Study on the Generation and Distribution of Holes via Ca Substitution and O Doping in Cu(Ba0.8Sr0.2)2(Yb1xCax)Cu2O6+z

The two structurally related coordination polymers [Cu(ndc)(pyridine)], CPO-2-Cu, and [Zn(ndc)(3,4-lutidine)], CPO-2-Zn, were obtained by hydrothermal reactions between 2,6-naphthalenedicarboxylic acid (ndc), pyridine and copper(II) nitrate (CPO-2-Cu) and ndc, 3,4-lutidine and zinc(II) nitrate (CPO-2-Zn), respectively. The compounds are based on the binuclear paddle–wheel building unit. In both compounds these building units are connected into 2D sheets by naphthalene rings. In the third dimension there are weaker interactions involving the axial ligands pyridine and 3,4-lutidine. The sheets are stacked so that large 1D channels are formed into which the axial ligands protrude. The crystal structure of CPO-2-Cu was solved from synchrotron powder X-ray data, while the crystal structure of CPO-2-Zn was solved from conventional single-crystal X-ray data. Crystal data for CPO-2-Cu: Monoclinic space group C2/m (No. 12), a=10.2252(2), b=19.0915(4), c=8.0521(2) ?, beta=98.824(1)°, V=1553.30(7) ?3 and Z=4. Crystal data for CPO-2-Zn: Triclinic space group P-1 (No. 2), a=7.540(1), b= 10.711(1), c=11.196(2) ?, alpha=66.490(5)°, beta=87.265(6)°, chi=88.470(6)°, V=828.2(2) ?3 and Z=2. The thermal properties of both compounds were investigated as well as the magnetic properties of CPO-2-Cu.