One-pot solvothermal reactions of CoCl2·6H2O with semi-rigid ligand 3-(pyridin-4-yl)-1H-pyrazole-5-carboxylic acid under different reaction temperature and stoichiometry conditions gave rise to three new complexes: [Co(Hppza)2(H2O)2] (1) and [Co(Hppza)2]n (2) and [Co(Hppza)(H2O)Cl]n...