| In the last decades, considerable efforts have been made to design and synthesize the Schiffbase complexes for they have strong coordination ability, good biological activities and otherexcellent properties, make them to be potential drugs and functional materials, the Schiff basecomplexes have attacted considerable interest and become one of the subjects of intensiveresearch. Seven crystal structures have been obtained by treatment pyridinecarbaldehydesemicarbazones with the transition metal salts, [(Cu(CHCN)2(PPh3)2)]ClO4, Co(CLO4)2.6H2O,Ni(ClO4)2.6H2O, CoAc2.4H2O, NiAc2.4H2O, respectiverly. The complexes have beencharacterized by a variety of spectroscopic techniques and the crystal and molecular structures aredetermined by single crystal X-ray diffraction techniques.The reaction of pyridinecarbaldehyde N-oxide semicarbazide and NaAc in ethanol in themolar ratio of 1:1:1 gave the ligand. The reaction of Schiff base and Co(ClO4)2.6H2O In 50%ethanol in the molar ratio of 3:1, compound [Co(PNOS )(ClO4)2·(PNOS)·H2O was furthersynthesized and red single crystal was obtained, compound (1) crystal belongs to triclinic system,space group p –1, with Unit cell parameters: a=9.180(2) A, b=12.908(3) A, c=14.265(4)A ,Dc=1.678Mg/m3 α=100.340(5)°,β=102.817(5)°,γ=92.411(5)°,V=1615.5(7) A3, Z=2,Mr=816.37 , μ=0.786mm-1, F(000)=834, final R=0.0728 and ωR=0.1354, the crystal is ioniccomplex, the centeral metal Co(II) of complex 1 adopts six-coordinated distorted octahedralgeometry, In the complex(1), PNOS is coordinated to cobalt(II) via the oxygen(N-O),nitrogen(C=N) and oxygen(C=O) atoms. In addition, there are a large number of strong hydrogenbondings(N-H…O,O-H…O) and weak hydrogen bondings(C-H…O) in involving the cations,perchlorate counter-ions,PNOS and water molecules, which result in formation 3-D networkstructure.The reactions of pyridine-2-carbaldehyde semicarbazone with transition metal (Ni(II),Co(II))salts afford two pyridine-2-carbaldehyde semicarbazone transition metal compounds. CompoundNi(H-pysc)2, C14H14N8NiO2, Mr=385.04, belongs to Tetragonal system, space group p 43, withUnit cell parameters: a=8.2766(12) A, b=8.2766(12) A, c=23.648(4) A ,Dc=1.579Mg/m3, α=90°,β=90°,γ=90°,V=1619.9(4) A3, Z=4, μ=1.225mm-1, F(000)=792, final R=0.0261 and ωR=0.0553, In the compound (2), the coordination geometry is a distorted octahedron and Ni(II)center chelates N atom of pyridine, the nitrogen (C=N) and oxygen (C-O) atoms. A large numberof hydrogen bonding(N-H…O,C-H…O) interactions in the pack of compound 2 forms two-Dnetwork structure. Compound [Co(H-pysc)2](ClO4)2(H2O), C14H18Cl2CoN8O14, Mr=604.19,belongs to triclinic system, space group p –1, with Unit cell parameters: a=9.984(3) A, b=11.082(4)A, c=12.196(4) A , Dc=1.769Mg/m3,α=112.954(4)°,β=110.050(4)°,γ=94.017(3)°,V=1134.4(7)A3, Z=2, μ=1.067mm-1, F(000)=614, final R=0.0501 and ωR=0.1028, H-pysc is coordinated tocobalt(II) by the N atom of pyridine, the nitrogen(C=N) and oxygen(C=O) atoms, the coordinationgeometry is a distorted octahedron. The three-dimensional supramolecular architecture is formedby a number of hydrogen bonds(O-H…O and N-H…O) involving the cations,perchloratecounter-ions and water molecules.A dinuclear complex [CuL2]2.(ClO4)2 (4) and three mononuclear complexes (5) ,(6) ,(7)have been synthesized respectively,through the reaction of pyridine-3(or4)-carbaldehydesemicarbazone by hydro(solvo)thermal treatment at 70℃. Compound 4 belongs to triclinic system,space group p –1, with Unit cell parameters: a=7.5444(6) A, b=8.7190(7)(4) A, c=16.2409(13)A ,Dc=1.687Mg/m3, α =76.601(2)) ° , β =84.352(2) ° , γ =68.560(1) ° ,V=967.2(1) A3, Z=1,μ=1.687mm-1, F(000)=500, final R=0.0720 and ωR=0.1346; Compound (5) belongs to triclinicsystem, space group p –1, with Unit cell parameters: a=7.8694(13) A, b=8.8660(13) A,c=10.2643(11) A ,Dc=1.576Mg/m3, α =65.788(11) ° , β =69.511(12) ° , γ =81.816(14)° ,V=611.83(15) A3, Z=1, μ...
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