CRYSTAL AND MOLECULAR STRUCTURE OF THE ADDUCT OF Ni(TAAB)(BF_4)_2WITH PYRIDINE

The crystal structure of [Ni(TAAB)(py)_2](BF_4)_2,where TAAB is the tetradentate macrocyclic ligand tetrabenzo[b,f,j,n] [1,5,9,13] tetraazacyclohexadecine,has been determined from X-ray diffraction analysis.The crys. tai beiongs to monoclinic,space group P2_1/n with cell parameters a=16.465(6),b =12.486(5),e=20.219(1),β=113.79°, V=3803.9~3,Z=4,De=1.402 g/cm^3,F(000)=1640,The molecule has approximately S_4 symmetry.TAAB macrocyelic ligand presents a decidedly saddle-shaped appearance.Planes pyridine molecules are perpendicular to each other and the nickle(II)ion has coordination geometry.The final R and Rw are 0.068 and 0.070,respectively.

Crystal and Molecular Structure of Copper (Ⅱ) Dimeric Complex of S-Methyl-β-N-(Pyridine N-Oxide-2-ylmethylidene) Dithiocarbazate with Acetonitrile

The crystal and molecular structure of copper(Ⅱ) dimeric complex of S-methyl-B-N-(pyridine N-oxide-2-ylmethylidene) dithiocarbazate with acetonitrile, [CuL (CH3CN)]2 (ClO4)2, was determined by X-ray diffraction. The complex crystalizes in monoclinic system with space group P21/n, a= 7. 685(2), 6=20.160(6), c= 10. 847(5) A ,B = 107.89(3), Z=2,Dc=1.788 g/cm3, F(000) = 835. 8, u= 18. 17 cm-1(Moka,R= 0. 057.Each Cu(Ⅱ) ion in the complex is surrounded by a distorted square pyramidal. The basal plane is comprised of S, N and O atoms of one ligand together with a N atom of the solvent--acetonitrile, while the axial position is occupied by the S atom of the other ligand. The bond length of Cu-S(bridging) is 3. 038A . and Cu-Cu distance is 3. 700A.

Crystal and molecular structure of 2,3-benzo-1,4,7,13-tetraoxa-10-selenacyclopentadeca-2-ene

The crystal structure of 2,3-benzo-1,4,7,13-tetraoxa-10-selenacyclopentadeca-2-ene was de- termined,C_(14)H_(20)O_4Se,M_r:331.27,orthorhombic,Pbca,a=18.445(3),b=16.334(4),c9.232(2) ,V=2781.3 ~3,Z=8,Dx=1.582 Mg m^(-3),λ(Mo K_α)=0.71073 ,μ=26.77 cm^(-1),F(000)=1360, T=297 K,R=0.0329,R_w=0.0438 for 2192 reflections with I>3 σ(I).The crystal structure is closely related to that of benzo-15-crown-5(at 123 K),whereas the molecular geometry of the two coronands is different according to their torsion angles calculated and the shapes exhibited.

Crystal and molecular structure of(μ-p-CH_3C_6H_4C_2S) (μ-n-C_3H_7S)Fe_2(CO)_6CO_2(CO)_6

The crystal and molecular structure of the complex containing cobalt-carbon and iron- sulfur cluster cores,(μ-ρ-CH_3C_6H_4C_2S)(μ-n-C_3H_7S)Fe_2(CO)_6Co_2(CO)_6,has been determined by X-ray diffraction method.The crystals are triclinic,space group P,with a=9.139(2),b=9.610(1), c=17.183(2),α=84.36(1),β=89.45(1),γ=88.15(1)°,V=1501.0~3;Z=2,D_c=1.74 g/cm^3. R=0.072,Rw=0.081.The results of the structure determination show a cobalt-carbon cluster core formed through the reaction of(μ-ρ-CH_3C_6H_4C_2S)(μ-n-C_3H_7S)Fe_2(CO)_6 with Co_2(CO)_8.In the cobalt-carbon cluster core,the bond length of the original C≡C lengthened to 1.324 which is close to the typical value of carbon-carbon double bond.The groups connecting the carbons of the cluster core are in cis position and lie on the opposite side of cobalt atoms.In this complex,the conformation of-SC_3H_7 is e-type,while that of-SC_2C_6H_4CH_3 is a-type.

Crystal and molecular structure of guanidinium hexatungsto-bis(p-aminophenylarsonate)tetrah ydrate,[C(NH_2)_3]_4[(p-NH_3C_6H_4As)_2W_6O_(25)].4 H_2O

The crystal structure of a new type arylarsonic polytungstate[C(NH_)_]_4[p-NH_3C_6H_4As)_2- W_6O_(25)]·4H_O was determined by single-crystal X-ray diffraction analysis.It belongs to triclinic,space group P,with cell dimensions a=12.863(3),b=18.912(3),c=21.383(4)α=91.14(2)°,β= 93.65(3)°,γ=92.25(3)°,V=5185.9~3,Z=4,D_c=2.753g/cm^3.The intensity data were collected on an Enraf-Nonius CAD4 diffractometer with Mo Kα radiation.The positions of all tungsten and arsenic atoms were determined by direct method.The other non-hydrogen atoms were revealed by difference Fourier synthesis.The structure was refined by fullmatrix least-squares procedure to a final R value of 0.070.The crystal structure contains two similar but nonidentical molecules.Two similar anions consist of a ring of six WO_6 octahedra,which are connected with one face-sharing,two corner-sharings and three edge-sharings,and two p-aminophenylarsonic tetrahedra capped above and below the ring. In each WO_6 ring,four tungsten atoms,which are joined with edge-sharing oxygen atoms,are almost coplanar,while the two others,which are joined with face-sharing oxygen atoms,protrude out of the ring towards the same side.The two arsenic atoms in each anion are not equivalent in their bonding manner.In each anion,all non-hydrogen atoms of each organic group are in the same plane.Each molecule contains one anion,four C(NH_2)_3^+ cations and four water molecules.There are many hydrogen bonds between cations and anions throughout the whole crystal.The amino groups can accept protons,so that the charge of the resulting anion decreases and[(RAs)_2W_6O_(25)]^(4-)type complexes are formed.

Crystal and molecular structure of main adduct of benzaldoxime dehydrodimer and styrene

Three 1:1 adducts have been obtained by heating benzaldoxime dehydrodimer with styrene. The main product possesses the structure of bis-nitrone type. A radical addition mechanism is pro- posed.