Análise estrutural de um compledo de níquel e de vários triterpenos por difração de raios-x / Structural analysis of one Ni complex and five triterpenes by x-ray diffraction.

AUTOR(ES)
DATA DE PUBLICAÇÃO

1989

RESUMO

This work consist of a theoretical introduction of the basic principles of x-ray diffraction by crystals, a brief descruption of the automatic diffractometer CAD-4 Enraf-Nonius and the Patterson and direct methods used in structure determination. The crystals structures of one Ni(II) complex and Five triterpenes were solved. The five triterpenes are natural products extracted from the bark of Austroplenckia populnea (Celastraceae). Single crystals of the products were analyzed by X-ray diffraction, using the CAD-4 automatic diffractometer MοKα (λ= 0,71073Å) monochromatizated by a graphite crystal. The relevant crystallographic data are summarized in the table below:   triterpenos T1 T2 T3 T4 T5 Fórmula Química C31H48O4 C30H48O3 C31H48O3 C31H50O3 C30H48O4 Mr 484,73 456,71 468,73 470,74 472,71 Grupo Espacial P21 P1 C2 P212121 P21 a(Å) 6,697(2) 7,271(2) 12,109(2) 6,815(2) 14,695(2) b(Å) 14,714(7) 12,389(8) 7,346(2) 16,127(2) 13,699(2) c(Å) 13,866(3) 15,632(2) 30,570(6) 24,695(4) 6,622(3) α(°) 90 74,95(2) 90 90 90 β(°) 103,53(2) 87,55(2) 99,83(2) 90 104,45(2) γ(°) 90 86,76(4) 90 90 90 Z 2 2 4 4 2 V(Å3) 1328(1) 1357(1) 2679(2) 2714(2) 1288(1) dc(g⋅cm-3) 1,211 1,118 1,162 1,152 1,219 μ(cm-1) 0,726 0,651 0,675 0,668 0,733 F(000) 532 504 1032 1040 520 R 0,0485 0,0996 0,0574 0,0545 0,0420 Nº refl.: I>3σ(I) 1395 1972 751 1438 838 The Ni complex, [NiII(DPEH)2](NO3)2 2H2O, was synthesized from a 2M alcoholic solution of the ligand DPEH (Diacethylmonoxima - β - Pyridil-(2)-Ethylimina) for each mol of [Ni(OH2)6](NO3)2. A single crystal of this compound was analyzed by X-ray diffraction, using the CAD-4 automatic diffractometer MοKα (λ = 0,71073Å) monochromatizated by a graphite crystal. Principal crystallographic data are: monoclinic Cc, Mr = 629,27, a = 8,502(2), b = 18.702(2), c = 18.653(4)Å, β = 103,22(2)°, V = 2887(2)޵, Z = 4, dc = 1,448gcm-3, μ = 7,36cm-1, F(000) = 1312, R =0,0594 and 1656 reflections with I > 2ο(I). The Ni atom is coordinated to six N atoms in a distorted octahedrical configuration.

ASSUNTO(S)

ni complex difração de raios-x complexo ni triterpeno triterpene x-ray diffraction structure estrutura

ACESSO AO ARTIGO

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