Síntese e caracterização de ligantes oximas e tiossemicarbazonas e seus complexos
Resumo
Este trabalho apresenta a síntese e caracterização de cinco ligantes e quatro
complexos derivados de oximas e tiossemicarbazonas. Entre essas, discutem-se as
estruturas cristalinas/moleculares determinadas por difração de raios-X em monocristais: do
ligante 4-feniltiossemicarbazida-isatina (Ligante 5), do complexo piridina-salicilaldeído-4-
feniltiossemicarbazona de niquel (II) (Complexo 1), e do bis-4-feniltiossemicarbazona-
isatina de chumbo(II) (Complexo 2).
A estrutura do Ligante 5 cristaliza no sistema monoclínico, grupo espacial P21/c, com
parâmetros de cela a = 6,3227(2) A, b = 15,7973(7) A, c = 14,4572(6) A, ß = 93,9330(10)°, V
= 1440,61(10) A3 , Z = 4. O refinamento da estrutura convergiu aos índices de discordância
finais R1 = 0,0520, wR2 = 0,1471. Observa-se ainda a ocorrência de interações
intermoleculares do tipo ligações de hidrogênio clássicas [N18-H3 --- O1' 2,907(2)A], com a
formação de estruturas dímeras inter-relacionadas por simetria dentro da cela cristalina.
Para a estrutura cristalina do Complexo 1, observa-se NC=4, e geometria de
coordenação quadrada plana, onde o ligante saliciladeído-4-feniltiossemicarbazida
comporta-se como quelante tridentado, e completando a esfera de coordenação do centro
metalico temos uma molecula de piridina. A estrutura cristaliza no sistema monoclínico,
grupo espacial P21/m, parâmetros de cela a = 12,8211(2) A, b = 5,73370(10) A, c =
23,9950(4) Å, ß = 101,0910(10)°, V = 1730,98(5) A3, índices de discordância finais R1=
0,0320, wR2 = 0,0888, Z=3.
O Complexo 1 apresenta ainda interações intermoleculares do tipo [N(3)-H(3) --- S(1)
= 3,5838(17)º, N(3)-H(3A) --- S(1) = 160,91(19)º], formando estruturas dímeras e ligação de
hidrogênio intramolecular não-clássica do tipo [C(10)-H(10) --- N(2) = 2,838(2)º e C(10) -
H(10) --- N(2) = 122º].
A estrutura cristalina do complexo 2, apresenta duas formas independentes (uma
com centro representado por Pb1 e outra por Pb2). Para a unidade com Pb1 temos o
complexo composto por duas unidades do Ligante 5, que comportam-se como quelantes
tridentados, e a esfera de coordenação é completada por interações intermoleculares do tipo
n2 areno TT e através da ligação polarizada com o O1 da moléculas vizinha, o que confere ao
íon Pb1 NC=9. A unidade Pb2 apresenta apenas as duas unidades do Ligante 5
coordenadas conferindo-lhe NC=6. A estrutura cristaliza no sistema monoclinico, grupo
espacial C2/c, parâmetros de cela a = 37,9747(6) A, b= 9,51280(10) A, c= 31,4378(5) A, ß =
125,951(2)°, V= 9193,5(2) A3, Z = 4, índices de discordância finais= R1 = 0,0643, wR2 =
0,1227.
This research shows the synthesis and characterization of five ligands and four derived from oximes and thiosemicarbazones. I crystalline/molecular structures determined by X-ray difraction in monocrystals: the ligand 4- phenylthiosemicarbazone-isatin (Ligand 5), the complexes pyridine-salicylaldehyde-4- phenylthiosemicarbazone of Ni(II) (Complex 1), and the bis-4-phenylthiosemicarbazone- isatin the Pb(II) (Complex 2). The structure of Ligand 5 crytallizes in the monoclinic system, space group P21/c, with the cell parameters a=6,3227(2) A, b=15,7973(7) A, c=14,4572(6) Å, ß= 93,9330(10)°, V=1440,61(10) A3 , Z=4. The refinement of the structure converges to the final discordance indexes R1 = 0,0520, wR2 = 0,1471. We have also observed the occurrence of intermolecular interactions of the type classic hydrogen bonds [N18-H3 .-. O1' 2,907(2)A], with the formation of dymer structures interrelated by symmetry within the crystalline cell. In the crystal structure of Complex 1, I have observed NC=4, and square plane coordination geometrics, where the ligand salicyladehyde-4-phenilsemicarbazone behaves as the tridentate quelating. In order to complete the coordenation sphere of the metallic center, there is a pyridine molecule. The structure crystallizes in the monoclinic system, space group P21/m, with cell parameters a = 12,8211(2) Å, b = 5,73370(10) Å, c = 23,9950(4) A, ß = 101,0910(10)°, V = 1730,98(5) A3, Z=3, and final discordance indexes R1= 0,0320, wR2= 0,0888. Complex 1 presents intermolecular interactions of the type [N(3)-H(3) --- S(1) = 3,5838(17)º, N(3)-H(3A) --- S(1) = 160,91(19)º], forming dymer structures and non-classic intramolecular hydrogen bonds of the type [C(10)-H(10) --- N(2) = 2,838(2)º and C(10) - H(10) --- N(2) = 122°]. The crystalline structure of Complex 2 presents two independent forms (one with the center represented by Pb 1 and another represented by Pb2). For unit Pb, there is the compound formed by two units of Ligand 5 which behaves as the tridentate quelating, and the coordination sphere is completed by intermolecular interactions of the type n2-arene TT and by a bond polarized with the O1 of the neighbouring molecule; it gives NC=9 to ion Pb1. Unit Pb2 presents just the two coordinated units of Ligand 5 giving it NC=6. The structure crystallizes in the monoclinic system, space group C2/c, cell parameters a=37,9747(6) Å, b= 9,51280(10) A, c= 31,4378(5) A, ß = 125,951(2)°, V= 9193,5(2) A3, Z=4, and final discordance indexes R1 = 0,0643, wR2 = 0,1227.
This research shows the synthesis and characterization of five ligands and four derived from oximes and thiosemicarbazones. I crystalline/molecular structures determined by X-ray difraction in monocrystals: the ligand 4- phenylthiosemicarbazone-isatin (Ligand 5), the complexes pyridine-salicylaldehyde-4- phenylthiosemicarbazone of Ni(II) (Complex 1), and the bis-4-phenylthiosemicarbazone- isatin the Pb(II) (Complex 2). The structure of Ligand 5 crytallizes in the monoclinic system, space group P21/c, with the cell parameters a=6,3227(2) A, b=15,7973(7) A, c=14,4572(6) Å, ß= 93,9330(10)°, V=1440,61(10) A3 , Z=4. The refinement of the structure converges to the final discordance indexes R1 = 0,0520, wR2 = 0,1471. We have also observed the occurrence of intermolecular interactions of the type classic hydrogen bonds [N18-H3 .-. O1' 2,907(2)A], with the formation of dymer structures interrelated by symmetry within the crystalline cell. In the crystal structure of Complex 1, I have observed NC=4, and square plane coordination geometrics, where the ligand salicyladehyde-4-phenilsemicarbazone behaves as the tridentate quelating. In order to complete the coordenation sphere of the metallic center, there is a pyridine molecule. The structure crystallizes in the monoclinic system, space group P21/m, with cell parameters a = 12,8211(2) Å, b = 5,73370(10) Å, c = 23,9950(4) A, ß = 101,0910(10)°, V = 1730,98(5) A3, Z=3, and final discordance indexes R1= 0,0320, wR2= 0,0888. Complex 1 presents intermolecular interactions of the type [N(3)-H(3) --- S(1) = 3,5838(17)º, N(3)-H(3A) --- S(1) = 160,91(19)º], forming dymer structures and non-classic intramolecular hydrogen bonds of the type [C(10)-H(10) --- N(2) = 2,838(2)º and C(10) - H(10) --- N(2) = 122°]. The crystalline structure of Complex 2 presents two independent forms (one with the center represented by Pb 1 and another represented by Pb2). For unit Pb, there is the compound formed by two units of Ligand 5 which behaves as the tridentate quelating, and the coordination sphere is completed by intermolecular interactions of the type n2-arene TT and by a bond polarized with the O1 of the neighbouring molecule; it gives NC=9 to ion Pb1. Unit Pb2 presents just the two coordinated units of Ligand 5 giving it NC=6. The structure crystallizes in the monoclinic system, space group C2/c, cell parameters a=37,9747(6) Å, b= 9,51280(10) A, c= 31,4378(5) A, ß = 125,951(2)°, V= 9193,5(2) A3, Z=4, and final discordance indexes R1 = 0,0643, wR2 = 0,1227.
Descrição
Dissertação (Mestrado)
Palavras-chave
Compostos de coordenação, Ligações de hidrogênio, Oximas, Tiossemicarbazonas, Coordination compounds, Hydrogen bonds, Oximes, Thiosemicarbazone
Citação
PERES, Gisele Louro. Síntese e caracterização de ligantes oximas e tiossemicarbazonas e seus complexos. 2009. 131 f. Dissertação (Mestrado em Química Tecnológica e Ambiental) - Programa de Pós-graduação em Química Tecnológica e Ambiental, Escola de Química e Alimentos, Universidade Federal do Rio Grande, Rio Grande, 2009.