脂氧合酶模型化合物[Fe(CTB)Cl]Cl·3CH_3CH_2OH·H_2O的合成、晶体结构与氧化活性

Synthesis, Crystal Structure and Oxidation Activity of Lipoxygenase Model Compound [Fe(CTB)Cl]Cl·3CH_3CH_2OH·H_2O

合成了含F e2+的脂氧合酶模型化合物[F e(CTB)C l]C l.3CH3CH2OH.H2O(CTB为N,N,N,′N′-四(2′-苯并咪唑甲基)邻二胺反式-环己烷).该配合物属单斜晶系,P 21/n空间群.晶胞参数a=1.129 38(7)nm,b=1.490 04(9)nm,c=2.693 46(17)nm,β=91.953 0(10),°V=4.530 0(5)nm3,Z=4;R=0.060 2,wR=0.162 9.中心离子F e2+只与六齿配体CTB的3个苯并咪唑的3-位氮和两个烷胺氮配位,氯离子占据着第六配位位点,整个配合物呈变形八面体构型.该化合物可催化亚油酸氧化断链成丙二醛(酸)、壬烯醛和壬醛酸等低分子醛和ω-氧酸.

A novel lipoxygenase model compound, Cl·3CH-3CH-2OH·H-2O was synthesized and characterized(CTBN,N,N′,N′-tetrakis(2′-benzimidazolylmethyl)-ortho-diamine trans-cyclohexane). The single crystal X-ray analysis shows that this compound crystallizes in the monoclinic system, space group P2-1/n with cell parameters a1.129 38(7) nm, b1.490 04(9) nm, c2.693 46(17) nm, β9.195 30(10)°, V4.530 0(5) nm+3, and Z4; R0.060 2, wR0.162 9. It is interesting that the iron(Ⅱ) ion is bonded to three benzimidazolyl nitrogens(the average bond distance of {Fe_N} is {0.206 4} nm) and two amino nitrogens(the bond distances of Fe_N are 0.218 9 and 0.229 1 nm, respectively) of ligand CTB, there is an uncoordinating benzimidazolyl group expanding in the space, the sixth position is coordinated by one chloride ion(the bond length of Fe_Cl is 0.237 25 nm). So the title complex shows a distortedly octahedral coordination. Following the reaction of oxidative products with thiobabituric acid indicates that the complex can enhance linoleic acid oxidation. Electrospray ionization mass-spectrum in positive ion mode(ESI+) shows that linoleic acid is oxidatively cleft resulting in volatile small molecular fragments, such as malondialdehyde, nonanal, nonenal, malonic acid, hydroxy ethanal and nonanal acid, etc. These aldehydes and ω-oxo acids are important phytoalexins, which can induce biosynthesis of numerous compounds, proteins and enzymes in physiological and pathological signaling systems.