화학공학소재연구정보센터
Inorganic Chemistry, Vol.52, No.4, 1926-1941, 2013
Indolenine meso-Substituted Dibenzotetraaza[14]annulene and Its Coordination Chemistry toward the Transition Metal Ions Mn-III, Fe-III, Co-II, Ni-II, Cu-II, and Pd-II
A new dibenzotetraaza[14]annulene bearing two 3,3-dimethylindolenine fragments at the meso positions (LH2), has been synthesized through a nontemplate method. X-ray crystallography shows that the whole molecule is planar. The basicity of the indolenine ring permits the macrocycle to be protonated external to the core and form LH42+center dot 2Cl(-). Yet another structural modification having strong C-H center dot center dot center dot pi interactions was found in the chloroform solvate of LH2. The latter two modifications are accompanied by a degree of nonplanar distortion. The antiaromatic core of the macrocycle can accommodate a number of metal ions, Mn-III, Fe-III, Co-II, Ni-II and Cu-II, to form complexes of [Mn(L)Br], [Mn(L)Cl], [Fe(LH2)Cl-2](+)center dot Cl-, [Co(L)], [Ni(L)], and [Cu(L)]. In addition, the reaction of LH2 with the larger Pd-II ion leads to the formation of [Pd-2(LH2)(2)(OAc)(4)] wherein the macrocycle acts as a semiflexible ditopic ligand to coordinate pairs of metal ions via its indolenine N atoms into dinuclear metallocycles. The compounds LH2, [Co(L)], and [Ni(L)] are isostructural and feature close pi-stacking as well as linear chain arrangements in the case of the metal complexes. Variable temperature magnetic susceptibility measurements showed thermally induced paramagnetism in [Ni(L)].