Synthesis and structural characterization of lanthanide(III) texaphyrins

Abstract

The synthesis and characterization of several lanthanide(III) texaphyrin complexes of 4, 5, 9, 24-tetraethyl-16, 17-dimethoxy-10, 23-dimethyl-13, 20, 25, 26, 27-pentaazapentacyclo[20.2.1.1 heptacosa]-1, 3, 5, 7, 9, 11(27),-12, 14, 16, 18, 20, 22(25), 23-tridecaene (2), 4, 5, 9, 24-tetraethyl-16, 17-bis((3-hydroxypropyl)oxy)-10, 23-dimethyl-13, 20, 25, 26, 27-pentaazapentacyclo-[20.2.1.1] heptacosa-1,3, 5, 7, 9, 11(27), 12, 14(19), 15, 17, 20, 22(25),-20, 25, 26, 27-pentaazapentacyclo[20.2.1.1] heptacosa-1,3, 5, 7, 9, 11(27), 12, 14, 16, 18, 20, 22(25), 23-tridecaene (30), respectively, are reported. Single crystals suitable for X-ray diffraction were obtained for the La(III) complex 3, the Gd(III) complexes 9 and 37, the Eu(III) complex 36, and the Lu(III) complex 22, by dissolving the respective complex in MeOH/CHCl[sub 3] and layering with diethyl ether. The five lanthanide(III) texaphyrin complexes all crystallize in the triclinic space group, P[bar 1] (No. 2), with Z = 2. The complexes are characterized by five-coordination from the texaphyrin, a coordinated methanol molecule on one side and at least one symmetrically bidenate NO[sub 3][sup [minus]] ion opposite the methanol. The 10-coordinate La(III) complex 3 has two bidentate NO[sub 3][sup [minus]] ions on the same side of the macrocycle. The europium(III) and gadolinium(III) texaphyrins 36 and 37 are structurally isomorphous and are 9-coordinate species with a bidentatemore » NO[sub 3][sup [minus]] ion and a methanol molecule on the top side of the macrocycle. On the other hand, the lutetium(III) texaphyrin is 8-coordinate with only a single bidentate NO[sub 3][sup [minus]] ion chelated on the [open quotes]top[close quotes] side of complex. In an unusual case of disorder, the gadolinium(III) texaphyrin 9 has both 9- and 10-coordinate species present in the solid state. The geometry of the 9-coordinate species is like that found in 36 and 37, while the 10-coordinate Gd(III) species similar to the La(III) species 3.« less