화학공학소재연구정보센터
Inorganic Chemistry, Vol.38, No.26, 6240-6245, 1999
Cyclopentadienyl behavior of pyrrolyl anions within the meso-octaethylporphyrinogen-binding lanthanides: Carbon-hydrogen and metal-carbon bond rearrangements
The complexation of Ln(III) ions by the meso-octaethylporphyrinogen [Et8N4H4]. 1. has been achieved by reacting the sodium derivative [Et8N4Na4. THF3], 2, with [LnCl(3). THF2]. Depending on the reaction or crystallization solvent, a variety of structural categories of Ln-porphyrinogen complexes have been isolated and structurally characterized. When the reaction was carried out in TNF and the final complex recrystallized from THF, [{(eta(5):eta(1):eta(5):eta(1)-Et8N4)-Ln(THF)}-eta(3)-Na(THF)(2)] complexes [Ln = Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Yb,(8)1 were obtained in a monomeric form, When their recrystallization was performed in dioxane, a dimerization occurred thanks to dioxane bridging the sodium cations of the monomeric units [{(eta(5):eta(1):eta(5):eta(1)-Et8N4)Ln(DME)}-eta(3)-Na](dioxane)(1.5)] [Ln = Nd, 14; Ln = Sm, 15]. In a third category we isolated complexes where two monomeric monoanions [(eta(5):eta(1):eta(5):eta(1)-Et8N4)Ln](-) are eta(2):eta(3) sandwiching two sodium cations, which are exclusively solvated by the pyrrolyl anions [{(eta(5):eta(1):eta(5):eta(1)-Et8N4)Ln}(2)-eta(2):eta(3)-Na-2] [Ln = Pr, 16; Ln = Sm, 17]. The three classes of compounds mentioned above, all of them containing the monomeric unit [Ln-porphyrinogen-Na], are characterized by the following structural parameters: Ln-eta(5)(pyrrole)(av) 2.490(7) Angstrom for 7, 2.556(2) Angstrom for 14, 2.543(2) Angstrom for 16; Ln-eta(1)(pyrrole)(av), 2.43(1) Angstrom for 7, 2.494(4) Angstrom for 14, 2.485(4) Angstrom for 16; centroid-Ln-centroid, 174.6(3)degrees for 7, 168.1(1)degrees for 14, 169.7(2)degrees for 16: Na-eta(3)(pyrrole), 2.50(1) Angstrom for 7, 2.515(3) Angstrom for 14. The recrystallization of complexes 3-8 from DME led to dimeric organometallic complexes, where the dimerization has beets via the desolvation of the Ln ion and the formation of a Ln-C sigma bond with the beta-carbon of a pyrrole of an adjacent Ln-porphyrinogen unit. Such dimers occur in the ion-separated form [(eta(5):eta(1):eta(5):eta(1)-Et8N4)(2)Ln(2)][NaSn](2) [Ln = Pr (9), Nd (10), Sm (II), Gd (12), Eu (13)1. Their recrystallization from THF led to the ion-pair derivatives in which two sodium cations are eta(2)-bonded to the eta(1)-pyrrolyl anions of the dimer [{(eta(5):eta(1):eta(5):eta(1)-Et8N4)(2)Ln(2)}-eta(2)(NaSn)(2) [Ln = Pr (18), Nd (19), Sm (20), Gd (21); S = DME, TNF; n = 2]. When the crystallization of 9-13 was carried out from THF/dioxane, polymeric structures were isolated, where cations are bridged by dioxane molecules [{(eta(5):eta(1):eta(5): eta(1)-Et8N4)(2)Ln}(2)-eta(2){Na(THF)}(2)(mu-dioxane)][Ln = Nd, 22; Ln = Gd, 23]. In the three classes made up from the dimeric building block, the structural leit-motiv is constant and two structural parameters are very close [Ln-eta(5)(pyrrole)(av), 2.538(3) Angstrom for 11, 2.578(1) Angstrom for 18; centroid-Ln-centroid, 172.3(2)degrees for 11, 170. 4(1)degrees for 18; Ln-C, 2.471(7) Angstrom for 11, 2.512(2) Angstrom for 18].