Pentaaza macrocyclic ytterbium(iii) complex and solvent controlled supramolecular self-assembly of its dimeric μ-η²:η²peroxo-bridged derivatives

Abstract

The unprecedented template action of ytterbium ion in the synthesis of pentaaza macrocyclic Schiff bases is exemplified by isolation and definitive identification of the seven-coordinate pentagonal bipyramidal complex with the formula of [YbLCl(2)]ClO(4) (1), where L is 2,14-dimethyl-3,6,10,13,19-pentaazabicyclo[13.3.1]nonadeca-1(19),2,13,15,17-pentaene, providing the first example of crystallographically characterized pentaaza macrocyclic ytterbium complex. For the first time the spectrum of the (2)F(7/2) --> (2)F(5/2) transition has been obtained for a molecular complex of ytterbium with organic ligands in which all ligand-field components of the ground and excited state are well displayed at room temperature. This complex is capable of forming a dimeric peroxo Yb(2)(mu-eta(2):eta(2)-O(2))L(2)(4+) (2) derivative containing the biologically significant planar side-on doubly bidentate coordination mode of the peroxide. Inclusion of the appropriate solvent molecule into the crystal structure generates supramolecular architectures (2a-d) in which the solvent controlled self-assembly is observed. Spectral properties of these complexes were found to be very important and promising in the area of ytterbium physicochemistry.

Self‐Assembled Lanthanide Salicylaldimines with a Unique Coordination Mode

“…The reflectance spectrum of the Yb 3+ -H 2 L complex shown in Figure 5 was used for the energy level determination of the 2 F 7/2 Ǟ 2 F 5/2 transition. The position of the 2 F 5/2 (0) level equal to 10228 cm -1 is redshifted in comparison to those previously found by us for pentaaza macrocyclic [12] and carboxylic [13] ytterbium complexes. The splitting of the 2 F 5/2 manifold by the ligand field in the current compound was determined as 0, 148, and 378 cm -1 .…”

Quaterpyridine Ligands Forming Helical Complexes of Mono‐ and Dinuclear (Helicate) Forms

“…If these are the factors responsible for the adoption of a centrosymmetric space group by crystals of 7, then it may be that the resolution of helicates can be controlled by the size of the anion relative to that of the cation. [29] and to evaluating any anion effects. The crystal-structure determinations (Table 1), discussed in detail below, show that the anions have no marked influences on the form of the bound ligand, which is nonplanar and perceptibly helical in all cases.…”

Self-assembly as a route to dinuclear lanthanide complexes with rare coordination pattern of salen-type ligand

“…Compared with d-electron elements, the potential of lanthanide ions in the rational design and synthesis of well-defined supramolecular architectures has been less exploited due to the difficulty in controlling the coordination environments of these ions which display high and variable coordination numbers with little stereochemical preferences. Many interesting supramolecular structures involving the lanthanides are sometimes unexpected and cannot be predicted [9][10][11][12][13][14][15][16]. However, their retrospective analysis may provide necessary information in the attempts at intentional design of new materials with specific functions and properties.…”