Ligand-Templated Four-Metal Chains Dimerize into a Unique [CuII8] Cluster

Abstract

A space‐ship‐like Cu8 cluster (see picture) results from the linking of two linear [Cu$\rm{^{II}_{4}}$] units previously assembled through the template action of a pentadentate O ligand. The core of the cluster represents an entirely new topology within the vast family of magnetically coupled Cu aggregates. The alkoxide‐bridged octanuclear units are connected to each other by nitrate ligands into an unprecedented cluster polymer.

Zn(II) and Co(III) metallosupramolecular assemblies derived from a rigid bis-Schiff base ligand

“…The design and construction of high-nuclearity metal-organic cluster complexes through the implementation of predesigned multidentate organic ligands have received considerable attention in the past decades [1][2][3][4][5], owing to their remarkable physical and chemical properties that promise extensive applications in catalysis, molecular sensing, biological systems as well as magnetic and opto-electronic materials [6][7][8][9][10][11][12][13][14][15][16][17][18]. The Schiff base condensation between aldehydes/ketones and amines has proven to be one of the most convenient pathways to approach multidentate ligands with excellent capability of metal complexation that have been frequently employed to construct high-nuclearity metallosupramolecular assemblies [11][12][13][14][15][16].…”

“…of Co(OAc) 2 ·2H 2 O in a solution of CH 2 Cl 2 -MeOH mixture resulted in the isolation of purple crystals (3) after slow evaporation of the reaction mixture at room temperature over two weeks. The high-resolution ESI mass spectrum clearly revealed the formation of a molecular composition of Co 2 (L)3 , which differs obviously from the previous zinc(II) assemblies. The spectrum exhibits peak envelopes at m/z 1097.2524 and 1119.2327 that can be assigned to [M + H] + and [M + Na] + , respectively, consistent with the presence of a bimetallic tris-ligand neutral complex in solution.…”

Chiral tetranuclear and dinuclear copper(ii) complexes for TEMPO-mediated aerobic oxidation of alcohols: are four metal centres better than two?

“…[12][13][14][15][16][17] However, the types of organic ligands exploited in the copper catalyst systems are still limited and the structures of copper catalysts involved in the catalytic process are rarely explored. [17][18][19][20] The construction of metal-organic cluster compounds through self-assembly of predesigned ligands with appropriate metal ions is a prime research topic [21][22][23][24][25] due to the advantages in catalysing useful chemical transformations, in contrast to simple monometallic complexes. [26][27][28][29][30] Schiff base type ligands are excellent ligand candidates for high-nuclearity metallosupramolecular assemblies, in particular in cases where additional O-donor atoms have been introduced to the backbone of a Schiff base ligand scaffold.…”

“…12-17 However, the types of organic ligands exploited in the copper catalyst systems are still limited and the structures of copper catalysts involved in the catalytic process are rarely explored. [17][18][19][20] The construction of metal-organic cluster compounds through self-assembly of predesigned ligands with appropriate metal ions is a prime research topic [21][22][23][24][25] Herein, we report the one-pot syntheses and crystal structures of two tetranuclear and dinuclear copper(II) complexes resulting from the in situ synthesis of chiral Schiff base ligands (Scheme 1), and their catalytic applications in the TEMPO-mediated aerobic oxidation of benzylic alcohols. The catalytic potential of two complexes is compared based on their catalytic performance in various alcohol oxidation reactions, suggesting that the copper(II) complex with a Cu 4 core is a more efficient catalyst than that one having a Cu 2 core.…”

Di- and trinuclear CoIIcomplexes of a bis-β-diketone ligand with variable conformation: structure and magnetic studies

“…7 Ligands of the polyb-diketone type constitute a growing family of donors, some of which have allowed the formation of polynuclear transition metal clusters with interesting topologies and properties as well as coordination polymers featuring attractive extended architectures. [8][9][10][11] One of our goals for some years has been to develop synthetic methods for the preparation of new polyb-diketone species, including phenol groups in their structure as additional potential donors, in order to exploit their coordination properties. 12,13 One of these ligands (H 3 L, Scheme 1) contains two b-diketone groups separated by one phenol functionality, so as to display an array of five oxygen donors disposed in a linear manner, thus enabling four adjacent coordinating pockets to chelate simultaneously an equal number of metals in close proximity (top left in Scheme 2).…”