Carboxylate Coordination Assisted Aggregation for Quasi‐Tetrahedral and Partial‐Dicubane [Cu₄] Coordination Clusters

Abstract

The reaction of three copper(II) carboxylate (R = Me, Ph and H in RCO2−) salts in MeOH with H3L resulted three [Cu4] aggregates: [Cu4(μ4‐O)(μ‐H2L)2(μ1,3‐O2CCH3)4] (1), [Cu4(μ4‐O)(μ‐H2L)2(μ1,3‐O2CPh)(PhCO2)3]⋅H2O (2⋅H2O), and [Cu4(μ3‐OH)2(μ‐H2L)2(μ1,1‐HCO2)2(HCO2)2]⋅2H2O (3⋅2H2O). Three different carboxylate groups showing varying coordination modes were responsible for the self‐aggregation of two ligand bound [Cu2(H2L)]3+ units. The [Cu4O] and [Cu4(OH)2] cores were generated from water‐derived oxido and hydroxido nucleating groups to provide quasi‐tetrahedral and partial‐dicubane topologies. In complexes 1 and 2⋅2H2O the μ1,3 bridging mode of the carboxylate bridges were responsible for the entrapment of μ4‐O unit, whereas μ1,1 bridge by formato groups resulted in trapping of two μ3‐OH units in complex 3⋅2H2O. Complex 3⋅2H2O is the first reported example of a μ1,1‐formato bridged [Cu4] aggregate. Long range van der Waals forces, in presence of hydrogen bonding interactions, also play significant role in the [Cu4] aggregation process. These have been analyzed by DFT calculations and Hirshfeld surface analysis.

Synthesis and Investigation of Solid‐ and Solution‐State Structures of Nickel(II) Complexes with 1,3‐Dimethyl‐5‐(arylazo)‐6‐aminouracil

“…It is also worth mentioning that supramolecular chemists usually analyze the intermolecular interactions in X‐ray structures that are shorter than the sum of the van der Waals radii; longer interactions in the crystal structures are not generally investigated. Clearly, this is a relatively simplistic view of crystal packing, because interactions slightly longer than the van der Waals radii also have an impact . Taking this into account, in this theoretical study we wish to exemplify the contribution of the long‐range interactions in C–H/π bonded assemblies retrieved from the solid‐state structure of [Ni II ( 1 ) 2 ] reported herein.…”

Investigations on a mononuclear Cu(ii) Schiff base complex: theoretical calculations, catechol oxidase activity, and protein binding interaction analysis

“…This shifting of the imine stretching frequency value to lower wavenumber in complex 1 was due to the donation of lone-pair electrons from ligand imine nitrogen atom to the vacant d-orbital of the Cu(II) ion. 3,13,75,93 The Cu 2+ -bound phenoxido oxygen stretching frequency n (Cu-O/ring stretch) appeared as a weak peak at 861 cm À1 . 94 Electronic spectra of ligand H 2 L and complex 1 displayed several representative bands in the 200-800 nm range in MeCN solution.…”

“…The red spots in the graphical plot specified shorter contacts while the white areas highlighted contacts around the van der Waals distance, and the blue color regions indicated longer contacts. d norm = {( d i − r i vdw )/ r i vdw } + {( d e – r e vdw )/ r e vdw }where d i and d e represent the distance between the surface and the nearest internal atom and external atom, respectively, whereas r vdW i and r vdW e are the van der Waals radii of the nearest internal atom to the surface and external atom to the surface, respectively. 75,76 One more important property of curvedness was also evaluated based on the local curvature of the surfaces of complex 1 . A 2D fingerprint plot was also generated to obtain the unique visualization of various intermolecular interactions.…”

“…where d i and d e represent the distance between the surface and the nearest internal atom and external atom, respectively, whereas r vdW i and r vdW e are the van der Waals radii of the nearest internal atom to the surface and external atom to the surface, respectively. 75,76 One more important property of curvedness was also evaluated based on the local curvature of the surfaces of complex 1. A 2D fingerprint plot was also generated to obtain the unique visualization of various intermolecular interactions.…”

Two-dimensional lanthanide coordination polymer nanosheets for detection of FOX-7

“…† The existence of domain peaks in L$Eu and L$Tb at 2q ¼ 24.91 and 23.70 with d-spacing values of 3.57 and 3.75Å, respectively, was in agreement with the presence of intermolecular p/p stacking interactions in those CPs. 35,36 The L$Eu and L$Tb nanosheets were prepared by liquid exfoliation of their corresponding bulk powder through a topdown sonication assisted strategy, where the bulk layered materials cleaved into few-layered 2D nanosheets (Scheme 1). It was found that chloroform-tetrahydrofuran (1 : 1, v/v) and acetonitrile are ideal solvent systems for the exfoliation of L$Eu and L$Tb bulk powder among the wide range of solvents with different polarities that were tested.…”