Integration of Trinuclear Triangle Copper(II) Secondary Building Units in Octacyanidometallates(IV)-Based Frameworks

Abstract

The design and synthesis of high-dimensional materials based on secondary building blocks (SBUs) play a pivotal role in the further development of functional molecular materials. Herein, the self-assembly of Cu­(II) ions, pyrazole (Hpz), and octacyanidometallate­(IV) anions in the presence of water produced two new isostructural three-dimensional systems {[Cu3(μ3-OH)­(μ-pz)3(H2O)3]2[M­(CN)8]}·nH2O (M = W, 1, and Mo, 2). 1 and 2 consist of trinuclear triangle copper­(II) (TTC) SBUs and octacyanidometallates­(IV). At room temperature, both assemblies display strong antiferromagnetic interactions within the TTC entities with an average CuII···CuII isotropic magnetic coupling constant of about −145 cm–1. Moreover, a detailed analysis of magnetic data revealed the presence of spin frustration with antisymmetric magnetic exchange-coupling constants of around +32 and +46 cm–1 for 1 and 2, respectively. Finally, quantum chemical calculations explained their magnetic and optical properties.

Multi-d-Occupancy as an Alternative Definition for the Double d-Shell Effect

“…Only a hand full of data regarding the electronic structure of these systems can be found in the literature. To our knowledge, besides some experimental/theoretical hybrid works that use density functional theory, , there are only three works that employ theoretical methods considered highly accurate, − conducted by de Graaf et al using a model system of the magnetic photoswitch synthesized by Herrera et al…”

“…Only a hand full of data regarding the electronic structure of these systems can be found in the literature. To our knowledge, besides some experimental/theoretical hybrid works that use density functional theory, 4,5 there are only three works that employ theoretical methods considered highly accurate, 6−8 conducted by de Graaf et al using a model system of the magnetic photoswitch synthesized by Herrera et al 1 One of the limitations when describing such a series of compounds comes from the large system size. This is particularly the case when the wave function-based methods are necessary due to their unfavorable scaling with the number of electrons and basis set.…”