Fascinating Structures of a Mixed Valence [Mn^III]·[Mn^IIMn^III] Cocrystal and a Mn^IIINa^IComplex: Slow Magnetic Relaxation and Theoretical Investigations

Abstract

Herein, a cocrystal, incorporating mixed valence manganese ions, namely, [MnIII]·[MnIIMnIII] formulated as [{MnIII(Vaan)2}­·{MnIIMnIII(Vaan)2(H2O)3}­·14H2O] (1) and a MnIIINaI compound {MnIIINaI(Vaan)2­(H2O)2}­·H2O] (2), are synthesized utilizing MnII precursor salts and a rarely used ligand, 2-[(2-hydroxy-3-methoxy-benzylidene)-amino]-benzoic acid (H2Vaan). Structure analyses illustrate that 1 contains a cationic dinuclear unit (MnIIMnIII) and an anionic mononuclear unit MnIII to generate the cocrystal, whereas a different recipe produces compound 2. Detailed descriptions of the prevailing supramolecular interactions within the systems have been provided. Interestingly, as far our knowledge goes, 1 is the first example of a cocrystal involving a mixed valence MnII/MnIII species. Notably, dc and ac susceptibility measurements indicate the existence of slow relaxation of magnetization in both complexes. Furthermore, we have analyzed the nature of the magnetic interactions present using density functional theory based on the CASSCF-NEVPT2 methodology

Tuning Dimensions of Complexes through Selective In Situ Reaction, Mechanistic Insights into Ni(II)-Catalyzed Br–OH Exchange, Magnetic Properties, and Density Functional Theory Studies

“…In principle, magnetic coupling exhibits the spin delocalization effect from Mn­(II) atoms to the bridging atoms. Here, spin delocalization is observed for the trinuclear Mn­(II) unit, in which the Mn2, Mn1, and Mn1A ions in HS display spin densities of 3.899, 3.843, and 2.847, respectively (Figure a), whereas in BS corresponding to −3.915, 3.852, and 2.841 (Figure b), and these values are lower than the previously reported values, resulting in weak antiferromagnetic interactions. Additionally, the magnetic coupling approach is dominated by σ-type orbital overlaps between the metal ions and the hybrid orbitals of the bridging oxygen atoms; in other words, the overlap integrals S from 0.00778 to 0.05322, where the α spin density is localized on Mn­(II) ions, similarly show weak antiferromagnetic interactions (Figure S9).…”

A 3D-Coordination Polymer Assembled from Copper Propionate Paddlewheels and Potassium Propionate 1D-Polymeric Rods Possessing a Temperature-Driven Single-Crystal-to-Single-Crystal Phase Transition

“…Moreover, the preparation of highly crystalline products, especially X-ray-quality single crystals, is often a serious challenge. − In contrast, s and f cations readily form well or moderately soluble coordination polymers upon interaction with the majority of ligands, even with β-diketonates − and simple aliphatic carboxylates, − under much milder conditions: for instance, upon isothermal crystallization of solutions, ,, which is rather convenient for the preparation of bulk samples and crystal growth. Furthermore, there are a few examples of s–d, − f–d, and even s–f heterometallic carboxylates where large cations (s or f) often coordinate d metal containing species as ancillary ligands. Among those, polymeric structures exist as well; nevertheless, the majority of them were obtained serendipitously.…”

Self-assembling of three rare structurally various homomultinuclear CuII complexes derived from a bis(salamo)-based multioxime ligand

“…Coordination chemistry is an important branch of chemistry and is involved many active research fields (Mirza et al, 2018;Liu et al, 2018aLiu et al, , 2019cYamamura et al, 2010;Wang et al, 2012;Duan et al, 2019;Zhang et al, 2020b;Cao et al, 2017). In salen-based ligands [R-CH N-(CH 2 ) n -N CH-R] and their corresponding homometallic and heterometallic complexes, due to their potential application values, intense research in modern coordination chemistry is still ongoing (Bhanja et al, 2020;Maity et al, 2020;Bag et al, 2020;Song et al, 2018;Majumdar et al, 2018;Zhang et al, 2015;Wang et al, 2009;Lo Presti et al, 2010). Therefore, the construction of novel and functional metal complexes has become a research hotspot of the salen-based ligands (Mü ller et al, 2017;Li et al, 2017Li et al, , 2018bFeng et al, 2012).…”