In Search of Binary Hybrid Systems in Manganese Chemistry: The Synthesis, Spectroscopic and Structural Characterization, and Magnetic Properties of a New Species in the Aqueous Mn^II‐Quinic System

Abstract

Manganese is a metal with diverse (bio)chemical reactivity in aqueous media in the presence of biologically relevant ligands. Key to that reactivity is the existence of soluble and bioavailable forms of Mn II across the physiological range of pH. To probe the interactions arising between Mn II and the low-molecular-mass ligand D-(-)-quinic acid, research efforts were targeted at the synthetic aqueous chemistry in the requisite binary system. The pH-specific synthetic reaction of Mn II with D-(-)-quinic acid led to the isolation of the new species [Mn 2 (C 7 H 11 O 6 ) 4 ] n ·nH 2 O (1). Complex 1 was characterized by elemental analysis, spectroscopic techniques (EPR, FTIR), thermal and magnetic studies, and X-ray crystallography. The molecular lattice of 1 reveals the presence of dimeric units of Mn II centers, with the quinate ligands coordinated to the metal ions through variable binding modes, indicating the diversity of chemical reactivity in the system.

Hydrothermal Synthesis and Characterization of 2D M(II)-Quinate (M = Co,Zn) Metal−Organic Lattice Assemblies: Solid-State Solution Structure Correlation in M(II)-Hydroxycarboxylate Systems

“…The proposed speciation distribution for Zn(II) is in line with the corresponding speciation distributions previously observed in the case of Co(II) 35 and Ni(II). 53 Of the two species, the [ZnL 2 ] 0 complex reflects quite well the molecular stoichiometry of the species synthesized and isolated in the solid state (2). It could be envisioned that 2 may arise through substitution of the water molecules bound to Zn(II) in [ZnL 2 ] 0 by adjacently located similar units, utilizing the anchoring ability of the second oxygen terminal of the carboxylate group bound to Zn(II).…”

“…In this regard, 1 is the first of the Co(II)quinate family of species, where one of the protonated triol moieties plays a key role in the formation of polymeric species, similar to isostructural [Mn 2 (C 7 H 11 O 6 ) 4 ] n 3 nH 2 O. 53 In the latter case, however, no analogous aqueous transformation chemistry had been shown to link the dinuclear repeating unit with mononuclear partners of variable composition.…”

“…Zn(3)-O] found in 2, and they are in good agreement with the bond distances found in [Zn 3 (C 6 H 5 O 7 ) 2 (H 2 O) 2 ] n , 49 (NH 4 ) 4 [Zn(C 6 H 5 O 7 ) 2 ], 50 [Zn-(C 4 H 4 O 5 )(C 10 H 8 N 2 ) 3 3H 2 O] n, 51 [Zn(C 3 H 5 O 3 ) 2 (C 3 H 4 N 2 ) 2 ] 3 0.5H 2 O, and [Zn(C 4 H 7 O 3 ) 2 (C 3 H 4 N 2 ) 2 ] 52. Finally, compound 1 is isostructural with the metalorganic hybrid [Mn 2 (C 7 H 11 O 6 ) 4 ] n 3 nH 2 O 53. Also comparable are the M-O distances occurring in various quinate complexes such as K[Co(C 7 H 11 O 6 ) 3 ] 3 3CH 3 CH 2 OH, 35 Na[Co(C 7 H 11 O 6…”

Synthesis, Crystal Structures, and Magnetic Properties of MnII, CoII, and ZnII Coordination Polymers Containing 1,2,4,5‐Benzenetetracarboxylic Acid and 4,4′‐Azobispyridine

“…Upon cooling from 300 K, there is a slightly decrease in the value of χ M T close to 4.37 emu K mol -1 at 300 K to 4.31 emu K mol -1 at 50 K. With a further decrease in temperature, the value of the χ M T product decreases sharply, reaching a minimum value of 3.95 emu K mol For an infinite 2D square lattice composed of classical spins (S = 5/2) isotropically coupled, the theoretical magnetic susceptibilities is given by Equation (1). [41] ( 1) where N is Avogadro's constant, β is Bohr's magneton, k is Boltzmann's constant, and u is the well-known Langevin function [see Equation (2)]. The least-squares fitting of the magnetic susceptibility data led to J = -0.02 cm -1 and g = 1.99.…”

A novel two-dimensional homochiral manganese(II)-carboxylate coordination framework exhibiting field-induced spin-flop transition

“…The critical field H sf in 1 is of the same order of magnitude as that observed for the Mn(II) complex containing syn-anti carboxylate bridges. 15 In conclusion, a novel 2D layered network {[Mn(cpdba)-(H 2 O) 3 ]$H 2 O} n (1) has been successfully synthesized based on the unique asymmetric bridging ligand 4-(4-carboxyphenylamino)-3,5dinitrobenzoic acid (H 2 cpdba), which contains homochiral helical Mn(II) chains linked by syn-anti carboxylate bridges. The chirality of the stereochemically labile amine core in the H 2 cpdba ligand can be ''locked'' by the coordination bonds during the molecular assembly, and be consequently transferred throughout the entire coordination network.…”