title: 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.
abstract: Co(II) and Zn(II) ions exhibit variable reactivity toward O-containing ligands in aqueous media, affording isolable materials with distinct solid-state lattice properties. d-(-)-quinic acid is a cellular α-hydroxycarboxylate metal ion binder, which reacts with Co(II) and Zn(II) under pH-specific hydrothermal conditions, leading to the isolation of two new species [Co(2)(C(7)H(11)O(6))(4)](n)·nH(2)O (1) and [Zn(3)(C(7)H(11)O(6))(6)](n)·nH(2)O (2). Compound 1 was characterized by elemental analysis, spectroscopic techniques (FT-IR, UV-visible, EPR), magnetic studies, and X-ray crystallography. Compound 2 was characterized by elemental analysis, spectroscopic techniques (FT-IR, ESI-MS), and X-ray crystallography. The 2D molecular lattices in 1 and 2 reveal the presence of octahedral M(II) units bound exclusively to quinate in a distinct fashion, thereby projecting a unique chemical reactivity in each investigated system. The magnetic susceptibility and solid-state/frozen solution EPR data on 1 support the presence of a high-spin octahedral Co(II) in an oxygen environment, having a ground state with an effective spin of S = 1/2. Concurrent aqueous speciation studies on the binary Zn(II)-quinate system unravel the nature and properties of species arising from Zn(II)-quinate interactions as a function of pH and molar ratio. The physicochemical profiles of 1 and 2, in the solid state and in solution, earmark the importance of (a) select synthetic hydrothermal reactivity conditions, affording new well-defined lattice dimensionality and nuclearity M(II)-quinate materials, (b) structural speciation approaches delineating solid state-aqueous solution correlations in the binary M(II)-quinate systems, and (c) pH-specific chemical reactivity in binary M(II)-quinate systems reflecting structurally unique associations of simple aqueous complexes into distinctly assembled 2D crystalline lattices.
authors.affiliation: Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.
authors.forename: M
authors.initials: M
authors.lastname: Menelaou
authors.forename: A
authors.initials: A
authors.lastname: Konstantopai
authors.forename: N
authors.initials: N
authors.lastname: Lalioti
authors.forename: C P
authors.initials: CP
authors.lastname: Raptopoulou
authors.forename: V
authors.initials: V
authors.lastname: Psycharis
authors.forename: A
authors.initials: A
authors.lastname: Terzis
authors.forename: C
authors.initials: C
authors.lastname: Mateescu
authors.forename: K
authors.initials: K
authors.lastname: Tsarhopoulos
authors.forename: P
authors.initials: P
authors.lastname: Rigas
authors.forename: A
authors.initials: A
authors.lastname: Salifoglou
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D011199:Potentiometry; D011801:Quinic Acid / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D053719:Tandem Mass Spectrometry; D015032:Zinc / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D011801:Quinic Acid; D003035:Cobalt; D015032:Zinc