Degradations of novel tetranuclear vanadyl glycollates to dinuclear species

Abstract

Novel tetranuclear vanadyl glycollates [Ni(phen) 3 ] 2 [V IV 4 O 4 (glyc) 6 ]•23H 2 O (1) and [Ni(phen) 3 ] 2 [V IV 4 O 4 (glyc) 6 ]•16H 2 O (2) have been obtained through the capture of bulky nickel phenanthroline cation (H 2 glyc = glycollic acid, phen =1,10-phenanthroline), and the mixed-ligand complex [V IV 4 O 6 (glyc) 2 (bpy) 4 ]•6H 2 O (3) (bpy = 2,2'-bipyridine) was isolated with the addition of bpy under hydrothermal condition. Tetrameric 1 and 2 are easily oxidized to dimeric complex [Ni(phen) 3 ][V V 2 O 4 (glyc) 2 ]•5H 2 O (4), while 3 with bipyridine is stable. The degradation process was traced by IR and XRD experiment. 1 ~ 4 feature bidentate glycollate that chelates to vanadium atom through α-alkoxy and α-carboxy groups, which were full characterized by elemental analysis, TG, IR, UV-vis, EPR, XRD and X-ray structural analyses. Bond valence calculation is also performed.

Isolated Mixed-Valence Iron Vanadium Malate and Its Metal Hydrates (M = Fe2+, Cu2+, Zn2+) with Reversible and Irreversible Adsorptions for Oxygen

“…The asymmetric stretching modes associated with CO 2 – functional groups of malates are present at 1664 and 1618 cm –1 for 1 , 1664 and 1580 cm –1 for 2 -Fe, 1667, 1651, 1644, and 1562 cm –1 for 3 -Cu, and 1667 and 1580 cm –1 for 4 -Zn, respectively. The symmetric stretching modes of CO 2 – groups are present at 1382 cm –1 for 1 , 1392, 1358, and 1342 cm –1 for 2 -Fe, 1384, 1361, and 1341 cm –1 for 3 -Cu, and 1385, 1361, and 1342 cm –1 for 4 -Zn, respectively. − The O–H stretching vibration for water molecules in 1 – 4 is observed as a broad and strong peak at around 3400 cm –1 . Additional peaks related to N–H and C–H vibrational modes are present around 3100–3300 and 2800–3000 cm –1 in 1 and 2 -Fe, respectively.…”

Preliminary Assignment of Protonated and Deprotonated Homocitrates in Extracted FeMo-Cofactors by Comparisons with Molybdenum(IV) Lactates and Oxidovanadium Glycolates

“…Most of the previous glycolate, lactate, malate, citrate, or homocitrate bind to vanadium or molybdenum via α-alkoxy and α-carboxy and/or β-carboxy groups, − while only a small number of complexes were isolated coordinating via α-hydroxy (protonated) and α-carboxy groups. ,− As the homocitrates in the cofactors have a bidentate coordination, protonated and deprotonated molybdenum/vanadium α-hydroxycarboxylates with the similar local structures are critical for comparisons with the FeMo/V-cos and for a better clarification of their coordination environments. In this publication, we report the successfully isolated protonated and deprotonated pair of mononuclear glycolato oxidovanadium complexes: [VO­(Hglyc)­(phen)­(H 2 O)]­Cl·2H 2 O ( 1 ) and [VO­(glyc)­(bpy)­(H 2 O)] ( 2 ) (H 2 glyc = glycolic acid, bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline).…”

Mixed‐Ligand Oxidovanadium(IV/V) Complexes Chelated by α‐Hydroxycarboxylate and 2‐(1H‐Imidazol‐2‐yl)pyridine: Localized Structures and Gas Adsorption

“…FT-infrared spectra of 1-4 in the regions of 2000-500 cm À 1 are given in Figure S3, with well-resolved strong and sharp absorption bands in 1-3 for the carboxy and/or carboxylic acidic groups of the coordinated citrate, malate and glycolate respectively. Strong absorption bands observed at 1687 cm À 1 for 1, 1631 cm À 1 for 2 [12] 1.862(4) 2.106(3) [V 2 O 3 (phen) 3 (S-lact)]Cl • 5.5H 2 O [12] 1.856(4) 2.071(4) [V 2 O 3 (phen) 3 (Hcit)] • 5.5H 2 O [6] 1.851(4) 2.082(4) [6] 1.858(1) 2.072(1) [V 2 O 3 (phen) 3 (R,S-H 2 homocit)]Cl • 6H 2 O [6] 1.858(4) 2.085(4) [13] 1.982(2) av 1.980(2) av K 2 [V 2 O 4 (gly) 2 ] [14] 1.979(3) 1.973(3) Rb 2 [V2O4(gly) 2 ] [15] 1.980( 2 VFe 7 S 8 C(CO 3 )[R-(H)homocit] 5N6Y [1a] 2.170 VFe 7 S 7 C(CO 3 )(NH/OH)[R-(H)homocit] 6FEA [1b] 2.160 VFe 7 S 7 C(CO 3 )(μCO)[R-(H)homocit] 7ADR [1c] 2.146 VFe 7 S 7 C(CO 3 )(OH)[R-(H)homocit] 7ADY [1c] 2.143 VFe 7 S 7 C(CO 3 )(μCO)(tCO)[R-(H)homocit] 7AIZ [1d] 2 and 1631 cm À 1 for 3 respectively are attributed to antisymmetric stretching vibrations ν as (CO 2 À ). The vibration observed at 1721 cm À 1 for 1 is related to the uncoordinated β-CO 2 H group.…”