Three new Strandberg-type phenylphosphomolybdate supports for immobilizing horseradish peroxidase and their catalytic oxidation performances

Abstract

Three organic-inorganic hybrids containing Strandberg-type phenylphosphomolybdate anion [(C6H5PO3)2Mo5O15]4- with phenylphosphonate (PhP) centers, transition metal (TM) ions and 2,2'-biimidazole (H2biim) ligand, formulated as [(TM(H2biim)2)2(C6H5PO3)2Mo5O15]·H2O (TM = Co and Cu, abbreviated as Co-(PhP)2Mo5 and Cu-(PhP)2Mo5, respectively) and ([Ni(H2biim)3])2[(C6H5PO3)2Mo5O15]·2H2O (abbreviated as Ni-(PhP)2Mo5), were self-assembled by simple hydrothermal methods and were systematically characterized through single-crystal X-ray diffraction and other physicochemical and spectroscopic methods, which demonstrated that TM-H2biim complexes were firstly introduced into Strandberg-type organophosphomolybdate skeletons. Selecting the oxidation of cyclohexanol to cyclohexanone as a model reaction, using H2O2 as an oxidant, the catalytic oxidation activities of the Strandberg-type compounds were firstly evaluated. More importantly, these TM-(PhP)2Mo5 (TM = Co, Cu, Ni) compounds were employed to immobilize horseradish peroxidase (HRP), and showed high adsorption capacities for HRP. Laser scanning confocal microscope images showed that HRP adsorbed on the surfaces of the TM-(PhP)2Mo5 supports. Application of immobilized enzyme HRP/TM-(PhP)2Mo5 for the detection of H2O2 is also discussed.

Crystal structure of tetrakis(1H-benzo[d]imidazol-3-ium) bis(μ5-phenylphosphonato)-pentakis(μ2-oxido)-decaoxo-penta-molybdenum dihydrate, C40H42Mo5N8O23P2

“…The title compound is synthesized under hydrothermal condition and its asymmetric unit contains a Strandberg-type anion, four protonated-benzimidazole counter cations and two water molecules (see the Figure). Its bond lengths and angles are in the expected ranges [8,9]. Its structure is threedimensional due to the existence of some weaker interaction such as CH…”

A Novel Tri-Coordination Zinc Complex Functionalized Silicotungstate with ROS Catalytic Ability and Anti-Tumor Cells Activity

“…Polyoxometalates (POMs), a particularly attractive family of late metal oxygen clusters, possess multiform structures and various useful properties [13][14][15][16]. POMs have several features that allow them to act as bulky polydentate ligands; for example, nanosized dimensions, an oxygen-abundant surface, nucleophilic properties, and poly-bond-making sites, which may allow them to bond with transition-metal ions in flexible coordination configurations [17][18][19][20][21][22][23][24][25]. Recent research has noted that the oxidation catalytic activity of Keggin-type POM fragments is remarkable [26,27] and that it could potentially facilitate the catalyzation of transition-metal ion-triggered production of ROS [28].…”

An efficient way for the synthesis of covalent Strandberg-type phosphomolybdate compound H6P2Mo5O23

“…In varieties of building blocks, Strandberg-type ([P 2 Mo 5 O 23 ] 6− ) fragment have several inherent advantages such as nano-size, nucleophilic oxygen-enriched surface and poly-bond-making sites, endowing it with the ability to serve as bulky polydentate ligands to incorporate in multiple metal ions with flexible coordination modes [4][5][6][7][8][9][10][11][12]. Moreover, researches have indicated recently that the POMs with Strandberg-type fragment have an excellent oxidation catalytic capacity, for example, oxidation of styrene and ketalization of cyclohexanone with glycol [13,14].…”

“…However, In contrast to the Keggin-, Dowson-and Anderson-type structures of polyoxomolybdates (POMos), the researches on Strandberg-type POMos are lagging behind [15]. Furthermore, hitherto, the synthetic methods of Strandberg-type POMos are most rely on hydrothermal synthesis method [4,5,[7][8][9][10][11][12][13][14], which provides us a good opportunity to exploit a simpler, less energy-intensive synthesis method in composing Strandberg-type structure containing compounds, especially the synthesis method of [P 2 Mo 5 O 23 ] 6− precursor.…”