Template synthesis of {(Mo^V₂O₄)(O₃PCH₂PO₃)}_nclusters (n = 3, 4, 10): solid state and solution studies

Abstract

The influence of three exogenous ligands (acetate, formate and carbonate) on the condensation process of the [Mo2O4]2+ dioxocation with the [O3PCH2PO3](4-) group has been investigated. Four cyclic or bicyclic compounds have been isolated and characterized by X-ray diffraction studies. Two closely related acetato and formato ovoidal duodecanuclear compounds, Na24[Na4(H2O)6[(Mo2O4)10(O3PCH2PO3)10(CH3COO)8(H2O)4]].103H2O (1) and Na28[Na2[(Mo2O4)10(O3PCH2PO3)10(HCOO)10]].110H2O (2), respectively, have been obtained. Their structures can be described as two interconnected nonequivalent wheels, delimiting a large cavity. When the condensation is performed in similar conditions but replacing carboxylato groups by carbonato ligands, the ellipsoidal octanuclear Na11[Na(H2O)2[(Mo2O4)4(O3PCH2PO3)4(CO3)2]].70H2O (3) compound is isolated. 31P NMR spectroscopic studies have shown that complexes 1 and 3 are stable in solution at room temperature. Nevertheless, on heating an aqueous solution of 3, the Na8[(Mo2O4)3(O3PCH2PO3)3(MoO4)].18H2O (4) complex, free of carbonato groups, is obtained. 4 is a hexanuclear Mo(V) wheel encapsulating a tetrahedral [Mo(VI)O4](2-) anion. Its rational synthesis using a controlled Mo(V)/Mo(VI) ratio is also presented.

Tetra‐ to Dodecanuclear Oxomolybdate Complexes with Functionalized Bisphosphonate Ligands: Activity in Killing Tumor Cells

“…We initiated a study of the reactivity of the reduced dinuclear {Mo V 2 O 4 } 2+ group with bisphosphonates, starting with the simplest species, methylenediphosphonate (R 1 =H, R 2 =H), and reported a large family of ring‐shaped reduced POMs built up by alternating organic ligands and dimers of edge‐sharing Mo V octahedra with the general formula {(Mo V 2 O 4 )(O 3 PCH 2 PO 3 )} n ( n =3, 4, 6, 10) 14. Some of these compounds encapsulated extra ligands, such as carbonate,14a sulfite,14b or methylarsenate 14c. These anions have been successfully used as both reductants and as stabilizing agents for the synthesis of metallic nanoparticles (Pd 0 , Pt 0 , Ag 0 ),14c, 15 and we recently extended this family of compounds by using the commercial drug etidronate (R 1 =OH, R 2 =CH 3 ) 16…”

Novel Methanol‐Containing Oxomolybdate(V) Complexes: Synthesis and Structural Characterisation of Intermediates in the Formation of {Mo2O4}2+ Clusters from [MoOCl4(H2O)]– and [MoOBr4]– Precursors

“…{Mo 2 O 4 } 2+ clusters with metal d electrons localised in single metal–metal bonds occupy a prominent position among the polyoxometallates, which continue to be a subject of great interest because of their potential applications ranging from catalysis to medicine 1. Their basic building blocks, dinuclear {Mo 2 O 4 } 2+ moieties (Scheme ) with a well‐defined geometry,2,3 can assemble in many different ways and lead to a variety of metal oxide cores, as illustrated by some recently prepared clusters, i.e., [(Mo 2 O 4 ) 4 (OMe) 6 (MeOH) 4 Cl 2 ],4 bimetallic alkoxides [M 2 (Mo 2 O 4 ) 2 (O i Pr) 14 ] (M = Ta, Nb),5 [(Mo 2 O 4 ) 6 (μ 2 ‐SO 3 ) 12 (μ 3 ‐SO 3 ) 4 ] 20– ,6 [Na 4 (H 2 O) 6 {(Mo 2 O 4 ) 10 (P 2 O 7 ) 10 (CH 3 COO) 8 (H 2 O) 4 }] 24– ,7 [(Mo 2 O 4 ) 3 (O 3 PCH 2 PO 3 ) 3 (MoO 4 )] 8– ,8 [Na(H 2 O) 2 {(Mo 2 O 4 ) 4 (O 3 PCH 2 PO 3 ) 4 (CO 3 ) 2 }] 11– ,9 and a series of nano‐sized, mixed‐valence Mo V /Mo VI acetate complexes 10. Theoretical calculations have been performed on some of these species in order to understand the bonding of such complex architectures 11.…”

Syntheses and a Solid State Structure of a Dinuclear Molybdenum(V) Complex with Pyridine

“…The {Mo 2 O 4 } 2+ core (shown in Scheme 1) with d electrons localized in a Mo(V)−Mo(V) single bond appears as a recurrent structural motif in many contexts of molybdenum(V) coordination chemistry [1,2,3,4,5,6,7]. A group of high-nuclearity oxomolybdenum(V) complexes whose structures may be seen as the assemblies of two or more {Mo 2 O 4 } 2+ units has emerged in the past two decades [8].…”