Covalent Attachment of Thiophene Groups to Polyoxomolybdates or Poly­oxotungstates for the Formation of Hybrid Films

Abstract

A novel bisphosphonate ligand bearing a thiophene group (AleThio) was synthesized and its covalent grafting to polyoxometalates (POMs) investigated. The hybrid polyoxomolybdate [(Mo3O8)4(O3PC(O)(C3H6NH2CH2C4H3S)PO3)4]8– [Mo12(AleThio)4] was synthesized in water by the reaction of Na2MoO4 with AleThio. It is built of four {MoVI3O8} units connected by phosphonate groups around a central Na+ ion. The reaction of the trivacant [PW9O34]9– units with CoII or NiII ions in the presence of AleThio led to the sandwich‐type anions [(PW9O34)2(OH)2(H2O)4M7(O3PC(O)(C3H6NH2CH2C4H3S)PO3)2]14– [M = Ni, Co; M7(AleThio)2]. Salts soluble in organic solvent were prepared by cation‐exchange with bis(triphenylphosphine)iminium ions. 31P NMR spectroscopy showed that Mo12(AleThio)4 is stable in acidic medium (pH ≤ 4) while the M7(AleThio)2 POMs are stable in alkaline medium (6 ≤ pH ≤ 13). Their cyclovoltammograms were recorded in solution. Attempts to surface immobilize the POMs through homo‐polymerization were unsuccessful but co‐polymerization employing 3‐methylthiophene led to polymeric films with covalently attached POMs.

Probing Frontier Orbital Energies of {Co9(P2W15)3} Polyoxometalate Clusters at Molecule–Metal and Molecule–Water Interfaces

“…that covalently bind, or chemisorb, to a specific surface. In recent years it was demonstrated that such groups can be introduced into POM species by attachment of various organic ligands, e.g., alkoxides, siloxanes, and organo(bis)phosphonates and -arsonates, 4 − 6 although examples of functionalized magnetic POMs are still scarce, 5 despite the prospect that POM functionalization with glue groups has already enabled well-ordered patterning of various surfaces. 6 …”

“…Until now no magnetic organoarsonate–polyoxotungstate derivatives have been reported, although several magnetic bisphosphonates-containing POMs are known, 5 e . g., [{( B -α-PW 9 O 34 )Co 3 (OH)(H 2 O) 2 (Ale) 2 } 2 Co] 14– (H 5 Ale = ( + H 3 N(CH 2 ) 3 )(OH)C(PO 3 H 2 ) 2 ), which was shown to exhibit single-molecule magnet features and is composed of two { B -α-PW 9 O 34 Co 3 } subunits connected via an additional Co II center as well as two alendronate ligands.…”

Polyoxovanadates with Ethylidene-Pyridine Functionalized Bisphosphonate Ligands: Synthesis, Structure, Spectroscopic Characterization, Magnetic, and Antibacterial Studies

“…47 Recently, polyoxotungstatebisphosphonates containing lacunary keggin-assemblies and with 3d-transition metals have also been reported. These include assemblies of {PW9O34} 9-with cobalt(II) and 1-hydroxy-4-((pyridin-2-ylmethyl)amino)butane-1,1-bisphosphonic acid, 48 4-(bis(pyrid-2-ylmethyl)amino)-1hydroxybutane-1,1-bisphosphonic acid, 48 1-hydroxy-4-((thiophen-3-ylmethyl)amino)butane-1,1bisphosphonic acid, 49 or 4-amino-1-hyrdoxy-butane-1,1-bisphosphonate; 50 of {PW9O34} 9or {SiW9O34} 10-with nickel(II) and 4-amino-1-hyrdoxy-butane-1,1-bisphosphonate [51][52] or 1-hdroxy-4-(naphthalen-1-ylmethyl)aminobutane-1,1-diphosphonic acid; 53 and of {SiW9O34} 10-, {SbW9O33} 9or {P2W15O56} 12-with copper(II) and 4-amino-1-hyrdoxy-butane-1,1bisphosphonate. 54 Mixed-metal lanthanide derivatives with {AsW9O33} 9-and containing 1hydroxyethane-1,1-bisphosphonate have been reported with Ce, Nd, Sm and Eu.…”

Assembly of a Hexameric Cluster of Polyoxomolybdotriphosphonate Builts from [Zn(H2O){TeMo6O21}{N(CH2PO3)3}]6– Subunits and Its Optical and Catalytic Properties

“…Polyoxometalates (POMs), as anionic transition-metal (e.g., Mo, W, V, Nb, Ta) oxygen-rich clusters, have been investigated not only because of their captivating structural and compositional diversity but also because of their potential applications in spectroscopy, biomedicine, magnetism, materials science, and nanotechnology. − In the last few decades, we have seen the tremendous development of POMs. − It is worth mentioning that organic–inorganic POMs, as a branch of POMs, have attracted much attention because they possess distinct structural characteristics and new properties: for example, as sorbents, ion exchangers, ionic conductors, nonlinear optical materials, sensors, catalysts, and so on. − The organic or organometallic ligands inserted into POM building blocks (such as organotin, carboxylic acid, alkoxy, organosilicon, and organophosphonate) have achieved a dominant position. − Within this field, great effort has been made and considerable attention has been given to organophosphonate-based POM derivatives, which have been developed largely by Zubieta, , Dolbecq, , Kortz, , and Mialane …”

“…18−23 The organic or organometallic ligands inserted into POM building blocks (such as organotin, carboxylic acid, alkoxy, organosilicon, and organophosphonate) have achieved a dominant position. 24−28 Within this field, great effort has been made and considerable attention has been given to organophosphonate-based POM derivatives, which have been developed largely by Zubieta, 29,30 Dolbecq,31,32 Kortz, 33,34 and Mialane. 35 To date, organophosphonate-functionalized POMs, including organophosphonate-modified polyoxotungstates (W/O/ RPO 3 2− ), organophosphonate-modified polyoxovanadates (V/ O/RPO 3 2− ), and organophosphonate-modified polyoxomolybdates (Mo/O/RPO 3 2− ), have been reported (R = CH 2 , CH 3 CH 2 , CH 2 C 6 H 4 NH 3 , HOOCC 6 H 4 , HOOCCH 2 , CH 2 CH 2 NH 3 , etc.).…”