title: Cationic D4R zinc phosphate-anionic polyoxometalate hybrids: synthesis, spectra, structure and catalytic studies.
abstract: A facile synthetic strategy for the generation of a new class of inorganic-organic-inorganic hybrids is reported. Replacement of labile DMSO ligands from the preformed Double-Four-Ring (D4R) zinc phosphate cluster [Zn(dipp){(CH3)2SO}]4 by the addition of 4-aminopyridine (4-ampyr) results in the isolation of another discrete D4R cluster [Zn(dipp)(4-ampyr)]4 (1), which forms a hydrogen-bonded framework in solid-state. If 1-methyl-4,4'-bipyridinium salts are employed instead, tetra-cationic D4R cluster [Zn(dipp)(L)]4[PF6]4 (2) and [Zn(dipp)(L)]4[ClO4]4 (3) (L = 1-methyl-4,4'-bipyridinium, dipp = 2,6-di-iso-propylphenylphosphate) are isolated. Compound 2 was reacted with three different polyoxometalates, [TBA]4[Mo8O26] (POM-1), [TBA]4[PMo11VO40] (POM-2), and [TBA]4[SiMo12O40] (POM-3) to obtain amorphous hybrids, [Zn(dipp)(L)]4[Mo8O26] (4), [Zn(dipp)(L)]4[PMo11VO40] (5), and [Zn(dipp)(L)]4[SiMo12O40] (6), respectively. All the hybrid materials have been characterized by analytical and spectroscopic studies. The molecular structure of 1 has also been determined by single-crystal XRD measurements. N2 gas sorption analyses show moderate BET surface area and also establish the mesoporous nature of the hybrids 4-6. The catalytic potential of hybrids 4, 5 and 6 has been explored towards epoxidation of cyclohexene.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
authors.forename: Alok Ch
authors.initials: ACh
authors.lastname: Kalita
authors.forename: Catherine
authors.initials: C
authors.lastname: Roch-Marchal
authors.forename: Ramaswamy
authors.initials: R
authors.lastname: Murugavel
mesh_terms: D000838:Anions / Q000737:chemistry; D002384:Catalysis; D002412:Cations / Q000737:chemistry; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010316:Particle Size; D010710:Phosphates / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013499:Surface Properties; D017973:Tungsten Compounds / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D000838:Anions; D002412:Cations; D009942:Organometallic Compounds; D010710:Phosphates; D017973:Tungsten Compounds; D015032:Zinc; C102296:polyoxometalate I; D000099294:Polyoxometalates