Molar-Ratio-Dependent Coordination Assembly of Organoiridium(III)-Octatungstate Complexes in Aqueous Solution

Sugiarto

Shinogi Jun

Sadakane Masahiro

Inorganic Chemistry

We scrutinized the speciation of Cp*Ir-containing tungsten oxide clusters (Cp* is pentamethylcyclopentadienyl anion) in aqueous mixtures of [(Cp*IrCl)2(μ-Cl)2] and Na2WO4 in varying molar ratios. 1H nuclear magnetic resonance (NMR) spectroscopy revealed the formation of three distinct Cp*Ir–polyoxotungstate species in the reaction solution, and they were isolated as Na4[(Cp*Ir)2(μ-OH)3]2[(Cp*Ir)2H2W8O30] (1), [(Cp*Ir)2(μ-OH)3]2[(Cp*Ir)2{Cp*Ir(OH2)}2H2W8O30] (2), and [(Cp*Ir)2{Cp*Ir(OH2)}2{Cp*Ir(OH2)2}2H2W8O30](NO3)2 (3) from the mixtures in which iridium concentration is less than, equal to, and more than the tungsten concentration, respectively. These results show the octatungstate [H2W8O30]10– anion is the major polyoxotungstate species in the presence of {Cp*Ir}2+ cations, and it has high nucleophilicity enough to bind up to six {Cp*Ir}2+ cations on its surfaces producing a cationic Cp*Ir–octatungstate complex. The octatungstate anion was also generated from the reaction of [(Cp*IrCl)2(μ-Cl)2] and methylammonium paratungstate-B, (CH3NH3)10[H2W12O42], and was isolated as a methylamine-coordinated complex (CH3NH3)2[(Cp*Ir)2{Cp*Ir(NH2CH3)}2H2W8O30] (4), indicating {Cp*Ir}2+ cations function as a structure-directing agent that converts tungsten species into octatungstate anions in aqueous solution. In addition, the coordination environment of {Cp*Ir}2+ can be further modified by coordination with pyridine forming [{Cp*Ir(NC5H5)}2(μ-OH)2][(Cp*Ir)2{Cp*Ir(NC5H5)}2H2W8O30] (5).

Anions

Cations

Crystals

Mixtures

Transition metals

eng

ACS Publications

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.inorgchem.3c00479

This is not the published version. Please cite only the published version.

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[DOI] https://doi.org/10.1021/acs.inorgchem.3c00479 isVersionOf

日本学術振興会

Japan Society for the Promotion of Science

[Crossref Funder] https://doi.org/10.13039/501100001691

超セラミックスの次元・形態制御

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22H05144