Cupric Siliconiobate. Synthesis and Solid-State Studies of a Pseudosandwich-Type Heteropolyanion
- SBU
The Na{sup +} and [Cu(en){sub 2}(H{sub 2}O){sub 2}]{sup 2+} (en = ethylenediamine) salt of a pseudosandwich-type heteropolyniobate forms upon prolonged heating of Cu(NO{sub 3}){sub 2} and hydrated Na{sub 14}[(SiOH){sub 2}Si{sub 2}Nb{sub 16}O{sub 54}] in a mixed water-en solution. The structure [a = 14.992(2) {angstrom}, b = 25.426(4) {angstrom}, c = 30.046(4) {angstrom}, orthorhombic, Pnn2, R1 = 6.04%, based on 25869 unique reflections] consists of two [Na(SiOH){sub 2}Si{sub 2}Nb{sub 16}O{sub 54}]{sup 13-} units linked by six sodium cations, and this sandwich is charge-balanced by five [Cu(en){sub 2}(H{sub 2}O){sub 2}]{sup 2+} complexes, seven protons, and three additional sodium atoms (all per a sandwich-type cluster). Diffuse-reflectance UV-vis indicates that there is a {lambda}{sub max} at 383 nm for the Cu{sup II} d-d transition and the {sup 29}Si MAS NMR spectrum has two peaks at -78.2 ppm (151 Hz) and -75.5 ppm (257 Hz) for the two pairs of symmetry-equivalent internal [SiO{sub 4}]{sup 4-} and external [SiO{sub 3}(OH)]{sup 3-} tetrahedra, respectively. Unlike tungsten-based sandwich-type complexes, the [Na(SiOH){sub 2}Si{sub 2}Nb{sub 16}O{sub 54}]{sup 13-} units are linked exclusively by Na{sup +} instead of one or more d-electron metals.
- Research Organization:
- Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1006842
- Journal Information:
- Inorg. Chem., Journal Name: Inorg. Chem. Journal Issue: (17) ; 2008 Vol. 47; ISSN 0020-1669; ISSN INOCAJ
- Country of Publication:
- United States
- Language:
- ENGLISH
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