- A 13C and 15N Solid-State NMR Study of Structural Disorder and Aurophilic Bonding in AuI and AuIII Cyanide Complexes
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Solid-state nuclear magnetic resonance has been used to study several cyanoaurates. Carbon-13 and nitrogen-15 NMR spectra of samples enriched with isotopically labeled 13C, 15N cyanide ligands were recorded for stationary samples and
- Harris, Kristopher J.,Wasylishen, Roderick E.
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- Structure and multinuclear solid-state NMR of a highly birefringent lead-gold cyanide coordination polymer
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The coordination polymer Pb(H20)[Au(CN)2]a (1) was synthesized by the reaction of KAu(CN)2 and Pb(NO3) 2. The structure contains 1-D chains of lead(II)-OH2 linked via Au(CN)2- moieties, generating a 2-D slab; weak aurophilic interactions of 3.506(2) and 3.4885(5) A occur within and between slabs. The geometry about each lead(II) is bicapped trigonal prismatic, having six N-bound cyanides at the prism vertices and waters at two of the faces. Dehydration at 175 °C yields microcrystalline Pb[Au(CN) 2]2 (2), which, along with 1, was examined by 13C, 15N, 1H, and 207Pb solid-state NMR methods. TwO 15N resonances are assigned to the μ2-bridging and hydrogen-bonding cyanides in 1. Upon dehydration, the 207Pb NMR spectrum becomes axially symmetric and yields a reduced shielding span, indicating higher site symmetry, while the 13C and 15N spectra reveal a single cyanide. Although no single-crystal X-ray structure of 2 could be obtained, a structure is proposed on the basis of the NMR and X-ray powder data, consisting of a lead(II) center in a distorted square-prismatic environment, with cyanides present at each corner. The birefringence of single crystals of 1 is found to be 7.0 × 10-2 at room temperature. This value is large compared to that of most optical materials and can be attributed to the anisotropy of the 2-D slabs of 1, with all C≡N bonds aligned in the same direction by the polarizable lead(II) center.
- Katz, Michael J.,Aguiar, Pedro M.,Batchelor, Raymond J.,Bokov, Alexei A.,Ye, Zuo-Guang,Kroeker, Scott,Leznoff, Daniel B.
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