Persistence of C–H⋯π(chelate ring) interactions in the crystal structures of Pd(S2COR)2. The utility of Pd(S2COR)2 as precursors for palladium sulphide materials
The crystallographic structures of 12 palladium xanthates, PdIJS2COR)2 (R = alkyl) show a uniform adoption of square-planar PdS4 geometries. Supramolecular aggregation in 1 (R = Me), 2 (Et) and 3 (n-Pr) is based on secondary Pd⋯S interactions, which are “turned off” when the bulk of R increases. In...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Published: |
Royal Society of Chemistry
2016
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| Subjects: | |
| Online Access: | http://eprints.sunway.edu.my/615/ http://dx.doi.org/10.1039/c5ce02126j |
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| Summary: | The crystallographic structures of 12 palladium xanthates, PdIJS2COR)2 (R = alkyl) show a uniform adoption
of square-planar PdS4 geometries. Supramolecular aggregation in 1 (R = Me), 2 (Et) and 3 (n-Pr) is based
on secondary Pd⋯S interactions, which are “turned off” when the bulk of R increases. In 4 (i-Pr), C–H⋯S
hydrogen bonding is present. In each of 2–4, C–H⋯π(PdS2C) interactions are incorporated within the architecture,
stabilised by Pd⋯S secondary- or C–H⋯S hydrogen-bonding. In 5–12 (R = n-Bu, i-Bu, n-Pent, i-
Pent, neoPent, n-Hex, i-Hex, neoHex), varying numbers of stand-alone C–H⋯π(PdS2C) interactions involving
different hydrogen donors uniformly stabilise supramolecular chains in their crystal structures. In order
to determine the relative importance of the various intermolecular interactions and packing effects, a computational
study using dispersion-corrected density-functional theory was performed on 3 (R = n-Pr). The
results showed that the most significant contributors to the stability of the crystal structure are Pd⋯S interactions
followed closely by C–H⋯π(PdS2C) interactions. Two non-specific hydrophobic interactions also
contribute to the overall packing to a lesser extent. The utility of PdIJS2COR)2 to function as synthetic precursors
for PdS nanoparticles and thin films was also investigated. Aerosol-assisted-CVD on representative
examples generated PdS films with either matted, needle-like or granular morphologies depending on
temperature and substrate. Solvothermal (ethylene glycol) decomposition generated sulphur-rich PdS
nanoparticles with diameters 120 nm (7 and 10)–400 nm (8). When dodecanethiol was employed as a capping
agent, PdS1.75 nanoparticles <10 nm were generated from 1. |
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