<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>Stephenson, G. Richard</dc:creator>
  <dc:creator>Anson, Christopher E.</dc:creator>
  <dc:creator>Creaser, Colin S.</dc:creator>
  <dc:creator>Daul, Claude</dc:creator>
  <dc:date>2011-04-20</dc:date>
  <dc:description xmlns:ns0="xml" ns0:lang="en">FTIR spectra of tricarbonyl(η⁶-benzo-15-crown-5)chromium(0) (&lt;b&gt;1&lt;/b&gt;) in the presence of lithium, sodium and potassium perchlorate salts in methanol show different responses in the Cr–CO vibrational region of the spectrum. Data from the symmetric (ν&lt;sub&gt;sym&lt;/sub&gt;) and antisymmetric (ν&lt;sub&gt;asym&lt;/sub&gt;) Cr–CO vibrational stretching modes have been analysed by principal component analysis (PCA) to generate a factor score plot that provides a visual representation of these differential responses. X-ray crystallographic data for the sodium perchlorate complex &lt;b&gt;1·&lt;/b&gt;Na⁺ and dimensions from DFT-derived structures of &lt;b&gt;1·&lt;/b&gt;Li⁺, &lt;b&gt;1·&lt;/b&gt;Na⁺ and &lt;b&gt;1·&lt;/b&gt;K⁺ indicate that binding M⁺ in the crown causes electron density and structural changes in the [O(4)–C(9)–C(4)–O(8)]Cr–C(1)=O(1) sections of &lt;b&gt;1&lt;/b&gt;, which vary depending on the nature of the cation. This suggests a mode of action in which Li⁺ associates with a more compact O(4)–C(9)–C(4)–O(8), while Na⁺ and K⁺ differ crucially in the extent of σ and π contributions to their effect on ν&lt;sub&gt;sym&lt;/sub&gt; and ν&lt;sub&gt;asym&lt;/sub&gt;. A comparison of the FTIR data from &lt;b&gt;1&lt;/b&gt;, tricarbonyl(η⁶-1-phenyl-1-aza-15-crown-5)chromium(0) (&lt;b&gt;2&lt;/b&gt;) and tricarbonyl(η⁶-2-phenyl-15-crown-5)chromium(0) (&lt;b&gt;3&lt;/b&gt;) with a wider range of cations (NH₄⁺, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ba²⁺) and anions (AcO⁻, BPh₄⁻, Br⁻, C1O₄⁻, I⁻, SCN⁻), showed that &lt;b&gt;1&lt;/b&gt; and &lt;b&gt;3&lt;/b&gt; both responded significantly to the different metal cations, but &lt;b&gt;2&lt;/b&gt; did not. The relative cation differentiation of &lt;b&gt;1&lt;/b&gt;, &lt;b&gt;2&lt;/b&gt; and &lt;b&gt;3&lt;/b&gt; was measured using the parameter Δ&lt;sub&gt;R(cation)&lt;/sub&gt;, and ratios of Δ&lt;sub&gt;N(cation)&lt;/sub&gt; values [calculated from Δ&lt;sub&gt;R(cation)&lt;/sub&gt;] distinguished different effects in the FTIR spectra of &lt;b&gt;1&lt;/b&gt; and &lt;b&gt;3&lt;/b&gt; for different pairs of cations.</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>https://folia.unifr.ch/global/documents/302023</dc:identifier>
  <dc:identifier>https://folia.unifr.ch/documents/302023/files/dau_ssd.pdf</dc:identifier>
  <dc:identifier>https://folia.unifr.ch/documents/302023/files/dau_ssd_sm.pdf</dc:identifier>
  <dc:language>eng</dc:language>
  <dc:relation>info:eu-repo/semantics/altIdentifier/doi/10.1002/ejic.201001274</dc:relation>
  <dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
  <dc:rights>License undefined</dc:rights>
  <dc:source>European Journal of Inorganic Chemistry. - 2011, p. 2086–2097</dc:source>
  <dc:subject>info:eu-repo/classification/udc/54</dc:subject>
  <dc:title xmlns:ns1="xml" ns1:lang="en">Spectroscopic, structural and DFT study of the responses of carbonylmetal crown ether complexes to alkali metal cations</dc:title>
  <dc:type>http://purl.org/coar/resource_type/c_6501</dc:type>
</oai_dc:dc>