TY  - JOUR
A2  - Anson, Christopher E
A2  - Creaser, Colin S
A2  - Daul, Claude A
AB  - FTIR spectra of tricarbonyl(η⁶-benzo-15-crown-5)chromium(0) (<b>1</b>) 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<sub>sym</sub>) and antisymmetric (ν<sub>asym</sub>) 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 <b>1·</b>Na⁺ and dimensions from DFT-derived structures of <b>1·</b>Li⁺, <b>1·</b>Na⁺ and <b>1·</b>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 <b>1</b>, 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<sub>sym</sub> and ν<sub>asym</sub>. A comparison of the FTIR data from <b>1</b>, tricarbonyl(η⁶-1-phenyl-1-aza-15-crown-5)chromium(0) (<b>2</b>) and tricarbonyl(η⁶-2-phenyl-15-crown-5)chromium(0) (<b>3</b>) with a wider range of cations (NH₄⁺, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ba²⁺) and anions (AcO⁻, BPh₄⁻, Br⁻, C1O₄⁻, I⁻, SCN⁻), showed that <b>1</b> and <b>3</b> both responded significantly to the different metal cations, but <b>2</b> did not. The relative cation differentiation of <b>1</b>, <b>2</b> and <b>3</b> was measured using the parameter Δ<sub>R(cation)</sub>, and ratios of Δ<sub>N(cation)</sub> values [calculated from Δ<sub>R(cation)</sub>] distinguished different effects in the FTIR spectra of <b>1</b> and <b>3</b> for different pairs of cations.
AU  - Stephenson, G. Richard
DB  - RERO DOC
DO  - 10.1002/ejic.201001274
EP  - 2097
ID  - 24999
SP  - 2097
T2  - European Journal of Inorganic Chemistry
TI  - Spectroscopic, structural and DFT study of the responses of carbonylmetal crown ether complexes to alkali metal cations
UR  - http://dx.doi.org/10.1002/ejic.201001274
UR  - http://doc.rero.ch/record/24999/files/dau_ssd.pdf
UR  - http://doc.rero.ch/record/24999/files/dau_ssd_sm.pdf
Y2  - 2021-03-05T21:06:29+01:00
ER  -