The 1:1 arene-tricarbonylchromium complexes were synthesized for the first time from four conformational isomers of 25,26,27,28-tetrapropoxycalixarene (14Pr) and Cr(CO)6. The 1:2, 1:3 and 1:4 complexes of cone-14Pr were also synthesized by increasing the ratio of Cr(CO)6 against cone-14Pr. The 1:2 complex was a mixture of two compounds, which were identified as distal and proximal isomers of cone-14Pr·2Cr(CO)3. The relative stability of the 1:1 complex was estimated via its oxidation by CuCl2. The pseudo-first-order rate constants appeared to be in the order of 1,3-alternate-14Pr > 1,2-alternate-14Pr > cone-14Pr > 2,6-dimethylanisole. The results indicate that the 14Pr·Cr(CO)3 complexes are less stable than the corresponding monomeric complex. The 1:1 complexes with partial-cone-1 4Pr and 1,2-alternate-14Pr were demonstrated to be a pair of racemates by 1H NMR spectroscopy using a chiral shift reagent (Pirkle's reagent).
|Number of pages||6|
|Journal||Journal of the Chemical Society, Perkin Transactions 1|
|Publication status||Published - Dec 1 1993|
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