Synthesis and Properties of N,N-diethylacetamido Derivatives of p-tert-butyl calix(n)arene

New calix[n]arene derivatives i.e. 5,11,17,23,29,35-hexa-tert-butyl-bis[(N,N-diethylaminocarbonyl)metoxy]-tetrahydroxy-calix[6]arene (3), 5,11,17,23,29,35-hexa-tert-butyl-tetrakis-[(N,N-diethylaminocarbonyl) metoxy]- dihydroxy-calix[6] arene (5), 11,17,23,29,35,41,47-tert-butyl-tetrakis-[(N,N-diethylaminocarbonyl) methoxy]-tetra-hydroxy-calix[8]arene (6) and 5,11,17,23,29,35,41,47-tert-butyl-hexakis-[(N,N-diethylaminocarbonyl)methoxy]-dihydroxy-calix[8]arene (7) have been synthetised by reaction of the parent calix[n]arene (n=6,8) with alpha-Chloro-N,N-diethylacetamide and K2CO3 or NaH as base in organic solvents such as CH3CN, THF, DMF or their mixture. The new calixarenes derivatives have been investigated by elemental analysis, H-1-NMR, UV-Vis and FTIR spectroscopy and were tested for the extraction of precious metals from aqueous solutions.