Studies on properties of tetra-p-nitro-tetra-O-alkyl-calix[4]arenes

This paper reports the properties of the novel tetra-p-nitro-tetra-O-alkyl-calix[4]arenes (alkyl = n-C4H9, 1; n-C8H17 2; n-C12H25, 3; n-C16H33, 4), X-ray crystallographic analysis and H-1 NMR revealed that they exist as pinched cone conformation in crystal or cone conformation in solution. EFISH experiments at 1064 nm in CHCl3 indicated that tetra-p-nitro-tetra-O-butyl-calix[4]arene (1) has higher hyperpolarizability beta (z) values than the corresponding reference compound p-nitro-phenyl butyl ether, without red shift of the charge transfer band. Compounds 2, 3 and 4 with longer alkyl chains can form monolayer at the air/water.