The acid dissociation constants of the hydroxyl groups in 25, 26, 27, 28-tetrahydroxy-5, 11, 17, 23-tetrasulphonic-calix[4]arene (SC4) were determined at 25οC by a combination of potentiometric and spectrophotometric titration method. The first and second acid dissociation constants (pKa1, pKa2) were found to be 3.19 and 12.1, which demonstrated pKa shift due to intramolecular hydrogen bonding ...

We consider a real analytic diffeomorphism ψ0 on a n-dimensional disk D, n ≥ 2, exhibiting a Feigenbaum-Coullet-Trésser (F.C.T.) attractor, being far, in the Cω(D) topology, from the standard F.C.T. map φ0 fixed by the double renormalization. We prove that ψ0 persists along a codimension-one manifold M ⊂ Cω(D), and that it is the bifurcating map along any one-parameter family in Cω(D) transvers...