A slow rotation around C-N bonds of the naturally occurring trishydroxamic acid desferrioxamine B was investigated by H-1 and C-13 dynamic NMR techniques. Corresponding rate constants for the C-terminal, middle and N-terminal hydroxamates are 12 s(-1), 15 s(-1), and 9 s(-1), respectively. The slow rotation around the C-N bond of the middle hydroxamato group is proposed to be the rate determining step in dechelation of the middle hydroxamato group in ferrioxamine B. [GRAPHICS] study. The present paper reports a methylation process which deals with a MeOC-Rhm(III)... Pd ... Rh-III-COMe system. [GRAPHICS] t> Rh-III-COMe system. [GRAPHICS] ation of a dimeric entity is achieved by a bridging ClO4 while hydrogen bonds from the imino groups to terminal and bridging ClO4 link two dimers to yield a "dimer of dimers". [GRAPHICS] GRAPHICS]u抵