ABSTRACT
The reaction of Mn(OAc)2 x 4H2O with 2,6-dimethoxybenzoylsalicylhydrazide (H3dmbshz) leads to a dodecanuclear manganese metallamacrocycle [Mn12(dmbshz)12(EtOH)6], 1. The successive manganese centers are connected by the hydrazide N-N groups of the ligands in an alternating pentadentate binding mode, hexadentate binding mode. The alternation results in two alternating chelation modes around the metal centers, a tridentate-tridentate chelation mode and a bidentate-tridentate chelation mode. The metal ions in 1 are in a (A(A)Delta(B)C(A)Lambda(B))(A(A)Delta(B)C(A)Lambda(B)) chiral sequence, the alternation of the chiralities expanding the cyclic ring system to a 36-membered dodecanuclear manganese metallamacrocyclic ring system with S6 point group symmetry.
ABSTRACT
Either an S 8 symmetrical 48-membered hexadecanuclear or an S 10 symmetrical 60-membered icosanuclear manganese metallamacrocycle was self-assembled using a manganese ion and a ditopic pentadentate ligand. This was either N-4-phenylbenzoylsalicylhydrazide (H 3pbshz) containing a rigid rod-shaped, bulky biphenyl residue as a terminal N-acyl group or N-3,3-diphenylpropionylsalicylhydrazide (H 3dppshz) containing a flexible beta-branched N-acyl group, but with two sterically bulky phenyl residues at the Cbeta position. The backbone of these metal-organic assemblies is a repeating unit consisting of a -[Mn-N-N-] link that extends to complete either the 48-membered cyclic structure involving 16 manganese(III) centers and 16 ditopic linker ligands or the 60-membered cyclic structure involving 20 manganese(III) centers and 20 ditopic linker ligands (depending on the ligand used). Even though the nuclearity of the metallamacrocycles was different, the successive manganese centers were in the same chiral sequence, ...(LambdaLambdaDeltaDelta)(LambdaLambdaDeltaDelta)....
ABSTRACT
An S6-symmetric hexanuclear gallium metalladiazamacrocycle, [Ga(III)(6)L2(6)S6] with a -(lamda delta)(lamda delta)-chiral sequence and an S-symmetric hexadecanuclear manganese metalladiazamacrocycle, [Mn(III)(16)L2(16)S16] with a -(lamda lamda delta delta)(lamda lamda delta delta)-chiral sequence were prepared using the same N2-trans-cinnamoyl-2-hydroxy-3-naphthoylhydrazide (H3L2) as a bridging pentadentate ligand between the metal centers for the formation of a macrocyclic system.
