Inter- and intra-molecular pathways in polyamine synthesis from diamines †

Stereochemistry in Functionalized Macrocycle Complexes: Control of Hydroxyl Substituent Orientation

“…This is not necessarily disadvantageous, since it may well lead to enhanced subtlety in the range of ligand applications, but it is necessary then to fully characterize the stereochemistry of the complex ion systems that can be obtained. In seeking to explore the use of a simple hydroxyl group attached to the “exterior” of a macrocyclic complex as a useful form of functionalization, we have used a familiar template reaction ,,− to prepare the ligand 1 (Chart ), reduced the ligand to its amine form 2 , and prepared Co(III) complexes of this ligand. We report herein a detailed analysis of the stereochemistry of this system based upon the determination of the crystal structures of the various complexes involved.…”

Pendent Arm Formation and Extension accompanying Macrocycle Synthesis − A New Class of Ryongamines?

“…Further, a reaction well-known with other metal ion complexes of amines but rarely observed with Cu II [10] has led to the partial oxidation of the macrocyclic ring, converting one amine donor to an imine. As seen in many related instances, [11] the crystal structure of the complex shows the nitro and methyl substituents on the macrocyclic ring to adopt axial and equatorial orientations, respectively, on the chair six-membered ring formed by the macrocyclisation process. Despite this aspect of stereospecificity, there is disorder associated with the chiral centre generated on the pendent arm, indicating a complete lack of diastereoselectivity in the crystallisation process.…”

Weak Forces in Inorganic Lattices: Anion Roles in Lattice Assembly

“…10, 18 Dipicolinate, in its various protonated forms, is well known to adopt a range of coordinated forms 19 and unidentate binding through carboxylate-O is not unusual. The Cu-O bond length of 2.391(2) Å is relatively short for an axial ligand of a tetragonally elongated Cu(II) complex 20 and thus is suggestive of a moderately strong coordination interaction.…”