known to have a coordination number of seven. Nearly all of them have the basic formulation [Ln(bidentate)3(unidentate)]. On the contrary, structurally characterized examples of a heptadentate ligand coordinating one metal ion are rare. Tris(2-aminoethyl)amine (tren) condenses with salicylaldehyde or its substituted analogs in a 1:3 molar ratio to form Schiff-bases which are potentially tribasi...

part from their potential applications as magnetic and/or optical probes. There is now a substantial number of lanthanide complexes known to have a coordination number of seven. Nearly all of them have the basic formulation [Ln(bidentate)3(unidentate)]. On the contrary, structurally characterized examples of a heptadentate ligand coordinating one metal ion are rare. Tris(2-aminoethyl)amine (tre...

This paper presents a 1,4,7,10-teraazacyclododecane-based tetrakis-phenol as a protonated ligand precursor and its oxygen-sensitive luminescent terbium(III) complex with an extendable phenol pendant arm (Φ = 0.91 under N2, Φ = 0.031 under air), in which the potentially N4O4-octadentate ligand unprecedentedly coordinates to the Tb(3+) ion in a N4O3-heptadentate fashion.

A highly enantioselective method for the catalytic Mukaiyama aldol reaction of silyl enol ethers with aldehydes in aqueous conditions was developed. The desired aldol products were obtained in excellent yields, diastereo- and enantioselectivities. Structural evidence of the pre-catalyst revealed an unprecedented heptadentate Fe(II) complex with the chiral bipyridine ligand.

A highly enantioselective method for the catalytic opening of aromatic meso-epoxides with aniline derivatives was developed. The desired chiral β-amino alcohols were obtained in mostly good to very good yields with excellent enantioselectivities. Structural evidence of the pre-catalyst revealed a scarcely disclosed heptadentate Fe(II) complex with the chiral bipyridine ligand.

The heptadentate Schiff base ligand, 2-(2-hydroxyphenyl)-1,3-bis[4-(2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazoline (H(3)api), yields [Ln(2)api(2)] species when combined with lanthanide salts under basic conditions. A survey of the magnetic properties of this dinuclear lanthanide motif (Ln = Gd, Tb, Dy, Ho) has identified weak magnetic exchange, antiferromagnetic in nature for the isotropic g...

Two potentially heptadentate (N4O3) tripodal Schiff-base ligands: tris(3(salicylideneimino)propyl)amine (H3L1) and tris(3-(4'-hydroxysalicylideneimino)propyl)amine (H3L2) have been prepared and characterized by various spectroscopic methods (IR, FAB-MS, NMR). They are derived from the condensation reactions of tris(3-aminopropyl)amine (tpt), with 3 equivalents of either salicylaldehyde or the r...

Complexes of Gd, Eu and Yb(III) have been prepared with a series of heptadentate ligands related to the parent complex AAZTA, based on the 6-methyl-6-aminoperhydrodiazepine moiety. For (RR) and (RS)-diastereoisomers of a di-glutarate ligand, solution NMR studies revealed the presence of two major species that undergo water exchange rates at Gd differing by a factor of six. Comparison of solutio...