Chair−Boat Form Transformation of Piperazine-Containing Ligand toward the Preparation of Dirhenium Metallacycles

Abstract

A new generation of a flexible bipyridine-based ligand, 1,4-bis(4-pyridyl)-piperazine, with two main stable states (chair and twist-boat forms) was employed in the construction of unusual dirhenium metallacycles.

Neutral discrete metal–organic cyclic architectures: Opportunities for structural features and properties in confined spaces

“…The versatility of dithiocarbamates lies in their ability to coordinate metal ions in different modes to afford discrete architectures [284]. The reaction of PtCl 2 with pyrrolidinedithioester (L143, PyDTM) afforded monometallic complex, [PtCl 2 (L143)], followed by the thermal degradation at 220 • C generated [PtCl(PyDT)] 5 (179) (Scheme 69) with two possible enantiomers ( , , , , and , , , , ) based on chiral S-bridged Pt II monomers [285].…”

“…By making use of 1,4-bis(4-pyridyl)piperazine (L53, bpp) as a flexible ligand with a restricted number of conformations, the construction of unusual metallacycles is limited (Scheme 23) [179]. Treatment of Re 2 (CO) 10 a boat or a twist-boat conformation.…”

“…(b) Chair-boat form transformation of the L53 ligand [179].Scheme 24. Synthesis of dirhenium metallacycles 75 and 76[179].…”

Self‐Assembly of Oxamidato‐Chelated ReI‐ and MnI‐Based Flexible Dinuclear Horse‐Stirrup‐Like Metallacycles

“…[10][11][12][13][14] Nevertheless, flexible tectons hold much promise, as they impart unique properties such as adaptive behavior and breathing ability on the final assemblies. [15][16][17][18][19] Hence, motivation has been provided for the exploitation of flexible linkers in the self-assembly process to render diverse metallacycles. In this context, flexible bidentate 4,4Ј-bipyridyl spacers have received great attention as multifunctional bridging ligands.…”

“…[15,[27][28][29][30][31] For the construction of such dirhenium metallacycles, bis(chelating) organic clips are usually utilized in combination with flexible dipyridyl linkers. [27,30] Owing to their efficacy in different fields such as luminescent sensors, imaging, and photocatalytic CO 2 reduction, Re I -based complexes continue to attract considerable interest for various modern applications.…”