Pulled Molecular Strings and Stacked Molecular Decks: Chelate‐Ring Formation vs. Metal–Metal Bridging in Dicopper(I) Complexes of 2,2′‐Bipyrimidine with Diphosphine Ligands of Variable Polymethylene Chain Length

Abstract

Abstract:The "self-assembly" reaction troscopic results for the dissolved species polymethylene chain length 1s reduced between bischelating 2,T-bipynmidine, indicate a strained configuration in the one notch further to n = 5 (5), the diphosmetallic copper, Cu2+, and two equiva-case of complex [(p-bpym)Cu,{p-Ph,Pphines can no longer bridge but help to lents of bidentate Ph,P(CH,),PPh, pro-(CH,),PPh,),J2+ (6) with n = 6 Once the form eight-membered chelate rings (strucduces crystallographically characterized ture I). In this complex there is a distordinuclear complexes with a [Cu'(p-bpym)-tion towards a trigonal-pyramidal coordi-CU']~+ core and chelating (n = 5; type I) nation geometry at the copper(]) centers, or bridging diphosphine ligands (n = 6 , s ; which is supported by the formation of type II). Structures I1 may be designated an "organic sandwich" arrangement beas "inverse cryptate" arrangements. The tween the central bpym acceptor and two structural data of the solids and the specphosphino phenyl rings.

Side‐chain functionalized polymers containing bipyridine coordination sites: Polymerization and metal‐coordination studies

“…Herein we demonstrate the first synthesis of 2,2′‐bipyridine (bpy)‐containing monomers for ring‐opening metathesis polymerization (ROMP), the coordination of ruthenium or palladium by the pendant bpy, the subsequent functionalization of the metal center with multidentate ligands, and finally the ROMP of these monomers in nonpolar solutions with ruthenium‐based initiators. Multidentate nitrogen‐donor ligands are advantageous ligands because they are often neutral and stable in solution and form highly stable complexes with numerous transition metals 1–16. The resulting multidentate nitrogen‐donor ligand‐based metal complexes have a large number of potential applications.…”

Hybrid α‐Diimine/Bis(chalcogenoether) Ligands for Copper(I) and Copper(II) Complexes

“…Reacting 1 with the copper(I) precursor [Cu(NCCH 3 ) 4 ](BF 4 ) in 1:1 or 2:1 ratio gave a complex with the composition [Cu( 1 ) 2 ](BF 4 ) = ( 4 )(BF 4 ) (Scheme ). The crystal structure analysis revealed that this compound shows no chalcogen coordination but adopts the familiar bis(α‐diimine)copper(I) structure with a chelate‐distorted tetrahedral coordination at the metal (Figure , Table and Table S3, Supporting Information). Compound 1 thus acts only as a bidentate chelate ligand towards Cu I due to the weakness of Cu I –O bonds, especially with uncharged central oxygen atoms.…”

“…An important area of research using copper complexes of α‐diimines involves their photochemical activity and their suitability to act in topologically non‐trivial molecules,, culminating in the recognition, analysis and the specific development of molecular machines …”

Multistep redox sequences of azopyridyl (L) bridged reaction centres in stable radical complex ions {(μ-L)[MCl(η5-C5Me5)]2}˙+, M = Rh or Ir: spectroelectrochemistry and high-frequency EPR spectroscopy

“…23 The complex dications of {(µ-L)[IrCl(C 5 Me 5 )] 2 } 2ϩ were isolated in only one configuration according to the 1 H-NMR spectra; by analogy and considering the typically smaller metal-metal distances d < 5.1 Å in abpy-bridged dimers 12,14 relative to bpym-bridged dinuclear species (ca. 5.6 Å) 24 we assume these to be the anti isomers (Fig. 2).…”