Electrophilic and nucleophilic displacement reactions at the bridgehead borons of tris(pyridyl)borate scorpionate complexes

Abstract

Although a wide variety of boron-based “scorpionate” ligands have been implemented, a modular route that offers facile access to different substitution patterns at boron has yet to be developed. Here,...

Copper(I), Silver(I), and Gold(I) Ethylene Complexes of Fluorinated and Boron-Methylated Bis- and Tris(pyridyl)borate Chelators

“…Since early reports by Hodgkins in 1993 on bis­(pyridyl)­borates ( 1 ) and Jäkle in 2012 on tris­(pyridyl)­borates ( 2 ), − there has been growing interest in poly­(pyridyl)­borates, − which represent a new addition to the very popular scorpionate family. , These poly­(pyridyl)­borates have several attractive features over the better-known poly­(pyrazolyl)­borates as they have more thermally stable B–C linkages (compared to the relatively polar B–N linkages of the latter), four-substitutable positions on pyridyl groups ( vs three on pyrazolyl moieties), a closer proximity of the heterocyclic ring substituent to the metal site, and are believed to be better σ-donor ligands . Interestingly, despite several emerging applications, the reported poly­(pyridyl)­borates were limited to the parent systems based on unsubstituted pyridyl moieties ( e.g.…”

“…, [PhB­(Py) 3 ] − ) and those involving nonfluorinated substituents at the pyridyl 6-position ( e.g. , [PhB­(6-(R)­Py) 3 ] − , where R = Me, i -Pr). ,,,− ,, Previous studies involving [PhB­(3-(CF 3 )­Pz) 3 ] − and [MeB­(3-(CF 3 )­Pz) 3 ] − with Cu­(I) and Ag­(I) ethylene show that the change of substituent on boron from phenyl to methyl elicits a change in the tris­(pyrazolyl)­borate coordination from κ 2 to κ 3 mode ( e.g. , Figure , 10 and 11 ). , Thus, we are also interested in probing the effects of B-Me vs B-aryl groups in tris­(pyridyl)­borate coordination modes using ligands such as 9 and to compare the outcome to the better-known tris­(pyrazolyl)­borates.…”

Carbonyl and Isocyanide Complexes of Copper and Silver Supported by Fluorinated Poly(pyridyl)borates

“…In contrast to the pyrazole based poly­(pyrazolyl)­borates, , the pyridine based poly­(pyridyl)­borates are a recent addition to the scorpionate family. , The paucity of ligand variations apart from those based on the parent 2-pyridylborate is also noteworthy. Nevertheless, poly­(2-pyridyl)­borates are finding increasing utility as metal ion chelators, − as they bring different donor properties (pyridyl vs pyrazolyl), backbone stabilities (attributable to less polar B–C linkages vs B–N), and steric profiles (due to the involvement of six-membered pyridyl donor arms instead of the five-membered pyrazolyl moieties) relative to the pyrazolyl counterparts …”

Tris(pyridyl)borates: an emergent class of versatile and robust polydentate ligands for catalysis and materials applications

“…6 This Frontier article describes our work on Tpyb ligands and metal complexes, as well as recent efforts by other groups exploring the properties and applications of this family of ligands and their complexes. Our work to date has focused primarily on the formation of homoleptic octahedral metal complexes, their further elaboration via postfunctionalization, 19,20 supramolecular assembly, 21 as well as incorporation into polymeric materials. 22,23 Recently, heteroleptic complexes have been developed in parallel by the Comito, Dias, and Hikichi groups.…”