Heterobimetallic Complexes of Polypyridyl Ligands Containing Paramagnetic Centers: Synthesis and Characterization by IR and EPR

Abstract

Ligands containing linked dipicolylamine (dpa) and bipyridine sites have been explored as platforms for the synthesis of heterometallic complexes containing the paramagnetic metals Cu(2+) and Co(2+). IR and EPR studies on the bimetallic complexes and simplified model compounds support dpa-selective binding by both of these metals. The IR spectra have also been compared to those of diamagnetic Rh(+), Zn(2+), and Pd(2+) complexes whose metal binding sites had been independently determined through NMR techniques. The binding preferences have been used to control selective metalation in the synthesis of heterometallic Pt/Cu, Pd/Cu, and Rh/Cu complexes.

Construction of Coordination Nanosheets Based on Tris(2,2′-bipyridine)–Iron (Fe2+) Complexes as Potential Electrochromic Materials

“…The FTIR spectra indicated characteristic CC stretching frequencies of BP1 and BP2 at 1590 and 1588 cm –1 , respectively, which were shifted to a higher wavelength of 1612 cm –1 for NBP1 and 1606 cm –1 for NBP2 (Figure S5a). These observations are consistent with those for other reported polypyridyl metal complexes. , Additionally, a broad peak at around 1056 cm –1 , which can be assigned for a BF – anion, was observed in both the CONASHs. The IR spectra of the reference MC revealed the presence of 1606 and 1056 cm –1 for CC and BF – anion, confirming the complete formation of a coordination complex in the CONASHs.…”

“…These observations are consistent with those for other reported polypyridyl metal complexes. 23,61 Additionally, a broad peak at around 1056 cm −1 , which can be assigned for a BF − anion, was observed in both the CONASHs. The IR spectra of the reference MC revealed the presence of 1606 and 1056 cm −1 for CC and BF − anion, confirming the complete formation of a coordination complex in the CONASHs.…”

Precise Synthesis of Alternate Fe(II)/Os(II)‐Based Bimetallic Metallo‐Supramolecular Polymer

“…The reason for the lower frequencies of C=C stretching in OsL1 is due to the presence of the free terpyridine moieties which show higher frequencies shifting upon complexation with metal ion. [9] The thermal stability of polyFeOs was measured by thermogravimetric analysis (TGA) under an N 2 atmosphere. The TGA analysis shows two degradation points.…”

Mechanism of Evolution of Koneramine Complexes from One‐Pot Reactions: Snapshots of Intermediates Offer Facile Routes to New Dipicolylamines

“…[8][9][10][11] Anslyn and co-workers employed dpa-based compoundsi nd ynamic multicompo-nent covalenta ssemblies that are useful as chirality sensing agents. [12][13][14][15][16][17] Transition-metal complexeso fd pa-based ligands [18][19][20][21] are further seen in the literature frequently as new peptides, [22,23] artificial enzymes, [24] catalysts, [25][26][27][28][29] etc.T he strong chelating ability of tridentate dipicolylamine is often compromised as the centralNdonor (NH) of dpa is used as the substitution point for different functional componentst o create new ligands, thereby weakening the basicity of the N2 donor at times. The koneramines reported here have the fourth nitrogena tom that is not participating in coordination but available for any functional groups, which could make the koneramine complexes better than dipicolylamine complexes.…”

“…Anslyn and co‐workers employed dpa‐based compounds in dynamic multicomponent covalent assemblies that are useful as chirality sensing agents . Transition‐metal complexes of dpa‐based ligands are further seen in the literature frequently as new peptides, artificial enzymes, catalysts, etc. The strong chelating ability of tridentate dipicolylamine is often compromised as the central N donor (NH) of dpa is used as the substitution point for different functional components to create new ligands, thereby weakening the basicity of the N2 donor at times.…”