1185907-08-7Relevant articles and documents
Interplay between the Conformational Flexibility and Photoluminescent Properties of Mononuclear Pyridinophanecopper(I) Complexes
Patil, Pradnya H.,Filonenko, Georgy A.,Lapointe, Sébastien,Fayzullin, Robert R.,Khusnutdinova, Julia R.
supporting information, p. 10009 - 10027 (2018/08/28)
The macrocyclic ligand conformational behavior in solution, solid-state structures and the photophysical properties of copper(I) cationic and neutral mononuclear complexes supported by tetradentate N,N′-dialkyl-2,11-diaza[3.3](2,6)-pyridinophane ligands RN4 (R = H, Me, iBu, secBu, neoPent, iPr, Ts) were investigated in detail. Steric properties of the alkyl group at the axial amine in the RN4 ligand were found to strongly affect the conformational preferences and dynamic behavior in solution. Several types of conformational exchange processes were revealed by variable-temperature NMR and 2D exchange spectroscopy, including degenerative exchange in a pseudotetrahedral species as well as exchange between two isomers with different conformers of tri- and tetracoordinate RN4 ligands. These exchange processes are slower for the complexes containing bulky alkyl groups at the amine compared to less sterically demanding analogues. A clear correlation is also observed between the steric bulk of the alkyl substituents and the photoluminescent properties of the derived complexes, with less dynamic complexes bearing bulkier alkyl substituents exhibiting higher absolute photoluminescence quantum yield (PLQY) in solution and the solid state: PLQY in solution increases in the order Me neoPent iBu secBu ? iPr tBu. The electrochemical properties of the cationic complexes [(RN4)CuI(MeCN)]X (X = BF4, PF6) were also dependent on the steric properties of the amine substituent.
Implications of stoichiometry-controlled structural changeover between heteroleptic trigonal [Cu(phenAr2)(py)]+ and tetragonal [Cu(phenAr2)(py)2]+ motifs for solution and solid-state supramolecular self-assembly
Neogi, Subhadip,Schmittel, Michael,Schnakenburg, Gregor,Lorenz, Yvonne,Engeser, Marianne
, p. 10832 - 10841,10 (2020/09/02)
A stoichiometric variant of the HETPYP concept (HETeroleptic PYridine and Phenanthroline metal complexes) opens the venue to heteroleptic metallosupramolecular HETPYP-I assemblies both in solution and the solid state, involving the trigonal [Cu(phenAr2)(py)]+ coordination motif (phenAr2 = 2,9-diarylphenanthroline; py = various oligopyridines). Combining the same building blocks at another stoichiometric ratio furnished metallosupramolecular HETPYP-II aggregates in the solid state, now based on the tetrahedral [Cu(phenAr2)(py)2] + coordination motif. Thus, a stoichiometry-controlled structural changeover based on the relative amounts of oligopyridines leads from a discrete assembly with trigonally coordinated copper(I) centers to a coordination polymer with tetrahedrally coordinated copper(I) ions, as shown by solid state studies. In solution, the analysis of both stoichiometric variants indicates that the HETPYP-I structure is congruent with that in the solid state, while the HETPYP-II assembly, as established through DOSY NMR and dynamic light scattering measurements, is only oligomeric at low temperature. At room temperature, i.e. due to entropic costs, the latter assembly prefers to keep unsaturated coordination sites that are in rapid exchange, making it an interesting system as a dynamic protecting group and for constitutional dynamic materials through the exchange and reshuffling of components.
