Relationship between Metallophilic Interactions and Luminescent Properties in Pt(II) Complexes: TD-DFT Guide for the Molecular Design of Light-Responsive Materials

Abstract

DFT/TD-DFT investigation has been performed on pyridyl triazolatoplatinum­(II) complexes with a systematic variation of the donor/acceptor properties of the ligand in order to illuminate its effect on the metallophilic intermolecular interaction in ground and excited states. The π-electronic properties of the pyridyl triazolate ligand were modified by the pyridine substituent: −N­(CH3)2, −H, −CHO, or −CHC­(CN)2. The simulations reveal that the donor/acceptor strength of the substituent has a strong impact on the metallophilic interaction in the excited state and affects the emission properties at the supramolecular level. The theoretically derived structure–property relationships are corroborated by experimental data. Finally, it is proposed that the modification of the π-electronic character of the substituent (ligand field) can be applied in the molecular design of smart luminescent materials with light-driven metallophilic interactions.

Luminescent Pt(ii) complexes featuring imidazolylidene–pyridylidene and dianionic bipyrazolate: from fundamentals to OLED fabrications

“…Electronic structure calculations and TD-DFT predictions on these dimers gave similar data as for the monomer 8 as expected from a recent study on monomers and dimers of platinum(II) complexes. 25 The data here thus do not explain the observed low energy emissions for 2-7. Different computation results have been reported from monomer and dimers for a platinum complex elsewhere but a pure DFT functional (PBE0) was used for TD-DFT on dimer geometries that were optimized at the hybrid DFT functional (B3LYP).…”

Shape-Controlled Synthesis of Luminescent Hemoglobin Capped Hollow Porous Platinum Nanoclusters and their Application to Catalytic Oxygen Reduction and Cancer Imaging

“…Overall, at the beginning stage of the formation of Pt NC aggregates, hydroxyl-, thiol-, and amine-groups in Hb can be coordinated with Pt (IV) ions and entrapped them, leading to the reduction of Pt (IV) to Pt (II)-X complexes (X: thiol, carboxyl, amine groups), followed by reduction of the oligomeric Pt (II)-X complexes to Pt (0) atoms via tyrosine/tryptophan residues under basic condition (~pH ∼ 12), and their subsequent sequestration by Pt(II)-X complexes. After a fast reduction of platinum ions, Pt 6 and Pt 16 clusters are actively formed, and small Pt nanoparticles are subsequently formed mainly by coalescence and aggregation of Pt(0)@Pt(II)−Hb NCs (nucleation-dominant formation period); additionally, the intra- and inter-complex platinophilic Pt(II)···Pt(II) interactions increase the degree of aggregation and/or the oligomerization of Pt(II)–X complexes, whereby the intramolecular vibrations and rotations of the complexes are restricted which blocks the non-radiative pathway and activates radiative decay, consequently, results in enhancing the luminescence 28 – 30 , 48 , 49 . This was further confirmed by XPS Pt 4 f spectra in which the intensity ratio of Pt(0) to Pt(II) peaks increased distinctly from 1 day to 25 days (Fig.…”

Phosphorescent Modulation of Metallophilic Clusters and Recognition of Solvents through a Flexible Host-Guest Assembly: A Theoretical Investigation

“…The geometrical parameters of the ground state (S 0 ) for clusters I , II , and III at various calculated levels are in good agreement with their experimental X-ray structures, respectively. After further extensive testing, PBE0/BS1 was employed in the subsequent qualitative analysis as it was found to be time-economical and reliable to evaluate the geometrical, electronic, and spectral properties of weakly bound metal complexes ( Table S1, see SI ) [ 42 , 43 , 44 , 79 , 80 ].…”