Coarse and Fine Tuning of the Electronic Energies of Triimineplatinum(II) Square-Planar Complexes

Abstract

[Pt(tbtrpy)X]Y complexes (tbtrpy = 4,4',4' '-tBu3-2,2';6',2' '-terpyridine) exhibit charge-transfer absorption bands that can be drastically red-shifted to long-wavelength visible absorptions with arylthiolates as X. Further extension to the near-IR (NIR) region is achieved with 7,7,8,8-tetracyanoquinodimethane (TCNQ-) as Y-, resulting in black absorbers with continuous UV-vis-NIR absorptions and opening up potential applications in energy research.

Square-Planar Pd(II), Pt(II), and Au(III) Terpyridine Complexes: Their Syntheses, Physical Properties, Supramolecular Constructs, and Biomedical Activities

“…Chen et al 134 reported unique black absorbers with continuous UV-vis-NIR absorptions by simply changing the counterion and the co-ligand of the [Pt(t-Bu 3 -tpy)(Cl)][Cl] to [Pt(t-Bu 3 -tpy)(R-PhS)][TCNQ] complexes (TCNQ ) 7,7,8,8-tetracyano-quinodimethane; R ) 4-Me, 4-Cl, 3,4-diMe, and 2,5-diOMe) for possible conducting, magnetic, and solar cell applications. The crystal structure of 108 revealed short-range π-π interactions between Pt(II) cation and TCNQ anion with interplanar distances of 3.5 Å ( Figure 48A).…”

Solvent-tuned charge-transfer properties of chiral Pt(ii) complex and TCNQ˙− anion adducts

“…It can be speculated that the molecules are packed more closely in Form-H than in Form-M, therefore they induce a stronger donor-toacceptor charge transfer interaction and result in further absorption into the near-IR region. 47,48 Other than the differences in color and absorption, a distinct difference in the degree of crystallinity is observed between the two solid species (Fig. 2).…”

“…S1 †), which is the characteristic absorption of the TCNQc À anion. [38][39][40][41][42]47 Additionally, EPR spectra have been measured, and the g-factors of Form-M (g ¼ 2.003) and Form-H (g ¼ 2.004) are almost the same (Fig. S2 †), which is attributed to the unpaired electron of the TCNQc À radical anion.…”

“…[44][45][46] In general, the TCNQc À anion interacts with other cations to form CT adducts through p-p and hydrogen-bonding interactions; CT adducts containing Pt(II) complexes and TCNQc À would be of special interest because effective Pt-p contacts may be found, therefore leading to more interesting spectroscopic, magnetic and conductive properties. 47 Due to intensive charge transfer interactions between Pt(II) complexes and TCNQc À , their adducts exhibit continuous UV-vis-NIR absorptions spanning ca. 200-1500 nm, and the lowest energy absorption is a characteristic band from a donor/acceptor charge transfer transition that is absent in the absorption spectra of dissociated molecules of the donor or acceptor.…”

“…200-1500 nm, and the lowest energy absorption is a characteristic band from a donor/acceptor charge transfer transition that is absent in the absorption spectra of dissociated molecules of the donor or acceptor. 47 Given their strong absorptions across the visible-NIR region, these adducts can serve as competitive candidates for black body absorbers, opening up potential applications in wide band gap semiconductors and solar cells. 48 In previous work, we have investigated vapor-, solvent-, mechano-, redox-and temperature-induced structural and spectroscopic switches involving chiral square-planar Pt(II) complexes.…”