Structural Elucidation of Selective Solvatochromism in a Responsive‐at‐Metal Cyclometalated Platinum(II) Complex

Abstract

We report the synthesis, characterization, and spectroscopic investigations of a new responsive‐at‐metal cyclometalated platinum(II) complex. With mild chemical oxidants and reductants, it was possible to obtain the same complex in three different oxidation states and each of these complexes was structurally characterized by single‐crystal X‐ray diffraction. We discovered that the platinum(II) complex displays strong solvatochromism in the solid state, which can be attributed to modulation of Pt⋅⋅⋅Pt interactions that results in switching between optical and photoluminescent states. Incorporating responsive‐at‐metal species as dynamic components in nanostructured materials might facilitate response amplification, sensing, actuation, or self‐healing processes.

Two cyclometalated Pt(ii) complexes showing reversible phosphorescence switching due to grinding-induced destruction and crystallization-induced formation of supramolecular dimer structure

“…In summary, two dithienylethene-based Pt(II) complexes [Pt(dfppy)(pbdtmi)]PF 6 (1) and [Pt(ppy)(pbdtmi)]PF 6 (2) have been designed and synthesized. Their crystal structures indicate that two neighboring [Pt(dfppy/ppy)(pbdtmi)] + cations connect each other through p/p stacking interaction, thus forming supramolecular dimer structure (Fig.…”

“…Based on DTE-based N^N ancillary ligands (Scheme S2 †), some alkynylplatinum(II) diimine complexes have been reported, in which the molecular structures of these DTE-bsed N^N ligands can signicantly modulate the luminescence and the photochromism of the related Pt(II) complexes in solution. 23,25 Inspired by these studies, we synthesized a new DTEbased N^N ancillary ligand 2-pyridyl-4,5-bis(2,5-dimethyl(3thienyl))-1-methyl-imidazole (pbdtmi, see Scheme 1) and its cyclometalated Pt(II) complexes [Pt(dfppy)(pbdtmi)]PF 6 (1) and [Pt(ppy)(pbdtmi)]PF 6 (2) in which dfppyH ¼ 2-(2,4-diuorophenyl)-pyridine, and ppyH ¼ 2-phenyl-pyridine (Scheme 1). Besides possible photochromism, ligand pbdtmi has three structure advantages.…”

“…Synthesis of [Pt(dfppy)(pbdtmi)]PF 6(1) To a solution of pbdtmi (0.1 mmol, 0.0380 g) and [Pt(dfppy)(SEt 2 )Cl] (0.1 mmol, 0.0440 g) in CH 2 Cl 2 (6 mL) was added AgPF 6 (0.1 mmol, 0.0253 g). The reaction mixture was heated in an oil bath (40 C) for one day, and then 30 mL of CH 2 Cl 2 was added.…”

Chromic Platinum Complexes Containing Multidentate Ligands

“…From the rich list of vapochromic Pt(II) complexes, 12 is the only one that bears a tetradentate ligand, namely an oxo‐bridged bis(phenylpyridine) framework (Figure 8a) [75] . In the solid state, 12 shows little deviation from a square‐planar geometry, which enables it to assemble into dimers.…”

Selectivity and competition between N–H and C–H bond activation using an organoplatinum (II) complex

“…[27] Understanding the mechanism of these bond activations is an important area of research. Although cyclometalation reactions via C-H bond activation have been widely studied, and different classes of cycloplatinated and rollover cycloplatinated complexes have been synthesized, [31][32][33][34][35][36][37][38][39][40][41][42] a detailed investigation when both N-H and C-H bonds are available for activation has not been reported for platinum complexes and is limited to a few studies for Ir and Co complexes. [43][44][45] In the present study, 2-(2 0 -pyridyl)benzimidazole (Hpbz) is selected as the ligand with both C-H and N-H to investigate its reaction with a dimethylplatinum (II) complex, (PtMe 2 (DMSO) 2 ), 1, (DMSO = dimethyl sulfoxide).…”