Cyclometalated Platinum(II) Complexes with Nitrile and Isocyanide Ligands: Synthesis, Structure, and Photophysical Properties

Cyclometalated Platinum(II) Complexes with 10-(Aryl)phenoxarsine Ligands: Synthesis, Structure, and Photophysical Properties

“…In all structures, the platinum site displays a slightly distorted square-planar geometry with a cis (N,X) disposition of the N atom of the 2-phenylpyridinate ligand and the halo ligand. It is consistent with the NMR data and X-ray diffraction data obtained for similar C^N-cyclometalated platinum­(II) complexes with P- and N-containing monodentate ligands. ,,,,,,,,− ,,− The main contribution to the distortion in complexes 2 – 5 and 8 is made by the tight chelate angle ∠N12–Pt1–C11 = 80.32–80.92°, which results in nonlinear trans axes (∠N12–Pt1–As1 = 171.42–177.76° and ∠C1–Pt1–X1 = 170.21–173.48°). The Pt1–N12 distances in complexes 2 – 5 and 8 are close to those found in the Cambridge Structural Database for similar complexes (Table S7).…”

“…For example, [Pt(ppy)Cl(L)] complexes exhibit a completely structured emission band centered at λ = 505 nm (L = phenylpyridine), 20,17 559 nm (L = 3-tert-butylpyrazole), 21 and 470−490 nm (L = NCR, R = t-Bu, Bn, Ph). 22 For [Pt(ppy)X(PPh 3 )] complexes, a decrease in the emission efficiency was observed (F > Cl > Br > I) and ascribed to an increase in the XLCT character of the emissive triplet state. 23 Unlike C^N-cyclometalated complexes [Pt(ppy)X(L)] with ancillary monodentate phosphine and N-containing ligands (L), there are no data in the literature on the synthesis and photophysical properties of their analogues with arsine ligands.…”

“…This means that the luminescence of [Pt­(ppy)­X­( L )] strongly depends on the cyclometalating ligand and the electronic properties of the substituents. ,, The ancillary pnictogene and halo ligands have no significant influence on the emission but finely tune the emission characteristics. For example, [Pt­(ppy)­Cl­( L )] complexes exhibit a completely structured emission band centered at λ = 505 nm ( L = phenylpyridine), , 559 nm ( L = 3- tert -butylpyrazole), and 470–490 nm ( L = NCR, R = t -Bu, Bn, Ph) . For [Pt­(ppy)­X­(PPh 3 )] complexes, a decrease in the emission efficiency was observed (F > Cl > Br > I) and ascribed to an increase in the XLCT character of the emissive triplet state …”

Multistimuli-Responsive Properties of Aggregated Isocyanide Cycloplatinated(II) Complexes

“…Their structural analyses reveal the expected distorted square planar geometry with the isocyanide ligand in the trans position with respect to the nitrogen of the cyclometalated groups (Figures and ). All distances and angles are comparable to those observed in related complexes. ,, …”

“…These complexes 1 are rather soluble in common organic solvents. Spectroscopic analysis and X-ray diffraction (XRD) of crystals of 1a and 1b from different solvents (see below) reveal that complexes 1 display the stereochemistry shown in Scheme 1 with CNBu t occupying the trans position to the nitrogen of the C ∧ N ligand, similarly to other chloride–isocyanides published 14a , 19a , 21 and consistent with the lower trans influence of Cl – compared to the CNBu t ligand. They exhibit one ν(Pt–Cl) absorption at 289 cm –1 , consistent with a terminal Pt–Cl bond trans to C, and one absorption at 2207 1a and 2205 cm –1 1b , assignable to ν(C≡N) of terminal CNBu t , which is shifted to higher frequencies with respect to the free ligand (2125 cm –1 ).…”