Pt^IIDiimine Chromophores with Perfluorinated Thiolate Ligands:  Nature and Dynamics of the Charge-Transfer-to-Diimine Lowest Excited State

Abstract

The synthesis of new Pt(II) diimine complexes bearing perfluorinated thiolate ligands, Pt(II)(NN)(4-X-C(6)F(4)-S)(2), where NN = 2,2'-bipyridine or 1,10-phenanthroline and X = F or CN, is reported, together with an investigation of the nature and dynamics of their lowest excited states. A combined UV-vis, (spectro)electrochemical, resonance Raman, and time-resolved infrared (TRIR) study has suggested that the HOMO is mainly composed of thiolate(pi)/S(p)/Pt(d) orbitals and that the LUMO is largely localized on the pi*(diimine) orbital, thus revealing the [charge-transfer-to-diimine] nature of the lowest excited state. An enhancement of the thiolate ring vibrations, C-F vibrations, and the vibration of the CN-substituent on the thiolate moiety was observed in the resonance Raman spectra, whereas no such enhancement was seen for the nonfluorinated analogues. Thus, the introduction of fluorine substituents on the thiolate moiety probably leads to a more pronounced contribution of the intrathiolate modes to the HOMO compared to the analogous complexes with nonfluorinated thiolates. Furthermore, the introduction of the p-CN group into the thiolate moiety has allowed the dynamics of the lowest excited state of Pt(bpy)(4-CN-C(6)F(4)-S)(2) to be monitored by picosecond TRIR spectroscopy. The dynamics of the lowest [charge-transfer-to-diimine] excited state are governed by ca. 2-ps vibrational cooling and 35-ps back electron transfer.

Palladium Complexes with the SC6F4H‐4 Ligand – Synthesis, Spectroscopy, and Structures

“…A closer look reveals that the intermolecular distances are 3.65-4.15 Å, which, together with the observed offset of the aromatic rings, points to only a very weak attractive interaction. Comparison with the structures of the related complexes [(bpy)Pt(SC 6 F 5 ) 2 ] (monoclinic, P2 1 /n) [25] and [(bpy)Pt{SC 6 F 4 (CN-4)} 2 ] (triclinic, P1), [23] which exhibit markedly different stacking patterns, leaves the impression that the crystal structures are not governed by these interactions. The shortest intramolecular stacking distance of 3.468(5) Å is found for [(bpy)Pd-(SC 6 F 4 H-4) 2 ], as shown in Figure 2; the other distances are far longer (Table 3).…”

Structure and Ultrafast Dynamics of the Charge-Transfer Excited State and Redox Activity of the Ground State of Mono- and Binuclear Platinum(II) Diimine Catecholate and Bis-catecholate Complexes: A Transient Absorption, TRIR, DFT, and Electrochemical Study

“…Picosecond TRIR Studies. TRIR [65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84] state directly. The spectrum after 1 ps shows a bleach of the parent ν(CO) of the amide group at 1640 cm -1 and formation of a transient band at 1624 cm -1 as resolved by a multi-Lorentzian fit to the data ( Figure 11).…”

[2,2′-Bipyridyl]platinum(II) Complexes with Fluorinated Benzenethiolate Ligands: Synthesis and Structural Elucidation

“…The reaction of one equivalent of the lead salt of the corresponding thiolate [Pb(SR F ) 2 ] (SR F ¼ 2 SC 6 F 5 , 2 SC 6 F 4 -4-H) with one equivalent of [Pt(bpy)(Cl) 2 ] afford complexes [Pt(bpy)(SC 6 F 5 ) 2 ] (1) [15,39] and [Pt(bpy)(SC 6 F 4 -4-H) 2 ] (2) in good yields. Both compounds were obtained as analytically pure products from recrystallization of CH 2 Cl 2 /MeOH solvent systems.…”