Nonlinear Absorbing Platinum(II) Diimine Complexes: Synthesis, Photophysics, and Reverse Saturable Absorption

Abstract

A series of platinum(II) diimine complexes with different substituents on fluorenyl acetylide ligands (1a-1e) were synthesized and characterized. The influence of the auxiliary substituent on the photophysics of these complexes has been systematically investigated spectroscopically and theoretically (using density functional theory (DFT) methods). All complexes exhibit ligand-centered (1)π,π* transitions in the UV and blue spectral region, and broad, structureless (1)MLCT/(1)LLCT (1a, 1b, 1d and 1e) or (1)MLCT/(1)LLCT/(1)π,π* (1c) absorption bands in the visible region. All complexes are emissive in solution at room temperature, with the emitting state is tentatively assigned to mixed (3)MLCT/(3)π,π* states. The degree of (3)π,π* and (3)MLCT mixing varies with different substituents and solvent polarities. Complexes 1a-1e exhibit relatively strong singlet and triplet transient absorption from 450 to 800 nm, at which point reverse saturable absorption (RSA) could occur. Nonlinear transmission experiments at 532 nm by using nanosecond laser pulses demonstrate that 1a-1e are strong reverse saturable absorbers and could potentially be used as broadband nonlinear absorbing materials.

trans-Bis(alkylphosphine) platinum(ii)-alkynyl complexes showing broadband visible light absorption and long-lived triplet excited states

“…Based on the transient absorption spectra, no triplet state equilibrium was observed for Pt-2. Thus we propose that the 3 [BDP*-p] state was quenched by the efficient triplet state energy transfer to 3 [BDP*-c]. This photophysical process is different from that of Pt-1.…”

Influence of a Naphthaldiimide Substituent at the Diimine Ligand on the Photophysics and Reverse Saturable Absorption of PtII Diimine Complexes and Cationic IrIII Complexes

“…[39] The synthesis of ligand 6 was reported by our group previously. [24] Substitution of the Cl coligands in precursors 5 and 7 with the acetylide ligand 6 in the presence of CuI and diisopropylamine (DIPA) gave the Pt II complexes 1 and 2. The dinuclear dichlorido-bridged Ir III complexes 9 and 10 were converted into the heteroleptic complexes 3 and 4 by breaking the Cl bridge and coordinating them with the N ∧ N ligand 8.…”

“…[18,27] In addition to the aforementioned work, Weinstein's group reported a detailed study on the excited state dynamics of a Pt II diimine chloride complex bearing a strong electron-withdrawing naphthaldiimide (NDI) substituent on the diimine ligand. [39] It was found that there is little electronic interaction between the Pt(phen)Cl 2 [14,18,20,23,24,27] In this work, we synthesized a Pt II diimine complex and two cationic Ir III complexes bearing the NDI motif on the diimine (N ∧ N) ligand (complexes 2-4 in Figure 1). Pt II complex 1, which contains the 1,10-phenanthroline ligand, was synthesized to be a reference compound for the Pt II complex 2 in order to better understand the role of NDI in the presence of the BTF acetylide ligands.…”

Synthesis, spectral and redox switchable cubic NLO properties of chiral dinuclear iron cyanide/isocyanide-bridged complexes

“…To pursue the relationship between molecular structure and NLO properties in this field, large numbers of organometallic complexes with good NLO properties have been synthesized and studied over the past thirty years. 1,2 In particular, organometallic mixed-valence complexes, usually containing low-energy absorption bands in the Vis-NIR region, exhibit similar properties to organic donoracceptor molecules, which could present a good NLO response. 3,4 In 1993, Laidlaw and co-workers studied the second-order response of two cyanide-bridged organometallic mixed-valence complexes by the hyper-Rayleigh scattering technique, and found that those complexes show a large first hyperpolarizability, which is attributed to the intervalence charge-transfer (IVCT) states in the mixed-valence complexes and the near-resonant enhancement caused by the proximity of the input laser beam and IVCT transition frequencies.…”

“…UV-Vis-NIR (CH 2 Cl 2 ): λ max , nm (ε, M −1 cm −1 ): 330 (3060). ESI-MS m/z: 1078.3[2] + .Synthesis of complex 2 2+ . The synthesis method of complex 2 2+ is similar to that of complex 1 2+ .…”