On the intersystem crossing rate in a Platinum(ii) donor–bridge–acceptor triad

Abstract

The rates of ultrafast intersystem crossing in acceptor-bridge-donor molecules centered on Pt(II) acetylides are investigated. Specifically, a Pt(II) trans-acetylide triad NAP-≡-Pt-≡-Ph-CH2-PTZ [1], with acceptor 4-ethynyl-N-octyl-1,8-naphthalimide (NAP) and donor phenothiazine (PTZ),...

Direct Determination of the Rate of Intersystem Crossing in a Near-IR Luminescent Cr(III) Triazolyl Complex

“…This technique selectively reports on fluorescent excited states on the femtosecond timescale, therefore being ideally suited to monitor excitedstate processes involving a change in spin state, allowing the dynamics of ISC to be disentangled from those of other nonradiative excited-state events (e.g., IC, VC), something which is difficult to achieve by other spectroscopic means. 66,67 Indeed, fluorescence upconversion spectroscopy experiments have previously been used to good effect in determining the rate of ISC in the ubiquitous [Ru(bpy) 3 ] 2+ , arriving at a value of τ = 15 ± 10 fs following the observation of short-lived fluorescence from the Frank−Condon 1 MLCT state prior to ISC. 68 FLUPS spectra obtained for aerated acetonitrile solutions of 1 3+ following 400 nm, 40 fs excitation are shown in Figure 4.…”

“…Fluorescence upconversion spectroscopy experiments were performed in the Lord Porter Ultrafast Laser Laboratory at the University of Sheffield, using a setup that has been previously described in detail elsewhere. ,, Pertinent experimental information is as follows.…”

A stronger acceptor decreases the rates of charge transfer: ultrafast dynamics and on/off switching of charge separation in organometallic donor–bridge–acceptor systems

“…The rate of intersystem crossing of >(300 fs) −1 is similar to that reported recently for some Pt(II) trans-acetylides, 52 but two orders of magnitude higher than in the NAP-Pt-PTZ analogue. 53 Complex 3 in DCM does not show the broad near-IR emission from a 3 IL state observed in 1 and 2, suggesting the presence of a new excited state in 3 involving the PTZ unit: population of this state would offer an additional decay channel for the 3 IL state, quenching its emission. However, in hexane 2 and 3 show identical 3 IL emission (Fig.…”

Spin–vibronic mechanism at work in a luminescent square-planar cyclometalated tridentate Pt(ii) complex: absorption and ultrafast photophysics

“…[7][8][9][10][11][12] More recently, time-resolved (ps-fs) spectroscopy experiments were applied to mono-and bi-metallic Pt complexes in order to probe the interplay between nuclear and electronic motion, intersystem crossing and vibrational coherence in ultrafast processes. [13][14][15][16][17][18][19][20] This field of research opens the way to fine-tuning of the photoluminescent and charge transfer properties under stimuli such as light, electric field or a specific environment for the design of building blocks in the development of new functional and switchable materials. [21][22][23][24] Standard theoretical investigations, based on routine static density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations, are not up to the experimental challenges.…”