Host–Guest and Photophysical Behavior of Ti₈L₁₂ Cube with Encapsulated [Ti(H₂O)₆] Species

Abstract

Titanium-based coordination cages could be interesting for both supramolecular and photophysical chemistry. This work reports an unprecedented host-guest system, [Ti(H O) ]@Ti L , which is comprised of the first Ti-based coordination cube and the unusual titanium aquo species. Due to the abundant intra-cube O-H⋅⋅⋅O hydrogen bonds, the [Ti(H O) ]@Ti L complex is rather stable both in solid and solution states, confirmed by X-ray diffraction and ESI-MS analysis. The encapsulated [Ti(H O) ] species shows influence on the light absorption, photoluminescent, and photocurrent properties. Moreover, ultrafast transient absorption spectroscopy has been applied to study the photodynamics of both free and [Ti(H O) ] guest encapsulated Ti L cube, confirming that the host-guest system produces a slightly longer-lived excited state. Therefore, this work presents the first [Ti L ] cube with unusual [Ti(H O) ] guest and also provides an interesting supramolecular model for the host-guest photophysical study.

Isomerism in Titanium‐Oxo Clusters: Molecular Anatase Model with Atomic Structure and Improved Photocatalytic Activity

“…The kinetics probed at the GSB is shown in Figure b and indicates very fast decay on the ps timescale. This is similar to our previous observations in PTC clusters and is likely due to the very strong vibronic coupling in these clusters leading fast nonradiative decay. The TA spectra of PTC‐49 H are similar to those of PTC‐49 V (Figure S12a).…”

Syntheses and Structural Studies of a Series of Ti4(embonate)6-based Complexes

“…随后, 在 2008 年, 该课题组 [32] 在前面的研究基础上, 对配体进行了修饰, 引入手性分 子(1-苯乙基异氰酸酯), 合成了首例纯手性的钛-有机四 面体笼. 2018 年, 本课题组 [33] 利用 2,6-二羟基苯甲酸和 Ti(IV)离子反应, 合成了首例立方烷型的 Ti 8 笼.…”

Isomerism in Titanium‐Oxo Clusters: Molecular Anatase Model with Atomic Structure and Improved Photocatalytic Activity

“…In order to rationalize the observations above,u ltrafast transient absorption (TA) measurements were carried out on the isomeric PTC-49 V and PTC-49 H .F igure 4a shows the TA spectra of PTC-49 V at indicated delays following the excitation by a3 50 nm pump pulse with an excitation density of 560 mJcm À2 .T he obtained TA spectra are dominated by ground state bleach (GSB) and excited state absorption (ESA) features.T he kinetics probed at the GSB is shown in Figure 4b and indicates very fast decay on the ps timescale. This is similar to our previous observations in PTC clusters [32] and is likely due to the very strong vibronic coupling in these clusters leading fast nonradiative decay.T he TA spectra of PTC-49 H are similar to those of PTC-49 V (Figure S12a). Its GSB kinetics is also plotted in Figure 4b,w hich is qualitatively similar to but slightly longer-living than that of PTC-49 V .T hree-exponential fits to these kinetics reveal that the PTC-49 V has decay time constants (and their relative amplitudes) of 2.74 ps (62.3 %), 10.9 ps (28.6 %), and 1780 ps (9.10 %);t hese numbers are 3.78 ps (79.0 %), 48.3 ps (7.40 %), and 4340 ps (13.6 %) for PTC-49 H .T hese short lifetimes explain the weak photocurrents observed in Figure 3b and are consistent with the slightly higher photocurrent response of PTC-49 H than that of PTC-49 V .…”