Paul Animesh, Das Soumi, Bar Manoranjan, Baitalik Sujoy
Inorganic Chemistry Section, Department of Chemistry, Jadavpur University, Kolkata 700032, India.
Dalton Trans. 2021 Oct 26;50(41):14872-14883. doi: 10.1039/d1dt02544a.
This paper deals with a thorough investigation of pH-induced tuning of the ground and excited state photophysical as well as electrochemical behaviours of two series of our recently reported homo- and heterotrimetallic complexes of the type [(bpy)Ru(d-HIm-t)M(t-HIm-d)Ru(bpy)] and [(bpy)Os(d-HIm-t)M(t-HIm-d)Os(bpy)] (M = Ru and Os) derived from a heteroditopic bpy-tpy (d-HIm-t) type bridging ligand through the exploitation of their second coordination sphere. A small bathochromic shift of the absorption and emission spectral band along with substantial alteration of emission intensity and lifetime of the triads is noted upon deprotonation of the NH motifs at elevated pH values. The lowering of the half wave potential of a M/M couple is also observed upon removal of the NH protons. Both ground and excited state p values of the triads are estimated from their absorption/emission pH spectral profiles. In addition, the variation of the free energy change (Δ) and the rate of intercomponent energy transfer () in the triads upon stepwise deprotonation of the NH motifs are also addressed in the present study.
本文通过利用其二配位球，对我们最近报道的两类同核和异核三金属配合物[(bpy)Ru(d - HIm - t)M(t - HIm - d)Ru(bpy)]和[(bpy)Os(d - HIm - t)M(t - HIm - d)Os(bpy)]（M = Ru和Os）的基态和激发态光物理以及电化学行为的pH诱导调谐进行了深入研究。这些配合物由一种异双位点bpy - tpy (d - HIm - t)型桥联配体衍生而来。在较高pH值下，当NH基序去质子化时，观察到三联体的吸收和发射光谱带出现小的红移，同时发射强度和寿命也发生显著变化。去除NH质子后，还观察到M/M电对的半波电位降低。根据三联体的吸收/发射pH光谱曲线估算了它们的基态和激发态p值。此外，本研究还探讨了NH基序逐步去质子化时三联体中自由能变化(Δ)和组分间能量转移速率()的变化。
