我們使用密度泛函理論（TD-DFT）與spin–orbit coupling effect（SOC effect）來模擬計算把YD2-o-C8作為骨架的porphyrin染料中心金屬Zn換成Ru和Os，使用Cl-或PPh(OMe)2連接中心金屬，成為六配位的porphyrins，研究染料的電子結構和吸收光譜。具有兩個Cl-配位的Ru-和Os-porphyrins在near IR / IR區域邊緣顯示出較弱的吸收，這在原始的YD2-o-C8染料中沒有觀察到的。在長波長邊緣有吸收是源自金屬到受體的電荷轉移(MACT)，並進一步由具有重的Ru和Os原子的SOC effect造成紅位移的現象。另一方面，使用PPh(OMe)2 作為ligands的染料在near IR區域不產生吸收，結果可得PPh(OMe)2 ligand能穩定修飾Ru-和Os-porphyrins的“ t2g”軌道。另外也觀察到PPh(OMe)2連接的porphyrins有SOC effect。這項研究表明，將Ru和Os重原子引入以Cl-作為ligands的porphyrins可以誘導在長波長吸收的金屬到受體的電荷轉移，並進一步增強SOC effect，使吸收紅位移。研究結果為設計長波長躍遷提供了一種新方法，同時又保留了原有的染料骨架。;We investigate the electronic structures and absorption spectra for Ru- and Os-porphyrins ligated with Cl− or PPh(OMe)2 using an Zn-based YD2-o-C8 skeleton as well as YD2-o-C8 and YD2 dyes by time-dependent density functional theory (TD-DFT) with spin–orbit coupling (SOC) interactions. The Ru- and Os-porphyrins modified with two Cl− as ligands exhibit a weak absorption onset in the near IR/IR region, which is not observed in that of original YD2-o-C8 dye. The long wavelength absorption edge originates from the metal to acceptor charge transfer MACT and is further red-shifted from SOC with heavy Ru and Os atoms. On the other hand, the PPh(OMe)2 ligands stabilizing the “t2g” orbitals of the modified Ru- and Os-porphyrins do not induce absorption in the near IR region. However, SOC is also observed for PPh(OMe)2 ligated Ru- and Os-porphyrins. This study shows that the introduction of heavy Ru and Os atoms into porphyrin skeleton with Cl- as ligands can induce long wavelength metal-to-acceptor charge transfer and further enhance the SOC, red-shifting the absorption. This result offers a new approach for designing long wavelength transitions, while remaining the original dye framework.
