本研究為利用變溫拉曼光譜儀偵測異核直線型金屬串錯合物Ru2M(dpa)4Cl2，(dpa = di(2-pyridyl)amide，M = Ni、Cu)及其各自的氧化物晶體的拉曼光譜，並搭配密度泛函理論計算 (Density functional theory, DFT)，指認金屬串錯合物的分子結構、振動模式以及電子能階。由於[Ru2]具有多種能量相近、不同價數、不同電子組態的能階，吾人分別對四種金屬串錯合物進行變溫拉曼光譜以及吸收光譜的量測，已知Ru2Ni(dpa)4Cl2的基態為五重態，電子組態為(π*)2(δ*)1、 (dx2–y2)1，金屬價數為[Ru2]5+[Ni]+，而其在500 K時會發生電子轉移，電子由Ni轉移至[Ru2]，金屬價數變為[Ru2]4+[Ni]2+，但仍為五重態。而[Ru2Ni(dpa)4Cl2](PF6)在77 K至423 K之間其光譜不會有變化，皆維持在同一個六重態，電子組態為(π*)2(δ*)1、 (dx2–y2)1(dxy)1，金屬價數為[Ru2]5+Ni2+。Ru2Cu(dpa)4Cl2的基態為四重態，電子組態為(π*)2(δ*)1，同樣會在500 K時發生電子轉移，其金屬價數會從[Ru2]5+Cu+變為[Ru2]4+Cu2+，而其電子態仍然維持在四重態。在[Ru2Cu(dpa)4Cl2](PF6)的部分，其在77 K至297 K的溫度範圍內光譜同樣不變，而其基態為五重態，電子組態為(π*)2(δ*)1、 (dx2–y2)1，金屬價數為[Ru2]5+Cu2+，而在此研究中吾人修正了先前對其Ru–Ru伸縮振動模式的指認，由326 cm–1修正為348 cm–1。

We used temperature-controlled Raman spectroscopy to study the vibrational structures of linear heteronuclear metal-string complexes [Ru2Ni(dpa)4Cl2]0,1+ and [Ru2Cu(dpa)4Cl2]0,1+ (dpa = di(2-pyridyl)amide). From the Raman spectra, Ru–Ru stretching band positions, combining the results of density functional theory calculations, EPR, magnetic measurements, and electronic absorption data, we resolved their vibrational structures and some low-lying electronic states. Complex Ru2Ni(dpa)4Cl2 with a quintet as the ground state, an electron configuration (π*)2(δ*)1–(dx2–y2)1 and [Ru2]5+[Ni]+ core, has the Ru–Ru stretching band, "ν" _"Ru–Ru" , at 333 cm–1 at near 100 K, decreasing to 320 cm–1 at 573 K and 317 cm–1 at 623 K. We proposed that intramolecular charge transfer states with configurations of (π*)2(δ*)2 and (π*)3(δ*)1 arose to have [Ru2]4+[Ni]2+ core at high temperatures. For the oxidized form [Ru2Ni(dpa)4Cl2](PF6) between 77 K and 423 K, "ν" _"Ru–Ru" = 335 cm–1 was unchanged. In Ru2Cu(dpa)4Cl2, "ν" _"Ru–Ru" = 325 cm–1 at 77 K decreasing to 321 cm–1 at 500 K indicating similar charge-transfer reaction occurred at high temperatures. Finally, [Ru2Cu(dpa)4Cl2](PF6) between 77 K and 373 K, has a quintet ground state and an electron configuration (π*)2(δ*)1–(dx2–y2)1 and a [Ru2]5+Cu2+ core. With a [Ru2]5+ core, its "ν" _"Ru–Ru" = 348 cm–1 having the greatest Ru–Ru bond strength among the four complexes studied.

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