Bennett Trystan, Adnan Rohul H, Alvino Jason F, Golovko Vladimir, Andersson Gunther G, Metha Gregory F
Department of Chemistry, University of Adelaide , North Terrace, Adelaide, South Australia 5005, Australia.
Inorg Chem. 2014 May 5;53(9):4340-9. doi: 10.1021/ic403040u. Epub 2014 Apr 23.
High-quality far-IR absorption spectra for a series of ligated atomically precise clusters containing Ru3, Ru4, and AuRu3 metal cores have been observed using synchrotron radiation, the latter two for the first time. The experimental spectra are compared with predicted IR spectra obtained following complete geometric optimization of the full cluster, including all ligands, using DFT. We find strong correlations between the experimental and predicted transitions for the low-frequency, low-intensity metal core vibrations as well as the higher frequency and intensity metal-ligand vibrations. The metal core vibrational bands appear at 150 cm(-1) for Ru3(CO)12, and 153 and 170 cm(-1) for H4Ru4(CO)12, while for the bimetallic Ru3(μ-AuPPh3)(μ-Cl)(CO)10 cluster these are shifted to 177 and 299 cm(-1) as a result of significant restructuring of the metal core and changes in chemical composition. The computationally predicted IR spectra also reveal the expected atomic motions giving rise to the intense peaks of metal-ligand vibrations at ca. 590 cm(-1) for Ru3, 580 cm(-1) for Ru4, and 560 cm(-1) for AuRu3. The obtained correlations allow an unambiguous identification of the key vibrational modes in the experimental far-IR spectra of these clusters for the first time.
利用同步辐射观察到了一系列含有Ru3、Ru4和AuRu3金属核的连接原子精确簇的高质量远红外吸收光谱，后两者是首次观察到。将实验光谱与使用密度泛函理论（DFT）对包括所有配体的完整簇进行完全几何优化后得到的预测红外光谱进行了比较。我们发现，对于低频、低强度的金属核振动以及高频和高强度的金属-配体振动，实验和预测跃迁之间存在很强的相关性。Ru3(CO)12的金属核振动带出现在150 cm(-1)处，H4Ru4(CO)12的金属核振动带出现在153和170 cm(-1)处，而对于双金属Ru3(μ-AuPPh3)(μ-Cl)(CO)10簇，由于金属核的显著重组和化学成分的变化，这些振动带移至177和299 cm(-1)处。计算预测的红外光谱还揭示了预期的原子运动，这些运动导致了Ru3在约590 cm(-1)、Ru4在580 cm(-1)以及AuRu3在560 cm(-1)处出现金属-配体振动的强峰。所获得的相关性首次使得能够在这些簇的实验远红外光谱中明确识别关键振动模式。
