Purkayastha Siddhartha K, Rohman Shahnaz S, Parameswaran Pattiyil, Guha Ankur K
Advanced Computational Chemistry Centre, Cotton University, Panbazar, Guwahati, Assam, 781001, India.
Department of Chemistry, National Institute of Technology Calicut, Kozhikode, 673601, India.
Phys Chem Chem Phys. 2024 Apr 24;26(16):12573-12579. doi: 10.1039/d4cp00908h.
Transition metal-carbonyl bonds are rationalized by M ← CO σ donation and M → CO π back donation where the d orbital of the transition metal is involved. This bonding model provided by Dewar, Chatt and Duncanson (DCD) has rationalized many transition metal-ligand bonds. The involvement of p orbital in such a DCD model can be intriguing. Alkaline earth metals with nsnp configuration may appear suitable as nsnp excitation has been recognized in many complexes. Herein, a theoretical study is presented for the Be(CO) ( = 1-4) complex to verify this assumption. Detailed electronic structure analyses confirmed the involvement of the p orbital of beryllium in M → CO π back donation, thereby supporting the hypothesis. EDA-NOCV results reveal that the π-back donation from the central Be atom to CO ligands significantly predominates over the σ donation from the ligands for both Be(CO) and Be(CO). Our calculations reveal that Be(CO) is the highest carbonyl that may be experimentally detected.
过渡金属 - 羰基键可通过M←CO σ给予和M→CO π反馈给予来解释，其中过渡金属的d轨道参与其中。由杜瓦（Dewar）、查特（Chatt）和邓肯森（Duncanson）（DCD）提出的这种键合模型解释了许多过渡金属 - 配体键。p轨道在这种DCD模型中的参与可能很有趣。具有nsnp构型的碱土金属似乎适合，因为在许多配合物中已经认识到nsnp激发。在此，对Be(CO) （n = 1 - 4）配合物进行了理论研究以验证这一假设。详细的电子结构分析证实了铍的p轨道参与M→CO π反馈给予，从而支持了这一假设。EDA - NOCV结果表明，对于Be(CO)₄和Be(CO)₂，中心Be原子向CO配体的π反馈给予明显超过配体的σ给予。我们的计算表明，Be(CO)₂是可能通过实验检测到的最高羰基化合物。
