TDDFT study on electronic excitations and first hyperpolarizabilities of mixed-metal carbonyl clusters Mo_nIr_4-n(μ-CO)₃(β⁵-Cp)_n (n = 1,2,3)

Abstract

A series of mixed-metal carbonyl clusters, Mo_nIr_4-n(μ-CO)₃(CO)_9-n(η⁵-Cp)_n (n = 1, 2; Cp = C₅H₄Me, C₅HMe₄, C₅Me₅, C₅H₅), have been investigated using the TDDFT method. The results estimated the medium magnitude of the first static hyperpolarizabilities (β _tot  ∼ 2 × 10⁻³⁰esu) of these tetrahedral mixed-metal clusters, most of which originate from the intra-cluster charge transfer of the metal skeleton consisting of polar metal–metal interactions. No direct contributions of the Cp ligands to the relevant charge transfer were found, but the cooperative effect between the metal centres and Cp ligands impacts the β. Based on these studies a mixed-metal cluster Mo₃Ir(μ-CO)₃(CO)₇(η⁵-Cp)₂ was designed that exhibits enhanced first hyperpolarizability.

Keywords:

• TDDFT
• UV-Vis
• Nonlinear optical
• Cyclopentadienyl
• Transition metal

Acknowledgements

We thank the National Science Foundation of China (20573114) for financial support. And we also acknowledge use of the computer facility in the Virtual Laboratory for Computational Chemistry and Supercomputing Center of CNIC in Beijing.