Molecular and electronic structures and photophysical properties of quadruply bonded dimetal complexes (M = Mo or W) supported by trans-arylethynylcarboxylate ligands where aryl = p-tolyl or 9-anthrancenyl†
Abstract
From the reactions between M2(TiPB)4, where TiPB = 2,4,6-triisopropylbenzoate and M = Mo or W, in C–Ar)2 have been prepared where Ar =
C), ν(CO2) and from 1400–1000 cm−1. Aided by density functional theory, (DFT) and time dependent DFT, the electronic structures of the ground state and the S1 and T1 states are described. The molybdenum compounds have short lived 1MLCT states, 1a ∼ 5.0 ps and 2a ∼ 10.5 ps, that undergo intersystem crossing to long lived 3MoMoδδ* states: 1a ∼ 101 μs and 2a ∼ 83 μs. The tungsten complexes show interesting time-resolved
C) region when compared with their ground state. Compound 1b shows ν(C
C) at 1975 cm−1 for the 1MLCT state which decays with τ ∼ 0.7 ps to ν(C
C) at 2000 cm−1 for the 3MLCT state. For 2b the 1MLCT is characterized by ν(C
C) at 2150 cm−1, τ ∼ 19 ps, and a very broad absorption with a maximum ∼1970 cm−1 which is proposed to arise from a low energy electronic transition. The 3MLCT state for 2b shows no evidence of ν(C
C) and is suggested to have an electron localized principally on the anthracenyl portion of the
- This article is part of the themed collection: In Celebration of David Cole-Hamilton's Career in Chemistry