Abstract
We report a robust and modular synthetic route to heterometallic rare earth-transition metal complexes. We have used the redox-active bridging ligand 1,10-phenathroline-5,6-dione (pd), which has selective N,N' or O,O' binding sites as the template for this synthetic route. The coordination complexes [Ln(hfac)3(N,N'-pd)] (Ln = Y [1], Gd [2]; hfac = hexafluoroacetylacetonate) were synthesised in high yield. These complexes have been fully characterised using a range of spectroscopic techniques. Solid state molecular structures of 1 and 2 have been determined by X-ray crystallography and display different pd binding modes in coordinating and non-coordinating solvents. Complexes 1 and 2 are unusually highly coloured in coordinating solvents, for example the vis-NIR spectrum of 1 in acetonitrile displays an electronic transition centred at 587 nm with an extinction coefficient consistent with significant charge transfer. The reaction between 1 and 2 and VCp2 or VCpt2 (Cpt = tetramethylcyclopentadienyl) resulted in the isolation of the heterobimetallic complexes, [Ln(hfac)3(N,N'-O,O'-pd)VCp2] (Ln = Y [3], Gd [4]) or [Ln(hfac)3(N,N'-O,O'-pd)VCpt2] (Ln = Y [5], Gd [6]). The solid state molecular structures of 3, 5 and 6 have been determined by X-ray crystallography. The spectroscopic data on 3-6 are consistent with oxidation of V(ii) to V(iv) and reduction of pd to pd2- in the heterobimetallic complexes. The spin-Hamiltonian parameters from low temperature X-band EPR spectroscopy of 3 and 5 describe a 2A1 ground state, with a V(iv) centre. DFT calculations on 3 are in good agreement with experimental data and confirm the SOMO as the dx2-y2 orbital localised on vanadium.
Highlights
The cooperativity between metal centres in multimetallic complexes, clusters and polymeric species gives rise to very remarkable chemistry in a diverse range of fields.1 The potential applications of complexes containing both transition metals and lanthanides are significant
We note that while you can access [Ln(hfac)3] directly from Ln2O3, the synthesis requires the addition of chelating polyethers to prevent aggregation
We propose that the νCO at 1668 and 1661 cm−1 may result from the short contacts seen between the Ln metal centre and one pd-O atom of the neighbouring molecule (Fig. 3 and Electronic supplementary information (ESI)†)
Summary
The cooperativity between metal centres in multimetallic complexes, clusters and polymeric species gives rise to very remarkable chemistry in a diverse range of fields. The potential applications of complexes containing both transition metals and lanthanides are significant. The cooperativity between metal centres in multimetallic complexes, clusters and polymeric species gives rise to very remarkable chemistry in a diverse range of fields.. The potential applications of complexes containing both transition metals and lanthanides are significant. In particular there is research interest in the design of rare earth-transition metal singlemolecule magnets (SMM) and catalysts.. The chemistry of multimetallic complexes containing f-elements is significantly less well developed than that of transition metals. This is attributable to the fact that the directed synthesis of f–d complexes is non-trivial. The inspiration for our approach was the Tb analogue of the [{(SiMe3)2N}Ln]2N2K system. This complex was remarkable both for the (N2)3–
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
