Disturbance of intermolecular forces: eutectics as a new tool for the preparation of vapor-phase deposition precursors

Abstract

The volatile bis(tert-butylimido)dichloromolybdenum(VI) compounds, (tBuN)₂MoCl₂·dad (dad = 1,4-di-tert-butyl-1,3-diazabutadiene) (1) and [(tBuN)₂MoCl(μ-Cl)·(tBuNH₂)]₂ (2), form a eutectic, with a two to one composition (χ₂ = 0.33). A decrease of 40 °C in the melting temperature has been observed between the eutectic mixture and the pure compounds. We have isolated a co-crystal of (tBuN)₂MoCl₂·dme (dme = 1,2-dimethoxyethane) (3) and 2, also in a two to one ratio, which serves as a structural model for such mixtures. The lower melting point of carefully chosen eutectic mixtures can offer more consistent precursor delivery in deposition processes.