Thermal Stability and Decomposition Pathways in VolatileMolybdenum(VI) Bis-imides

The vapor deposition of many molybdenum-containingfilms relieson the delivery of volatile compounds with the general bis(tert-butylimido)-molybdenum(VI) framework, both in atomic layer deposition and chemical vapordeposition. We have prepared a series of (tBuN)2MoCl2adducts using neutralN,N '-chelates and investigated their volatility, thermal stability, and decompositionpathways. Volatility has been determined by thermogravimetric analysis, with the1,4-di-tert-butyl-1,3-diazabutadiene adduct (5) found to be the most volatile (1Torr of vapor pressure at 135 degrees C). Thermal stability was measured primarily usingdifferential scanning calorimetry, and the 1,10-phenanthroline adduct (4) wasfound to be the most stable with an onset of decomposition of 303 degrees C. We havealso investigated molybdenum compounds with other alkyl-substituted imido groups: these compounds all follow a similardecomposition pathway,gamma-H activation, with varying reaction barriers. Thetert-pentyl, 1-adamantyl, and a cyclic imido (from 2,5-dimethylhexane-2,5-diamine) were systematically studied to probe the kinetics of this pathway. All of these compounds have beenfully characterized, including via single-crystal X-ray diffraction, and a total of 19 new structures are reported.

Automated summary

This study prepared a series of adducts of molybdenum compounds and investigated their volatility, thermal stability, and decomposition pathways. The properties were determined using thermogravimetric analysis and differential scanning calorimetry, and the structures were characterized using single-crystal X-ray diffraction.