Mo. Rev. Stat. § 144.817
In addition to the exemptions granted pursuant to the provisions of section 144.030, there shall also be specifically exempted from the provisions of the local sales tax law as defined in section 32.085, section 238.235, and sections 144.010 to 144.525 and 144.600 to 144.745, and from the computation of the tax levied, assessed, or payable pursuant to the local sales tax law as defined in section 32.085, section 238.235, and sections 144.010 to 144.525 and 144.600 to 144.761, purchases of any item of tangible personal property which is, within one year of such purchase, donated without charge to the state of Missouri. The exemption prescribed in this section includes purchases of all items of tangible personal property converted into an item donated as a gift to the state of Missouri.
§ 144.817, RSMo