Synthesis and Large Crystal Growth of a Noncentrosymmetric Sodium Methylsulfanetriol Borate Lewis-Adduct: Na(S(OH)₃CH₃)(BO₃)

A new metal methanesulfonate-derived borate compound, Na(S(OH)₃CH₃)(BO₃) (NMSB), was successfully synthesized. NMSB crystallizes in the cubic and acentric space group <i>P</i>2₁3 (no. 198) and may be grown as large, high-quality millimeter to centimeter-sized crystals through spontaneous crystallization under ambient conditions [<i>a</i> = 8.7714(2) Å, <i>Z</i> = 4]. NMSB exhibits a three-dimensional structure composed of a new methylsulfanetriol functional group, [S(OH)₃CH₃]²⁺, and extended H-bonding with planar [BO₃]^3- groups. The framework is formed by the Lewis acid-base reaction of SO: → HOB, structurally and charge-balanced by distorted NaO₆ octahedra. The composition, structure, and facet-indices are confirmed by SC-XRD, PXRD, EDS, and FT-IR spectroscopy. UV-vis diffuse reflectance spectroscopy shows that NMSB is transparent in the UV-vis region with an optical absorption edge in the deep-UV region, λ_abs < 200 nm. NMSB is thermally stable up to 200 °C and is highly soluble in water. This new compound exhibits unique borate chemistry as well as insights into underexplored methanesulfonate-derived salts as optical materials.