Crystal structures of two polymorphs for <i>fac</i>-bromidotricarbonyl[4-(4-methoxyphenyl)-2-(pyridin-2-yl)thiazole-κ² <i>N</i>,<i>N</i>′]rhenium(I)

Crystallization of the title compound, <i>fac</i>-[ReBr(ppt-OMe)(CO)₃] (ppt-OMe = C₁₅H₁₂N₂OS), from CH₂Cl₂/<i>n</i>-pentane (1:5 <i>v</i>/<i>v</i>) at room temperature gave two polymorphs, which crystallize in monoclinic (<i>P</i>2₁/<i>c</i>; α form) and ortho-rhom-bic (<i>Pna</i>2₁; β form) space groups. The Re^I complex mol-ecules in either polymorph adopt a six-coordinate octa-hedral geometry with three <i>facially</i>-oriented carbonyl ligands, one bromido ligand, and two nitro-gen atoms from one chelating ligand ppt-OMe. In the crystal, both polymorph α and β form di-periodic sheet-like architectures supported by multiple hydrogen bonds. In polymorph α, two types of hydrogen bonds (C-H⋯O) are found while, in polymorph β, four types of hydrogen bonds (C-H⋯O and C-H⋯Br) exist.