title: Zwitterionic 4-bromo-6-meth-oxy-2-{[tris-(hy-droxy-meth-yl)methyl]-iminiumyl-meth-yl}phenolate: crystal structure and Hirshfeld surface analysis.
abstract: In the solid state, the title compound, C12H16BrNO5 [systematic name: 4-bromo-2-((1E)-{[1,3-dihy-droxy-2-(hy-droxy-meth-yl)propan-2-yl]iminium-yl}meth-yl)-6-meth-oxy-benzen-1-olate], C12H16BrNO5, is found in the keto-amine tautomeric form, with an intra-molecular iminium-N-H⋯O(phenolate) hydrogen bond and an E conformation about the C=N bond. Both gauche (two) and anti relationships are found for the methyl-hydroxy groups. In the crystal, a supra-molecular layer in the bc plane is formed via hy-droxy-O-H⋯O(hy-droxy) and charge-assisted hy-droxy-O-H⋯O(phenolate) hydrogen-bonding inter-actions; various C-H⋯O inter-actions provide additional cohesion to the layers, which stack along the a axis with no directional inter-actions between them. A Hirshfeld surface analysis confirms the lack of specific inter-actions in the inter-layer region.
authors.affiliation: Research Centre for Crystalline Materials, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia.
authors.forename: See Mun
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Research Centre for Crystalline Materials, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia.
authors.forename: Kong Mun
authors.initials: KM
authors.lastname: Lo
authors.affiliation: Research Centre for Crystalline Materials, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia.
authors.forename: Sang Loon
authors.initials: SL
authors.lastname: Tan
authors.affiliation: Research Centre for Crystalline Materials, Faculty of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia.
authors.forename: Edward R T
authors.initials: ER
authors.lastname: Tiekink
keywords: Hirshfeld surface analysis; crystal structure; hydrogen bonding; zwitterion