title: Crystal structure of trans-N,N'-bis-(3,5-di-tert-butyl-2-hy-droxy-phen-yl)oxamide methanol monosolvate.
abstract: The here crystallized oxamide was previously characterized as an unsolvated species [Jímenez-Pérez et al. (2000 ▸). J. Organomet. Chem. 614-615, 283-293], and is now reported with methanol as a solvent of crystallization, C30H44N2O4·CH3OH, in a different space group. The introduction of the solvent influences neither the mol-ecular symmetry of the oxamide, which remains centrosymmetric, nor the mol-ecular conformation. However, the unsolvated mol-ecule crystallized as an ordered system, while many parts of the solvated crystal are disordered. The hy-droxy group in the oxamide is disordered over two chemically equivalent positions, with occupancies 0.696 (4):0.304 (4); one tert-butyl group is disordered by rotation about the C-C bond, and was modelled with three sites for each methyl group, each one with occupancy 1/3. Finally, the methanol solvent, which lies on a twofold axis, is disordered by symmetry. The disorder affecting hy-droxy groups and the solvent of crystallization allows the formation of numerous supra-molecular motifs using four hydrogen bonds, with N-H and O-H groups as donors and the oxamide and methanol mol-ecule as acceptors.
authors.affiliation: Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, 72570 Puebla, Pue., Mexico.
authors.forename: Miguel-Ángel
authors.initials: MÁ
authors.lastname: Velázquez-Carmona
authors.affiliation: Instituto de Física, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y 18 Sur, 72570 Puebla, Pue., Mexico.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Bernès
authors.affiliation: Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, 72570 Puebla, Pue., Mexico.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Ríos-Merino
authors.affiliation: Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, 72570 Puebla, Pue., Mexico.
authors.forename: Yasmi
authors.initials: Y
authors.lastname: Reyes Ortega
keywords: crystal structure; disorder; hydrogen bonding; oxamide; solvate