title: The effect of the spacer of bis(biurea) ligands on the structure of A2 L3 -type (A=anion) phosphate complexes.
abstract: By tuning the length and rigidity of the spacer of bis(biurea) ligands L, three structural motifs of the A2 L3 complexes (A represents anion, here orthophosphate PO4 (3-) ), namely helicate, mesocate, and mono-bridged motif, have been assembled by coordination of the ligand to phosphate anion. Crystal structure analysis indicated that in the three complexes, each of the phosphate ions is coordinated by twelve hydrogen bonds from six surrounding urea groups. The anion coordination properties in solution have also been studied. The results further demonstrate the coordination behavior of phosphate ion, which shows strong tendency for coordination saturation and geometrical preference, thus allowing for the assembly of novel anion coordination-based structures as in transition-metal complexes.
authors.affiliation: Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069 (P. R. China). wubiao@nwu.edu.cn.
authors.forename: Biao
authors.initials: B
authors.lastname: Wu
authors.forename: Shaoguang
authors.initials: S
authors.lastname: Li
authors.forename: Yibo
authors.initials: Y
authors.lastname: Lei
authors.forename: Huaiming
authors.initials: H
authors.lastname: Hu
authors.forename: Nader
authors.initials: N
authors.lastname: de Sousa Amadeu
authors.forename: Christoph
authors.initials: C
authors.lastname: Janiak
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Mathieson
authors.forename: De-Liang
authors.initials: DL
authors.lastname: Long
authors.forename: Leroy
authors.initials: L
authors.lastname: Cronin
authors.forename: Xiao-Juan
authors.initials: XJ
authors.lastname: Yang
keywords: anion coordination; helicates; mesocates; oligourea; phosphates