title: 1,2,4-Diazaphospholide complexes of barium: mechanism of formation and crystallographic characterization.
abstract: A number of barium 1,2,4-diazaphospholide (dp(-)) complexes have been prepared by protonolysis of barium bis[bis(trimethylsilyl)]amide (Ba[N(SiMe(3))(2)](2)(THF)(2)) and the corresponding 1,2,4-diazaphospholes. The bis(3,5-diphenyl-1,2,4-diazaphospholide)-tetrakis(tetrahydrofuran)barium [eta(2)(N,N)-3,5-Ph(2)dp)(2)Ba(THF)(4)] (1) and bis(3,5-diphenyl-1,2,4-diazaphospholide)-tetrakis(dimethylsulfoxide)barium [eta(2)(N,N)-3,5-Ph(2)dp)(2)Ba(DMSO)(4)] (2) were prepared by the reactions of Ba[N(SiMe(3))(2)](2)(THF)(2) and 3,5-diphenyl-1,2,4-diazaphosphole (H[3,5-Ph(2)dp]) in tetrahydrofuran (THF) or dimethylsulfoxide (DMSO), respectively, while the bis(3,5-disubstituted-1,2,4-diazaphospholide)-(18-crown-6) barium complexes [trans-eta(2)(N,N)-dp)(2)Ba(18-crown-6)] (3), [cis-eta(2)(N,N)-tBu(2)dp)(2)Ba(18-crown-6)] (4), [trans-eta(2)(N,N)-tBu(2)dp)(2)Ba(18-crown-6)] (5), [cis-eta(2)(N,N)-Ph(2)dp)(2)Ba(18-crown-6)] (6), and [trans-eta(2)(N,N)-Ph(2)dp)(2)Ba(18-crown-6)] (7) were synthesized by the reaction of Ba[N(SiMe(3))(2)](2)(THF)(2) and the corresponding 1,2,4-diazaphospholes in the presence of 18-crown-6 in THF or DMSO. Complexes 1, 2, 3, 4, and 7 have been structurally characterized. Complex 4 is the first structurally characterized barium complex in which the two organic ligands are located on the same side of 18-crown-6 (cis conformation). The (31)P{(1)H} NMR spectra suggested a partial dissociation of the barium 1,2,4-diazaphospholides 2, 4, and 7 into the corresponding ion associated complexes in solutions.
authors.affiliation: Department of Chemistry, Fudan University, Handan Road 220, Shanghai 200433, China.
authors.forename: Chengfu
authors.initials: C
authors.lastname: Pi
authors.forename: Li
authors.initials: L
authors.lastname: Wan
authors.forename: Weiping
authors.initials: W
authors.lastname: Liu
authors.forename: Zaifu
authors.initials: Z
authors.lastname: Pan
authors.forename: Haoyu
authors.initials: H
authors.lastname: Wu
authors.forename: Yunhua
authors.initials: Y
authors.lastname: Wang
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zheng
authors.forename: Linhong
authors.initials: L
authors.lastname: Weng
authors.forename: Zhenxia
authors.initials: Z
authors.lastname: Chen
authors.forename: Limin
authors.initials: L
authors.lastname: Wu
mesh_terms: D001464:Barium / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D009944:Organoplatinum Compounds / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D009944:Organoplatinum Compounds; D001464:Barium