Chengfu Pi

1,2,4-Diazaphospholide complexes of samarium(III).

A series of 1,2,4-diazaphospholide (dp(-)) samarium complexes with a variety of coordination modes were prepared via the metathesis reaction of SmCl3(THF)3 and potassium 3,5-disubstituted 1,2,4-diazaphospholide or by the reaction of Sm[N(SiMe3)2]3 and 3,5-diphenyl-1,2,4-diazaphosphole.

A New Strategy for Ring Modification of Metallocenes: Carbodiimide Insertion into the η5-Y−C5H5 Bond and Subsequent Isomerization

Unusual insertion of carbodiimide into the Y-Cp (Cp = C(5)H(5)) bond and isomerization of the resulting cyclopentadienyl (Cp)-substituted amidinate complex to the amidino-substituted Cp complex have been established, representing an efficient and simple method for ring modification of sensitive metallocenes. All products, including the rare four-center interaction precursor of the insertion, have been characterized by X-ray structural analyses.

Structural diversity of 1,2,4-diazaphospholide complexes with alkali metals

Treatment of H[3,5-Ph2dp] (Hdp = 1H-1,2,4-diazaphosphole) with nBuLi or KH, or the reaction of K[3,5-tBu2dp] with an excess amount of O2, afforded the dimeric species [(eta2,eta1-3,5-Ph2dp)Li(THF)2]2 and the polymeric complexes [(eta2:eta4-3,5-Ph2dp)K(Et2O2]n, and [[(eta2:eta5-3,5-tBu2dp)K(THF)][eta2(N,N)-eta3(O,P,O)-3,5-tBu2dp-(O,O)O2K]]n, respectively.

1,2,4-Diazaphospholide Complexes of Barium: Mechanism of Formation and Crystallographic Characterization†

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.

1,2,4-Diazaphospholide Complexes of Tin(II): From Nitride Stannylene to Stannylenated Ammonium Ions

Tin knows its oniums! An unusual nitride tetrastannylene and a stannylenated ammonium ion stabilized by a samarium tetradiazaphospholido counterion are the first examples of a tris(organostannylenyl)amine derivative and a divalent tin coordinate onium ion that incorporates 1,2,4-diazaphospholide ligand (see figure).

Synthesis and structural characterization of lanthanide complexes with the di- or tri-anionic diguanidinate ligand: new insight into the flexibility and distinct reactivity of the linked diguanidinate ligand

Unprecedented disproportionation and deprotonation of the linked diguanidinate ligand have been established, demonstrating, for the first time, that the number and distribution of negative charges on the diguanidinate ligand are tunable, and representing a new and efficient method for synthesis of linked diguanidinate di- and tri-anion complexes.