Synthesis and Structure of a Stable 1,3-Dihydrotriphosphane and Its Thermal Decomposition Leading to the Formation of the Corresponding Phosphine and Diphosphene

Abstract

Treatment of dichloroferrocenylphosphine with two molar amounts of a lithium phosphide bearing a 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (denoted as Tbt) group afforded the corresponding 1,3-dihydro-2-ferrocenyltriphosphane [1; (TbtHP) 2 PFc, Fc ) ferrocenyl] as a mixture of three diastereomers in 73% yield. In sharp contrast to the previously reported 1,3-dihydrotriphosphanes [(RHP) 2 PR, R ) Ph, t-Bu], 1 was quite stable toward air and moisture either in the solid state or in solution at ambient temperature. The structural characterization of 1 was achieved by NMR spectra and X-ray crystallographic analysis. In the 31 P{ 1 H} NMR spectrum of the mixture of three diastereomers of 1, the characteristic two A 2 B and one ABX system were observed as signals assignable to two meso and one dl isomer, respectively. The X-ray crystallographic analysis for a single crystal obtained from the diastereomer mixture of 1 revealed its molecular structure, having P-P bond lengths of 2.2304(12) and 2.2322(12) Å and a P-P-P bond angle of 96.17(5)°, although the configuration could not be determined. Thermolysis of 1 in toluene led to the quantitative formation of TbtPH 2 (2) and (E)-TbtPdPFc (3), as judged by the 1 H and 31 P NMR spectra. Kinetic studies indicated that the thermolysis of 1 is a first-order reaction including a unimolecular dissociative process, which was reasonablely supported by theoretical calculations.

Stepwise Expansion of a Cp* Ring at Pentelidene Complexes and Stereoselective Formation of Triphosphines

“…[13] Only 1,3-dihydrotriphosphines of the type (RPH) 2 PR' with bulky substituents (R = 2,4,6-[(Me 3 Si) 2 CH] 3 C 6 H 2 , R ' = (C 5 H 4 )CpFe (Cp = C 5 H 5 ), [14] and R = R' = tBu [15] ) are stable at room temperature, usually forming mixtures of three diastereomers. Significantly, the isolated triphosphine 5 shows only the A 2 M spin system of one diastereomer in the 31 P NMR spectrum, whereas for the arsadiphosphine 6 an A 2 and an AM spin system of a 1:1 mixture of two diastereomers have been found.…”

Chalcogenation reactions of a stable ferrocenyldiphosphene: Formation of thia‐, selena‐, and telluradiphosphiranes

“…Although Niecke et al reported the synthesis of Mes * P PFc, it was unstable and difficult to treat under ambient conditions due to its ready self-dimerization [33]. By contrast, we have reported the synthesis and isolation of TbtP PFc (1a), which was found to be thermally and photochemically stable without any dimerization, and its crystalline structure and redox behavior have been disclosed [10,11]. The first stable ferrocenyldiphosphene can be a useful building block for ferrocenyl-substituted heterocycles, such as chalcogenadiphosphiranes.…”

Synthesis and properties of group 9 metal complexes bearing a β-ketophosphenato ligand

“…Elemental analyses were carried out at the Microanalytical Laboratory of the Institute for Chemical Research, Kyoto University. TbtPH 2 [19] and b-enaminoketone 5 [16] were prepared according to the reported procedures.…”