Synthesis and characterisation of four- and six-membered P–Se heterocycles

Abstract

The preparation, spectroscopic characterisation and crystal structures of [FcP(mu-Se)Se]2, [FcP(mu-Se2)Se]2 and [PhP(mu-Se2)Se]2 are reported. Crystallographic data reveal planar four-membered PSePSe and skewed six-membered P2Se4 rings, respectively, in all cases with trans arrangement of organic substituents and exo selenium atoms. Whilst stable at room temperature in solid state, NMR data suggest the six-membered rings of both the ferrocenyl and phenyl compounds decompose in the solution with loss of red selenium, forming PSe2PSe five-membered rings.

Application of four-membered ring chalcogenation reagents to the synthesis of new phosphorus-chalcogen heterocycles

“…In the newly formed ring the central phosphorus atom lies 0.195 Å in 1, 0.349 Å in 2 and 0.332 Å in 3 out of the P-S-S-C n (n = 2, 3) mean plane. The P=S double bond lengths in the structures of 1-3 are 1.934(2) Å, 1.9390(10) Å and 1.9351(7) Å, respectively, cf dithiophosphono disulfides [1.9203(14) -1.9303(7) Å], [29][30][31] are slightly shorter than that in other terminal phosphine sulphide bond lengths in the Cambridge Crystallographic Database (average 1.965 Å). The reaction of WR and alkyl-or aryl-dithiol was carried out under identical condition.…”

“…Analogous reactions were carried out by using FcLR 29,30 and dithiols. The reaction of FcLR with two molar equivalents of alkyl-or aryl-dithiols in refluxing toluene afforded five or seven-membered ring heterocycles 8-10 in good yields as shown in Scheme 2.…”

How Not to Discover a New Reagent. The Evolution and Chemistry of Woollins' Reagent

“…Leaning on our previous work in liquid ammonia we prepared Na 2 Se by simple reduction of selenium with sodium in liquid ammonia to give material which is We extended this preparative route to ferrocenyl systems and also obtained even more selenium rich heterocycles both directly and by conversion from WR (scheme 11). 46 Scheme 11 Formation of selenium rich P-Se heterocycles R = Ph, Fc.…”

An efficient, scalable synthesis of ferrocenylphosphine and dichloroferrocenylphosphine

“…12,13 The yields are low (11%) and repeated attempts to improve on this reaction demonstrated the yields to be highly variable and often much lower. 14,15 Nonetheless, this method was still being used relatively recently. 15,16 Scheme 1: Previous syntheses of FcPCl2.…”

“…14,15 Nonetheless, this method was still being used relatively recently. 15,16 Scheme 1: Previous syntheses of FcPCl2. [11][12][13] The most recent synthesis of ferrocenylphosphine, FcPH2, was reported by Wright and co-workers in 2009.…”