Bromination and iodination of diphosphane dichalcogenides

Abstract

The diphosphane dichalcogenides dppmSe, dppeSe, dprpmSe, dprpeSe, dppmS and dppeS, [dppm = bis(diphenylphosphano)methane, dppe = bis(diphenylphosphano)ethane, dprpm = bis(diisopropylphosphano)methane, dprpe = bis(diisopropylphosphano)ethane] have been treated with elemental bromine or iodine and the products 1-15 characterized by single crystal X-ray diffraction. DppeSe with bromine or iodine gives the simple (and previously known) adducts dppe(SeBr)1 or dppe(SeI)2 respectively; dprpeSe reacts similarly to give dprpe(SeBr)3 (at 0 °C) or dprpe(SeI)4. The bromine derivatives display a T-shaped geometry at selenium, whereas the iodine derivatives involve linear Se-I-I groups. With dppmSe and bromine, a product was formed at -50 °C, but could not be isolated; at room temperature the reaction leads to a mixture of products, from which only [dppmBr] [SeBr]5 (the anion involving a dibromine molecule coordinating to a Se centre) could be isolated. Reaction of dppeSe with excess bromine at room temperature leads to [dppeBr]·½[SeBr]·[SeBr·Br·Br]6. The reaction of dppmSe with iodine gives the 1 : 2 adduct [dppmSeI] [I]7, the cation of which contains a novel five-membered CPSe heterocycle. In a 1 : 1 ratio the same reaction gives another 1 : 2 adduct, [ISe(dppm)Se-I-Se(dppm)SeI] [I]8. DprpmSe with iodine gives [dprpmSeI] [I]9, analogous to 7, and with bromine at 0 °C the corresponding product [dprpmSeBr] [Br]10. At room temperature, dprpeSe reacts with bromine to give a mixture of [dprpe(SeBr)Br] Br11 and [dprpeBr] [SeBr]12, whereas dprpmSe forms [dprpmBr] [SeBr]13, analogous to 12. The disulfides dppmS and dppeS react with bromine to give [dppmSBr] [Br]14 and [dppeSBr] [Br]15.

Crystal structures of sixteen phosphane chalcogenide complexes of gold(I) chloride, bromide and iodide

“…diphosphane monochalcogenides; Taouss & Jones, 2013), as adducts with dihalogens (e.g. dppmSe 2 •2I 2 ; Upmann & Jones, 2018), or as ligands (e.g. an unusual coordination polymer of dppmS 2 with gold(I); Taouss et al, 2020).…”

Bringing Green Organic Electrochemistry to Undergraduates: A Designed Comparison Organic Experiment of Bromination

“…Traditional approaches of bromination of aromatic compounds could be broadly divided into two categories. One is using liquid bromine (Br 2 ) as bromine source under certain conditions; , the other is utilizing bromo-organic compounds, such as N -bromosuccinimide (NBS), 1,3-dibromo-5,5-dimethylhain (DBH), carbon tetrabromide, etc. , Several traditional synthetic schemes of bromination using NBS or liquid bromine are listed in Scheme b …”

Phosphanchalkogenide und ihre Metallkomplexe. V. Derivate von [2.2]Paracyclophanylphosphanena

“…Die wenigen Kristallen, die dabei isoliert werden konnten, bestanden aus (tht)AuBr 3 und dem selenfreien Produkt {(PCP)PPh [12]. Bei der Bromierung von Diphosphanchalkogeniden haben wir auch beobachtet, dass unter Verlust vom Chalkogen eine P-Br-Bindung geknüpft wird [13].…”

“…Durch die Reaktionen zwischen 8 und 9 mit (tht)AuCl oder (tht)AuBr konnten alle vier Gold(i)-Komplexe (PCP) i Pr 2 PEAuX isoliert werden [E = S, X = Cl (10), Br (11); E = Se, X = Cl (12), Br (13)]. Die Bromide waren allerdings instabil, so dass die entsprechenden Ausbeuten enttäuschend waren.…”