5-Benzyl­idene-2,3-diphenyl-1,2-selenaphosphole-2-selenide

The title compound, C23H19PSe2, has a central five-membered twist C3PSe ring conformation. One phenyl ring substituent, attached to an sp 2 carbon, is approximately coplanar with the C3PSe ring whilst the other organic substituents, attached to an sp 3-carbon and a PV atom, lie on the same side of the ring

Synthesis and single crystal structures of substituted-1,3-selenazol-2-amines

This article belongs to the Special Issue Celebrating Two Centuries of Research in Selenium Chemistry: State of the Art and New ProspectivesThe synthesis and X-ray single crystal structures of a series of new 4-substituted-1,3-selenazol-2-amines is reported. The efficient preparation of 4-substituted-1,3-selenazol-2-amines was carried out by two-component cyclization of the selenoureas with equi-molar amounts of α-haloketones. The selenoureas were obtained from the reaction of Woollins’ reagent with cyanamides, followed by hydrolysis with water. All new compounds have been characterized by IR spectroscopy, multi-NMR (1H, 13C, 77Se) spectroscopy, accurate mass measurement and single crystal X-ray structure analysis.Publisher PDFPeer reviewe

2,2′-o-Phenyl­enediacetonitrile

In the title compound, NCCH2C6H4CH2CN, the bond lengths and angles are within normal ranges. The benzene ring makes dihedral angles of 4.94 (8) and 77.04 (8)° with the C—C—C—N mean planes. Weak non-conventional C—H⋯N hydrogen bonds are effective in the stabilization of the crystal structure. The weak C—H⋯N contacts form anti­parallel chains running in the a + c direction, and ring systems with two N-atom acceptors and four H-atom donors

Bis(phenyl­phospho­nic) anhydride

The asymmetric unit of the title compound, C12H12O5P2, contains four independent mol­ecules, generating two dimers via pairs of inter­molecular O—H⋯O hydrogen bonds, forming R 2 2(8) rings. The two aryl rings of each mol­ecule form dihedral angles of 108.6 (1), 103.2 (1), 12.5 (2) and 8.1 (2)° in the four mol­ecules

Synthesis and structural study of novel selenation derivatives of N, N-Dialkylcyanamides

We are grateful to the University of St Andrews for financial support and the EPSRC National Mass Spectrometry Service Centre (Swansea) for mass spectral measurements.The reaction of 2,4-bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide {[PhP(Se)(µ-Se)]2, Woollins’ reagent, WR } with N, N-dialkylcyanamides 1–3 in refluxing toluene solution led to the corresponding [2+3] cycloaddition products 4-dialkylamino-2,5-diphenyl-1,3,2,5-selenazadiphosphole 2,5-diselenides 4–6 in good yields, the latter were further treated with water resulting in the corresponding hydrolysis derivatives dialkyl-selenoureas 7–9 , and phosphinodiselenoates 10 and 11 . Selenourea 7 could be transferred into 1,3-selenazol-2-amines 12–15 in excellent yields by further cyclization with four different α-haloketones. All new compounds have been characterized by IR spectroscopy, multi-NMR (1H, 13C, 31P, 77Se) spectroscopy and accurate mass measurement. The single crystal X-ray structural features of nine new compounds are also discussed.PostprintPostprintPeer reviewe

1,5,6-Triphenyl-8-oxa-7-selena-6-phos­phabicyclo­[3.2.1]octane-6-selone

The structure of the title compound, C23H21OPSe2, consists of fused puckered five- and six-membered rings, PSeC2O and C5O, respectively, with a C2O bridgehead. The C5O ring adopts a chair conformation, whilst the C2PSeO ring has an envelope conformation

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

The authors are grateful to the University of St Andrews for financial support.The reaction of four-membered ring chalcogenation reagents such as Lawesson’s reagent, 2,4-diferrocenyl-1,3,2,4-diathiadiphosphetane 2,4-disulfide (the ferrocene analogy of Lawesson’s reagent) and Woollins’ reagent with alkyl- or aryl-dithiols in refluxing toluene gave a series of five- to seven-membered organo-phosphorus-chalcogen heterocycles in 24% to 87% yields. Five representative X-ray structures confirm the formation of these five- to seven-membered heterocycles.Publisher PDFPeer reviewe

Organo phosphorus-sulfur-nitrogen heterocycles from thionation of Schiff bases

Funding: University of St Andrews.A series of heteroatom derivatives were prepared from the reactions of amido-Schiff bases as well as simpler imine with 2,4-diferrocenyl-1,3,2,4-diathiadiphosphetane 2,4-disulfide ( FcLR ). Six related structures have been characterized by single crystal X-ray diffraction.Publisher PDFPeer reviewe

Novel five- and six-membered ring phosphorus-selenium heterocycles from selenation of amido-Schiff bases

Authors are grateful to the University of St Andrews for financial support.Woollins’ reagent, [2,4-bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide], serving as a selenating-reductive cycloaddition reagent, reacts with nonconjugated amido-Schiff bases to give the corresponding six-membered 1,3,4-selenadiazoles via a ring-expansion accompanied by an additional selenation/cyclization to the imine bond and C═O group; meanwhile, under the same reaction conditions, the selenation of conjugated amido-Schiff bases leads to a series of fused heterocycles with two five-membered rings. Eight single-crystal X-ray structures confirming the formation of these five- and six-membered heterocycles are discussed.Publisher PDFPeer reviewe