Crystallographic characterisation of dihalogenodimethylselenium compounds, Me2SeX2 (X = Cl, Br or I) and the dependence of their structures on the nature of the halogen

Hypervalent Adducts of Chalcogen-Containing peri-Substituted Naphthalenes; Reactions of Sulfur, Selenium, and Tellurium with Dihalogens

“…14,15,22,47,49,50 The donor compounds 1,8-bis(phenylselenyl)naphthalene D2 and 1-(phenylselenyl)-8-(phenylsulfanyl)naphthalene D3 react with dibromine to form similar tribromide salts of analogous bromoselenyl cations which can be represented by the formula [RSe-Br] + ···[Br-Br 2 ] -(Scheme 1). 15 The lower electronegativity and hence greater electron donor ability of selenium over sulfur allows for a strong donor-strong acceptor system to form with dibromine sufficient to cleave the Br-Br bond and oxidise the selenium atom.…”

Telluranes: potential synthons for charge-transfer complexes (involving hypervalent Te–I bonds) and serendipitous synthesis of the first triphenyl methyl phosphonium salts containing [C4H8TeI4]2− and [TeI6]2−anions

“…Two distinct structural motifs are possible: R 2 YX 2 could be a charge transfer (CT) complex R 2 Y-X-X or it may correspond to W trigonal bipyramidal (TBP) structure. For example Me 2 SBr 2 is a CT complex Me 2 S-Br-Br [2] while Me 2 SeBr 2 [3] and Me 2 TeBr 2 [4] adopt WTBP structure. Me 2 SI 2 [1], Me 2 SeI 2 [3] are CT complexes and Me 2 TeI 2 [5,6] corresponds to WTBP structure.…”

Synthesis and Characterization of Ph4Te4I4, Containing a Te4 Square, and Ph3PTe(Ph)I

“…This compound is quite different from Ph 2 Se 2 I 2 and illustrates the sensitivity of the structure of such systems on the Group 15 or 16 atom, a phenomenon previously described by other workers and us. [1,7,9] Figure 2. The X-ray crystal structure of 1.…”

“…Both structures contain divalent tellurium atoms bonded to a phenyl group, a thiourea molecule, and, in trans position to the latter, a halogen atom. In common with 2, the Te À X bonds are rather long in these structures (TeÀCl 3.00(15), TeÀBr 3.11 (1) H} NMR spectrum of 2 reveals a single peak at d 26.9, which is shifted to higher field than that exhibited by Ph 3 PI 2 (d 44.2), which is known to ionize in CDCl 3 to produce [Ph 3 PI]I. This result suggests that 2 may retain its molecular CT structure in solution, however, no 125 Te satellites were observed.…”

“…For example, the dihalogen adducts of organoselenium compounds [1,2] and selenoamides [3±5] have all been intensively studied by a variety of research groups in the last few years. In addition, we have recently reported the structure of Ph 3 PSe-(Ph)I, formed from the reaction of Ph 3 P with Ph 2 Se 2 I 2 .…”