A high resolution powder X-ray diffraction study of the products of reaction of dimethyl sulfide with bromine; crystal and molecular structures of (CH3)2SBrn (n = 2, 2.5 or 4)

Abstract

The crystal and molecular structures of three reaction products formed between dimethyl sulfide and bromine have been characterised by high resolution powder synchrotron X-ray diffraction. Depending on the method of preparation, three compounds have been identified as (CH 3 ) 2 SBr 2 , (CH 3 ) 2 SBr 2.5 and (CH 3 ) 2 SBr 4 . The first, synthesised by the addition of bromine to dimethyl sulfide, was isolated as a single phase and is a charge-transfer adduct. The other two, both containing (CH 3 ) 2 SBr ϩ -like species, were found coprecipitated when dimethyl sulfide was added to bromine at Ϫ30 ЊC.

Self-assembly of supramolecular architectures based on polybromide anions: crystal structure of [tppz=tetra(2-pyridyl)pyrazine]

“…The FT-Raman spectrum of 2 is in agreement with the structural features of Br 2À 4 . In fact, a very intense peak at 167 cm À1 and a smaller one at about 74 cm À1 are present in the 50-500 cm À1 region, while no peak at about 230 cm À1 , reported for ðMe 2 SBrÞ þ ÞðBr À Þ 0:5 ðBr 2À 4 Þ 0:25 [11], and attributed to the Br-Br stretching, has been observed (Fig. 3).…”

“…Since the tendency of halides to catenate decreases dramatically on passing from iodine to bromine and chlorine, the variety of reported discrete polybromides is far less large than that of polyiodides. To the best of our knowledge, apart from Br À 3 , only Br 2À 4 (characterised in W 6 Br 16 [7], W 6 Br 18 [8], [(p-Br-C 6 H 4 -CH 2 )P(C 6 -H 5 ) 3 ]Br 2 [9], [(CH 3 ) 2 NH AE HBr] 2 Br 2 [10], and ðMe 2 SBrÞ þ ðBr À Þ 0:5 ðBr 2À 4 Þ 0:25 [11]) and Br 2À 8 (isolated in (quinoclidinium) 2 Br 8 [12]) have been reported so far. Nevertheless, the recent isolation of an infinite polybromide 2D-network in the crystal structure of [(1 AE 2Br) 2+ (Br À ) 2 (Br 2 ) 3 ] (1 = 4,5,9,10-tetrathiocino-[1,2-b:5,6-b 0 ]-1,3,6,8-tetraethyl-diimidazolyl-2,7-dithione) showed the ability of bromine also to give rise to interactions, whose nature and geometrical motifs are strictly similar to those found in the far more explored chemistry of polyiodides [13].…”

Recent Discoveries of Polyhalogen Anions – from Bromine to Fluorine

“…[Br 4 ] 2– is also found in the crystal structure of W 6 Br 16 which is built of [W 6 Br 8 ] 6+ cations and [Br 4 ] 2– anions 51. [(CH 3 ) 2 SBr] + [Br – 0.5 (Br 4 2– ) 0.25 ]52 and [H 4 tppz] 4+ [(Br – ) 2 (Br 4 2– )] [tppz = tetra(2‐pyridyl)pyrazine]53 were characterized by X‐ray methods and Raman spectroscopy. The structure [H 4 tppz] 4+ [(Br – ) 2 (Br 4 2– )] consists of [H 4 tppz] 4+ [(Br – ) 2 ] pillars, which are interconnected by [Br 4 ] 2– anions through weak Br–H contacts and form a three‐dimensional network.…”

Polyhalogen and Polyinterhalogen Anions from Fluorine to Iodine

“…More polybromine dianions than monoanions are experimentally known, currently eight:[ Br 4 ] 2À , [115][116][117] [Br 6 ] 2À , [118] [Br 8 ] 2À , [30,93,119] [Br 10 ] 2À , [120] [Br 14 ] 2À , [121] [Br 16 ] 2À , [121] [Br 20 ] 2À , [29,33,121] and [Br 24 ] 2À . [34] Thet ypically observed and calculated Raman bands are listed in Table 10.…”