Synthetic, Structural and Vibrational Spectroscopic Studies in Bismuth(III) Halide/N,N′-Aromatic Bidentate Base Systems. II Bipyridinium (2,2' Bipyridine) tetraholobismuthate (III) (Halogen = Chloride or Bromide)

1998 ◽  
Vol 51 (4) ◽  
pp. 311 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Jack M. Harrowfield ◽  
Aaron M. Lee ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Single Crystal ◽  
Raman Spectra ◽  
Room Temperature ◽  
Far Infrared ◽  
Spectroscopic Studies ◽  
Infrared And Raman Spectra ◽  
X Ray ◽  
Structure Determinations ◽  
Anionic Species

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for the title compounds, [bpyH]+[(bpy)BiX4]-, X = Cl, Br, the chloride being obtained in a second acetonitrile- sesquisolvated form. [bpyH]+[(bpy)BiX4]-, X = Cl, Br, are isomorphous, monoclinic C2/c, a ≈ 15·3, b ≈ 9·6, c ≈ 16·8 Å, β 109°, Z = 4, conventional R on |F| being 0·056, 0·059 for No 1456, 769 independent ‘observed’ (I > 3σ(I)) reflections respectively. [bpyH] [(bpy)BiCl4].1½MeCN is monoclinic, P21/m, a 9·572(2), b 34·521(8) c 8·218(2) Å, β 102·13(2)°, Z = 4, R 0·043 for No 2635. All anionic species are mononuclear, the bismuth being quasi-octahedral. Bands in the far-infrared and Raman spectra due to the vibrations of the N2BiCl4 core in [(bpy)BiCl4]- are assigned, and their relationship to the vibrations of [BiCl6]3- is discussed.

Synthetic, Structural and Vibrational Spectroscopic Studies in Bismuth(III) Halide/N,N ′-Aromatic Bidentate Base Systems. III Some Novel Bismuth(III) Halide/N,N ′-Bidentate Ligand (1 : 1)

1998 ◽  
Vol 51 (4) ◽  
pp. 317 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Peter C. Junk ◽  
Aaron M. Lee ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Room Temperature ◽  
Far Infrared ◽  
Spectroscopic Studies ◽  
Bidentate Ligand ◽  
Mononuclear Complex ◽  
Infrared And Raman Spectra ◽  
Dmso Solution ◽  
Coordination Environment ◽  
X Ray ◽  
Structure Determinations

Syntheses and single-crystal room-temperature X-ray structure determinations are recorded for a number of adducts obtained by the crystallization of bismuth(III) halides with 2,2′-bipyridine (bpy) or 1,10- phenanthroline (phen) from dimethyl sulfoxide (dmso) solution. [(phen)BiX3(O-dmso)2].dmso, X = Cl, Br, are triclinic, P-1,a ≈ 14·6, b ≈ 9·7, c ≈ 9·5 Å, α ≈ 96, β ≈ 96, γ ≈ 98°, Z = 2; conventional R on | F| were 0·057, 0·037 for No 5775, 4847 independent ‘observed’ (I > 3σ(I)) reflections respectively. The metal atom coordination environments are seven-coordinate pentagonal bipyramidal with axial halides and the two O-dmso ligands cis in the equatorial plane. BiI3/phen/dmso (1 : 1 : 1 ) is orthorhombic, Pmc21, a 12·745(3), b 9·697(3), c 18·335(5) Å, Z = 4, R 0·049 for No 2012. The complex is ionic [(phen)BiI2(O-dmso)3]+[(phen)BiI4]-, the halide atoms being axial in a pentagonal bipyramidal array about the metal in the cation, with a quasi-octahedral coordination environment in the anion. With bpy, by contrast, BiI3/bpy/dmso (1 : 1 : 1) is obtained, orthorhombic, Pnma, a 17·86(2), b 12·87(1), c 8·47(1) Å, Z = 4, R 0·058 for No 1194, a neutral mononuclear complex [(bpy)BiI3(O-dmso)] with a six-coordinate array about the metal, O-dmso trans to an iodine atom. Bands in the far-infrared and Raman spectra due to the vibrations of the O2N2BiX3 cores in [(phen)BiX3(O-dmso)2] (X = Cl, Br) are assigned, and discussed in relation to the structures of the complexes.

Syntheses, Structures and Vibrational Spectra of Some Dimethyl Sulfoxide Solvates of Bismuth(III) Bromide and Iodide

1998 ◽  
Vol 51 (4) ◽  
pp. 285 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Jack M. Harrowfield ◽  
Peter C. Junk ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Single Crystal ◽  
Dimethyl Sulfoxide ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Room Temperature ◽  
Far Infrared ◽  
Infrared And Raman Spectra ◽  
X Ray

Room-temperature single-crystal X-ray studies are recorded for some dimethyl sulfoxide (dmso) solvates of bismuth(III) bromide and iodide. Colourless BiBr3.3dmso is triclinic, P-1, a 8·467(4), b 9·109(4), c 13·901(4) Å, α 76·34(4), β 76·95(4), γ 64·56(4)°, Z = 2; conventional R on |F| was 0·050 for No 2306 independent ‘observed’ (I > 3σ(I)) reflections. The complex is mononuclear with a quasi-octahedral fac-bismuth environment, [(dmso-O)3BiBr3], isomorphous with the previously determined chloride. Orange BiI3-2dmso is triclinic, P-1, a 12·558(2), b 8·962(2), c 8·342(1) Å, α 61·85(1), β 78·27(1), γ 76·89(2)°, Z = 2 f.u., R 0·048 for No 1953. The complex is binuclear, a pair of iodide atoms bridging the two bismuth atoms, [(dmso-O)2I2Bi(µ-I)2BiI2(O-dmso)2]; the two O-dmso ligands about each six-coordinate bismuth lie trans. Red BiI3.2 ⅔ dmso is triclinic, P-1, a 16·435(6), b 14·926(2), c 12·396(3) Å, α 74·89(2), β 73·24(2), γ 79·18(2)°, Z = 6, R 0·059 for No 5858. The complex is [Bi(O-dmso)8] [Bi2I9], the eight-coordinate metal environment of the cation being, unusually, dodecahedral; in the anion a pair of quasi-octahedral six-coordinate bismuth atoms are bridged by three iodides, [I3Bi(µ-I)3BiI3]3-. Bands in the far-infrared and Raman spectra due to the v(BiX) modes are assigned and discussed in relation to the structures of the complexes. The assignment of the v(BiO) modes is discussed.

Synthetic, Structural and Vibrational Spectroscopic Studies in Bismuth(III) Halide/N,N′-Aromatic Bidentate Base Systems. V Bismuth(III) Halide/N,N′-Bidentate Ligand (1 : 2) Systems

1998 ◽  
Vol 51 (4) ◽  
pp. 331 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Frances M. M. Hannaway ◽  
Peter C. Junk ◽  
Aaron M. Lee ◽  
Brian W. Skelton ◽  
...  
Keyword(s):  
Single Crystal ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Far Infrared ◽  
Spectroscopic Studies ◽  
Bidentate Ligand ◽  
X Ray ◽  
B 31 ◽  
Far Infrared Spectra

Syntheses and room-temperature single-crystal X-ray determinations are recorded for a number of adducts of BiX3/N,N′-bidentate 1 : 2 stoichiometry (N,N′-bidentate = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen)). BiX3/bpy (1 : 2), X = Br, I, are isomorphous, monoclinic, P21/c, a ≈ 7·5, b ≈ 31, c ≈ 10·3 Å, β ≈ 113°, Z = 4; conventional R on |F| were 0·058, 0·055 for No 1744, 2068 independent ‘observed’ (I > 3σ(I)) reflections. BiCl3/phen (1 : 2) is monoclinic, P21/C, a 9·675(3), b 31·845(7), c 7·756(2) Å, β 109·94(2), Z = 4, R 0·071 for No 2537, while BiBr3/phen (1 : 2), also monoclinic, P21/c, has a 17·590(5), b 8·812(2), c 17·537(7) Å, β 117·58(3)°, Z = 4; R 0·083 for No 890. BiX3/phen (1 : 2).S, X/S = Br/MeCN, I/CH2Cl2, are isomorphous, orthorhombic, Pna21, a ≈ 20·7, b ≈ 14·2, c ≈ 8·9 Å, Z = 4, R 0·060, 0·046 for No 1553, 2423 respectively. All complexes are mononuclear with seven-coordinate (N2)2BiX3 bismuth environments. Bands in the far-infrared spectra due to the v(BiX) vibrations in [(phen)2BiCl3] and [(bpy)2BiX3] (X = Br, I) are assigned and discussed in relation to the structures of the complexes.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXVI Synthesis, Spectroscopy and Structural Systematics of Some 1 : 3 Adducts of Copper(I) Compounds with Triphenylstibine, [(Ph3Sb)3CuX], X = Br, I, ONO2

1997 ◽  
Vol 50 (6) ◽  
pp. 567 ◽  
Author(s):  
Robert D. Hart ◽  
Graham A. Bowmaker ◽  
Allan H. White
Keyword(s):  
Single Crystal ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Far Infrared ◽  
Lewis Base ◽  
X Ray ◽  
Strong Band ◽  
C 23 ◽  
Structure Determinations ◽  
Far Infrared Spectra

The syntheses of adducts, [(Ph3Sb)3CuX], X = Br, I, NO3, obtained by crystallization of 1 : 3 CuX/SbPh3 mixtures from appropriate solvents are described, together with their room-temperature single-crystal X-ray structure determinations. The bromide, obtained as a chloroform monosolvate from that solvent, is triclinic, P-1, a 13·861(4), b 14·306(4), c 14·347(4) Å, α 84·40(2), β 86·93(2), γ 75·56(2)°, Z = 2 f.u., conventional R on F being 0·053 for No = 4136 independent ‘observed’ (I > 3σ(I)) reflections; this solvate is isomorphous with its previously recorded chloride counterpart. The iodide is triclinic, P-1, a 14·55(1), b 14·385(2), c 23·626(6) Å, α 91·78(1), β 90·77(4), γ 92·54(5)°; Z= 4, R 0·050 for No 6917, and isomorphous with its phosphorus counterpart. The nitrate, although a methanol sesquisolvate, is also isomorphous with the chloride and bromide, a 13·369(9), b 14·398(3), c 14· 504(12) Å, α 82·29(5), β 84·39(6), γ 75·11(4)°, R 0·052 for No 5672. Cu-X are (2·235(5) (Cl)), 2·366(3) (Br), 2· 556(2) ( 2 ) (I), 1·98(1) Å (ONO2), appreciably shorter than in their previously recorded EPh3, E = P, As counterparts. The far-infrared spectra of [(Ph3Sb)3CuX] showed no clear v(CuX) bands, in contrast to the situation reported previously for the corresponding Ph3P and Ph3As compounds. It is likely that v(CuCl) is masked by a strong band at 270 cm-1 due to the Ph3Sb ligand. However, the region below 250 cm-1 in which the v(CuX) bands are expected for the X = Br, I complexes contains no strong ligand bands. Possible reasons for the absence of v(CuX) bands in these complexes are considered.

Synthetic, Structural and Vibrational Spectroscopic Studies in Bismuth(III) Halide/N,N′-Aromatic Bidentate Base Systems. IV Bismuth(III) Halide/N,N′-Bidentate Ligand (1 : 1) Systems

1998 ◽  
Vol 51 (4) ◽  
pp. 325 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Frances M. M. Hannaway ◽  
Peter C. Junk ◽  
Aaron M. Lee ◽  
Brian W. Skelton ◽  
...  
Keyword(s):  
Single Crystal ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Far Infrared ◽  
Spectroscopic Studies ◽  
Bidentate Ligand ◽  
X Ray ◽  
Far Infrared Spectra

Room-temperature single-crystal X-ray studies are recorded for a number of adducts of BiX3 and N,N′-bidentate ligand (2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen)), devoid of coordinated solvent. BiBr3/bpy/MeCN (1 : 1 : 1) is triclinic P-1, a 12·129(2), b 9·955(4), c 7·748(1) Å, α 73·14(2), β 77·34(1), γ 69·79(2)°, Z = 2; conventional R on |F| was 0·036 for No 2252 independent ‘observed’ (I > 3σ(I)) reflections. The phen analogue is isomorphous, a 11·586(3), b 10·839(6), c 7·769(10) Å, α 73·70(7), β 76·67(7), γ 70·34(4)°, Z = 2, R 0·042 for No 800. BiI3/bpy (1 : 1) is triclinic, P-1, a 11·742(4), b 9·261(1), c 8·261(3) Å, α 86·46(2), β 71·48(3), γ 67·25(2)°, Z = 2, R 0·043 for No 1164. All complexes are centrosymmetric binuclear [(N,N′-bidentate)X2Bi(µ-X)2BiX2(N,N′-bidentate)] with six-coordinate pseudo-octahedral bismuth(III). Attempts to produce a chloride analogue have resulted, in the case of N,N′-bidentate = bpy, in a novel adduct of BiCl3/bpy 1 : 1·5 stoichiometry, monoclinic, P21/c, a 9·377(8), b 17·699(5), c 21·58(1) Å, β 107·82(6)°, Z = 8, R 0·055 for No 1804. The complex is [(bpy)2Cl2Bi(µ-Cl)BiCl3(bpy)], containing seven- and six-coordinate bismuth. Bands in the far-infrared spectra due to the v(BiX) vibrations in [(bpy)2Cl2Bi(µ-Cl)BiCl3(bpy)] and [(bpy)I2Bi(µ-I2)BiI2(bpy)] are assigned and discussed in relation to the structures of the complexes.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXIV Syntheses, Spectroscopy and Structures of Some 1 : 4 Adducts of Copper(I) and Silver(I) Perchlorates with Triphenylarsine and Triphenylstibine

1997 ◽  
Vol 50 (6) ◽  
pp. 539 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Effendy ◽  
Robert D. Hart ◽  
John D. Kildea ◽  
Brian W. Skelton ◽  
...  
Keyword(s):  
Room Temperature ◽  
Far Infrared ◽  
Lewis Base ◽  
X Ray ◽  
Cation Disorder ◽  
Structure Determinations ◽  
Consistent Picture ◽  
Far Infrared Spectra

Syntheses and room-temperature single crystal X-ray structure determinations are recorded for adducts [M(EPh3)4] (ClO4), M = Cu, E = As (1), Sb (2); M = Ag, E = As (3), Sb (4), enabling comparison with analogous, previously studied MP4 and MN4 environments. The four complexes so characterized all crystallize in the familiar rhombohedral R-3 array (a ≈ 14·4, c ≈ 52 Å, hexagonal setting) with the metal and chlorine atoms located on crystallographic threefold axes. In these arrays Cu–E (axial, off axis) are 2·493(2), 2·533(1) for (1), and 2·572(1), 2·577(1) Å for (2), the disparity in the two independent M-E distances being diminished relative to those of previously studied phosphorus analogues, perhaps in consequence of increasing E size. In (3) and (4), some cation disorder is evident in respect of the ligand pnictide atom (E); for the major components Ag-E are 2·652(3), 2·680(2) in (3); 2·732(2), 2·7295(8) Å in (4). Problems associated in defining the metal atom environment geometries in the latter are, nevertheless, more satisfactorily overcome in two further determinations of nitrate salts: [Ag(SbPh3)4] (NO3) (5) is of the rhombohedral family with no cation core disorder, Ag–E (axial, off axis) being 2·720(4), 2·725(2) Å, while the structural characterization of a 1 : 4 triphenylarsine adduct of silver nitrate is recorded as its tetraethanol solvate, namely [Ag(AsPh3)4] (NO3).~ 4C2H5OH(6), monoclinic, C2/c, a 18·373(4), b 20·786(5), c 21·070(8) Å, β 108·18(3)°, Z = 4 f.u. The silver atom of the [Ag(AsPh3)4]+cation unusually lies on a crystallographic 2 (rather than a 3 ) axis of the incipiently23 (T) array, with Ag-As 2·649(2), 2·650(2) Å and As-Ag-As ranging from 108·22(4) to 111·41(6)°. The structure determination of a chloroform solvate of (2), denoted (2a), of low precision, is noted, together with the structure of an interesting artefact, isomorphous with the rhombohedral oxoanion array, modelled as [Ag(PPh3)4]2 (SiF6).py (7). Bands in the far-infrared spectra of [M(AsPh3)4] (ClO4) are assigned to v(MAs) vibrations at 119 (M = Cu) and 103 cm¯1 (M = Ag); this produces a more consistent picture of the variation in the wavenumbers of the v(ME) modes in [M(EPh3)4]+ compounds than was available previously.

The Vibrational Spectra and Crystal Structure of Acenaphthylene

1973 ◽  
Vol 51 (3) ◽  
pp. 402-404 ◽  
Author(s):  
A. Bree ◽  
R. A. Kydd ◽  
V. V. B. Vilkos ◽  
R. S. Williams
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Room Temperature ◽  
Infrared And Raman Spectra ◽  
Depolarization Ratio ◽  
X Ray

A study of the polarized infrared and Raman spectra of acenaphthylene single crystals has been made. These results, together with Gordon and Yang's preliminary X-ray work, suggest that the molecules pack in some disordered arrangement in the solid at room temperature. Most of the A1 fundamentals were identified in the Raman solution spectrum from their low depolarization ratio, and a few tentative assignments of nontotally symmetric fundamentals were made.

Lewis-Base Adducts of Lead(II) Compounds. XVII. Synthetic and Structural Studies of Some 1:1 Adducts of 2,2':6,2'-Terpyridine With Lead(II) Salts

1996 ◽  
Vol 49 (10) ◽  
pp. 1135 ◽  
Author(s):  
LM Engelhardt ◽  
JM Harrowfield ◽  
H Miyamae ◽  
JM Patrick ◽  
BW Skelton ◽  
...  
Keyword(s):  
Water Molecule ◽  
Single Crystal ◽  
Room Temperature ◽  
Lewis Base ◽  
Polymeric Chain ◽  
Lead Atom ◽  
X Ray ◽  
Structure Determinations ◽  
Pass Through ◽  
Nitrate And Nitrite

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for 1:1 adducts of 2,2':6',2"-terpyridine (' tpy ') with the lead(II) oxoanion salts perchlorate, nitrate and nitrite, ( tpy ) Pb ( oxoanion )2. All structures are monoclinic, C2/c, Z = 4, with approximate ranges a from 9 to 11 Ǻ, b from 16 to 20 Ǻ, c from 9.8 to 13.8 Ǻ, β from 113 to 130° and V from 1650 to 1850 Ǻ3. In all cases the lead(II) atoms are disposed on crystallographic 2 axes which also pass through the axis of the central tpy ring; a pair of symmetry related oxoanions link successive lead atoms in a one-dimensional polymeric chain parallel to the ac cell diagonal, one pair of oxygen atoms functioning as an O,O'-bidentate with another oxygen (replaced by the nitrogen in the nitrite) bridging to the adjacent lead atom; the third anionic oxygen atom in the nitrate is replaced by a water molecule in the nitrite, which thus becomes a monohydrate. Residuals were 0.030, 0.034 and 0.040 for 2122, 1564 and 2059 independent 'observed' (I > 3σ(I)) reflections respectively. Also recorded are the syntheses and room-temperature single-crystal X-ray structure determinations for 1:1 aducts of 2,2':6',2"-terpyridine with lead(II) chloride, bromide and iodide, the chloride and bromide being hydrated. ( tpy )PbCl2.H2O is monoclinic, P 21/c, a 8.938(1), b 15,210(7), c 13.414(3) Ǻ, β 115.17(1)°, Z = 4 f.u .; R was 0.036 for No = 3346 independent, 'observed' reflections. The complex is centrosymmetric, binuclear [( tpy ) (H2O)( Cl ) Pb (μ- Cl )2Pb( Cl )(OH2)( tpy )], with the two lead atoms linked by bridging chlorine atoms; the lead atoms are seven-coordinate N3,O,ClPb(μ- Cl )2. The bromide ( tpy )PbBr2.2/3H2O, triclinic, Pī, a 12.360(6), b 12.452(4), c 18.372(6) Ǻ, α 108.31(3), β 109.44(3), γ 90.56(3)°, Z = 6 f.u ., R being 0.046 for No 7282, is in fact trinuclear [Pb3Br6( tpy )6].2H2O, a novel and elegant oligomer with quasi-2 symmetry in which a central lead atom (on the quasi-2 axis) is seven-coordinated [( tpy ) Pb (μ-Br)4] with the associated bromides bridging to a pair of peripheral lead atoms, also seven coordinated, [( tpy )(Br) Pb (μ-Br)3]. Unsolvated ( tpy )PbI2, triclinic, Pī , a 10.834(3), b 9.023(3), c 8.906(2) Ǻ, α 80.34(2), β 89.40(2), γ 79.78(2)°, Z = 2 f.u ., R 0.031 for No 2347 is, like the chloride, centrosymmetric binuclear, [( tpy )(I) Pb (μ-I)2Pb(I)( tpy )], but with the lead(II) now six-coordinate N3(I) Pb (μ-I)2. In both chloride and iodide, the tpy plane is approximately normal to the Pb ... Pb line with the water molecule of the chloride approximately trans to the central tpy nitrogen; in the iodide that site is occupied by the terminal halide.

Structural Systematics of Rare Earth Complexes. XXII. ('Maximally') Hydrated Rare Earth Iodides

2000 ◽  
Vol 53 (10) ◽  
pp. 867 ◽  
Author(s):  
Kevin C. Lim ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Aqueous Solution ◽  
Rare Earth ◽  
Low Temperature ◽  
Single Crystal ◽  
Room Temperature ◽  
Second Phase ◽  
X Ray ◽  
Structure Determinations ◽  
Trivalent Rare Earth ◽  
Trigonal Prismatic

Low-temperature (c. 153 K) single-crystal X-ray structure determinations, carried out on trivalent rare earth iodides crystallized from aqueous solution at room temperature, have defined two series of hydrates, LnI3.nH2O. For Ln = La–Ho, a nonahydrate phase (n = 9) is defined, orthorhombic Pmmn, a ~ 11.5, b ~ 8.0, c ~ 8.8 Å, Z = 2, the second phase (n = 10), monoclinic P21/c, Z = 4 being defined for Ln = Er–Lu, a ~ 8.2, b ~ 12.8, c ~ 17.1 Å, β ~ 103.7˚. Neither of these phases is isomorphous with any of those pertinent to the previously studied chloride or bromide (hydrated) arrays, nor, unlike those, does the halide (iodide) in any case enter the coordination sphere of the lanthanoid. The n = 9 phase takes the form [Ln(OH2)9]I3, the nine-coordinate lanthanoid environment stereochemistry being tricapped trigonal-prismatic, while the n = 10 phase is [Ln(OH2)8]I3.2H2O, the eight-coordinate lanthanoid environment being square-antiprismatic.

α-Sulfonyl Radical Initiated Intramolecular Tandem Radical Cyclization: Stereochemistries of a Pair of Doubly Cyclized Products

2003 ◽  
Vol 56 (7) ◽  
pp. 715 ◽  
Author(s):  
Lindsay T. Byrne ◽  
Manat Phomakotr ◽  
Chompoonut Poolsanong ◽  
Vichai Reutrakul ◽  
Brian W. Skelton ◽  
...  
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Radical Cyclization ◽  
X Ray ◽  
Structure Determinations

Room-temperature single-crystal X-ray structure determinations are recorded for trans-1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]-1-benzothiapyran-4,4-dioxide and its 3a-methyl analogue, minor products of the α-sulfonyl radical-initiated intramolecular tandem radical cyclization of H2C=CH(CH2)CRBrSO2Ph (R = H, CH3), confirming the assigned structures and rigorously establishing the trans relationship at the ring junctions.

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