680
Short Communications
Table 7. Pendant carbon angles and phenyl torsion angles in Ph8Sb4O6
Feature
Atoms
Angles/degrees (mols 1; 2)
Pendant carbon angles
Sb(1)–C(111)–C(112,6)
Sb(1)–C(121)–C(122,6)
Sb(2)–C(211)–C(212,6)
Sb(2)–C(221)–C(222,6)
123(1), 119(1); 122(1), 118(1)
123(1), 121(1); 121(1), 121(1)
119(1), 122(1); 117(1), 123(1)
121(1), 121(1); 120(1), 124(1)
Phenyl torsion angles
O(2)–Sb(1)–C(111)–C(112,6)
O(2)–Sb(1)–C(121)–C(122,6)
O(2)–Sb(2)–C(211)–C(212,6)
O(2)–Sb(2)–C(221)–C(222,6)
37(2), ꢁ148(1); 38(2), ꢁ144(1)
91(1), ꢁ87(1); 93(1), ꢁ90(2)
156(1), ꢁ27(1); 143(1), ꢁ33(1)
79(3), ꢁ101(3); 94(3), ꢁ87(3)
cell is well behaved. Further, we record a new phase
(‘ꢀ’) of triphenylstibine, obtained from hexane/toluene
solution.
compounds of the type XPh3SbOSbPh3X, X = halide
or pseudo-halide, viz. Cl (as benzene solvate),4 Br,7
N3,8 are summarized geometrically in company with the
present in Table 5. Also worthy of passing note is the
very recent structural record of binuclear homologues
[XPh2Sb(ꢄ-O)2/2]2.9 Geometries of the present two
systems are given in detail in Table 5; the molecules
are depicted in Figs 1 and 2. Features initially worthy of
note are the ‘staggered’ disposition of the phenyl groups
in projection down the Sbꢀ ꢀ ꢀSb line, the substantial
diꢃerences in the Sb–O–Sb angles, and the unidentate
coordination of the nitrate groups in that complex,
involving unusually lengthened N–O distances.
Of particular note is the characterization of a sec-
ond phase of the chloride and the observation of a
remarkable diꢃerence in the angles subtended at the
central oxygen atom by the two antimony atoms, these
being 139ꢀ0(3)ꢀ in the previously studied benzene
solvate4 and 173ꢀ1(3)ꢀ in the present. By a remark-
able coincidence, the results of an equally remarkable
contemporary study have just appeared, recording the
structural characterization of two polymorphs of the
iodide analogue,5 neither being isomorphous with the
present chloride. The two iodide polymorphs display
angles of 180ꢀ and 144ꢀ6(4)ꢀ at the central oxygen, the
variation in angle correlating with variations in Sb–O
Structure Determination
General procedures are given in ref. 1; speciꢁc details are
as follows (see also Tables 1–7 and Figs 1–4).
(1) [(Cl)Ph3SbOSbPh3(Cl)]. C36H30Cl2OSb2, M 793ꢀ0.
Monoclinic, space group P 21/c (C25h, No. 14), a 9ꢀ109(4),
ꢀ
ꢀ
ꢀ3
b 19ꢀ809(8), c 19ꢀ30(2) A, ꢀ 109ꢀ27(5) , V 3287 A . Dc(Z = 4
f.u.) 1ꢀ60 g cmꢁ3; F(000) 15ꢂ60. ꢁMo 16ꢀ9 cmꢁ1; specimen:
0ꢀ46 by 0ꢀ40 by 0ꢀ39 mm; Amin,max 1ꢀ66, 1ꢀ81. 2ꢂmax 50ꢀ;
N 5757, N o 4431; R 0ꢀ038, Rw 0ꢀ044.
(2) [(O2NO)Ph3SbOSbPh3(ONO2)].C7H 8. C43H38N2O7-
Sb2,
M
937ꢀ9. Triclinic, space group P 1 (Ci1, No. 2),
ꢀ
a 15ꢀ609(5), b 13ꢀ238(4), c 10ꢀ140(2) A, ꢃ 87ꢀ11(2), ꢀ 88ꢀ46(7),
ꢄ 72ꢀ93(2) , V 2001 A . Dc(Z = 2 f.u.) 1ꢀ56 g cmꢁ3; F(000)
936. ꢁMo 14ꢀ0 cmꢁ1; specimen: 0ꢀ32 by 0ꢀ14 by 1ꢀ00 mm;
Aꢂmin,max 1ꢀ20, 1ꢀ60. 2ꢂmax 50ꢀ; N 7026, N o 5275; R 0ꢀ036,
Rw 0ꢀ039.
ꢀ3
ꢀ
Variata for (2). The toluene molecule, although exhibiting
high thermal motion, reꢁned to unit population and with no
overt disorder; in ꢁnal reꢁnement cycles it was modelled as a
rigid body.
(3) Ph8Sb4O6. C48H40O6Sb4, M 1199ꢀ5. Triclinic, space
ꢀ
group P 1, a 19ꢀ698(3), b 11ꢀ635(2), c 9ꢀ739(2) A, ꢃ 92ꢀ28(1),
ꢀ
ꢀ3
ꢀ 98ꢀ98(1), ꢄ 99ꢀ74(1) , V 2168 A . Dc(Z = 2 f.u.) 1ꢀ84
g cmꢁ3; F(000) 1160. ꢁMo 25ꢀ4 cmꢁ1; specimen: 0ꢀ10 by
0ꢀ24 by 0ꢀ18 mm; Aꢂmin,max 1ꢀ15, 1ꢀ63. 2ꢂmax 45ꢀ; N 5295,
N o 3578; R 0ꢀ046, Rw 0ꢀ047.
ꢀ
(4) Ph3Sb. C18H15Sb, M 353ꢀ1. Monoclinic, space group
(1ꢀ9410(6), 1ꢀ9437(6) versus 1ꢀ986(8), 1ꢀ956(8) A) and
ꢀ
ꢀ
P 21/c, a 15ꢀ386(8), b 11ꢀ304(5), c 19ꢀ078(8) A, ꢀ 111ꢀ64(4) ,
ꢀ
Sb–I (2ꢀ954(1), 2ꢀ968(1) versus 2ꢀ991(3), 2ꢀ995(1) A);
ꢀ3
V
3084 A . Dc(Z = 8) 1ꢀ52 g cmꢁ3
; F(000) 1392. ꢁMo
counterpart values in the chloride systems for Sb–O
17ꢀ7 cmꢁ1; specimen: 0ꢀ55 by 0ꢀ20 by 0ꢀ35 mm; Aꢂmin,max
ꢀ
are 1ꢀ965(4), 1ꢀ951(4) versus 1ꢀ980(6), 1ꢀ986(6) A,
1ꢀ41, 1ꢀ84. 2ꢂmax 50ꢀ; N 5427, N o 3393; R 0ꢀ045, Rw 0ꢀ046.
supporting a similar correlation with change in angle.
In both sets of examples, the angular values of linearity
and c. 140ꢀ correspond to the dichotomy deꢂned for
such compounds by Glidewell.10
Discussion
Given the histories of the materials, the results of the
room-temperature single-crystal X-ray studies of the
ꢂrst two complexes are consistent in likely stoichiometry
and connectivity with their formulation as members
of the well known family of oxo-bridged antimony(V)
compounds X(Ph3Sb)O(SbPh3)X, two ꢂve-coordinate
antimony(V) species being bridged by an oxygen atom
lying axially trans in a quasi-trigonal bipyramidal
coordination sphere to a unidentate anion, the three
phenyl groups being equatorial; the anions are chloride
and O-nitrate respectively, the latter complex being
produced as a toluene solvate. A considerable variety
of related compounds has been structurally charac-
terized; those considered most relevant, comprising
The structural characterization of ‘Ph8Sb4O6’ resides
in the literature in two forms; one, recorded as
[(Ph8Sb4O6).(HOAc)3] dichloromethane solvate,11 is a
true tetranuclear basic acetate and, as such, not strictly
comparable with the ‘unsolvated’ bare parent. The
latter has been recorded in a triclinic cell; a 11ꢀ677(5),
ꢀ
b 9ꢀ745(3), c 10ꢀ586(6) A, ꢂ 99ꢀ69(4), ꢀ 113ꢀ35(3),
ꢀ
3
ꢀ
ꢃ 87ꢀ56(3) , V 1090 A , Z = 1 f.u.; the structure
was reꢂned to a residual of 0ꢀ051 for 2175 ‘observed’
(I > 3ꢁ(I)) reꢁections in terms of a model involving
a pair of essentially identical tetranuclear molecules
superimposed and centred about a common inversion
centre and disordered 50 : 50 in that manner.6 The
Effendy
