1416
S.K. Shukla et al. / Polyhedron 25 (2006) 1415–1420
IR spectra were recorded on a Pye Unicam SP3-300
solvent. The residue was crystallized by petroleum–ether
(40–60 °C) to afford (C6F5)2Sb(C6H4CH3-p) (2), yield
7.548 g (69%), m.p. 93 °C.
spectrophotometer over the spectral range 4000–200 cmꢀ1
1
in the solid state using KBr/CsI Pellets. H, 19F and 13C
NMR spectra were recorded on Jeol JNM-400 NMR spec-
trometer using TMS, CF3COOH and CDCl3 as references,
respectively. Antimony was determined according to a lit-
erature method [11]. Molecular weights were determined
cryoscopically in nitrobenzene using a Beckman thermom-
eter of 0.01 accuracy. The molar conductance of 10ꢀ3 M
solution of the compounds was determined at 25 °C with a
Khera DC610 Digital conductivity meter in methanol.
The FAB mass spectra were recorded on Jeol SX 102
mass spectrometer using DA-6000 data analysis system.
Argon was used as bombarding gas at 6 kV, 10 mA. The
accelerating voltage was kept at 10 kV. m-nitrobenzyl alco-
hol (NBA) was used as matrix.
2.2.3. Synthesis of (C6F5)2Sb(C6H5)
A solution of bromobenzene (3.140 g, 0.02 mol) in dry
diethyl ether was added drop wise to magnesium turnings
(0.486 g, 0.02 mol) embedded in diethyl ether under nitro-
gen atmosphere at 0 °C. The resulting Grignard solution
was cooled upto ꢀ10 °C and a solution of (C6F5)2SbCl
(9.826 g, 0.02 mol) in dry diethyl ether was slowly added
with constant stirring. The mixture was stirred for an addi-
tional 1 h at room temperature and subsequently refluxed
for 1 h more. The mixture was then cooled to 0 °C and
treated with ice water containing NH4Cl and subsequently
followed by the addition of 4 N HCl (1 ml) and stirred to
make the solution acidic. The ether layer was separated
and the aqueous brownish layer was further extracted with
chloroform. The organic layers were then mixed and kept
over anhydrous Na2SO4 overnight. The organic layer was
filtered and the filtrate was distilled on an oil-bath to
remove the solvent. The residue was crystallized by petro-
leum–ether (40–60 °C) to afford (C6F5)2Sb(C6H5) (3), yield
7.035 g (66%), m.p. 89–90 °C.
2.2. Representative synthetic procedures
2.2.1. Synthesis of (C6F5)2SbCH3
A solution of iodomethane (2.839 g, 0.02 mol) in dry
diethyl ether was added drop wise to magnesium turnings
(0.486 g, 0.02 mol) embedded in diethyl ether under nitro-
gen atmosphere at 0 °C. The resulting Grignard solution
was cooled upto ꢀ10 °C and a solution of (C6F5)2SbCl
(9.826 g, 0.02 mol) in dry diethyl ether was slowly added
with constant stirring. The mixture was stirred for an addi-
tional 1 h at room temperature and subsequently refluxed
for 1 h more. The mixture was then cooled to 0 °C and
treated with ice water containing NH4Cl and subsequently
followed by the addition of 4 N HCl (1 ml) and stirred to
make the solution acidic. The ether layer was separated
and the aqueous brownish layer was further extracted with
chloroform. The organic layers were then mixed and kept
over anhydrous Na2SO4 overnight. The organic layer was
filtered and the filtrate was distilled on an oil-bath to
remove the solvent. The residue was crystallized by petro-
leum–ether (40–60 °C) to afford pale yellow crystals of
(C6F5)2Sb(CH3) (1), yield 6.87 g (73%), m.p. 98–99 °C.
Similarly the (C6F5)Sb(C6H5)2 (4) was prepared by using
Grignard reagent (C6H5MgBr) and (C6F5)SbCl2.
(C6F5)2Sb(C6H5) and (C6F5)Sb(C6H5)2 were also pre-
pared by the reaction of C6F5MgBr with C6H5SbCl2 and
(C6H5)2SbCl, respectively, and the yields were 47% and
26%, respectively. These compounds were synthesized in
the same reaction conditions as described earlier for other
compounds.
2.2.4. Reaction of (C6F5)2Sb(C6H5) and Cl2 gas
Dry chlorine gas (generated by reaction of KMnO4 and
conc. HCl) was bubbled in a solution of (C6F5)2Sb(C6H5)
(5.33 g, 10 mmol) in petroleum–ether (60–80 °C) at 0 °C
under moisture free and nitrogen atmosphere with constant
stirring. White precipitate was started to settle down and
the bubbling of Cl2 gas was stopped as soon as pale yellow
colour in the solution persist and the reaction mixture was
further stirred for 30 min at room temperature, afterwards
the solvent was filtered off. The precipitate was washed
thrice with petroleum–ether (60–80 °C) to remove unre-
acted (C6F5)2Sb(C6H5). The precipitate was characterized
as (C6F5)2(C6H5)SbCl2 (9), m.p. 207 °C, yield 4.89 g (81%).
Similarly the dichlorides of (C6F5)2Sb(CH3), (C6F5)2-
Sb(C6H4CH3-p) and (C6F5)Sb(C6H5)2 were obtained.
2.2.2. Synthesis of (C6F5)2Sb(C6H4CH3-p)
p-Bromotoluene (3.421 g, 0.02 mol), dissolved in dry
diethyl ether was added drop wise to magnesium turnings
(0.486 g, 0.02 mol) embedded in diethyl ether under nitro-
gen atmosphere at 0 °C. This Grignard solution was cooled
upto ꢀ10 °C and a solution of (C6F5)2SbCl (9.826 g,
0.02 mol) in dry diethyl ether was slowly added with con-
stant stirring. The mixture was stirred for 2 h at room tem-
perature and subsequently refluxed for 1 h more. The
mixture was then cooled to 0 °C and treated with ice water
containing NH4Cl and subsequently followed by the addi-
tion of 4 N HCl (1 ml) and stirred to make the solution
acidic. The ether layer was separated and the aqueous
brownish layer was further extracted with chloroform.
The organic layers were then mixed and kept over anhy-
drous Na2SO4 overnight. The organic layer was filtered
and the filtrate was distilled on an oil-bath to remove the
2.2.5. Reaction of (C6F5)2Sb(C6H5) and liquid Br2
Solution of liquid bromine (1.6 g, 10 mmol) in petro-
leum–ether (60–80 °C) was added drop wise into a pre-
cooled (0 °C) solution of (C6F5)2Sb(C6H5) (5.3 g, 10 mmol)
in petroleum–ether (60–80 °C) (100 ml) under nitrogen
atmosphere with constant stirring. After each drop of addi-
tion of liquid bromine, yellow colour disappeared, as soon
as the colour of bromine persists, the addition was stopped.