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.
