Author:
Semenova Lioubov I.,Sobolev Alexander N.,Skelton Brian W.,White Allan H.
Abstract
Room-temperature single-crystal X-ray structure determinations of the 1 : 3
adducts of the trivalent lanthanoid perchlorates with
2,2′:6′,2″-terpyridine (‘tpy’) as crystallized
from acetonitrile are recorded. The Ln = La complex is the only one of
its structural type, being modelled as
La(ClO4)3/tpy/MeCN/H2O
(1 : 3 : 2 :2/3), trigonal P
3c1, Z = 6,
a 13·063(7), c
53·04(4) Å, recorded on an interim basis, with conventional
R on |F|
0·081 for No 2889
‘observed’ (I
>3σ(I)) reflections. For Ln = Ce, (Pr,
Sm,) Eu and, by presumption, other intermediate members, a monosolvate is
found, monoclinic P
21/n, a
≈ 9·3, b ≈ 21·1,
c ≈ 24·7 Å, β ≈ 91°,
Z = 4, R being
0·045, (0·060, 0·049,) 0·047 for
No 4420, (4199, 3931,) 3713. The
Ln = Eu adduct has also been obtained unsolvated in a form
representative of Ln = Eu, Lu and, by presumption, intermediate
members, as well as Y, which is monoclinic C
2/c, Z = 4,
R being 0·051, 0·044, 0·061 for
No 4386, 4407, 3713. All
monoclinic systems are of the form [Ln(tpy)3]
(ClO4)3(.S),
Ln being nine-coordinate, and in the case of the C
2/c phase lying on a crystallographic
2 axis. The Ln = La adduct was modelled with
three independent cations, all with crystallographic 3
symmetry, two with their coordination number augmented by the approach of
solvent along the 3 axis.