Synthesis, structural and magnetic characterisation of tris(1-methyl-4,5-diphenylimidazol-2-yl)methanol (L) and [{CuL(NO3)}2][NO3]2
Abstract
Tris(1-methyl-4,5-diphenylimidazol-2-yl)methanol (L) has been
synthesized and characterised. It crystallises as L·0.5
1,2-Cl
2
C
2
H
4
from
1,2-Cl
2
C
2
H
4
–light petroleum and
its crystal structure has been determined. This compound reacts with
Cu(NO
3
)
2
·3H
2
O to yield
[{CuL(NO
3
)}
2
][NO
3
]
2
which has also been crystallographically characterised. Each
[{CuL(NO
3
)}
2
]
2+
is located on
a crystallographic inversion centre; the N
2
O
3
co-ordination sphere has a geometry intermediate between square
pyramidal and trigonal bipyramidal, with a slight bias towards the
former. The Cu(1)–O(1)–Cu(1*) bridging angle is small at
95.1(2)° and the Cu
···
Cu separation of 3.011(1) Å is typical of a coplanar-type
di-µ-oxo-copper(II) dimer. Magnetic susceptibility
(300–4 K) measurements indicated that the dimeric complex has a
spin-triplet ground state, i.e. the two copper(II)
ions are ferromagnetically coupled. Variable-temperature (300–4 K)
EPR spectroscopy confirmed an S = 1 ground state
described by the spin-Hamiltonian parameters
g
xx
= 2.09,
g
yy
= 2.08,
g
zz
= 2.24,
|D| = 0.35 cm
-1
and |E| = 0.049
cm
-1
at room temperature. The magnitude of the
zero-field splitting parameter |D| and the value
of 2J decrease with decreasing temperature.
···
Cu separation of 3.011(1) Å is typical of a coplanar-type
di-µ-oxo-copper(II) dimer. Magnetic susceptibility
(300–4 K) measurements indicated that the dimeric complex has a
spin-triplet ground state, i.e. the two copper(II)
ions are ferromagnetically coupled. Variable-temperature (300–4 K)
EPR spectroscopy confirmed an S = 1 ground state
described by the spin-Hamiltonian parameters
g
xx
= 2.09,
g
yy
= 2.08,
g
zz
= 2.24,
|D| = 0.35 cm
-1
and |E| = 0.049
cm
-1
at room temperature. The magnitude of the
zero-field splitting parameter |D| and the value
of 2J decrease with decreasing temperature.
Please wait while we load your content...
