Struct Chem (2010) 21:299–304
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(H2L ? H)?, 171 (LaH2LꢀCH3OH)3?; mmax(KBr)/cm-1
:
Figure 1 shows the anisotropic ellipsoid representations
of one of the symmetry-independent H3L? cations. Some
relevant geometric parameters are listed in Table 2.
3440, 866 (OH), 3108, 3060, 3010 (N–H), 1543 (C=N),
1573, 1459, 998, 647 (py), 1175 (N–N), 1088, 627 (ClO4-),
453 (La–N); dH(300 MHz; CD3CN): 9.22 (2H, NH), 8.43–
7.81 (6H, py), 7.26–6.85 (20H, phen), 2.49 (12H, CH3);
The geometry of the two H3L? cations is very similar and
the position of protonation is in both cases confirmed by the
successful refinement of hydrogen atom as well as by the
geometrical features of its neighborhood. The significant
differences between the symmetry-independent molecules
are found only at the level of their conformations. These can
be described by the dihedral angles between the planar
fragments: three rings I, II, and III and two planar bridging
fragments C(ar)–C=N–N–C(ar) (cf. Fig. 1, Table 2).
All these fragments are almost perfectly planar, with
the maximum deviation from the least-squares plane of
k
max(MeOH)/nm (e/dm3 mol-1 cm-1): 238.5 (36545), 349
(85827). Anal. Calc. (%) for Pr(HL)2(ClO4)ꢀ5H2O: C, 49.69;
H, 4.96; N, 13.80. Found (%): C, 49.99; H, 4.94; N, 13.60;
m/z (ESI): 344 (H2L ? H)?, 185 (PrH2Lꢀ4H2O)3?
;
m
max(KBr)/cm-1: 3400, 870 (OH), 3105, 3057, 3008 (N–H),
1541 (C=N), 1571, 1462, 999, 648 (py), 1176 (N–N), 1091,
624 (ClO4-), 430 (Pr–N); kmax(MeOH)/nm (e/dm3 mol-1
cm-1): 220 (22490), 348.5 (47338). Anal. Calc. (%) for
Nd(HL)2(ClO4)ꢀ3H2O: C, 51.34; H, 4.72; N, 14.26. Found
(%): C, 51.77; H, 4.77; N, 14.08; m/z (ESI): 344 (H2L ? H)?,
173 (NdH2Lꢀ4CH3OH)3?, 283 (NdH2LꢀH2O)3?; mmax(KBr)/
cm-1: 3439, 870 (OH), 3110, 3050, 3012 (N–H), 1542 (C=N),
1575, 1472, 997, 647(py), 1174(N–N), 1101, 627 (ClO4-), 435
(Nd–N); kmax(MeOH)/nm (e/dm3 mol-1 cm-1): 220 (22752),
348.5 (53091).
˚
0.0105(11) A, with the noticeable exception of fragment
C6B–C61B=N61B–N62B–C63B which is significantly
folded (deviations from the mean plane as large as
˚
0.0735(10) A). Molecule B is significantly more folded than
A (Fig. 2); Table 2 lists some of the relevant torsion angles.
It might be noted that while one part of the molecule is
similar, the other part is fairly different.
In situ synthesis of La(III) perchlorate complex of H2L
In the crystal structure, the electrostatic interactions
between charged species and relatively weak hydrogen bonds
(Table 3) are the main factors determining the packing.
Independent molecules make separate and different
motifs. Cation A with anion A and water molecule create a
hydrogen-bonded ‘‘ladder’’ which extends along the [100]
direction (Fig. 3a). In contrast, cation B with anions B
make hydrogen-bonded centrosymmetric dimers which do
not expand further (Fig. 3b).
To a mixture of 2,6-diacetylpyridine (16.3 mg, 0.1 mmol) in
methanol (5 mL) and phenylenehydrazine (0.0362 mL,
0.2 mmol) in methanol (5 mL), lanthanum(III) perchlorate
hexahydrate (54.5 mg, 0.1 mmol) was added dropwise with
stirring. The reaction was carried out for 24 h. The resulting
red precipitate was filtered off, washed with ether, and dried
on air. Yield: 55%. Anal. Calc. (%) for La(HL)2(ClO4)3ꢀ
3H2O: C, 51.62; H, 4.74; N, 14.33. Found (%): C, 52.47; H,
4.64; N, 14.43; m/z (ESI): 344 (H2L ? H)?, 171 (LaH2Lꢀ-
CH3OH)3?; mmax(KBr)/cm-1: 3440, 866 (OH), 3105, 3060,
3010 (N–H), 1540 (C=N), 1580, 1460, 998, 647 (py), 1175
(N–N), 1090, 622 (ClO4-), 451 (La–N); dH(300 MHz;
CD3CN): 9.16 (2H, NH), 8.43–7.80 (6H, 9.29–6.88 (20H,
phen), 2.49 (12H, CH3); kmax(MeOH)/nm (e/dm3 mol-1
cm-1): 238.5 (14316), 349 (34520).
Results and discussion
2,6-diacetylpyridinediphenylhydrazone with the set of
potential NNN donor atoms was obtained as its perchlorate
salt by the Schiff base condensation of 2,6-diacetylpyridine
with phenylhydrazone and identified by spectral data and
X-ray crystal structure determination. The formulation of
this compound as H3LꢀClO4ꢀ0.5H2O is in agreement with
elemental analysis data.
In the crystal structure there are two cations and two
anions in the asymmetric part of the unit cell and one water
molecule; thus this compound may be formulated as
Fig. 1 Perspective view of one of the H3L? cations (A) together with
the labelling scheme [20]. Ellipsoids are drawn at the 50% probability
level; hydrogen atoms are shown as spheres of arbitrary radii
2H3L?ꢀ2ClO4 ꢀH2O (Table 1).
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