3912
T.-Y. Chien et al. / Polyhedron 28 (2009) 3907–3914
C58H41N5O2Zn. Moreover, the eight hydrogen atoms in solvent tolu-
ene are not refined in Cu (II) complex of 6, hence its empirical for-
mula is C58H33CuN5O2. Table 2 lists selected bond distances and
angles for complexes 4ꢀC6H5CH3, 5ꢀ0.6CHCl3, 6ꢀC6H5CH3, and
8ꢀCH2Cl2ꢀMeOH.
3.2. Intramolecular hydrogen bonding
Hydrogen bonding results in downfield shifts of proton reso-
nances from their positions in the unbounded state. The low-field
values of phenols at d 11.18–11.95 ppm for 3, 4 and 5 are attrib-
uted to intramolecular hydrogen bonding (Table 3). Intramolecular
hydrogen bonding in 3, 4 and 5 involves the nonbonding electron
of the carbonyl oxygen. As a result, the carbonyl carbon that be-
comes more positive, led to a deshielding of about 4.7 ppm from
162.8 ppm for 7 to 166.0–168.2 ppm for 3, 4 and 5 (Table 3) [2].
3. Results and discussion
3.1. Structures of 4–6, 8
The X-ray framework is depicted in Fig. 1b for 6, in Fig. 2 for
complexes 4 and 5 and in Fig. 3 for complexes 7 and 8 (Figs. S1–
S3 in Supplementary data) [2]. All these structures, four-coordi-
nate, distorted square planar (DSP) geometrical zinc of 4 (or nickel
of 5, copper of 6) and five-coordinate gallium of 7 (or manganese of
8) have bonding with three nitrogen atoms of the porphyrins and
one extra nitrogen atom of the nitrene fragment in common but
compounds 7 and 8 have in addition one more Oꢁ [(o-O)BA-Ph] li-
gand in the axial site. The metal-ligand bond distances and the an-
gles are summarized in Table 2.
3.3. ESR studies
Complex 6 is paramagnetic because of the d9 configuration of
Cu(II). The unpaired electron resides in the dx2
leads to characteristic ESR spectra for 6 in CHCl3 at 20 °C: four
peaks due to the nuclear spin (I = 3/2) of the Cu and a nine-line pat-
tern due to the super hyperfine interactions with the four nitro-
gens (I = 1) of the porphyrin. The ESR spectra are typical for
orbital, which
ꢁy2
planar copper (II) complex with giso = 2.04, Aiso
and Aiso
14N) = 12.6 G for 6 in CH2Cl2 at 20 °C and with g|| = 2.19
and A||
63Cu) = 179.4 G for 6 in CH2Cl2 at 77 K (Fig. S4 in Supple-
mentary data). These hyperfine couplings are similar in magni-
tudes to those of giso = 2.086, Aiso and Aiso
63Cu) = 86.5
14N) = 14.4 G obtained from Cu(OETPP) in CH2Cl2 solution at
298 K [12].
(
63Cu) = 85.7 G,
(
The distortion in five-coordinate complex 8 can be quantified by
(
the ‘‘degree of trigonality” which is defined as
b is the largest and the second largest of the Lbasal–M–Lbasal angles
[10]. The limiting values are = 0 for an ideal tetragonal geometry
and = 1 for an ideal trigonal bipyramid. In the present case, we
find b = 178.35(8) [N(5)–Mn–N(2)] and = 144.71(7) [N(1)–Mn–
N(3)] for 8ꢀCH2Cl2ꢀMeOH. Thus values calculated for
8ꢀCH2Cl2ꢀMeOH is 0.56. This value is close to that of 0.57 for 7
s
= (b ꢁ
a)/60, where
a
(
G
s
(
s
a
The X-band (9.426 GHz) ESR spectrum using parallel polariza-
tion recorded for 8 in powder solid at 20 °C is shown in Fig. 4. As
has been similarly observed in other Mn(III) complexes, the single
line centered at ꢄ814 G is found. This signal is attributed to a for-
s
s
[2]. Hence the geometries around Mn(III) in 8ꢀCH2Cl2ꢀMeOH are
best described as a distorted trigonal bipyramid (DTBP) (or a
square-based pyramidally distorted trigonal bipyramid, SBPDTBP)
with O(1) N(1), and N(3) lying in the equatorial plane for
8ꢀCH2Cl2ꢀMeOH [11].
ꢀ
ꢀ
þꢁ
bidden transition within the 2 and j2ꢁi non-Kramber’s doublet
for the high-spin mononuclear Mn3+ (S = 2) complex (Fig. 4) [13].
We adopt the plane of the three strongly bound pyrrole nitro-
gen atoms [i.e., N(1), N(2) and N(3)] as a reference plane 3N for
4–8. The benzamide nitrogen N(5) in 4–8 is located considerably
far from the 3N plane. In 4–6, Zn2+ (or Ni2+, Cu2+) and N(5) are lo-
cated on the same sides at 0.35 (or 0.18, 0.30) and 1.53 (or 0.84,
1.24) Å from its 3N plane for complexes 4(or 5, 6), respectively.
In 7–8, Ga3+ (or Mn3+) and N(5) are also located on the same sides
at 0.67 (or 0.58) and 1.11 (or 1.09) Å from its 3N plane for 7 (or 8),
respectively (Table 3) (Fig. S5 in Supplementary data) [2]. The N(4)
pyrrole rings bearing the BA group in 4–8 could deviate mostly
from the 3 N plane, orienting separately in a dihedral angle of
36.4° (or 41.3°, 30.4°) for 4 (or 5, 6) and of 37.5° (or 38.6°) for 7
(or 8) (Table 3) [2].
3.4. Magnetic properties
A single band for the absorption spectrum of 8 is found to occur
at 463.9 nm. With the band assignment 5Eg ? 5T
we then get
2g
Dq = 2156 cmꢁ1 for 8. Magnetic data for complex 8 are reported
in Fig. 5 in the forms of vM and leff versus T. As can be seen in
Fig. 5, the value of leff varies from 4.50 lB at 300 K to 3.81 lB at
2 K. The magnetic moment clearly shows a plateau equal to 4.50
lB at high temperature (300–30 K), below which it rises slowly
to 4.52 lB at 20 K before decreasing again. The abrupt rise in leff
in the range 2 < T < 20 K is characteristic of compound 8 with sig-
nificant zero-field splitting (ZFS). The room-temperature effective
moment of 4.50 lB is lower than the spin-only moment of 4.9 lB
Table 3
1H, 13C NMR (20 °C), X-ray data and Z values for complexes 3–8.
d
Compounds
rion (Å)
X-ray
1H NMR (o-OH)
BA-Ph (ppm)
OH
13C NMR (o-OH)
BA (ppm)
BA–CO
Z
[6]
Classification
of metal ionse[6]
a
D
(3N)
Mꢀ ꢀ ꢀO(2)b
hc (o)
Coordination
geometry
(Å)
[or Mn3+ꢀ ꢀ ꢀO(1)] (Å)
Cu2+ in 6
0.71
0.63
0.74
0.30
0.18
0.35
5.639
5.677
5.707
36.4
41.3
30.4
28.6
37.5
38.6
DSPf
DSP
DSP
0.177
0.293
0.656
B
B
B
Ni2+ in 5 (in CD2Cl2)
Zn2+ in 4 (in CD2Cl2)
3 (in CDCl3)2
11.18
11.49
11.95
168.2
166.0
168.2
162.8
Ga3+ in 7 (in CDCl3)2
Mn3+ in 8
0.69
0.72
0.67
0.58
1.880(4)
1.9666(16)
DTBPg
DTBP
1.167
1.698
E
E
a
b
c
d
e
f
D
(3N) denotes the displacement of the metal center from the 3N plane.
M = Zn2+,Ni2+, Cu2+, Ga3+
.
h: dihedral angle between the pyrrole ring bearing a (o-OH)BA group and the 3N plane.
Z: Zhang’s scale for strengths of Lewis acids [6].
Electrostatic or covalent nature of Lewis acids. B acids = border acids, E acids = large electrostatic acids [6].
DSP = distorted square planar.
g
DTBP = distorted trigonal bipyramid.
Chien, Ting-Yuan
