L. Zhang et al. / Inorganica Chimica Acta 384 (2012) 225–232
227
(
m, 12H). 31P NMR d +1.70 (s). Anal. Calc. for C58
4 4 2
H42BCuF N P : C,
6
9.16; H, 4.20; N, 5.56. Found: C, 69.27; H, 4.28; N, 5.43%.
1
4 3
[Cu(Pyphen)(POP)]BF : H NMR (300 Hz, CDCl , 25 °C): d 9.50 (d,
2
2
C
4
H, J = 8.0 Hz), 9.28 (d, 2 H, J = 8.0 Hz), 9.00 (s, 2 H), 7.88–7.76 (m,
0 H), 7.37–7.33 (m, 10H). 31P NMR d +1.65 (s). Anal. Calc. for
50
H
36BCuF
.01; N, 6.17%.
4 3
Cu(DPPZ)(POP)]BF , 25 °C): d 9.63 (d,
: 1H NMR (300 Hz, CDCl
4 4 2
N OP : C, 65.19; H, 3.94; N, 6.08. Found: C, 65.11; H,
[
2
7
H, J = 8.0 Hz), 9.28 (d, 2H, J = 8.0 Hz), 8.32 (d, 2H, J = 6.4 Hz),
.91–7.78 (m, 22H), 7.35–7.30 (m, 10H). 31P NMR d +1.66 (s). Anal.
Calc. for C54
6
H
38BCuF
6.71; H, 3.78; N, 5.84%.
Cu(BDPZ)(POP)]BF
1H NMR (300 Hz, CDCl
H, J = 8.0 Hz), 9.25 (d, 2H, J = 8.0 Hz), 8.97 (s, 2H), 8.20 (d, 2H,
4 4 2
N OP : C, 66.78; H, 3.94; N, 5.77. Found: C,
[
4
:
3
, 25 °C): d 9.68 (d,
2
31
J = 8.0 Hz), 7.89–7.77 (m, 22H), 7.36–7.30 (m, 10H). P NMR d
1.63 (s). Anal. Calc. for C58 40BCuF OP : C, 68.21; H, 3.95; N,
.49. Found: C, 68.40; H, 3.84; N, 5.56%.
+
5
H
4
N
4
2
2.3. Computational methods and measurements
DFT calculations were performed on the three diimine ligands,
Pyphen, DPPZ and BDPZ, using RB3LYP/6-31G(d). Singlet excitation
calculations on [Cu(N–N)(PPh ]BF , where N–N = Pyphen, DPPZ,
3
)
2
4
and BDPZ, were performed by TD-DFT using RB3LYP/SBKJC. The
initial geometries were obtained from single crystal data of their
corresponding complexes. All the computations were finished by
PC GAMESS.
3 2 4
Fig. 1a. Structure of [Cu(Pyphen)(PPh ) ]BF .
Excited state lifetimes were obtained with a 355 nm light gen-
erated from the Third-Harmonic-Generator pumped, which using
pulsed Nd:YAG laser as excitation source. The Nd:YAG laser pos-
ꢀ1
sesses a line width of 1.0 cm , pulse duration of 10 ns and repeti-
tion frequency of 10 Hz. A Rhodamine 6G dye pumped by the same
Nd:YAG laser was used as the frequency-selective excitation
source. All the photoluminescence (PL) spectra were measured
with a Hitachi F-4500 fluorescence spectrophotometer. UV–Vis
absorption spectra were recorded using a Shimadzu UV-3101PC
1
31
spectrophotometer. H and P NMR spectra were obtained with
the use of a Varian INOVA 300 spectrometer. Elemental analyses
were performed on a Carlo Erba 1106 elemental analyzer. Single
crystals data were collected on a Siemens P4 single-crystal X-ray
diffractometer with a Smart CCD-1000 detector and graphite-
monochromated Mo K
a radiation, operating at 50 kV and 30 A at
2
98 K. All hydrogen atoms were calculated. All measurements
were carried out in the air at room temperature without being
specified.
3
. Results and Discussion
3 2 4
Fig. 1b. Structure of [Cu(DPPZ)(PPh ) ]BF .
3
.1. Geometric structures of [Cu(N–N)(P–P)]BF complexes
4
indicating a weak interaction between oxygen atom and Cu(I) cen-
ter. Similar Cu. . .O separations have also been reported in POP-
based Cu(I) complexes that contain 1,10-phenanthroline and de-
rived ligands [20,22].
Crystal structures of [Cu(N–N)(PPh
3
)
2
]BF
4
and [Cu(N–
N)(POP)]BF , where N–N = Pyphen, DPPZ, and BDPZ, are depicted
4
in Figs. 1a–1f. Geometric parameters summarized in Table 1
suggest that the Cu(I) center in all six complexes has a distorted
tetrahedral geometry. The dihedral angles between N–Cu–N and
P–Cu–P planes for the six complexes are measured to be 87.43°,
N–Cu–N bond angles of the Cu(I) complexes, except for
[Cu(DPPZ)(POP)]BF
little variation. As for [Cu(DPPZ)(POP)]BF
4
, are quite similar to each other (ꢁ80°) with a
4
, the N–Cu–N bond angle
8
7.91°, 88.72°, 78.54°, 89.58°, and 86.59°, respectively. Cu–N bond
lengths of the six Cu(I) complexes localize in a region of 2.05–
.11 Å which are comparable to literature values [20,22]. It is also
observed that Cu–N bond lengths in POP system are usually shorter
than those in PPh system, indicating a stronger Cu–N bond in POP
is somewhat greater, 81.2°, clearly due to reduced static congestion
caused by the large dihedral angle between N–Cu–N and P–Cu–P
2
planes of [Cu(DPPZ)(POP)]BF
angle varies dramatically from 112.69° for [Cu(BDPZ)(POP)]BF
124.15° for [Cu(Pyphen) (PPh ]BF as shown in Table 1. Consider-
4
(89.58°). In contrast, P–Cu–P bond
4
to
)
2
4
3
3
system. On the other hand, Cu–P bond lengths of the six Cu(I) com-
plexes are similar to each other. The oxygen atom of POP ligand in
ing POP’s natural bite angle of 102.2°, with a flexibility range from
86° to 120°, these large P–Cu–P bond angles in POP-based Cu(I)
complexes suggest a crowded coordination environment at Cu(I)
center [23].
[
Cu(N–N)(POP)]BF
4
complexes localizes at a distance of ꢁ3 Å from
the Cu(I) center and opposite to that of coordinated N atoms,