Z. Wang et al. / Inorganic Chemistry Communications 12 (2009) 511–514
513
0
interactions between the Cl and the NH amide groups, with a
In summary, two new ligands, HLPhOH and HLPhOH , were de-
signed and synthesized as an extension to our previous work.
Two multinuclear copper(II) complexes, 1 and 3, were synthesized
and characterized. In both complexes, the ligands have similar
Nꢁ ꢁ ꢁCl distance of 3.261 Å and a N–Hꢁ ꢁ ꢁCl bond angle of 156°.
0
Binuclear complex [Cu2(LPhO )2(CH3OH)] (3) was prepared by
the same synthetic method as complex 1 using Cu(OTf)2 and
0
Et3N in CH3OH, but substituting the HLPhOH ligand for HLPhOH
coordination modes, coordinating via the pyridyl N, amidate N,
0
[13,19]. In contrast to 1, the structure of 3 (Fig. 3) is significantly
and phenoxo O atoms. The differences between HLPhOH and HLPhOH
different, with a binuclear structure that consists of two copper
have some important steric effects on the nuclearity of the copper
0
ions and two deprotonated ligands (LPhO
)
2ꢀ. The two copper atoms
complexes. In tetranuclear 1, (LPhO 2ꢀ
) forms a five-membered ring
are bridged by two phenoxo O atoms, forming a Cu2O2 core struc-
ture. Each copper is five-coordinate with two N donors (pyridyl
and amidate) and one phenoxo O donor from one ligand, and a
phenoxo O donor from the second ligand making up the basal
plane. The fifth coordination site is occupied by a methanol solvent
molecule in the axial position, forming a distorted square pyrami-
dal geometry, which is supported by a s5 value of 0.180 for 3,
where a value of 0.0 corresponds to perfect square pyramidal
and a value of 1.0 corresponds to perfect trigonal bipyramidal
[20]. The Cu–OMeOH bond length of 2.3476(14) Å is longer than
the Cu–Ophenoxo and Cu–N bond lengths in 3. The basal positions
are occupied by two N atoms and two O atoms from the ligands.
The N2O2 donor set is almost planar, and the Cu1 and Cu1A centers
are displaced from the N2O2 mean plane by 0.1076 Å and 0.1215 Å,
respectively, toward the coordinated methanol solvents. The
Cuꢁ ꢁ ꢁCu distance is 3.062 Å, which is similar to other reported
phenoxo-bridged dicopper complexes [16,17,21–23].
The magnetostructural relationship in phenoxo-bridged binu-
clear copper complexes has been widely investigated. The effective
magnetic moment (leff) of complex 3 is 1.879 BM/Cu, which sug-
gests no antiferromagnetic interaction between the two copper
atoms. The X-band EPR spectrum of complex 3 is similar to com-
plex 1, and shows a typical axial signal, supporting the absence
of magnetic coupling. The electrospray ionization mass spectra
between the copper and the pyridyl-amidate chelate, while in the
0
binuclear 3, (LPhO
)
2ꢀ forms a six-membered ring between the cop-
0
per and the pyridyl-amidate chelate, since (LPhO
)
2ꢀcontains an
additional carbon atom in the linkage between the pyridyl ring
and the amide. In addition, the coordination mode of the copper
is different, one is four-coordinate, and the other is five-coordinate.
All of these differences illustrate the effects of ligand flexibility on
the nuclearity and the coordination geometry in copper complexes
with these ligands.
Acknowledgments
This work was supported by the National Science Foundation
(NSF CHE-0616941). Additionally, we thank the NSF for the pur-
chase of a CCD-equipped X-ray diffractometer (CHE-0130835).
Appendix A. Supplementary material
CCDC 725451, 725452, and 725453 contain the supplementary
crystallographic data for 1, 2, and 3, respectively. These data can be
obtained free of charge from The Cambridge Crystallographic Data
0
thesis and characterization details for HLPhOH, HLPhOH , and 1–3.
Supplementary data associated with this article can be found, in
(ESI-MS) of 3 reveals the presence of the compound in solution,
0
with a peak at m/z = 607.87 corresponding to {[Cu2(LPhO )2] + H}+
without the coordinated methanol molecules.
References
[1] Y. Xie, H. Jiang, A.S.C. Chan, Q. Liu, X. Xu, C. Du, Y. Zhu, Inorg. Chim. Acta 333
(2002) 138.
[2] J. Sletten, A. Sørensen, M. Julve, Y. Journaux, Inorg. Chem. 29 (1990) 5054.
[3] X.S. Tan, Y. Fujii, R. Nukada, M. Mikuriya, Y. Nakano, J. Chem. Soc., Dalton Trans.
(1999) 2415.
[4] L. Yang, D.R. Powell, E.L. Klein, A. Grohmann, R.P. Houser, Inorg. Chem. 46
(2007) 6831.
[5] L. Yang, D.R. Powell, R.P. Houser, Dalton Trans. (2007) 955.
[6] U. Pal Chaudhuri, L.R. Whiteaker, A. Mondal, E.L. Klein, D.R. Powell, R.P. Houser,
Inorg. Chim. Acta 360 (2007) 3610.
[7] L. Yang, R.P. Houser, Inorg. Chem. 45 (2006) 9416.
[8] U. Pal Chaudhuri, L.R. Whiteaker, L. Yang, R.P. Houser, Dalton Trans. (2006)
1902.
[9] A. Mondal, Y. Li, M.A. Khan, J.H. Ross, R.P. Houser, Inorg. Chem. 43 (2004) 7075.
[10] E.L. Klein, M.A. Khan, R.P. Houser, Inorg. Chem. 43 (2004) 7272.
[11] L.R. Whiteaker, U. Pal Chaudhuri, D.R. Powell, R.P. Houser, Acta Crystallogr. E
E62 (2006) o3339.
[12] L.R. Whiteaker, U. Pal Chaudhuri, D.R. Powell, R.P. Houser, Acta Crystallogr. E
E62 (2006) o3337.
[13] See Supplementary Information for full synthetic and characterization details.
[14] [Cu4(LPhO)4] (1). A solution of Cu(OTf)2 (0.0905 g, 0.250 mmol) in methanol
was added to a solution of HLPhOH (0.114 g, 0.500 mmol) and triethylamine
(0.147 ml, 1.00 mmol) in methanol, followed by vapor diffusion of diethyl
ether into the solution (0.0456 g, 62.9% yield). Anal. Calcd. for
C52H40Cu4N8O8ꢁ2CH3OH: C, 53.0; H, 4.0; N, 9.2. Found: C, 52.9; H, 4.4; N, 9.4.
FTIR (KBr): 3750, 3435, 1772, 1733, 1695, 1653 (mC=O), 1599, 1587, 1548, 1444,
1383, 1215, 1162, 1097, 756, 619, 589, 516, 464 cmꢀ1. UV–vis (CH3OH) [kmax
,
nm (e
, molꢀ1 cmꢀ1)]: 390 (1400), 611 (400). ESI-MS (CH3OH): m/z = 601.98,
{[Cu4(LPhO)4] + 2Na}2+; m/z = 1181.06, {[Cu4(LPhO)4] + Na}+. EPR (CH3OH, 77 K,
9.455 GHz, 0.25 mW, mod. amp. 1 G): g\ = 2.04, g|| = 2.246, A|| = 184 G.
Magnetic moment (Evans method, 293 K, DMSO-d6): 1.813 BM/Cu. Crystal
data: C54H48Cu4N8O10, Mr = 1223.16 g molꢀ1, monoclinic, space group C2/c,
a = 24.617(5) Å, b = 17.336(4) Å, c = 13.445(3) Å,
a
=
,
c
= 90°, b = 120.791(5)°,
V = 4929.0(19) Z = 4,
Å3, calcd = 1.648 g cmꢀ3
q
k(MoK ) = 0.71073 Å,
a
Fig. 3. Representation of the X-ray crystal structure of 3 with thermal ellipsoids at
the 50% probability level. Selected bond lengths (Å) and angles (°): Cu1–N10,
1.9362(16); Cu1–N14, 1.9954(17); Cu1–O1, 1.9530(13); Cu1–O10, 1.9831(13); Cu1–
O19, 2.3476(14); N10–Cu1–N14, 93.50(7); N10 –Cu1–O19, 86.96(5); O1–Cu1–N14,
173.74(6); N14 –Cu1–O19, 88.21(6); Cu1-O1-Cu1A, 102.13(6).
T = 100(2) K, crystal dimensions 0.27 ꢂ 0.16 ꢂ 0.14 mm,
l(MoK ) = 1.733
a
mmꢀ1
,
h = 1.92–26.00°, 19250 measured reflections, 4855 independent
reflections (Rint = 0.0261), R1 = 0.0260, wR2 = 0.0715, GOF = 1.011, 325
parameters, final difference map within 0.398 and ꢀ0.303 eÅꢀ3
.
[15] C. Janiak, J. Chem. Soc. Dalton Trans. (2000) 3885.