Abstract The synthesis and X-ray crystal structure of a ten-coordinate cerium(III) nitrate complex of 2,6-bis[2-formylphenoxymethyl]-pyridine is reported

Cecilia O Rodriguez De Barbarin

David E Fenton

Gareth J Humber

Neil A Bailey

Yuh-Shan Ho

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ELSEVIER 
Inorgan ica  Chimica  Ac ta  232 (1995) 227-230 
The 
Note 
synthesis and crystal structure of a cerium(III) complex of 
2,6-bis [2-formylphenoxymethyl]pyridine 
Neil A. Bailey, Cecilia O. Rodriguez de Barbarin 1, David E. Fenton *, 
Yuh-Shan Ho, Gareth J. Humber 
Department of Chemistry, Dainton Building, The University of Sheffield, Sheffield $3 7HF, UK 
Received 4 July 1994; revised 2 November 1994 
Abstract  
T h e  synthesis  and  X-ray crystal s t ruc ture  of  a t en-coord ina te  ce r ium(I I I )  n i t ra te  complex of 2,6-bis[2-formylphenoxymethyl]-  
pyr idine  is r epor ted .  
Keywords: Crystal structures; Cerium complexes; Macroeyclic ligand complexes 
1. Introduction 
Eighteen-membered pyridinyl-derived NaOa-Schiff 
base macrocycles have been prepared by lanthanide- 
templated cyclocondensation reactions [1]. The synthesis 
of the 20-membered macrocycle OpynNenOen, derived 
from bis(2-aminoethyl)ether and 2,6-bis[2-formylphen- 
oxymethyl]pyridine (Opyn), has been achieved both by 
non-template (Scheme 1) and templated reactions in- 
volving barium and lead(II) [2]. In contrast the ap- 
plication of template methodology to this reaction using 
hydrated lanthanide nitrates in methanol was found to 
be unsuccessful in promoting the cyclocondensation and 
MeOH 
+ 
refluxed 
/ N / - X  
H2N 0 NH 2 
Scheme 1. 
/A 
N N 
 o.j 
OpynNenOen 
* Corresponding author. 
1On leave from: Faculdad de Ciencias Quimicas, Universidad 
Aut6noma de Nuevo Le6n, Monterrey, Mexico. 
0020-1693/95/$09.50 © 1995 Elsevier Science S.A. All rights reserved 
SSDI 0020-1693(94)04371-2  
generally yielded intractable materials. This may be 
related to the smaller radius of the cerium cation)(1.39 
~ )  compared with the radii of lead(II) (1.54 and 
barium (1.66/~) [3]. 
2. Results and discussion 
The reaction of cerium(III) nitrate with the macro- 
cycle OpynNenOen in a 1:1 ratio in methanol yielded 
a crystalline product. There was an absence of bands 
characteristic of imine groups from the starting material 
in the IR spectrum of this product (4000-600 cm-l;  
KBr disc) but strong absorptions at 1659 and 1655 
cm- 1, indicating the presence of carbonyl groups, were 
present. In addition there are bands at 3445, 1639 and 
834 cm -1 suggestive of water molecules coordinated 
to the metal. The FAB mass spectrum of the complex 
gave a parent peak at 611 a.m.u, corresponding to 
[Ce(Opyn)(NO3)2] + with a further peak at 348 a.m.u. 
corresponding to [(Opyn)H] +, reinforcing the sugges- 
tion of an acyclic ligand. The above information together 
with microanalytical data led to the formulation of the 
product as [Ce(Opyn)2](NO3)3-2H20 which had been 
formed by a retro-Schiff base reaction, the water being 
provided either from the solvent methanol or from the 
hydrated cerium salt, with accompanying cerium(Ill) 
complexation (Scheme 2). The 1H NMR spectra for 
228 N.A. Bailey et al. / Inorganica Chimica Acta 232 (1995) 227-230 
Q o  ~ + Ce(NO3)3.6H20 
N N 
IMP°" 
Scheme 2. 
Table 1 
tH NMR data (ppm) for the ligand (Opyn) and the complex 
[Ce(Opyn)2](NO3)3.2H20 
H1 
H4 Ha H ~ ~ . ]  
H s ~ O  0 
"'- T "I =° °fl-  
H 7 H8 
Ligand signal Complex signal 
H~ 7.81m, 3H 7.93t, 1H 
H2 7.81 7.79d, 2H 
H 3 5.34s, 4H 5.37s, 4H 
H4 7.21d, 2H 7.22d, 2H 
H6 7.08t, 2H 7.10t, 2H 
Hs 7.60m, 4H 7.62m, 4H 
H7 7.60 7.62 
Ha 10.55s, 2H 10.52s, 2H 
the free ligand (Opyn) and the complex 
[Ce(Opyn)2](NO3)3.2H20 are very similar (Table 1) 
suggesting that the two-fold symmetry of the ligand is 
retained in solution. 
The acyclic nature of the complex was confirmed by 
X-ray structure analysis. The molecular structure is 
illustrated in Fig. 1 with bonds and angles presented 
in Table 2. The cerium is ten-coordinated, the bonding 
being provided by oxygen atoms from three symmet- 
rically bidentate nitrate anions together with two oxygen 
atoms from the water molecules and one carbonyl oxygen 
from each Opyn ligand. The second carbonyl oxygen 
atom in each ligand molecule is not coordinated. All 
the bond lengths were significantly shorter than the 
sum of the van der Waals radius of oxygen and ten- 
C 
G( 
Ol0 
b 
N3 
po8 
Ol c3 
~ c2~--oS 4 
b- 02%" 
el C ~  ~C8 
C11 ~ . ~ )  N1 
C12 C~,~ C14 
C21 O3% C15 
~ . ~ ~ 1 6  
C18 
Fig. 1. The crystal structure of [Ce(Opyn)2](NOa)3.2H20 showing 
one component of the disordered nitrate. 
coordinate Ce(III) (2.790 /~). Although structurally 
characterized ten-coordinate lanthanide complexes are 
well known, structural information for tri(bidentate 
nitrato)lanthanide complexes with an additional four 
monodentate oxygen ligands is limited [4]. In the struc- 
tures of Ln(NO3)3.4dmso the average Ln-O distances 
to the dmso are shorter than those to the nitrate anions, 
La (2.475 versus 2.653 ~ )  and Nd (2.385 versus 2.661 
/k) [5]. In [Ce(Opyn)2](NOa)3.2H20 the bond lengths 
for Ce-Ocarbony j a re  longer (2.614(9)/~) than those for 
Ce-Ow,,e, and Ce-ONo3 for which the average value 
is 2.538(10) /~. 
The coordinated water molecules are involved in 
hydrogen bonding with a pyridyl nitrogen, and with the 
non-coordinated benzaldehyde oxygen atoms of differ- 
ent symmetry related molecules (O(l l) . . .N(1) a 2.856 
/~, O(11)...O(4) b 2.832/~; with symmetry operations: 
a x, - y ,  0.5 +z; b 0.5 +x, - 0 .5-y,  0.5 +z). Inversion 
related pairs of N... O hydrogen bonds link molecules 
in chains parallel to the crystallographic c-axis: inversion 
related pairs of O...  O hydrogen bonds cross-link these 
chains to form a three-dimensional network. 
3. Experimental 
3.1. Reaction of OpynNenOen with cerium(Ill) nitrate 
A solution of OpynNenOen [2] (1 mmol) and cer- 
ium(III) nitrate (1 mmol) in methanol (100 cm 3) was 
refluxed for ~ 2 h then allowed to cool to room tem- 
perature. It was left to stand undisturbed in order to 
slowly remove the solvent. The product was recrystal- 
lized from acetonitrile to give crystals suitable for X- 
ray analysis. The crystalline product, [Ce(Opyn)2]- 
(NO3)3-2H20, was isolated in 19% yield. Anal. 
Found: C, 47.93; H, 3.54; N, 6.64. Calc. for 
N,4. Bailey et aL / lnorganica Chimica Acta 232 (1995) 227-230 
Table 2 
Selected bond lengths (A) and angles (°) for [Ce(Opyn)2](NO3) 3.2H20 
229 
Bond lengths 
Ce(1)-O(1) 2.614(9) Ce(1)-O(5) 
Ce(1)-O(6) 2.577(10) Ce(1)-O(ll) 
Ce(1)-O(8) 2.512(10) Ce(1)-O(9) 
O(11)...N(I) a 2.856 H(OllB)...N(1)" 
O(11)...0(4) b 2.832 H(O11A)...(04) b 
Bond angles 
O(1)--Ce(1)-O(5) 63.1(3) O(1)-Ce(1)-O(6) 
O(5)-Ce(1)-O(6) 48.5(3) O(1)-Ce(1)-O(11) 
O(5)-Ce(1)-O(11) 68.9(3) O(6)-Ce(1)-O(11) 
O(1)-Ce(1)-O(8) 70.9(4) O(5)--Ce(1)-O(8) 
O(6)-Ce(1)-O(8) 132.9(3) O(11)-Ce(1)-O(8) 
O(1)-Ce(1)-O(9) 116.1(4) O(5)-Ce(1)-O(9) 
O(6)-Ce(1)-O(9) 131.5(4) O(11)-Ce(1)-O(9) 
O(8)-Ce(1)-O(9) 49.2(2) O(1)-Ce(1)-O(1A) 
O(5)--Ce(1)-O(1A) 113.6(3) O(6)-Ce(1)-O(1A) 
O(ll)-Ce(1)-O(1A) 69.6(3) O(8)-Ce(1)-O(1A) 
O(9)-Ce(1)-O(1A) 70.6(4) O(1)---Ce(1)-O(5A) 
O(5)-Ce(1)-O(5A) 125.4(5) O(6)-Ce(1)-O(5A) 
O(ll)-Ce(1)-O(5A) 132.3(3) O(8)-Ce(1)-O(5A) 
O(9)-Ce(1)-O(5A) 101.4(4) O(5)--(~e(1)-O(6A) 
O(1)-Ce(1)-O(6A) 70.9(3) O(11)-Ce(1)-O(6A) 
O(6)-Ce(1)-O(6A) 74.6(5) O(9)-Ce(1)-O(6A) 
O(8)-Ce(1)-O(6A) 137.4(4) O(5)-Ce(1)--O(11A) 
O(1)--Ce(1)-O(11A) 69.6(3) O(11)--Ce(1)--O(11A) 
O(6)-Ce(1)-O(11A) 147.0(3) O(9)--Ce(1)--O(11A) 
O(8)-Ce(1)-O(11A) 76.9(3) Ce(1)-O(1)--C(1) 
2.547(10) 
2.534(8) 
2.520(10) 
1.853 
1.832 
103.6(3) 
112.8(3) 
72.7(3) 
92.9(4) 
67.7(3) 
130.1(3) 
67.0(3) 
173.3(4) 
70.9(3) 
115.5(4) 
113.6(3) 
86.2(3) 
139.9(3) 
86.2(3) 
147.0(3) 
143.1(3) 
132.3(3) 
140.2(5) 
76.4(3) 
127.6(8) 
Symmetry related atoms by the following operations: ~x, -y, 0.5 +z; b 0.5 +x, -0.5-y, 0.5 +z. 
C4zH34NsO17Ce.2HEO: C, 47.73; H, 3.62; N, 6.63%. 
The 1H NMR spectral data (250 MHz; CD3CN) for 
the complex [Ce(Opyn)2](NO3)3.2H/O together with 
that of the free Opyn ligand are shown in Table 1. 
3.2. Crystal structure 
Crystal data for Ce(C21H17NO4)z(NO3)3-2H20: 
M=1056.85, crystallized from acetonitrile as clear 
prisms, crystal dimensions 0.40 × 0.32 × 0.18 mm; 
monoclinic, a = 20.708(8), b = 9.212(5), c = 22.722(9)/~,, 
/3= 103.81(3) °, U=  4209(3)/~3, Z = 4, Dc = 1.67 g cm -3, 
space group C2/c (~22h, NO. 15), MO Ka radiation 
(A = 0.71069/~),/~ (Mo Ka) = 11.82 cm-1,  F(000) = 2140. 
Three  dimensional, room temperature  X-ray data 
were collected in the range 3.5 < 20 < 50.0 ° on a Nicolet 
R3 diffractometer by the to-scan method. The 2470 
independent reflections (of 4107 measured) for which 
IF[/tr([F{) > 3.0 were corrected for Lorentz  and polari- 
zation effects, and for absorption by analysis of nine 
azimuthal scans (minimum and maximum transmission 
coefficients of 0.427 and 0.509). The structure was 
solved by Patterson and Fourier  techniques and refined 
by blocked cascade least-squares methods. One nitrate 
was found to be disordered across the C2 axis, and the 
anion was modelled with 50% occupancies for nitrogen 
and three oxygens. Hydrogen atoms were included in 
calculated positions, or along intermolecular hydrogen 
bonds, and refined in riding mode. Refinement con- 
verged at a finalR = 0.0898 (Rw = 0.0794, 295 parameters,  
mean and maximum ~/tr 0.003, 0.015), with allowance 
for the thermal anisotropy of all non-hydrogen atoms, 
with the exception of the atoms of the half occupancy 
nitrate. Minimum and maximum final electron density: 
-2 .58  and +2.92 e A, -3 close to the cerium atom. A 
weighting scheme w - 1 =  [o~2(F)+0.00050F 2] was used 
in the latter stages of refinement. Complex scattering 
factors were taken from Ref. [6] and from the program 
package S H E L X T L  [7] as implemented on a Data 
General  DG30 computer.  
4. Supplementary material 
Tables of bond lengths and angles, anisotropic thermal 
vibrational parameters and atomic coordinates, all with 
e.s.d.s, hydrogen atom position parameters, observed 
structure amplitudes and calculated structure factors 
are available from the authors on request. 
Acknowledgements 
We thank the SERC and Royal Society for funds 
towards the purchase of the diffractometer; we also 
230 N.A. Bailey et al. / Inorganica Chimica Acta 232 (1995) 227-230 
thank the Universidad Auton6ma de Nuevo Leon for 
granting leave of absence to C.O.R.deB. 
References 
[1] A.M. Arif, C.J. Gray, F.A. Hart and M.B. Hursthouse, Inovg. 
Chim. Acta, 109 (1985) 179; R. Bandin, R. Bastida, A. de Bias, 
P. Castro, D.E. Fenton, A. Macias, A. Rodriguez and T. 
Rodriguez, J. Chem. Soc., Dalton Trans., (1994) 1185. 
[2] H. Adams, N.A. Bailey, R. Bastida, D.E. Fenton, Y-S. Ho and 
P.D. Hempstead, J. Chem. Res. S, (1992) 190. 
[3] D.E. Fenton and P.A. Vigato, Chem. Soc. Rev., 17 (1988) 69. 
[4] G.J. Palenik, in S.P. Sinha (ed.), Systematics and the Properties 
of  the Lanthanides, NATO-ASI Series C109, Reidel, Dordrecht, 
Netherlands, 1983, Ch. 5. 
[5] K.K. Bhandary and H. Manohar, Acta Crystallogr., Sect. B, 29 
(1973) 1093; L.A. Aslanov, L.I. Soleva, M.A. Porai-Koshits and 
S.S. Goukhberg, Zh. Strukt. Khim., 13 (1972) 655. 
[6] International Tables for X-Ray Crystallography, Vol. 4, Kynoch, 
Birmingham, UK, 1974. 
[7] G.M. Sheldrick, SHELXTL, an integrated system for solving, 
refining and displaying crystal structures from diffraction data 
(Revision 5.1), University of G6ttingen, Germany, 1985. 


The Note synthesis and crystal structure of a cerium(III) complex of 2,6-bis [2-formylphenoxymethyl]pyridine

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The Note synthesis and crystal structure of a cerium(III) complex of 2,6-bis [2-formylphenoxymethyl]pyridine

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