Coaggregation of paramagnetic d- and f-block metal ions with a podand-framework amine phenol ligand

Article abstract of DOI:10.1021/ic991171b

This report covers initial studies in the coaggregation of nickel (Ni²⁺) and lanthanide (Ln³⁺) metal ions to form complexes with interesting structural and magnetic properties. The tripodal amine phenol ligand H₃tam (1,1,1-tris(((2-hydroxybenzyl)amino)methyl)ethane) is shown to be particularly accommodating with respect to the geometric constraints of both transition and lanthanide metal ions, forming isolable complexes with both of these ion types. In the solid-state structure of [Ni(H₂tam)(CH₃CN)]PF₆·2.5CH₃CN·0.5CH₃OH (1), the Ni(II) center has a distorted octahedral geometry, with an N₃O₂ donor set from the [H₂tam]^- ligand and a coordinated solvent (acetonitrile) occupying the sixth site. The reaction of stoichiometric amounts of H₃tam with the Ni(II) ion in the presence of lanthanide(III) ions provides [LnNi₂(tam)₂]⁺ cationic complexes which contain coaggregated metal ions. These complexes are isolable and have been characterized by a variety of analytical techniques, with mass spectrometry proving to be particularly diagnostic. The solid-state structures of [LaNi₂(tam)₂(CH₃OH)( 1/2 )-(CH₃CH₂OH)( 1/2 )(H₂O)]Cl0₄·0.5CH₃OH·0.5CH₃CH ₂OH·4H₂O (2), [DyNi₂(tam)₂(CH₃OH)(H₂O)]ClO₄·CH₃H·H₂O (6), and [YbNi₂(tam)₂(H₂O)]ClO₄·2.58H₂O (9) have been determined. Each complex contains two octahedral Ni(II) ions, each of which is encapsulated by the ligand tam^3- in an N₃O₃ coordination sphere; each [Ni(tam)]^- unit caps the lanthanide(III) ion via bridging phenoxy oxygen donor atoms. In 2, La³⁺ is eight-coordinated, while in 6, Dy(III) is seven- (to 'weakly eight-') coordinated, and Yb(III) in 9 has a six-coordination environment. The complexes are symmetrically different, 2 possessing C₂ symmetry and 6 and 9 having C₁ symmetry. Magnetic studies of 2, 6, and 9 indicate that antiferromagnetic exchange coupling between the Ni(II) and Ln(III) ions increases with decreasing ionic radius of Ln(III).

Full text of DOI:10.1021/ic991171b

508
Inorg. Chem. 2000, 39, 508-516
Coaggregation of Paramagnetic d- and f-Block Metal Ions with a Podand-Framework
Amine Phenol Ligand†
Zhiqiang Xu,‡ Paul W. Read,‡ David E. Hibbs,§ Michael B. Hursthouse,§ K. M. Abdul Malik,§
Brian O. Patrick,‡ Steven J. Rettig,‡ Mehran Seid,‡ David A. Summers,‡ Maren Pink,|
Robert C. Thompson,‡ and Chris Orvig*,‡
Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia,
2036 Main Mall, Vancouver, BC V6T 1Z1, Canada, Department of Chemistry, University of Wales,
Cardiff, P.O. Box 912, Cardiff CF1 3TB, U.K., and X-ray Crystallographic Laboratory,
University of Minnesota, Minneapolis, Minnesota 55455
ReceiVed October 4, 1999
This report covers initial studies in the coaggregation of nickel (Ni2+) and lanthanide (Ln3+) metal ions to form
complexes with interesting structural and magnetic properties. The tripodal amine phenol ligand H3tam (1,1,1-
tris(((2-hydroxybenzyl)amino)methyl)ethane) is shown to be particularly accommodating with respect to the
geometric constraints of both transition and lanthanide metal ions, forming isolable complexes with both of these
ion types. In the solid-state structure of [Ni(H2tam)(CH3CN)]PF6‚2.5CH3CN‚0.5CH3OH (1), the Ni(II) center has
a distorted octahedral geometry, with an N3O2 donor set from the [H2tam]- ligand and a coordinated solvent
(acetonitrile) occupying the sixth site. The reaction of stoichiometric amounts of H3tam with the Ni(II) ion in the
presence of lanthanide(III) ions provides [LnNi2(tam)2]+ cationic complexes which contain coaggregated metal
ions. These complexes are isolable and have been characterized by a variety of analytical techniques, with mass
spectrometry proving to be particularly diagnostic. The solid-state structures of [LaNi2(tam)2(CH3OH)1/2
-
(CH3CH2OH)1/2(H2O)]ClO4‚0.5CH3OH‚0.5CH3CH2OH‚4H2O (2), [DyNi2(tam)2(CH3OH)(H2O)]ClO4‚CH3OH‚
H2O (6), and [YbNi2(tam)2(H2O)]ClO4‚2.58H2O (9) have been determined. Each complex contains two octahedral
Ni(II) ions, each of which is encapsulated by the ligand tam3- in an N3O3 coordination sphere; each [Ni(tam)]-
unit caps the lanthanide(III) ion via bridging phenoxy oxygen donor atoms. In 2, La3+ is eight-coordinated, while
in 6, Dy(III) is seven- (to “weakly eight-”) coordinated, and Yb(III) in 9 has a six-coordination environment. The
complexes are symmetrically different, 2 possessing C2 symmetry and 6 and 9 having C1 symmetry. Magnetic
studies of 2, 6, and 9 indicate that antiferromagnetic exchange coupling between the Ni(II) and Ln(III) ions
increases with decreasing ionic radius of Ln(III).
Introduction
review articles.7 These writings cover in detail the magnetic
properties of complexes with mixed Cu(II) and lanthanide(III)
Metal complexes with high coordination numbers have
received much attention for many years.1,2 More recently, a
particular area of research focus has been the chemistry of
multidentate ligands with lanthanide(III) ions. This is due in
part to the wide variety of uses that lanthanide(III) ions find in
today’s technologies; because of their magnetic and physical
properties, rare earth elements are utilized as magnetic resonance
imaging (MRI) contrast agents,3,4 as ester hydrolysis reagents,5
and in powerful magnets.6 The magnetic properties of f-block
elements is an area of research that is generating much interest
and has been extensively reviewed by Kahn in a book and two
ions and hence their behavior is well studied and understood.7
The magnetic properties of mixed Ni(II) and Ln(III) ion
complexes, however, have not been previously studied in detail
and have only recently been of interest.8
Of late, we have been investigating the reactions of amine
phenol ligands with group 13 and lanthanide(III) ions in both
aqueous and nonaqueous media.9 During the course of this prior
work, five different coordination modes of amine phenol ligands
with lanthanide ions were structurally characterized (see Chart
1). This work has now been extrapolated to the coaggregation
of d- and f-block metal ions in solution and in the solid state
through encapsulation of a divalent transition metal into the
bicapped structure. Amine phenol ligands are hydrolytically
stable and are geometrically more flexible than their Schiff base
analogues. Multidentate ligands that can incorporate two or more
metal atoms are useful in studying the magnetic interactions
between metal ions. Homo- and heteropolynuclear complexes
* To whom correspondence should be addressed. Tel: 604-822-4449.
Fax: 604-822-2847. E-mail: orvig@chem.ubc.ca.
† This paper is dedicated to our dear friend and sadly missed colleague
Steven J. Rettig.
‡ University of British Columbia.
§ University of Wales.
| University of Minnesota.
(1) Drew, M. G. B. Prog. Inorg. Chem. 1977, 23, 67.
(2) Drew, M. G. B. Coord. Chem. ReV. 1977, 24, 179.
(3) Watson, A. D. J. Alloys Compd. 1994, 207/208, 14.
(4) Kumar, K.; Jin, T.; Wang, X.; Desreux, J. F.; Tweedle, M. F. Inorg.
Chem. 1994, 433, 3823.
(7) (a) Kahn, O. Struct. Bonding (Berlin) 1987, 68, 89. (b) Kahn, O. AdV.
Inorg. Chem. 1995, 43, 179. (c) Kahn, O. Molecular Magnetism;
VCH: New York, 1993.
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(8) (a) Lisowski, J.; Starynowicz, P. Inorg. Chem. 1999, 38, 1351. (b)
Knoeppel, D. W.; Liu, J.; Meyers, E. A.; Shore, S. G. Inorg. Chem.
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10.1021/ic991171b CCC: $19.00 © 2000 American Chemical Society
Published on Web 01/15/2000

Coaggregation of d- and f-Block Metal Ions
Inorganic Chemistry, Vol. 39, No. 3, 2000 509
Chart 1
The choice of H3tam as ligand in this study was not a
fortuitous one, since a flexible ligand with intrinsic selectivity
would favor the isolation of coaggregated metal ion complexes.
The ligand H3tam is geometrically less demanding than the
Schiff base analogue saltame (1,1,1-tris(((2-hydroxybenzyl)-
imino)methyl)ethane) because of the greater flexibility of the
amino linkages in the amine phenol ligand. Selectivity is
inherent within H3tam, since the ligand contains (formally) both
hard and soft donor atoms. The harder phenoxy O donors will
bond preferentially to the hard Ln(III) ion in the absence of
external factors. Transition metal ions, which are softer than
Ln(III) ions, may bond preferentially to softer amine functions.
Experimental Section
Materials. AgPF6 and NiCl2‚6H2O were purchased from Aldrich.
Hydrated lanthanide(III) perchlorates were obtained from Alfa either
as the solid or as 50% (w/w) solutions in water, which were evaporated
to dryness. Triethylamine was purchased from Fisher and was used as
received. NMR solvents were purchased from Aldrich and were used
as received. Ni(ClO4)2‚6H2O was prepared from the corresponding
carbonates by dissolution in perchloric acid and H3tam was prepared
according to our literature procedure.14 Methanol was dried prior to
use over molecular sieves.
Caution! Perchlorate salts are potentially explosiVe and should be
handled with extreme care and used only in small quantities.13
Physical Measurements. 1H NMR spectra (200 and 300 MHz) were
recorded on Bruker AC-200E and Varian XL-300 spectrometers,
respectively, and were referenced internally to residual solvent hydro-
gens. Mass spectra were obtained with a Kratos Concept II H32Q (Cs+,
LSIMS) instrument. Infrared spectra were recorded as KBr disks in
the range 4000-400 cm-1 on a Mattson Galaxy Series FTIR-5000
spectrophotometer and were referenced to polystyrene (1601.3 cm-1).
Analyses of C, H, and N were performed by Mr. Peter Borda at the
University of British Columbia. The room-temperature magnetic
susceptibilities were measured on a Johnson Matthey MSB-1 balance
(solid state), and variable-temperature magnetic susceptibility measure-
ments were performed on a Quantum Design SQUID magnetometer
for dried powder samples (2-300 K, 10 kG). Diamagnetic corrections
were applied to the data on the basis of Pascal’s constants.
Syntheses of the Complexes. (a) [Ni(H2tam)]PF6 (1). To a solution
of NiCl2‚6H2O (100 mg, 0.41 mmol) in methanol (5 mL) was added
AgPF6 (212 mg, 0.84 mmol). The solution was allowed to stir for 10
min and was then clarified by filtration. To the filtrate was added H3-
tam (183 mg, 0.42 mmol) in methanol (5 mL), and a purple color
developed immediately. The solution was evaporated to ca. 2 mL, and
the concentrate was allowed to stand at room temperature, whereupon
purple plates deposited. The crystals were washed with a small amount
of diethyl ether and dried in air. X-ray-quality crystals were obtained
containing rare earth metals are of great interest because of their
unique physicochemical properties10 and may even be potentially
useful as models of metalloenzymes and in applications to
catalysis. Schiff base ligands have been used for many years to
isolate polynuclear materials where the compositions and
topologies of the resultant complexes can be easily controlled.11
A systematic study has been undertaken in order to investigate
the magnetophysical properties of mixed Ni2Ln and Cu2Ln
complexes. In this paper, we present the syntheses and
characterizations of a series of d- and d-f-block metal
complexes of the potentially hexadentate amine phenol ligand
H3tam12 with Ni2+ and Ln3+ ions.
(11) (a) Fenton, D. E.; Okawa, H. In PerspectiVes in Coordination
Chemistry; Williams, A. F., Floriani, C., Merbach, A. E., Eds.; VCH:
Weinheim, Germany, 1992; p 203. (b) McKee, V. AdV. Inorg. Chem.
1993, 40, 323. (c) Nanda, K. K.; Thompson, L. K.; Brisdon, J. N.;
Nag, K. J. Chem. Soc., Chem. Commun. 1994, 1337. (d) Nanda, K.
K.; Das, R.; Thompson, L. K.; Vewnkatsubrammanian, K.; Paul, P.;
Nag, K. Inorg. Chem. 1994, 33, 1188. (e) Pilkington, N. H.; Robson,
R. Aust. J. Chem. 1970, 23, 2225. (f) Atkins, A. J.; Black, D.; Blake,
A. J.; Marin-Becerra, A.; Parsons, S.; Ruiz-Ramirez, L.; Schroder,
M. J. Chem. Soc., Chem. Commun. 1996, 457. (g) Daolio, S.; Facchin,
B.; Pagura, C.; Guerriero, P.; Sitran, S.; Vigato, P. A. Inorg. Chim.
Acta 1990, 178, 131. (h) Kahwa, I. A.; Selbin, J.; Hsieh, T. C.-Y.;
Laine, R. A. Inorg. Chim. Acta, 1986, 118, 179. (i) Kahwa, I. A.;
Fronczek, F. R.; Selbin, J. Inorg. Chim. Acta 1987, 126, 227. (j)
Kahwa, I. A.; Fronczek, F. R.; Selbin, J. Inorg. Chim. Acta 1988,
148, 273. (k) Guerriero, P.; Tamburini, S.; Vigato, P. A.; Benelli, C.
Inorg. Chim. Acta 1991, 189, 19.
(9) (a) Caravan, P.; Orvig, C. Inorg. Chem. 1997, 36, 236. (b) Lowe, M.
P.; Rettig, S. J.; Orvig, C. J. Am. Chem. Soc. 1996, 118, 10446. (c)
Caravan, P.; Mehrkhodavandi, P.; Orvig, C. Inorg. Chem. 1997, 36,
1316. (d) Caravan, P.; Rettig, S. J.; Orvig, C. Inorg. Chem. 1997, 36,
1306. (e) Lowe, M. P.; Caravan, P.; Rettig, S. J.; Orvig, C. Inorg.
Chem. 1998, 37, 1637. (f) Wong, E.; Caravan, P.; Liu, S.; Rettig, S.
J.; Orvig, C. Inorg. Chem. 1996, 35, 715. (g) Caravan, P.; Hedlund,
T.; Liu, S.; Sjo¨berg, S.; Orvig, C. J. Am. Chem. Soc. 1995, 117, 11230.
(h) Wong, E.; Liu, S.; Rettig, S. J.; Orvig, C. Inorg. Chem. 1995, 34,
3057. (i) Yang, L.-W.; Liu, S.; Wong, E.; Rettig, S. J.; Orvig, C. Inorg.
Chem. 1995, 34, 2164. (j) Wong, E.; Liu, S.; Lu¨gger, T.; Hahn, F. E.;
Orvig, C. Inorg. Chem. 1995, 34, 93. (k) Liu, S.; Wang, L.-W.; Rettig,
S. J.; Orvig, C. Inorg. Chem. 1993, 32, 2773. (l) Liu, S.; Gelmini, L.;
Rettig, S. J.; Thompson, R. C.; Orvig, C. J. Am. Chem. Soc. 1992,
114, 6081. (m) Berg, D. J.; Rettig, S. J.; Orvig, C. J. Am. Chem. Soc.
1991, 113, 2528. (n) Smith, A.; Rettig, S. J.; Orvig, C. Inorg. Chem.
1988, 27, 3929.
(12) H3tam ) 1,1,1-tris(((2-hydroxybenzy)amino)methyl)ethane. The H3
(10) (a) Guerriero, P.; Vigato, P. A.; Bunzli, J.-C. G.; Moret, E. J. Chem.
Soc., Dalton Trans. 1990, 647. (b) Casellato, U.; Guerriero, P.;
Tamburini, S.; Vigato, P. A.; Graziani, R. J. Chem. Soc., Dalton Trans.
1990, 1533. (c) Guerriero, P.; Sitran, S.; Vigato, P. A.; Marega, C.;
Zametti, R. Inorg. Chim. Acta 1990, 171, 103.
term refers to the three ionizable phenolic protons.
(13) For further information, see: Wolsey, W. C. J. Chem. Educ. 1973,
50, A335.
(14) Liu, S.; Wong, E.; Karunaratne, V.; Rettig, S. J.; Orvig, C. Inorg.
Chem. 1993, 32, 1756.

510 Inorganic Chemistry, Vol. 39, No. 3, 2000
Xu et al.
Table 1. [LnNi2(tam)2]ClO4‚xH2O Complexes (2-9) and Their Analytical Data
complex
% C
% H
% N
µ
eff/RT, µB
m/z of [LnNi2(tam)2]+
[LaNi2(tam)2]ClO4‚3H2O (2)
49.00a
(48.99)b
50.56
(50.33)
50.20
(50.20)
48.12
(48.30)
47.79
(48.10)
47.26
(48.01)
47.43
(47.92)
47.57
(47.71)
5.24
(5.22)
5.13
(5.04)
5.17
(5.02)
5.02
(5.14)
4.99
(5.12)
5.36
(5.11)
5.26
(5.10)
5.37
(5.08)
6.70
(6.59)
6.84
(6.77)
6.73
(6.75)
6.42
(6.50)
6.42
(6.47)
6.54
(6.46)
6.63
(6.45)
6.59
(6.42)
4.05c
(4.00)d
6.46e
1119
1121
1126
1140
1144
1145
1148
1154
[PrNi2(tam)2]ClO4‚H2O (3)
[NdNi2(tam)2]ClO4‚H2O (4)
[GdNi2(tam)2]ClO4‚3H2O (5)
[DyNi2(tam)2]ClO4‚3H2O (6)
[HoNi2(tam)2]ClO4‚3H2O (7)
[ErNi2(tam)2]ClO4‚3H2O (8)
[YbNi2(tam)2]ClO4‚3H2O (9)
(5.38)
6.72e
(5.39)
8.77e
(8.89)
11.91c
(11.33)
11.84e
(11.33)
11.05e
(10.37)
6.28c
(6.02)
a Found. b Expected. c Measured on a Quantum Design SQUID magnetometer at 300 K. d Calculated values based on g[J(J + 1)]1/2 e Measured
.
on a Johnson Matthey MSB-1 balance at room temperature.
Table 2. Crystallographic Data for Compounds 1, 2, 6, and 9
1
2
6
9
empirical formula
fw
space group
a, Å
b, Å
C
33.5H44.5F6N6.5NiO3.5
P
C55H54ClLaNi2O17N6
1362.82
C2/c (No. 15)
31.731(3)
23.491(3)
19.868(2)
90
124.924(6)
90
12143(2)
4
C54H69ClDyN6Ni2O14
1341.52
C2/c (No. 15)
31.9836(9)
22.2077(9)
20.1328(2)
90.0
123.7124(2)
90.0
11895.2(4)
8
C53H73.16ClN6Ni2O15.58Yb
1369.52
P21/c(No. 14)
14.9263(7)
18.5192(10)
22.5309(2)
90.0
92.5859(2)
90.0
6221.7(3)
4
797.94
C2/c (No. 15)
25.296(7)
16.163(6)
20.367(8)
90.0
105.30(2)
90.0
8032(5)
8
1.320
150(1)
0.710 69
0.592
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
F
obsd, mg m-3
T, (K)
λ, Å
0.745
173(2)
0.710 73
0.710
1.498
180(1)
0.710 69
1.983
1.462
180(1)
0.710 69
2.199
µ, mm-1
R1a
0.0616
0.0451
0.045
0.046
wR2a
0.1645b
0.1156b
0.099c
0.087c
a R1 and wR2 as defined in SHELX-93. b w ) 1/[σ2(Fo ) + (0.0827P)2], where P ) (Fo2 + 2Fc2)/3. c w ) 1/[σ2(Fo ) + (0.0322P)2], where P )
2
2
2
(Fo + 2Fc2)/3.
from CH3CN. Yield: 210 mg (80%). Anal. Calcd (found) for
C26H32F6N3NiO3P: C, 48.93 (48.88); H, 5.05 (5.15); N, 6.58 (6.41).
µeff(RT) ) 3.04 µB. Mass spectrum (LSIMS): m/z 492 ([Ni(H2tam)]+,
(s, s), 854 (w, s), 759 (m, s), 734 (w, s), 630 (m, s), 591 (m, s), 515
(w, s).
X-ray Crystallographic Data Collections and Refinements of the
Structures. Selected crystallographic data for complexes 1, 2, 6, and
9 are presented in Table 2. The data collection for 1 was undertaken at
150 K, while those for 2, 6, and 9 were performed at 180 K.
(a) [Ni(H2tam)]PF6 (1). Data collection for 1 was accomplished at
the University of Wales with a Delft Instruments FAST TV area detector
diffractometer positioned at the window of a rotating-anode generator.
Mo KR radiation (λ ) 0.710 69 Å) was used, and previously described
procedures were followed.15 The structure was solved by direct methods
(SHELXS)16a and refined on F2 by full-matrix least-squares procedures
(SHELX-93)16b using all unique F2 data corrected for Lorentz and
polarization factors and for absorption effects (DIFABS) (absorption
correction factors 0.872-0.987).16c
C26H32N3NiO3+), 983 ([Ni2(H2tam)2 - H]+, C52H63N6Ni2O6+). IR (cm-1
;
KBr disk): 3472 (m, vbr), 3272 (s, s), 3056 (w, s), 2934 (w, s), 2907
(w, s), 2861 (w, s), 1598 (s, s), 1479 (s, s), 1378 (w, s), 1352 (w, s),
1278 (m, s), 1241 (w, s), 918 (m, s), 897 (m, s), 873 (m, s), 840 (m,
s), 764 (m, s), 745 (m, s), 734 (w, s), 622 (s, s), 572 (m, s), 566 (m, s),
555 (w, s).
(b) General Procedure for [LnNi2(tam)2]ClO4‚nH2O (2-9). To
a solution of Ni(ClO4)2‚6H2O (100 mg, 0.27 mmol) in methanol (5
mL) was added H3tam (120 mg, 0.28 mmol) in methanol (5 mL). The
blue solution was left to stir at room temperature for 10 min, and
hydrated Ln(ClO4)3‚xH2O then was added (0.13 mmol). The solution
developed a light red hue (for all Ln complexes) and upon addition of
triethylamine (84 mg, 0.83 mmol) became more intensely colored. The
solution was allowed to stand for a few hours, and then 1.5 mL of
deionized water was added. The resulting clear solution was clarified
by filtration, and the filtrate was allowed to stand at room temperature.
Light-pink (for all Ln complexes) crystals suitable for crystallographic
study were formed; these were stable in the parent solvent and lost
coordinated (via MeOH-H2O exchange in parent solution) or lattice
MeOH in air. The yields of the air-dried products were 40-71%. The
compounds prepared and their analytical data are presented in Table
1. IR (cm-1; KBr disk) (all superimposable): 3442 (s, vbr), 3272 (s,
s), 3058 (w, s), 2914 (m, s), 1594 (s, s), 1566 (w, s), 1478 (s, s), 1456
(s, s), 1355 (w, s), 1281 (s, s), 995 (m, s), 920 (w, s), 896 (s, s), 878
Compound 1 contained a CH3CN molecule coordinated to Ni and
2.5 CH3CN and 0.5 CH3OH molecules (per complex cation) in the
lattice. Both lattice components were disordered and partially occupied.
There were two PF6- anions, each sited on 2-fold axes, thus generating
a total of one PF6- anion per complex cation. The hydrogen atoms on
(15) Drake, S. R.; Hursthouse, M. B.; Malik, K. M. A.; Miller, S. A. S.
Inorg. Chem. 1993, 32, 5704.
(16) (a) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467. (b)
Sheldrick, G. M. SHELX-93: Program for Crystal Structure Refine-
ment; University of Go¨ttingen: Go¨ttingen, Germany, 1993. (c) Walker,
N. P. C.; Stuart, D. Acta Crystallogr., Sect. A 1983, 39, 158. Adapted
for FAST geometry by A. Karaulov, University of Wales, Cardiff,
1991.

Coaggregation of d- and f-Block Metal Ions
Inorganic Chemistry, Vol. 39, No. 3, 2000 511
Table 4. Selected Bond Lengths (Å) and Angles (deg) for the
[LaNi2(tam)2(CH3OH)1/2(CH3CH2OH)1/2(H2O)]+ Cation in 2
La(1)-Ni(1)
La(1)-O(1)
La(1)-O(3)
La(1)-O(5)
La(1)-O(7)
La(1)-O(8d)
Ni(1)-O(2)
Ni(1)-N(1)
Ni(1)-N(3)
Ni(2)-O(5)
Ni(2)-N(4)
Ni(2)-N(6)
3.1900(7)
2.449(3)
2.450(3)
2.455(3)
2.638(3)
2.62(2)
2.050(3)
2.075(4)
2.093(4)
2.085(3)
2.081(4)
2.069(4)
La(1)-Ni(2)
La(1)-O(2)
La(1)-O(4)
La(1)-O(6)
La(1)-O(8)
Ni(1)-O(1)
Ni(1)-O(3)
Ni(1)-N(2)
Ni(2)-O(4)
Ni(2)-O(6)
Ni(2)-N(5)
3.1533(7)
2.472(3)
2.410(3)
2.496(3)
2.683(10)
2.101(3)
2.075(3)
2.078(3)
2.089(3)
2.061(3)
2.092(4)
Ni(1)-La(1)-O(6) 165.30(8) Ni(1)-La(1)-O(7) 112.01(12)
Ni(1)-La(1)-O(8) 99.7(3) Ni(1)-La(1)-O(8d) 100.9(4)
Ni(2)-La(1)-O(1) 126.69(8) Ni(2)-La(1)-O(2) 105.68(8)
Ni(2)-La(1)-O(3) 160.93(8) Ni(2)-La(1)-O(4)
41.47(7)
40.75(7)
Ni(2)-La(1)-O(5)
Ni(2)-La(1)-O(7)
41.35(7) Ni(2)-La(1)-O(6)
97.80(11) Ni(2)-La(1)-O(8) 108.8(3)
Ni(2)-La(1)-O(8d) 113.0(6)
O(1)-La(1)-O(2)
68.66(10)
145.80(11)
124.15(11)
73.0(7)
67.96(11)
84.31(11)
119.4(2)
O(1)-La(1)-O(3)
O(1)-La(1)-O(5)
O(1)-La(1)-O(7)
O(1)-La(1)-O(8d)
O(2)-La(1)-O(4)
O(2)-La(1)-O(6)
O(2)-La(1)-O(8)
O(3)-La(1)-O(4)
O(3)-La(1)-O(6)
O(3)-La(1)-O(8)
O(4)-La(1)-O(5)
O(4)-La(1)-O(7)
69.09(11) O(1)-La(1)-O(4)
86.14(11) O(1)-La(1)-O(6)
132.28(14) O(1)-La(1)-O(8)
Figure 1. Structure of the [Ni(H2tam)(CH3CN)]+ cation in 1. Thermal
ellipsoids are drawn at 50% probability, and hydrogen atoms are omitted
for clarity.
82.3(8)
O(2)-La(1)-O(3)
83.76(10) O(2)-La(1)-O(5)
146.34(10) O(2)-La(1)-O(7)
138.8(4)
O(2)-La(1)-O(8d) 140.7(4)
Table 3. Selected Bond Lengths (Å) and Angles (deg) for the
[Ni(H2tam)]+ Cation in 1
119.55(11) O(3)-La(1)-O(5)
147.79(11)
71.97(14)
77.4(9)
70.38(10)
137.4(5)
67.33(11)
107.7(7)
77.04(14)
72.3(6)
143.90(11) O(3)-La(1)-O(7)
Ni(1)-O(2)
Ni(1)-N(1)
Ni(1)-N(2)
2.035(3)
2.077(4)
2.083(4)
Ni(1)-N(4)
Ni(1)-O(1)
Ni(1)-N(3)
2.075(5)
2.078(3)
2.111(4)
85.1(4)
O(3)-La(1)-O(8d)
70.87(11) O(4)-La(1)-O(6)
78.56(14) O(4)-La(1)-O(8)
O(4)-La(1)-O(8d) 131.1(7)
O(5)-La(1)-O(7)
O(5)-La(1)-O(6)
O(2)-Ni(1)-N(4)
N(4)-Ni(1)-N(1)
N(4)-Ni(1)-O(1)
O(2)-Ni(1)-N(2)
N(1)-Ni(1)-N(2)
O(2)-Ni(1)-N(3)
N(1)-Ni(1)-N(3)
N(2)-Ni(1)-N(3)
88.8(2)
176.1(2)
91.5(2)
91.3(2)
87.7(2)
175.5(2)
87.3(2)
90.8(2)
O(2)-Ni(1)-N(1)
O(2)-Ni(1)-O(1)
N(1)-Ni(1)-O(1)
N(4)-Ni(1)-N(2)
O(1)-Ni(1)-N(2)
N(4)-Ni(1)-N(3)
O(1)-Ni(1)-N(3)
C(9)-O(1)-Ni(1)
88.9(2)
87.97(13)
91.5(2)
89.2(2)
179.00(14)
95.2(2)
138.91(13) O(5)-La(1)-O(8)
O(5)-La(1)-O(8d) 120.6(14) O(6)-La(1)-O(7)
O(6)-La(1)-O(8)
O(7)-La(1)-O(8)
La(1)-Ni(1)-O(1)
La(1)-Ni(1)-O(3)
70.3(3)
77.3(9)
O(6)-La(1)-O(8d)
O(7)-La(1)-O(8d)
63.0(14)
50.80(9)
50.13(8) La(1)-Ni(1)-O(2)
50.19(9) La(1)-Ni(1)-N(1) 125.09(11)
89.8(2)
121.9(3)
La(1)-Ni(1)-N(2) 126.09(11) La(1)-Ni(1)-N(3) 125.71(11)
O(1)-Ni(1)-O(2)
O(1)-Ni(1)-N(1)
O(1)-Ni(1)-N(3)
O(2)-Ni(1)-N(1)
O(2)-Ni(1)-N(3)
O(3)-Ni(1)-N(2)
N(1)-Ni(1)-N(2)
N(2)-Ni(1)-N(3)
La(1)-Ni(2)-O(5)
83.92(13) O(1)-Ni(1)-O(3)
92.19(14) O(1)-Ni(1)-N(2)
175.35(14) O(2)-Ni(1)-O(3)
175.71(14) O(2)-Ni(1)-N(2)
83.42(13)
93.66(14)
83.68(13)
93.72(14)
94.10(14)
92.1(2)
89.3(2)
49.82(8)
52.24(9)
the phenolic O(1) and CH3OH solvate were ignored; others were
included in calculated positions (riding model). All non-hydrogen atoms
were refined with anisotropic displacement coefficients, with those for
the acetonitrile species being restrained using an ISOR 0.01 instruction
in SHELX-93. The C-N and C-C distances in the acetonitrile
molecules were also restrained to refine to the same group values.
Selected distances and angles are shown in Table 3, and an ORTEP
drawing of the complex cation is presented in Figure 1.
(b) [LaNi2(tam)2(CH3OH)1/2(CH3CH2OH)1/2(H2O)]ClO4‚0.5CH3OH‚
0.5CH3CH2OH‚4H2O (2). Data collection for 2 was undertaken at the
University of Minnesota. A violet crystal of approximate dimensions
0.13 × 0.13 × 0.07 mm3 was attached to the tip of a 0.1 mm diameter
glass capillary, which was then mounted on a Siemens SMART system
for data collection at 173(2) K. The data collection was carried out
using Mo KR radiation (graphite monochromator) with a detector
distance of 4.934 cm. A randomly oriented region of reciprocal space
was surveyed to the extent of 1.3 hemispheres and to a resolution of
0.84 Å. Three major sections of frames were collected with 0.30° steps
in ω at three different φ settings and a detector position of -25° in 2θ
with a frame time of 30 s. Selected distances and angles are shown in
Table 4, and an ORTEP drawing of the complex cation is presented in
Figure 2.
94.4(2)
O(3)-Ni(1)-N(1)
176.27(14) O(3)-Ni(1)-N(3)
88.3(2)
90.8(2)
N(1)-Ni(1)-N(3)
La(1)-Ni(2)-O(4)
51.07(9) La(1)-Ni(2)-O(6)
La(1)-Ni(2)-N(4) 124.47(10) La(1)-Ni(2)-N(5) 127.08(10)
La(1)-Ni(2)-N(6) 123.56(10) O(4)-Ni(2)-O(5)
85.02(13)
91.94(13)
91.29(13)
94.38(14)
174.60(14)
92.8(2)
O(4)-Ni(2)-O(6)
O(4)-Ni(2)-N(5)
O(5)-Ni(2)-O(6)
O(5)-Ni(2)-N(5)
O(6)-Ni(2)-N(4)
O(6)-Ni(2)-N(6)
N(4)-Ni(2)-N(6)
85.90(13) O(4)-Ni(2)-N(4)
176.53(13) O(4)-Ni(2)-N(6)
82.91(13) O(5)-Ni(2)-N(4)
91.6(2)
O(5)-Ni(2)-N(6)
176.67(13) O(6)-Ni(2)-N(5)
92.90(14) N(4)-Ni(2)-N(5)
89.7(2)
89.2(2)
92.0(2)
N(5)-Ni(2)-N(6)
1
occupancy /2, located on an inversion center). However, the location
of the remaining half of the anion and solvent molecules was not
determinable due to the large voids in the unit cell. These voids allowed
for disordered solvent molecules and made it necessary to correct the
data using PLATON.18 The voids are situated in the vicinity of a
disordered oxygen, O(8)/O(8d), belonging 67% of the time to an alcohol
and 33% of the time to water. All non-hydrogen atoms were refined
with anisotropic displacement parameters except for those of half of a
perchlorate (Cl(2), ...). The hydrogen atoms were placed in ideal
positions and refined as riding atoms with individual or group isotropic
displacement parameters or were found from the E map. The final full-
matrix least-squares refinement converged to R1 ) 0.0451 and wR2
The structure was solved and refined using SHELX-86 and SHELX-
97.17 The space group C2/c was determined on the basis of systematic
absences and intensity statistics. The heavy-atom positions were
determined from a Patterson solution. Full-matrix least-squares/
difference Fourier cycles were performed, locating the remaining non-
hydrogen atoms of the cationic complex and the perchlorate anion (site
(17) SHELXTL-Plus V5.1; Bruker-AXS: Madison, WI, 1998.
(18) Spek, A. L. PLATON: Acta Crystallogr., Sect. A 1990, A46, 34.

512 Inorganic Chemistry, Vol. 39, No. 3, 2000
Xu et al.
Table 5. Selected Bond Lengths (Å) Angles (deg) for the
[DyNi2(tam)2(CH3OH)(H2O)]+ Cation in 6
Dy(1)-Ni(1)
Dy(1)-O(1)
Dy(1)-O(3)
Dy(1)-O(5)
Ni(1)-O(1)
Ni(1)-O(3)
Ni(1)-N(2)
Ni(2)-O(4)
Ni(2)-O(6)
Ni(1)-N(5)
O(1)-C(6)
O(3)-C(22)
O(5)-C(35)
3.0134(7)
2.268(3)
2.286(4)
2.257(3)
2.082(4)
2.055(4)
2.072(4)
2.080(4)
2.070(4)
2.098(5)
1.342(6)
1.339(6)
1.355(6)
Dy(1)-Ni(2)
Dy(1)-O(2)
Dy(1)-O(4)
Dy(1)-O(7)
Ni(1)-O(2)
Ni(1)-N(1)
Ni(1)-N(3)
Ni(2)-O(5)
Ni(2)-N(4)
Ni(2)-N(6)
O(2)-C(14)
O(4)-C(32)
O(6)-C(48)
3.2542(7)
2.273(4)
2.267(3)
2.398(4)
2.061(3)
2.063(4)
2.053(3)
2.095(3)
2.091(4)
2.056(5)
1.329(6)
1.342(6)
1.330(6)
O(1)-Dy(1)-O(2)
74.55(12) O(1)-Dy(1)-O(3)
72.63(12)
O(1)-Dy(1)-O(4) 163.81(13) O(1)-Dy(1)-O(5) 119.36(12)
O(1)-Dy(1)-O(7) 105.23(12) O(1)-Dy(1)-O(8)
75.56(13)
90.37(12)
76.66(13)
97.22(13)
O(2)-Dy(1)-O(3)
71.10(12) O(2)-Dy(1)-O(4)
Figure 2. Structure of the [LaNi2(tam)2(CH3OH)1/2(CH3CH2OH)1/2
-
(H2O)]+ cation in 2. Thermal ellipsoids are drawn at 50% probability,
O(2)-Dy(1)-O(5) 154.93(14) O(2)-Dy(1)-O(7)
O(2)-Dy(1)-O(8) 129.03(14) O(3)-Dy(1)-O(4)
and hydrogen and ring carbon atoms are omitted for clarity.
O(3)-Dy(1)-O(5)
92.36(13) O(3)-Dy(1)-O(7) 147.08(14)
72.68(12)
76.22(13) O(4)-Dy(1)-O(8) 119.56(13)
O(3)-Dy(1)-O(8) 134.60(13) O(4)-Dy(1)-O(5)
O(4)-Dy(1)-O(7)
) 0.1213 (F2, all data). The modified dataset improved the R1 value
by approximately 1.5%.
O(5)-Dy(1)-O(7) 115.40(13) O(5)-Dy(1)-O(8)
76.00(15)
83.19(14)
92.04(15)
(c) [DyNi2(tam)2(CH3OH)(H2O)]ClO4‚CH3OH‚H2O (6) and [YbNi2-
(tam)2(H2O)]ClO4‚2.58H2O (9). These structures were determined at
the University of British Columbia. A pink (dark) prism crystal of
complex 6 (9) was mounted on a glass fiber. All measurements were
made on a Rigaku/ADSC CCD area detector with graphite-monochro-
mated Mo KR radiation. The data were collected at a temperature of
180 ( 1 K to a maximum 2θ value of 61.1° (61.0°) and at 0.30°
oscillations with 10.0 s (20.0 s) exposures. A sweep of data was
performed using φ oscillations from -23.0 to +17.8° at ø ) -90°
(+89.9°), and a second sweep was performed using ω oscillations
between 0 and 180° at ø ) -90°. The structures were solved by the
heavy-atom Patterson method19 and expanded using Fourier tech-
niques.20 In 6, there is half of a perchlorate ion disordered about a
center of symmetry. The other perchlorate could not be located and
most likely resides, along with disordered methanol and water, in the
primary solvent region. All calculations were performed using the
teXsan21 crystallographic software package.
Selected distances and angles are shown in Tables 5 and 6 for
compounds 6 and 9, respectively, while ORTEP drawings of the
complex cations in 6 and 9 are presented in Figures 3 and 4,
respectively.
Full details of the structure solutions for 1, 2, 6, and 9, as well as
complete tables of crystallographic data, atomic coordinates and
equivalent isotropic thermal parameters, hydrogen atom parameters,
anisotropic thermal parameters, bond lengths, bond angles, torsion
angles, intermolecular contacts, and least-squares planes, are included
as Supporting Information.
O(7)-Dy(1)-O(8)
O(1)-Ni(1)-O(3)
O(1)-Ni(1)-N(2)
O(2)-Ni(1)-O(3)
O(2)-Ni(1)-N(2)
O(3)-Ni(1)-N(1)
O(3)-Ni(1)-N(3)
N(1)-Ni(1)-N(3)
O(4)-Ni(2)-O(5)
O(4)-Ni(2)-N(4)
72.66(15) O(1)-Ni(1)-O(2)
81.39(15) O(1)-Ni(1)-N(1)
94.5(2)
O(1)-Ni(1)-N(3) 174.44(15)
80.19(14) O(2)-Ni(1)-N(1) 175.0(2)
92.66(15) O(2)-Ni(1)-N(3) 92.85(15)
97.5(2)
94.1(2)
91.8(2)
79.90(13) O(4)-Ni(1)-O(6)
91.87(15) O(4)-Ni(2)-N(5)
O(3)-Ni(1)-N(2) 172.10(15)
N(1)-Ni(1)-N(2)
N(2)-Ni(1)-N(3)
89.3(2)
89.6(2)
88.33(14)
92.4(2)
90.26(14)
90.08(14)
91.97(15)
91.97(15)
92.3(2)
O(4)-Ni(2)-N(6) 175.79(14) O(5)-Ni(2)-O(6)
O(5)-Ni(2)-N(4) 171.4(2)
O(5)-Ni(2)-N(6)
O(5)-Ni(2)-N(5)
95.99(14) O(6)-Ni(2)-N(4)
O(6)-Ni(2)-N(5) 179.3(2)
O(6)-Ni(2)-N(6)
N(4)-Ni(2)-N(6)
N(4)-Ni(2)-N(5)
N(5)-Ni(2)-N(6)
87.8(2)
88.5(2)
(a) [Ni(H2tam)(CH3CN)]PF6 (1). The room-temperature
addition of H3tam to methanolic solutions of NiX2‚6H2O (X )
Cl-, NO3-, PF6-, ClO4-, BPh4-) afforded purple solutions from
which materials of stoichiometry [Ni(H2tam)]X were isolated
in moderate to good yields. These materials were soluble in
alcohols and acetonitrile, and their elemental analyses confirmed
the proposed general stoichiometry. If, however, the reaction
mixtures were allowed to stand for longer periods of time (>2
h; X ) Cl-, NO3-, ClO4-), precipitates formed that had the
same mass analysis as 1, but a dimeric structure in the solid
state, for instance, [Ni2(H2tam)2Cl]Cl, which was structurally
characterized but could not be refined to a publishable level.22
[Ni(H2tam)]PF6 had a room-temperature solid-state magnetic
moment of 3.04 µB, which is consistent with a d8 octahedral
species.
The structure of the cation [Ni(H2tam)(CH3CN)]+ as its PF6
salt is shown in Figure 1, while selected bond lengths and angles
in the cation are presented in Table 3. The solid-state structure
of 1 revealed that the Ni(II) ion has an octahedral geometry, its
coordination sphere defined by one phenolato, one phenol, and
three amine functions from the ligand [H2tam]-. The sixth site
is occupied by a CH3CN solvent molecule. The coordination
environment is best described as a distorted octahedron. The
third ligand phenol OH is neither deprotonated nor coordinated
to the Ni center. In this complex, the Ni(II) center has a greater
preference for the three amine functions versus the three phenol
Results and Discussion
Structures. To evaluate the ability of the H3tam ligand to
coaggregate d- and f-block metal ions, it was first necessary to
study the reactions of the ligand with Ni2+ alone. The isolation
of a Ni2+-H3tam binary complex was important to this study
because it is the building block from which the larger coag-
gregated LnM2 complexes are formed.
(19) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.; Garcia-
Granda, S.; Gould, R. O.; Smits, J. M. M.; Smykalla, C. PATTY. In
The DIRDIF program system; Technical Report; Crystallography
Laboratory, University of Nijmegen: Nijmegen, The Netherlands,
1992.
(20) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.; de
Gelder, R.; Israel, R.; Smits, J. M. M. The DIRDIF-94 program system;
Technical Report; Crystallography Laboratory, University of
Nijmegen: Nijmegen, The Nertherlands, 1994.
(21) teXsan: Crystal Structure Analysis Package; Molecular Structure
Corp.: The Woodlands, TX, 1985 and 1992.
(22) Read, P. W.; Yap, G.; Orvig, C. Unpublished results.

Coaggregation of d- and f-Block Metal Ions
Inorganic Chemistry, Vol. 39, No. 3, 2000 513
Figure 4. Structure of the [YbNi2(tam)2]+ cation in 9. Thermal
ellipsoids are drawn at 50% probability, and hydrogen and ring carbon
atoms are omitted for clarity.
Figure 3. Structure of the [DyNi2(tam)2(CH3OH)(H2O)]+ cation in 6.
Thermal ellipsoids are drawn at 50% probability, and hydrogen and
ring carbon atoms are omitted for clarity.
The average Ni-O and Ni-N bond lengths (2.056(3) and 2.086-
(5) Å, respectively) are in good agreement with previous
literature examples [e.g., Ni-O ) 2.08 Å in [NiL3]2+ (L )
HOCH2CH2NH2)24a,b and Ni-N ) 2.05 Å in Ni[L2]2+ (L )
H2NCH2CH2)2NH)24c], although the Ni-N bond lengths are
shorter than expected for six-membered chelate rings, which
are typically around 2.22 Å.24d The Ni-acetonitrile Ni(1)-N(4)
bond length (2.075(5) Å) also agrees with literature values.25
One of the Ni-O bonds is 0.043 Å shorter than the other (Ni-
(1)-O(2) ) 2.035(3) Å versus Ni(1)-O(1) ) 2.078(3) Å), and
therefore, O(2) is tentatively assigned as the deprotonated
phenolato function. It is interesting to note that there is a
lengthening of the Ni-N bond trans to the deprotonated
phenolato O(2) (Ni(1)-N(3) ) 2.111(4) Å) relative to that trans
to the protonated phenol function O(1) (Ni(1)-N(2) ) 2.083-
(4) Å). This is probably attributable to the different trans
influence of a coordinated phenol OH versus a phenolato O-
function. It is unlikely to be a consequence of chelate strain
within the molecule, since N(3) is only involved in two six-
membered chelate rings with the Ni center (with N(1) and N(2)),
whereas both N(1) and N(2) are involved in three chelate
rings: N(2), N(3), O(1) and N(1), N(3), O(2), respectively. All
chelate rings within the complex are six membered, and these
impart a lower stability than do five-membered chelate rings.
Thus, N(3) should be able to attain a closer Ni interaction since
Table 6. Selected Bond Lengths (Å) and Angles (deg) for the
[YbNi2(tam)2]+ Cation in 9
Yb(1)-Ni(1)
Yb(1)-O(1)
Yb(1)-O(3)
Yb(1)-O(5)
Ni(1)-O(1)
Ni(1)-O(3)
Ni(1)-N(2)
Ni(2)-O(4)
Ni(2)-O(6)
Ni(2)-N(5)
2.9081(8)
2.207(3)
2.224(4)
2.176(3)
2.066(4)
2.098(3)
2.045(6)
2.126(4)
2.019(4)
2.083(5)
Yb(1)-Ni(2)
Yb(1)-O(2)
Yb(1)-O(4)
Yb(1)-O(7)
Ni(1)-O(2)
Ni(1)-N(1)
Ni(1)-N(3)
Ni(2)-O(5)
Ni(2)-N(4)
Ni(1)-N(6)
3.2702(7)
2.205(3)
2.184(4)
2.228(4)
2.095(4)
2.054(4)
2.053(3)
2.124(4)
2.093(5)
2.082(4)
O(1)-Yb(1)-O(2)
77.78(12) O(1)-Yb(1)-O(3)
75.77(14)
99.31(12)
75.83(14)
O(1)-Yb(1)-O(4) 172.49(13) O(1)-Yb(1)-O(5)
O(1)-Yb(1)-O(7)
O(2)-Yb(1)-O(4) 104.97(13) O(2)-Yb(1)-O(5) 175.03(14)
95.94(14) O(2)-Yb(1)-O(3)
O(2)-Yb(1)-O(7)
O(3)-Yb(1)-O(5)
O(4)-Yb(1)-O(5)
O(5)-Yb(1)-O(7)
O(1)-Ni(1)-O(3)
94.14(14) O(3)-Yb(1)-O(4)
99.61(13) O(3)-Yb(1)-O(7) 168.03(12)
77.43(13) O(4)-Yb(1)-O(7)
90.16(14) O(1)-Ni(1)-O(2)
81.62(14) O(1)-Ni(1)-N(1)
97.97(14)
90.86(14)
83.50(14)
93.1(2)
92.7(2)
95.9(2)
O(1)-Ni(1)-N(2) 175.1(2)
O(1)-Ni(1)-N(3)
80.96(14) O(2)-Ni(1)-N(1)
92.0(2)
O(2)-Ni(1)-O(3)
O(2)-Ni(1)-N(2)
O(2)-Ni(1)-N(3) 171.67(15)
O(3)-Ni(1)-N(1) 174.1(2)
O(3)-Ni(1)-N(2)
N(1)-Ni(1)-N(2)
N(2)-Ni(1)-N(3)
95.7(2)
89.4(2)
91.5(2)
89.93(14)
O(3)-Ni(1)-N(3)
N(1)-Ni(1)-N(3)
O(4)-Ni(2)-O(5)
O(4)-Ni(2)-N(4)
O(4)-Ni(2)-N(6)
O(5)-Ni(2)-N(4)
91.2(2)
91.7(2)
79.81(14) O(4)-Ni(1)-O(6)
90.2(2)
97.3(2)
91.1(2)
O(4)-Ni(2)-N(5) 172.3(2)
O(5)-Ni(2)-O(6)
O(5)-Ni(2)-N(5)
90.38(14)
92.5(2)
(23) Stephens, A. K. W.; Orvig, C. J. Chem. Soc., Dalton Trans. 1998,
3049.
(24) (a) Bertrand, J. A.; Howard, W. J.; Kalyararaman, A. R. J. Chem.
Soc., Chem. Commun. 1971, 437. (b) Rastorgi, S. C.; Rao, G. N. J.
Inorg. Nucl. Chem. 1974, 36, 161. (c) Biagini, S.; Cannas, M. J. Chem.
Soc. A 1970, 2398. (d) Vacca, A.; Arenare, D.; Paoletti, P. Inorg.
Chem. 1966, 5, 1384.
O(5)-Ni(2)-N(6) 176.4(2)
O(6)-Ni(2)-N(4) 178.5(2)
O(6)-Ni(2)-N(5)
N(4)-Ni(2)-N(5)
N(5)-Ni(2)-N(6)
90.0(2)
90.0(2)
90.4(2)
O(6)-Ni(2)-N(6)
N(4)-Ni(2)-N(6)
91.8(2)
86.7(2)
groups. Once this preference has been indulged, the strain within
the molecule prevents [H2tam]- from becoming hexadentate.23
(25) Sotofte, S.; Gronbaer, R.; Rasmussen, S. E. Acta Crystallogr., Sect. B
1968, 87, 513.

514 Inorganic Chemistry, Vol. 39, No. 3, 2000
Xu et al.
Figure 6. UV/vis spectra of 2, 6, and 9 in CH2Cl2.
form bridging bonds between the Ni(II) and La(III) ions.
Two solvent molecules [one being water (O(7)) and the second
being water (O(8d)), methanol, or ethanol (O(3))] occupy the
remaining coordination sites on the lanthanum(III) ion. The
[LaNi2(tam)2(CH3OH)1/2(CH3CH2OH)1/2(H2O)]+ cation is not
linear. A detailed shape analysis26 determined that the geometry
of the La(III) ion is best described as a D4d square antiprism,
distorted toward a C2V bicapped octahedron. The Ni-La
distances are 3.1900(7) Å (La(1)-Ni(1)) and 3.1533(7) Å (La-
(1)-Ni(2)), which are shorter than previously observed in other
Ni-La systems, such as the tren-based amine phenol La/Ni
system described by Archibald et al. where Ni-La ) 3.355(5)
Å.27 The average La-O(ligand) bond lengths (2.519 Å) are in
good agreement with other crystallographically characterized
examples of the ligand [tam]3-. The average Ni-O bond lengths
(2.075(3) Å for Ni(1) and 2.078(3) Å for Ni(2)) are slightly
longer and the average Ni-N bond lengths (2.082(4) Å for Ni-
(1) and 2.081(4) Å for Ni(2)) are slightly shorter than observed
in the parent complex (1) (average Ni-O(phenoxy) ) 2.035(3) Å
and Ni-N(ligand) ) 2.0767(4) Å). This was to be expected,
since the acidic lanthanide(III) ion will withdraw electron density
from the [Ni(tam)]- moiety.28 This will have a two-fold effect:
First, the Ni-O bonds will be slightly lengthened since the
phenolato groups become bridging. Second, the trans amino
groups will be pulled closer to the Ni(II) ion, and hence their
bond lengths to Ni will be shortened. The fact that the two nickel
centers in 2 are in comparable environments is also reflected
by the UV/vis spectrum (see Figure 6), which indicates that
there is no splitting in either the 860 nm (ν1, 3A2g f 3T2g, ꢀ )
Figure 5. Mass spectrum (LSIMS) of [LaNi2(tam)2]+ (insert: calcu-
lated parent peak).
it is less sterically encumbered and less destabilized by being
in an unfavorably sized chelate ring.
Also present in the unit cell are the PF6- counterion and 2.5
acetonitrile and 0.5 methanol disordered solvate molecules. Two
PF6- moieties are present in the unit cell, each sitting on a 2-fold
-
axis, generating one PF6 per cation.
(b) [LnNi2(tam)2]ClO4‚nH2O (2-9). The [Ni(H2tam)]+ (vide
infra) moiety can be deprotonated and used as an encapsulated
ligand for a variety of Ln(III) ions in a bicapped fashion (see
Chart 1) to generate isolable complexes which are the result of
a spontaneous self-assembly: [LnNi2(tam)2]+ (Ln ) La, Pr, Nd,
Gd, Dy, Ho, Er, Yb) cations.
The reaction of methanolic solutions of [Ni(H2tam)]ClO4 with
hydrated lanthanide(III) perchlorate salts in the presence of base
(NEt3) afforded purple solutions, from which crystals of the
corresponding lanthanide complexes (Table 1) could be isolated
in moderate to good yields. The amount of base added to the
reaction mixtures was important; if even slight excesses were
employed, complexes of the stoichiometry indicated could not
be isolated. Microanalyses confirmed the proposed stoichiom-
etry, and LSIMS mass spectrometry was particularly diagnostic
for the presence of the appropriate [LnNi2(tam)2]+ moiety in
each complex (Figure 5). IR studies showed that the complexes
had initially superimposable spectra, suggesting that in the solid
state all complexes had similar structures. The complexes
prepared and their analytical data are presented in Table 1; they
were all paramagnetic in the solid state.
Reasonably good single crystals of 2-9 were obtained;
however, only three of these [LnNi2(tam)2]+ complexes were
structurally elucidated by X-ray diffraction [Ln ) La (2), Dy
(6), Yb (9)]. In most cases, the single crystals were obtained
from the parent solvent; some, however, were obtained in purer
form by recrystallization from a methanol/water mixed solvent
(5:1).
(c) [LaNi2(tam)2(CH3OH)1/2(CH3CH2OH)1/2(H2O)]ClO4‚
0.5CH3OH‚0.5CH3CH2OH‚4H2O (2). The structure of the
cation [LaNi2(tam)2(CH3OH)1/2(CH3CH2OH)1/2(H2O)]+ in 2 is
depicted in Figure 2, where the carbon atoms in the ligand
phenyl rings are omitted for clarity, and selected bond distances
and angles are listed in Table 4. The [LaNi2(tam)2]+ cation
contains an eight-coordinate La(III) ion bonded to two [tam]3-
ligands, each of which is tridentate with respect to the La(III)
ion and hexadentate with respect to one Ni(II) ion. Each [tam]3-
ligand encapsulates a Ni(II) ion via its three amine and three
phenolato functions, rendering each Ni(II) coordination sphere
approximately octahedral. All six phenols are deprotonated and
147 M-1 cm-1) or the 540 nm (ν2, A2gf T1g, ꢀ ) 122 M-1
cm-1) absorptions.29 The ν3 band for all of these compounds,
however, was not observed, being obscured by a very strong
charge-transfer band at 285 nm (ꢀ ) 3.9 × 104 M-1 cm-1).
The particular Ni-Ln-Ni (Ln ) La in this case) arrangement
found in this series of compounds is very similar to that found
in a series of linear thiophenolate-bridged heterotrinuclear
transition metal complexes reported very recently.30
(d) [DyNi2(tam)2(CH3OH)(H2O)]ClO4‚CH3OH‚H2O (6).
The structure of the [DyNi2(tam)2]+ cation in 6 shares some
similarities with its La(III) analogue (2). The cation, which has
C1 symmetry, contains a Dy(III) ion with two [Ni(tam)]- units
coordinated to it. The Dy(III) ion is seven-coordinate, being
coordinated by two [Ni(tam)]- complex ligands, one bidentate
3
3
(26) (a) Porai-Koshits, M. A.; Aslanov, L. A. Zh. Strukt. Khim. 1972, 13,
266. (b) Muetterties, E. L.; Guggenburger, L. J. J. Am. Chem. Soc.
1974, 96, 1748.
(27) Archibald, S. J.; Blake, A. J.; Parsons, S.; Schro¨der, M. J. Chem. Soc.,
Dalton Trans. 1997, 173.
(28) Templeton, D. H.; Dauben, C. H. J. Am. Chem. Soc. 1954, 76, 5237.
(29) Lever, A. B. P., Inorganic Electronic Spectroscopy, Elsevier: New
York, 1984.
(30) (a) Glaser, T.; Beissel, T.; Bill, E.; Weyhermu¨ller, T.; Schu¨nemann,
V.; Meyer-Klaucke, W.; Trautwein, A. X.; Wieghardt. K. J. Am. Chem.
Soc. 1999, 121, 2193. (b) Glaser, T.; Bill, E.; Weyhermu¨ller, T.;
Meyer-Klaucke, W.; Wieghardt. K. Inorg. Chem. 1999, 38, 2632.

Coaggregation of d- and f-Block Metal Ions
Inorganic Chemistry, Vol. 39, No. 3, 2000 515
and one tridentate (vide infra). Each [tam]3- ligand encapsulates
a Ni(II) ion metal via its three amine and three phenolato
functions, which results in each Ni(II) ion having approximately
octahedral geometry. All of the phenolato functions are depro-
tonated; only five of them, however, bridge between the Ni(II)
and Dy(III) ions. One of the phenolato O atoms (O(6)) has a
very long interaction (Dy(1)-O(6) ) 3.197(3) Å) and hence is
not formally bonded to the Dy(III) ion. One methanol and one
water molecule occupy the remaining coordination sites on the
dysprosium(III) ion. The DyNi2 cation is not linear. A detailed
shape analysis26 determined that the geometry of the Dy(III)
ion was best described as capped trigonal prismatic.
The average Ni-Dy distance is 3.1338(7) Å (e.g., Dy(1)-
Ni(1) ) 3.0134(7) Å and Dy(1)-Ni(2) ) 3.2542(7) Å), which
is shorter than one would expect by comparison with the LaNi2
analogue (cf. average La-Ni ) 3.1717(7) Å). This can be
explained upon closer inspection of the relevant Ln-O bond
lengths and Ln-O-Ni angles. From Tables 4 and 5, it can be
seen that the corresponding La-O bond distances are signifi-
cantly longer than those of Dy-O [e.g., La(1)-O(4) ) 2.410-
(3) Å and La(1)-O(2) ) 2.472(3) Å, while Dy(1)-O(4) )
2.267(3) Å and Dy(1)-O(2) ) 2.273(4) Å], which obviously
results from the lanthanide contraction (ionic radii for La3+ and
Dy3+ (both CN ) 8) are 1.216 and 1.027 Å, respectively31).
On the other hand, the corresponding Ni-O bond distances and
Ln-O-Ni angles are comparable. The Dy-O(ligand) bond
lengths show no significant differences between the halves of
the molecule. The average bond length is 2.275(4) Å, normal
for Dy-O bonds.
ligand, are significantly longer than the corresponding Dy-O
distances in 6 (an obvious result of the lanthanide contraction
effect - ionic radius of Yb3+ (CN ) 7) is only 0.925 Å31). The
corresponding Ni-O and Ni-N bond lengths, however, are very
similar to those in 6 and also show differences when their values
within each [Ni(tam)]- moiety are compared, which is illustrated
by the split bands in the UV/vis spectrum of 9 (see Figure 6).
The majority of prior studies into the coaggregation of metal
ions have generally involved only two metal ions.27,32 Cases
where more than two metal ions have been assembled into novel
complexes have largely been fortuitous, since the resultant
complexes are generally the result of oligomerization of a
simpler species with a ligand (or counterion) that has a capacity
to bridge.33 In our system, however, the approach taken was to
build lanthanides into a construct where the precursor transition
metal complex of the encapsulated type in Chart 1 acts as a
ligand for a Ln(III) ion in a bicapped fashion. This design has
successfully generated complexes that contain novel architec-
tures, wherein [Ni(tam)]- caps a lanthanide(III) ion. This
approach in itself is not novel; the fact that two [Ni(tam)]- units
cap the lanthanide is. This type of arrangement has not been
observed previously for amine phenol ligands. It has, however,
been observed for Schiff base ligands, which have less flex-
ibility, resulting in greater 3d-4f distances.34
Magnetic Properties. Magnetic susceptibilities were mea-
sured on powdered samples of 2, 6, and 9 at an applied field of
10 000 G over the temperature range 2-300 K. The results are
shown as plots of effective magnetic moment (on a per mole
of LnNi2 basis) versus temperature in Figure 7. The lanthanide
in 2 is diamagnetic (La(III), S ) 0), and hence the magnetization
in this sample arises solely from the Ni(II) (S ) 1) ions. The
Ni(II) ions are octahedrally coordinated and are expected,
therefore, to exhibit spin-only moments modified by the effects
of second-order spin-orbit coupling, which leads to a g value
in excess of 2.35 The value of µeff at 300 K is 4.44 µB,
corresponding to two Ni(II) ions with µeff(per Ni) ) µNi ) 3.14
µB and g ) 2.22. The moment decreases only marginally from
300 to 10 K, below which a rather sharp drop due to the effects
of zero-field splitting is seen (Figure 7). In summary, the
magnetic behavior of 2 is consistent with the presence of two
magnetically isolated octahedral Ni(II) centers.
The average Ni-O bond lengths within each [Ni(tam)]-
moiety are significantly different. The average Ni(1)-O bond
length is 2.066(4) Å, while the average Ni(2)-O bond length
is 2.082(4) Å. The average Ni-N bond lengths also show the
same trend (average Ni(1)-N ) 2.063(4) and average Ni(2)-N
) 2.082(4) Å). Even though it is a fact that the Ni-O and Ni-N
bond distances in both nickel centers are within expected values,
the shorter Ni(1)-O and Ni(1)-N bond distances might suggest
that the better bridging between Dy and Ni(1) via three
phenolato oxo groups (O(1), O(2), O(3)) creates a better
coordination environment for Ni(1). The difference in coordina-
tion environment between these two nickel centers is shown in
the UV/vis spectrum of 6 (see Figure 6), in which the band ν1
3
(32) (a) Ramade, I.; Kahn, O.; Jeannin, Y.; Robert, F. Inorg. Chem. 1997,
36, 930. (b) Piguet, C.; Rivara-Minten, E.; Bernardinelli, G.; Bunzli,
J.-C. G.; Hopfgartner, G. J. Chem. Soc., Dalton Trans. 1997, 421. (c)
Costes, J.-P.; Dahan, F.; Dupuis, A.; Laurent, J. P. Inorg. Chem. 1996,
35, 2400. (d) Wang, S.; Pang, Z.; Smith, K. D. L.; Hua, Y.; Deslippe,
C.; Wagner, M. J. Inorg. Chem. 1995, 34, 908. (e) Chen, L.; Breeze,
S. R.; Rousseau, R. J.; Wang, S.; Thompson, L. K. Inorg. Chem. 1995,
34, 454. (f) Benelli, C.; Blake, A. J.; Milne, P. E. Y.; Rawson, J. M.;
Winpenny, R. E. P. Chem.sEur. J. 1995, 1, 614. (g) Benelli, C.;
Fabretti, A. C.; Giusti, A. J. Chem. Soc., Dalton Trans 1993, 409.
(33) (a) Yukawa, Y.; Igarashi, S.; Yamano, A.; Sato, S. J. Chem. Soc.,
Chem. Commun. 1997, 711. (b) Brechin, E. K.; Harris, S. G.; Parsons,
S.; Winpenny, R. E. P. J. Chem. Soc., Dalton Trans. 1997, 1665. (c)
Sanz, J. L.; Ruiz, R.; Gleizes, A.; Lloret, F.; Faus, J.; Julve, M.; Borra´s-
Almenar, J. J.; Jouraux, Y. Inorg. Chem. 1996, 35, 7384. (d) Oushoorn,
R. L.; Boubekeur, K.; Batail, P.; Guillou, O.; Kahn, O. Bull. Soc. Chim.
Fr. 1996, 133, 777. (e) Blake, A. J.; Cherepanov, V. A.; Dunlop, A.
A.; Grant, C. M.; Milne, P. E. Y.; Rawson, J. M.; Winpenny, R. E. P.
J. Chem. Soc., Dalton Trans. 1994, 2719. (f) Andruh, M.; Ramade,
I.; Codjovi, E.; Guillou, O.; Kahn, O.; Trombe, J. C. J. Am. Chem.
Soc. 1993, 115, 1822. (g) Guillou, O.; Bergerat, P.; Kahn, O.;
Bakalbassis, E.; Boubekeur, K.; Batail, P.; Guillot, M. Inorg. Chem.
1992, 31, 110.
(3A2g f T2g) at ca. 850 nm is obviously split.
(e) [YbNi2(tam)2(H2O)]ClO4‚2.58H2O (9). The [YbNi2-
(tam)2(H2O)]+ cation in complex 9 was found to be very similar
in the solid state to the Dy(III) analogue. The C1 symmetry
cation contains an Yb(III) ion with two [Ni(tam)]- units
coordinated to it. The Yb(III) ion in 9 has a typical six-
coordination sphere with a distorted octahedral geometry, being
bonded to two [Ni(tam)]- ligands. As in 6, one [Ni(tam)]- is
tridentate and the other bidentate with respect to Yb(III); the
sixth coordination site is occupied by a water molecule. All of
the phenolato functions are deprotonated; only five of them,
however, are bridging between the Ni(II) and Yb(III) ions. One
of the phenolate O atoms is not bonded to the Yb(III) ion. Each
[tam]3- ligand encapsulates a Ni(II) ion via its three amine and
three phenolato functions; hence, each nickel(II) ion has
approximately octahedral geometry. The distances between Ni-
(II) and Yb(III) are 2.9081(8) Å (Yb(1)-Ni(1)) and 3.2702(7)
Å (Yb(1)-Ni(2)), which are comparable to the distances
between Dy and Ni in 6. The Yb-O bond lengths, average of
2.212(4) Å for the Ni(1) ligand and 2.196(4) Å for the Ni(2)
(34) (a) Cu-Gd ) 3.367 Å: Bencini, A.; Benelli, C.; Caneschi, A.; Carlin,
R. L.; Dei, A.; Gatteschi, D. J. Am. Chem. Soc. 1985, 107, 8128. (b)
Cu-Gd ) 3.347 Å: Bencini, A.; Benelli, C.; Caneschi, A.; Dei, A.;
Gatteschi, D. Inorg. Chem. 1986, 25, 572.
(35) Figgis, B. N. Introduction to Ligand Fields; Interscience: New York,
1966.
(31) Shannon, R. D., Acta Crystallogr., Sect. A 1976, 32, 751.

516 Inorganic Chemistry, Vol. 39, No. 3, 2000
Xu et al.
the range 300-7 K provides clear evidence of antiferromagnetic
exchange between the Yb(III) and the Ni(II) ions in this
compound. The exchange coupling in 9 is stronger than that in
6, leading to the general conclusion that the strength of dn-fn
coupling between Ni(II) and lanthanide ions is determined, at
least in part, by the size of the lanthanide ion, increasing with
decreasing size. Further examples are needed to confirm this.
Unfortunately, we are unaware of a theoretical treatment of a
system such as this one that would allow us to model the
behavior in order to obtain a quantitative result for the strength
of the exchange interaction. The nature of the dn-fn interactions
observed here contrasts with that reported for the Cu(II)-Ln-
(II) systems, where either antiferromagnetic or ferromagnetic
exchange may be observed depending on the fn configura-
tion.36,37
Figure 7. Temperature dependence of the magnetic moments of 2, 6,
and 9 shown on a per mole of LnNi2 basis.
The magnetic moment of 6 at 300 K is 11.9 µB. This moment,
µ
DyNi , arises from the contributions of one Dy(III) ion and two
2
Conclusions
Ni(II) ions. Assuming µNi ) 3.14 µB (as determined for 2) and
employing eq 1, we calculate µDy ) 11.0 µB as the contribution
The greater geometric flexibility of amine phenol ligands, as
compared to their Schiff base analogues, allowed for the
formation of coaggregated d- and f-block metal ion complexes.
This was highlighted by the stabilization of complexes of the
type [LnM2L2]+ having a range of lanthanide(III) ions by the
ligand tam3- (M ) Ni(II) in this paper; studies of other first-
row transition metal ions are in progress). The solid-state
structures of three of these complexes revealed that the ligand
tam3- encapsulated Ni(II) ions in an octahedral geometry,
resulting in the formation of a [Ni(tam)]- moiety which could
be incorporated as a ligand for lanthanide(III) ions. The choice
of counterion was critical in determining the nature of the
resulting complex; the bicapped [LnM2(tam)2]+ units were only
isolated if perchlorate was employed. When a more strongly
coordinating counterion, such as NO3-, was chosen the resulting
complex was a capped species, i.e., [ErNi(tam)(NO3)3]-.38
Variable-temperature magnetic studies indicated that antiferro-
magnetic exchange coupling between Ni(II) and a lanthanide
ion increased with decreasing size of the lanthanide ion.
2 1/2
µDyNi ) (µDy2 + 2µNi
]
(1)
2
from the Dy(III) ion. This value is in excellent agreement with
the value of 10.6 µB calculated from the formula µJ ) g[J(J +
1)]1/2 for the H15/2 ground state of Dy(III). Because of low
6
ligand field potentials and strong spin-orbit couplings in the
case of lanthanide ions, this formula is expected to apply to
Dy(III).35 The magnetic moment of 6 remains essentially
constant from 300 to about 22 K, below which it decreases to
a low of 7.76 µB at 2 K. This decrease in moment at low
temperatures is in part due to zero-field splitting of Ni(II) as
seen for 2; however, the effect is much too large to be due only
to this phenomenon. Employing the values 2.96 µB for µNi at 2
K (obtained from the 2 K data for 2) and 11.0 µB for µDy, we
calculate µDyNi ) 11.8 µB, a value far in excess of the observed
2
7.76 µB. This observation and the fact the temperature depen-
dence of the moment in 6 extends over a slightly larger
temperature range than that seen for 2 suggest there may be
some antiferromagnetic coupling in the former compound. Any
coupling must, however, be weak since only very low temper-
ature data are affected by it.
Acknowledgment. We gratefully acknowledge the NSERC
(Canada) for the provision of operating grants (R.C.T., C.O.),
the EPSRC (U.K.) for support of the crystallography unit
(M.B.H.), and Dr. P. Caravan for helpful discussions.
Supporting Information Available: Complete tables of crystal-
lographic data, atomic coordinates, U(eq) values, bond lengths, bond
angles, anisotropic thermal parameters, hydrogen atom coordinates,
torsion angles, nonbonded contacts, and least-squares planes. This
material is available free of charge via the Internet at http://pubs.acs.org.
The magnetic moment of 9, µYbNi , is 6.28 µB at 300 K.
2
Employing 3.13 µB for µNi, as above, we calculate µYb ) 4.44
µB. This compares with the theoretical µJ ) 4.50 µB for the
2F7/2 ground state of Yb(III). In contrast to the situation for 2
and 6, the magnetic moment of 9 decreases measurably on
lowering the temperature over the entire range of temperatures
studied. It varies from 6.28 µB at 300 K to 5.50 µB at 7 K (Figure
7). Below 7 K, the rapid drop in moment to 5.06 µB at 2 K is,
as before, at least partly due to zero-field splitting in Ni(II).
The temperature variation of the magnetic moment of 9 over
IC991171B
(36) Andruh, M.; Ramade, I.; Codjovi, E.; Guillou, O.; Kahn, O.; Trombe,
J. C. J. Am. Chem. Soc. 1993, 115, 1822.
(37) Costes, J.-P.; Dahan, F.; Dupuis, A.; Laurent, J.-P. Chem.sEur. J.
1998, 4, 1616.
(38) Read, P. W.; Orvig, C. Unpublished results.