Synthesis and structural characterization of some potassium complexes of some bis(phenolate) ligands and some novel heterobimetallic binuclear arrays formed with trivalent lanthanoid ions

Article abstract of DOI:10.1002/zaac.200700442

The structural characterizations of the potassium complexes of a pair of dianionic bis(phenolate) ligands, {L^R = [^-OC ₆H₂(2,4-Bu^t)(6-CH₂)] ₂NCH₂CH₂R} R = NMe₂, OMe, crystallized from 1,2,-dimethoxyethane (DME) are recorded, showing them to take the binuclear form [K₂L^R(DME)₃]. A pair of neutral binuclear heterobimetallic isotypic complexes are defined with ytterbium(III), with phenol, as sodium salts, of the form [Yb(L ^R)(OPh)₂Na(DME)(HOPh)], and a further array with samarium(III), of the (partially protonated) form [Sm(L^OMe) ₂-Na(OH₂)]. A further complex, [Na(DME) ₃][Yb(*L^py)₂], results from an unusual ligand reduction by an ytterbium(II) species to give a new dianionic Schiff base ligand which is coordinated to ytterbium(III) {*L^py = ^-OC₆H₂(2,4-Bu^t)(6-CH=N-CH-2-C ₆H₄N)}.

Full text of DOI:10.1002/zaac.200700442

DOI: 10.1002/zaac.200700442
Synthesis and Structural Characterization of Some Potassium Complexes of
Some Bis(phenolate) Ligands and Some Novel Heterobimetallic Binuclear
Arrays Formed with Trivalent Lanthanoid Ions
Pascal I. Bindaa, Ewan E. Delbridgea,*, Divine T. Dugaha, Brian W. Skeltonb and Allan H. Whiteb
a Grand Forks, North Dakota, 58202/USA, University of North Dakota, Chemistry Department
b Crawley 6009/Western Australia, The University of Western Australia, School of Biomedical, Biomolecular and Chemical Sciences,
Chemistry M313
Received June 12th, 2007, revised August 24th, 2007.
Abstract. The structural characterizations of the potassium
complexes of a pair of dianionic bis(phenolate) ligands, {LR
[ϪOC6H2(2,4-But)(6-CH2)]2NCH2CH2R}
NMe2, OMe,
samarium(III), of the (partially protonated) form [Sm(LOMe)2-
Na(OH2)]. A further complex, [Na(DME)3][Yb(*Lpy)2], results
from an unusual ligand reduction by an ytterbium(II) species to
give a new dianionic Schiff base ligand which is coordinated to
ytterbium(III) {*Lpy ϭ ϪOC6H2(2,4-But)(6-CHϭN-CH-2-C6H4N)}.
ϭ
R
ϭ
crystallized from 1,2,-dimethoxyethane (DME) are recorded,
showing them to take the binuclear form [K2LR(DME)3]. A pair
of neutral binuclear heterobimetallic isotypic complexes are defined
with ytterbium(III), with phenol, as sodium salts, of the form
Keywords: Lanthanoids; Alkali metals; Phenolates; Ytterbium;
Samarium
[Yb(LR)(OPh)2Na(DME)(HOPh)], and
a
further array with
Introduction
There has been a recent upsurge of interest in the synthesis
of lanthanoid complexes supported by non-Cp ligands.
Specifically, non-lanthanocene compounds containing
multidentate anionic ligands such as guanidinates [1Ϫ4], β-
diketiminates [5Ϫ8], salen [9, 10], diamides [11, 12] and bis-
(phenolate)s [13Ϫ17] are of interest (Figure 1) since they
are considered more ’chemically robust’ (i.e. they are less
susceptible to hydrolysis and are less likely to undergo li-
gand redistribution reactions) compared with their Cp
counterparts. As a result, such lanthanoid compounds have
found great utility in catalysis [14, 18, 19] and luminescence
[20, 21] studies. Among these ligand systems, lanthanoid
compounds comprising multidentate phenolate and
bis(phenolate) ligands have recently exhibited excellent
catalytic properties towards ring-opening polymerization
(ROP) reactions of cyclic esters such as lactide (LA) and ε-
caprolactone (ε-CL) [9, 14, 16Ϫ18, 22Ϫ27]. In many cases
these ligands are not easily displaced from the lanthanoid
metal center during the polymerization reaction, making
them highly valuable as stationary ’spectator ligands’. For
these reasons, the authors’ attention has focussed on synth-
Figure 1 Some non-Cp ligands used in lanthanoid synthesis.
eses of lanthanoid phenolate and bis(phenolate) com-
pounds.
To the authors’ knowledge, only two studies [13, 28] have
investigated the synthesis and complete structural studies of
anionic lanthanoid bis(phenolate)s containing alkali metal
counter ions. This class of complex (commonly referred to
as ‘ate’ complexes) has very interesting coordination chem-
istry, leading to intriguing solid state structures. Reported
herein are some recent findings concerning the syntheses
and detailed X-ray crystal structure studies of some novel
lanthanoid bis(phenolate) ‘ate’ complexes, containing so-
dium counter-ions, as well as the corresponding parent pot-
assium bis(phenolate) compounds. In addition, a highly no-
vel and unusual ytterbium(III) phenolate compound is re-
ported where the phenolate ligand has been reduced by the
initial YbII atom via a hydrogen abstraction pathway mak-
ing the initially monoanionic phenolate ligand dianionic.
* Prof. Dr. E. E. Delbridge
University of North Dakota
Chemistry Department, Stop 9024, Grand Forks ND, 58202, USA
Fax: (ϩ)1 701 777 2331
E-mail: edelbridge@chem.und.edu
Z. Anorg. Allg. Chem. 2008, 634, 325Ϫ334
 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
325

P. I. Binda, E. E. Delbridge, D. T. Dugah, B. W. Skelton, A. H. White
NMR, δ: (125.8 MHz, CD2Cl2, 298K) 30.21 (CMe3), 32.61 (CMe3), 34.24
(CMe3), 35.97 (CMe3), 54.62 (NCH2CH2O), 57.86 (NCH2CH2O), 59.35
(OCH3, DME) 71.28 (OMe), 72.36 (OCH2CH2O, DME), 75.51 (ArCH2N),
122.99 (arom-CH), 127.36 (arom-CBut), 128.16 (arom-CH), 129.48 (arom-
CBut), 136.88 (arom-CCH2N), 167.86 (arom-CO).
Experimental Section
General
The complexes described herein are air- and moisture-sensitive, such
that all manipulations were performed under nitrogen atmospheres
employing typical Schlenk line and glove box techniques. Solvents
were dried and purified by distillation under nitrogen from sodium
or potassium metal mixed with benzophenone, while deuterated sol-
vents, purchased from Cambridge Isotope Laboratory, were dried
over sodium metal or CaH2, deoxygenated and purified by vacuum
transfer. The reagents [Ln(N(SiMe3)2)2(THF)2] [29] (Ln ϭ Sm, Yb),
H2LR {LR ϭ [ϪOC6H2(2,4-But)(6-CH2)]2NCH2CH2R} (R ϭ NMe2,
[Sm(LOMe)] (5)
To a dark purple hexanes (15 mL) solution of [Sm(N(SiMe3)2)2-
(THF)2] (0.61 g, 1.00 mmol) at room temperature, H2LOMe ligand
(0.51 g, 1.00 mmol) in hexanes (10 mL) was added via a cannula
to give a black solution with black precipitate, which was stirred
overnight. The black precipitate was separated from the black solu-
tion and dried to afford 5 (0.55 g, 83 %). Mp: 189Ϫ192 °C (dec.).
C33H51NO3Sm (660.13 g/mol): C 60.07, H 7.84, N 2.24, (calc. C
60.04, H 7.79, N 2.12) %.
OMe) [30, 31] (THF ϭ tetrahydrofuran) and HLpy [32] {Lpy
ϪOC6H2(2,4-But)(CHϭN-CH2-C6H5N)} were synthesized by the
indicated reported procedures. The complexes [YbLNMe2
and
ϭ
]
2
[YbLOMe] were synthesized according to the reported literature
procedures [13]. All the other reagents were purchased from Acros
and used as received. Melting points were obtained from sealed
capillaries on a Mel-Temp apparatus and are uncorrected. IR spec-
tra (4000-450 cmϪ1) were recorded as KBr Nujol mulls on an ATI
Mattson Genesis Series FTIR Spectrometer. The 1H and 13C NMR
spectra were recorded on a Bruker AVANCE-500 NMR spec-
trometer and referenced to C6D5H or C4D7HO or CDHCl2 (1H)
and C6D6 or C4D8O or CD2Cl2 (13C). Elemental analyses (sealed
ampoules under inert atmosphere) were performed by Midwest
Microlab, Indianapolis IN.
IR (KBr, Nujol): 1764(w), 1748(w), 1599(s), 1545(w), 1411(w), 1305(m),
1264(s), 1236(w), 1199(m), 1162(m), 1132(m), 1117(m), 1067(s), 1039(s),
1001(m), 954(w), 927(w), 910(w), 877(s), 829(s), 735(s), 642(w), 608(w),
574(w), 517(m), 426(m) ν cmϪ1 1H NMR, δ: (500.1 MHz, C4D8O, 298K):
,
Ϫ8.10 (b, 18H, But), 0.02 (s, 18H, But), 0.79 (s, 4H, ArCH2N), 1.32 (b, 2H,
NCH2CH2OMe), 1.43 (b, 2H, NCH2CH2OMe), 2.38 (s, 3H, OMe), 3.14 (s,
2H, CH arom.), 4.89 (b, 2H, CH arom.); (500.1 MHz, C7D8, 378K): Ϫ2.78
(b, 1H, CH arom.), Ϫ1.67 (b, 1H, CH arom.), Ϫ1.28 (b, 1H, CH arom.),
0.24 (s, 2H, ArCH2N), 0.87 (s, 2H, ArCH2N), 1.25 (b, 2H, NCH2CH2OMe),
1.35 (b, 2H, NCH2CH2OMe), 1.48 (b, 18H, 2ϫBut), 1.70 (s, 3H, OMe), 2.00
(s, 9H, But), 2.32 (s, 1H, CH arom.), 3.61 (s, 9H, But).
[Yb(LNMe2)(OPh)] (6)
A DME (10 mL) solution of phenol (0.26 g, 2.77 mmol) was added
to a stirred DME (15 mL) solution of [YbLNMe2]2 (hexane) (1.00 g,
0.67 mmol) and heated at 50 °C for 11 h to give a yellow solution
after which time the DME was removed to yield a yellow solid.
Light yellow microcrystals of 6 (0.95 g, 81 %) were grown at room
temperature from a hexanes solution. From one reaction pale yel-
low single crystals of [Yb(LNMe2)(OPh)2Na(DME)(HOPh)] (9)
were grown and subjected to a single crystal X-ray diffraction
study. Mp: 173 °C (dec.). C40H59N2O3Yb (788.96 g/mol): C 60.19,
H 7.63, N 2.93 (calc. for no DME: C 60.90, H 7.54, N 3.55; for
one DME: C 60.12, H 7.91, N 3.19) %.
Synthesis of Complexes
[K2(LNMe2)(DME)3] (1)
KH (0.31 g, 7.73 mmol) was slowly added to a stirred 1,2-di-
methoxyethane (DME) (40 mL) solution of H2LNMe2 (2.0 g,
3.87 mmol) at room temperature. Stirring was then continued 12 h
to afford colourless crystals of 1 (3.0 g, 91 %). Mp: 200 °C (dec.).
C46H84 K2N2O8 (871.38 g/mol): C 63.80, H 9.41, N 3.52 (calc. C
63.41, H 9.72, N, 3.21) %.
IR (KBr, Nujol) 2360(w), 1600(w), 1538(w), 1326(s), 1303(s), 1257(m),
1230(m), 1199(m), 1157(m), 1122(s), 1079(s), 1022(m), 979(m), 848(w),
IR (KBr, Nujol): 2854(s), 1592(w), 1335(w), 1203(w), 1161(w), 1076(s),
1022(s), 924(w), 875(w), 802(s), 760(m), 694(w), 579(w), 528(w), 451(w) ν
806(w), 732(w), 674(w), 640(w), 574(w), 507(w) ν cmϪ1 1H NMR, δ:
;
(500.1 MHz, CD2Cl2, 298K) 1.21 (s, 18H, But), 1.38 (s, 18H, But), 1.51 (s,
6H, NMe2), 2.01 (t, 2H, J 7.1, NCH2CH2NMe2), 2.60 (t, 2H, J 7.1
NCH2CH2NMe2), 2.99 (d, 2H, J 11.3, ArCH2N), 3.32 (s, 18H, OCH3,
DME), 3.56 (s, 12H, OCH2CH2O, DME), 4.03 (d, 2H, J 11.3, ArCH2N),
6.98 (s, 2H, Ar), 7.16 (s, 2H, Ar); 13C NMR, δ: (125.8 MHz, CD2Cl2, 298K)
30.17 (CMe3), 32.54 (CMe3), 34.23 (CMe3), 35.96 (CMe3), 44.88 (NMe2),
54.61 (NCH2CH2NMe2), 60.01 (OCH3, DME) 63.58 (NCH2CH2NMe2),
65.71 (ArCH2N), 72.46 (OCH2CH2O, DME), 123.00 (arom-CH), 127.76
(arom-CBut), 127.93 (arom-CH), 130.17 (arom-CBut), 136.93 (arom-
CCH2N), 167.33 (arom-CO).
cmϪ1
.
[Yb(LOMe)(OPh)] (7)
Using similar procedure to that described for the synthesis of 6,
treatment of [YbLOMe] (0.50 g, 0.73 mmol) with phenol (0.10 g,
1.10 mmol) in DME (25 mL) with heating at 50 °C for 11 h af-
forded a green yellow solution. Solvent removal and recrystalliza-
tion from hexanes gave crystals of 7 (0.48 g, 85 %). From one reac-
tion pale green yellow single crystals of [Yb(LOMe)(OPh)2Na-
(DME)(HOPh)] (10) were grown and subjected to a single crystal
X-ray diffraction study. Mp: 171-173 °C (dec.) C39H56NO4Yb
(775.91 g/mol): C 59.70, H 7.55, N 1.59 (calc. for no DME: C
60.37, H 7.27, N 1.81; for one DME C 59.64, H 7.68, N, 1.62) %.
[K2(LOMe)(DME)3] (2)
Using a similar procedure for the synthesis of complex 1, treatment
of KH (0.31 g, 7.73 mmol) with H2LOMe (1.98 g, 3.87 mmol) in
40 mL of DME afforded 2 (3.1 g, 92 %) as pale yellow crystals.
Mp: 180 Ϫ 182 °C (dec.). C45H81K2NO9 (858.34 g/mol): C 63.32,
H 9.28, N, 1.57 (calc. C 62.97, H 9.51, N 1.63) %.
IR KBr, nujol) 2858(s), 1770(w), 1592(m), 1296(s), 1265(s), 1203(m),
1165(m), 1076(s), 1022(s), 910(w), 833(m), 802(m), 759(m), 694(m), 602(w),
579(w), 528(w), 455(w) ν cmϪ1
.
IR (KBr, Nujol): 1600(w), 1330(s), 1295(s), 1257(m), 1230(m), 1199(m),
1130(s), 1095(s), 1022(s), 983(m), 925(w), 883(m), 856(m), 806(m), 732(m),
640(w), 578(w), 509(w) ν cmϪ1 1H NMR, δ: (500.1 MHz, CD2Cl2, 298K)
;
[Sm(LOMe)(OPri)] (8)
1.27 (s, 18H, But), 1.42 (s, 18H, But), 2.66 (t, 2H, J 4.9, NCH2CH2O), 2.79
(s, 3H, OMe), 3.17 (d, 2H, J 12.1, ArCH2N), 3.28 (s, 18H, OCH3, DME)
3.38 (t, 2H, J 4.9, NCH2CH2O), 3.54 (s, 12H, OCH2CH2O, DME), 3.96 (d,
2H, J 12.1, ArCH2N), 6.92 (d, 2H, J 2.7 Ar), 7.07 (d, 2H, J 2.7 Ar); 13C
Isopropanol (1.0 mL, 13.1 mmol) was added to a black DME
(15 mL) solution of complex 5 (0.30 g, 0.45 mmol) at room tem-
326
www.zaac.wiley-vch.de
 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2008, 325Ϫ334

Potassium Complexes of Some Bis(phenolate) Ligands
perature via a syringe and stirred overnight. The solution gradually
turned into a pale yellow solution after which time all volatiles
were removed in vacuo, to yield a yellow powder of 8 (0.21 g,
61 %). From one reaction pale yellow single crystals of
[Sm(LOMe)2Na(OH2)] (11) were grown and subjected to a single
crystal X-ray diffraction study. Mp: 190Ϫ194 °C (dec.).
C36H58NO4Sm (719.22 g/mol): C 59.67, H 8.11, N 2.02 (calc. C
60.12, H 8.13, N 1.95) %.
‘T’min/max ϭ 0.79. 2θmax ϭ 50°; Nt ϭ 44216, N ϭ 10924 (Rint ϭ
0.073), No ϭ 4096; R1 ϭ 0.081, wR2 ϭ 0.30, S ϭ 0.96. Η∆ρmaxΗ ϭ
0.27 e AϪ3. T ca. 298 K.
˚
Variata. DME group (2) was modelled as disordered over two sets
of sites, as also was t-butyl group (15) (the latter rotationally dis-
ordered about its pendant bond), the components of each being
modelled with site occupancies 0.5, constrained with idealized geo-
metries. The CH2CH2NMe2 pendant was also modelled as dis-
ordered, component occupancies refining to 0.701(2) and comp-
lement (constrained geometries). Refinement used the SHELXL 97
program [34]; reflection weights being (σ2(F2) ϩ (0.170P)2)Ϫ1 (P ϭ
IR (KBr, Nujol): 1772(w), 1603(m), 1412(w), 1379(m), 1360(w), 1323(w),
1260(s), 1202(m), 1163(w), 1093(s), 1023(s), 931(w), 911(w), 876(s), 803(s),
740(s), 645(w), 521(s), 424(m) ν cmϪ1 1H NMR, δ: (500.1 MHz, C6D6,
;
298K): 1.34 (s, 3H, OMe), 1.45 (b, 18H, But), 1.60 (b, 18H, But), 1.69 (s, 4H,
2ϫArCH2N), 1.83 (b, 1H, NCH2CH2OMe), 2.13 (b, 6H, CH3CHCH3), 2.32
(m, 1H, CH3CHCH3), 3.03 (s, 1H, NCH2CH2OMe), 3.30 (s, 1H,
NCH2CH2OMe), 3.53 (s, 1H, NCH2CH2OMe), 7.52 (s, 2H, CH arom.), 8.01
(s, 2H, CH arom).
2
2
Fo ϩ 2Fc )/3).
[K2(LOMe)(DME)3] (2). C45H81K2NO9, M ϭ 858.5. Monoclinic,
˚
space group P21/n, a ϭ 10.747(2), b ϭ 31.129(6), c ϭ 15.701(3) A,
3
Ϫ3
˚
β ϭ 95.990(2)°, V ϭ 5224 A . Dc (Z ϭ 4 dimers) ϭ 1.091 g cm
.
ϭ
ϭ
µMo ϭ 0.23 mmϪ1; specimen: 0.42 x 0.30 x 0.23 mm; ‘T’min/max
0.77. 2θmax ϭ 50°; Nt ϭ 33395, N ϭ 9261 (Rint ϭ 0.052), No
[YbIII(Lpy)2]؉[YbIII(*Lpy)2]؊ (12)
A deep orange hexanes solution (10 mL) of [Yb(N(SiMe3)2)2-
(THF)2] (0.64 g, 1.00 mmol) was treated with a yellow hexanes
7480; R ϭ 0.052, Rw ϭ 0.12 (nw ϭ 1.2); S ϭ 1.06. Η∆ρmaxΗ ϭ 0.84 e
Ϫ3. T ca. 153 K.
˚
A
solution (9 mL) of HLpy {Lpy
ϭ
ϪOC6H2(2,4-But)(6-CHϭN-CH2-
Variata. DME group (3) was modelled as disordered over two sets
of sites, occupancies refining to 0.839(4) and complement (isotropic
displacement parameter refinement for C, O of the latter).
2-C6H4N)} (0.65 g, 2.00 mmol) at room temperature to form an
instant dark blue solution. The solution was stirred for 4 h and
dark blue crystals of 12 (0.93 g, 57 %) were obtained from hexanes
and appropriate amount of DME. From one reaction dark
[Yb(LR)(OPh)2Na(DME)(HOPh)] R ؍ NMe2 (9), OMe (10); are
isotypic (the structure of the 9 being determined on a capillary
mounted specimen at 298 K (the crystals breaking up at 170 K, the
temperature at which 10 was studied)), monoclinic, space group
P21/n, Z ϭ 4.
blue single crystals of [Na(DME)3][Yb(*Lpy)2] (13) {*Lpy
ϭ
ϪOC6H2(2,4-But)(CHϭN-CH-C6H5N)} were grown and subjected
to single crystal X-ray diffraction study. Mp: 239 °C.
a
C84H106N8O4Yb2 (1637.90 g/mol): C 60.03, H 7.20, N 6.18, Yb
21.61 (calc. C 61.60, H 6.52, N 6.84, Yb 21.13) %.
IR (KBr, Nujol) 1542(w), 1508(w), 1199(w), 1169(m), 1088(s), 1018(s),
(a) Complex 9: C56H80N2NaO7Yb, M ϭ 1089.3. a ϭ 10.6226(9),
933(m), 802(s), 752(w), 686(w) ν cmϪ1
.
3
˚
˚
b ϭ 32.144(3), c ϭ 17.075(2) A, β ϭ 104.839(1)°, V ϭ 5636 A .
Dc ϭ 1.284 g cmϪ3. µMo ϭ 1.72 gmϪ3; specimen: 0.45 x 0.30 x
0.20 mm; ‘T’min/max ϭ 0.81. 2θmax ϭ 57°; Nt ϭ 51272, N ϭ 13933
(Rint ϭ 0.023), No ϭ 12606; R ϭ 0.034, Rw ϭ 0.066 (nw ϭ 35); S ϭ
Structure determinations
Ϫ3
˚
0.98. Η∆ρmaxΗ ϭ 1.7 e A
.
Full spheres of CCD area-detector diffractometer data were meas-
ured (Bruker AXS instrument, ω-scans; monochromatic Mo Kα
radiation; λ ϭ 0.71073 A), yielding Nt(otal) reflections, these merging
Variata. The pendant methyl groups of the NMe2 group, as well as
the associated methylene group, were modelled as disordered over
pairs of sites occupancies refining to 0.793(8) and complement.
˚
to N unique (Rint cited) after ’empirical’/multiscan absorption cor-
rection (proprietary software), No with F > 4σ(F) being considered
’observed’. Full matrix least squares refinement on F2 (all data,
Xtal 3.7 program system [33], neutral atom complex scattering fac-
tors) refined anisotropic displacement parameter forms for the
non-hydrogen atoms, hydrogen atom inclusion following a riding
model. Conventional residuals R, Rw are cited (reflection weights:
(σ2(F2) ϩ nwF2)Ϫ1. Pertinent results are given below and in the
Tables and Figures. Individual variations in procedure are noted as
’variata’. Crystallographic data for the structures have been de-
posited with the Cambridge Crystallographic Data Centre, CCDC
657332-657337. Copies of the data can be obtained free of charge
on application to The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (Fax: int.codeϩ (1223) 336-033; e-mail
for inquiry: fileserv@ccdc.cam.ac.uk; e-mail for deposition:
deposit@ccdc.cam.ac.uk).
(b) Complex 10: C55H77NNaO8Yb, M ϭ 1076.3. a ϭ 10.727(1), b ϭ
3
˚
˚
32.388(4), c ϭ 17.325(2) A, β ϭ 106.598(2)°, V ϭ 5768 A . Dc ϭ
1.239 g cmϪ3. µMo ϭ 1.68 gmϪ3; specimen: 0.52 x 0.44 x 0.32 mm;
‘T’min/max ϭ 0.79. 2θmax ϭ 57°; Nt ϭ 51664, N ϭ 14071 (Rint
ϭ
0.028), No ϭ 11994; R ϭ 0.047, Rw ϭ 0.084 (nw ϭ 25); S ϭ 0.95.
Ϫ3
˚
Η∆ρmaxΗ ϭ 2.4 e A
.
Variata. C(2) of the (CH2)2OMe pendant of the LOMe ligand was
modelled as disordered over a pair of sites, occupancies set at 0.5
after trial refinement. The hydroxyl hydrogen atom of the phenol
ligand was located in difference maps.
[(LOMeH)(LOMe)3Sm2Na(OH2)]0.5 (11). C66H103.5N2Na0.5O6.5Sm,
M ϭ 1190.9. Monoclinic, space group P21/n, a ϭ 14.5300(9), b ϭ
3
˚
˚
31.929(3), c ϭ 15.589(2) A, β ϭ 112.573(1)°, V ϭ 6678 A . Dc (Z ϭ
4) ϭ 1.184 g cmϪ3. µMo ϭ 0.93 mmϪ1; specimen: 0.25 x 0.17 x
0.10 mm; ‘T’min/max ϭ 0.77. 2θmax ϭ 50°; Nt ϭ 58906, N ϭ 11766
(Rint ϭ 0.062), No ϭ 9586; R ϭ 0.073, Rw ϭ 0.13 (nw ϭ 55); S ϭ
Crystal/refinement data
[K2(LNMe2)(DME)3] (1). C46H84K2N2O8, M ϭ 871.4. Monoclinic,
1.11. Η∆ρmaxΗ ϭ 2.7 e AϪ3. T ca. 170 K.
˚
space group P21/c (C52h No. 14), a ϭ 21.651(10), b ϭ 16.462(10),
3
c ϭ 17.329(10) A, β ϭ 95.279(10)°, V ϭ 6150 A . Dc (Z ϭ 4) ϭ
0.941 g cmϪ3. µMo ϭ 0.19 mmϪ1; specimen: 0.22 x 0.16 x 0.12 mm;
Variata. The complex is essentially [Sm(LOMe)2Na(OH2)]. The
(CH2)2OMe pendant on ligand 2 is modelled as disordered over a
˚
˚
Z. Anorg. Allg. Chem. 2008, 325Ϫ334
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327

P. I. Binda, E. E. Delbridge, D. T. Dugah, B. W. Skelton, A. H. White
pair of sites (occupancy 0.5), the first component coordinated to
the sodium atom, the second component (primed) directed other-
wise, (corresponding to a vacant Na site and contacting N(21),
considered, ad hoc, to be protonated). A further residue was mod-
elled as a water molecule oxygen atom (occupancy 0.5) associated
with the sodium atom (no associated hydrogen atoms located). The
model thus approximates to [Sm(LOMe)2Na(OH2)][Sm(LOMe)-
(LOMeH)]. Disordered components were refined with isotropic dis-
placement parameters.
materials for a variety of heteroleptic and homoleptic lan-
thanoid compounds with compounds 1 and 2 being em-
ployed in metathesis reactions involving lanthanoid halides
such as YbI2(THF)2 [13]. Compounds 3Ϫ5 (for which de-
tailed syntheses and reactivity were recently reported [13]
for 3 and 4), can be readily treated with easily reduced
alcohols to form a variety of heteroleptic compounds [13],
to yield [Ln(LR)(ORЈ)] Ln ϭ Yb, RЈ ϭ Ph, R ϭ NMe2 (6)
or OMe (7); Ln ϭ Sm, RЈ ϭ Pri, R ϭ OMe (8).
Compound 5, the samarium analogue of 3 and 4, exhibits
similar solution properties to these ytterbium compounds
where, in donor solvents, such as tetrahydrofuran (THF), it
exists as a monomer and in non-donor solvents (e.g. tolu-
ene) a dimeric structure is prevalent. This is consistent with
the previously reported X-ray crystal structure of 3 [13]
which has a dimeric structure (crystallized from hexanes)
[LnLR]2 where the C2 symmetry of the bis(phenolate) ligand
is lost upon bridge formation.
While the experimental procedures for 6 and 7 have been
reported previously by the authors, their details are reiter-
ated here since two novel and highly unusual compounds
(9, 10) were derived from these reactions. Compounds 3Ϫ8
were routinely synthesized as part of a catalytic study in-
vestigating the ROP capabilities of these catalyst precursors
towards ε-caprolactone [13]. During particular syntheses of
compounds 6Ϫ8, single crystals were grown from each reac-
tion mixture, which was believed to be that of the respective
target complex. However, X-ray crystallographic studies
demonstrated the formation of three remarkable new com-
pounds, [Yb(LR)(OPh)2Na(DME)(HOPh)] R ϭ NMe2 (9);
OMe (10) derived from compounds 6 and 7 respectively,
and [Sm(LOMe)2Na(OH2)] (11) which is derived from com-
pound 8 (See below for detailed single crystal X-ray struc-
ture discussions). Compounds 9 and 10, which have the
same formulation and ligand ratio, are ytterbium(III)
bis(phenolate) ‘ate’ complexes where essentially a routine
NaOPh component has been combined with a neutral
[Yb(LR)OPh] complex. It is believed that the origin of the
sodium component was from contamination of the
[Ln(N(SiMe3)2)2(THF)2] starting material. It has been
[Na(DME)3][Yb(*Lpy)2] (13). C54H82N4NaO8Yb, M ϭ 1111.3. Or-
14
thorhombic, space group Pbcn (D , No. 60), a ϭ 15.683(2), b ϭ
2h
21.369(2), c ϭ 17.168(2) A, V ϭ 5754 A . Dc ϭ 1.283 g cmϪ3
.
ϭ
3
˚
˚
µMo ϭ 1.68 gmϪ3; specimen: 0.25 x 0.15 x 0.11 mm; ‘T’min/max
0.77. 2θmax ϭ 60°; Nt ϭ 53093, N ϭ 7351 (Rint ϭ 0.052), No
ϭ
4698; R ϭ 0.047, Rw ϭ 0.092 (nw ϭ 75); S ϭ 0.96. Η∆ρmaxΗ ϭ 2.1 e
Ϫ3. T ca. 170 K.
˚
A
Variata. The sodium and ytterbium atoms are disposed on crystal-
lographic 2-axes; DME ligand(1) was modelled as disordered over
pairs of sites, occupancies 0.5, associated C, O displacement par-
ameter forms isotropic.
Results and Discussion
Synthesis ؊ Lanthanoid and Potassium
bis(phenolate) Complexes
The readily prepared H2LR ligands [35, 36] (R ϭ NMe2,
OMe) were deprotonated with two equivalents of potassium
hydride in DME to yield [K2LR(DME)3] where R ϭ NMe2
(1); OMe (2) (DME ϭ 1,2-dimethoxyethane). Both of these
compounds have been characterized fully and 1H NMR
spectroscopic and elemental analyses are consistent with the
formulations elucidated by X-ray crystallographic studies
(See Experimental Section for details). These two com-
pounds represent convenient starting materials for the syn-
thesis of lanthanoid bis(phenolate) ‘ate’ complexes such as
[K(DME)2][YbIII(LOMe)2] [13].
Alternatively, H2LR ligands can be treated with one
equivalent of [Ln(N(SiMe3)2)2(THF)2] to give [LnLR] Ln ϭ
Yb, R ϭ NMe2 (3) or OMe (4); Ln ϭ Sm, R ϭ OMe (5)
(Scheme 1). Compounds 1Ϫ5 represent excellent starting
Scheme 1 Synthesis of lanthanoid and potassium phenolate complexes
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Potassium Complexes of Some Bis(phenolate) Ligands
reported [37] that inadequate and non-rigorous extraction
of [Ln(N(SiMe3)2)2(THF)2] from NaI can lead to its
inclusion to give Na[Ln(N(SiMe3)2)3]. Compound 11
[Sm(LOMe)2Na(OH2)], also containing sodium, presumably
from the same source, i.e. [Ln(N(SiMe3)2)2(THF)2], has a
residue modelled as a coordinated water molecule which
presumably could arise from the presence of adventitious
water. As with 9 and 10, compound 11 is a samarium
bis(phenolate) ‘ate’ complex with a sodium counter-ion.
observed for the samarium(II) compounds Ϫ the more
powerful of the divalent reducing agents. In the present sys-
tem, however, deprotonation of the the methylene carbon
occurs, resulting in the formation of sp2 hybridized carbon
(C(20) in Figure 5 Ϫ see below). Due to the highly para-
magnetic nature of ytterbium(III), NMR studies were not
feasible. Indeed the absence of any intelligible 1H NMR
spectroscopic data provided evidence, albeit indirect, for the
oxidation of ytterbium(II). Further evidence to support this
claim was provided by the X-ray crystal structure of the
related compound [Na(DME)3][Yb(*Lpy)2] 13, which crys-
tallized from one reaction mixture of 12. As with many of
the bis(phenolate) structures discussed above, the presence
of sodium can be readily accounted for by insufficient puri-
fication of the [Yb(N(SiMe3)2)2(THF)2] starting material,
where sodium becomes entrained as Na[Ln(N(SiMe3)2)3]
[37].
Synthesis of Ytterbium Reduced Phenolate Complex
Treatment of two equivalents of the Schiff base phenol
HLpy [32]1) with divalent [Yb(N(SiMe3)2)2(THF)2] did not
produce the expected product as a result of a typical proteo-
lytic ligand exchange reaction (Scheme 2). Rather, the ytter-
bium(II) atom was able to reduce the Schiff base ligand in
a unique fashion, resulting in methylene deprotonation and
formation of a dianionic ligand. Ligand redistribution leads
to formation of a unique ytterbium(III) phenolate complex
(Scheme 2, 12) containing the mono- and di-anionic li-
gands. From one reaction, crystallization led to the iso-
lation of 13 as indentified by an X-ray study (see below).
While there is some precedent for divalent lanthanoid com-
pounds reducing Schiff bases [38], typically involving CϭN
reduction followed by ligand coupling through the imine
carbon atom, this current type of reduction is unpre-
cedented. Furthermore, imine reductions are usually only
Crystal Structures
The results of single crystal X-ray structure determinations
on specimens of the potassium salts of H2LR (R ϭ NMe2,
OMe) from DME solution are consistent with their formu-
lation as DME tri-solvates of the salts of the doubly
charged ligand/dianion (i.e. the pro-ligand deprotonated at
the two phenolic residues), both taking the form of neutral
binuclear molecules [K2LR(DME)3] (1) and (2), one such
entity, devoid of crystallographic symmetry, comprising the
asymmetric unit of the structure in each case; the molecules
are similar in aspect, albeit the structures are not isotypic.
In each case, the precision of the determination is somewhat
degraded by disorder; nevertheless, this is essentially restric-
ted to substituent or pendant saturated chain confor-
mations with little impact on the form of the molecular co-
res. The two potassium atom environments differ within
each complex, but display many similarities between the
two complexes. They are presented in Table 1 with two
complexes displayed in Figure. 2, showing, despite their
considerable formal similarity, considerable differences in
the conformations and dispositions of the DME solvent
chelate, and the pendant groupings.
The potassium atoms K(2) are six-coordinate in both
complexes, well-removed from octahedral geometry, the
N∧O chelate angles being ca. 70°, with the O-K-O angle
about 90°, the O∧N∧O ligand string comprising a quasi-
fac tridentate ligand. The oxygen atoms of DME ligand 2
comprise a chelate donor, occupying a further pair of cis-
sites in the K(2) coordination sphere. The associated K-O
˚
distances are rather similar (ca. 2.9 A), although the two
values are greater in the LNMe2 complex, 1, cf. their LOMe
counterparts (the opposite of what might be expected to re-
sult from the different temperatures of the two determi-
nations), with K-O(201) greater than K-O(202) in each case
(the former distance being quasi-trans to the central N-do-
nor of the oligodentate ligand). The last coordination site is
occupied by the OMe or NMe2 pendant of the oligodentate
ligand, the OMe group being strongly bound with the K-O
distance comparable to the K-phenolic-O distances,
Scheme 2 Syntheses of ytterbium complexes possessing reduced
phenolate ligands.
1) The Lpy ligand is defined as {Lpy ϭ ϪOC6H2(2,4-But)(6-CHϭN-
CH2-2-C6H4N)} containing a methylene carbon (bolded) whereas
the *Lpy ligand is defined as {*Lpy
ϭ
ϪOC6H2(2,4-But)(6-CHϭN-
CH-2-C6H4N)} where the methylene carbon atom has been depro-
tonated.
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329

P. I. Binda, E. E. Delbridge, D. T. Dugah, B. W. Skelton, A. H. White
Table 1 Potassium atom environments in [K2(LR)(DME)3] R ϭ
NMe2 (1), OMe (2). Values for complex 1 lie below those for com-
˚
plex 2; r/A is the potassium-ligand atom distance; other entries in
the matrix are the angles (degrees) subtended at the potassium
atom by the relevant atoms at the head of the row and column.
K(1)
r
O(22)
O(101)
O(102)
O(301/301Ј)
O(302/302Ј)
O(12) 2.623(2) 99.16(6) 95.16(6) 123.08(6) 93.62(6), 116.1(2) 84.0(1), 75.5(5)
2.628(2) 89.60(7) 103.6(1) 161.2(1) 103.1(1) 102.2(1)
147.46(8) 88.16(6) 133.21(6), 115.1(3) 76.8(1), 79.2(5)
O(22) 2.622(2)
2.662(3)
O(101) 2.810(2)
2.927(5)
101.0(1) 95.8(1) 158.4(1)
59.60(6) 73.97(6), 83.2(3)
57.7(2) 92.9(2)
102.8(1)
133.8(1), 132.8(5)
144.7(1)
O(102) 2.747(2)
2.842(4)
121.20(7), 110.8(2) 151.1(1), 159.4(5)
77.8(2)
94.2(6)
O(301) 2.809(2)
O(301Ј) 2.73(1)
2.913(4)
Ϫ , 24.8(3)
60.0(1), 60.9(5)
, 61.7(6)
57.9(2)
Ϫ
O(302) 2.780(5)
O(302Ј) 2.86(3)
2.977(4)
Ϫ , 56.8(3)
Ϫ , 8.6(5)
Ϫ
˚
K(1)···K(2) are 3.441(1), 3.816(3) A.
K(2)
r
O(12)
O(22)
N,O(3) O(201) O(202) O(302/302Ј)
N(1)
2.911(2) 68.86(9) 71.83(5) 63.02(6) 152.35(6) 108.03(6) 121.68(9), 124.4(5)
2.897(3) 73.12(7) 74.06(7) 64.32(1) 160.8(1) 114.8(1)
O(12) 2.718(2)
2.778(2)
O(22) 2.701(2)
2.722(3)
94.94(5) 90.48(6) 115.09(6) 165.34(6) 74.2(1), 71.2(5)
85.34(6) 109.5(1) 112.7(1) 171.3(1)
128.80(6) 132.02(6) 97.60(6) 68.15(9), 74.9(5)
127.9(1) 123.7(1) 100.0(1)
89.34(6) 75.74(6) 159.0(1), 152.3(5)
96.9(2) 72.6(1)
O(3)
2.714(2)
N(3) 3.127(6)
O(201) 2.865(2)
2.983(5)
60.68(6) 84.4(1), 80.5(5)
58.6(1)
O(202) 2.819(2)
2.906(4)
117.6(1), 119.6(5)
O(302) 3.240(5)
O(302Ј) 3.04(3)
Ϫ
Ϫ, 6.9(5)
˚
2.662(3) A), the angles between them differ by nearly ten
degrees (being larger in the LOMe complex), reflecting the
similar difference found in O(12)-K(2)-O(22), the latter con-
trary to the difference that might be anticipated to be conse-
quent on any quasi-trans-influence contingent on the differ-
ence in the strengths of the K(2)-O,N(3) interactions. All
K(1)-O(n02)(DME) distances in the LNMe2 complex are ap-
preciably longer than their counterparts in the LOMe com-
plex, despite the smaller O(12)-K(1)-O(22) angle in the lat-
ter.
Figure 2 (a,b) Projections of [K2(LR)(DME)3] (1) and (2) with a
common setting of chirality, normal to their central K(µ-O)2K core
planes. t-Butyl methyl groups omitted for clarity.
whereas the K-NMe2 distance is much longer. In the LOMe
complex, O(302) also has a distant approach not evident in
the LNMe2 complex, more likely a consequence of the prox-
imity of K(1) (to which it is bound) rather than any ap-
proach to bond formation. With the angles O(12)-K(2)-
O(22) ca. 90°, the pairs of phenolic oxygen atoms may then
act as further chelate donors, to K(1), forming four-mem-
bered KO2K rings which are the cores of the two molecules.
The K(1) atom environments are also six-coordinate, well-
removed from the octahedral norm, their coordination
spheres being tris-bidentate, by virtue of the chelation of
the remaining pair of DME ligands, these being of very
small ’bite’ (ca. 60°). Although K(1)-O(12),O(22) are
closely similar throughout both complexes (2.622(2)-
With the two dianionic ligands LOMe and LNMe2, the re-
sults of the single crystal X-ray studies define the pair of
heterobimetallic (Na/Yb) agglomerates 9, 10, complex but
well-defined and isotypic, with disorder found only in the
peripheral methylene groups of the pendant strings of
the LR ligands. The complexes are of the form
[Yb(LR)(OPh)2Na(DME)(HOPh)] R ϭ NMe2 (9), OMe
(10); the residual phenolic proton is well-defined in each
case, being hydrogen-bonded to an adjacent phenoxide-oxy-
OMe
˚
gen atom, O,H(301)···O(201) 2.675(5), 1.9 A (est.) (L
complex); 2.664(4), 1.8 A (est.) (L
NMe2
˚
complex). A projec-
tion of the LOMe aggregate is given in Figure 3 with metal
330
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Potassium Complexes of Some Bis(phenolate) Ligands
Table 2 The metal atom environments in [Yb(LR)(OPh)2Na-
(DME)(HOPh)] R ϭ NMe2 (9), OMe (10). Values for complex 9
lie below those for complex 10, (presentation as in Table 1).
atom environment parameters presented in Table 2. The in-
teractions of the ytterbium atoms with the LR ligands are
similar, and similar to those found in the solvated K2L
arrays about the K(2) atoms. The atomic radius of the ytter-
bium atoms is greatly diminished relative to that of the pot-
assium atoms. The coordination environments are still six-
coordinate, but more nearly octahedral, with M-N more
conspicuously longer than M-O, and the angle between the
phenolic oxygen donor atoms now splayed more towards
linearity, so that the aspect of the O∧N∧O string formed
with the central nitrogen atom N(1) is more nearly ’fac’,
rather than ’mer’ as previously, with the phenoxide-oxygen
atoms now incapable of coordinating the (now smaller) alk-
ali metal atom. This is accomplished by completion of the
six-coordinate array by the coordination, not of a DME
chelating ligand, but by a pair of unidentate phenoxide li-
gands (compensating the additional charge of the ytter-
bium(III) cf. the potassium(I) atom), the ’equatorial’ phen-
oxide oxygen then, with O(22) of the L ligand, chelating
the group I (sodium) counter-ion, again forming a four-
membered MO2MЈ ring, this time heterobimetallic. Despite
only trivial differences in the associated Yb-O and O-Yb-O
parameters of this ring in the ytterbium atom environments,
and also in their sodium counterparts, the Na···Yb dis-
(a) The sodium atoms
Atom
r
O(101)
O(301)
O(401)
O(402)
O(22)
2.390(3)
2.416(3)
2.318(3)
2.295(3)
2.629(5)
2.546(4)
2.327(5)
2.338(4)
2.361(7)
2.380(4)
74.7(1)
75.2(1)
87.9(1)
85.5(1)
88.5(1)
88.6(1)
170.2(2)
166.4(1)
102.8(2)
96.4(1)
101.6(2)
105.2(1)
104.0(2)
108.4(1)
131.(2)
136.0(1)
140.3(2)
135.0(1)
70.3(2)
O(101)
O(301)
O(401)
O(402)
70.1(1)
(b) The ytterbium atoms
Atom
N(1)
r
O(12)
O(22)
O/N(3)
69.6(1)
O(101)
95.6(1)
O(201)
2.456(3)
2.452(3) 81.0(1) 82.8(1)
79.61(1) 81.4(1)
164.5(1)
166.9(1)
103.4(1)
103.8(1)
95.4(1)
93.3(1)
95.3(1)
71.3(1) 92.2(1)
86.2(1) 96.8(1)
162.7(1) 88.0(1) 91.8(1)
89.1(1) 83.0(1)
O(12)
O(22)
2.107(3)
2.099(2)
2.175(3)
2.187(3)
2.418(3)
2.575(3)
160.9(1)
92.4(1) 83.0(1)
O(3)
N(3)
164.2(1)
163.4(1) 96.4(1)
99.1(1)
˚
tances in the two complexes differ by nearly 0.2 A (Table
O(101) 2.137(3)
2.155(3)
99.8(1)
2). The coordination environments of the sodium atoms are
sparse, the five-coordinate arrays being made up of the
DME solvent (chelating, and, like the MO2MЈ ring chelate,
of small ’bite’) and a (’solvent’) non-deprotonated phenol
ligand, the Na-O distance associated with the latter being
long.
O(201) 2.144(3)
2.157(3)
˚
Na···Yb are 3.402(2), 3.419(2) A.
bium complexes. The fifth and sixth coordination sites are
occupied by the phenolic oxygen atoms of a second LOMe(2)
ligand, these providing the bridging atoms for the forma-
tion of a further four-membered MO2MЈ ring, M, MЈ ϭ
Na, Sm by chelating the associated sodium atom, the orien-
tation of that ring now being ’axial’ rather than ’equatorial’
cf. the lanthanoid/LOMe(1) environment (Figure 4, Table 3).
The sodium atom is again five-coordinate, the additional
donor atoms being the central nitrogen atom of LOMe(2),
and the pendant methoxy oxygen atom, together with a
residue modelled as a water molecule oxygen atom. One
formula unit, devoid of crystallographic symmetry, com-
prises the asymmetric unit of the structure.
Formulation as [Sm(LOMe)2Na(OH2)], although satisfy-
ing charge balance requirements in terms of the usual
mono- and triply-charged metal atoms and doubly depro-
tonated ligands, sits uncomfortably with refinement behav-
iour. The pendant group of the oligodentate ligand is dis-
ordered, with components of the disorder lying unrealist-
ically close to the sodium atom; the latter, moreover, to-
gether with the residue modelled as the water molecule
oxygen atom, have high displacement parameters, becoming
reasonable by allowing the site occupancies to refine, these
becoming close to 0.5 at which value they were fixed. We
thus postulate, that in the absence of the sodium atom and
the water molecule, either the central nitrogen atom N(21)
of LOMe(2) or the phenolic oxygen atom O(23) becomes
Figure 3 Projection of [Yb(LOMe)(OPh)2Na(DME)(HOPh)] (10),
normal to the Yb(µ-O)2Na core plane.
The last complex of this form (11), defined for the
MMЈ ϭ Na/Sm combination, is more tentative in its formu-
lation, but nevertheless of considerable interest. Here, the
lanthanoid atom is again six-coordinate, interacting with
LOMe(1) in the manner previously described for the ytter-
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331

P. I. Binda, E. E. Delbridge, D. T. Dugah, B. W. Skelton, A. H. White
protonated, the associated hydrogen component (e.g.
H(21ЈN)) contacting the oxygen atom of the second (reori-
ented) component of the disordered pendant (N(21),
˚
H(21ЈN)···O(23Ј) 2.96(1), 2.6 A (est.)).
The results of the study of the final complex 13 are
consistent with its formulation as the ionic array
[Na(DME)3][Yb(*Lpy)2] (Figure 5, Table 4 with Lpy and
*Lpy as defined above; also see Scheme 2). One half of the
formula unit comprises the asymmetric unit of the struc-
ture, each metal atom lying on a crystallographic two-fold
axis, relating the two ligands of the anion, the cation en-
vironment being an aggregate of a pair of ordered DME
chelating groups, related by the two-fold axis (ligands 2);
ligand 1 (and its image) are disordered, in total making up
a complex disordered composite in which Na-O (DME) dis-
˚
tances, range closely between 2.38(2)-2.44(1) A, compare
well with the usual norm.
Figure 4 Projection of [Sm(LOMe)(LOMe/HLOMe){Na(OH2)}0.5],
normal to the Sm(µ-O)2Na core plane. t-Butyl methyl groups omit-
ted for clarity.
Table
3
The metal atom environments in ‘Sm2(LOMe)4H-
Na(OH2)’ (11).
(a) The sodium atom
Atom
r
O(212)
81.2(3)
O(222)
O(23)
O(1)
N(21)
O(212)
O(222)
O(23)
O(1)
2.316(9)
2.373(7)
2.320(7)
2.25(2)
81.2(3)
85.9(2)
74.3(5)
121.1(6)
139.2(5)
147.7(7)
128.9(7)
109.0(7)
78.9(8)
2.30(3)
(b) The samarium atom
Atom
r
O(112)
74.6(2)
O(122)
O(13)
O(212)
O(222)
N(11)
2.647(5)
2.207(5)
2.250(5)
2.537(5)
2.240(4)
2.246(5)
76.2(2)
150.7(2)
66.02(2)
81.9(2)
84.9(2)
155.3(2)
105.7(2)
100.1(2)
89.4(2)
113.8(2)
94.2(2)
99.0(2)
176.0(2)
90.9(2)
O(112)
O(122)
O(13)
O(212)
O(222)
Figure 5 Projection of the anion of [Na(DME)3][Yb(*Lpy)2] 13,
normal to the crystallographic 2-axis, which lies horizontal in the
page.
˚
Na···Sm is 3.249(5); in the absence of Na, H(21ЈN)···O(23Ј) is 2.6 A (see text).
Table 4 The ytterbium atom environment in [Na(DME)3][Yb(*Lpy)2] (13) (see text). Primed atoms are related by the crystallographic 2-axis
which passes through the ytterbium atom. Counterpart values are given for [K(DME)2][Yb(LOMe)2] [13] and [K(THF)3][Yb(LNMe2)2] [39].
Atoms
[Na(DME)3][Yb(*Lpy)2]
[K(DME)2][Yb(LOMe)2]
[K(THF)3][Yb(LNMe2)2]
˚
Distances/A
Yb-N(1)
Yb-O(12)
2.409(5)
2.083(5)
2.334(5)
2.528(4), 2.508(4)
2.174(4), 2.171(2)
2.116(3, 2.132(3)
2.538(3), 2.499(3)
2.160(2), 2.189(2)
2.112(2), 2.128(2)
Yb-N/O(22)
Angles/°
N(1)-Yb-O(12)
76.7(2)
69.4(2)
170.8(2)
98.0(2)
118.2(2)
139.7(2)
109.5(2)
96.5(2)
81.4(2)
78.7(1), 79.2(1)
77.6(1), 77.7(1)
177.2(1)
99.3(1), 98.9(1)
103.7(1), 104.7(1)
155.9(2), 156.9(1)
88.0(1)
77.18(8), 78.90(9)
77.97(9), 78.22(9)
176.98(8)
99.53(9), 100.60(8)
103.19(9), 104.62(9)
154.74(8), 156.95(9)
87.01(8)
N(1)-Yb-N/O(22)
N(1)-Yb-N(1Ј)
N(1)-Yb-O(12Ј)
N(1)-Yb-N/O(22Ј)
O(12)-Yb-N/O(22)
O(12)-Yb-O(12Ј)
O(12)-Yb-N/O(22Ј)
N/O(22)-Yb-N/O(22Ј)
94.1(1), 91.5(5)
95.7(1)
94.26(8), 92.68(9)
95.73(9)
In the present [Na(DME)3]ϩ cation, Na-O range between 2.38(2)-2.44(1) A.
˚
332 www.zaac.wiley-vch.de
 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2008, 325Ϫ334

Potassium Complexes of Some Bis(phenolate) Ligands
The charge-balancing component required is arguably a
singly charged counter-ion containing ytterbium(III) with
a pair of crystallographically equivalent dianionic N∧N∧O
ligand donors. Excluding the t-butyl groups, the overall
skeleton of the ligand is quite closely planar (χ2 4307; maxi-
oxide-O distances, both of these contracting in the present,
with some very substantial changes in associated angles.
The structure forms layers, normal to c, lying between z ϭ
0Ϫ1/2 (etc.).
˚
mum atom deviation C(14) 0.252(8) A; maximum deviation
Acknowledgment. Financial support from ND EPSCoR program is
gratefully acknowledged.
˚
within the tridentate OCCCNCCN string N(1) 0.144(6) A),
although the dihedral angle between the peripheral C6/C5N
aromatic ring planes is 12.8(2)°; the deviation of the ytter-
bium atom from the overall component chelate ring planes
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the string C(11)-C(10)-N(1)-C(20)-C(21) are 1.459(9),
1.300(8), 1.368(9), 1.368(10) A with angles at C(10), N(1),
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˚
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˚
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K[Yb(LNMe2)2]·3THF. In both cases, a neutral aggregate
with quasi-2 symmetry is formed, the potassium atom being
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N-Yb-N, cf. counterpart O-Yb-O angles. Also of interest
are the changes in Yb-central-N and Yb-common-phen-
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 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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www.zaac.wiley-vch.de
 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2008, 325Ϫ334