Homoleptic anionic aryloxolanthanoid(III) complexes

Article abstract of DOI:10.1039/a608062f

Several anionic complexes of lanthanoid metals with the 2,6-diphenylphenolate ligand have been synthesized and their room-temperature single-crystal structures determined. In novel reactions of anhydrous LnCl₃ (Ln = Nd or Er) with NaOC₆H₃Ph₂-2,6·0.5thf (thf = tetrahydrofuran) in 1,3,5-tri-tert-butylbenzene at 300°C, complexes of the type [Na{Ln(OC₆H₃Ph₂2,6)₄}] were obtained. Crystallisation of [Na{Nd(OC₆H₃Ph₂-2,6)₄}] from bis(2-methoxyethyl) ether (diglyme) or 1,2-dimethoxyethane (dme) afforded the corresponding solvated complexes [Na(diglyme)₂][Nd(OC₆H₃Ph₂-2,6) ₄] or [Na(dme)₃][Nd(OC₆H₃Ph₂-2,6) ₄] respectively, and from an analogous reaction for Ln = Er [Na(diglyme)₂][Er(OC₆H₃Ph₂-2,6) ₄] was isolated. The complexes [Na(diglyme)₂]-[Ln(OC₆H₃Ph ₂-2,6)₄] (Ln = Nd or Er) are isomorphous. Their structures revealed novel discrete homoleptic tetrakis(aryloxo)lanthanoid(III) anions, well separated from the solvated sodium cations. Annealing the reaction mixture for the synthesis of [Na{Nd(OC₆H₃Ph₂-2,6)₄}] at 120°C gave single crystals of a monomeric bimetallic in which the sodium ion is encapsulated by three aryloxide oxygens as well as by three phenyl rings of the phenolate ligand, and neodymium is surrounded by a highly distorted tetrahedral arrangement of aryloxide oxygens. There are also intramolecular π-Ph-M (M = Na or Nd) interactions.

Full text of DOI:10.1039/a608062f

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Homoleptic anionic aryloxolanthanoid(III) complexes
Glen B. Deacon,*,a Tiecheng Feng,a Peter C. Junk,a Brian W. Skeltonb and Allan H. Whiteb
a
Department of Chemistry, Monash University, Clayton, Vic. 3168, Australia
b Department of Chemistry, University of Western Australia, Nedlands, W.A. 6907, Australia
Several anionic complexes of lanthanoid metals with the 2,6-diphenylphenolate ligand have been synthesized and
their room-temperature single-crystal structures determined. In novel reactions of anhydrous LnCl3 (Ln = Nd or
Er) with NaOC6H3Ph2-2,6ؒ0.5thf (thf = tetrahydrofuran) in 1,3,5-tri-tert-butylbenzene at 300 ЊC, complexes of the
type [Na{Ln(OC6H3Ph2-2,6)4}] were obtained. Crystallisation of [Na{Nd(OC6H3Ph2-2,6)4}] from bis(2-methoxy-
ethyl) ether (diglyme) or 1,2-dimethoxyethane (dme) afforded the corresponding solvated complexes
[Na(diglyme)2][Nd(OC6H3Ph2-2,6)4] or [Na(dme)3][Nd(OC6H3Ph2-2,6)4] respectively, and from an analogous
reaction for Ln = Er [Na(diglyme)2][Er(OC6H3Ph2-2,6)4] was isolated. The complexes [Na(diglyme)2]-
[Ln(OC6H3Ph2-2,6)4] (Ln = Nd or Er) are isomorphous. Their structures revealed novel discrete homoleptic
tetrakis(aryloxo)lanthanoid() anions, well separated from the solvated sodium cations. Annealing the reaction
mixture for the synthesis of [Na{Nd(OC6H3Ph2-2,6)4}] at 120 ЊC gave single crystals of a monomeric bimetallic in
which the sodium ion is encapsulated by three aryloxide oxygens as well as by three phenyl rings of the phenolate
ligand, and neodymium is surrounded by a highly distorted tetrahedral arrangement of aryloxide oxygens. There
are also intramolecular π-Ph᎐M (M = Na or Nd) interactions.
The use of sterically bulky ligands in preparing lanthanoid
tris(aryloxides) and tris(alkoxides) provides examples of low-
co-ordinate species,1,2 metal-organic chemical vapour
deposition precursors,1a,e,3 and intra-2f,g,4 and inter-molecular 4,5
π-bonded complexes. Similar approaches have been used for
low-co-ordinate aryloxolanthanoid() species.6 Such com-
plexes, including solvent-free derivatives, are now well estab-
lished 1 and are of considerable continuing interest. However,
structurally characterised compounds containing low-
co-ordinate, homoleptic anionic complexes of the type
[Ln(OR)n](3Ϫn)Ϫ (R = aryl or alkyl) are limited to [{K[Ln(OC6H3-
Pri2-2,6)4]}n] 1 (Ln = La, Nd, Er or Lu),7a–c [{Cs2[La(OC6H3Pri2-
2,6)5]}n] 27d and [Na{Nd(OC6H3Ph2-2,6)4}] 3,7d the latter being
the topic of a preliminary communication of our current work.
In each of these complexes the alkali-metal ion is involved in π-
arene and oxygen bridging interactions with the anion, result-
ing in bimetallic complex structures of either one-dimensional
chains (1, Ln = Nd, Er or Lu),7a,b two-dimensional sheets (1,
Ln = La),7c an extended three-dimensional structure (2)7d or a
monomer (3).7d These complexes reveal a common feature in
lanthanoid chemistry, viz. the retention of an alkali-metal
reagent from the metathesis synthetic pathway in the lantha-
noid co-ordination sphere.
LnCl3(anhydrous) + NaOR•0.5 thf
(i)
(ii)
(iv)
(iii)
[Na{Nd(OR)4}]
3
[Na{Ln(OR)4}]
[Na(dme)3][Nd(OR)4]
6
(iii)
[Na(diglyme)2][Nd(OR)4]
4
[Na(diglyme)2][Er(OR)4]
5
Scheme
1
R = C6H3Ph2-2,6. (i) 1,3,5-Tri-tert-butylbenzene, 240–
300 ЊC; (ii) annealing at 120 ЊC giving single crystals; (iii) recrystallis-
ation from diglyme; (iv) recrystallisation from dme
120 ЊC [Scheme 1, step (ii)] provided single crystals in a tri-tert-
butylbenzene matrix, from which the compound was readily
extracted. Similar syntheses followed by treatment of the reac-
tion mixture with the tri- or bi-dentate co-ordinating solvents
bis(2-methoxyethyl) ether and 1,2-dimethoxyethane afforded
complexes 4–6 [Scheme 1, (iii)–(v)]. This approach has allowed
us to isolate compounds in which the co-ordinating solvent suc-
cessfully competes with co-ordination sites in the anions for
complexation of the cation (see structural section). Previous
compounds of this type were prepared in the unidentate co-
ordinating solvent tetrahydrofuran (thf), or non-co-ordinating
solvents such as toluene or pentane. In these complexes
the anions evidently offer a more favourable co-ordinating
environment for the cations.7
In this paper we report the synthesis and crystal structures
of [Na(diglyme)2][Nd(OC6H3Ph2-2,6)4]
methoxyethyl) ether], [Na(diglyme)2][Er(OC6H3Ph2-2,6)4]
4
[diglyme = bis(2-
5
and [Na(dme)3][Nd(OC6H3Ph2-2,6)4] 6 (dme = 1,2-dimethoxy-
ethane). These have discrete homoleptic aryloxolanthanoid()
anions with the alkali-metal cations separated fully from the
lanthanoid co-ordination sphere. We also record a full account
of the synthesis and crystal structure of the unsolvated
[Na{Nd(OC6H3Ph2-2,6)4}] 3.
Infrared and UV/VIS spectra of compounds 3–6 show fea-
tures expected for the ligands and Nd3ϩ or Er3ϩ respectively.
Compound 4 behaves as a 1:1 electrolyte in methylene chloride
(see ref. 8 for characteristic values), implying that the compound
exists as discrete cations and anions in solution.
Results and Discussion
Syntheses
Structures
The key step in the synthesis of compounds 3–6 was a
metathesis reaction between anhydrous lanthanoid trichlorides
and sodium 2,6-diphenylphenolate at elevated temperature in
1,3,5-tri-tert-butylbenzene [Scheme 1, step (i)]. In the prepar-
ation of [Na{Nd(OC6H3Ph2-2,6)4}] 3 subsequent annealing at
The molecular structures of compounds 3–6 were determined
by room-temperature single-crystal studies. Pertinent bond dis-
tances and angles are shown in Tables 1–3. The determination
for compound 6 was of rather low precision due to a poor
J. Chem. Soc., Dalton Trans., 1997, Pages 1181–1186
1181

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structural features. In each case the metal exists in a slightly
distorted tetrahedral environment of four phenolate ligands
[Fig. 1(b), Table 1]. The Nd᎐O distances in 4 range from
2.175(4) to 2.207(4) Å. These are comparable with Nd᎐O in
[{K[Nd(OR)4]}n] (R = 2,6-Pri2C6H3) (average = 2.21 Å),7a,b des-
pite the presence of K᎐O᎐Nd bridging in the latter, and of
Nd᎐Oter in [Na{Nd(OC6H3Ph2-2,6)4}] 3 (2.20 Å) where the co-
ordination number of Nd may be considered to be enhanced by
π bonding of the aryl groups (below). The Nd᎐O distances are
also similar to the Nd᎐O(OC6H3Ph2-2,6) distances of 2.160(2)
to 2.233(3) Å in the four-co-ordinate [Nd(OC6H3Ph2-2,6)3(thf)]
and slightly longer than those in the three-co-ordinate
[Nd(OC6H3Ph2-2,6)3] [2.140(3)–2.193(5) Å], but again, in both
these complexes, the formal co-ordination number of neo-
dymium is higher due to neodymium–π-aryl interactions.2g
They also lie between 〈Nd᎐Oter〉 (2.122 Å) and 〈Nd᎐Obr〉 (2.211
Å) of [{Nd(OR)3}2] (R = 2,6-Pri2C6H3) where the formal co-
ordination number of neodymium is six owing to η6-Ph᎐Nd
bridging.5 The Nd᎐O distances are longer than the average
terminal Nd᎐O distances (2.05–2.174 Å) found in alkoxide
complexes [Nd2(OCHPri2)6(thf)2],9 [Nd2(OCHPri2)6(py)2] (py =
pyridine),9 [Nd2(OCHPri2)6(µ-dme)],9 [Nd6(OPri)17Cl],10 [Nd-
(OCBut2CH2PMe2)3],11 [Nd5O(OPri)13(HOPri)2],12 [Nd4(OCH2-
But)12]13 and [Nd(OCBut3)3(MeCN)2],14 suggesting greater
bulkiness of the OC6H3Ph2-2,6 ligand vis-à-vis the alkoxides.
The Er᎐O distances in compound 5 [2.068(6) to 2.090(6) Å] are
shorter than the Nd᎐O distances in 4 to an extent reasonably
consistent with the differences in ionic radii between Nd3ϩ and
Er3ϩ 15
They are also similar to those of [{K[Er(OR)4]}n]
.
(R = C6H3Pri2-2,6) [2.053(6)–2.115(6) Å,7b where oxygen
bridges K and Er, and of five-co-ordinate [Er(OR)3(thf)2]
(R = C6H3Pri2-2,6) [2.07(1)–2.09(1) Å].5a It is noteworthy that in
the homoleptic phenolato anionic complexes 4 and 5 there are
no intramolecular Ln᎐C (aryl) contacts of any significance, by
contrast with 3 (below) as well as 1 and 2.7
The structures of the cations in compounds 4 and 5 reveal a
discrete sodium ion six-co-ordinated by two diglyme molecules.
The stereochemistry about the sodium centres is best described
as a distorted trigonal prism (polyhedron fitting basis16) with
O᎐Na᎐O angles ranging from 68.7(2) to 165.4(2)Њ for 4 and
68.4(3) to 167.9(3)Њ for 5. This arrangement has been previously
2Ϫ
observed in [Na(diglyme)2][Lu(C5H5)2(C14H10)]17 (C14H10
anthracene dianion) and [Na(diglyme)2]2[C20H12] (C20H12
=
=
2Ϫ
perylene dianion),18 where the O᎐Na᎐O angles range from
69.0(2) to 163.2(2) and from 68 to 157Њ respectively. The Na᎐O
distances [2.337(5)–2.401(5) for 4, 2.343(7)–2.406(8) Å for 5]
are similar to those in previous examples of [Na(diglyme)2]ϩ
ions, where the average Na᎐O distance is 2.39 Å in [Na-
(diglyme)2]2[C20H12],18 2.35
Å
in [Na(diglyme)2][Mn2-
(CO)6(CF3CNNNN)3]19 and 2.40 Å in the foregoing lutetium
complex.17
Fig. 1 Structure of [Na(diglyme)2][Nd(OC6H3Ph2-2,6)4] 4. Compound
5 is isostructural. (a) The cation, (b) the anion
While complexes 4–6 are a new class of low-co-ordinate,
homoleptic aryloxolanthanoid anions, and there are no analo-
gous homoleptic anionic alkoxolanthanoid derivatives, it
should be noted that two tetra(alkanethiolato)lanthanoid()
anions have been structurally authenticated.20 In addition, the
water-soluble anionic lanthanoid catecholates Na5[Gd-
(C6H4O2)4]ؒ19.2H2O and Na6[Ln(C6H4O2)3]2ؒ20H2O (Ln = Gd
or Ho), can be regarded as high-co-ordinate homoleptic
anionic aryloxolanthanoid complexes.21 In these cases the high-
ly negatively charged environment provided by the small bite
chelating aryloxide ligands stabilises the complexes to
hydrolysis, in dramatic contrast to the extreme water sensitivity
of the present complexes. This contrast in properties is more
striking since substraction of the ionic radius for seven- or
eight-co-ordinate (as appropriate) Gd3ϩ from the Gd᎐O dis-
tances, gives ca. 1.34–1.38 Å, comparable with the range 1.31–
1.35 Å for water-sensitive 4 and 5, and both are larger than the
range (1.26–1.28 Å) derived from Ln᎐OR distances of low-
co-ordinate neutral lanthanoid aryloxides.2f,g,h,22
quality, poorly diffracting, decomposing specimen and the
structure is not discussed in detail.
Discrete homoleptic anionic complexes. Compounds 4 and 5
¯
are isostructural and crystallise in the triclinic space group P1
with one formula unit in the asymmetric unit existing as dis-
crete [Na(diglyme)2]ϩ cations and [Ln(OC6H3Ph2-2,6)4]Ϫ anions
(Fig. 1). The determination for 6 likewise clearly indicated the
presence of discrete [Na(dme)3]ϩ and [Nd(OC6H3Ph2-2,6)4]Ϫ
ions. These are the first examples of low-co-ordinate, homo-
leptic aryloxolanthanoid() anions existing separate from
their counter ions. The few previous examples of such com-
plexes have structures where the cations are involved in
O-co-ordination and/or π-arene intractions with the anion
(Introduction).7
The anions found in compounds 4 and 5 have very similar
1182
J. Chem. Soc., Dalton Trans., 1997, Pages 1181–1186

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Table 1 Lanthanoid environments (distances in Å, angles in Њ)
(a) [Na{Nd(OC6H3Ph2-2,6)4}] 3 [values for molecule 1 (3a) followed by
those for molecule 2 (3b)]
O(11)᎐Nd
O(21)᎐Nd
O(12)᎐Nd
O(22)᎐Nd
O(13)᎐Nd
O(23)᎐Nd
O(14)᎐Nd
O(24)᎐Nd
C(1166) ؒ ؒ ؒ Nd
C(2166)᎐Nd
C(1222)᎐Nd
C(2222)᎐Nd
C(1462)᎐Nd
C(2462)᎐Nd
2.244(5)
2.278(4)
2.236(5)
2.257(5)
2.236(4)
2.199(6)
2.208(4)
2.181(6)
[3.34(1)]*
3.233(7)
3.246(7)
3.049(9)
3.131(9)
3.157(6)
O(11)᎐Nd᎐O(12)
O(21)᎐Nd᎐O(22)
O(11)᎐Nd᎐O(13)
O(21)᎐Nd᎐O(23)
O(12)᎐Nd᎐O(13)
O(22)᎐Nd᎐O(23)
O(11)᎐Nd᎐O(14)
O(21)᎐Nd᎐O(24)
O(12)᎐Nd᎐O(14)
O(22)᎐Nd᎐O(24)
O(13)᎐Nd᎐O(14)
O(23)᎐Nd᎐O(24)
81.8(2)
80.2(2)
88.1(2)
91.6(2)
87.8(2)
92.4(2)
125.7(2)
132.9(2)
122.5(2)
126.3(2)
134.9(1)
120.9(2)
(b) [Na(diglyme)2][Ln(OC6H3Ph2-2,6)4] [Ln = Nd 4 or Er 5 (in square
brackets)]
O(1)᎐Nd
O(2)᎐Nd
O(3)᎐Nd
O(4)᎐Nd
2.175(4)
[2.068(6)]
2.207(4)
[2.090(6)]
2.176(4)
[2.088(6)]
2.191(4)
[2.080(6)]
O(1)᎐Nd᎐O(2)
O(1)᎐Nd᎐O(3)
O(2)᎐Nd᎐O(3)
O(1)᎐Nd᎐O(4)
O(2)᎐Nd᎐O(4)
O(3)᎐Nd᎐O(4)
108.1(1)
[109.0(2)]
113.6(1)
[112.7(2)]
101.7(1)
[102.9(2)]
111.7(1)
[110.5(2)]
115.4(1)
[114.0(2)]
106.0(1)
[107.6(2)]
* Considered non-bonding.
[Na{Nd(OC6H3Ph2-2,6)4}]. The crystal structure of [Na{Nd-
(OC6H3Ph2-2,6)4}] 3 reveals two independent, but closely
related monomeric molecules 3a, 3b (Fig. 2); 3a was displayed
in simpler form in the preliminary communication.7d Each neo-
dymium is co-ordinated by the oxygens of one terminal [O(n4)]
and three bridging [O(n1–n3)] (Nd᎐O᎐Na) ligands (n = 1 or 2)
in a highly distorted tetrahedral array [O᎐Nd᎐O 80.2(2)–
134.9(1)Њ], while the sodium is surrounded by three bridging
oxygen and three phenyl groups, one from each of the bridging
OC6H3Ph2-2,6 ligands. The three encapsulating phenyl groups
not only block association through intermolecular interactions,
but also allow intramolecular π-Ph᎐Na interactions (below).
This is in contrast to reported examples of M3Ϫn[Ln(OR)n]
(R = 2,6-Pri2C6H3) complexes, all of which have polymeric
structures where the alkali-metal cations are involved in inter-
molecular O-co-ordination and/or π-arene interactions with the
anions.7 While the structures of the two independent molecules
in 3 appear very similar, there are significant differences upon
close inspection. The most notable is in the sodium environ-
ment. In 3a the sodium is co-ordinated by three aryloxide oxy-
gens at 2.343(6), 2.614(7) and 2.722(5) Å, whereas in 3b there
are two close contacts at 2.337(7) and 2.438(7) Å and a much
longer Na ؒ ؒ ؒ O separation of 3.183(6) Å. Bridging Na᎐O᎐Ln
distances have been reported from 2.298(4) to 2.842(5) Å,
though these incorporate µ-, µ3- and µ4-O binding.23 In this
context it is difficult to defend Na ؒ ؒ ؒ O(23) [3.183(6) Å] as
bonding, except from the viewpoint of the similar topology of
3a and 3b and the similarity of the NdO4 environments. Other
more subtle differences between these molecules emerge from
consideration of the Na᎐π-Ph interactions.
Fig. 2 Structure [Na{Nd(OC6H3Ph2-2,6)4}] 3, (a) molecule 1 (3a), (b)
molecule 2 (3b). 20% Thermal ellipsoids are shown for the non-
hydrogen atoms, hydrogen atoms having arbitrary radii of 0.1 Å. The
conformation of molecule 1 is portrayed in a more schematic form for
simplicity in the preliminary communication 7d
(OEt2)2}n] (average 2.91 Å, upper limit 3.0–3.1 Å),24 and Na᎐C
(Ph) of Na(Ph2CCHCPh2) (average 2.88 Å).25 Thus, in 3a, rings
12, 26 and 36 are η1, η2 and η2 bonded, whereas in 3b they are
all η2 bonded.
In molecule 3a, the neodymium is contacted by four aryl-
oxide oxygens at distances ranging from 2.208(4) to 2.244(5) Å
and two aryl carbon atoms at 3.131(9) and 3.246(7) Å respect-
ively. Intra- and inter-molecular C (Ph)᎐Nd distances in [{K-
[Nd(OR)4]}n] (R = C6H3Pri2-2,6),7a [Nd(OC6H3Ph2-2,6)3(thf)],2g
[Nd(OC6H3Ph2-2,6)3]2g and [{Nd(OR)3}2]5a (R = C6H3Pri2-2,6)
of 2.898(12)–3.183(10) Å are considered significant π-Ph᎐Nd
interactions. (For a review of such interactions see ref. 4.) For
3b the co-ordination sphere of the neodymium atom consists of
four aryloxide oxygens [2.181(6)–2.278(4) Å] and three aryl car-
bon atoms [3.049(9)–3.233(7) Å]. The arrangement of the four
aryloxide groups about the neodymium is distorted from tetra-
hedral owing to Na᎐O᎐Nd bridging of three oxygens and inter-
vention of π-Ph᎐Nd interactions. Oxygen bridging between Nd
and Na leads to small Obr᎐Nd᎐Obr angles and large Obr᎐
Nd᎐Oter angles [Table 1(a)]. π-Ph᎐Nd Interactions are accom-
modated within the large O᎐Nd᎐O angles. For molecule 3a,
Nd᎐Oter [2.208(4) Å] is similar to Nd᎐Obr (average 2.239 Å),
whereas for 3b the difference may be significant [Nd᎐Oter
2.181(6), Nd᎐Obr average 2.245 Å]. The Nd᎐Obr distances are
Of the C ؒ ؒ ؒ Na separations in molecules 3a and 3b respect-
ively, five of the former [average 2.92; range 2.814(9) to 2.99(1)
Å] and six of the latter [average 3.00; range 2.783(9)–3.11(1) Å]
are considered Na᎐π-Ph interactions. These correspond closely
to reported average Na᎐C distances (2.94 Å) for η6-Ph᎐Na
interactions in (NaOC6H4Me-4)n,23 Na᎐C(Ph) π bonding for
the unsolvated (only π-Ph bonded) sodium of [{Na2(C2Ph4)-
J. Chem. Soc., Dalton Trans., 1997, Pages 1181–1186
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Table 2 Sodium environments (distances in Å, angles in Њ)
(a) [Na{Nd(OC6H3Ph2-2,6)4}] 3 [values for molecule 1 (3a) followed by those for molecule 2 (3b)]
O(11)᎐Na
O(21)᎐Na
O(12)᎐Na
O(22)᎐Na
O(13)᎐Na
2.614(7)
2.438(7)
2.343(6)
2.337(7)
2.722(5)
C(1121) ؒ ؒ ؒ Na
C(2121)᎐Na
C(1126)᎐Na
C(2126)᎐Na
C(1261)᎐Na
C(2261)᎐Na
[3.290(1)]*
3.11(1)
2.929(9)
2.783(9)
2.99(1)
C(1266)᎐Na
C(2266)᎐Na
C(1361)᎐Na
C(2361)᎐Na
C(1362)᎐Na
C(2362)᎐Na
2.92(1)
O(11)᎐Na᎐O(12)
O(21)᎐Na᎐O(22)
O(11)᎐Na᎐O(13)
O(21)᎐Na᎐O(23)
O(12)᎐Na᎐O(13)
O(22)᎐Na᎐O(23)
72.3(2)
75.4(2)
71.4(2)
68.2(2)
75.1(2)
69.3(2)
3.046(8)
2.955(8)
2.976(9)
2.814(9)
3.023(8)
O(23) ؒ ؒ ؒ Na 3.183(6)
3.045(5)
(b) [Na(diglyme)2][Ln(OC6H3Ph2-2,6)4] [Ln = Nd 4 or Er 5 (in square brackets)]
O(1a)᎐Na
O(4a)᎐Na
O(4aЈ)᎐Na
O(1b)᎐Na
O(4b)᎐Na
O(4bЈ)᎐Na
2.383(4)
[2.342(7)]
2.396(5)
[2.379(9)]
2.401(5)
[2.381(8)]
2.337(5)
[2.401(8)]
2.366(5)
[2.406(8)]
2.347(6)
[2.368(9)]
O(1a)᎐Na᎐O(4a)
O(4a)᎐Na᎐O(4aЈ)
O(4aЈ)᎐Na᎐O(1b)
O(1b)᎐Na᎐O(4b)
O(4b)᎐Na᎐O(4bЈ)
O(1a)᎐Na᎐O(4aЈ)
O(1a)᎐Na᎐O(1b)
O(4a)᎐Na᎐O(1b)
68.7(2)
[71.3(3)]
132.4(2)
[135.4(3)]
122.0(2)
[118.4(3)]
69.7(2)
[68.4(3)]
138.5(2)
[136.4(3)]
69.4(2)
[70.6(3)]
165.4(2)
[167.9(3)]
103.4(2)
[103.1(3)]
O(1a)᎐Na᎐O(4b)
O(4a)᎐Na᎐O(4b)
O(4aЈ)᎐Na᎐O(4b)
O(1a)᎐Na᎐O(4bЈ)
O(4a)᎐Na᎐O(4bЈ)
O(4aЈ)᎐Na᎐O(4bЈ)
O(1b)᎐Na᎐O(4bЈ)
121.7(2)
[121.4(3)]
92.7(2)
[91.2(3)]
90.5(2)
[89.4(3)]
99.5(2)
[101.8(3)]
108.2(2)
[109.1(3)]
100.0(2)
[100.6(3)]
70.7(2)
[69.6(3)]
* Considered non-bonding.
four-co-ordinate Nd in [{K[Nd(OR)4]}n]7a whilst Nd᎐Oter (aver-
age 2.122 Å) are shorter than Nd᎐O of the isolated four-co-
ordinate [Nd(OC6H3Ph2-2,6)4]Ϫ anion in 4. However, π-Ph᎐Nd
interactions (η6, η1) in [Nd(OC6H3Ph2-2,6)3] do lengthen the
Nd᎐O distances [2.140(3)–2.193(5) Å] beyond what would be
expected for three-co-ordinate neodymium.
Table 3 Parameters of OC6H3Ph2-2,6 ligands: δ/Å is the deviation of
the Ln atom from the central C6 phenyl ring plane, τЊ the Ln᎐O᎐
C(1)᎐C(2) torsion, φ2, φ6/Њ the dihedral angles between the central
ring C6 plane and those of the peripheral phenyl ring planes and ΣnЊ is
the sum of the angles about the O(n) centre
Complex
The angle sums at the bridging oxygen atoms are all above
350Њ (Table 3), which indicates substantial delocalisation of the
oxygen lone pairs into the aromatic ring. Further, the C᎐O dis-
tances [1.327(8)–1.347(8) Å] are well below single bond C᎐O
lengths (1.43 Å)26 and shorter than in HOC6H3Ph2-2,6 [1.381(4)
Å].27
Parameter
3a
3b
4
5
δ1
δ2
δ3
δ4
τ1
τ2
τ3
0.17(2)
0.61(2)
0.38(2)
0.73(2)
0.23(2)
0.59(1)
0.90(1)
0.14(1)
0.10(1)
38(1)
0.61(2)
0.79(2)
0.09(1)
0.09(2)
48(2)
0.74(2)
0.16(2)
0.04(2)
Ϫ179.4(8)
28(1)
Ϫ141.9(9)
18(1)
Ϫ43(2)
80(2)
75(3)
Experimental
6(2)
Ϫ14(8)
Ϫ53(9)
τ4
φ12
φ16
φ22
φ26
φ32
φ36
φ42
173.7(6)
78.8(3)
49.2(3)
42.2(3)
54.7(4)
49.7(3)
44.8(2)
50.6(3)
46.0(3)
157.8(4)
146.4(5)
159.9(4)
155.8(6)
109.1(4)
123.2(4)
118.2(4)
83.3(2)
90.2(2)
81.0(1)
350.1
Ϫ173.1(8) Ϫ177(2)
Ϫ167(3)
2,6-Diphenylphenol was obtained from Aldrich Chemical Co.,
and anhydrous neodymium and erbium chlorides from Cerac
Incorporated, Milwaukee, WI and were used without further
purification. 1,2-Dimethoxyethane, diglyme, pentane and thf
were freshly distilled from sodium–benzophenone prior to use.
The lanthanoid complexes 3–6 are highly air- and moisture-
sensitive and all preparations were conducted under an inert
atmosphere (purified N2 or Ar) involving conventional glove-
box and Schlenk techniques. The compound NaOC6H3Ph2-
2,6ؒ0.5thf was prepared by stirring HOC6H3Ph2-2,6 (1.0 g, 4.06
mmol) and NaOH (1.5 g, 37.5 mmol) in thf (50 cm3) for 10 h
at room temperature, followed by filtration and evaporation
to dryness. The product was then dissolved in toluene and
evaporated to dryness, and the ratio of thf:NaOC6H3Ph2-2,6
determined by 1H NMR spectroscopy.
88.1(3)
58.2(3)
46.5(3)
49.3(3)
37.2(3)
44.0(3)
50.8(4)
45.3(3)
152.9(5)
144.8(6)
167.7(4)
154.3(4)
117.8(5)
119.0(5)
111.0(5)
88.8(2)
91.9(2)
73.2(2)
359.5
45.8(2)
46.8(4)
58.2(2)
49.0(2)
37.9(2)
49.3(2)
50.2(2)
50.8(2)
62.0(2)
163.4(4)
166.6(4)
177.3(4)
169.5(4)
58.8(4)
51.7(4)
38.1(4)
48.8(6)
50.2(3)
50.3(4)
62.6(4)
162.1(6)
166.1(6)
176.2(5)
171.3(6)
φ46
Ln᎐O(1)᎐C(1)
Ln᎐O(2)᎐C(2)
Ln᎐O(3)᎐C(3)
Ln᎐O(4)᎐C(4)
Na᎐O(1)᎐C(1)
Na᎐O(2)᎐C(2)
Na᎐O(3)᎐C(3)
Nd᎐O(1)᎐Na
Nd᎐O(2)᎐Na
Nd᎐O(3)᎐Na
Σ1
Preparations
Σ2
359.6
355.8
[Na{Nd(OC6H3Ph2-2,6)4}] 3. Anhydrous NdCl3 (0.10 g, 0.40
mmol), NaOC6H3Ph2-2,6ؒ0.5thf (0.46 g, 1.60 mmol) and 1,3,5-
tri-tert-butylbenzene (1.0 g, 4.05 mmol) were heated in vacuo in
a sealed tube at 240 ЊC for 3 h, at 300 ЊC for 2 h, and then
overnight at 120 ЊC, giving blue crystals of complex 3 in the
C6H3But3 matrix. The bulk solid was washed with pentane to
remove C6H3But3, and the residue extracted with toluene
(3 × 10 cm3), filtered and evaporated to dryness giving 3 (yield
92%) (Found: C, 75.5; H, 4.9; Nd, 12.35. C72H52NaNdO4
requires C, 75.3; H, 4.55; Nd, 12.55%). Infrared (Nujol, ν/cmϪ1):
Σ3
359.1
352.4
very similar to Nd᎐Obr(K) (average 2.211 Å) of [{K[Nd(OR)4]}n]
(R = 2,6-Pri2C6H3),7a whilst Nd᎐Oter are similar to Nd᎐O
[2.175(4)–2.207(4) Å] of 4. Thus, the π-Ph᎐Nd interactions
appear to have little effect on the Nd᎐Oter distances. Likewise, in
[{Nd(OR)3}2] (R = 2,6-Pri2C6H3), where there is formal six-co-
ordination for Nd because of η6-Ph᎐Nd bridging, Nd᎐Obr
(average 2.211 Å)6 is similar to Nd᎐Obr (average 2.211 Å) of
1184
J. Chem. Soc., Dalton Trans., 1997, Pages 1181–1186

View Article Online
Table 4 Crystal and refinement parametersa
[Na{Nd(OC6H3Ph2-2,6)4}] 3
C72H52NaNdO4
1148.4
[Na(diglyme)2][Nd(OC6H3Ph2-2,6)4] 4
[Na(diglyme)2][Er(OC6H3Ph2-2,6)4] 5
Formula
M
C84H80NaNdO10
1416.8
C84H80ErNaO10
1439.8
Crystal symmetry
Space group
Triclinic
P1 (no. 2)
Triclinic
P1 (no. 2)
Triclinic
P1 (no. 2)
¯
¯
¯
a/Å
b/Å
c/Å
α/Њ
21.232(6)
21.250(8)
13.912(4)
81.32(3)
80.82(2)
63.85(3)
5539
18.760(2)
15.192(5)
12.749(3)
90.97(2)
90.20(2)
92.51(2)
3629
18.67(1)
15.206(7)
12.71(1)
91.03(5)
90.55(6)
92.11(4)
3604
β/Њ
γ/Њ
U/Å3
Z
4
1.38
2
1.30
2
1.33
Dc/g cmϪ3
F(000)
2348
10.0
1470
7.8
1486
12.3
µ/cmϪ1
Crystal dimensions/mm
A*min, A*max
N
0.18 × 0.42 × 0.42
1.28, 1.48
19 462
9896
0.048
0.044
0.25 × 0.15 × 0.33
1.12, 1.19
12 505
7822
0.049
0.045
0.14 × 0.30 × 0.40
1.18, 1.36
12 634
7039
0.061
0.056
No
R
RЈb
a
¯
[Na(dme)3][Nd(OC6H3Ph2-2,6)4] 6: C84H82NaNdO10, M = 1418.8, triclinic, space group P1, a = 30.26(2), b = 17.13(1), c = 16.99(2) Å, α = 61.57(8),
β = 73.80(3), γ = 89.71(5)Њ, U = 7351 ÅϪ3, Dc (Z = 4) = 1.28 g cmϪ3; µM o = 7.7 cmϪ1, specimen 0.25 × 0.25 × 0.20 mm, 2θmax = 45Њ, N = 19 235,
No = 4326, R = 0.10, RЈ = 0.09. This is an inferior determination, recorded on a decomposing (ca. 20%) specimen, refined as pseudo-symmetric
triclinic, which, with better material, may be found to be truly of higher symmetry. Anisotropic thermal parameters were refined for Na and Nd only,
with non-hydrogen cation geometry constrained. There are two molecules in the asymmetric unit with one of the cations disposed about an inversion
centre. This particular cation was modelled as disordered over two sites. b Statistical weights.
1594m, 1577m, 1405m, 1309m, 1282s, 1256s, 1070s, 854vs, 800m,
763m, 750vs, 705vs and 600s. UV/VIS (CH2Cl2), λ/nm (ε/1
molϪ1 cmϪ1): 530 (83), 576 (84), 586 (84) and 748 (57).
dme–pentane gave blue crystals of the complex (Found: C,
70.85; H, 6.05; Nd, 10.1%. C84H82NaNdO10 requires C, 71.1; H,
5.8; Nd, 10.15%). Infrared (Nujol, ν/cmϪ1): 1596w, 1578w,
1560w, 1407m, 1308w, 1287s, 1264s, 1248w, 1082s, 859s, 745s,
702m and 600w. UV/VIS (CH2Cl2), λ/nm (ε/l molϪ1 cmϪ1):
534 (38), 580 (39), 587 (40), 593 (39) and 749 (29).
[Na(diglyme)2][Nd(OC6H3Ph2-2,6)4] 4. Anhydrous NdCl3
(0.10 g, 0.40 mmol) and NaOC6H3Ph2-2,6ؒ0.5thf (0.49 g, 1.60
mmol) were heated at 300 ЊC for 3 h in a sealed glass tube. After
cooling to room temperature, the resulting blue solid was
extracted with thf (20 cm3) and filtered. The solvent diglyme
(2 cm3) and then pentane (10 cm3) were added yielding a blue
solid and a light blue solution from which single crystals of the
complex grew over several days (total yield 93%) (Found: C,
70.8; H, 4.7; Nd, 9.75. C84H80NaNdO10 requires C, 71.2; H, 5.7;
Nd, 10.15%). Infrared (Nujol, ν/cmϪ1): 1596m, 1580m, 1496m,
1407s, 1288s, 1269m, 1244m, 1200s, 1161s (sh, br), 1135s (sh,
br), 1111vs, 1081m, 862vs, 764m, 754m, 745vs, 701vs and 600s.
UV/VIS (CH2Cl2): λ/nm (ε/l molϪ1 cmϪ1): 534 (77), 582 (78),
593 (68) and 751 (30). Λm(CH2Cl2): 22 S cm2 molϪ1 (5.31 × 10Ϫ3
mol dmϪ3).
Crystallography
Unique room-temperature diffractometer data sets were meas-
ured on an Enraf-Nonius CAD-4 diffractometer (2θ–θ scan
mode, 2θmax 50Њ; monochromatic Mo-Kα radiation, λ = 0.71073
Å; T ≈ 298 K) on capillary mounted specimens, yielding N
independent reflections, No of which with I > 3σ(I) were con-
sidered ‘observed’ and used in the large-block least-squares
refinements after Gaussian absorption correction. Anisotropic
thermal parameters were refined for the non-hydrogen atoms,
(x, y, z, Uiso
)
being constrained at estimated values. Con-
H
ventional residuals on |F |, R, RЈ are quoted at convergence.
Neutral atom complex scattering factors were employed, com-
putation using the XTAL 3.2 program system implemented by
S. R. Hall.28
Atomic coordinates, thermal parameters, and bond lengths
and angles have been deposited at the Cambridge Crystallo-
graphic Data Centre (CCDC). See Instructions for Authors,
J. Chem. Soc., Dalton Trans., 1997, Issue 1. Any request to the
CCDC for this material should quote the full literature citation
and the reference number 186/393.
[Na(diglyme)2][Er(OC6H3Ph2-2,6)4] 5. Anhydrous ErCl3 (0.11
g, 0.40 mmol) and NaOC6H3Ph2-2,6ؒ0.5thf (0.49 g, 1.60 mmol)
and 1,3,5-tri-tert-butylbenzene (1.0 g, 4.05 mmol) were heated at
280 ЊC for 3 h in a sealed glass tube. After cooling to room
temperature, the resulting pink solid was extracted with thf (20
cm3) and filtered. The solvent diglyme (2 cm3) and then pen-
tane (10 cm3) were then added yielding a pink solid and a light
pink solution from which crystals of the complex were isolated
(yield 89%) (Found: C, 69.8; H, 5.5; Er, 11.25. C84H80ErNaO10
requires C, 70.1; H, 5.6; Er, 11.6%). Infrared (Nujol, ν/cmϪ1):
1598m, 1582w, 1497w, 1411s, 1352w, 1291s, 1272w, 1200s,
1109s, 1084m, 1026m, 870s, 754w, 747s, 701s and 607w.
Acknowledgements
We gratefully acknowledge support of the work by grants from
the Australian Research Council.
[Na(dme)3][Nd(OC6H3Ph2-2,6)4] 6. Anhydrous NdCl3 (0.10 g,
0.40 mmol), NaOC6H3Ph2-2,6ؒ0.5thf (0.49 g, 1.60 mmol) and
1,3,5-tri-tert-butylbenzene (1.0 g, 4.05 mmol) were heated in
vacuo at 240 ЊC for 3 h, 300 ЊC for 2 h, then overnight at 120 ЊC,
giving a blue solid in a matrix of 1,3,5-tri-tert-butylbenzene.
After cooling to room temperature, the resulting blue
[Na{Nd(OC6H3Ph2-2,6)4}] was washed with pentane (3 × 5 cm3)
to remove 1,3,5-tri-tert-butylbenzene. Recrystallisation from
References
1 (a) D. C. Bradley, Chem. Rev., 1989, 89, 1317; (b) R. C. Mehrotra,
A. Singh and U. M. Tripathi, Chem. Rev., 1991, 91, 1287; (c)
K. G. Caulton and L. G. Hubert-Pfalzgraf, Chem. Rev., 1990, 90,
969; (d) W. J. Evans, New J. Chem., 1995, 19, 525; (e) L. G. Hubert-
Pfalzgraf, New J. Chem., 1995, 19, 727.
2 (a) D. C. Bradley, H. Chudzynska, M. B. Hursthouse, M. Motevalli
J. Chem. Soc., Dalton Trans., 1997, Pages 1181–1186
1185

View Article Online
and R. Wu, Polyhedron, 1994, 13, 1 and refs. therein; (b) M. F.
Lappert, A. Singh and R. G. Smith, Inorg. Synth., 1990, 27, 164; (c)
P. S. Coan, M. J. McGeary, E. B. Lobkovsky and K. G. Caulton,
Inorg. Chem., 1991, 30, 3570; (d) P. B. Hitchcock, M. F. Lappert
and A. Singh, J. Chem. Soc., Chem. Commun., 1983, 1499; (e)
P. B. Hitchcock, M. F. Lappert and R. G. Smith, Inorg. Chim. Acta,
1987, 139, 183; (f) G. B. Deacon, S. Nickel, P. MacKinnon and
E. R. T. Tiekink, Aust. J. Chem., 1990, 43, 1245; (g) G. B. Deacon,
T. Feng, B. W. Skelton and A. H. White, Aust. J. Chem., 1995, 48,
741; (h) G. B. Deacon, B. M. Gatehouse, Q. Shen and G. N. Ward,
Polyhedron, 1993, 12, 1289; (i) A. Sen, H. A. Stecher and A. Rhein-
gold, Inorg. Chem., 1992, 31, 473; (j) W. H. Stecher, A. Sen and
A. L. Rheingold, Inorg. Chem., 1988, 27, 1132; 1989, 28, 3280; (k)
H. Schumann, G. Kociok-Kohn and J. Loebel, Z. Anorg. Allg.
Chem., 1990, 581, 69; (l) W. J. Evans, M. A. Ansari and S. I. Khan,
Organometallics, 1995, 14, 558; (m) W. J. Evans, R. Anwander,
U. H. Berlekamp and J. W. Ziller, Inorg. Chem., 1995, 34, 3583;
(n) F. T. Edelmann, A. Steiner, D. Stalke, J. W. Gilje, S. Jagner and
M. Hakansson, Polyhedron, 1994, 13, 539.
8 P. Ugluagliati, G. Deganello, L. Busetto and U. Belluco, Inorg.
Chem., 1969, 8, 1625; W. J. Geary, Coord. Chem. Rev., 1971, 7, 81.
9 D. M. Barnhart, D. L. Clark, J. C. Huffman, R. L. Vincent and J. G.
Watkin, Inorg. Chem., 1993, 32, 4077.
10 R. A. Andersen, D. H. Templeton and A. Zalkin, Inorg. Chem.,
1978, 17, 1962.
11 P. B. Hitchcock, M. F. Lappert and I. A. MacKinnon, J. Chem.
Soc., Chem. Commun., 1988, 1557.
12 G. Helgesson, S. Jagner, O. Poncelet and L. G. Hubert-Pfalzgraf,
Polyhedron, 1991, 10, 1559.
13 D. M. Barnhart, D. L. Clark, J. C. Gordon, J. C. Huffman,
J. G. Watkin and B. D. Zwick, J. Am. Chem. Soc., 1993, 115, 846.
14 W. A. Herrmann, R. Anwander, M. Kleine and W. Scherer, Chem.
Ber., 1992, 125, 1971.
15 R. D. Shannon, Acta Crystallogr., Sect. A, 1976, 32, 751.
16 M. Johnson, J. C. Taylor and G. W. Cox, J. Appl. Crystallogr., 1980,
13, 188.
17 D. M. Roitershtein, L. F. Rybakova, E. S. Petrov, A. M. Ellern,
M. Yu. Antipin and Y. T. Struchkov, J. Organomet. Chem., 1993,
460, 39.
18 H. Bock, C. Nather, Z. Havlas, A. John and C. Arad, Angew. Chem.,
Int. Ed. Engl., 1994, 33, 875.
19 E. O. John, R. D. Willett, B. Scott, R. L. Kirchmeier and
J. M. Shreeve, Inorg. Chem., 1989, 28, 893.
20 K. Tatsumi, T. Amemiya, H. Kawaguchi and K. Tani, J. Chem. Soc.,
Chem. Commun., 1993, 773.
21 K. N. Raymond, G. E. Freeman and M. J. Kappel, Inorg. Chim.
Acta, 1984, 94, 193; G. E. Freeman and K. N. Raymond, Inorg.
Chem., 1985, 24, 1410.
22 G. B. Deacon, T. Feng, S. Nickel, M. I. Ogden and A. H. White,
Aust. J. Chem., 1992, 45, 671.
23 W. J. Evans, R. E. Golden and J. W. Ziller, Inorg. Chem., 1993, 32,
3041.
24 H. Bock, K. Ruppert and D. Fenske, Angew. Chem., Int. Ed. Engl.,
1989, 28, 1685.
25 H. Bock, K. Ruppert, Z. Havlas and D. Fenske, Angew. Chem., Int.
Ed. Engl., 1990, 29, 1042.
26 Tables of Interatomic Distances and Configurations in Molecules and
Ions, ed. L. E. Sutton, The Chemical Society, London, 1958, p. S 17.
27 K. Nakatsu, H. Yoshioka, K. Kunimoto, T. Kinugasa and S. Ueji,
Acta Crystallogr., Sect. B, 1978, 34, 2357.
3 W. A. Herrmann, R. Anwander and M. Denk, Chem. Ber., 1993,
126, 1533 and refs. therein; D. C. Bradley, H. Chudzynska,
M. B. Hursthouse and M. Motevalli, Polyhedron, 1994, 13, 7 and
refs. therein.
4 G. B. Deacon and Q. Shen, J. Organomet. Chem., 1996, 511, 1.
5 (a) D. M. Barnhart, D. L. Clark, J. C. Gordon, J. C. Huffman,
R. L. Vincent, J. G. Watkin and B. D. Zwick, Inorg. Chem., 1994, 33,
3487; (b) R. J. Butcher, D. L. Clark, S. K. Grumbine, R. L. Vincent-
Hollis, B. L. Scott and J. G. Watkin, Inorg. Chem., 1995, 34, 5468.
6 G. B. Deacon, P. B. Hitchcock, S. A. Holmes, M. F. Lappert,
P. MacKinnon and R. H. Newnham, J. Chem. Soc., Chem.
Commun., 1989, 935; G. B. Deacon, T. Feng, P. MacKinnon,
R. H. Newnham, S. Nickel, B. W. Skelton and A. H. White, Aust.
J. Chem., 1993, 46, 387; J. R. van den Hende, P. B. Hitchcock,
S. A. Holmes and M. F. Lappert, J. Chem. Soc., Dalton Trans., 1995,
1435; J. R. van den Hende, P. B. Hitchcock and M. F. Lappert,
J. Chem. Soc., Chem. Commun., 1994, 1413; J. R. van den
Hende, P. B. Hitchcock, S. A. Holmes, M. F. Lappert, W.-P. Leung,
T. C. W. Mak and S. Prashar, J. Chem. Soc., Dalton Trans., 1995,
1427.
7 (a) D. L. Clark, J. G. Watkin and J. C. Huffman, Inorg. Chem., 1992,
31, 1554; (b) D. L. Clark, J. C. Gordon, J. C. Huffman, R. Vincent-
Hollis, J. G. Watkin and B. D. Zwick, Inorg. Chem., 1994, 33, 5903;
(c) D. L. Clark, R. V. Hollis, B. L. Scott and J. G. Watkin, Inorg.
Chem., 1996, 35, 667; (d) D. L. Clark, G. B. Deacon, T. Feng,
R. V. Hollis, B. L. Scott, B. W. Skelton, J. G. Watkin and
A. H. White, Chem. Commun., 1996, 1729.
28 S. R. Hall, H. D. Flack and J. M. Stewart (Editors), The XTAL 3.2
Reference Manual, Universities of Western Australia, Geneva and
Maryland, 1992.
Received 28th November 1996; Paper 6/08062F
1186
J. Chem. Soc., Dalton Trans., 1997, Pages 1181–1186