Group 1 bis(iminophosphorano)methanides, part 1: N -alkyl and silyl derivatives of the sterically demanding methanes H2C(PPh 2NR)2 (R = adamantyl and trimethylsilyl)

Article abstract of DOI:10.1021/om200553s

Treatment of [Li{HC(PPh₂NSiMe₃)₂}] ₂ with 2 equiv of [MOR] (M = Rb, Cs; OR = 2-ethylhexoxide) afforded the heavy group 1 methanides [Rb{HC(PPh₂NSiMe₃) ₂}(THF)₂] (1) and [Cs{HC(PPh₂NSiMe ₃)₂}(DME)₂] (2), which do not exhibit methanide C???M contacts in the solid state. Following a literature procedure, H₂C(PPh₂)₂ was reacted with 2 equiv of AdN₃ (Ad = adamantyl) to give H₂C(PPh ₂NAd)₂ (3). Reaction of 3 with 1 equiv of Bu^tLi in toluene afforded dimeric [Li{HC(PPh₂NAd)₂}] ₂ (4). Treatment of 3 with 1 equiv of [M(Bn)] (M = Na, K; Bn = CH₂C₆H₅) in THF gave the Lewis base adducts [M{HC(PPh₂NAd)₂}(THF)₂] [M = Na (5), K (6)]. The heavy group 1 methanides [Rb{HC(PPh₂NAd)₂}(THF) ₂] (7) and [Cs{HC(PPh₂NAd)₂}(DME)₂] (8) were prepared by the reaction of [MOR] (M = Rb, Cs; OR = 2-ethylhexoxide) with 4 or reaction of [Cs(Bn)] with 3. The synthetic utility of these group 1 transfer agents has been demonstrated by the preparation of [La{HC(PPh ₂NR)₂}(I)₂(THF)] [R = SiMe₃ (9), Ad (10)] from [La(I)₃(THF)₄], employing a salt metathesis methodology. Complexes 1-10 have been characterized by X-ray crystallography, multielement NMR spectroscopy, FTIR spectroscopy, and CHN microanalyses.

Full text of DOI:10.1021/om200553s

ARTICLE
pubs.acs.org/Organometallics
Group 1 Bis(iminophosphorano)methanides, Part 1: N-Alkyl and Silyl
Derivatives of the Sterically Demanding Methanes H2C(PPh2NR)2
(R = Adamantyl and Trimethylsilyl)
Ashley J. Wooles, Matthew Gregson, Oliver J. Cooper, Amy Middleton-Gear, David P. Mills, William Lewis,
Alexander J. Blake, and Stephen T. Liddle*
School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, U.K.
S Supporting Information
b
ABSTRACT: Treatment of [Li{HC(PPh2NSiMe3)2}]2 with 2 equiv of [MOR]
(M = Rb, Cs; OR = 2-ethylhexoxide) afforded the heavy group 1 methanides
[Rb{HC(PPh2NSiMe3)2}(THF)2] (1) and [Cs{HC(PPh2NSiMe3)2}(DME)2]
(2), which do not exhibit methanide C M contacts in the solid state. Following
3 3 3
a literature procedure, H2C(PPh2)2 was reacted with 2 equiv of AdN3 (Ad =
adamantyl) to give H2C(PPh2NAd)2 (3). Reaction of 3 with 1 equiv of ButLi in
toluene afforded dimeric [Li{HC(PPh2NAd)2}]2 (4). Treatment of 3 with 1 equiv
of [M(Bn)] (M = Na, K; Bn = CH2C6H5) in THF gave the Lewis base adducts
[M{HC(PPh2NAd)2}(THF)2] [M = Na (5), K (6)]. The heavy group 1 methanides
[Rb{HC(PPh2NAd)2}(THF)2] (7) and [Cs{HC(PPh2NAd)2}(DME)2] (8) were
prepared by the reaction of [MOR] (M = Rb, Cs; OR = 2-ethylhexoxide) with 4 or
reaction of [Cs(Bn)] with 3. The synthetic utility of these group 1 transfer agents has
been demonstrated by the preparation of [La{HC(PPh2NR)2}(I)2(THF)] [R =
SiMe3 (9), Ad (10)] from [La(I)3(THF)4], employing a salt metathesis methodology. Complexes 1ꢀ10 have been characterized by
X-ray crystallography, multielement NMR spectroscopy, FTIR spectroscopy, and CHN microanalyses.
’ INTRODUCTION
potassium complex is bound to the methanide ligand through the
two imino groups and an η2-arene contact only. The methane-
diide derivatives [{MM0(C[PPh2NR]2)}2] (M = M0 = Li, Na, K,
Rb; R = SiMe3, (S)-MeCHPri, Ph)7,10ꢀ14 are less structurally
diverse and typically adopt structures where a belt of four alkali
metals is capped top and bottom by mutually orthogonal
methanediide ligands. The corresponding [{Li2(C[PPh2S]2)}2-
(OEt2)n] (n = 2, 3)15 and [{Li2(C[PPh2NSiMe3][PPh2S]2)}2-
(THF)]9 complexes adopt similar structures, but the re-
placement of one or more of the imino substituents with less
sterically demanding thionyl groups results in the coordina-
tion of ethers.
In our early investigations into the chemistry of early metal
methanide and methanediide complexes, we typically accessed the
desired products, such as [Y{C(PPh2NSiMe3)2}(CH2SiMe3)-
(THF)], by the straightforward reaction between the parent
bis(iminophosphorano)methane and homo- and heteroleptic
lanthanide alkyls.16ꢀ20 However, this synthetic methodology
has its limitations; for example, larger rare-earth tribenzyls form
complexes, such as [Ln{C(PPh2NSiMe3)2}{HC(PPh2NSiMe3)2}],
and larger rare-earth [Ln(Bn)2(I)(THF)3] precursor complexes
are apparently unstable.19 In addition, we were interested in the
preparation of uranium methanide and methanediide complexes,
Bis(iminophosphorano)methanides and methanediides1 have
received increasing attention over the last 12 years, as they are
excellent ancillary ligands for a wide range of metal centers.1
Although direct reaction of the parent methanes with metal alkyls
and amides is often used to access the corresponding methanide
and methanediide complexes, alkali metal methanide and metha-
nediide complexes have found great utility as ligand transfer
reagents for the stepwise construction of derivatives by salt
elimination reactions. In addition to their extensive synthetic
utility, alkali metal methanide and methanediide complexes are
of interest because of their diverse structural chemistry. For
example, the solvent-free complexes [M{HC(PPh2NSiMe3)2}]2
(M = Li, Na, K)2,3 exist as methanide- (for lithium) and
N-bridged dimers (for sodium and potassium) in the solid state.
When N-aryl substituents are employed, multihapto interactions
are observed for potassium, as exemplified by [{K(HC[PPh2-
NMes]2)}2] (Mes = 2,4,6-trimethylphenyl),4 which was found to
be an η6-arene-bridged dimer in the solid state. However, the addition
of Lewis base solvents gives rise to structural modifications. For
example, the ether adducts [Li{HC(PR02NR)2}(L)] (R=SiMe3, Pri,
Mes; R0 = Ph, Cy; L = OEt2, THF),3,5ꢀ8 [Li{HC(PPh2NSi-
Me3)(PPh2S)}(THF)2],9 [Na{HC(PPh2NSiMe3)2}(THF)2],5
[K{HC(PPh2NSiMe3)2}(diglyme)],3 and [K{HC(PPh2NSi-
Me3)2}(THF)2]5 all adopt monomeric structures in the solid
state, but metalꢀmethanide contacts are often absent. The latter
Received: June 27, 2011
Published: September 26, 2011
r
2011 American Chemical Society
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Scheme 1. Synthesis of 1 and 2
and stable homoleptic neutral uranium(IV) alkyl precursors
remain elusive.21 As a consequence, we have recently exploited
previously reported group 1 methanides and methanediides as
ligand transfer agents using a salt metathesis methodology.22ꢀ25
Gratifyingly, these studies have allowed the synthesis of an early
rare-earth iodo-methanediide complex,23 a comparison of the
bonding and reactivity of U(IV) and U(V) carbenes,24 and the
preparation of a delocalized arene-bridged diuranium single-
molecule magnet.25 Furthering this study, we have also prepared
novel group 1 methanide and methanediide complexes.26,27 We
demonstrated the synthetic utility of the dilithium methanediide
complex [{Li2(C[PPh2NMes]2)}2] by preparing the first homo-
leptic uranium carbene complex to exhibit two UdC double
bonds.26 We have also recently reported the monomeric metha-
nide and methanediide complexes [Li{HC(PPh2NDipp)2}] and
[Li{C(PPh2NDipp)2}Li(TMEDA)] (TMEDA = N, N0-tetra-
methylethylenediamine),27 which exhibit a two-coordinate lithium
with no methanide contact in the former and a remarkable
distorted trans-planar tetracoordinate carbon in the latter.
We have found, however, that, in some cases, an apparently
straightforward salt metathesis methodology to prepare lantha-
nide methanide complexes from known group 1 methanide
precursors has, in fact, proven problematic.28 For example,
treatment of [La(I)3(THF)4] with [K{HC(PPh2NSiMe3)2}-
(THF)2] did not afford the desired monosubstituted lanthanide
methanide.23 We reasoned that this sluggish reactivity could
be overcome by starting with cesium and rubidium methanide
precursors, as the larger, more electropositive and polarizable
Rb+ and Cs+ ions (effective ionic radii, coordination number 6:
K+ 1.38 Å; Rb+ 1.52 Å; Cs+ 1.67 Å)29 should be more labile and
hence their methanide complexes should exhibit greater reactiv-
ity. We have expanded this study by obtaining the solid-state
structure of the corresponding N-Ad substituted bis(imino-
phosphorano)methane and its lithium, sodium, potassium, rubi-
dium, and cesium methanide derivatives. The synthetic utility of
these novel ligand transfer reagents has been proved by their use
in the facile preparation of lanthanum methanide complexes.
This provides an entry point to N-alkyl bis(iminophosphorano)-
methanide and -diide complexes by salt elimination, which
provides a valuable alternative to amine and alkyl elimination
methods.
Figure 1. Molecular structure of 1 with selective atom labeling.
Displacement ellipsoids are set at 40%, and hydrogen atoms are omitted
for clarity.
has previously been prepared by Harder and its NMR spectro-
scopic data reported, though it was not isolated.14 The reaction
to form 1 and 2 proceeds under mild conditions according to the
HSAB principle, driven by the affinity of hard electropositive
lithium to the alkoxide and the softer, more polarizable rubidium
and cesium centers to the methanide ligand.31 Henderson12,13
and Harder14 have previously employed group 1 alkoxides to
substitute the lithium cations of [Li2{C(PPh2NSiMe3)2}]2 with
heavier group 1 metals to prepare bimetallic methanediide
complexes, and this method has been successfully adapted to
prepare heavy group 1 methanides. This synthetic methodology
was found to tolerate a variety of solvent systems, and the lithium
alkoxide is easily separated from the products by extraction with
hexanes, leaving the products behind, which are only sparingly
soluble in this solvent. This procedure gives analytically and
spectroscopically pure 1 and 2 in good (ca. 75%) yields as
white powders. 7Li NMR spectroscopy indicated that no lithium-
containing species remained in the reaction mixtures, and only a
single resonance was observed in the 31P{1H} NMR spectra of
each reaction mixture [δ 11.87 (1); 10.73 (2) ppm], which are
comparable to that observed for [Rb{HC(PPh2NPh)2}(THF)x]
(δ 10.94 ppm).14 Complexes 1 and 2 each exhibit a virtual trip-
let resonance in their 29Si{1H} NMR spectra [δ, ꢀ17.08 ppm,
2JSiP = 6.4 Hz (1); ꢀ17.19 ppm, 2JSiP = 6.7 Hz (2)] from coupling
to magnetically inequivalent phosphorus centers, a phenomenon
we have previously observed in several other complexes of
{HC(PPh2NSiMe3)2}ꢀ and {C(PPh2NSiMe3)2}2ꢀ 17,18,20,22 The
.
expected triplet methanide resonances of 1 and 2 were observed in
both their 1H [1.92 ppm, 2JPH = 2.6 Hz (1); 1.84 ppm, 2JPH = 2.2
Hz (2)] and their 13C{1H} [23.39 ppm, JPC = 134.8 Hz (1); 23.44
ppm, JPC = 145.9 Hz (2)] NMR spectra and again are comparable
to resonances displayed by [Rb{HC(PPh2NPh)2}(THF)x] (1H δ
1.78 ppm, 2JPH = 3.2 Hz; 13C{1H} δ 15.3 ppm, coupling constant
not reported).14
To confirm the formulations of 1 and 2, crystals were grown
from saturated THF and DME solutions, respectively, to allow
single-crystal X-ray determination of their solid-state structures
(Figures 1 and 2; selected bond lengths and angles are listed
in Table 1). The bis(iminophosphorano)methanide ligands of
’ RESULTS AND DISCUSSION
The reaction of half an equivalent of [Li{HC-
2,3
(PPh2NSiMe3)2}]2 with [MOR] (M = Rb, Cs; R = 2-ethyl-
hexoxide)30 in the presence of the appropriate Lewis base gave
the desired heavy group 1 methanides [Rb{HC(PPh2N-
SiMe3)2}(THF)2] (1) and [Cs{HC(PPh2NSiMe3)2}(DME)2]
(2), by simple metal exchange (Scheme 1). It is noteworthy that
the closely related compound [Rb{HC(PPh2NPh)2}(THF)x]
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as they formally consist of the donation of electron density from
the CꢀH bond to the metal cation as well as an electrostatic
component deriving from the interaction of dipoles. The dona-
tion of electron density from methyl groups is maximized by a
linear approach of the methyl group to the metal center, allowing
all three M H interactions.33,34 In the case of 1, there is sig-
3 3 3
nificant rotational disorder of the N-silyl substituents, but the major
component displays a “side-on”coordination of two methyl groups to
rubidium, allowing four Rb H contacts [3.065(2)ꢀ3.338(2) Å].
3 3 3
The resultant Rb C distances [3.397(2)ꢀ3.632(2) Å] are
3 3 3
similar to those observed in [Rb(C7H8)3][M{N(SiMe3)2}3]
[M = Mg, Zn; Rb C 3.544(4)ꢀ3.626(3) Å].34 Complex 2
3 3 3
displays two short [3.032(4)ꢀ3.111(4) Å] and two long
[3.497(4)ꢀ3.670(4) Å] Cs H interactions from one methyl
3 3 3
group of each silyl functionality, resulting in two short Cs
C
H
3 3 3
3 3 3
distances [3.587(4)ꢀ3.696(4) Å]. An additional two Cs
contacts between two methylene fragments of DME and
the metal center [3.394(4)ꢀ3.417(4) Å] are exhibited by 2.
The P(1)ꢀC(1)ꢀP(2) [121.11(11)° (1); 122.7(2)° (2)] and
N(1)ꢀMꢀN(2) [81.75(5)° (1); 77.58(10)° (2)] angles are
extremely small considering the size of the group 1 metals and
steric bulk of the methanide ligand [cf. PꢀCꢀP 144.4(1)° and
NꢀRbꢀN 119.2(1)° for [{Rb2C(PPh2NPh)2}2(C6H6)4]]14
and are a direct consequence of the unusual geometry adopted
by the ligand in these complexes.
Figure 2. Molecular structure of 2 with selective atom labeling.
Displacement ellipsoids are set at 40%, and hydrogen atoms are omitted
for clarity.
both 1 and 2 exhibit an atypical conformation upon coordination
to the group 1 metal through the nitrogen lone pairs.The bulk
features are similar, so only the geometry of 1 is discussed in
detail for brevity. 1 displays nearly perfectly defined P(1)ꢀC-
(1)ꢀP(2)ꢀM(1) and N(1)ꢀC(1)ꢀN(2)ꢀM(1) planes (mean
plane deviation of 0.0026 and 0.0174 Å, respectively) that bisect
at an angle of 29.77(5)°. The coordination spheres of both 1 and
2 are completed by two molecules of solvent, the larger cesium
center by bidentate DME. The mean MꢀN distances [RbꢀN
2.8812 Å (1); CsꢀN 3.185 Å (2)] lie within previously reported
ranges (RbꢀN 2.796ꢀ3.609 Å; CsꢀN 2.915ꢀ3.678 Å)32 and, in
the case of 1, are shorter than in the related methanediide
complex [{Rb2C(PPh2NPh)2}2(C6H6)4] [RbꢀN 2.923(3) Å
mean].14 The mean endocyclic PꢀC distances [1.714 Å (1);
1.726 Å (2)] and PꢀN distances [1.5733 Å (1); 1.572 Å (2)] are
relatively long and short, respectively, when compared to
[{Rb2C(PPh2NPh)2}2(C6H6)4] [PꢀC 1.648(2) Å; PꢀN
1.626(3) Å mean]. Both 1 and 2 do not exhibit a methani-
deꢀmetal contact [Rb(1) C(1) 4.276(2) Å (1); Cs(1)
Treatment of CH2(PPh2)2 with 2 equiv of AdN3 according to
the previously described method of Cavell afforded the methane
H2C(PPh2NAd)2 (3) (Scheme 2).36 Compound 3 was pre-
viously only characterized spectroscopically and analytically.
During a routine purification procedure, we obtained colorless
crystals of 3 and determined the structure by X-ray crystal-
lography. The molecular structure of 3 is illustrated in Figure 3,
and selected bond lengths and angles are listed in Table 1. 3
exhibits average endocyclic PꢀC and PꢀN bond distances of
1.8534 and 1.5465 Å, respectively, which are slightly longer than,
but comparable to, the corresponding distances of 1.825(1) and
1.536(2) Å found in the solid-state structure of H2C(PPh2-
SiMe3)2,37 as would be anticipated. The P(1)ꢀC(1)ꢀP(2)
angle in 3 of 121.38(10)° is smaller than that displayed by
H2C(PPh2SiMe3)2 [124.94(15)°],37 but this is a consequence of
the bulky N-adamantyl groups favoring a trans conformation of
the N-substituents, rather than the cis conformation exhibited by
H2C(PPh2SiMe3)2.37
3 3 3
3 3 3
C(1) 4.543(4) Å (2)], but each displays an electrostatic interaction
of the metal with one of the P-phenyl rings, formally η2- in the case
of 1 [Rb(1) C(8) 3.639(2) Å; Rb(1) C(13) 3.551(2) Å]
Compound 3 was treated with 1 equiv of ButLi in toluene to
afford the expected dimeric product [Li{HC(PPh2NAd)2}]2 (4)
(Scheme 2). The corresponding sodium and potassium metha-
nides were prepared by the reaction of 3 with [M(Bn)] (M =
Na,38 K39) in THF to give the respective Lewis base adducts [M-
{HC(PPh2NAd)2}(THF)2] [M = Na (5), K (6)] (Scheme 2).
Compounds 4ꢀ6 all exhibited a single resonance in their
31P{1H} NMR spectra at δ 10.53, 9.45, and 4.90 ppm, respec-
tively. These resonances are all upfield of those observed in the
related complexes [Li{HC(PPh2NSiMe3)2}]2 (δ 17.4 ppm),2
[Na{HC(PPh2NSiMe3)2}(THF)2] (δ 15.2 ppm),5 and [K{HC-
(PPh2NSiMe3)2}(THF)2] (δ 12.6 ppm).5 The methanide pro-
ton resonance of 4 was not observed in its 1H NMR spectrum as
it was obscured by methylene signals of the N-adamantyl groups.
This resonance was observed in the 1H NMR spectra of 5 and 6,
however, as a broad singlet in the spectrum of 5 (δ 1.61 ppm) and
as a triplet in the spectrum of 6 (δ 1.64 ppm, 2JPH = 3.40 Hz)
from coupling to two equivalent 31P nuclei. These findings are in
agreement with the 1H NMR spectral data reported by Cavell for
3 3 3
3 3 3
and η1- for 2 [Cs(1) C(13) 3.763(4) Å]. An η2-interaction of
3 3 3
rubidium with a P-phenyl ring was also observed in [{Rb2C-
(PPh2NPh)2}2(C6H6)4] [Rb C 3.520(3)ꢀ3.608(3) Å],14
3 3 3
which exhibits similar Rb C distances, but this complex possesses
3 3 3
two short methanideꢀrubidium contacts [RbꢀC 3.047(3) Å],
which are likely a result of the metal centers not being
coordinated by Lewis base solvent molecules as they are in 1
and 2. The intramolecular η1-P-phenyl contact found in 2 is
more accurately described as coordination of a CꢀH bond to
cesium, a phenomenon previously observed in [{CsSi(SiMe3)3}2-
(biphenylene)] [Cs C 3.683(7) Å],33 although, unlike 2, this
3 3 3
contact is intermolecular and the Cs C distance is much
3 3 3
shorter. Agostic interactions between methyl groups of the
N-silyl substituents and the group 1 metal centers are observed
for both 1 and 2. These s-block agostic interactions33,34 have
been shown to differ from transition-metal agostic interactions35
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Table 1. Selected Bond Lengths (Å) and Angles (°) for 1ꢀ10
1
6
C(1)ꢀP(1)
P(1)ꢀN(1)
K(1)ꢀN(1)
K(1)ꢀO(1)
1.7163(15) C(1)ꢀP(2)
1.5848(13) P(2)ꢀN(2)
2.7970(13) K(1)ꢀN(2)
2.6840(12) K(1)ꢀO(2)
1.7245(15)
1.5802(12)
2.8524(13)
2.8804(13)
3.264(15)
3.209(15)
C(1)ꢀP(1)
P(1)ꢀN(1)
Rb(1)ꢀN(1)
Rb(1)ꢀO(1)
1.715(2)
C(1)ꢀP(2)
1.713(2)
1.5732(17)
2.9061(17)
2.845(2)
3.639(2)
3.632(2)
1.5733(17) P(2)ꢀN(2)
2.8562(17) Rb(1)ꢀN(2)
2.807(2)
4.276(2)
3.551(2)
3.397(2)
Rb(1)ꢀO(2)
K(1) C(1)
4.082(2)
K(1) C(2)
3 3 3
3 3 3
Rb(1) C(1)
Rb(1) C(8)
3 3 3
3 3 3
K(1) C(7)
3.297(15) K(1) C(17)
3 3 3
3 3 3
Rb(1) C(13)
Rb(1) C(15)
3 3 3
3 3 3
K(1) C(39)
3.130(15)
3 3 3
Rb(1) C(30A)
3 3 3
P(1)ꢀC(1)ꢀP(2)
128.28(9)
N(1)ꢀK(1)ꢀN(2)
88.27(4)
N(1)ꢀRb(1)ꢀN(2) 81.75(5)
P(1)ꢀN(1)ꢀRb(1) 108.95(9)
N(1)ꢀP(1)ꢀC(1) 119.34(10)
P(1)ꢀC(1)ꢀP(2)
P(2)ꢀN(2)ꢀRb(1) 112.94(8)
N(2)ꢀP(2)ꢀC(1) 116.95(10)
121.11(11)
N(1)ꢀP(1)ꢀC(1) 125.83(7)
P(1)ꢀN(1)ꢀK(1) 100.40(6)
N(2)ꢀP(2)ꢀC(1) 112.96(7)
P(2)ꢀN(2)ꢀK(1) 120.32(6)
7 0.5C7H8
3
C(1)ꢀP(1)
P(1)ꢀN(1)
Rb(1)ꢀN(1)
Rb(1)ꢀO(1)
1.7263(17) C(1)ꢀP(2)
1.7283(16)
1.5750(14)
2.9337(14)
2.8801(14)
3.5087(16)
3.405(2)
2
1.5837(14) P(2)ꢀN(2)
2.9641(13) Rb(1)ꢀN(2)
2.9278(14) Rb(1)ꢀO(2)
C(1)ꢀP(1)
P(1)ꢀN(1)
Cs(1)ꢀN(1)
Cs(1)ꢀO(1)
Cs(1)ꢀO(3)
1.717(4)
1.568(4)
3.160(4)
3.147(4)
3.203(4)
4.543(4)
3.696(4)
C(1)ꢀP(2)
P(2)ꢀN(2)
Cs(1)ꢀN(2)
Cs(1)ꢀO(2)
Cs(1)ꢀO(4)
1.734(4)
1.575(4)
3.210(4)
3.257(4)
3.131(4)
3.763(4)
3.587(4)
Rb(1) C(1)
4.163(2)
Rb(1) C(8)
3 3 3
3 3 3
Rb(1) C(9)
3.4745(18) Rb(1) C(17)
3 3 3
3 3 3
Rb(1) C(37)
3.419(2)
3 3 3
Cs(1) C(1)
Cs(1) C(13)
3 3 3
3 3 3
N(1)ꢀRb(1)ꢀN(2) 87.76(4)
P(1)ꢀN(1)ꢀRb(1) 100.81(6)
N(1)ꢀP(1)ꢀC(1) 126.73(8)
P(1)ꢀC(1)ꢀP(2)
P(2)ꢀN(2)ꢀRb(1) 111.30(6)
N(2)ꢀP(2)ꢀC(1) 116.83(8)
125.50(10)
Cs(1) C(26)
Cs(1) C(29)
3 3 3
3 3 3
N(1)ꢀCs(1)ꢀN(2) 77.58(10)
P(1)ꢀN(1)ꢀCs(1) 110.56(18)
N(1)ꢀP(1)ꢀC(1) 120.2(2)
P(1)ꢀC(1)ꢀP(2)
P(2)ꢀN(2)ꢀCs(1) 110.37(18)
N(2)ꢀP(2)ꢀC(1) 122.1(2)
122.7(2)
8 0.5C4H10O2
3
C(1)ꢀP(1)
P(1)ꢀN(1)
Cs(1)ꢀN(1)
Cs(1)ꢀO(1)
Cs(1)ꢀO(3)
1.718(4)
C(1)ꢀP(2)
P(2)ꢀN(2)
Cs(1)ꢀN(2)
Cs(1)ꢀO(2)
Cs(1)ꢀO(4)
1.725(4)
1.576(4)
3.160(4)
3.211(3)
3.162(3)
3.624(4)
3.697(4)
1.582(4)
3.161(4)
3.205(3)
3.172(3)
4.482(4)
3.542(4)
3.633(4)
3
C(1)ꢀP(1)
1.8468(19) C(1)ꢀP(2)
1.5490(17) P(2)ꢀN(2)
1.8600(19)
1.5440(17)
P(1)ꢀN(1)
P(1)ꢀC(1)ꢀP(2)
121.38(10)
C(1)ꢀP(1)ꢀN(1) 119.37(9)
Cs(1) C(1)
Cs(1) C(9)
3 3 3
3 3 3
C(1)ꢀP(2)ꢀN(2) 117.16(9)
Cs(1) C(16)
Cs(1) C(25)
3 3 3
3 3 3
4
Cs(1) C(39)
3 3 3
C(1)ꢀP(1)
C(46)ꢀP(3)
P(1)ꢀN(1)
P(3)ꢀN(3)
Li(1)ꢀN(1)
Li(2)ꢀN(2)
1.743(4)
1.737(4)
1.595(3)
1.597(3)
1.986(8)
1.998(8)
2.673(8)
2.320(8)
C(1)ꢀP(2)
C(46)ꢀP(4)
P(2)ꢀN(2)
P(4)ꢀN(4)
Li(1)ꢀN(4)
Li(2)ꢀN(3)
1.729(4)
1.731(4)
1.593(4)
1.601(4)
2.009(8)
1.981(8)
2.339(8)
2.685(8)
N(1)ꢀCs(1)ꢀN(2) 80.15(10)
P(1)ꢀN(1)ꢀCs(1) 108.31(18)
N(1)ꢀP(1)ꢀC(1) 124.3(2)
P(1)ꢀC(1)ꢀP(2)
P(2)ꢀN(2)ꢀCs(1) 111.02(18)
N(2)ꢀP(2)ꢀC(1) 121.4(2)
124.2(2)
9 0.5C7H8
3
C(1)ꢀP(1)
P(1)ꢀN(1)
La(1)ꢀN(1)
La(1)ꢀO(1)
La(1)ꢀI(1)
P(1)ꢀC(1)ꢀP(2)
N(1)ꢀP(1)ꢀC(1) 109.2(4)
P(1)ꢀN(1)ꢀLa(1) 103.6(3)
1.728(8)
C(1)ꢀP(2)
P(2)ꢀN(2)
La(1)ꢀN(2)
La(1)ꢀC(1)
1.739(8)
1.611(7)
2.412(6)
2.859(8)
3.1981(6)
1.609(7)
2.463(6)
2.624(6)
Li(1) C(1)
Li(1) C(46)
3 3 3
3 3 3
Li(2) C(1)
Li(2) C(46)
3 3 3
3 3 3
3.1800(6) La(1)ꢀI(2)
135.9(5)
P(1)ꢀC(1)ꢀP(2)
P(1)ꢀN(1)ꢀLi(1) 110.2(3)
P(3)ꢀN(3)ꢀLi(2) 110.2(3)
136.5(2)
P(3)ꢀC(46)ꢀP(4) 134.0(3)
P(2)ꢀN(2)ꢀLi(2)
P(4)ꢀN(4)ꢀLi(1)
N(1)ꢀLa(1)ꢀN(2) 111.9(2)
N(2)ꢀP(2)ꢀC(1) 107.9(4)
P(2)ꢀN(2)ꢀLa(1) 104.3(3)
95.4(3)
94.9(3)
5
10 1.5C4H8O
3
C(1)ꢀP(1)
P(1)ꢀN(1)
Na(1)ꢀN(1)
Na(1)ꢀO(1)
1.7233(13) C(1)ꢀP(2)
1.5819(12) P(2)ꢀN(2)
2.4460(12) Na(1)ꢀN(2)
2.3924(12) Na(1)ꢀO(2)
1.7252(13)
1.5931(11)
2.4528(12)
2.3495(12)
3.396(2)
C(1)ꢀP(1)
P(1)ꢀN(1)
La(1)ꢀN(1)
La(1)ꢀO(1)
La(1)ꢀI(1)
1.734(4)
C(1)ꢀP(2)
P(2)ꢀN(2)
La(1)ꢀN(2)
La(1)ꢀC(1)
1.731(4)
1.614(4)
2.410(3)
2.826(4)
3.2167(4)
3.253(4)
1.613(4)
2.413(3)
2.620(3)
Na(1) C(1)
3.701(2)
Na(1) C(25)
3 3 3
3 3 3
3.1928(4) La(1)ꢀI(2)
3.139(4) La(1) C(37)
Na(1) C(26)
3.431(2)
La(1) C(15)
3 3 3
3 3 3
3 3 3
137.1(2)
P(1)ꢀC(1)ꢀP(2)
N(1)ꢀP(1)ꢀC(1) 117.17(6)
P(1)ꢀN(1)ꢀNa(1) 115.38(6)
128.69(8)
N(1)ꢀNa(1)ꢀN(2) 102.68(4)
N(2)ꢀP(2)ꢀC(1) 123.09(6)
P(2)ꢀN(2)ꢀNa(1) 101.98(5)
P(1)ꢀC(1)ꢀP(2)
N(1)ꢀLa(1)ꢀN(2) 114.73(12)
N(2)ꢀP(2)ꢀC(1) 105.54(19)
P(2)ꢀN(2)ꢀLa(1) 106.06(16)
N(1)ꢀP(1)ꢀC(1) 104.5(2)
P(1)ꢀN(1)ꢀLa(1) 105.26(17)
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Scheme 2. Synthesis of 3ꢀ8
Figure 4. Molecular structure of 4 with selective atom labeling.
Displacement ellipsoids are set at 40%, and hydrogen atoms are omitted
for clarity.
Figure 3. Molecular structure of 3 with selective atom labeling.
Displacement ellipsoids are set at 30%, and hydrogen atoms are omitted
for clarity.
[Na{HC(PPh2NSiMe3)2}(THF)2] (δ 1.95 ppm, br s) and
[K{HC(PPh2NSiMe3)2}(THF)2] (δ 1.82 ppm, t, JPH = 2.8
Figure 5. Molecular structure of 5 with selective atom labeling.
Displacement ellipsoids are set at 40%, and hydrogen atoms are omitted
for clarity.
2
Hz).5 Although the corresponding methanide resonance was not
observed in the 13C{1H} NMR spectra of 4 or 5, the 13C{1H}
NMR spectrum of 6 exhibited the expected triplet at δ 26.95
ppm (JPC = 141.86 Hz), which is similar to that observed for
[K{HC(PPh2NSiMe3)2}(THF)2] (δ 24.1 ppm, JPC = 134.0
Hz).5 Additionally, 4 displayed a single resonance in its 7Li{1H}
NMR spectrum at δ 2.32 ppm, which compares to the related
complex [Li{HC(PPh2NSiMe3)2}]2 (δ 0.70 ppm).2
four-membered rings are fused to the core metallacycle, two of
which project above and two project below the Li(1)ꢀC(1)ꢀ
Li(2)ꢀC(46) plane. The lithiumatomsof 4eachdisplay one short
and one long CꢀLi distance [2.330(8) and 2.679(8) Å mean],
complementary to [Li{HC(PPh2NSiMe3)2}]2, which exhibits
significantly different CꢀLi distances [2.370(9)ꢀ2.784(10) Å].2
Also in common with [Li{HC(PPh2NSiMe3)2}]2, the methine
hydrogen atoms of 4 are in relatively close proximity to the
lithium atoms [Li(1) H(1) 2.221(8) Å and Li(2) H(3)
The solid-state structures of 4ꢀ6 were determined by single-
crystal X-ray diffraction. Their molecular structures are illustrated
in Figures 4ꢀ6, and selected bond lengths and angles are listed in
Table 1. In the solid state, 4 is dimeric and exhibits a similar
structure to that reported for [Li{HC(PPh2NSiMe3)2}]2,2 with
the methanide carbons bridged by two lithium centers to form a
distorted four-membered ring. Four nearly planar LiꢀNꢀPꢀC
3 3 3
3 3 3
2.301(8) Å, Li(1)ꢀC(1)ꢀH(1) 53.0(3)° and Li(1)ꢀC(1)ꢀ
H(1) 57.1(3)°], indicative of strong agostic interactions between
CꢀH and Li.33ꢀ35 In contrast to [Li{HC(PPh2NSiMe3)2}]2,
however, each lithium atom of 4 exhibits one strong agostic
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Figure 6. Molecular structure of 6 with selective atom labeling. Displace-
ment ellipsoids are set at 40%, and hydrogen atoms are omitted for clarity.
Figure 7. Molecular structure of 7 0.5C7H8 with selective atom label-
ing. Displacement ellipsoids are set at 40%, and hydrogen atoms and
lattice solvent are omitted for clarity.
3
interaction, whereas one of the lithium centers in the N-silyl
analogue exhibits two strong agostic interactions, explaining the
greater variation in LiꢀC distances in the previously reported
compound.2 Despite the considerable steric bulk of the N-sub-
stituents of 4, its mean endocyclic CꢀP [1.735 Å], PꢀN [1.597
Å], and NꢀLi [1.994 Å] bond lengths are statistically identical
to the mean distances exhibited by [Li{HC(PPh2NSiMe3)2}]2
[1.737, 1.588, and 2.012 Å, respectively], as are the metrical
parameters of the four-membered rings.2 The molecular struc-
tures of monomeric bis-THF-coordinated 5 and 6 both exhibit
six-membered rings formed by chelation of the two imino
nitrogen atoms to the alkali metal with the methanide carba-
for [K{CH(PPh2NSiMe3)2}(THF)2], in which the potassium
center also exhibits an η2-aryl contact with one of the P-phenyl
substituents [K C 3.416(3)ꢀ3.456(3) Å] as well as agostic
3 3 3
interactions with three CꢀH bonds of one silyl group (K
2.73ꢀ3.15 Å).5
H
3 3 3
Treatment of 4 with 2 equiv of [Rb(OR)] (OR = 2-
ethylhexoxide) in THF afforded [Rb{HC(PPh2NAd)2}(THF)2]
(7) in 52% crystalline yield following workup (Scheme 2). The
heavier cesium analogue could not be prepared by this method,
however, as [Cs(OR)]30 was found to not react with 4 under
these conditions. [Cs{HC(PPh2NAd)2}(DME)2] (8) was alter-
natively accessed by the treatment of 3 with [Cs(Bn)]14 in THF,
followed by treatment with DME (Scheme 2). The 31P{1H}
NMR spectra of 7 (δ 4.06 ppm) and 8 (δ ꢀ0.58 ppm) displayed
the expected singlet resonances upfield of 1ꢀ2 and 5ꢀ6 (vide
supra). The methine proton produces a triplet resonance in the
1H NMR spectrum of 7 (δ 1.59 ppm, 2JPH = 2.9 Hz) but is only
observed as a broad singlet for 8 (δ 2.15 ppm), although the
chemical shifts are comparable with those observed for 1 and 2.
Germane to this, the methanide carbons of 7 and 8 resonate at
similar chemical shifts to 1ꢀ2 and 6 and exhibit comparable
coupling constants [δ 25.58 ppm, JPC = 133.8 Hz (7); δ 23.99
ppm, JPC = 134.8 Hz (8)].
nion remaining uncoordinated [the C(1)
3.701(2) Å in 5 and 4.082(2) Å in 6] in an analogous fashion to
M(1) distance is
3 3 3
the methanide ligands in [Na{HC(PPh2NSiMe3)2}(THF)2]
[C Na 3.739(7) Å] and [K{HC(PPh2NSiMe3)2}(THF)2]
3 3 3
3 3 3
[C K 4.145(2) Å].5 Although the bond distances and geo-
metry of the bis(iminophosphorano)methanide scaffold of 5
[P(1)ꢀC(1)ꢀP(2) 128.69(8)°, N(1)ꢀNa(1)ꢀN(2) 102.68(4)°,
P(1)ꢀN(1)ꢀNa(1) 115.38(6)°, P(2)ꢀN(2)ꢀNa(1) 101.98(5)°,
N(1)ꢀP(1)ꢀC(1) 117.17(6)°, N(2)ꢀP(2)ꢀC(1) 123.09(6)°]
are comparable to those observed for [Na{CH(PPh2NSi-
Me3)2}(THF)2] [PꢀCꢀP 126.3(3)°, NꢀNaꢀN 96.8(2)°,
PꢀNꢀNa 111.4(2)°, NꢀPꢀC 116.4(2)°],5 it coordinates less
symmetrically and as such exhibits nonequivalent PꢀNꢀNa and
NꢀPꢀC bond angles. 6 displays an η2-aryl contact with one of
the P-phenyl substituents of the ligand framework and the metal
X-ray single-crystal diffraction experiments on 7 0.5C7H8 and
3
8 0.5C4H10O2 were performed, and their solid-state structures
3
were determined (Figures 7 and 8. Selected bond lengths and
angles are listed in Table 1). The bis(iminophosphorano)-
methanide frameworks of 7 and 8 coordinate to the group 1
metals to form six-membered chelate rings that are comparable in
their bulk geometry to 1 and 2 (vide supra), with essentially
planar P(1)ꢀC(1)ꢀP(2)ꢀM(1) and N(1)ꢀC(1)ꢀN(2)ꢀM(1)
units at an acute angle (<30°) with respect to each other. Despite
the greater steric bulk of the N-substituents of 7 and 8 in
comparison with 1 and 2, the mean endocyclic PꢀC and PꢀN
bond lengths of the ligand scaffold are analogous as are the
average MꢀN distances [MꢀN 2.9489 Å (7); 3.161 Å (8)],
center in the solid state [K C 3.264(15)ꢀ3.297(15) Å]. The
3 3 3
sodium center of 5 exhibits a Na H contact with a methylene
3 3 3
fragment of each of the N-adamantyl substituents [Na
H
3 3 3
2.421(2)ꢀ2.758(2) Å]. The larger potassium cation of 6 allows
more symmetrical agostic interactions, the corresponding
methylene fragments in this complex donating electron density
from both CꢀH bonds [K H 2.748(15)ꢀ2.943(15) Å], thus
3 3 3
allowing close approach of the methylene carbon atoms [K
C
3 3 3
3.130(15)ꢀ3.209(15) Å]. The η2-aryl and agostic interactions
observed in 6 are comparable to, but shorter than, those observed
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Scheme 3. Synthesis of 9 and 10
Figure 8. Molecular structure of 8 0.5C4H10O2 with selective atom
3
labeling. Displacement ellipsoids are set at 40%, and hydrogen atoms
and lattice solvent are omitted for clarity.
although the N(1)ꢀM(1)ꢀN(2) [87.76(4)° (7); 80.15(10)°
(8)] and P(1)ꢀC(1)ꢀP(2) [125.50(10)° (7); 124.2(2)° (8)]
angles are larger in 7 and 8 than in their N-silyl counterparts. The
coordination sphere of the metal centers of 7 and 8 are
completed by the same number and identity of donor solvent
molecules as 1 and 2, respectively. In common with 1 and 2, but
not with other related heavy s-block complexes, such as
[M{HC(PPh2NSiMe3)2}(I)(THF)n]2 (M = Sr, n = 1; M = Ba,
n = 2)40 and [M{HC(PPh2NSiMe3)2}2] (M = Sr,41 Ba42), no
methanideꢀmetal contacts were observed in the solid state
Figure 9. Molecular structure of 9 0.5C7H8 with selective atom label-
ing. Displacement ellipsoids are set at 40%, and hydrogen atoms and
lattice solvent are omitted for clarity.
3
[M(1) C(1) 4.163(2) Å (7); 4.482(4) Å (8)]. Like 1, 7
3 3 3
exhibits a π-base coordination of two carbon atoms of one of the
P-phenyl rings to rubidium [Rb C 3.509(2)ꢀ3.475(2) Å],
reacts with [La(I)3(THF)4] to yield 10, albeit in a poor (38%)
yield, similar to the preparation of [La{HC(PPh2NMes)2}-
(I)2(THF)3] from [K{HC(PPh2NMes)2}].23 Interestingly, uti-
lizing 7 or 8 instead of 6 makes very little difference to the
isolated yield of 10, which contrasts to the synthesis of 9. Both 9
and 10 display a single resonance in their 31P{1H} NMR spectra
at δ 17.63 and 12.11 ppm, respectively, the chemical shift for 9
being comparable to that for [La{CH(PPh2NSiMe3)2}-
3 3 3
but 8 differs to 2 in that it displays two η1-aryl contacts with P-
phenyl rings [Cs(1) C(9) 3.624(2) Å and Cs(1) C(25)
3 3 3
3 3 3
3.697(2) Å], whereas 2 only exhibited one of these contacts (vide
supra). Additionally, both 7 and 8 display four agostic inter-
actions between the group 1 metal and CꢀH bonds of the
N-adamantyl substituents, as was observed for 6, as adjudged by
close M H distances [2.829(2)ꢀ3.276(2) Å (7); 2.937(4)ꢀ
3 3 3
1
{N(SiHMe2)2}2] (δ 17.1 ppm)44 The H NMR spectra of 9
3.562(4) Å (8)] and acute MꢀCꢀH angles. As with 6, this
causes the methylene carbon atoms to be in close proximity to
the metal ions, the distances increasing with ionic radii as
and 10 both exhibit the expected resonance for the methine
proton, as a broad multiplet for 10 (δ 3.08 ppm), but as a well-
defined triplet for 9 (δ 3.17 ppm, 2JPH = 8.2 Hz), which is similar
to that observed for [La{CH(PPh2NSiMe3)2}{N(SiHMe2)2}2]
would be expected [M C 3.405(2)ꢀ3.419(2) Å (7); 3.542-
3 3 3
(4)ꢀ3.633(4) Å (8)].
2
To test our initial hypothesis, and the synthetic utility of these
novel group 1 ligand transfer agents, 1 and 6 were reacted with
[La(I)3(THF)4]43 in THF, and gratifyingly, the lanthanide
methanide complexes [La{HC(PPh2NSiMe3)2}(I)2(THF)] (9)
and [La{HC(PPh2NAd)2}(I)2(THF)] (10) were obtained fol-
lowing elimination of RbI and KI, respectively, and workup
(Scheme 3). The isolation of 9 is noteworthy because this
complex cannot be accessed from the reaction of [La(I)3-
(THF)4] with [K{HC(PPh2NSiMe3)2}(THF)2],23 but both 1
and 2 react with the same lanthanum triiodide precursor to afford
9 in good (77%) yield. It is important to note, however, that, for
the corresponding N-adamantyl system, the potassium salt 6
(δ 2.35 ppm, JPH = 6.3 Hz).44 The corresponding methanide
triplet resonances in the 13C{1H} NMR spectra of 9 (δ 12.86
ppm, JPC = 118.9 Hz) and 10 (δ 11.15 ppm, JPC = 139.5 Hz) are
both well-resolved and considerably upfield of the N-mesityl-
substituted analogue, [La{HC(PPh2NMes)2}(I)2(THF)3] (δ58.76
ppm, JPC = 148.4 Hz).23 Finally, the 29Si{1H} NMR spectrum of
9 displays a single resonance (δ ꢀ4.86 ppm) that is comparable
to that observed for [La{CH(PPh2NSiMe3)2}{N(Ph2P)2}(Cl)]
(δ ꢀ1.2 ppm).44
To confirm the formulation of 9 and 10, the structures were
determined by X-ray crystallography (Figures 9 and 10; se-
lected bond lengths and angles are listed in Table 1). The
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ARTICLE
parent methanes with the appropriate metal alkoxide or benzyl
precursor in the presence of coordinating solvents. The pre-
viously reported N-adamantyl bis(iminophosphorano)methane
H2C(PPh2NAd)2 (3) has been structurally characterized. Treat-
ment of 3 with alkali metal reagents afforded dimeric lithium
[Li{HC(PPh2NAd)2}]2 (4) and monomeric sodium [Na{HC-
(PPh2NAd)2}(THF)2] (5) and potassium [K{HC(PPh2NAd)2}-
(THF)2] (6) salts. The synthetic utility of 1 and 2 has been
demonstrated by their use in the preparation of [La{HC(PPh2-
NSiMe3)2}(I)2(THF)] (9) from [La(I)3(THF)4], overcoming a
previous synthetic barrier. The corresponding N-adamantyl
analogue [La{HC(PPh2NAd)2}(I)2(THF)] (10) was easily
prepared from the reaction of [La(I)3(THF)4] with lighter group
1 methanides, such as 6, proving the synthetic potential of the N-
alkyl variant. We envisage that complexes 1ꢀ2 and 4ꢀ8 repre-
sent novel alkali metal transfer reagents that will prove useful in
preparing other sterically constrained d- and f-block methanide
complexes in the future. At present, we are utilizing 1ꢀ2 and
4ꢀ8 in the preparation of f-block methanide systems, which are
proving to be suitable precursors for related methanediide
systems by a simple deprotonation methodology. The findings
of these studies will be published in due course.
Figure 10. Molecular structure of 10 1.5C4H8O with selective atom
3
labeling. Displacement ellipsoids are set at 40%, and hydrogen atoms
and lattice solvent are omitted for clarity.
’ EXPERIMENTAL SECTION
General. All manipulations were carried out using standard Schlenk
techniques, or an MBraun UniLab glovebox, under an atmosphere of dry
nitrogen. Solvents were dried by passage through activated alumina
towers and degassed before use. All solvents were stored over potassium
mirrors (with the exception of THF, which was stored over activated 4 Å
molecular sieves). Deuterated solvents were distilled from potassium,
degassed by three freezeꢀpumpꢀthaw cycles, and stored under nitro-
gen. The compounds [Li{HC(PPh2NSiMe3)2}]2,2,3 [MOR] (M = Rb, Cs;
OR = 2-ethylhexoxide),30 H2C(PPh2NAd)2,36 [Na(Bn)],38 [K(Bn)],39
[Cs(Bn)],14 and [La(I)3(THF)4]43 were prepared according to pub-
lished procedures. ButLi was purchased from Aldrich as a 1.7 M solution
in pentane, the solvent was removed in vacuo, and the resultant white
solid was stored in the glovebox.
bis(iminophosphorano)methanide scaffold adopts a typical dis-
torted twist-boat conformation upon coordination in both 9 and
10,1 with the methanide carbon displaced from the P2N2 least-
squares plane by 0.632 Å in both complexes and lanthanum
displaced 0.429 Å for 9 and 0.721 Å for 10. The methanide
framework of [La{CH(PPh2NSiMe3)2}{N(Ph2P)2}(Cl)] exhi-
bits similar parameters, with the methanide carbon displaced
0.617 Å and lanthanum displaced 0.233 Å from the P2N2 least-
squares plane in this complex.44 [La{CH(PPh2NSiMe3)2}-
{N(SiHMe2)2}2] [LaꢀC 2.875(4) Å and LaꢀN 2.536 (mean) Å;
PꢀCꢀP 135.7(2)° and NꢀLaꢀN 112.05(9)°]44 and [La{CH-
(PPh2NSiMe3)2}{N(Ph2P)2}(Cl)] [LaꢀC 2.802(4) Å and
LaꢀN 2.500(4) (mean) Å; PꢀCꢀP 138.1(2)° and NꢀLaꢀN
117.32(11)°]45 exhibit comparable PꢀCꢀP and NꢀLaꢀN
angles, LaꢀC distances, and endocyclic PꢀC and PꢀN bond
lengths to 9 [La(1)ꢀC(1) 2.859(8) Å and LaꢀN 2.438(6)
(mean) Å; P(1)ꢀC(1)ꢀP(2) 135.9(5)° and N(1)ꢀLa(1)ꢀ
N(2) 111.9(2)°] and 10 [La(1)ꢀC(1) 2.826(4) Å and LaꢀN
2.412(3) (mean) Å; P(1)ꢀC(1)ꢀP(2) 137.1(2)° and N(1)ꢀ
La(1)ꢀN(2) 114.73(12)°], although the LaꢀN distances of 9
and 10 are considerably shorter. The La(1)ꢀC(1) distances of 9
and 10 are relatively long, but within the reported range
(2.277ꢀ3.388 Å).32 Two iodides and one molecule of THF
complete the coordination spheres of 9 and 10, with 10
The 1H, 13C, 31P, 29Si, and 7Li NMR spectra were recorded on a Bruker
400 spectrometer operating at 400.2, 100.6, 162.0, 79.5, and 155.5 MHz,
respectively; chemical shifts are quoted in parts per million and are relative
to TMS (1H, 13C, and 29Si), external 85% H3PO4 (31P), and external 1.0 M
LiCl (7Li). FTIR spectra were recorded on a Bruker Tensor 27 spectro-
meter. Elemental microanalyses were carried out by Mr. Stephen Boyer at
the Microanalysis Service, London Metropolitan University, U.K.
Synthesis of [Rb{HC(PPh2NSiMe3)2}(THF)2] (1). Rubidium
2-ethylhexoxide (1.0 M in THF, 2.0 mL, 2.0 mmol) was added to a
precooled (ꢀ78 °C) slurry of [Li{HC(PPh2NSiMe3)2}]2 (1.27 g, 1.0
mmol) in THF (30 mL). The mixture was slowly allowed to warm to
room temperature with stirring over 24 h. Volatiles were removed in
vacuo and the resulting solid washed with hexane to afford 1 as a white
powder. Recrystallization from hot THF (1 mL) afforded 1 as pale
yellow crystals on cooling to room temperature. Yield: 0.53 g, 34%. Anal.
Calcd for C39H55N2O2P2RbSi2: C, 59.49; H, 7.04; N, 3.56. Found: C,
59.35; H, 7.17; N, 3.49. 1H NMR (d6-benzene, 298 K): δ 0.19 (s, 18H,
displaying four additional La
CꢀH agostic interactions
3 3 3
with methylene units of the N-adamantyl groups, similar to
6ꢀ8. Again, this was evidenced by acute LaꢀCꢀH angles,
short La
H contacts [2.770(4)ꢀ3.069(4) Å] and short
3 3 3
2
La
C distances [3.139(4)ꢀ3.253(4) Å].
Si(CH3)3), 1.54 (m, 8H, OCH2CH2), 1.92 (t, JPH = 2.6 Hz, 1H,
3 3 3
HCP2), 3.67 (m, 8H, OCH2CH2), 7.24 (t, 3JHH = 7.2 Hz, 4H, p-Ar-CH),
3
7.27 (m, JHH = 7.2 Hz, 8H, m-Ar-CH), 8.11 (m, 8H, o-Ar-CH).
’ SUMMARY AND CONCLUSIONS
13C{1H} NMR (d6-benzene, 298 K): δ 4.50 (Si(CH3)3), 23.39 (t, JPC
=
Heavy group 1 methanide complexes, namely, [Rb{HC-
(PPh2NSiMe3)2}(THF)2] (1),[Cs{HC(PPh2NSiMe3)2}(DME)2]
(2), [Rb{HC(PPh2NAd)2}(THF)2] (7), and [Cs{HC(PPh2N-
Ad)2}(DME)2] (8), have been prepared by treatment of the
134.8 Hz, HCP2), 25.56 (OCH2CH2), 67.57 (OCH2CH2), 127.52
(m-Ar-C), 128.65 (p-Ar-C), 131.39 (o-Ar-C), 143.61, 144.59 (ipso-Ar-C).
31P{1H} NMR (d6-benzene, 298 K): δ 11.87 (HCP2). 29Si{1H} NMR
(d6-benzene, 298 K): δ ꢀ17.08 (v t, 2JSiP = 6.4 Hz, SiMe3). FTIR v/cmꢀ1
5321
dx.doi.org/10.1021/om200553s |Organometallics 2011, 30, 5314–5325

Organometallics
ARTICLE
(Nujol): 1589 (w, br), 1260 (s), 1173 (m), 1097 (m), 1054 (m, br), 862
(m), 826 (m), 803 (m), 743 (m), 696 (m).
THF (3 mL) afforded crystalline 6. Yield: 0.87 g, 50%. Anal. Calcd for
C53H67KN2O2P2: C, 73.72; H, 7.81; N, 3.24. Found: C, 73.68; H, 7.93;
1
N, 3.19. H NMR (d6-benzene, 298 K): δ 1.53 (m, 8H, OCH2CH2),
Synthesis of [Cs{HC(PPh2NSiMe3)2}(DME)2] (2). Cesium
2-ethylhexoxide (1.0 M in toluene, 2.0 mL, 2.0 mmol) was added to a
precooled (ꢀ78 °C) slurry of [Li{HC(PPh2NSiMe3)2}]2 (1.27 g, 1.0
mmol) in toluene (30 mL). The mixture was slowly allowed to warm to
room temperature with stirring over 24 h. Volatiles were removed in
vacuo and the resulting solid washed with hexane to afford [Cs{HC-
(PPh2NSiMe3)2}] as a white powder. Yield: 1.04 g, 75%. Recrystalliza-
tion from hot DME (1.5 mL) afforded 2 as pale yellow crystals on
cooling to ꢀ30 °C. Anal. Calcd for C39H59CsN2O4P2Si2: C, 53.79; H,
6.83; N, 3.22. Found: C, 53.89; H, 6.97; N, 3.16. 1H NMR (d6-benzene,
298 K): δ 0.23 (s, 18H, Si(CH3)3), 1.84 (t, 2JPH = 2.2 Hz, 1H, HCP2),
3.22 (s, 12H, CH3OCH2), 3.39 (m, 8H, CH3OCH2), 7.27 (m, 4H, p-Ar-
CH), 7.29 (m, 8H, m-Ar-CH), 8.10 (m, 8H, o-Ar-CH). 13C{1H} NMR
(d6-benzene, 298 K): δ 4.63 (Si(CH3)3), 23.44 (t, JPC = 145.9 Hz,
HCP2), 58.42 (CH3OCH2), 71.91 (CH3OCH2), 127.98 (m-Ar-C),
129.07 (p-Ar-C), 131.38 (o-Ar-C), 143.71, 144.65 (ipso-Ar-C). 31P{1H}
NMR (d6-benzene, 298 K): δ 10.73 (HCP2). 29Si{1H} NMR (d6-
benzene, 298 K): δ ꢀ17.19 (v t, 2JSiP = 6.7 Hz, SiMe3). FTIR v/cmꢀ1
(Nujol): 1589 (w, br), 1260 (s), 1098 (s, br), 1022 (s, br), 863 (m), 800
(s), 741 (w), 724 (w), 696 (w).
Synthesis of [Li{HC(PPh2NAd)2}]2 (4). Toluene (20 mL) was
added to a precooled (ꢀ78 °C) mixture of 3 (0.477 g, 0.7 mmol) and
ButLi (0.045 g, 0.7 mmol), which turned orange upon warming to room
temperature and stirring for 16 h. Volatiles were removed in vacuo to
give crude 4 as an orange solid. Colorless crystals of 4 were obtained
from a saturated toluene solution. Yield: 0.17 g, 35%. Anal. Calcd for
C90H102Li2N4P4: C, 77.54; H, 8.54; N, 4.02. Found: C, 77.67; H, 8.55;
N, 3.97. 1H NMR (d6-benzene, 298 K): δ 1.68 (br m, 12H, CH2(CH)2),
1.96 (br m, 12H, NCCH2CH), 2.07 (br m, 6H, CH(CH2)3), 7.17 (br m,
12H, m- and p-Ar-CH), 7.97 (br m, 8H, o-Ar-CH), HCP2 not observed.
13C{1H} NMR (d6-benzene, 298 K): δ 30.81 (CH(CH2)3), 37.00
(CH2(CH)2), 49.56 (NCCH2CH), 52.33 (NC(CH2)3), 127.57 (m-
Ar-C), 129.01 (p-Ar-C), 132.56 (m, o-Ar-C), HCP2 and ipso-Ar-C not
observed. 31P{1H} NMR (d6-benzene, 298 K): δ 10.53 (br s, HCP2).
7Li{1H} NMR (d6-benzene, 298 K): δ 2.32 (br s, LiHCP2). FTIR v/
cmꢀ1 (Nujol): 1589 (w, br), 1261 (m), 1180 (m), 1096 (s), 1028 (s, br),
800 (m), 743 (m), 709 (m), 697 (m).
1.64 (t, 2JPH = 3.4 Hz, 1H, HCP2), 1.70 (br m, 12H, CH2(CH)2), 1.77
(br m, 12H, NCCH2CH), 2.09 (br m, 6H, CH(CH2)3), 3.67 (m, 8H,
OCH2CH2), 7.23 (t, 3JHH = 7.8 Hz, 4H, p-Ar-CH), 7.30 (m, 3JHH = 7.8
3
Hz, 8H, m-Ar-CH), 8.25 (t, JHH = 7.8 Hz, 8H, o-Ar-CH). 13C{1H}
NMR (d6-benzene, 298 K): δ 25.55 (OCH2CH2), 26.95 (t, JPC = 141.9
Hz, HCP2), 30.95 (CH(CH2)3), 37.13 (CH2(CH)2), 49.37 (NCCH-
2CH), 52.09 (NC(CH2)3), 67.57 (OCH2CH2), 126.99 (m-Ar-C),
128.21 (p-Ar-C), 132.43 (br, o-Ar-C), 145.18, 146.05 (ipso-Ar-C). 31P-
{1H} NMR (d6-benzene, 298 K): δ 4.90 (s, HCP2). FTIR v/cmꢀ1
(Nujol): 1558 (w, br), 1261 (m), 1168 (m), 1092 (s), 1026 (s, br), 873
(w), 800 (s), 736 (w), 722 (w), 696 (w).
Synthesis of [Rb{HC(PPh2NAd)2}(THF)2] (7). Rubidium
2-ethylhexoxide (1.0 M in THF, 2.0 mL, 2.0 mmol) was added to a
precooled (ꢀ78 °C) slurry of 4 (1.38 g, 1.0 mmol) in THF (30 mL).
The mixture was slowly allowed to warm to room temperature with
stirring over 24 h. Volatiles were removed in vacuo and the resulting
solid washed with hexane to afford 7 as a yellow powder. Recrystalliza-
tion from hot THF (1.5 mL) afforded 7 0.5C7H8 as crystals on cooling
3
to ꢀ30 °C. Yield: 0.95 g, 52%. Anal. Calcd for C53H67N2O2P2Rb: C,
70.61; H, 7.22; N, 2.99. Found: C, 70.54; H, 7.27; N, 2.86. 1H NMR (d6-
benzene, 298 K): δ 1.54 (m, 8H, OCH2CH2), 1.59 (t, 2JPH = 2.9 Hz, 1H,
HCP2), 1.76 (br m, 12H, CH2(CH)2), 1.81 (br m, 12H, NCCH2CH),
2.23 (br m, 6H, CH(CH2)3), 3.68 (m, 8H, OCH2CH2), 7.23 (t, 3JHH
=
7.6 Hz, 4H, p-Ar-CH), 7.31 (m, 3JHH = 7.6 Hz, 8H, m-Ar-CH), 8.28 (m,
8H, o-Ar-CH). 13C{1H} NMR (d6-benzene, 298 K): δ 25.58 (t, JPC
=
133.8 Hz, HCP2), 30.88 (CH(CH2)3), 36.99 (CH2(CH)2), 49.56
(NCCH2CH), 52.34 (NC(CH2)3), 127.16, 127.69 (m-Ar-C), 128.17,
129.98 (p-Ar-C), 132.49, 132.64 (o-Ar-C), 145.41, 146.28 (ipso-Ar-C).
31P{1H} NMR (d6-benzene, 298 K): δ 4.06 (s, HCP2). FTIR v/cmꢀ1
(Nujol): 1600 (w, br), 1302 (w), 1261 (s), 1096 (s, br), 1026 (s, br), 871
(w), 801 (s), 737 (w), 721 (w), 697 (w).
Synthesis of [Cs{HC(PPh2NAd)2}(DME)2] (8). THF (30 mL)
was added to precooled (ꢀ78 °C) mixture of 4 (1.37 g, 1.0 mmol) and
[Cs(Bn)] (0.45 g, 2.0 mmol) to give an orange solution. The mixture
was slowly allowed to warm to room temperature with stirring over 24 h.
Volatiles were removed in vacuo and the resulting solid washed with
hexane to afford [Cs{HC(PPh2NAd)2}(THF)n] as an orange powder.
Recrystallization from hot DME (4 mL) afforded crystalline
Synthesis of [Na{HC(PPh2NAd)2}(THF)2] (5). THF (30 mL)
was added to a precooled (ꢀ78 °C) mixture of 3 (2.05 g, 3.0 mmol) and
[Na(Bn)] (0.34 g, 3.0 mmol) to give a yellow solution. The mixture was
slowly allowed to warm to room temperature with stirring over 24 h.
Volatiles were removed in vacuo and the resulting solid washed with
hexane to afford crude 5 as a yellow powder. Recrystallization from hot
THF (2 mL) gave crystalline 5. Yield: 1.10 g, 43%. Anal. Calcd for
C53H67N2NaO2P2: C, 74.97; H, 7.95; N, 3.30. Found: C, 74.99; H, 7.49;
8 0.5C4H10O2 on cooling to ꢀ30 °C. Yield: 0.95 g, 52%. Anal. Calcd
3
for C55H76CsN2O5P2 (8 0.5C4H10O2): C, 63.50; H, 7.37; N, 2.69.
3
Found: C, 63.68; H, 7.42; N, 2.86. 1H NMR (d8-THF, 298 K): δ 1.71 (br
m, 12H, CH2(CH)2), 1.83 (br m, 12H, NCCH2CH), 1.95 (br m, 3H,
CH(CH2)3), 2.03 (br m, 3H, CH(CH2)3), 2.15 (br s, 1H, HCP2), 7.46
(br m, 8H, m-Ar-CH), 7.52 (d, 3JHH = 7.2 Hz, 4H, o-Ar-CH), 7.61 (t,
3JHH = 7.2 Hz, 2H, p-Ar-CH), 8.05 (t, 3JHH = 7.6 Hz, 2H, p-Ar-CH), 8.28
1
N, 3.18. H NMR (d6-benzene, 298 K): δ 1.50 (m, 8H, OCH2CH2),
(br m, 4H, o-Ar-CH). 13C{1H} NMR (d8-THF, 298 K): δ 23.99 (t, JPC
=
1.61 (br s, 1H, HCP2), 1.70 (br m, 12H, CH2(CH)2), 1.95 (br m, 12H,
NCCH2CH), 2.10 (br m, 6H, CH(CH2)3), 3.68 (m, 8H, OCH2CH2),
7.23 (br m, 12H, m- and p-Ar-CH), 8.16 (br m, 8H, o-Ar-CH). 13C{1H}
NMR (d6-benzene, 298 K): δ 25.46 (OCH2CH2), 30.95 (CH(CH2)3),
37.03 (CH2(CH)2), 49.42 (NCCH2CH), 51.95 (NC(CH2)3), 67.81
(OCH2CH2), 127.15 (m-Ar-C), 128.05 (p-Ar-C), 132.45 (m, o-Ar-C),
143.78, 144.53 (ipso-Ar-C), HCP2 not observed. 31P{1H} NMR (d6-
benzene, 298 K): δ 9.45 (br s, HCP2). FTIR v/cmꢀ1 (Nujol): 1589 (w),
1261 (m), 1208 (m), 1094 (s), 1025 (s, br), 876 (w), 800 (s), 741 (w),
722 (w), 696 (w).
Synthesis of [K{HC(PPh2NAd)2}(THF)2] (6). THF (30 mL)
was added to a precooled (ꢀ78 °C) mixture of 3 (1.37 g, 2.0 mmol) and
[K(Bn)] (0.26 g, 2.0 mmol) to give a yellow solution. The mixture was
slowly allowed to warm to room temperature with stirring over 24 h.
Volatiles were removed in vacuo and the resulting solid washed with
hexane to afford crude 6 as a yellow powder. Recrystallization from hot
134.8 Hz, HCP2), 28.85, 29.00 (CH(CH2)3), 34.88, 35.09 (CH2-
(CH)2), 46.66, 47.22 (NCCH2CH), 49.89, 50.39 (NC(CH2)3), 124.58
(m-Ar-C), 125.25, 125.68 (p-Ar-C), 130.48, 130.71 (o-Ar-C), 143.92,
144.82 (ipso-Ar-C). 31P{1H} NMR (d8-THF, 298 K): δ ꢀ0.58 (s,
HCP2). FTIR v/cmꢀ1 (Nujol): 1586 (w, br), 1348 (m), 1301 (m), 1260
(m), 1216 (s, br), 1093 (s), 1033 (m), 940 (m), 874 (m), 851 (m), 811
(m), 739 (m), 698 (m).
Synthesis of [La{HC(PPh2NSiMe3)2}(I)2(THF)] (9). THF
(25 mL) was added to a precooled (0 °C) mixture of [La(I)3(THF)4]
(4.04 g, 5.0 mmol) and 1 (3.43 g, 5.0 mmol). The resulting colorless
suspension was allowed to warm to room temperature with stirring over
20 h. The suspension was filtered and solvents removed in vacuo to yield
9 as a white powder. Yield: 4.21 g, 77%. Crystallization of a small portion
from toluene afforded colorless crystals of 9 0.5C7H8. Anal. Calcd for
3
C39H55I2LaN2O2P2Si2: C, 42.78; H, 5.07; N, 2.56. Found: C, 43.12; H,
5322
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Organometallics
ARTICLE
Table 2. Crystallographic Data for 1ꢀ5
1
2
3
4
5
formula
fw
C
39H55N2O2P2RbSi2
C39H59CsN2O4P2Si2
870.91
C45H52N2P2
682.83
C90H102Li2N4P4
1377.52
C53H67N2NaO2P2
849.02
787.44
cryst size, mm
cryst syst
space group
a, Å
0.23 ꢁ 0.17 ꢁ 0.17
monoclinic
P21/n
0.50 ꢁ 0.36 ꢁ 0.23
monoclinic
P21/c
0.31 ꢁ 0.20 ꢁ 0.17
triclinic
0.18 ꢁ 0.11 ꢁ 0.09
orthorhombic
Pna21
0.73 ꢁ 0.30 ꢁ 0.25
monoclinic
P21/c
P1
10.5328(5)
17.2302(9)
23.0134(12)
13.8885(2)
16.7771(4)
38.3042(5)
10.5879(11)
11.1951(12)
16.3420(12)
107.630(8)
102.177(8)
92.073(9)
1794.1(3)
2
27.3090(7)
12.5276(3)
22.2817(6)
29.1701(4)
20.3182(3)
23.9244(3)
b, Å
c, Å
α, °
β, °
γ, °
V, Å3
94.0980(10)
96.1663(13)
105.7572(14)
4165.8(4)
4
8873.6(3)
8
7622.9(3)
4
13 646.8(3)
12
Z
F
calcd, g cmꢀ3
μ, mmꢀ1
1.256
1.304
1.264
1.200
1.240
1.356
8.006
1.358
1.279
1.289
no. of reflns measd
no. of unique reflns, Rint
no. of reflns with F2 > 2σ(F2)
transm coeff range
R, Rwa (F2 > 2σ(F2))
R, Rwa (all data)
Sa
24 588
34 781
12 829
19 317
63 777
9393, 0.0213
7269
17 323, 0.0408
15 797
7038, 0.0605
6003
10 402, 0.0452
8860
27 221, 0.025
23 818
0.637ꢀ0.746
0.0372, 0.0906
0.0559, 0.0990
1.032
0.134ꢀ0.574
0.0484, 0.1261
0.0532, 0.1261
1.077
0.749ꢀ1.185
0.0511, 0.1356
0.0596, 0.1449
1.039
0.876ꢀ1.008
0.0499, 0.1128
0.0630, 0.1192
1.049
0.571ꢀ1.863
0.0379, 0.0965
0.0445, 0.102
1.03
parameters
514
926
442
902
1621
max, min diff map, e Åꢀ3
0.676, ꢀ0.551
1.317, ꢀ1.260
0.675, ꢀ0.572
0.506, ꢀ0.514
0.53, ꢀ0.38
a Conventional R = ∑||Fo| ꢀ |Fc||/∑|Fo|; Rw = [∑w(Fo ꢀ Fc2)2/∑w(Fo2)2]1/2; S = [∑w(Fo ꢀ Fc2)2/no. data ꢀ no. params)]1/2 for all data.
2
2
4.75; N, 2.53. 1H NMR (d6-benzene, 298 K): δ 0.36 (s, 18H, Si(CH3)3),
1.53 (m, 8H, OCH2CH2), 3.17 (t, 2JPH = 8.2 Hz, 1H, HCP2), 4.10 (m,
8H, OCH2CH2), 7.05 (m, 8H, m-Ar-CH), 7.19 (m, 4H, p-Ar-CH), 7.65
(m, 4H, o-Ar-CH), 7.90ꢀ8.25 (br, 4H, o-Ar-CH). 13C{1H} NMR
(d6-benzene, 298 K): δ 2.40 (Si(CH3)3), 12.86 (t, JPC = 118.9 Hz,
HCP2), 25.18 (OCH2CH2), 70.54 (OCH2CH2), 128.06, 128.43 (m-Ar-
C), 131.01 (p-Ar-C), 131.96 (o-Ar-C), ipso-Ar-C not observed. 31P{1H}
NMR (d6-benzene, 298 K): δ 17.63 (s, HCP2). 29Si{1H} NMR
(d6-benzene, 298 K): δ ꢀ4.86 (s, SiMe3). FTIR v/cmꢀ1 (Nujol): 1589
(w, br), 1310 (w), 1261 (s), 1114 (s), 1089 (s), 1025 (s), 984 (m), 836
(s), 801 (s), 722 (m), 693 (m), 659 (m), 606 (w). The preparation of 9
can be accomplished utilizing 2 instead of 1, giving a similar yield of 9.
Synthesis of [La{HC(PPh2NAd)2}(I)2(THF)] (10). THF (20 mL)
was added to a precooled (0 °C) mixture of [La(I)3(THF)4] (1.62 g,
2.0 mmol) and 6 (1.60 g, 2.0 mmol). The resulting brown suspension
was allowed to warm to room temperature with stirring over 20 h. The
suspension was filteredand volatiles removedin vacuo to yield 10 as an off-
white powder. Recrystallization from hot THF (11 mL) afforded, on
NMR (d6-benzene, 298 K): δ 12.11 (s, HCP2). FTIR v/cmꢀ1 (Nujol):
1587(w, br), 1304 (w), 1261 (m), 1226 (w), 1186(w), 1143(s), 1104 (s),
1020 (s), 992 (m), 875 (w), 846 (m), 801 (m), 764 (w), 745 (w), 720 (w),
712 (w), 693 (w), 627 (m).
X-ray Crystallography. Crystal data for compounds 1ꢀ10 are
given in Tables 2 and 3, and further details of the structure determina-
tions are in the Supporting Information. Bond lengths and angles are
listed in Table 1. Crystals were examined variously on a Bruker APEX
CCD area detector diffractometer using graphite-monochromated Mo
Kα radiation (λ = 0.71073 Å), or on an Oxford Diffraction SuperNova
Atlas CCD diffractometer using mirror-monochromated CuKα radia-
tion (λ = 1.5418 Å). Intensities were integrated from data recorded on
0.3 (APEX) or 1° (SuperNova) frames by ω rotation. Cell parameters
were refined from the observed positions of all strong reflections in each
data set. Semiempirical absorption correction based on symmetry-
equivalent and repeat reflections (APEX) or Gaussian grid face-indexed
absorption correction with a beam profile correction (Supernova) was
applied. The structures were solved variously by direct and heavy atom
methods and were refined by full-matrix least-squares on all unique F2
values, with anisotropic displacement parameters for all non-hydrogen
atoms, and with constrained riding hydrogen geometries; Uiso(H) was
set at 1.2 (1.5 for methyl groups) times Ueq of the parent atom. The
methanide hydrogens were initially located in the Fourier difference map
to confirm the methanide geometries and were subsequently idealized
and refined using a riding model. The largest features in final difference
syntheses were close to heavy atoms and were of no chemical signifi-
cance. Highly disordered solvent molecules of crystallization in
7 0.5C7H8 and 8 0.5C4H10O2 could not be modeled and were treated
cooling, colorless crystals of 10 1.5C4H8O. Yield: 0.94 g, 38%. Anal. Calcd
3
3
for C55H71I2LaN2O2.5P2 (10 1.5C4H8O): C, 52.65; H, 5.70; N, 2.23.
Found: C, 52.58; H, 5.76; N, 2.08. 1H NMR (d6-benzene, 298 K): δ 1.26
(br m, 12H, CH2(CH)2), 1.33 (br m, 6H, NCCH2CH), 1.70 (m, 4H,
OCH2CH2), 1.85 (br m, 6H, NCCH2CH), 2.11 (br m, 6H, CH(CH2)3),
3.08 (br m, 1H, HCP2), 3.95 (m, 4H, OCH2CH2), 6.64 (vt, 3JHH = 7.2 Hz,
4H, m-Ar-CH), 6.72 (vt, 3JHH = 7.2 Hz, 2H, p-Ar-CH), 6.89 (vt, 3JHH = 7.2
Hz, 2H, p-Ar-CH), 6.95 (vt, 3JHH = 7.2 Hz, 4H, m-Ar-CH), 7.64 (br m, 4H,
o-Ar-CH), 7.98 (br m, 4H, o-Ar-CH). 13C{1H} NMR (d6-benzene, 298
K): δ 11.15 (t, JPC = 139.5 Hz, HCP2), 25.13 (OCH2CH2), 30.15
(CH(CH2)3), 36.19 (CH2(CH)2), 45.90 (NCCH2CH), 57.32 (NC-
(CH2)3), 71.14 (OCH2CH2), 127.53, 128.42 (m-Ar-C), 130.83, 131.07
(p-Ar-C), 131.67, 134.94 (o-Ar-C), 137.93, 138.41 (ipso-Ar-C). 31P{1H}
3
3
with the Platon SQUEEZE procedure.46 Programs were Bruker AXS
SMART47 and CrysAlisPro48 (control) and Bruker AXS SAINT47 and
CrysAlisPro48 (integration), and SHELXTL49 and OLEX250 were
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ARTICLE
Table 3. Crystallographic Data for 6ꢀ10
6
7 0.5C7H8
8 0.5C4H10O2
9 0.5C7H8
10 1.5C4H8O
3
3
3
3
formula
C
53H67KN2O2P2
C53H67N2O2P2Rb
C53H71CsN2O4P2
C35H47I2LaN2OP2Si2
C49H59I2LaN2OP2
0.5C7H8
0.5C4H10O2
0.5C7H8
1.5C4H8O
3
3
3
3
fw
865.13
957.56
1040.03
1068.64
1254.79
cryst size, mm
cryst syst
space group
a, Å
0.46 ꢁ 0.40 ꢁ 0.36
monoclinic
P21
0.32 ꢁ 0.23 ꢁ 0.17
triclinic
0.68 ꢁ 0.48 ꢁ 0.33
monoclinic
P21/c
0.16 ꢁ 0.10 ꢁ 0.01
triclinic
0.15 ꢁ 0.11 ꢁ 0.06
monoclinic
P21/c
P1
P1
10.2558(11)
20.195(2)
10.8602(11)
11.2873(9)
14.3668(10)
16.6811(12)
80.260(6)
73.219(7)
71.248(7)
2443.7(3)
2
20.2678(17)
13.4245(14)
19.3640(11)
9.8191(4)
11.9347(4)
19.2510(9)
77.233(4)
77.040(4)
83.684(3)
2139.84(15)
2
13.0440(8)
39.599(2)
b, Å
c, Å
20.1193(12)
α, °
β, °
γ, °
V, Å3
94.588(2)
103.809(7)
90.184(1)
2242.1(4)
2
5116.4(8)
4
10 392.2(11)
4
Z
F
calcd, g cmꢀ3
μ, mmꢀ1
1.281
1.301
1.350
1.659
1.604
0.234
2.344
6.616
20.520
2.115
no. of reflns measd
no. of unique reflns, Rint
no. of reflns with F2 > 2σ(F2)
transm coeff range
R, Rwa (F2 > 2σ(F2))
R, Rwa (all data)
Sa
13715
20 870
20 645
9638
21 329
9332, 0.0135
9115
9705, 0.025
8908
10 016, 0.057
8295
7226, 0.0513
6203
53 355, 0.0247
17 199
0.63ꢀ0.75
0.0286, 0.0736
0.0293, 0.0741
1.058
0.624ꢀ0.891
0.0316, 0.0811
0.0342, 0.0829
1.06
0.117ꢀ0.632
0.0606, 0.163
0.0710, 0.173
1.06
0.461ꢀ0.912
0.0595, 0.160
0.0715, 0.170
1.08
0.597ꢀ0.746
0.0266, 0.0700
0.0288, 0.0712
1.11
parameters
546
545
594
441
1164
max, min diff map, e Åꢀ3
0.373, ꢀ0.169
0.68, ꢀ 0.43
1.63, ꢀ 2.13
2.39, ꢀ 2.39
1.72, ꢀ0.54
a Conventional R = ∑||Fo| ꢀ |Fc||/∑|Fo|; Rw = [∑w(Fo ꢀ Fc2)2/∑w(Fo2)2]1/2; S = [∑w(Fo ꢀ Fc2)2/no. data ꢀ no. params)]1/2 for all data.
2
2
employed for structure solution and refinement and for molecular
graphics.
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’ ASSOCIATED CONTENT
S
Supporting Information. CIF files giving crystallographic
b
data for 1ꢀ10. This material is available free of charge via the
Internet at http://pubs.acs.org.
’ AUTHOR INFORMATION
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Corresponding Author
*E-mail: stephen.liddle@nottingham.ac.uk.
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’ ACKNOWLEDGMENT
We thank the Royal Society for a University Research Fellow-
ship (S.T.L.), and the EPSRC, European Research Council,
and the University of Nottingham for generously supporting
this work.
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