Late transition-metal complexes of 2 Ph2PC6H 4NHC(O)CH2NHCO2Bz:Observation of three distinct ligation modes (κ1-P,κ2-P/N and κ3-P/N/N′)

Article abstract of DOI:10.1002/ejic.200801104

The one-step synthesis of the arnide-functionalised tertiary phosphane 2-Ph₂PC₆H₄NHC(O)CH₂NHCO ₂B z (BzCH₂Ph), 2-HH, by condensation of the known aminophosphane, 2-Ph₂PC₆H₄(NH₂) (1), with N-(benzyloxycarbonyl)-glycine and clicyclohexylcarbodiimide (DCC) in THF at: room temperature is reported. The new ligand 2-HH displays various coordination modes when complexed to a range of late transition-metal precursors. Hence κ¹-P-coordination for 2-HH is observed in the complexes ClAu(2-HH) (3), MCl₂(η⁵-Cp*)(2-HH) (M = Rh 4; Ir 5), RuCl₂(η²-p-cyrnene)(2-HH) (6), Pd(κ²-CN-C₁₂H₁₂N)Cl(2-HH) (7) and MC1₂(2-HH)₂ (M = Pd 8; Pt 9). Treatment of 8 or 9 with (BuOK in CH₃OH gave the bis-κ²-P/N-chelate complexes cis-M{2-Ph₂PC₆H₄NC(O)CH₂-NHCO ₂Bz}₂ (M = Pt 10; Pd 11) in which both monoanionic ligands 2-H^- are disposed in a cis geometry. The related nickel(II) complex is-Ni{2-Ph₂PC₆H₄NC(O)CH₂NHC0 ₂-Bz}₂ (12) was prepared from NiCl₂-6H ₂O, 2 equiv. of 2-HH and (BuOK in refluxing CH₃OH. Reaction of the piano-stool complex 5 with (BuOK in CH₃OH gave the chiral-at-metal complex Ir(η⁵-Cp*){2-Ph₂PC ₆H₄NC(O)CH₂NCO₂Bz} (14), present in solution as two diastereomers. A single-crystal X-ray diffraction study of 14 confirmed the κ³-P/N/N'-tridentate coordination mode. Under similar conditions the chiral-at-metal ruthenium (II) complex Ru (η⁶-p- cy men e) {2 - Ph₂PC₆H ₄NC(O)CH₂NCO₂Bz} (15) was prepared in which 2^2- functions efficiently as a dianionic tridentate ligand. All new compounds have been characterised by multinuclear NMR [³¹P{ ¹H}, ¹H], FT-IR, EI-MS, ES-MS and microanalysis. Furthermore, the X-ray structures of ten compounds have been determined and reveal, in the majority of cases, a strong propensity for the -NHC(O)CH ₂NHCO₂Bz group to engage in N-H...N, N-H...O and N-H...Cl hydrogen bonding. Wiley-VCH Verlag GmbH & Co, KGaA.

Full text of DOI:10.1002/ejic.200801104

FULL PAPER
DOI: 10.1002/ejic.200801104
Late Transition-Metal Complexes of 2-Ph2PC6H4NHC(O)CH2NHCO2Bz:
Observation of Three Distinct Ligation Modes (κ1-P,κ2-P/N and κ3-P/N/NЈ)
Mark R. J. Elsegood,[a] Andrew J. Lake,[a] and Martin B. Smith*[a]
Keywords: Coordination modes / Metallacycles / P ligands / Late-transition metals
The one-step synthesis of the amide-functionalised tertiary
phosphane 2-Ph2PC6H4NHC(O)CH2NHCO2Bz (Bz
CH2Ph), 2·HH, by condensation of the known aminophos-
phane, 2-Ph2PC6H4(NH2) (1), with N-(benzyloxycarbonyl)-
glycine and dicyclohexylcarbodiimide (DCC) in THF at room
complex 5 with tBuOK in CH3OH gave the chiral-at-metal
complex Ir(η5-Cp*){2-Ph2PC6H4NC(O)CH2NCO2Bz} (14),
present in solution as two diastereomers. A single-crystal X-
ray diffraction study of 14 confirmed the κ3-P/N/NЈ-tridentate
coordination mode. Under similar conditions the chiral-
=
temperature is reported. The new ligand 2·HH displays vari- at-metal
ruthenium(II)
complex
Ru(η6-p-cymene){2-
ous coordination modes when complexed to a range of late
transition-metal precursors. Hence κ1-P-coordination for
2·HH is observed in the complexes ClAu(2·HH) (3), MCl2(η5-
Cp*)(2·HH) (M = Rh 4; Ir 5), RuCl2(η6-p-cymene)(2·HH) (6),
Pd(κ2-CN-C12H12N)Cl(2·HH) (7) and MCl2(2·HH)2 (M = Pd 8;
Pt 9). Treatment of 8 or 9 with tBuOK in CH3OH gave the
bis-κ2-P/N-chelate complexes cis-M{2-Ph2PC6H4NC(O)CH2-
NHCO2Bz}2 (M = Pt 10; Pd 11) in which both monoanionic
ligands 2·H– are disposed in a cis geometry. The related
nickel(II) complex cis-Ni{2-Ph2PC6H4NC(O)CH2NHCO2-
Bz}2 (12) was prepared from NiCl2·6H2O, 2 equiv. of 2·HH
and tBuOK in refluxing CH3OH. Reaction of the piano-stool
Ph2PC6H4NC(O)CH2NCO2Bz} (15) was prepared in which
22– functions efficiently as a dianionic tridentate ligand. All
new compounds have been characterised by multinuclear
1
NMR [31P{1H}, H], FT-IR, EI-MS, ES-MS and microanalysis.
Furthermore, the X-ray structures of ten compounds have
been determined and reveal, in the majority of cases, a
strong propensity for the –NHC(O)CH2NHCO2Bz group to
engage in N–H···N, N–H···O and N–H···Cl hydrogen bond-
ing.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
ticularly applicable to P/N/N and P/N/O ligands. Many of
these ligands bind to metals in a neutral κ3-tridentate fash-
ion or ligate in a singly deprotonated form. Examples of κ3-
tridentate ligands that utilise all three donor centres in a
doubly deprotonated form are uncommon.[15] Herein, we
report the synthesis of an unsymmetrical κ3-P/N/NЈ-ligand
and demonstrate the flexible ligation behaviour of this new
ligand (in its neutral, monoanionic and dianionic forms)
through complexation studies towards linear, pseudo-tetra-
hedral and square-planar transition-metal centres. All com-
pounds have been characterized by multinuclear NMR and
FT-IR spectroscopy and in ten cases by single-crystal X-ray
diffraction studies.
Introduction
Coordination compounds of tridentate and tetradentate
ligands continue to attract much interest for their variable
ligating capabilities,[1–3] stabilisation of G-quadruplex
DNA,[4] sensor,[5] magnetic[6] and luminescent[7–9] proper-
ties and catalytic applications.[10] Various donor atom com-
binations have been documented that contain at least one
phosphorus donor atom and include for example P/N/C,[11]
P/C/N,[12] P/N/N,[13] P/N/O,[14] P/N/S,[15] P/N/P[16] and P/N/
Se.[17] Pincer ligands based on P/C/P[18] or P/Si/P[19] donor
sets afford interesting complexes, display unusual reactivity
and find applications in catalysis. Furthermore, P/O/O and
P/O/P ligands have been employed in self-assembly reac-
tions.[20,21] More recently the use of one or two soft sele-
nium donor atoms in tridentate ligands of the type Se/N/O
and Se/C/Se have been documented.[22,23]
Results and Discussion
Ligand Synthesis
One of the most common methods for the synthesis of
potentially tridentate ligand systems usually involves a
Schiff base condensation reaction.[24] This method is par-
The new ligand 2-Ph2PC6H4NHC(O)CH2NHCO2Bz (Bz
= CH2Ph) (2·HH) was synthesised in moderate yield (36%)
by condensation of the amine-functionalised tertiary phos-
phane 2-Ph2PC6H4(NH2) (1) with N-(benzyloxycarbonyl)-
glycine and DCC in THF (Scheme 1). Purification of the
crude material comprising 2·HH and unreacted 1 was read-
ily accomplished by recrystallisation from CH2Cl2/Et2O.
[a] Department of Chemistry, Loughborough University,
Loughborough, Leics, LE11 3TU, UK
Fax: +44-1509-223925
E-mail: m.b.smith@lboro.ac.uk
Supporting information for this article is available on the
WWW under http://www.eurjic.org or from the author.
1068
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 1068–1078

Flexible Ligation Behaviour of a Tridentate P/N/N Ligand
Scheme 1.
The 31P{1H} NMR spectrum of 2·HH shows two reso- Bz}, recently reported by us, in which the -PPh2 group
nances at δ(P) = –20.7/–21.3 ppm [cf. 2-Ph2PC6H4(NH2): points away from the N3 core.[25] The hydrogen H(1) forms
δ(P) = –20.3 ppm, CDCl3]. The formation of the new C– an intramolecular hydrogen bond to N(2) [N(1)···
N bond was further supported by the observation of new N(2) 2.720(2) Å, H(1)···N(2) 2.22(2) Å, N(1)–H(1)···N(2)
resonances at δ(H) = 5.12 (overlapping NH and OCH2 pro- 116.3(17)°] and H(2) intermolecularly H-bonds to O(1B)
1
tons) and a doublet at δ = 3.85 ppm (NHCH2) in the H [N(2)···O(1B) 2.927(2) Å, H(2)···O(1B) 2.09(2) Å, N(2)–
NMR spectrum. The FT-IR spectrum of 2·HH clearly H(2)···O(1B) 162(2)°. Symmetry operator: B: x + 1/2, y, –z
shows the presence of NH (3328 and 3264 cm–1) and CO + 3/2] leading to 1-D chains along the crystallographic a
(1721 and 1677 cm–1) functional groups. Oxidation of 2·HH direction (Figure 2).
with aqueous H2O2 gives a smooth conversion to the terti-
ary phosphane oxide 2a as inferred by two downfield 31P
resonances [δ(P) = 37.2 and 36.9 ppm]. The observation of
two similar phosphorus signals for 2a (and 2·HH), in the
region typically expected for tertiary phosphane oxides,
suggests closely related structures which we believe to be
conformers due to restricted rotation about either the NH–
C(O) or NH–C(O)O bonds.
To evaluate whether 2·HH is preorganised for metal-ion
coordination, an X-ray crystallographic study was per-
formed. The molecular structure of 2·HH (Figure 1) clearly
shows that C–N coupling [C(7)–N(1) = 1.417(2) Å, Table 1]
has resulted as previously indicated by the spectroscopic
data. Pyramidalisation around P(1) is clearly reflected in
the C–P–C bond angles which lie in the range 99.11(9)–
105.14(9)°. The donor atoms P(1), N(1) and N(2) essentially
all reside in the same plane and are positioned towards each
other. This finding contrasts with the X-ray crystal struc-
Figure 1. Molecular structure of 2·HH showing the N(1)–H(1)···
N(2) intramolecular H-bonding. All hydrogen atoms except H(1)
ture of 2-{Ph2PC6H4C(H)=N}C6H4{NHC(O)CH2NHCO2- and H(2) have been omitted for clarity.
Eur. J. Inorg. Chem. 2009, 1068–1078
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1069

M. R. J. Elsegood, A. J. Lake, M. B. Smith
FULL PAPER
Table 1. Selected bond lengths [Å] and angles [°] for compounds 2·HH, 2a, 3, 4·Et2O and 8.
2·HH
2a[a]
3
4·Et2O
(M = Rh)
8
(M = Au)
(M = Pd)
C(6)–N(1)
N(1)–C(7)
C(7)–O(1)
N(2)–C(9)
C(9)–O(2)
C(9)–O(3)
P(1)–O(7)
1.417(2)
1.354(2)
1.227(2)
1.355(3)
1.210(2)
1.348(2)
1.408(2) [1.4110(19)]
1.357(2) [1.3507(19)]
1.2190(19) [1.2234(19)]
1.342(2) [1.346(2)]
1.216(2) [1.2143(19)]
1.355(2) [1.3545(19)]
1.5023(11) [1.4989(11)]
1.428(4)
1.356(5)
1.225(4)
1.348(5)
1.208(5)
1.363(5)
1.411(11)
1.385(11)
1.221(14)
1.385(15)
1.171(14)
1.348(12)
1.418(4)
1.344(4)
1.220(4)
1.326(6)
1.209(5)
1.367(5)
M(1)–Cl(1)
M(1)–Cl(2)
M(1)–P(1)
2.3111(9)
2.4180(19)
2.4086(19)
2.353(2)
2.2999(8)
2.3288(8)
2.2326(9)
3.0926(9)
M(1)–M(1A)
M(1)–Ccentroid
C(6)–N(1)–C(7)
N(1)–C(7)–O(1)
N(2)–C(9)–O(2)
O(2)–C(9)–O(3)
P(1)–M(1)–Cl(1)
P(1Ј)–M(1)–Cl(1)
P(1)–M(1)–Cl(2)
Cl(1)–M(1)–Cl(2)
P(1)–M(1)–M(1A)
Cl(1)–M(1)–M(1A)
1.8343(34)
124.9(8)
122.5(10)
123.0(10)
128.9(11)
93.25(7)
130.32(17)
125.76(19)
125.15(19)
124.79(19)
128.37(14) [128.59(13)]
126.02(16) [125.74(15)]
125.03(16) [125.46(15)]
124.03(17) [125.22(15)]
123.9(3)
123.7(4)
125.8(4)
124.2(4)
169.99(3)
126.8(3)
124.5(3)
126.2(4)
123.3(4)
86.12(3)
93.88(3)
89.95(7)
89.56(8)
111.47(3)
74.70(2)
[a] Two independent molecules in the asymmetric unit. Symmetry operator: A: x + 1/2, y, –z + 3/2. Symmetry operator: Ј: –x + 1, –y +
1, –z + 1.
the phosphoryl oxygen [O(7) and O(8), respectively] atoms
[N(1)···N(2)2.743(2) Å,H(1)···N(2)2.280(18) Å,N(1)–H(1)···
N(2) 113.9(15)° and N(1)···O(7) 2.7394(17) Å, H(1)···O(7)
1.979(19) Å, N(1)–H(1)···O(7) 146.8(17)°. Equivalent pa-
rameters for the second independent molecule are N(3)···
N(4) 2.7580(18) Å, H(3)···N(4) 2.299(18) Å, N(3)–H(3)···
N(4) 112.8(14)° and N(3)···O(8) 2.7607(17) Å, H(3)···O(8)
1.974(19) Å, N(3)–H(3)···O(8) 149.1(16)°]. An intermo-
lecular H-bond further links molecules into chains [N(2)···
O(7A) 2.8782(19) Å, H(2)···O(7A) 2.05(2) Å, N(2)–H(2)···
O(7A) 161.8(18)° and N(4)···O(8B) 2.8824(17) Å, H(4)···
O(8B) 2.067(19) Å, N(4)–H(4)···O(8B) 169.4(17)°. Sym-
metry operators: A: –x + 1, –y, –z + 1, B: –x, –y + 1, –z].
Figure 2. Intermolecular N–H···O bonding in 2·HH. Symmetry op-
erator: A: x + 1/2, y, –z + 3/2. Only the N–H hydrogen atoms are
shown for clarity.
The structure of the phosphane oxide 2a (Figure 3) has
also been determined with selected bond lengths and angles
given in Table 1. Overall the structure is similar to 2·HH
with the exception of the newly formed P=O bond
[1.5023(11) Å and 1.4989(11) Å for the two independent
molecules]. In contrast with 2·HH, H(1) [and H(3)] are in-
volved in bifurcated intramolecular H-bonding with the
H(1)···N(2) and N(1)–H(1)···O(7) intramolecular H-bonding. All
secondary amine nitrogen [N(2) and N(4), respectively] and hydrogen atoms except H(1) and H(2) have been omitted for clarity.
Figure 3. Molecular structure of 2a showing the bifurcated N(1)–
1070
www.eurjic.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 1068–1078

Flexible Ligation Behaviour of a Tridentate P/N/N Ligand
Figure 4. Packing plot of 3 showing those H-atoms involved in H-bonding and the aurophilic interaction. Symmetry operators: A –x +
1, y, –z + 3/2, B –x + 1/2, –y + 1/2, –z + 1.
Complexation Studies
Compound 4·Et2O (Figure 5, Table 1) shows a classic pi-
ano-stool arrangement about the central RhIII centre com-
prising a pentahapto coordinated Cp*, two chlorides and a
monodentate bound phosphane 2·HH. Although no un-
usual structural features were observed there was an intra-
molecular N–H···Cl hydrogen bond [N(1)···Cl(2)
3.188(8) Å, H(1)···Cl(2) 2.35 Å, N(1)–H(1)···Cl(2) 159°].
This H-bond motif is similar to that found in 3.
κ1-P-Coordination
A range of late transition-metal complexes with 2·HH
were prepared (Scheme 1) either by substitution of a labile
ligand (tht for 3, cod for 8 and 9) or chloride-bridge cleav-
age of an organometallic dimer (as in the case of 4–7). All
the mononuclear complexes were isolated in good to excel-
lent yields (68–98%) and have been fully characterised by
NMR, FT-IR and microanalysis. The 31P{1H} NMR spec-
troscopic data for complexes 3–9 show the expected down-
field shifts upon P-coordination of 2·HH (see Exp. Sect.).
The X-ray structure of 3 (Figure 4, Table 1) clearly re-
veals coordination at P of an AuCl unit. The Au–Cl and
Au–P bond lengths are normal although the Cl–Au–P bond
angle [169.99(3)°] deviates some 10° from the ideal angle
expected for a linear geometry.[26,27] This “bending back”
can presumably be attributed to the strong aurophilic inter-
action [3.0926(9) Å] between two molecules of 3 leading to
a dimer pair.[27–29] Intermolecular hydrogen bonding be-
tween pendant NHC(O)CH2NHCO2Bz groups leads to a
classic head-to-tail arrangement [N(2)···O(1B) 3.034(4) Å,
H(2)···O(1B) 2.17(2) Å, N(2)–H(2)···O(1B) 168(4)°]. The re-
maining N(H) group within each aurophilic linked dimer is
involved in intramolecular N–H···Cl hydrogen bonding
Figure 5. Molecular structure of 4·Et2O. The intermolecular H-
bonded diethyl ether solvent has been omitted for clarity. Only the
phenyl ipso carbons on P(1) are shown.
The X-ray structure of 8 (Figure 6, Table 1) reveals a
[N(1)···Cl(1A) 3.347(3) Å, H(1)···Cl(1A) 2.52(2) Å, N(1)– trans stereochemistry of the two phosphane (2·HH) ligands.
H(1)···Cl(1A) 152(3)°]. The Pd–Cl [2.2999(8) Å] and Pd–P [2.3288(8) Å] bond
Figure 6. Packing plot of 8 showing the two H-bonding motifs. Symmetry operators: Ј: –x + 1, –y + 1, –z + 1; A: –x + 1, –y + 1,
–z.
Eur. J. Inorg. Chem. 2009, 1068–1078
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1071

M. R. J. Elsegood, A. J. Lake, M. B. Smith
FULL PAPER
lengths are normal and compare favourably with other 12 adopt a conformation best described as envelope with
PdCl2(PR3)2 complexes with a trans disposition.[30] The the metal atom at the tip of the flap and with hinge angles
–NHC(O)CH2N(H)CO2Bz dangling groups are clearly po- [M(1)/P(1)/N(1) vs. N(1)/C(6)/C(1)/P(1) and M(1)/P(2)/N(3)
sitioned above and below the PdCl2P2 coordination plane. vs. N(2)/C(34)/C(29)/P(2)] in the range 29.4–33.9°. The pen-
The hydrogen-bonding motif in 8 resembles that previously dant groups on N(1) and N(3) point away from each other
observed for the AuI complex 3. Hence H(1) forms an intra- and are involved in different hydrogen bonding arrange-
molecular N–H···Cl hydrogen bond [N(1)···Cl(1Ј) ments (Supporting Information). Hence H(4) is intramolec-
3.102(3) Å, H(1)···Cl(1Ј) 2.30(2) Å, N(1)–H(1)···Cl(1Ј) ular H-bound to O(4) [N···O 2.614(4) Å, 2.23(3) Å, 109(3)°
152(3)°]. Furthermore, the N(2)–H(2) and an adjacent car- for 10; N···O 2.619(3) Å, 2.24(3) Å, 110(2)° for 11; N···O
bonyl O(1) are involved in hydrogen bonding affording an 2.591(3) Å, 2.19(3) Å, 109(2)° for 12]. In contrast, the C(O)
R2 (10) ten-membered ring [N(2)···O(1A) 2.866(4) Å, H(2)··· and NH groups of the second chain are involved in inter-
2
O(1A) 2.01(3) Å, N(2)–H(2)···O(1A) 167(4)°]. Both these molecular H-bonding affording dimer pairs [N···O
H-bonds are stronger than those found in 3.
2.791(4) Å, 2.02(4) Å, 172(4)° for 10; N···O 2.786(3) Å,
2.00(3) Å, 173(3)° for 11; N···O 2.800(3) Å, 1.987(18) Å,
173(3)° for 12].
κ2-P/N-Coordination
Having established the classic κ1-P coordination mode
that would be expected for the tertiary phosphane 2·HH,
the ease by which this ligand could chelate transition metals
forming five-membered M–P–C–C–N metallacycles was ex-
plored.[31] Accordingly when compounds 8 or 9 were treated
with tBuOK in CH3OH the solids 10 or 11 were isolated in
high yields [Equation (1), R = C(O)CH2NHCO2Bz]. The
NiII complex 12 was obtained directly from NiCl2·6H2O,
2 equiv. of 2·HH and tBuOK in refluxing CH3OH. In all
cases the 31P{1H} NMR spectra of 10–12 showed new
Figure 7. Molecular structure of 10 (compounds 11 and 12 are iso-
downfield phosphorus resonances at δ(P) 19.7 (10), 42.2 structural and not shown). The phenyl rings on P(1) and P(2) have
(11) and 21.2 (12) ppm. Furthermore, the J(PtP) coupling
been removed for clarity.
constant for 10 was ca. 400 Hz less than found for 9 in
accord with P trans to N. Whilst attempts to prepare a clean
Table 2. Selected bond lengths [Å] and angles [°] for compounds
10–12.
sample of the single deprotonated chelate complex 13
failed, a few X-ray quality crystals of 13 were obtained and
the X-ray structure determined (vide infra).
10
(M = Pt)
11
12
(M = Pd)
(M = Ni)
M(1)–N(1)
M(1)–N(3)
M(1)–P(1)
M(1)–P(2)
C(6)–N(1)
N(1)–C(7)
C(7)–O(1)
N(2)–C(9)
C(9)–O(2)
2.089(2)
2.103(2)
2.2315(8)
2.2273(8)
1.425(4)
1.355(4)
1.233(3)
1.331(4)
1.218(4)
1.366(4)
1.415(4)
1.367(4)
1.222(4)
1.339(4)
1.209(4)
1.350(4)
96.89(9)
81.28(7)
168.31(7)
101.26(3)
82.16(7)
171.74(7)
2.0916(17)
2.1127(17)
2.2420(6)
2.2408(6)
1.421(3)
1.351(3)
1.237(3)
1.334(3)
1.214(3)
1.367(3)
1.415(3)
1.353(3)
1.233(3)
1.340(3)
1.205(3)
1.356(3)
98.47(7)
81.04(5)
167.73(5)
100.31(2)
82.04(5)
171.30(5)
1.933(2)
1.963(2)
2.1635(7)
2.1602(7)
1.427(3)
1.347(3)
1.232(3)
1.334(4)
1.213(3)
1.360(3)
1.420(3)
1.349(3)
1.232(3)
1.339(3)
1.209(3)
1.352(3)
97.05(9)
83.21(6)
165.77(7)
97.93(3)
84.59(6)
168.74(6)
C(9)–O(3)
C(34)–N(3)
N(3)–C(35)
C(35)–O(4)
N(4)–C(37)
C(37)–O(5)
C(37)–O(6)
N(1)–M(1)–N(3)
N(1)–M(1)–P(1)
N(1)–M(1)–P(2)
P(1)–M(1)–P(2)
(1)
The X-ray structures of 10–12 have each been determined
(Figure 7 for compound 10, Supporting Information for P(2)–M(1)–N(3)
P(1)–M(1)–N(3)
compounds 11 and 12). All three compounds are iso-
structural and comprise a central metal chelated by two, cis-
disposed, κ2-P/N-ligands. The M–P and M–N bond lengths
The X-ray structure of 13·Et2O has also been determined
(Table 2) are normal and are similar to previous documen- (Figure 8, Table 3). The asymmetric unit comprises two
ted cases.[31] Furthermore, the central metal is displaced by molecules of the platinum complex and two molecules of
0.0347 Å (10), 0.0341 Å (11) and 0.0259 Å (12) out of the Et2O (one independent molecule shown in Figure 8). Both
basal plane of the four donor atoms [P(1), P(2), N(1) and molecules display the expected square-planar geometry
N(3)]. In addition, both five-membered chelate rings in 10– comprising one κ1-P-monodentate, a κ2-P/N-didentate and
1072
www.eurjic.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 1068–1078

Flexible Ligation Behaviour of a Tridentate P/N/N Ligand
a chlorido ligand. The Pt lies 0.1197 Å (0.1084 Å for the κ3-P/N/NЈ-Coordination
second independent molecule) out of the basal plane. Both
To evaluate whether 2·HH could function effectively as
Pt–P distances are similar despite the different trans ligands
[Pt–P 2.2450(10) and 2.2421(10) Å for P trans to Cl; Pt–P
2.2666(11) and 2.2703(11) Å for P trans to NR2]. The Pt–
P–C–C–N chelate ring is markedly distorted with hinge
angles of 34.0° and 35.5° for the two independent mole-
cules. The NHC(O) hydrogen on the κ1-P-monodentate
bound ligand is intramolecularly H-bonded to the terminal
chloride [N···Cl 3.177(4), 3.165(4) Å, H···Cl 2.43(4),
2.38(4) Å, N–H···Cl 155(4), 169(4)°]. Furthermore, within
the same group, the NH hydrogen in the NHCO2Bz group
is involved in H-bonding to the Et2O solvate [N···O
2.972(5), 3.000(5) Å, H···O 2.21(4), 2.18(4) Å, N–H···O
165(5), 169(4)°]. The other chain on the κ2-P/N-chelate li-
a tridentate system, the IrIII complex 5 was treated with
tBuOK in refluxing CH3OH [Equation (2)]. The 31P{1H}
NMR spectrum of the crude material revealed two new
phosphorus signals at δ(P) 16.0 and 8.0 ppm in a 1.0:3.2
ratio. Both phosphorus resonances are assigned to the two
diastereomers of the chiral-at-metal complex Ir(η5-Cp*){2-
Ph2PC6H4NC(O)CH2NCO2Bz} (14) containing a κ3-dian-
ionic P/N/NЈ ligand. Similarly the RuII complex 6 gave, un-
der similar conditions, the chiral-at-metal complex Ru(η6-
p-cymene){2-Ph2PC6H4NC(O)CH2NCO2Bz} (15) in 80%
isolated yield. The 31P{1H} NMR spectrum of 15 showed
two new signals at δ(P) 50.2 and 46.6 ppm, in an approxi-
mate 1.0:1.0 ratio, consistent with the presence of two dia-
stereomers. Other characterising data are given in the Exp.
Sect.
gand forms a head-to-tail R2 (10) H-bonded ring [N···O
2
2.903(5), 2.973(4) Å, H···O 2.18(4), 2.16(4) Å, N–H···O
166(5), 160(4)°] (Supporting Information).
(2)
In order to establish unambiguously the coordination
mode of 2 we were fortunate to obtain a few crystals of 14
which indeed confirmed κ3-P/N/NЈ-coordination. The X-
ray structure of 14 (Figure 9, Table 4) confirms this triden-
tate coordination mode for 2. The ligand chelates forming
two five-membered rings, Ir(1)–P(1)–C(1)–C(6)–N(1) and
Ir(1)–N(2)–C(8)–C(7)–N(1), that display hinge angles of
30.4° [Ir(1)/P(1)/N(1) vs. P(1)/C(1)/C(6)/N(1)] and 25.3°
[Ir(1)/N(1)/N(2) vs. N(1)/C(7)/C(8)/N(2)]. The Ir(1)–P(1)
length is in the range typically expected[32] and the Ir(1)–
N(1)/N(2) distances are very similar. There are significant
differences between the P(1)–Ir(1)–N(1) [76.4(2)°] and P(1)–
Figure 8. Molecular structure of 13·Et2O showing one independent
molecule only. The diethyl ether solvent and all hydrogen atoms
except those on nitrogen have been omitted for clarity.
Table 3. Selected bond lengths [Å] and angles [°] for compound
13·Et2O.
13·Et2O[a]
Pt(1)–Cl(1)
Pt(1)–P(1)
Pt(1)–P(2)
Pt(1)–N(1)
C(6)–N(1)
N(1)–C(7)
C(7)–O(1)
N(2)–C(9)
C(9)–O(2)
2.3761(10) [2.3743(10)]
2.2450(10) [2.2421(10)]
2.2666(11) [2.2702(11)]
2.097(3) [2.088(3)]
1.423(5) [1.419(5)]
1.358(5) [1.362(5)]
1.242(5) [1.234(5)]
1.335(6) [1.346(6)]
1.219(6) [1.216(5)]
1.360(6) [1.361(5)]
1.411(5) [1.414(5)]
1.362(5) [1.358(5)]
1.213(5) [1.214(5)]
1.346(6) [1.345(5)]
1.210(5) [1.210(5)]
1.361(5) [1.360(5)]
90.21(9) [89.58(9)]
163.75(4) [164.42(4)]
89.22(4) [90.16(4)]
100.29(4) [100.18(4)]
80.60(9) [80.27(9)]
178.45(9) [179.02(9)]
C(9)–O(3)
C(34)–N(3)
N(3)–C(35)
C(35)–O(4)
N(4)–C(37)
C(37)–O(5)
C(37)–O(6)
Cl(1)–Pt(1)–N(1)
Cl(1)–Pt(1)–P(1)
Cl(1)–Pt(1)–P(2)
P(1)–Pt(1)–P(2)
P(1)–Pt(1)–N(1)
P(2)–Pt(1)–N(1)
Figure 9. Molecular structure of 14 showing the major disorder
component only. All hydrogen atoms removed for clarity. Only the
phenyl ipso carbon atoms on P(1) are shown.
[a] Two independent molecules in the asymmetric unit.
Eur. J. Inorg. Chem. 2009, 1068–1078
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1073

M. R. J. Elsegood, A. J. Lake, M. B. Smith
FULL PAPER
were recorded either with Bruker AC250 or DPX-400 FT spec-
trometers with chemical shifts (δ) reported relative to external TMS
or H3PO4. All NMR spectra (250 or 400 MHz) were recorded in
CDCl3 solutions unless otherwise stated. Elemental analyses (Per-
kin–Elmer 2400 CHN Elemental Analyzer) were performed by the
Loughborough University Analytical Service within the Depart-
ment of Chemistry.
Ir(1)–N(2) [97.5(3)°] bond angles presumably as a conse-
quence of the differing phenyl vs. alkyl backbones separat-
ing the P/N donor atoms. Within the Ir(1)–N(2)–C(8)–
C(7)–N(1) ring the Ir(1), N(1), C(7), C(8) atoms are co-
planar to within Ϯ0.03 Å whilst N(2) is the flap of an enve-
lope lying 0.58 Å out of this plane. For the other five-mem-
bered ring, N(1), C(6), C(1) and P(1) are co-planar to
within Ϯ0.02 Å whilst Ir(1) lies 0.98 Å out of this plane.
Preparation of 2-Ph2PC6H4NHC(O)CH2NHCO2Bz, (2·HH): A
solution of 1 (2.003 g, 7.222 mmol), N-(benzyloxycarbonyl)glycine
(1.511 g, 7.222 mmol) and 1,3-dicyclohexylcarbodiimide, DCC,
(1.594 g, 7.725 mmol) in THF (60 mL) was stirred at ambient tem-
perature, under nitrogen for 4 d. The solid was removed by fil-
tration, washed with some THF and the combined filtrate evapo-
rated to dryness. The residue was taken up in CH2Cl2 (25 mL),
passed through a small plug and Et2O (80 mL) added. The solid
2·HH was collected by suction filtration, washed with a small por-
tion of Et2O and dried. Yield 1.217 g, 36%. Selected data: 31P
NMR (CDCl3): δ = –20.7, –21 .3 (ratio 8.0:1.0) ppm. 1H NMR
(CDCl3): δ = 8.45 (s, 1 H, arom. H), 8.14 (m, 1 H, arom. H), 7.37–
7.26 (m, 15 H, arom. H), 7.08 (t, 1 H, arom. H), 6.92 (dt, 1 H,
Table 4. Selected bond lengths [Å] and angles [°] for compound 14.
14[a]
Ir(1)–P(1)
Ir(1)–N(1)
Ir(1)–N(2)
Ir(1)–Ccentroid
C(6)–N(1)
N(1)–C(7)
C(7)–O(1)
N(2)–C(9)
2.271(2)
2.085(8)
2.082(9)
1.8459(42)
1.409(11)
1.368(13)
1.232(12)
1.29(2)
C(9)–O(2)
C(9)–O(3)
1.37(2)
1.22(2)
3
arom. H), 5.12 (s, 3 H, overlapping OCH2 and NH), 3.79 (d, J =
P(1)–Ir(1)–N(1)
P(1)–Ir(1)–N(2)
N(1)–Ir(1)–N(2)
C(6)–N(1)–C(7)
N(1)–C(7)–O(1)
N(2)–C(9)–O(2)
O(2)–C(9)–O(3)
76.4(2)
97.5(3)
77.0(4)
120.0(8)
125.2(10)
120.7(15)
120.0(16)
4 Hz, 2 H, NCH ) ppm. FT-IR (KBr): ν = 3328, 3264 (NH), 1721
˜
2
(CO), 1677 (amide I), 1522 (amide II) cm–1. EI-MS: m/z = 468
[M+]. C28H25N2O3P (468.5): calcd. C 71.78, H 5.39, N 5.98; found
C 71.67, H 5.18, N 5.77.
2-Ph2P(O)C6H4NHC(O)CH2NHCO2Bz (2a): The tertiary phos-
phane oxide was prepared by oxidation of 2·HH (0.040 g,
0.085 mmol) with aq. H2O2 (27.5% w/w, 6 drops) in CDCl3. Yield
0.027 g, 66%. Selected data: 31P NMR (CDCl3): δ = 37.2, 36.9
[a] Major component.
1
(ratio 1:5.4) ppm. H NMR (CDCl3): δ = 11.30 (s, 1 H, NH), 8.47
(m, 1 H, arom. H), 7.61–6.90 (m, 18 H, arom. H), 5.40 (t, 1 H,
NH), 5.06 (s, 2 H, OCH2), 3.92 (d, J = 4 Hz, 2 H, NCH2) ppm.
Conclusions
3
FT-IR (KBr): ν = 3255 (NH), 1720 (CO), 1712, 1694 (amide I),
˜
In summary, we have shown that a new P/N/NЈ-function-
alised ligand 2·HH can display various coordination modes
dependant on the geometry of the transition-metal centre
(linear, square-planar or pseudo-tetrahedral). This flexibil-
ity in ligand geometry mirrors our previous studies with a
P/N/NЈ/NЈЈ-tetradentate system which likewise can adopt
numerous coordination motifs.[25] The amide functional
groups adopt various secondary hydrogen-bonding interac-
tions and in solution, we believe some of these compounds
exist as conformers due to hindered amide-bond rotation.
Further studies are in progress and will be reported in due
course.
1536 (amide II) 1153 (PO) cm–1. ES-MS: m/z = 485 [M + H+].
C28H25N2O4P (484.5): calcd. C 69.41, H 5.21, N 5.78; found C
69.40, H 5.21, N 5.70.
Preparation of AuCl{2-Ph2PC6H4NHC(O)CH2NHCO2Bz} (3):
2·HH (0.103 g, 0.220 mmol) was added to a CH2Cl2 (10 mL) solu-
tion of AuCl(tht) (0.071 g, 0.22 mmol). The colourless solution was
stirred for 20 min, concentrated under reduced pressure to ca. 1–
2 mL and Et2O (20 mL) and hexanes (20 mL) added. The solid 3
was collected by suction filtration and dried. Yield 0.147 g, 95%.
Selected data: 31P NMR (CDCl3): δ = 20.9 ppm. 1H NMR
(CDCl3): δ = 8.30 (s, 1 H, NH), 7.96 (m, 1 H, arom. H), 7.56–6.80
(m, 18 H, arom. H), 5.42 (br., 1 H, NH), 5.08 (s, 2 H, OCH2), 3.81
(d, 3J = 6 Hz, 2 H, NCH ) ppm. FT-IR (KBr): ν = 3362, 3274
˜
2
(NH), 1724 (CO), 1691 (amide I), 1506 (amide II), 318 (AuCl) cm–1.
ES-MS: m/z = 665 [M – Cl]. C28H25AuClN2O3P (700.9): calcd. C
47.98, H 3.60, N 4.00; found C 48.12, H 3.36, N 3.88.
Experimental Section
Materials: All reactions were carried out in air with the exception
of 2·HH whose synthesis was conducted under dry, oxygen-free
nitrogen. All solvents were distilled prior to use. The compound 2-
Ph2PC6H4(NH2) (1) was a kind donation from Dr S. M. Aucott
whereas AuCl(tht) (tht = tetrahydrothiophene),[33] MCl2(cod) (M
= Pt, Pd; cod = cycloocta-1,5-diene),[34] {RuCl2(η6-p-cymene)}2,[35]
Preparation of Ir(η5-Cp*)Cl2{2-Ph2PC6H4NHC(O)CH2NHCO2Bz}
(5): 2·HH (0.072 g, 0.154 mmol) was added to a CH2Cl2 (10 mL)
solution of {IrCl2(η5-Cp*)}2 (0.061 g, 0.077 mmol). The orange
solution was stirred for 20 min, passed through a small plug, con-
centrated under reduced pressure to ca. 1–2 mL and Et2O (10 mL)
added. The solid 5 was collected by suction filtration and dried.
Yield 0.130 g, 98%. Selected data: 31P NMR (CDCl3): δ = 0.0, –0.2
{MCl2(η5-Cp*)}2 (M
=
Rh, Ir)[36] and {PdCl(κ2-CN-
[37]
C12H12N)}2
were prepared according to published procedures.
All other reagents were purchased from commercial suppliers and
used directly without further purification.
1
(ratio 4.0:1) ppm. H NMR (CDCl3): δ = 8.80 (s, 1 H, arom. H),
7.85–6.81 (m, 17 H, arom. H), 5.07 (br., 1 H, NH), 4.95, 4.91 (both
Instrumentation: FT-IR spectra were recorded as KBr pellets over
the range 4000–200 cm–1 using a Perkin–Elmer system 2000 FT
spectrometer. 1H NMR and 31P{1H} NMR spectra (298Ϯ2 K)
s, 2 H, OCH2), 3.83, 2.99 (both br., 2 H, NCH2), 1.22 (d, 4J =
2 Hz, 15 H, Cp*) ppm. FT-IR (KBr): ν = 3282, 3242, 3226, 3211
˜
(NH), 1729 (CO), 1710 (amide I), 1514 (amide II) cm–1. ES-MS:
1074
www.eurjic.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 1068–1078

Flexible Ligation Behaviour of a Tridentate P/N/N Ligand
m/z = 795 [M – 2 Cl – H]. C38H40Cl2IrN2O3P (867.6): calcd. C
2 Cl – H]. C56H50Cl2N4O6P2Pt (1203.0): calcd. C 55.91, H 4.20, N
52.65, H 4.66, N 3.23; found C 52.82, H 4.85, N 2.88.
4.66; found C 55.84, H 3.82, N 4.48.
Rh(η5-Cp*)Cl2{2-Ph2PC6H4NHC(O)CH2NHCO2Bz} (4): The rho-
dium(III) complex was prepared from 2·HH and {RhCl2(η5-Cp*)}2
(89%). Selected data: 31P NMR (CDCl3): δ = 27.4 [J(RhP) =
Preparation of cis-Pd{2-Ph2PC6H4NC(O)CH2NHCO2Bz}2 (11):
tBuOK (0.035 g, 0.31 mmol) was added to a CH3OH (5 mL) sus-
pension of 8 (0.125 g, 0.112 mmol) to give a yellow solution fol-
143 Hz], 27.2 [J(RhP) = 143 Hz] (ratio 3.0:1.0) ppm. 1H NMR lowed by the immediate formation of a yellow solid. The mixture
(CDCl3): δ = 9.24 (s, 1 H, arom. H), 8.07–6.99 (m, 17 H, arom.
was refluxed for 3 h and left to cool overnight. The solid 11 was
collected by suction filtration, washed with a small portion of
CH3OH and dried. Yield 0.103 g, 88%. Selected data: 31P NMR
H), 5.22 (br., 1 H, NH), 5.10, 5.06 (both s, 2 H, OCH2), 3.88, 3.05
4
(both br., 2 H, NCH2), 1.40 (d, J = 3.6 Hz, 15 H, Cp*) ppm. FT-
IR (KBr): ν = 3237, 3194, (NH), 1726 (CO), 1706 (amide I), 1509 (CDCl3): δ = 42.2 ppm. 1H NMR (CDCl3): δ = 8.04 (m, 2 H,
˜
(amide II) cm–1. ES-MS: m/z
= 705 [M – 2 Cl – H]. arom. H), 7.43–6.91 (m, 36 H, arom. H), 5.73 (br., 2 H, NH), 5.08
C38H40Cl2N2O3PRh·0.5CH2Cl2 (820.0): calcd. C 56.39, H 5.05, N
3.42; found C 56.18, H 5.08, N 3.34.
(s, 4 H, OCH ), 4.33 (m, 4 H, NCH ) ppm. FT-IR (KBr): ν = 3377
˜
2 2
(NH), 1718 (CO and amide I), 1498 (amide II) cm–1. ES-MS: m/z
= 1131 [M – 2 Cl – H]. C56H48N4O6P2Pd (1041.4): calcd. C 64.59,
H 4.66, N 5.38; found C 63.78, H 4.68, N 5.24.
Preparation of Ru(η6-p-cymene)Cl2{2-Ph2PC6H4NHC(O)CH2-
NHCO2Bz} (6): 2·HH (0.098 g, 0.21 mmol) was added to a CH2Cl2
(10 mL) solution of {RuCl2(η6-p-cymene)}2 (0.064 g, 0.10 mmol). cis-Pt{2-Ph2PC6H4NC(O)CH2NHCO2Bz}2 (10): This complex was
The orange solution was stirred for 15 min and concentrated under
reduced pressure to ca. 1–2 mL. Addition of Et2O (10 mL) gave 6
which was collected by suction filtration and dried. Yield 0.146 g,
likewise prepared from 9 (88%). Selected data: 31P NMR (CDCl3):
δ = 19.7 [J(PtP) = 3217 Hz] ppm. FT-IR (KBr): ν = 3377 (NH),
˜
1718 (CO and amide I), 1498 (amide II) cm–1. ES-MS: m/z = 1130
90%. Selected data: 31P NMR (CDCl3): δ = 24.3, 23.7 (ratio [M+]. C56H48N4O6P2Pt (1130.1): calcd. C 59.52, H 4.29, N 4.96;
1
5.5:1.0) ppm. H NMR (CDCl3): δ = 8.89 (s, 1 H, arom. H), 8.01
(m), 7.88–7.08 (m), 5.30–4.89 (m, p-cymene, OCH2, NCH2), 2.89
(sept., 1 H, CH), 1.87 (s, 3 H, CH3), 1.24 [br, 6 H, CH(CH3)2] ppm.
found C 59.08, H 3.96, N 4.77.
Preparation of cis-Ni{2-Ph2PC6H4NC(O)CH2NHCO2Bz}2 (12): A
mixture of NiCl2·6H2O (0.025 g, 0.11 mmol), 2·HH (0.103 g,
0.220 mmol) and tBuOK (0.035 g, 0.32 mmol) in CH3OH (10 mL)
was refluxed for 3 h. The mixture was left to stand to deposit an
orange crystalline material that was collected by filtration under
suction and dried. Yield 0.022 g, 21%. Selected data: 31P NMR
FT-IR (KBr): ν = 3365, 3237, 3208 (NH), 1730 (CO), 1704 (amide
˜
I), 1522 (amide II) cm–1. ES-MS: m/z = 775 [M]. C38H39Cl2N2O3-
PRu (774.7): calcd. C 58.91, H 5.08, N 3.62; found C 58.76, H 4.94,
N 3.51.
Preparation of Pd(κ2-CN-C12H12N)Cl{2-Ph2PC6H4NHC(O)CH2- (CDCl ): δ = 21.2 ppm. FT-IR (KBr): ν = 3377, 3245 (NH), 1714
˜
3
NHCO2Bz} (7): 2·HH (0.121 g, 0.258 mmol) was added to a (CO and amide I) cm–1. ES-MS: m/z = 993 [M]. C56H48N4NiO6P2
CH2Cl2 (20 mL) solution of {PdCl(κ2-CN-C12H12N)}2 (0.079 g,
0.13 mmol). The yellow solution was stirred for 30 min and concen-
trated under reduced pressure to ca. 1–2 mL. Addition of Et2O
(10 mL) and petroleum ether (b.p. 60–80 °C, 20 mL) gave 7 which
was collected by suction filtration and dried. Yield 0.134 g, 68%.
Selected data: 31P NMR (CDCl3): δ = 38.8 ppm. 1H NMR
(CDCl3): δ = 9.17 (s, 1 H, arom. H), 7.83–6.81 (m, 23 H, arom.
H), 6.61 (t, 1 H, arom. H), 6.45 (t, 1 H, arom. H), 5.21 (br., 1 H,
NH), 4.94 (s, 2 H, OCH2), 3.54 (d, J = 2.8 Hz, 2 H, NCH2), 3.42
(993.7): calcd. C 67.70, H 4.88, N 5.64; found C 67.74, H 4.84, N
5.37.
Preparation of Ir(η5-Cp*){2-Ph2PC6H4NC(O)CH2NCO2Bz} (14):
A mixture of 5 (0.029 g, 0.033 mmol) and tBuOK in CH3OH
(5 mL) was refluxed, under nitrogen for 3 h. The solution was co-
oled and the solvents evaporated to dryness under reduced pres-
sure. Examination of the crude mixture revealed two new major
species at δ(P) = 16.0 and 8.0 ppm in a 1:3.2 ratio. Crystallisation
was achieved using CDCl3/petroleum ether (b.p. 60–80 °C) to give
a small quantity of crystalline material identified as 14. Selected
data: 31P NMR (C6D6): δ = 17.7, 8.8 (ratio 1.4:1.0) ppm. 1H NMR
(C6D6): δ = 8.66 (dd, 1 H, arom. H), 8.60 (dd, 1 H, arom. H), 8.03
(m, 1 H, arom. H), 7.80 (m, 1 H, arom. H), 7.63–6.72 (m, 34 H,
arom. H), 5.64 (d, J = 17.6 Hz, 1 H, CH2), 5.44 (dd, 2 H, CH2),
5.09 (d, J = 11.6 Hz, 1 H, CH2), 4.96 (d, J = 17.6 Hz, 1 H, CH2),
4.87 (d, J = 11.2 Hz, 1 H, CH2), 4.44 (d, J = 17.6 Hz, 1 H, CH2),
4.28 (d, J = 17.2 Hz, 1 H, CH2), 1.30 (d, J = 2.4 Hz, 15 H, Cp*),
(s, 6 H, CH ) ppm. FT-IR (KBr): ν = 3420, 3297 (NH), 1725 (CO),
˜
3
1691 (amide I), 1498 (amide II) cm–1. ES-MS: m/z = 745 [M – Cl].
C40H37ClN3O3PPd (780.6): calcd. C 61.54, H 4.79, N 5.38; found
C 61.64, H 4.38, N 5.05.
Preparation of PdCl2{2-Ph2PC6H4NHC(O)CH2NHCO2Bz}2 (8):
2·HH (0.226 g, 0.482 mmol) was added to a CH2Cl2 (20 mL) solu-
tion of PdCl2(cod) (0.069 g, 0.24 mmol). The yellow solution was
stirred for ca. 1 h and concentrated under reduced pressure to ca.
1–2 mL. Addition of Et2O (10 mL) and hexanes (10 mL) gave 8
which was collected by suction filtration and dried. Yield 0.260 g,
97%. Selected data: 31P NMR (CDCl3): δ = 19.9, 19.1 ppm. 1H
1.08 (d, J = 2.0 Hz, 15 H, Cp*) ppm. FT-IR (KBr): ν = 1658, 1626
˜
(CO and amide I) cm–1. ES-MS: m/z = 795 [M + H]+. C37H38Ir-
N2O3P (781.9): calcd. C 56.83, H 4.91, N 3.58; found C 56.69, H
NMR (CDCl3): δ = 8.43 (s, 2 H, arom. H), 7.75–7.06 (m, 38 H, 4.71, N 3.45.
arom. H), 5.24 (br., 2 H, NH), 5.03 (s, 4 H, OCH2), 3.35 (br., 4 H,
Preparation of Ru(η6-p-cymene){2-Ph2PC6H4NC(O)CH2NCO2Bz}
NCH ) ppm. FT-IR (KBr): ν = 3312 (NH), 1724 (CO), 1700
˜
2
(15): A mixture of 6 (0.071 g, 0.092 mmol) and tBuOK (0.027 g,
0.24 mmol) in CH3OH (10 mL) was stirred at room temperature
for ca. 4 h then refluxed, under nitrogen for 2 h. The solution was
cooled and the solvents evaporated to dryness under reduced pres-
sure. The crude material was taken up in CH2Cl2 (10 mL) and
passed through a Celite plug. The volume was concentrated under
(amide I), 1506 (amide II) cm–1. ES-MS: m/z = 1041 [M – 2 Cl –
H]. C56H50Cl2N4O6P2Pd (1114.3): calcd. C 60.36, H 4.53, N 5.03;
found C 60.25, H 4.17, N 4.77.
PtCl2{2-Ph2PC6H4NHC(O)CH2NHCO2Bz}2 (9): This compoound
was prepared from PtCl2(cod) and two equiv. of 2·HH (91%). Se-
lected data: 31P NMR (CDCl3): δ = 6.7 [J(PtP) = 3657 Hz] (major reduced pressure to 1–2 mL and diethyl ether (10 mL)/hexanes
species) ppm. 1H NMR (CDCl3): δ = 9.23 (s, 2 H, arom. H), 7.78–
(10 mL) added. The precipitate was left to stand overnight, filtered
6.77 (m, 38 H, arom. H), 5.60 (br., 2 H, NH), 5.10 (s, 4 H, OCH2), and dried in vacuo to give 15. Yield 0.051 g, 80%. Selected data:
3.79 (br., 4 H, NCH ) ppm. FT-IR (KBr): ν = 3377 (NH), 1718
31P NMR (CDCl3): δ = 50.2, 46.6 (ratio 1.0:1.0) ppm. 1H NMR
(CDCl3): δ = 7.73 (dd, 1 H, arom. H), 7.65 (dd, 1 H, arom. H),
˜
2
(CO and amide I), 1498 (amide II) cm–1. ES-MS: m/z = 1131 [M –
Eur. J. Inorg. Chem. 2009, 1068–1078
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1075

M. R. J. Elsegood, A. J. Lake, M. B. Smith
FULL PAPER
7.44–6.97 (m, 34 H, arom. H), 6.85 (t, 1 H, arom. H), 6.78 (t, 1 H, evaporation to dryness of a CH2Cl2/Et2O filtrate from the reaction
arom. H), 5.16–4.66 (m, 12 H, p-cymene, CH2), 3.97 (d, 1 H, CH2), of [PtCl2(cod)]/1 equiv. 2·HH (for 13·Et2O) or CDCl3/Et2O solu-
3.80 (d, 1 H, CH2), 3.72 (dd, 2 H, CH2), 2.38 (sept., 1 H, CH), tion (for 2·HH) afforded suitable X-ray quality crystals. A warm
2.06 (sept., 1 H, CH), 1.79 (s, 3 H, CH3), 1.47 (s, 3 H, CH3), 0.98 solution of NiCl2·6H2O, 2·HH and tBuOK in CH3OH was cooled
[d, J = 6.8 Hz, 3 H, CH(CH3)2], 0.91 [d, J = 6.8 Hz, 3 H, CH- over 2 d to give suitable crystals of 12. Measurements were made
(CH3)2], 0.77 [dd, J = 6.8 Hz, 6 H, CH(CH3)2] ppm. FT-IR (KBr):
˜
C38H37N2O3PRu·H2O (720.7): calcd. C 63.32, H 5.47, N 3.89;
found C 62.97, H 4.96, N 3.71.
with either a Bruker AXS SMART 1000 CCD area-detector dif-
fractometer[38] for 2·HH, 2a, 4·Et2O, 10–12, 13·Et2O and 14 using
sealed-tube graphite-monochromated Mo-Kα radiation and narrow
frame exposures (0.3°) in ω or a Bruker-Nonius 95-mm CCD
kappa diffractometer[39,40] equipped with a rotating-anode genera-
tor for 3 and 8. Cell parameters were refined from the observed
(ω) angles of all strong reflections in each data set. Intensities were
corrected semiempirically for absorption, based on symmetry-
equivalent and repeated reflections. The structures were solved by
ν = 1647, 1619 (CO and amide I) cm–1. EI-MS: m/z = 702 [M]+.
X-ray Crystallography: Suitable crystals were grown by vapour dif-
fusion of diethyl ether into either a CH2Cl2 (for 4·Et2O, 10, 11) or
CDCl3 (for 2a, 3, 8) solution. Crystals of 14 were obtained by layer-
ing petroleum ether (b.p. 60–80 °C) over a CDCl3 solution. Slow
Table 5. Crystallographic data for 2·HH, 2a, 3, 4·Et2O and 8.
Compound
2·HH
2a
3
4·Et2O
8
Empirical formula
Formula weight
Crystal system
Space group
a [Å]
b [Å]
c [Å]
C28H25N2O3P
468.47
orthorhombic
Pbca
9.7453(6)
17.9907(11)
26.6542(17)
C28H25N2O4P
484.47
C28H25AuClN2O3P
700.89
monoclinic
C2/c
22.952(5)
12.739(3)
17.885(4)
C42H50Cl2N2O4PRh
851.62
orthorhombic
P212121
8.4053(3)
17.2229(7)
C56H50Cl2N4O6P2Pd
1114.24
triclinic
triclinic
¯
¯
P1
P1
10.0621(5)
13.8305(6)
18.7642(9)
95.1715(8)
93.9950(8)
110.7979(8)
2416.7(2)
4
9.8211(2)
12.3556(3)
13.4933(3)
73.3569(15)
69.6192(15)
68.1251(11)
1401.06(5)
1
28.0623(12)
α [°]
β [°]
γ [°]
94.44(3)
Volume [Å3]
Z
4673.1(5)
8
5213.6(18)
8
4062.4(3)
4
T [K]
150(2)
150(2)
1.332
0.152
120(2)
1.786
5.840
150(2)
1.392
0.634
120(2)
1.321
0.534
Density (calcd.) [Mg/m3] 1.332
Absorption coeff. [mm–1] 0.151
Crystal
plate, colourless
block, colourless
0.52ϫ0.32ϫ0.14
1.59–29.16
21740
block, colourless
0.28ϫ0.14ϫ0.06
2.98–27.49
26325
block, orange
0.56ϫ0.32ϫ0.13
1.45–28.99
35012
plate, yellow
0.28ϫ0.10ϫ0.04
3.18–27.50
29162
Crystal size [mm3]
θ Range [°]
0.71ϫ0.10ϫ0.06
2.26–29.05
38962
Reflections collected
Independent reflections 5816
[Rint = 0.0578]
0.0452, 0.1049
11284
[Rint = 0.0172]
0.0392, 0.0992
5958
[Rint = 0.0566]
0.0281, 0.0637
9701
[Rint = 0.0404]
0.0775, 0.1800
6423
[Rint = 0.1545]
0.0589, 0.1593
Final R, Rw
Table 6. Crystallographic data for 10–12, 13·Et2O and 14.
Compound
10
11
12
13·Et2O
14
Empirical formula
Formula weight
Crystal system
Space group
a [Å]
b [Å]
c [Å]
C56H48N4O6P2Pt
1130.01
C56H48N4O6P2Pd
1041.32
C56H48N4NiO6P2
993.63
C60H59ClN4O7P2Pt
1240.59
C38H38IrN2O3P
793.87
orthorhombic
Pbca
14.5434(6)
19.0261(9)
24.0410(11)
triclinic
triclinic
triclinic
triclinic
¯
¯
¯
¯
P1
P1
P1
P1
10.9838(5)
12.0189(6)
18.9373(9)
86.5717(8)
75.4249(7)
89.6824(8)
2415.1(2)
2
10.9942(6)
12.0245(6)
18.9440(10)
86.3778(9)
75.5354(9)
89.6384(9)
2420.0(2)
2
10.8720(6)
12.0122(6)
18.9051(10)
84.0006(10)
75.6778(9)
89.4411(9)
2378.8(2)
2
13.0842(5)
18.0484(7)
25.0130(9)
109.3285(6)
91.6609(6)
98.6980(6)
5489.9(4)
4
α [°]
β [°]
γ [°]
Volume [Å3]
Z
6652.2(5)
8
T [K]
150(2)
150(2)
1.429
0.506
150(2)
1.387
0.533
150(2)
1.501
2.720
150(2)
1.585
4.102
Density (calcd.) [Mg/m3] 1.554
Absorption coeff. [mm–1] 3.028
Crystal
block, colourless
block, yellow
0.43ϫ0.34ϫ0.16
1.70–29.00
21527
block, orange
0.28ϫ0.16ϫ0.07
1.70–29.08
21340
block, colourless
0.42ϫ0.34ϫ0.11
1.23–25.00
40463
block, yellow
0.23ϫ0.22ϫ0.15
1.69–25.00
45915
Crystal size [mm3]
θ Range [°]
0.35ϫ0.16ϫ0.13
1.70–29.02
21653
Reflections collected
Independent reflections
11226
11181
11032
19293
5877
[Rint = 0.0255]
0.0300, 0.0585
[Rint = 0.0216]
0.0338, 0.0783
[Rint = 0.0324]
0.0457, 0.1083
[Rint = 0.0269]
0.0302, 0.0677
[Rint = 0.0470]
0.0471, 0.1307
[a]
Final R, Rw
[a] R = Σ||Fo| – |Fc||/Σ|Fo| for “observed” reflections having F2 Ͼ 2σ (F2). Rw = [Σw(Fo – Fc ) /Σw(Fo2)2]1/2 for all data.
2
2 2
1076 Eur. J. Inorg. Chem. 2009, 1068–1078
www.eurjic.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Flexible Ligation Behaviour of a Tridentate P/N/N Ligand
2425; d) A. Del Zotto, W. Baratta, M. Ballico, E. Herdtweek,
P. Rigo, Organometallics 2007, 26, 5636–5642; e) M. L. Clarke,
M. B. Díaz-Valenzuela, A. M. Z. Slawin, Organometallics 2007,
26, 16–19; f) J. Zhang, M. Gandelman, L. J. W. Shimon, D.
Milstein, Dalton Trans. 2007, 107–113; g) C. E. Anderson,
D. C. Apperley, A. S. Batsanov, P. W. Dyer, J. A. K. Howard,
Dalton Trans. 2006, 4134; h) J. Hou, W.-H. Sun, S. Zhang, H.
Ma, Y. Deng, X. Lu, Organometallics 2006, 25, 236–244; i) L.
Boubekeur, S. Ulmer, L. Ricard, N. Mézailles, P. Le Floch, Or-
ganometallics 2006, 25, 315–317.
a) S. R. Bayly, A. R. Cowley, J. R. Dilworth, C. V. Ward, Dal-
ton Trans. 2008, 2190–2198; b) P. Pelagatti, A. Bacchi, M. Ba-
lordi, S. Bolaño, F. Calbiani, L. Elviri, L. Gonsalvi, C. Pelizzi,
M. Peruzzini, D. Rogolino, Eur. J. Inorg. Chem. 2006, 2422–
2436; c) O. M. Ní Dhubhghaill, J. Lennon, M. G. B. Drew, Dal-
ton Trans. 2005, 3213–3220; d) S. R. Korupoju, R.-Y. Lai, Y.-
H. Liu, S.-M. Peng, S.-T. Liu, Inorg. Chim. Acta 2005, 358,
3003–3008; e) N. Nimitsiriwat, E. L. Marshall, V. C. Gibson,
M. R. J. Elsegood, S. H. Dale, J. Am. Chem. Soc. 2004, 126,
13598–13599; f) W.-Q. Hu, X.-L. Sun, C. Wang, Y. Gao, Y.
Tang, L.-P. Shi, W. Xia, J. Sun, H.-L. Dai, X.-Q. Li, X.-L. Yao,
X.-R. Wang, Organometallics 2004, 23, 1684–1688; g) P.-Y. Shi,
Y.-H. Liu, S.-M. Peng, S.-T. Liu, Organometallics 2002, 21,
3203–3207; h) M. Ahmad, S. D. Perera, B. L. Shaw, M. Thorn-
ton-Pett, J. Chem. Soc., Dalton Trans. 2002, 1954–1962; i) P.
Pelagatti, A. Bacchi, C. Bobbio, M. Carcelli, M. Costa, C. Pel-
izzi, C. Vivorio, Organometallics 2000, 19, 5440–5446; j) P.
Bhattacharyya, J. Parr, A. M. Z. Slawin, J. Chem. Soc., Dalton
Trans. 1998, 3609–3614; k) E. K. van den Beuken, N. Veldman,
W. J. J. Smeets, A. L. Spek, B. L. Feringa, Organometallics
1998, 17, 636–644.
direct methods (Patterson synthesis for 10 and 11) and refined on
F2 values for all unique data by full-matrix least-squares.[41] Table 5
and Table 6 give further details. All non-hydrogen atoms were re-
fined anisotropically. For 14 the C(11) Ͼ C(16) ring is common to
both disorder components and there are two possible conforma-
tions of the linkage between this ring and N(2): 56.0(11)% of the
time via C(9), O(3), C(10) and 44.0(11)% of the time via C(9X),
O(3X), C(10X). For compound 4·Et2O a molecule of badly disor-
derd Et2O was modelled by the Platon Squeeze procedure.[42] The
X-ray structures of 11 (Figure S1) and 12 (Figure S2), with full
atom numbering schemes, are given in the Supporting Information.
[14]
CCDC-706564 (for 2·HH), -706565 (for 2a), -706566 (for 3),
-706567 (for 4·Et2O), -706568 (for 8), -706569 (for 10), -706570 (for
11), -706571 (for 12), -706572 (for 13·Et2O) and -706573 (for 14)
contain the complete set of X-ray crystallographic structural data.
These can be obtained free of charge from The Cambridge Crystal-
lographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Supporting Information (see also the footnote on the first page of
this article): Four figures showing additional crystal structures,
packing plots, and full atom numbering.
Acknowledgments
We should like to thank the Engineering and Physical Sciences Re-
search Council (EPSRC) X-ray Service at Southampton University
for collecting the data set for compounds 3 and 8, Johnson Matthey
for the generous loan of precious metal salts and the EPSRC Mass
Spectrometry Service Centre at Swansea. We also acknowledge the
Engineering and Physical Sciences Research Council (EPSRC) for
partial funding (A. J. L.).
[15]
[16]
a) T. Kniess, C. Fernandes, I. Santos, W. Kraus, H. Spies, Inorg.
Chim. Acta 2003, 348, 237–241; b) J. D. G. Correia, A. Domin-
gos, I. Santos, H. Spies, J. Chem. Soc., Dalton Trans. 2001,
2245–2250.
a) C. Gunanathan, D. Milstein, Angew. Chem. Int. Ed. 2008,
47, 8661–8664; b) L.-C. Liang, P.-S. Chien, P.-Y. Lee, Organo-
metallics 2008, 27, 3082–3093; c) D. Adhikari, F. Basuli, H.
Fan, J. C. Huffman, M. Pink, D. J. Mindiola, Inorg. Chem.
2008, 47, 4439–4441; d) J. I. van der Vlugt, E. A. Pidko, D.
Vogt, M. Lutz, A. L. Spek, A. Meetsma, Inorg. Chem. 2008,
47, 4442–4444; e) D. Benito-Garagorri, J. Wiedermann, M.
Pollak, K. Mereiter, K. Kirchner, Organometallics 2007, 26,
217–222; f) C. M. Fafard, C.-H. Chen, B. M. Foxman, O. V.
Ozerov, Chem. Commun. 2007, 4465–4467; g) A. R. Fout, F.
Basuli, H. Fan, J. Tomaszewski, J. C. Huffman, M.-H. Baik,
D. J. Mindiola, Angew. Chem. Int. Ed. 2006, 45, 3291–3295; h)
E. Ben-Ari, G. Leitus, L. J. W. Shimon, D. Milstein, J. Am.
Chem. Soc. 2006, 128, 15390–15391; i) D. S. McGuiness, D. B.
Brown, R. P. Tooze, F. M. Hess, J. T. Dixon, A. M. Z. Slawin,
Organometallics 2006, 25, 3605–3610; j) D. Benito-Garagorri,
E. Becker, J. Wiedermann, W. Lackner, M. Pollak, K. Mereiter,
J. Kisala, K. Kirchner, Organometallics 2006, 25, 1900–1913;
k) B. C. Bailey, H. Fan, J. C. Huffman, M.-H. Baik, D. J. Min-
diola, J. Am. Chem. Soc. 2006, 128, 6798–6799; l) S. M. Kloek,
D. M. Heinekey, K. I. Goldberg, Organometallics 2006, 25,
3007–3011; m) M. Porchia, F. Tisato, F. Refosco, C. Bolzati,
M. Cavazza-Ceccato, G. Bandoli, A. Dolmella, Inorg. Chem.
2005, 44, 4766–4776; n) L. Fan, B. M. Foxman, O. V. Ozerov,
Organometallics 2004, 23, 326–328; o) M. S. Rahman, P. D.
Prince, J. W. Steed, K. K. Hii, Organometallics 2002, 21, 4927–
4933.
[1] S. Sen, P. Talukder, S. K. Dey, S. Mitra, G. Rosair, D. L.
Hughes, G. P. A. Yap, G. Pilet, V. Gramlich, T. Matsushita,
Dalton Trans. 2006, 1758–1767.
[2] S. Akine, A. Akimoto, T. Shiga, H. Oshio, T. Nabeshima, In-
org. Chem. 2008, 47, 875–885.
[3] S. Nag, P. Gupta, R. J. Butcher, S. Bhattacharya, Inorg. Chem.
2004, 43, 4814–4816.
[4] J. E. Reed, A. Arola Arnal, S. Neidle, R. Vilar, J. Am. Chem.
Soc. 2006, 128, 5992–5993.
[5] M. E. Germain, M. J. Knapp, J. Am. Chem. Soc. 2008, 130,
5422–5423.
[6] Y.-C. Chou, S.-F. Huang, R. Koner, G.-H. Lee, Y. Wang, S.
Mohanta, H.-H. Wei, Inorg. Chem. 2004, 43, 2759–2761.
[7] Q.-Z. Yang, L.-Z. Wu, H. Zhang, B. Chen, Z.-X. Wu, L.-P.
Zhang, C.-H. Tung, Inorg. Chem. 2004, 43, 5195–5197.
[8] C. S. Consorti, G. Ebeling, F. Rodembusch, V. Stefani, P. R.
Livotto, F. Rominger, F. H. Quina, C. Yihwa, J. Dupont, Inorg.
Chem. 2004, 43, 530–536.
[9] H. Jude, J. A. Krause Bauer, W. B. Connick, Inorg. Chem. 2004,
43, 725–733.
[10] a) M. L. Grachan, M. T. Tidge, E. N. Jacobsen, Angew. Chem.
Int. Ed. 2008, 47, 1469–1472; b) J. Lewin´ski, P. Horeglad, M.
Dranka, I. Justyniak, Inorg. Chem. 2004, 43, 5789–5791.
[11] A. D. Getty, K. I. Goldberg, Organometallics 2001, 20, 2545–
2551.
[12] a) T. Hara, T. Yamagata, K. Mashima, Y. Kataoka, Organome-
tallics 2007, 26, 110–118; b) J.-F. Gong, Y.-H. Zhang, M.-P.
Song, C. Xu, Organometallics 2007, 26, 6487–6492; c) Y. Ka-
taoka, K. Shizuma, M. Imanishi, T. Yamagata, K. Tani, J. Or-
ganomet. Chem. 2004, 689, 3–7.
[13] a) F.-B. Han, Y.-L. Zhang, X.-L. Sun, B.-G. Li, Y.-H. Guo, Y.
Tang, Organometallics 2008, 27, 1924–1928; b) J. A. Fuentes,
M. L. Clarke, A. M. Z. Slawin, New J. Chem. 2008, 32, 689–
693; c) Z.-X. Wang, L. Wang, Chem. Commun. 2007, 2423–
[17]
[18]
S. E. Durran, M. R. J. Elsegood, M. B. Smith, New J. Chem.
2002, 26, 1402–1408.
For selected recent examples: a) V. Pandarus, D. Zargarian,
Chem. Commun. 2007, 978–980; b) R. B. Bedford, M. Betham,
J. P. H. Charmant, M. F. Haddow, A. G. Orpen, L. T. Pilarski,
S. J. Coles, M. B. Hursthouse, Organometallics 2007, 26, 6346–
6353; c) L. Ma, R. A. Woloszynek, W. Chen, T. Ren, J. D. Pro-
tasiewicz, Organometallics 2006, 25, 3301–3304.
Eur. J. Inorg. Chem. 2009, 1068–1078
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1077

M. R. J. Elsegood, A. J. Lake, M. B. Smith
FULL PAPER
[19] E. E. Korshin, G. Leitus, L. J. W. Shimon, L. Konstantinovski,
D. Milstein, Inorg. Chem. 2008, 47, 7177–7189.
[31] a) M. B. Smith, A. M. Z. Slawin, New J. Chem. 2000, 24, 65–
67; b) A. M. Z. Slawin, M. B. Smith, New J. Chem. 1999, 23,
777–783.
[32] Y. Yamamoto, X.-H. Han, S. Nishimura, K.-i. Sugawara, N.
Nezu, T. Tanase, Organometallics 2001, 20, 266–272.
[33] R. Uson, A. Laguna, M. Laguna, Inorg. Synth. 1989, 26, 85–
91.
[34] a) D. Drew, J. R. Doyle, Inorg. Synth. 1972, 13, 47–55; b) J. X.
McDermott, J. F. White, G. M. Whitesides, J. Am. Chem. Soc.
1976, 98, 6521–6528.
[20] a) X. Sun, D. W. Johnson, K. N. Raymond, E. H. Wong, Inorg.
Chem. 2001, 40, 4504–4506; b) X. Sun, D. W. Johnson, D. L.
Caulder, K. N. Raymond, E. H. Wong, J. Am. Chem. Soc.
2001, 123, 2752–2763; c) X. Sun, D. W. Johnson, D. L. Caulder,
R. E. Powers, K. N. Raymond, E. H. Wong, Angew. Chem. Int.
Ed. 1999, 38, 1303–1307.
[21] M. R. J. Elsegood, M. B. Smith, P. M. Staniland, Inorg. Chem.
2006, 45, 6761–6770.
[22] I. D. Kostas, B. R. Steele, A. Terzis, S. V. Amosova, A. V. Mar-
tynov, N. A. Makhaeva, Eur. J. Inorg. Chem. 2006, 2642–2646.
[23] a) Q. Yao, M. Sheets, J. Org. Chem. 2006, 71, 5384–5387; b)
V. J. Olsson, S. Sebelius, N. Selander, K. J. Szabo, J. Am. Chem.
Soc. 2006, 128, 4588–4589.
[24] J. H. Downing, M. B. Smith, Phosphorus Ligands in Compre-
hensive Coordination Chemistry II, Elsevier, Oxford, 2004, 253–
296.
[25] S. E. Durran, M. R. J. Elsegood, S. R. Hammond, M. B.
Smith, Inorg. Chem. 2007, 46, 2755–2766.
[26] M. Oswaw, M. Hoshino, M. Akita, T. Wada, Inorg. Chem.
2005, 44, 1157–1159.
[27] S. C. F. Kui, J.-S. Huang, R. W.-Y. Sun, N. Zhu, C.-M. Che,
Angew. Chem. Int. Ed. 2006, 45, 4663–4666.
[28] M. B. Smith, S. H. Dale, S. J. Coles, T. Gelbrich, M. B. Hurst-
house, M. E. Light, CrystEngComm 2006, 8, 140–149.
[29] H. Schmidbaur, A. Schier, Chem. Soc. Rev. 2008, 37, 1931–
1951.
[35] M. A. Bennett, A. K. Smith, J. Chem. Soc., Dalton Trans. 1974,
233–241.
[36] C. White, A. Yates, P. M. Maitlis, Inorg. Synth. 1992, 29, 228–
234.
[37] a) A. C. Cope, E. C. Friedrich, J. Am. Chem. Soc. 1968, 90,
909–913; b) A. C. Cope, R. W. Siekman, J. Am. Chem. Soc.
1965, 87, 3272–3273.
[38] SMART and SAINT software for CCD diffractometers,
Bruker AXS Inc., Madison, WI, 2001.
[39] COLLECT: Data Collection Software, R. Hooft, Nonius B. V.,
1998.
[40] DENZO, Z. Otwinowski, W. Minor, in: C. W. Carter Jr., R. M.
Sweet (Eds.), Methods in Enzymology, Macromolecular Crystal-
lography, part A, vol. 276, Academic Press, 1997, 307–326.
[41] a) G. M. Sheldrick, SHELXTL user manual, version 6.10,
Bruker ACS Inc., Madison, WI, 2000; b) G. M. Sheldrick, Acta
Crystallogr., Sect. A 2008, 64, 112.
[42] A. L. Spek, Acta Crystallogr., Sect. A 1990, 46, C34.
[30] S. Chikkali, S. Magens, D. Gudat, M. Nieger, I. Hartenbach,
T. Schleid, Eur. J. Inorg. Chem. 2008, 2207–2213.
Received: November 12, 2008
Published Online: February 6, 2009
1078
www.eurjic.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2009, 1068–1078