Synthesis and coordination of 2-diphenylphosphinothiophenocarboxamide and bis(2,5-diphenylphosphinepicolinamide)

Article abstract of DOI:10.1016/j.poly.2004.09.014

2-Diphenylphosphinothiophenocarboxamide (dpptc) and bis(2,5- diphenylphosphinepicolinamide) (bdpppa) have been prepared and complexed with a variety of metals. Bdpptc behaves as a monodentate P donor ligand and can become bidentate by making use of the CO site. Bdpppa behaves as a P donor bridging ligand. In many cases, the X-ray structures reveal that the ligand backbone geometry is strongly influenced by intramolecular H-bonding.

Full text of DOI:10.1016/j.poly.2004.09.014

Polyhedron 23 (2004) 2575–2585
www.elsevier.com/locate/poly
Synthesis and coordination of 2-diphenylphosphinothio-
phenocarboxamide and bis(2,5-diphenylphosphinepicolinamide)
*
Heather L. Milton, Matthew V. Wheatley, Alexandra M.Z. Slawin, J. Derek Woollins
School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9NB, UK
Received 29 June 2004; accepted 20 September 2004
Abstract
2-Diphenylphosphinothiophenocarboxamide (dpptc) and bis(2,5-diphenylphosphinepicolinamide) (bdpppa) have been prepared
and complexed with a variety of metals. Bdpptc behaves as a monodentate P donor ligand and can become bidentate by making use
of the C@O site. Bdpppa behaves as a P donor bridging ligand. In many cases, the X-ray structures reveal that the ligand backbone
geometry is strongly influenced by intramolecular H-bonding.
Ó 2004 Elsevier Ltd. All rights reserved.
Keywords: Phosphine; Synthesis; Coordination; X-ray structure
1. Introduction
There are few known examples of phosphino-thio-
phenes, and even fewer that act as bidentate phosph-
ino-thiophene ligands. Clot et al. described the major
examples in 2000 [3]; 2-(20-{diphenylphosphino}phe-
nyl)thiophene (dpppth) (A) and 30-diphenylphosphino-
2,20:50,200-terthiophene (dppterth) (B).
Hemilabile phosphorus–nitrogen ligands are of great
interest and we have recently described the synthesis and
coordination
(dpppa) and other P–N-based ligands [1,2].
of
2-diphenylphosphinopicolinamide
PPh2
O
PPh2
S
S
S
PPh2
N
S
H
N
A
B
dpppa
These ligands were both shown to bind with a biden-
tate motif on reaction with [RuCl2(PPh3)3].
Early bridging diphosphines include 2,6-bis(diph-
enylphosphino)pyridine ((Ph2P)2py) (C), 2,6-(diphenyl-
phosphinomethyl)pyridine (D) and N,N0-bis(diph-
enylphosphino)-2,6-diaminopyridine (E) [4]. These
ligands are commonly found as bridging ligands and
bidentate ligands with a variety of transition metals.
*
Corresponding author. Tel.: +44 133 446 3869; fax: +44 133 446
3384.
E-mail address: jdw3@st-andrews.ac.uk (J.D. Woollins).
0277-5387/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2004.09.014

2576
H.L. Milton et al. / Polyhedron 23 (2004) 2575–2585
Ph2P
N
PPh2
C
H
H
N
N
N
N
PPh2
PPh2
PPh2
PPh2
D
E
Here, we describe two new hemilabile ligands: 2-diph-
enylphosphinothiophenocarboxamide (dpptc) and
bis(2,5-diphenylphosphinepicolinamide) (bdpppa). The
coordination properties are compared with dpppa.
2. Results and discussion
˚
Fig. 1. Crystal structure of dpptc-O, 2, selected bond lengths (A) and
The synthesis of dpptc (1) is analogous to that of
dpppa (Eq. (1)).
angles (°): P(1)–O(1) 1.456(3), P(1)–N(2) 1.692(3), O(3)–C(3) 1.229(4),
N(2)–C(3) 1.373(5), C(3)–C(4) 1.463(5), S(5)–C(4) 1.725(4), C(4)–C(8)
1.365(5), N(2)–O(1) 2.80, N(2)–P(1)–O(1) 115.10(16), C(17)–P(1)–O(1)
112.61(16), N(2)–H(2)ꢁ ꢁ ꢁO(1) 171.
H
Ph2PCl, Et3N
NH2
N
S
S
PPh2
Reflux, THF
ð1Þ
O
O
displays the anticipated changes from the free ligand.
The amine proton is shifted to d(H) 9.7 ppm, also the
coupling constant has increased to JP–H = 11 Hz. The
1
2
The ligand is readily soluble in chlorinated solvents,
acetone, tetrahydrofuran, somewhat less so in toluene,
methanol and diethylether. A singlet is observed in the
31P spectrum of dpptc at d(P) 25.9 ppm; comparable
m(N–H) vibration in the IR spectrum has shifted to a
lower wave number (3214 cmꢀ1), suggesting the possibil-
ity of intermolecular hydrogen bonding interactions
within the complex. The m(C@O) also shifts considerably
to 1672 cmꢀ1 Two Pt-Cl stretches are visible in the spec-
trum (304 and 273 cmꢀ1), another indication of a cis-
conformation in 4.
Reaction of dpptc with [{Pd(l-Cl)(g3-C3H5)}2] gives
the expected monodentate dpptc complex [PdCl(g3-
C3H5)(dpptc-P)] (5), d(P) 54.3 ppm. The X-ray structure
of 5 (Fig. 2) confirms the P coordination and displays
1
with the value for dpppa. The H NMR spectrum does
not show the presence of an amide proton, as this reso-
nance is obscured by the main body of the aromatic pro-
tons. The IR spectra shows the expected peaks, a weak
m(N–H) band is present at 3265 cmꢀ1 together with
bands attributable to m(thCS) and m(P–N) at 1096 and
996 cmꢀ1 respectively, with m(C–N) coming at 1522
cmꢀ1. The expected m(C@O) signature is visible at
˚
hydrogen bonding, [N(7)–H(7)ꢁ ꢁ ꢁCl(1) 3.166 A, with a
1624 cmꢀ1
.
N(7)–H(7)ꢁ ꢁ ꢁCl(1) 131°], there is no evidence of sulfur
Only the sulfide of dpptc was synthesised (by reaction
of dpptc with elemental sulfur in toluene, dpptc-S (3), d(P)
57.2 ppm) as a representative example of the P(V) form.
However, a crystal of the oxide derivative was obtained
via air oxidation of the free ligand in a CDCl3 solution
(Fig. 1). In the solid state, the molecules adopt a chain line
structure as a consequence of hydrogen bonding.
coordination.
The mixed phosphine complex [PtCl2(PPhMe2)-
(dpptc-P)] (6) was synthesised from [{PtCl(l-Cl)-
(PPhMe2)}2] and dpptc in dichloromethane. The 31P
NMR of 6 showed two doublets with the appropriate
2
platinum satellites [d(P) 29.7 ppm, JP–P = 18.8 Hz,
2
1JPt–P = 3890 Hz, d(P) ꢀ15.6 ppm, JP–P = 18.8 Hz,
Dpptc reacts with [PtCl2(cod)] in dichloromethane to
give cis-[PtCl2(dpptc-P)2] (4), no trans-bis(dpptc) or
mono-(dpptc) binding was observed. The 31P NMR of
4 is a singlet at d(P) 27.9 ppm with the expected plati-
1JPt–P = 3500 Hz], which are consistent with two phos-
phorus cis- to each other and trans- to a chloride (see
Fig. 3).
Further monodentate complexes were synthesised
(Scheme 1) and these all exhibited the expected spectro-
scopic properties.
1
num satellites, JPt–P = 3870 Hz, consistent with phos-
phorus trans to chloride. The 1H NMR spectrum

H.L. Milton et al. / Polyhedron 23 (2004) 2575–2585
2577
is no interaction involving the oxygen or the sulfur
heteroatom in the ring. This could be due to the fact that
the sulfur is less likely to form a hydrogen bond, or that
the geometry of the five-membered ring as opposed to
that of the six-membered ring is less favourable for an
N(2)–H(2)ꢁ ꢁ ꢁS(5) interaction. These issues and the easy
availability of the chlorides account for the chosen motif
in this molecule. In the X-ray structure of 9 (Fig. 4), the
two hydrogen bonds present are almost identical, show-
ing the favourable motif that can be produced by trans-
coordination. 10 also has (Fig. 5) H-bond interactions
with a N(2)–H(2)ꢁ ꢁ ꢁCl(1) hydrogen bond controlling
the ligands geometry, forming a pseudo five-membered
ring, similar to the ones we have seen previously; again
the sulfur has no part in the bonding motif.
Dpptc also exhibits bidentate chemistry, though there
are significant differences between the chemistry of
dpppa and dpptc. Reaction of a halide abstraction rea-
gent with monodentate dpppa complexes gives the P,N
bidentate species. In the case of dpptc, when the same
reaction is undertaken one might expect the binding of
the thiophene sulfur atom or chelation via the C@O
group since thiophene is not an especially good ligand.
The coordination mode can be investigated by IR
spectroscopy, the frequency of the m(C@O) vibration
indicating chelation through the oxygen. The example
investigated was reaction of [RuCl2(p-cymene)(dpptc-
P)] with AgBF4 in CH2Cl2, the silver salt was removed
by filtration and the product [RuCl(p-Cy)(dpptc-
P,O)]BF4 (11) precipitated with diethylether. The 31P
NMR displays the expected downfield shift in the spec-
trum, the peak moves from d(P) 59.9–100.0 ppm, again
the chelate ring effect is responsible for this. The proton
spectrum shows some interesting aspects, as the amine
proton moves from d(H) 7.9 ppm in the monodentate
complex to d(H) 10.1 ppm in the bidentate complex
and changes from a doublet to a broad singlet, this is
typical of extensive hydrogen-bonding being present.
The m(NH) is unchanged in comparison with the mono-
dentate complex at 3216 cmꢀ1. The important IR data is
the m(C@O) – chelation would cause a high frequency
shift and this is observed with the band moving to
1561 cmꢀ1, a shift of 104 cmꢀ1 from the monodentate
complex, typical of C@O bound, bidentate ligand, as de-
scribed by Braunstein [5]. We also observed the [BF4]ꢀ
counterion in the IR spectrum.
Fig. 2. Crystal structure of [PdCl(g3-C3H5)(dpptc-P)] (5), selected
bond lengths (A) and angles (°): P(8)–Pd(1) 2.2937(14), Pd(1)–Cl(1)
2.3780(13), P(8)–N(7) 1.706(4), N(7)–C(6) 1.377(6), O(6)–C(6) 1.227(6)
C(6)–C(5) 1.455(8), S(1)–C(5), 1.712(6), N(7)ꢁ ꢁ ꢁCl(1) 3.166(4), P(8)–
Pd(1)–Cl(1) 97.18(4), C(15)–P(8)–Pd(1) 116.93(15), N(7)–P(8)–Pd(1)
106.26(14), C(9)–P(8)–Pd(1) 114.06(16), N(7)–H(7)ꢁ ꢁ ꢁCl(1) 131(4).
˚
The X-ray structure of 8 is in space group P212121
Flack parameter 0.01(3) but we have no evidence there
is only one isomer in solution. In 8 there is an interac-
tion between the amide proton and both chlorides at-
tached to the metal and it is worthy of note that there
+
Ru
Cl
Ru
AgBF4
-AgCl
PPh2
N
Cl
S
PPh2
Fig. 3. Crystal structure of [RhCl2(g5-C5Me5)(dpptc-P)] (8), selected
bond lengths (A) and angles (°): P(1)–Rh(1) 2.3077(10), Rh(1)–Cl(1)
2.3998(9), Rh(1)–Cl(2) 2.4163(9), P(1)–N(2) 1.695(3), O(3)–C(3)
1.218(4) N(2)–C(3) 1.387(4), N(2)ꢁ ꢁ ꢁCl(1) 3.379(3), N(2)ꢁ ꢁ ꢁCl(2)
3.113(3), P(1)–Rh(1)–Cl(1) 89.44(3), P(1)–Rh(1)–Cl(2) 89.19(3),
Rh(1)–P(1)–N(2) 106.88(10), Cl(1)–Rh(1)–Cl(2) 87.96(3), N(2)–
H(2)ꢁ ꢁ ꢁCl(1) 112(3), N(2)–H(2)ꢁ ꢁ ꢁCl(2) 121(3).
Cl
O
O
N
H
˚
H
BF4
S
ð2Þ

2578
H.L. Milton et al. / Polyhedron 23 (2004) 2575–2585
O
H
S
N
P
Me
Pt
Cl
PPh2
N
O
N
S
H
Ph
P2
N
S
Rh
O
Cl
9
PPh2
N
H
Pd
Cl
O
Cl
10
[{Pd(µ-Cl)(C9H12N)}2]
H
[PtClMe(cod)]
H
S
[{RhCl(µ-Cl)(η6-C5Me5)}2]
8
N
S
PPh2
[{Pd(µ-Cl)(C3H5)}2]
O
[{RuCl(µ-Cl)(η6-p-Cymene)}2]
Pd
H
Cl
PPh2
N
[{PtCl(µ-Cl)(PPhMe2)}2]
O
Ru
Cl
PPh2
N
Cl
S
Cl
Pt
Cl
PPhMe2
PPh2
O
H
S
5
N
O
H
7
S
6
Scheme 1. Formation of monodentate complexes of dpptc.
The synthesis of bdpppa (12) is very similar to that of
dpppa (Eq. (3)).
with a more or less identical shift to dpppa at d(H) 8.4
ppm, however the coupling constant is significantly lar-
ger for bdpppa, being 8 Hz as compared to 4 Hz for
dpppa. When one examines the IR spectra for bdpppa
we see some significant deviation in the characteristics
of bdpppa compared to dpppa. In bdpppa m(N–H) vibra-
tions are visible at 3345 and 3262 cmꢀ1, this trend contin-
ues into the m(C@O) vibrations – again two are visible at
1665 and 1646 cmꢀ1, the m(C@N) stretches are also
twinned at 1588 and 1571 cmꢀ1. However there is only
one m(P–N) vibration observed at 999 cmꢀ1; from this
we could surmise that there is a slight difference in the
to ꢀarmsꢁ of the molecule present in the solid state.
The presence of two PIII atoms in this molecule pro-
vides an opportunity for a variety of oxidation products
to be synthesised. Bis(2,6-diphenylphosphino)picolina-
mide disulfide (13) and the diselenide (14) were prepared
by refluxing bdpppa in toluene with a stoichiometric
amount of sulfur or selenium for 1 h, the disulfide has
H2N
NH2
N
O
O
H
H
Ph2PCl, Et3N
thf, reflux
N
N
Ph2P
PPh2
N
O
O
12
ð3Þ
The expected singlet in the 31P NMR is observed at
d(P) 21.9 ppm. This is extremely close to the value for
dpppa (22.0 ppm). We see the same similarities in the
proton spectra, the N–H peak appears again as a doublet

H.L. Milton et al. / Polyhedron 23 (2004) 2575–2585
2579
˚
Fig. 4. Crystal structure of [PtMeCl(dpptc-P)2] (9), selected bond lengths (A) and angles (°): P(1)–Pt(1) 2.2902(15), P(31)–Pt(1) 2.2902(15), P(1)–N(2)
1.702(5), P(31)–N(32) 1.700(5), N(2)–C(3) 1.371(8), N(32)–C(33) 1.365(7), C(3)–O(3) 1.227(7), C(33)–O(33) 1.227(7), Pt(1)–Cl(1) 2.4343(16), Pt(1)–
C(1) 2.074(6) N(2)ꢁ ꢁ ꢁCl(1) 3.085(6), N(32)ꢁ ꢁ ꢁCl(1) 3.045(5), P(1)–Pt(1)–Cl(1) 91.72(5), P(31)–Pt(1)–Cl(1) 90.34(5), P(1)–Pt(1)–C(1) 89.79(18), N(2)–
P(1)–Pt(1) 106.14(18), N(32)–P(31)–Pt(1) 106.14(18), N(2)–H(2)ꢁ ꢁ ꢁCl(1) 139(4), N(32)–H(32)ꢁ ꢁ ꢁCl(1) 139(5).
data shows no real variation from the dpppa equiva-
lents, for 13 the m(N–H) is observed at 3360 cmꢀ1 as a
sharp peak, however the m(C@O) is observed at 1697
cmꢀ1 with significant line broadening, the m(P–N) peak
remains constant at 999 cmꢀ1. A similar pattern is ob-
served for 14, with m(N–H), m(C@O) and m(P–N) coming
at 3256, 1698 and 998 cmꢀ1, respectively, although the
slightly lower value for the m(N–H) may suggest more
extensive hydrogen-bonding in 14 compared to both
the disulfide and the free ligand. In the solid state
(Fig. 6) 14 adopts a pseudo five-membered ring formed
by an interaction of the amide hydrogenꢁs with the pyr-
idyl nitrogen (see Scheme 2).
By making use of the mild conditions involved in syn-
thesis of the sulfur species one can isolate the mono-sul-
fur derivative of bdpppa, bdpppa-S (15). This generates
a compound where only one sulfur is bound to phospho-
rus, leaving one free for further chemistry. The 31P spec-
trum clearly shows this motif with two singlets being
present at d(P) 56.0 (P@S), and 21.7 ppm (PIII). The
IR data shows the two now different arms of the mole-
cule clearly, two m(N–H) vibrations are observed, one
at 3345 cmꢀ1 which is consistent with bdpppa, and the
other at 3262 cmꢀ1, similar to dpppa-S and bdpppa-
diS. The same pattern is seen in the m(C@O), a peak at
1697 cmꢀ1 representing the sulfide arm, and a peak at
1665 cmꢀ1 represents the PIII arm.
As we speculated the mono-oxidised form of bdpppa
can use it is unoxidised phosphorus to react further, and
reaction with one equivalent of selenium in toluene gen-
erates the unsymmetrical bdpppa-S,Se (16), d(P) 55.0
Fig. 5. Crystal structure of [PdCl(C9H12N)(dpptc-P)] (10), Selected
˚
bond lengths (A) and angles (°): P(1)–Pd(1) 2.2479(12), Pd(1)–N(31)
2.143(4), Pd(1)–Cl(1) 2.4249(12), C(3)–O(3) 1.219(5), N(2)–C(3)
1.382(5), C(4)–S(5) 1.713(4), N(2)ꢁ ꢁ ꢁCl(1) 3.027(4), P(1)–Pd(1)–Cl(1)
93.58(4), P(1)–Pd(1)–N(31) 173.10(10), Cl(1)–Pd(1)–N(31) 91.83(10),
N(2)–H(2)ꢁ ꢁ ꢁCl(1) 141(4).
d(P) 55.1 ppm and the diselenide d(P) 49.7 ppm with
1JP@Se = 795 Hz. The amide protons in 13 and 14 are
shifted to d(H) 8.9 and 8.8 ppm, respectively, and are
both doublets with 2JP–H = 9 Hz, these values are similar
to the values observed for the unoxidized ligand. The IR

2580
H.L. Milton et al. / Polyhedron 23 (2004) 2575–2585
[AuCl(bdpppa-S-P)] 17, d(P) 55.0 (P@S) and d(P) 50.2
(P–Au). Reaction of bdpppa with [AuCl(tht)] in dichlo-
romethane gives two products dependant on the stoichi-
ometry of the reaction. One equivalent of [AuCl(tht)]
generates the expected product with one phosphorus
bound to gold and one remaining unbound (18). With
two equivalents of [AuCl(tht)] both phosphorus atoms
are coordinated (Scheme 3) to give (19). In the case of
this digold complex, we see the expected singlet in the
31P NMR at 50.0 ppm, this agrees well with the one pre-
vious gold complex of dpppa, and the peak seen in 17.
The proton spectrum also displays the characteristics
of its dpppa analogue, the amide peak is clearly seen
at d(H) 10.3 ppm with a 2JP–H = 16 Hz and the aromat-
ics are all found in the 8.2–7.2 region. The m(N–H)
stretch in the IR spectrum is a broad peak at 3261
cmꢀ1, also the m(C@O) band is broad, located at 1698
cmꢀ1, both these values correlate well with [AuCl(dpp-
pa-P)] (3288 and 1698 cmꢀ1, respectively).
Fig. 6. Crystal structure of bdpppa-diSe (14), selected bond lengths
˚
(A) and angles (°): P(2)–Se(1) 2.0974(14), P(13)–Se(14) 2.1014(15),
P(2)–N(3) 1.687(4), P(13)–N(12) 1.698(4), N(3)–C(4) 1.374(6), N(12)–
C(11) 1.373(6), C(4)–O(4) 1.209(6), C(11)–O(11) 1.207(6), C(4)–C(5)
1.513(6), C(11)–C(9) 1.510(7), C(5)–N(10) 1.334(6), C(9)–N(10)
1.334(16), N(3)ꢁ ꢁ ꢁCl(3) 3.050, N(12)ꢁ ꢁ ꢁCl(3) 3.368, N(3)ꢁ ꢁ ꢁN(10)
2.684(5) N(12)ꢁ ꢁ ꢁN(10) 2.721(5), Se(1)–P(2)–N(3) 107.68(16), Se(14)–
P(13)–N(12) 114.97(16), P(2)–N(3)–H(3) 120(5), N(3)–H(3)ꢁ ꢁ ꢁN(10)
113(5), N(12)–H(12)ꢁ ꢁ ꢁN(10) 113(5).
However, when one considers the mono-gold com-
plex it, unlike 15, does not display two separate peaks
in the 31P NMR for P–Au and PIII, it displays a singlet
at d(P) 64.3 ppm, at significantly higher chemical shift
than anything we have seen earlier, and does not corre-
late with the shift observed in the mono-sulfide/gold
complex. Inspection of the IR data provides further evi-
dence for a single phosphorus environment, with only
single peaks being displayed for m(N–H) and m(C@O)
ppm (consistent with P@S), d(P) 49.7 ppm 1JP@Se of 795
Hz.. Compound 15 can also be reacted with one equiv-
alent of [AuCl(tht)] in dichloromethane to generate
1
(3054 and 1698 cmꢀ1, respectively). Also the H NMR
S or Se
H
H
H
H
N
N
N
N
Ph2P
PPh2
S
N
Ph2P
E
PPh2
E
N
two equivalents
O
O
O
O
E = S (3.13)
E = Se (3.14)
one equvilent
H
H
N
N
Ph2P
PPh2
N
O
O
S
[AuCl(tht)]
15
Se
H
H
N
N
Ph2P
Au
Cl
PPh2
S
H
H
N
N
N
Ph2P
PPh2
N
O
O
Se
O
S
O
17
16
Scheme 2. Reactions of bdpppa and its mono-oxidized derivatives.

H.L. Milton et al. / Polyhedron 23 (2004) 2575–2585
2581
H
N
H
N
Ph2P
N
PPh2
O
O
2 [AuCl(tht)]
[AuCl(tht)]
H
H
H
H
N
N
N
N
Ph2P
Au
Cl
N
PPh2
Ph2P
N
PPh2
Au
O
O
Au
Cl
O
O
Cl
18
19
Fig. 7. Crystal structure of [Pt2Cl2(g-C3H5)2(bdpppa-P,P)] (21),
selected bond lengths (A) and angles (°): P(2)–Pt(1) 2.249(2), P(13)–
Scheme 3. Reaction of bdpppa with [AuCl(tht)].
˚
Pt(14) 2.250(2), P(2)–N(3) 1.699(7), P(13)–N(12) 1.720(7),
N(3)ꢁ ꢁ ꢁN(10) 2.689(10), N(12)ꢁ ꢁ ꢁCl(14) 3.167(7), N(12)ꢁ ꢁ ꢁN(10)
2.674(9), Pt(1)–P(2)–N(3) 110.4(2), Pt(14)–P(13)–N(12) 109.9(3),
N(3)–H(3)ꢁ ꢁ ꢁN(10) 119(7), N(12)–H(12)ꢁ ꢁ ꢁN(10) 110(6).
data shows a single resonance for the amide proton, a
broad singlet at d(H) 11.0 ppm. The most plausible
explanation for these data is for 18 to exist as a dimer,
this is not a unique conformation as a similar system
has been reported for dppap [13].
Reaction of bdpppa with a range of Pt and Pd dimers
generates complexes where the bdpppa ligand bridges
two metal atoms. Treatment of bdpppa with one equiv-
alent of [{Pd(l-Cl)(g-C3H5)}2], generating [Pd2Cl2(g-
C3H5)2(bdpppa-P,P)] (20). The 31P NMR shows a
singlet at d(P) 55.1 ppm, consistent with the complexes
structure when compared to dpppa and dpptc.
to 14 one can imagine in this scenario that there is prob-
ably too much steric bulk involved for both of the chlo-
rides to occupy the ꢀinꢁ slot as was the case with the
selenium atoms.
3. Experimental
All manipulations were carried out in a atmosphere
of nitrogen, unless stated otherwise. All solvents were
either freshly distilled from an appropriate drying agent
(thf, Et2O, dcm) or obtained as anhydrous grade from
H
H
N
N
Ph2P
N
PPh2
1
Aldrich. H and 31P NMR spectra were recorded using
O
O
a Jeol Delta FT (270 MHz) spectrometer. IR spectra
were recorded as KBr discs (prepared in air) on a Per-
kin–Elmer 2000 FTIR/RAMAN spectrometer. All sig-
nificant peaks (>800 cmꢀ1) are quoted to serve as a
fingerprint. Silver salts, 2-thiophenecarboxamide, 2,6-
pyridinedicarboxamide (Aldrich Chemical Co.) and
BuLi (2.5 M, Lancaster) were purchased and used as re-
ceived. Triethylamine and chlorodiphenylphosphine
were distilled prior to use. Dimethylaminopyridine
(DMAP) was sublimed before use. The various metal
starting materials were made by the appropriate litera-
ture methods; [AuCl(tht)] [5], [MCl2(cod)] (M = Pt or
Pd; cod = cycloocta-1,5-diene) [6,7], [PtMeCl(cod)] [8],
[{Pd(µ-Cl)(η3-C3H5)}2]
H
H
Pd
N
N
Pd
Cl
P
N
P
Ph2
Cl
Ph2
O
O
20
ð4Þ
The analogous reaction with [{Pt(l-Cl)(g-C3H5)}2]
generated a similar product, [Pt2Cl2(g-C3H5)2(bdpppa-
P,P)] (21), d(P) 51.7 ppm, JPt–P = 4730 Hz. A crystal
of 21 was prepared for crystallographic analysis by va-
pour diffusion of diethylether into a concentrated solu-
tion of 21 in CDCl3. Given our conclusions based on
20, we could imagine the two compounds would be al-
most analogous in the solid state.
1
[{PtCl(l-Cl)(PMe2Ph)}2]
[9],
(M = Rh or Ir) [10], [{RuCl(l-Cl)(g6-p-MeC6H4 Pr)}2]
[11], [{PdCl(l-Cl)(g3-C3H5)}2] [12–14].
[{MCl(l-Cl)(Cp*)}2]
i
The X-rays structure of 21 (Fig. 7) shows it has an
arrangement much like that of 14, with the amide pro-
tons interacting with the pyridyl nitrogen, and if one
considers the chlorides to be analogous to the selenium
atoms, then we can see that again one is ꢀinꢁ and one is
ꢀoutꢁ, of the hole in the centre of the complex. Similar
3.1. 2-(Diphenylphosphino)thiophenecarboxamide(Dpptc)
(1)
Chlorodiphenylphosphine (3.53 ml, 20 mmol) was
added to a solution of 2-thiophenecarboxamide (2.5 g,

2582
H.L. Milton et al. / Polyhedron 23 (2004) 2575–2585
20 mmol), triethylamine (2.88 ml, 20.6 mmol) and
DMAP (240 mg, 2 mmol) in THF (100 cm3) and ref-
luxed overnight. The reaction mixture was filtered to re-
move a white solid (Et3NHCl) and washed with THF
(50 cm3). The solvent was removed in vacuo leaving a
pale yellow solid. This solid was recrystallised by cooling
a concentrated methanol solution in a fridge overnight
(yield: 3.28 g, 10.5 mmol, 54%). Anal. Calc.
C17H14NOSP requires: C, 65.5; H, 4.53; N, 4.50. Found:
C, 63.8; H, 4.09; N, 4.70%. mmax/cmꢀ1: 3265, 1624, 1522,
1442, 1270, 1096, 996. 31P NMR (109.3 MHz, CDCl3), d
48.3; H, 2.35; N, 2.82%. mmax/cmꢀ1: 3208, 1671, 1435,
1394, 1010, 277. 31P NMR (109.3 MHz, CDCl3), d
54.3. H NMR (270 MHz, CDCl3), 9.4 (1H, d, J = 19
Hz, N–H), 7.7 (1H, d, J = 1 Hz, thC[5**]H), 7.7–7.6
(4H, m, aromatic), 7.5–7.3 (7H, m, aromatic) 7.1 (1H,
dd, J = 3, 6 Hz, thC[4**]) 5.5 (1H, m, allyl), 4.8 (1H,
t, J = 6 Hz, allyl), 3.7 (1H, dd, J = 10, 13 Hz, allyl),
3.3 (1H, obscured, allyl), 2.6 (1H, d, J = 13 Hz, allyl).
1
3.5. [PtCl2(PPhMe2)(dpptc-P)] (6)
1
25.9. H NMR (270 MHz, CDCl3), 7.6 (2H, m, aro-
matic), 7.5–7.3 (10H, m, aromatic), 7.1 (2H, m,
aromatic).
Dpptc (58 mg, 0.18 mmol) and [{PtCl(l-
Cl)(Me2PhP)}2] (75 mg, 0.0927 mmol) were weighed
into a Schlenk type flask and DCM (5 cm3) added.
The solution was stirred for 10 min and the majority
of the solvent removed in vacuo. A yellow solid was iso-
lated after addition of Et2O then filtered and washed
with further ether (yield: 66 mg, 50%). Anal. Calc.
C25H25NOSP2Cl2Pt requires: C, 39.7; H, 4.20; N, 2.01.
Found: C, 40.0; H, 3.31; N, 1.72%. mmax/cmꢀ1: 3226,
1671, 1435, 948, 316, 281. 31P NMR (109.3 MHz,
CDCl3) d 29.7 (d, JP–P = 18.78 Hz, JP–Pt = 3890 Hz), -
15.6 (d, JP–P = 18.78 Hz, JP–Pt = 3500 Hz). 1H NMR
(270 MHz, CDCl3) d 11.4 (1H, d, J = 16 Hz, N–H),
8.6 (1H, d, J = 7 Hz, pyC[6]H), 8.2 (4H, m, aromatic),
7.9–7.4 (9H, m, aromatic), 1.6–1.4 (9H, m, Me–H)
1.0–0.8 (6H, m, –CH2–).
3.2. 2-(Diphenylphosphino)thiophenecarboxamide sulfide
(3)
Sulfur (77 mg, 2.4 mmol) was added to a solution of
2-(diphenylphosphino)thiophenecarboxamide (750 mg,
2.4 mmol) in toluene (20 cm3) and refluxed overnight.
The solvent was removed in vacuo leaving an off-white
solid. This solid was recrystallised by cooling a concen-
trated toluene solution at 4 °C overnight (yield: 1.39 g,
93%). Anal. Calc. C17H14NOPS2 requires: C, 59.5; H,
4.11; N, 4.08. Found: C, 59.2; H, 3.70; N, 4.48%. mmax
/
cmꢀ1: 3167, 1624, 1436, 1000. 31P NMR (109.3 MHz,
1
CDCl3), d 57.2 ppm. H NMR (CDCl3), d 8.0 (3H, m,
aromatic), 7.7–7.3 (6H, m, aromatic), 7.3–7.1 (4H, m,
aromatic), 7.0 (1H, d, N–H).
3.6. [RuCl2(p-Cymene)(dpptc-P)] (7)
Dpptc (102 mg, 0.326 mmol) and [{RuCl(l-Cl)(p-
Cymene)}2] (100 mg, 0.0163 mmol) were weighed into
a Schlenk type flask and DCM (5 cm3) added. The solu-
tion was stirred for 10 min and the majority of the sol-
vent removed in vacuo. A red solid was isolated after
addition of Et2O then filtered and washed with further
ether (yield: 155 mg, 77%). Anal. Calc. C27H28NOPCl2-
Ru requires: C, 52.5; H, 4.57; N, 2.27. Found: C, 52.1;
H, 3.48; N, 2.19%. mmax/cmꢀ1: 3312, 1665, 1435, 1404,
3.3. [PtCl2(dpptc-P)2] (4)
Dpptc (166 mg, 0.534 mmol) and [PtCl2(cod)] (100
mg, 0.267 mmol) were weighed into a Schlenk type flask
and DCM (5 cm3) added. The solution was stirred for 10
min and the majority of the solvent removed in vacuo. A
white solid was isolated after addition of Et2O then fil-
tered and washed with further ether (yield: 170 mg,
72%). Anal. Calc. C34.5H29N2O2P2S2Cl3Pt requires: C,
44.5; H, 3.14; N, 3.01. Found: C, 44.0; H, 3.89; N,
2.95%. mmax/cmꢀ1: 3214, 1672, 1424, 1398, 1042, 304,
273. 31P NMR (109.3 MHz, CDCl3), d 27.9 (JP–
1
1091, 288. 31P NMR (109.3 MHz, CDCl3), d 59.9. H
NMR (270 MHZ, CDCl3), 8.0 (5H, m, aromatic) 7.9
(1H, d, J = 14 Hz, N–H), 7.6 (1H, dd, J = 1, 4 Hz),
7.5–7.3 (10H, m, Aromatic), 5.3–5.2 (4H, m, p-Cy), 2.5
(1H, m, C–H), 1.9 (3H, s, Me–H), 0.8 (6H, d, J = 7Hz,
IPr–H).
1
Pt = 3870 Hz). H NMR (270 MHZ, CDCl3), 9.7 (2H,
d, J = 11 Hz, N–H), 7.8–6.9 (26H, m, aromatic).
3.4. [PdCl(g3-C3H6)(dpptc-P)] (5)
3.7. [RhCl2(g5-C5Me5)(dpptc-P)] (8)
Dpptc (170 mg, 0.54 mmol) and [{Pd(l -Cl)(g3-
C3H5)}2] (100 mg, 0.27mmol) were weighed into a
Shlenk type flask and DCM (5 ml) added. The solution
was stirred for 10 min and the majority of the solvent re-
moved in vacuo. A white solid was isolated after addi-
tion of Et2O then filtered and washed with further
ether (yield: 117 mg, 87%). Anal. Calc. C20H20NOS-
PClPd requires: C, 48.5; H, 4.07; N, 2.83. Found: C,
Dpptc (101 mg, 0.326 mmol) and [{RhCl(l-Cl)(g5-
C5Me5)}2] (100 mg,. 0161 mmol) were weighed into a
Schlenk type flask and DCM (5 cm3) added. The solu-
tion was stirred for 10 min and the majority of the sol-
vent removed in vacuo. A red solid was isolated after
addition of Et2O then filtered and washed with further
ether (yield: 159 mg, 80%). C27.5H30NSOPCl3Rh re-
quires: C, 49.8; H, 4.56; N, 2.11. Found: C, 50.7; H,

H.L. Milton et al. / Polyhedron 23 (2004) 2575–2585
2583
4.17; N, 2.27%. mmax/cmꢀ1: 3299, 1669, 1435, 1097, 246,
(11H, m, aromatic), 5.9 (1H, dd, J = 7 Hz, p-Cy-H),
5.6 (1H, dd, J = 6 Hz, p-Cy-H), 5.3 (1H, m, p-Cy), 5.0
(1H, d, J = 6 Hz, p-Cy), 2.6 (1H, m, C–H), 2.1 (3H, s,
Me–H), 1.3 (6H, m, Pri–H).
231. 31P NMR (109.3 MHz, CDCl3), d 63.5 (1JRh–P
=
148 Hz).. 1H NMR (270 MHZ, CDCl3), 8.2 (1H, d,
J = 14 Hz, N–H) 8.1–8.0 (4H, m, aromatic) 7.7 (1H, d,
J = 4 Hz, N–H), 7.5–7.3 (7H, m, aromatic), 7.0 (1H, t,
J = 8 Hz, aromatic), 1.4 (15H, d, Cp*Me–H).
3.11. Bis(2,6-diphenylphosphino)picolinamide (bdpppa)
(12)
3.8. [PtClMe(dpptc-P)2] (9)
Chlorodiphenylphosphine (5.44 cm3, 30.3 mmol) was
added to a solution of 2,6-pyridinedicarboxamide (2.5 g,
30.3 mmol), triethylamine (4.44 cm3, 32 mmol) and
DMAP (370 mg, 3.0 mmol) in thf (100 cm3) and refluxed
overnight. The reaction mixture was filtered to remove a
white solid (Et3NHCl) and washed with thf (50 cm3).
The solvent was removed in vacuo leaving a pale yellow
solid. This solid was recrystallised by cooling a concen-
trated methanol solution at 4 °C overnight (yield: 4.89 g,
61%). Anal. Calc. C31.5H26N3O2P2Cl requires: C, 66.0;
H, 4.50; N, 7.22. Found: C, 65.7; H, 4.41; N, 7.40%.
Dpptc (39 mg, 0.12 mmol) and [PtClMe(cod)] (22 mg,
0.06 mmol) were weighed into a Schlenk type flask and
DCM (5 cm3) added. The solution was stirred for 10 min
and the majority of the solvent removed in vacuo. A yel-
low solid was isolated after addition of Et2O then fil-
tered and washed with further ether (yield: 34 mg,
65%). Anal. Calc. C35H31N2S2O2P2ClPt requires: C,
48.4; H, 3.60; N, 3.23. Found: C, 48.4; H, 3.40; N,
3.17%. mmax/cmꢀ1: 3209, 1671, 1435, 1094. 31P NMR
(109.3 MHz, CDCl3), d 49.1 (JP–Pt = 3220 Hz). 1H
NMR (270 MHZ, CDCl3), 9.7 (2H, t, JPt–H = 19 Hz,
N–H), 7.9 (10H, m, aromatic), 7.6–7.3 (14H, m, aro-
matic), 7.1 (2H, d, J = 3 Hz, thiophene), 1.5 (3H, s, Me).
m
max/cmꢀ1: 3345, 3262, 1665, 1646,, 1588, 1571, 1408,
1
999. 31P NMR (CDCl3) 21.9. H NMR (CDCl3), 8.42
(2H, d, J = 8 Hz, N–H), 8.00 (3H, m, py), 7.5–7.1
(21H, m, aromatic).
3.9. [PdCl(C9H12N)(dpptc-P)] (10)
3.12. Bis(2,6-diphenylphosphino)picolinamide disulfide
(13)
Dpptc (79 mg, 0.25 mmol) and [Pd(l-Cl)(C9H12N)]2
(70 mg, 0.13 mmol) were weighed into a Schlenk type
flask and DCM (5 cm3) added. The solution was stirred
for 10 min and the majority of the solvent removed in
vacuo. A yellow solid was isolated after addition of
Et2O then filtered and washed with further ether (yield:
82 mg, 55%). Anal. Calc. C26H26N2SOPClPd requires:
C, 53.0; H, 4.63; N, 4.76. Found: C, 52.3; H, 4.52; N,
4.53%. mmax/cmꢀ1: 3171, 1672, 1438, 1259, 1101, 286.
Sulfur (120 mg, 3.7 mmol) was added to a solution of
bis(2,6-diphenylphosphino)picolinamide (1 g, 3.7 mmol)
in toluene (20 cm3) and refluxed for 10 min. The solvent
was removed in vacuo leaving an off-white solid. This
solid was recrystillised by cooling a concentrated toluene
solution at 4 °C overnight (yield: 876 mg, 78%). Anal.
Calc. C31H25N3O2P2S2 requires: C, 63.8; H, 4.32; N,
31P NMR (109.3 MHz, CDCl3), d 62.4ppm. H NMR
4.80. Found: C, 64.1; H, 4.46; N, 4.50%. mmax/cmꢀ1
:
1
(270 MHZ, CDCl3), 10.1 (1 H, bs, N–H) 8.2 (4 H, m,
aromatic) 7.2–7.7 (10H, m, aromatic), 7.1 (1H, dd,
J = 1, 4 Hz, aromatic) 7.0 (1H, d, J = 6 Hz, aromatic),
6.8 (1H, t, J = 15 Hz, aromatic) 6.4 (2H, m, aromatic)
2.9 (6H, s, N–Me).
3360, 1697, 1424, 999. 31P NMR (CDCl3) 55.1 ppm.
1H NMR (CDCl3), d 8.9 (2H, d, J = 9 Hz, N–H), 8.3
(2H, d, J = 8 Hz, pyC[3,5]H), 8.1–7.9 (8H, m, aromatic),
7.6–7.4 (10H, m, aromatic), 7.1–7.3 (3H, m, aromatic).
3.13. 2,5-bis(Diphenylphosphino)picolinamide diselenide
(14)
3.10. [RuCl(p-Cy)(dpptc-P,O)]BF4 (11)
AgBF4 (22 mg, 0.11 mmol) was added under dark
conditions to a solution of [RuCl2(p-Cy)(dpptc-P)] (70
mg, 0.11 mmol) in DCM (5 cm3). The solution was stir-
red overnight and filtered through a celite bed. The
majority of the solvent was removed in vacuo. An or-
ange solid was isolated after addition of Et2O then fil-
tered and washed with further ether (yield: 45 mg,
70%). Anal. Calc. C27H28NRuClOSPBF4 requires: C,
48.48; H, 4.21; N, 2.09. Found: C, 48.0; H, 4.07; N,
2.02%. mmax/cmꢀ1: 3216, 1561, 1460, 1433, 1084, 1060,
Selenium (74 mg, 0.9 mmol) was added to a solution
of 2,5-bis(Diphenylphosphino)picolinamde (250 mg,
0.47 mmol) in toluene (20 cm3) and refluxed for 10
min. The solvent was removed in vacuo leaving an off-
white solid. This solid was recrystillised by cooling a
concentrated toluene solution in a fridge overnight
(yield: 263 mg, 81%). Anal. Calc. C31H25N3O2P2Se2 re-
quires: C, 53.9; H, 3.64; N, 6.08. Found: C, 53.7; H,
3.24; N, 6.17%. mmax/cmꢀ1: 3256, 1698, 1421, 998. 31P
NMR (109.3 MHz, CDCl3), d 49.6 (1JP@Se = 795 Hz).
1H NMR (270 MHz, CDCl3), d 8.8 (2H, d, J = 9Hz,
N–H), 8.3 (1H, d, J = 8Hz, pyC[6]H), 8.0 (8H, m, aro-
matic), 7.5 (13H, m, aromatic).
1
764. 31P NMR (109.3 MHz, CDCl3) d 100.0. H NMR
(270 MHz, CDCl3) d 10.1 (1H, s, N–H), 8.3 (1H, d,
J = 3Hz, thC[5]H), 8.0 (2H, m, aromatic), 7.7–7.1

2584
H.L. Milton et al. / Polyhedron 23 (2004) 2575–2585
3.14. Bis(2,6-diphenylphosphino)picolinamidemonosul-fide
(15)
P2AuCl requires: C, 48.6; H, 3.29; N, 5.49. Found: C,
48.2; H, 2.91; N, 5.48%. mmax/cmꢀ1: 3054, 1698, 1436,
1
999. 31P NMR (CDCl3) d(P) 64.3. H NMR (CDCl3)
Sulfur (36 mg, 0.37 mmol) was added to a solution of
bis(2,6-diphenylphosphino)picolinamide (600 mg, 0.37
mmol) in toluene (20 cm3) and refluxed for 10 min.
The solvent was removed in vacuo leaving an off-white
solid. This solid was recrystallised by cooling a concen-
trated toluene solution at 4 °C overnight (yield: 415 mg,
65%). Anal. Calc. C31H25N3O2P2S requires: C, 65.7; H,
d(H) 11.0 (2H, bs, N–H), 9.0 (2H, m, aromatic), 7.1–
8.1 (21H, m, aromatic).
3.18. [{AuCl}2(bdpppa)] (19)
[AuCl(tht)] (84 mg, 0.26 mmol) and bis(2,6-diph-
enylphosphino)picolinamide (70 mg, 0.13 mmol) were
added to a round bottomed flask and DCM (5 cm3)
added. The solvent volume was reduced to ꢂ1 cm3
and the product precipitated with n-hexane (20 cm3).
Yield 125 mg, 95%. Anal. Calc. C31H25N3O2P2Au2Cl2
requires: C, 37.3; H, 2.52; N, 4.21. Found: C, 37.16;
H, 2.37; N, 4.12%. mmax/cmꢀ1: 3261, 1697, 1436, 999.
4.46; N, 7.43. Found: C, 67.4; H, 4.47; N, 7.20%. mmax
/
cmꢀ1: 3345, 3262, 1697, 1665, 1646, 1432, 999. 31P
1
NMR (CDCl3) 56.0 (s, P@S), 21.7 (s, PIII). H NMR
(CDCl3), d 8.8 (2H, d, J = 9 Hz, N–H), 8.4 (4H, m aro-
matic), 7.8–8.1 (5H, m, aromatic), 7.0–7.6 (14H, m,
aromatic).
1
31P NMR (CDCl3) d(P) 50.0. H NMR (CDCl3) d(H)
3.15. Bis(2,6-diphenylphosphino)picolinamide monosulfide
monoselenide (16)
10.2 (2H, d, JH–H = 16 Hz, N–H), 8.1 (2H, m, aromatic),
7.9–7.6 (8H, m, aromatic), 7.6–7.1 (13H, m, aromatic).
Selenium (22 mg, 0.26 mmol) was added to a solution
of bis(2,6-diphenylphosphino)picolinamide monosulfide
(150 mg, 0.26 mmol) in toluene (10 cm3) and refluxed for
10 min. The solvent was removed in vacuo leaving an
off-white solid. This solid was recrystillised by cooling
a concentrated toluene solution at 4 °C overnight (yield:
120 mg, 71%). Anal. Calc. C31H25N3O2P2SSe requires:
C, 57.7; H, 3.91; N, 6.52. Found: C, 58.8; H, 3.68; N,
6.30%. mmax/cmꢀ1: 3449, 1697, 1421, 997. 31P NMR
3.19. [Pd2Cl2(allyl)2(bdpppa-P,P)] (20)
Bdpppa (397 mg, 0.7.45 mmol) and [{Pd(l-Cl)(g3-
C3H5)}2] (272 mg, 0.373 mmol) were weighed into a Sch-
lenk type flask and DCM (10 cm3) added. The solution
was stirred for 10 min and the majority of the solvent re-
moved in vacuo. A white solid was isolated after addi-
tion of Et2O then filtered and washed with further
ether (yield: 671 mg, 91%). Anal. Calc. C37H37N3O2-
P2Cl2Pd2 requires: C, 49.3; H, 4.13; N, 4.66. Found:
C, 49.23; H, 3.68; N, 4.57%. mmax/cmꢀ1: 3351, 3209,
1698, 1434, 1385, 999. 31P NMR (109.3 MHz, CDCl3),
d 55.1. 1H NMR (270 MHZ, CDCl3), 10.2 (2H, d,
J = 18 Hz, N–H), 8.2 (2H, d, J = 8 Hz, –pyC[6]H),
8.0–7.8 (10H, m, aromatic), 7.6–7.4 (10H, m, aromatic),
5.5 (4H, quin, J = 10 Hz, allyl), 4.7 (4H, t, J = 7Hz, al-
lyl), 3.7 (2H, t, J = 10 Hz, allyl).
1
(CDCl3) 55.0 (s, P@S), 49.7 (s, P@Se, JP–Se = 789
1
Hz). H NMR (CDCl3), d 8.8 (2H, d, J = 8 Hz, N–H),
8.3 (2H, dd, J = 8, 1 Hz, pyC[3,5]H), 7.9-8.1 (7H, m,
aromatic), 7.6–7.4 (14H, m, aromatic).
3.16. [{AuCl}(bdpppa-S)] (17)
[AuCl(tht)] (57 mg, 0.17 mmol) and Bis(2,6-diph-
enylphosphino)picolinamide (100 mg, 0.17 mmol) were
added to a round bottomed flask and DCM (5 cm3)
added. The solvent volume was reduced to ꢂ1 cm3
and the product precipitated with n-hexane (20 cm3).
Yield 93 mg, 66%. Anal. Calc. C32H26N3O2P2SAuCl3 re-
quires: C, 41.9; H, 2.80; N, 4.58. Found: C, 41.7; H,
2.74; N, 4.69%. mmax/cmꢀ1: 3256, 1697, 1437, 999. 31P
3.20. [Pt2Cl2(allyl)2(bdpppa-P,P)] (21)
Bdpppa (59 mg, 0.092 mmol) and [{Pt(l-Cl)(g3-
C3H5)}2] (60 mg, 0.046 mmol) were weighed into a Sch-
lenk type flask and THF (5 cm3) added. The solution
was stirred for 10 min and the majority of the solvent re-
moved in vacuo. A white solid was isolated after addi-
tion of Et2O then filtered and washed with further
ether (yield: 43 mg, 43%). Anal. Calc. C37H37N3O2-
P2Cl2Pt2 requires: C, 41.1; H, 3.46; N, 3.90. Found: C,
40.3; H, 3.59; N, 3.86%. mmax/cmꢀ1: 3360, 3231, 1700,
1434, 1000. 31P NMR (109.3 MHz, CDCl3), d 51.7
1
NMR (CDCl3) d(P) 55.0 (s, P@S), 50.2 (s, P–Au). H
NMR (CDCl3) d (H) 10.2 (2H, bs, N–H), 7.0–8.0
(23H, m, aromatic).
3.17. [{AuCl} (bdpppa)] (18)
1
A solution of [AuCl(tht)] (120 mg, 0.37mmol) in
DCM (10 cm3) was dropped into a solution of bis(2,6-
diphenylphosphino)picolinamide (200 mg, 0.37 mmol)
in DCM (15 cm3). The solvent volume was reduced to
ꢂ1cm3 and the product precipitated with n-hexane
(20cm3). Yield 240 mg, 83%. Anal. Calc. C31H25N3O2-
(1JPt–P = 4730Hz). H NMR (270 MHz, CDCl3), 10.2
(2H, d, J = 10 Hz, N–H), 8.2 (2H, d, J = 8Hz,
pyC[**6]H), 8.0–7.8 (10H, m, aromatic), 7.7–7.3 (12H,
m, aromatic), 5.3 (2H, m, allyl), 5.0 (2H, m, allyl), 4.3
(2H, m, allyl), 3.2 (2H, m, allyl), 3.0 (2H, m, allyl), 2.2
(2H, m, allyl).

H.L. Milton et al. / Polyhedron 23 (2004) 2575–2585
2585
4. Crystallography
Details of the structure determination are given in
Table 1. X-ray diffraction measurements were made
with graphite-monochromated Mo Ka X-radiation
using a Bruker SMART diffractometer. Intensity data
were collected using x// steps accumulating area
detector frames spanning a hemisphere of reciprocal
space for all structures. All data were corrected for
Lorentz, polarisation and long-term intensity fluctua-
tions. Absorption effects were corrected on the basis
of multiple equivalent reflections or by semi-empirical
methods. Structures were solved by direct methods
and refined by full-matrix least-squares against F2
(
SHELXTL). Hydrogen atoms were assigned isotropic
displacement parameters and were constrained to ide-
alised geometries. 8 gave Flack parameter of
a
0.01(3). Refinements converged to residuals given in
Table 1. All calculations were made with SHELXTL
[15].
5. Supplementary material
Atomic coordinates, thermal parameters and bond
lengths and angles have been deposited at the
Cambridge Crystallographic Data Centre (CCDC
Nos. 243091–243097). Any request to CCDC, 12 Un-
ion Road, Cambridge, CB2 1EZ, UK (fax: +44 1223
336033; e-mail: deposit@ccdc.cam.ac.uk; http://
www.ccdc.cam.ac.uk) for this material should
quote the full literature citation and the reference
number.
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