Late transition metal complexes of a new P-N ligand Ph2PCH2N(H)C5H3(Cl-5)N: Synthesis and structural studies

Article abstract of DOI:10.1039/b008502m

A new functionalised pyridylphosphine Ph₂PCH₂N(H)C₅H₃(Cl-5)N 1 has been synthesized from and Ph₂PCH₂OH and 2-H₂NC₅H₃(Cl-5)N. Reaction of 1 with aqueous H₂O₂ gave Ph₂P(O)CH₂N(H)C₅H₃(Cl-5)N 2. The crystal structures of 1 and 2 reveal, in both cases, dimer pair formation through N-H···N_pyridyl or N-H···OP intermolecular hydrogen bonding respectively. Chloro bridge cleavage of either [{RuCl(μ-Cl)(η⁶-p-MeC₆H₄ Prⁱ)}₂], [{RhCl(μ-Cl)(η⁵-C₅Me₅)}₂] or [{Pd(C₁₂H₁₂N)(μ-Cl)}₂] with two equivalents of 1 gave the mononuclear complexes [RuCl₂(η⁶-p-MeC₆H₄ Prⁱ)1] 3, [RhCl₂(η⁵-C₅Me₅)1] 4 or [PdCl(C₁₂H₁₂N)1] 5 (P trans to N) respectively. The chloro complexes [AuCl(1)] 6, [PtCl₂(1)₂] 7 and [PdCl₂(1)₂] 8 were prepared by substitution of tht (tetrahydrothiophene) (or cod) from [AuCl(tht)] or [MCl₂(cod)] (M = Pt or Pd). In 3-8 only P-ligation of 1 was observed. Chloride abstraction from either 3-5 or 7, 8 using Ag[BF₄] gave the cationic complexes [RuCl(η⁶-p-MeC₆H₄Prⁱ) {Ph₂PCH₂N(H)C₅H₃(Cl-5)N-P,N}] [BF₄] 9, [RhCl(η⁵-C₅Me₅){Ph₂ PCH₂N(H)C₅H₃(Cl-5)N-P,N}][BF₄] 10, [Pd(C₁₂H₁₂N){Ph₂PCH₂ N(H)C₅H₃(Cl-5)N-P,N}][BF₄] 11 and cis-[M{Ph₂PCH₂N(H)C₅H₃(Cl-5) N-P,N}₂][BF₄]₂ (M = Pt 12 or Pd 13) in which 1 chelates through both P and N_pyridyl donor atoms. All complexes were characterised by a combination of multinuclear NMR, IR spectroscopy and elemental analyses. Furthermore the crystal structures of 5-7 and 12 have been determined and reveal several types of N-H···X (X = N, F or Cl; inter- or intra-molecular) hydrogen bonding contacts. The structure of 12 represents an extremely rare, crystallographically characterised, M-P-C-N-C-N six-membered metallacyle.

Full text of DOI:10.1039/b008502m

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Late transition metal complexes of a new P–N ligand
Ph PCH N(H)C H (Cl-5)N: synthesis and structural studies
2
2
5 3
Simon J. Coles,a Sean E. Durran,b Michael B. Hursthouse,a Alexandra M. Z. Slawinc and
Martin B. Smith*b
a EPSRC X-Ray Crystallography Service, Department of Chemistry, University of Southampton,
HighÐeld, Southampton, UK SO17 1BJ
b Department of Chemistry, L oughborough University, L oughborough, L eics., UK L E11 3T U.
E-mail: m.b.smith=lboro.ac.uk; Fax: ]44 (0)1509 223925
c School of Chemistry, University of St. Andrews, St. Andrews, Fife, UK KY 16 9ST
Received (in Cambridge, UK) 19th October 2000, Accepted 19th December 2000
First published as an Advance Article on the web 22nd February 2001
A new functionalised pyridylphosphine Ph PCH N(H)C H (Cl-5)N 1 has been synthesized from Ph PCH OH and
2
2
5
3
2
2
2-H NC H (Cl-5)N. Reaction of 1 with aqueous H O gave Ph P(O)CH N(H)C H (Cl-5)N 2. The crystal
2
5
3
2
2
2
2
5
3
structures of 1 and 2 reveal, in both cases, dimer pair formation through NÈHÉ É ÉN
intermolecular hydrogen bonding respectively. Chloro bridge cleavage of either [MRuCl(l-Cl)(g6-p-MeC H Pri)N ],
or NÈHÉ É ÉOP
pyridyl
6
4
2
[MRhCl(l-Cl)(g5-C Me )N ] or [MPd(C
H
N)(l-Cl)N ] with two equivalents of 1 gave the mononuclear complexes
5
5 2
12 12
2
[RuCl (g6-p-MeC H Pri)1] 3, [RhCl (g5-C Me )1] 4 or [PdCl(C
H
N)1] 5 (P trans to N) respectively. The
2
6
4
2
2
5
5
12 12
chloro complexes [AuCl(1)] 6, [PtCl (1) ] 7 and [PdCl (1) ] 8 were prepared by substitution of tht
2
2
2
(tetrahydrothiophene) (or cod) from [AuCl(tht)] or [MCl (cod)] (M \ Pt or Pd). In 3È8 only P-ligation of 1 was
2
observed. Chloride abstraction from either 3È5 or 7, 8 using Ag[BF ] gave the cationic complexes [RuCl(g6-p-
4
MeC H Pri)MPh PCH N(H)C H (Cl-5)N-P,NN][BF ] 9, [RhCl(g5-C Me )MPh PCH N(H)C H (Cl-5)N-
6
4
2
2
5
3
4
3
5
5
2
2
5 3
P,NN][BF ] 10, [Pd(C
H N)MPh PCH N(H)C H (Cl-5)N-P,NN][BF ] 11 and cis-[MMPh PCH N(H)C H (Cl-
4
12 12
2
2
5
4
2
2
5 3
5)N-P,NN ][BF ] (M \ Pt 12 or Pd 13) in which 1 chelates through both P and N
donor atoms. All
2
4 2
pyridyl
complexes were characterised by a combination of multinuclear NMR, IR spectroscopy and elemental analyses.
Furthermore the crystal structures of 5È7 and 12 have been determined and reveal several types of NÈHÉ É ÉX
(X \ N, F or Cl; inter- or intra-molecular) hydrogen bonding contacts. The structure of 12 represents an extremely
rare, crystallographically characterised, MÈPÈCÈNÈCÈN six-membered metallacyle.
sation and a study of its ligation behaviour towards several
late transition-metal precursors. Some similarities in reactivity
Introduction
Pyridylphosphines continue to engender much interest as
excellent ligands for use in co-ordination and organometallic
chemistry.1,2 Their extreme versatility stems principally from
the ease of synthesis which can inÑuence dramatically ligand
and complex behaviour. One frequently encountered pyridyl-
phosphine is (2-C H N)PPh (dppy)3 which displays several
have previously been noted with Ph PCH NHC (H) N(OH)
2
2
5
3
and furthermore, the hydroxy group has been shown to
undergo further reactions.17 The incorporation of a suitably
disposed halogeno group o†ers, amongst others, two attrac-
tive possibilities: (i) further functionalisation and (ii) the
potential for hydrogen bonding or other secondary inter-
actions. The crystal structures of six compounds have been
determined and a propensity for intramolecular or intermolec-
ular hydrogen bonding is observed. The formation of dimer
pairs via NÈHÉ É ÉX (X \ N, O or Cl) is especially prevalent.
5
4
2
ligating modes to transition metals (e.g. P-co-ordination, P,N-
chelation and P,N-bridging). Recently there has been con-
siderable interest in the development of bidentate ligand
systems in which a pyridyl group may adopt exocyclic
positions4 with respect to the phosphorus centre or constitute
the spacer5,6 between two PR moieties. Examples of multi-
2
Experimental
functional P/N(pyridyl)/X (X \ N,7 O 8 or C 9) and even
chiral ligand systems in which the chirality can be located
either at P 10 or in the backbone11 have also been docu-
mented.
General
Standard Schlenk techniques were used for ligand syntheses
whilst all other reactions were carried out in air using pre-
viously distilled solvents unless otherwise stated. The ligand
Ph PCH OH was prepared from Ph PH and (CH O)
The co-ordination chemistry of pyridylphosphines is
diverse1 with several complexes Ðnding important catalytic
applications, most signiÐcantly the alkoxycarbonylation of
alkynes.12,13 The mechanism and aspects of the co-ordination
chemistry relevant to this process have been studied in detail
by the groups of Matteoli14 and Edwards.15 Recently the
hydrogenation of arenes using rhodium pyridylphosphine
complexes anchored to a silica-supported palladium hetero-
geneous catalyst was described.16 Herein we report the syn-
thesis of a new pyridylphosphine, prepared by simple conden-
2
2
2
2
n
according to a literature method18 as were the metal com-
plexes [MRuCl(l-Cl)(g6-p-MeC H Pri) N],19 [MRhCl(l-Cl)-
6
4
2
(g5-C Me )N ],20 [MPd(C
H
N)(l-Cl)N ],21 [AuCl(tht)]
5
5 2
12 12
2
(tht \ tetrahydrothiophene)22 and [MCl (cod)] (M \ Pd or
2
Pt; cod \ cycloocta-1,5-diene).23,24 All other chemicals were
obtained from commercial sources and used directly without
further puriÐcation.
416
New J. Chem., 2001, 25, 416È422
DOI: 10.1039/b008502m
This journal is ( The Royal Society of Chemistry and the Centre National de la Recherche ScientiÐque 2001

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Infrared spectra were recorded as KBr pellets in the range
4000È200 cm~1 on a Perkin-Elmer System 2000 Fourier-
transform spectrometer, 1H NMR spectra (250 MHz) on a
Bruker AC250 FT spectrometer with chemical shifts (d) in
(84%). IR: 3277 l , 1596 cm~1 l
; FAB MS: m/z 598
; FAB MS: m/z
NH
CN(pyridyl)
(M-Cl). IR: 3384 l , 1595 cm~1 l
NH
CN(pyridyl)
603 (M [ Cl).
ppm to high frequency of SiMe , 31P-M1HN NMR spectra on
[AuCl{Ph PCH N(H)C H (Cl-5)N} ], 6. To a CH Cl (10
4
2
2
5
3
2 2
a JEOL FX90Q (36.2 MHz) spectrometer with chemical shifts
mL) solution of [AuCl(tht)] (0.078 g, 0.243 mmol) was added
Ph PCH N(H)C H (Cl-5)N (0.078 g, 0.242 mmol) as a solid
(d) to high frequency of 85% H PO . All NMR spectra were
3
4
2
2
5 3
measured in CDCl unless otherwise stated. Elemental
in one portion. The solution was stirred for B15 min and
reduced in vacuo to ca. 1 mL. Addition of diethyl ether (15
mL) and light petroleum (bp 60È80 ¡C, 15 mL) gave a white
solid which was collected by suction Ðltration and dried in
3
analyses (Perkin-Elmer 2400 CHN Elemental Analyzer)
(Table 1) were performed by the Loughborough University
Analytical Service within the Department of Chemistry.
vacuo. Yield: 0.113 g, 84%. IR: 3242 l , 1597 l
, 323
NH
CN(pyridyl)
cm~1 l
. FAB MS: m/z 1083 (M [ Cl) (dimer pair).
Preparations
AuCl
2
[PtCl {Ph PCH N(H)C H (Cl-5)N} ], 7. To a CH Cl
Ph PCH N(H)C H (Cl-5)N, 1.
A
CH OH (15 mL)È
2
2
2
5
3
2
2 2
2
2
5
3
3
(10 mL) solution of [PtCl (cod)] (0.050 g, 0.134 mmol) was
toluene (25 mL) solution of Ph PCH OH (1.00 g, 4.62 mmol)
2
2
2
added Ph PCH N(H)C H (Cl-5)N (0.087 g, 0.266 mmol) to
and 2-amino-5-chloropyridine (0.595 g, 4.63 mmol) was heated
to B65 ¡C for ca. 6 d. The volume was reduced to B3È4 mL
whereupon a white solid deposited. The solid was collected by
2
2
5
3
give a colourless solution. After stirring for ca. 15 min the
volume was concentrated to 1È2 mL under reduced pressure
and Et O (20 mL) added. The mixture was stirred for 1 h,
suction Ðltration, washed with cold CH OH (5 mL) and dried
2
3
Ðltered under suction Ðltration and dried in vacuo overnight.
in vacuo. Additional crops of compound 1 could be isolated
Yield: 0.086 g, 70%. IR: 3373, 3319 l , 1596 l
, 310,
from the Ðltrate. Yield: 1.311 g, 87%. IR: 3219 l , 1593
NH
284 cm~1 l . FAB MS: m/z 883 (M [ Cl).
PtCl
CN(pyridyl)
NH
cm~1 l
. EI MS: m/z 326 (M`).
CN(pyridyl)
In a similar manner [PdCl MPh PCH N(H)C H (Cl-5)NN ]
2
2
2
5
3
2
8 was isolated in 85%. IR: 3371, 3306 l , 1596 l
,
Ph P(O)CH N(H)C H (Cl-5)N, 2. To a CH Cl (5 mL)
NH
CN(pyridyl)
2
2
2
5
3
2 2
306, 282 cm~1 l
. FAB MS: m/z 795 (M [ Cl).
solution of Ph PCH N(H)C H (Cl-5)N (0.094 g, 0.288 mmol)
PdCl
2
5 3
was added aqueous H O (30% w/w, B1 mL). After stirring
2
2
the two-phase system for 1 h, anhydrous MgSO was added
[RuCl(g6-p-MeC H Pri){Ph PCH N(H)C H (Cl-5)N-
4
and the MgSO removed by Ðltration. The solvent was evapo-
4
6
4
2
2
5 3
P,N} ] [BF ], 9. To a CH Cl (30 mL) suspension of Ag[BF ]
4
2
2
4
rated to dryness under reduced pressure and triturated with
(0.032 g, 0.164 mmol) was added [RuCl (g6-p-
MeC H Pri)MPh PCH N(H)C H (Cl-5)NN] (0.096 g, 0.152
mmol) and the mixture stirred in the dark for 2 h. The AgCl
was Ðltered o† through a small Celite plug and the orange
solution reduced in vacuo to ca. 1È2 mL. Addition of diethyl
ether (15 mL) gave compound 9 which was collected by
suction Ðltration, washed with diethyl ether (2 mL) and dried
2
diethyl ether (10 mL). The product was collected by suction
Ðltration and dried in vacuo. Yield: 0.058 g, 59%. IR: 3249
6
4
2
2
5 3
l
, 1596 l
, 1174 cm~1 l . EI MS: m/z 342 (M`).
NH
CN(pyridyl)
PO
Crystals of compound 2 suitable for X-ray crystallography
were obtained by slow evaporation of the Ðltrate from the
reaction of [Pd(OAc) ] with two equivalents of 1.
2
in vacuo. Yield: 0.096 g, 92%. IR: 3364 l , 1611 cm~1
NH
[RuCl (g6-p-MeC H Pri){Ph PCH N(H)C H (Cl-5)N} ],
l
. FAB MS: m/z 597 (M [ BF ).
2
6
4
2
2
5 3
CN(pyridyl)
4
3. To a CH Cl (20 mL) solution of [MRuCl(l-Cl)(g6-p-
In a similar manner the following complexes were pre-
2
2
MeC H Pri)N ] (0.100 g, 0.163 mmol) was added
pared: [RhCl(g5-C Me )MPh PCH N(H)C H (Cl-5)N-P,NN]-
6
4
2
5
5
2
2
5 3
Ph PCH N(H)C H (Cl-5)N (0.107 g, 0.328 mmol). The solu-
[BF ] 10 (77%) and [Pd(C
H
N)MPh PCH N(H)-
2
2
5 3
4
12 12
2
2
tion was stirred for B15 min, reduced in vacuo to ca. 1È2 mL
and diethyl ether (10 mL) added. The solid was collected by
suction Ðltration and dried in vacuo. Yield: 0.190 g, 92%. IR:
C H (Cl-5)N-P,NN][BF ] 11 (99%). IR: 3363 l , 1613 cm~1
5
3
4
NH
l
; FAB MS: m/z 599 (M [ BF ). IR: 3383 l , 1608
CN(pyridyl)
cm~1 l
4
NH
. FAB MS: m/z 603 (M [ BF ).
CN(pyridyl)
4
3252 l , 1595 cm~1 l
. FAB MS: m/z 634 (M`).
In a similar manner the following complexes were pre-
NH
CN(pyridyl)
cis-[Pt{Ph PCH N(H)C H (Cl-5)N-P,N} ] [BF ] ,
4 2
To a CH Cl (25 mL) suspension of Ag[BF ] (0.053 g, 0.272
12.
2
2
5
3
2
pared: [RhCl (g5-C Me )MPh PCH N(H)C H (Cl-5)NN]
4
2
5
5
2
2
2
5 3
5 3
2
2
4
(79%) and [PdCl(C
H N)MPh PCH N(H)C H (Cl-5)NN] 5
mmol) was added [PtCl MPh PCH N(H)C H (Cl-5)NN ]
12 12
2
2
2
2
5
3
2
(0.100 g, 0.109 mmol) and the mixture stirred in the dark for 2
h. The AgCl was Ðltered o† through a small Celite plug and
the yellow solution evaporated to dryness. The residue was
taken up in CH Cl (2 mL) and addition of diethyl ether (15
Table 1 Microanalytical data for compounds 1È13a
2
2
Analysis (%)
mL) gave a pale yellow solid which was collected by suction
Ðltration, washed with Et O and dried in vacuo. Yield: 0.078
Compound
C
H
N
2
g, 70%. IR: 3364 l , 1628, 1597 cm~1 l
. FAB
similar manner
NH
CN(pyridyl)
1
2
3
65.64(66.15)
63.00(63.07)
52.41(53.12)
51.95(52.15)
56.26(56.39)
38.79(38.66)
47.46(47.02)
51.85(52.04)
48.71(49.14)
47.28(47.09)
50.28(50.23)
42.36(42.30)
46.36(46.32)
4.76(4.95)
4.70(4.71)
4.87(4.79)
4.69(5.01)
4.48(4.43)
2.94(2.88)
3.78(3.51)
3.91(3.88)
4.50(4.43)
4.49(4.81)
3.94(4.37)
3.17(3.16)
3.65(3.46)
8.37(8.57)
7.89(8.17)
4.65(4.43)
4.30(4.35)
6.41(6.58)
4.85(5.01)
5.84(6.09)
6.43(6.74)
3.73(4.09)
3.69(3.92)
5.58(5.86)
5.38(5.48)
5.08(6.00)
MS: m/z 935 (M [ BF ). In
a
4
[PdMPh PCH N(H)C H (Cl-5)N-P,NN ][BF ] 13 was iso-
2
2
5
3
2
4 2
lated in 55% yield. IR: 3350 l , 1623 cm~1 l
. FAB
4b
5
NH
CN(pyridyl)
MS: m/z 760 (M [ 2BF ).
4
6
7
X-Ray crystallography
8
9
Crystals of compounds 1, 6 and 7 suitable for X-ray crystal-
lography were grown by slow di†usion of diethyl ether into a
10c
11c
12
13
CDCl solution over several days. For 5 crystals were grown
3
by slow di†usion of diethyl etherÈlight petroleum (bp 60È
80 ¡C) into a CDCl solution over several days whilst in the
a Calculated values in parentheses. b Contains 0.5H O. c Contains
3
2
case of 12 crystals were grown by vapour di†usion of diethyl
1.5H O.
2
ether into a CH Cl ÈCH OH solution over several days.
2
2
3
New J. Chem., 2001, 25, 416È422
417

View Article Online
The crystal structures of compounds 1, 2 and 5È7 were
obtained using either a Bruker SMART di†ractometer with
graphite-monochromated (Mo-Ka) radiation (j \ 0.710 37 A)
or a Rigaku AFC7S serial di†ractometer with graphite-
monochromated Cu-Ka radiation (j \ 1.541 78 A) and u
scans. Details of the crystal data collection and reÐnement are
given in Table 3. All data were corrected for Lorentz-
polarisation and long-term intensity Ñuctuations. Absorption
e†ects were corrected on the basis of multiple equivalent
reÑections or by empirical methods.25 Structures were solved
by direct methods and reÐned by full-matrix least squares
against
F (TEXSAN26) for data with I [ 2p(I) or F2
(SHELXTL27) for all data. A standard SHELXTL weighting
scheme was used for 1 and 7 whilst in the case of 2, 5 and 6
the weighting scheme for the Rigaku/TEXSAN was as pre-
viously reported.28 All NÈH protons were located (0.98 A in 1,
7; 1.00 A in 2, 5 and 6). ReÐnements converged to residuals
given in Table 3. All calculations were made with programs
from the SHELXTL or TEXSAN systems.
For compound 12 data were collected on a colourless plate
on a Nonius Kappa CCD area detector di†ractometer at the
window of a rotating anode FR591 generator, with a molyb-
denum target [j(Mo-Ka) \ 0.710 69 A] and controlled by the
COLLECT29 software package. Data were corrected for
absorption using the empirical method employed in Sortav.30
The structure was solved by direct methods (SHELXS 9731)
and then subjected to full-matrix least squares reÐnement
Scheme 1 (i) H NC H N(Cl-5), (ii) aq. H O .
2
5
3
2 2
H NC H N(Cl-5) for ca. 6 d (Scheme 1). The 31P-M1HN NMR
2
5 3
spectrum of 1 (Table 2 and for other characterisation data see
Experimental) showed a single phosphorus resonance at d(P)
[17.4, an identical shift to that of the unsubstituted ligand
Ph PCH N(H)C H N.17 Further conÐrmation for the pres-
2
2
5 4
ence of only one ““Ph PCH ÏÏ group [as opposed to
2
2
(Ph PCH ) NC H N(Cl-5)
bearing
two
““Ph PCH ÏÏ
2
2 2
5
3
2
2
moieties] came from the 1H NMR and IR spectra which
showed a broad d(NH) resonance at 4.71 and a sharp l
NH
vibration at 3219 cm~1 respectively. In the crystal structure of
1 (Fig. 1, Table 4) molecules of Ph PCH N(H)C H N(Cl-5)
2
2
5 3
are arranged in dimer pairs by intermolecular NÈHÉ É ÉN
based on F2 (SHELXL 9731). Non-hydrogen atoms were
pyridyl
o
hydrogen bonds [N(14)É É ÉN(16A) 3.10(1), H(14n)É É ÉN(16A)
2.12 A; N(14)ÈH(14n)É É ÉN(16A) 175¡]. A similar observation
was recently noted by Woollins and co-workers for
Ph PN(H)C H N.2a
reÐned anisotropically with hydrogens included in idealised
positions (CÈH distance 0.97 A) with thermal parameters
riding on those of the parent atom. The presence of the NÈH
protons was conÐrmed in the di†erence map, however they
were included in the model in calculated positions, riding on
the coordinates of the parent atom.
2
5 4
Oxidation of compound
1 with aqueous H O gave
2
2
Ph P(O)CH N(H)C H N(Cl-5) 2 in 59% yield (Scheme 1).
2
2
5 3
The downÐeld shift in d(P) (29.7) and the observation of an
CCDC reference number 440/253. See http://www.rsc.org/
suppdata/nj/b008502m/ for crystallographic Ðles in .cif format.
intense l absorption at 1174 cm~1 are in accord with oxida-
PO
tion of the phosphorus(III) centre. The crystal structure of 2
(Fig. 2, Table 4) has been determined and conÐrms a tertiary
phosphine oxide with a PO bond length of 1.489(2) A consis-
tent with appreciable double bond character.32 Molecules of
Ph P(O)CH N(H)C H N(Cl-5) are linked into dimer pairs
Results and discussion
We recently reported the synthesis of some new, potentially
multidentate, pyridylphosphines Ph PCH N(H)C H N(OX)
2
2
5 3
through intermolecular NÈHÉ É ÉOP hydrogen bonding
[N(14)É É ÉO(1A) 2.89(1), H(14n)É É ÉO(1A) 1.93 A; N(14)È
H(14n)É É ÉO(1A) 153¡] forming a pseudo ten-membered ring.
Previously NHÉ É ÉOP hydrogen-bonding has been observed
in the mixed PIII/PV ligand Ph PN(H)P(O)Ph 33
2
2
5 3
[X \ H, PPh , P(O)Ph or P(O)(OPh) ] and demonstrated
2
2
2
various co-ordination capabilities of these ligands.17 The syn-
thesis of the new 5-chloro substituted ligand
Ph PCH N(H)C H N(Cl-5) 1 was readily accomplished by
2
2
5
3
2
2
heating a CH OHÈtoluene solution of Ph PCH OH and
and the unusual platinum(II) complexes [PtMP(O)(OMe)-
3
2
2
Table 2 Selected 31P and 1H NMR data for compounds 1È13
d(H)
Compound
d(P)
1J(PtP)
1J(RhP)
arom.
NH
CH
2
1
2
[17.4
29.7
19.0
24.5
38.7
27.5
7.7
8.05È6.34
8.00È6.39
7.90È5.97
7.88È6.11
8.10È6.23
8.00È6.42
7.90È6.48
8.22È6.57
8.90È7.20
8.29È7.14
8.08È6.57
4.71
5.25
5.58
6.11
4.05
4.37
4.74a
4.84b
4.75c
4.65
4.64
4.80e
3
4
145
5
6
4.88
5.80
7
3682
8
29.7, 15.4d
9
33.7
25.4
33.4
2.0
3.09, 4.68a
3.68, 4.51b
4.24c
10
11
12
13
141
3532f
29.1g
a iPrC H Me resonances at d 5.28È5.19, 2.57, 1.88 and 0.95 (for 3); 5.52È4.92, 2.01, 1.05 and 1.01 (for 9). b C Me resonance at d 1.38 [J(PH) 3.5
6
4
5
5
Hz] (for 4); 1.38 [J(PH) 3.5 Hz] (for 10). c NMe resonance at: d 3.55 (for 5); 3.15 [J(PH) 2.1 Hz] (for 11). d Ca. 2.5 : 1 ratio of cis : trans isomers
2
respectively in CDCl , ca. 17 : 1 ratio in (CD ) SO. e Recorded in (CD ) SO. f Recorded in CDCl ÈCH OH. g Recorded in CH Cl ÈC D .
3
3 2
3 2
3
3
2
2
6 6
418
New J. Chem., 2001, 25, 416È422

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Table 3 Details of the X-ray data collections and reÐnements for compounds 1, 2, 5È7 and 12
1
2
5
6
7
12
Empirical formula
C
326.75
Monoclinic
P2 /c
13.3340(12)
5.8545(5)
21.617(2)
H
ClN P
C
342.76
Triclinic
P1
9.226(2)
12.365(6)
8.559(4)
98.90(4)
107.85(2)
106.17(3)
861.3(6)
293
H
ClN OP
C
638.85
Monoclinic
P2 /c
11.944(3)
14.623(2)
16.140(2)
H
Cl N PPd
C
559.18
Triclinic
P1
9.849(3)
11.647(3)
9.054(2)
109.31(2)
95.75(3)
102.41(3)
940.6(5)
293
H
AuClN P
C
H
Cl N P Pt
C
H
B Cl F N P Pt
18 16
2
18 16
2
30 28
2
3
18 16
2
36 32
4
4
2
36 32
2
2
8
4
2
M
919.49
Triclinic
P1
11.3466(2)
11.5291(2)
16.0391(3)
65.574(1)
89.056(1)
69.75
1831.71(6)
293(2)
2
4.24
9342
1022.21
Monoclinic
P2 /c
12.8214(1)
18.0482(2)
17.5951(2)
Crystal system
Space group
1
1
1
a/A
b/A
c/A
a/¡
b/¡
c/¡
90.761(2)
91.36(2)
93.954(1)
U/A
Ž
3
1687.3(3)
293(2)
4
0.319
6101
2818.1(9)
293
4
0.92
5437
4061.87(7)
150(2)
4
3.73
45 264
9139(0.0668)
T /K
Z
2
0.32
3229
3025(0.015)
2
8.17
3514
3306(0.029)
k/mm~1
Measured reÑections
Independent reÑections
2325(0.2699)
5175(0.049)
5209(0.0279)
4587
(R
)
int
Observed reÑections
1695
2160
2869
2436
9139
(I [ 2.0p(I))
Final R, R
0.088, 0.166
0.034, 0.033
0.037, 0.048
0.026, 0.025
0.026, 0.062
0.043, 0.118
w
N(H)C(Ph)2NN(H)MeN(Cl)(PEt )] and [PtMP(O)(OMe)N(H)-
CH Cl gave the mononuclear complexes [RuCl (g6-p-
3
2
2
2
or [PdCl-
N(Me)C(Me)2NHN(Cl)(PEt )].34
MeC H Pri)(1)] 3, [RhCl (g5-C Me )(1)]
4
3
6
4
2
5
5
(C
H
N)(1)] 5 respectively (Scheme 2). Pertinent spectro-
12 12
scopic data are given in Table 2 and the Experimental. In all
P-Co-ordination studies
cases P-complexation was inferred by a downÐeld shift in d(P)
A brief study of the ligating ability of compound 1 was under-
taken to ascertain the potential for P-co-ordination and
P,N
-chelation. First halogeno-bridge cleavage of either
pyridyl
[MRuCl(l-Cl)(g6-p-MeC H Pri)], [MRhCl(l-Cl)(g5-C Me )N ]
or [MPd(C
6
4
2
5
5 2
H
N)(l-Cl)N ] with two equivalents, of 1 in
12 12
Fig. 2 Crystal structure of compound 2 showing the hydrogen
bonded dimer pair.
Fig. 1 Crystal structure of compound 1 showing the hydrogen
bonded dimer pair.
Table 4 Selected bond distances (A) and angles (¡) for compounds 1
and 2
1
2
P(1)ÈC(1)
1.826(4)
1.837(4)
1.840(5)
1.462(5)
1.363(5)
1.800(2)
1.792(2)
1.811(2)
1.443(3)
1.364(3)
1.489(2)
P(1)ÈC(7)
P(1)ÈC(13)
C(13)ÈN(14)
N(14)ÈC(15)
P(1)ÈO(1)
C(1)ÈP(1)ÈC(7)
102.1(2)
102.1(2)
97.6(2)
111.6(3)
121.7(4)
107.3(1)
105.3(1)
106.8(1)
111.3(2)
122.2(2)
112.6(1)
C(1)ÈP(1)ÈC(13)
C(7)ÈP(1)ÈC(13)
P(1)ÈC(13)ÈN(14)
C(13)ÈN(14)ÈC(15)
O(1)ÈP(1)ÈC(13)
Scheme 2 (i) [MRuCl(l-Cl)(g6-p-MeC H Pri) N], (ii) [MRhCl(l-Cl)(g5-
6
4
2
C Me )N ], (iii) [MPd(C
H
N)(l-Cl)N ], (iv) [AuCl(tht)], (v)
5
5
2
12 12
2
[PtCl (cod)], (vi) [PdCl (cod)]. R \ CH N(H)C H (Cl-5)N.
2
2
2
5 3
New J. Chem., 2001, 25, 416È422
419

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and further corroborated by very small changes in l
the tertiary phosphine ligands. In contrast complex 8 displays
two singlets at d(P) 29.7 and 15.4 consistent with both cis and
CN(pyridyl)
(from IR) indicating a non-co-ordinated pyridyl ring. The 1H
NMR spectra showed the expected resonances for co-
ordinated 1 in addition to the other spectator ligands. The
trans isomers35 present in CDCl solution (ca. 2.5 : 1 ratio
3
respectively). The ratio of these two isomers does not change
CH group was observed typically at ca. d(H) 4.80, some 0.75
signiÐcantly (ca. 3.5 : 1) even after allowing solutions to stand
for 6 d. In the solid state the IR spectrum indicated only the
2
ppm downÐeld from that of non-complexed 1. The crystal
structure of 5 (Fig. 3, Table 5) shows an orthometallated
cis isomer is present (l
306, 282 cm~1). The crystal struc-
PdCl
C
H
N, Cl~ and Ph PCH N(H)C H N(Cl-5) ligands
tures of 6 and 7 have both been determined. For 6 (Fig. 4,
Table 5), the expected linear geometry is observed [Cl(1)È
Au(1)ÈP(1) 174.96(7)¡] and, reminiscent of the structure of 1,
12 12
2
2
5 3
arranged in a cis disposition [i.e. P(1) trans to N(28)]. The
geometry around the palladium(II) centre is essentially square-
planar with bond angles in the range 83.3(2) [N(28)ÈPd(1)È
C(21)] to 94.1(2)¡ [P(1)ÈPd(1)-C(21)]. The PdÈN, PdÈP and
PdÈCl bond distances are unexceptional. Unlike the intermo-
lecular hydrogen-bonding pattern observed in 1 and 2, the
amine proton of the co-ordinated ligand in 5 is intramolecu-
larly hydrogen bonded to an adjacent chloride [N(14)É É ÉCl(1)
3.18(1), H(14n)É É ÉCl(1) 2.60 A; N(14)ÈH(14n)É É ÉCl(1) 119¡].
forms a dimer pair arrangement through NÈHÉ É ÉN
hydrogen bonding [N(14)É É ÉN(16A) 3.07(1), H(14n)É É ÉN(16A)
pyridyl
2.14 A; N(14)ÈH(14n)É É ÉN(16A) 167¡]. No other secondary
interactions (i.e. AuÉ É ÉAu, ClÉ É ÉCl) are observed between mol-
ecules of 6. In contrast [AuClMPh PN(H)C H NN] forms an
2
5 4
inÐnite 1-D chain through NÈHÉ É ÉN
hydrogen bonding2a
pyridyl
and shows that by incorporating a methylene spacer between
the Ph P and N(H)C H N groups the gross solid state struc-
Reaction of [AuCl(tht)] or [MCl (cod)] (M \ Pt or Pd)
2
2
5 4
with one (or two) equivalent of 1 gave the chloro complexes
ture can be strongly inÑuenced. The platinum complex 7 (Fig.
5, Table 5) shows a near square-planar geometry [P(1)ÈPt(1)È
Cl(2) 87.23(5), Cl(1)ÈPt(1)ÈCl(2) 87.69(5), P(2)ÈPt(1)ÈCl(1)
88.92(5) and P(1)ÈPt(1)ÈP(2) 96.72(4)¡] with two cis bonded
Ph PCH N(H)C H N(Cl-5) and Cl~ ligands. The Pt lies 0.05
[AuCl(1)] 6, [PtCl (1) ] 7 and [PdCl (1) ] 8 respectively
2
2
2
2
(Scheme 2). In the case of 7, the 31P-M1HN NMR spectrum
(Table 2) showed a single 31P resonance Ñanked by 195Pt
satellites [1J(PtP) 3682 Hz] indicative of the cis disposition of
2
2
5 3
A below the plane of its four donor substituents. The PtÈP
and PtÈCl bond distances are normal and compare well with
those of cis-[PtCl (Ph PCH OH) ].36 Molecules of 7 are
2
2
2
2
arranged into dimer pairs via NÈHÉ É ÉCl
hydrogen
coord
bonding [N(14)É É ÉCl(1A) 3.39(1), H(14n)É É ÉCl(1A) 2.52 A;
N(14)ÈH(14n)É É ÉCl(1A) 147¡; [N(34)É É ÉCl(2A) 3.64(1),
H(34n)É É ÉCl(2A) 2.76 A; N(34)ÈH(34n)É É ÉCl(2A) 151¡]. This is
Fig. 3 Crystal structure of compound 5.
Table 5 Selected bond distances (A) and angles (¡) for compounds
5È7
5
6
7
Pd(1)ÈCl(1)
Pd(1)ÈP(1)
Pd(1)ÈN(28)
Pd(1)ÈC(21)
2.406(2)
2.250(2)
2.153(5)
2.009(6)
Fig. 4 Crystal structure of compound 6 showing the hydrogen
bonded dimer pair.
N(28)ÈPd(1)ÈC(21)
Cl(1)ÈPd(1)ÈN(28)
Cl(1)ÈPd(1)ÈP(1)
P(1)ÈPd(1)ÈC(21)
Cl(1)ÈPd(1)ÈC(21)
P(1)ÈPd(1)ÈN(28)
83.3(2)
91.2(1)
92.15(6)
94.1(2)
171.4(2)
173.2(1)
Au(1)ÈCl(1)
Au(1)ÈP(1)
2.294(2)
2.231(2)
Cl(1)ÈAu(1)ÈP(1)
174.96(7)
Pt(1)ÈCl(1)
Pt(1)ÈCl(2)
Pt(1)ÈP(1)
Pt(1)ÈP(2)
2.3500(13)
2.3594(13)
2.2572(12)
2.2494(12)
Cl(2)ÈPt(1)ÈP(1)
Cl(1)ÈPt(1)ÈCl(2)
Cl(1)ÈPt(1)ÈP(2)
P(1)ÈPt(1)ÈP(2)
Cl(1)ÈPt(1)ÈP(1)
Cl(2)ÈPt(1)ÈP(2)
87.23(5)
87.69(5)
88.92(5)
96.72(4)
169.90(4)
174.75(5)
Fig. 5 Crystal structure of compound 7 showing the hydrogen
bonded dimer pair.
420
New J. Chem., 2001, 25, 416È422

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further corroborated by two well resolved NÈH vibrations
(3373, 3319 cm~1) in the IR spectrum of 7.
P,N-Co-ordination studies
When a CDCl solution of 3 is allowed to stand for ca. 4 d a
3
new phosphorus-containing species 9 [d(P) 33.7] is formed,
whose 31PM1HN NMR shift is similar to that of [RuCl(g6-p-
MeC H Pri)MPh PCH N(H)C H N(OH)-P,NN]Cl
[d(P)
6
4
2
2
5 3
31.6].17 Hence we assign 9 as the isomerised cationic com-
plex [RuCl(g6-p-MeC H Pri)MPh PCH N(H)C H N(Cl-5)-
6
4
2
2
5 3
P,NN]Cl. Alternatively reaction of 3, 4 or 5 with approx-
imately one equivalent of Ag[BF ] in CH Cl for 2 h gave
4
2 2
5
the cationic complexes 9, [RhCl(g5-C Me )MPh PCH N(H)-
5
2
2
C H N(Cl-5)-P,NN][BF ]
10
and
[Pd(C
H
N)-
5
3
2
4
12 12
MPh PCH N(H)C H N(Cl-5)-P,NN[BF ]11astheirtetraÑuoro-
2
5
3
4
borate salts (Scheme 3). The 31P-M1HN NMR spectra show
small downÐeld shifts [d(P) 25.4, 1J(RhP) 141 Hz for 10; d(P)
33.4 for 11] with respect to those found for 4 and 5. Further
diagnostic conÐrmation for P,N
-chelation is seen in
pyridyl
(i) the 1H NMR spectra of 9È11 which show, in general, a
downÐeld shift for H(6). (This feature has previously been
documented for other complexes containing pyridylphos-
phines37), (ii) a shift to higher wavenumber for the pyridine
ring vibration (ca. 1610 cm~1).
Fig. 6 Crystal structure of compound 12 ([BF ]~ counter ion
4
omitted for clairty).
whilst the PtÈN bond lengths are comparable with those of
other platinum pyridylphosphine complexes.2c,38 The plane
deÐned by Pt and the co-ordinated P atoms makes a dihedral
(1)
angle of 17.65(11)¡ with the PtN mean plane. The PtÈPÈCÈ
2
NÈCÈN rings both adopt non-planar conformations presum-
ably arising from steric and pÈp interactions between the
phenyl groups on the phosphorus atoms which forces these
atoms out of the ring plane. There is an additional short NÈ
Reaction of compound 7 (or 8) with approximately two
equivalents, of Ag[BF ] in CH Cl gave the bis cationic com-
HÉ É ÉF intermolecular hydrogen bond with a [BF ]~ counter
4
2 2
4
plexes [MMPh PCH N(H)C H N(Cl-5)-P,NN ][BF ]
12
ion [N(3)É É ÉF(8) 2.87(1), H(3n)É É ÉF(8) 2.01 A; N(3)È
2
2
5
3
2
4 2
(M \ Pt) and 13 (M \ Pd) (Eqn. 1). The 31P-M1HN NMR
spectrum of 12 showed a marginal shift in d(P) (ca. 5 ppm) and
a reduction in 1J(PtP) of ca. 150 Hz (with respect to 7) upon
chelation through both P and N
pyridyl
further supported by the absence of l
tentative assignment of a ring stretching vibration of the co-
ordinated pyridyl group at 1623 cm~1. The crystal structure
of 12 (Fig. 6, Table 6) establishes a near square-planar
environment around Pt with two cis P,N-chelating
Ph PCH N(H)C H N(Cl-5) ligands. The PtÈP bond distances
H(3n)É É ÉF(8) 172¡]. The structure of 12 represents an
extremely rare crystallographically characterised six-
membered MÈPÈCÈNÈCÈN metallacycle.17,39 To date, the
only other crystal structure containing this fragment is the
donor atoms. This was
vibrations and the
cationic complex
workers.39
A reported by Schmidbaur and co-
PtCl
2
2
5 3
are similar to those seen in 7 [2.2572(12) and 2.2494(12) A]
In conclusion, we have shown that a new pyridylphosphine
ligand is readily accessible and undergoes complexation to a
range of late transition metals (Ru, Rh, Pd, Pt and Au). Fur-
thermore both P- and P,N
-bonding modes have been
pyridyl
observed and veriÐed by spectroscopic and X-ray crystallo-
graphic studies. The crystal structures of several examples
have been determined and illustrate a range of intra- and
Table 6 Selected bond distances (A) and angles (¡) for compound 12
Pt(1)ÈP(1)
Pt(1)ÈP(2)
2.2283(11)
2.2321(10)
Pt(1)ÈN(2)
Pt(1)ÈN(4)
2.140(4)
2.127(4)
P(2)ÈPt(1)ÈN(4)
P(1)ÈPt(1)ÈN(2)
N(2)ÈPt(1)ÈN(4)
85.14(10)
88.74(11)
90.15(14)
P(1)ÈPt(1)ÈP(2)
P(1)ÈPt(1)ÈN(4)
P(2)ÈPt(1)ÈN(2)
98.83(4)
165.83(11)
166.69(9)
Scheme 3 (i) Ag[BF ], CH Cl .
4
2 2
New J. Chem., 2001, 25, 416È422
421

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F. A. Cotton, G. L. Powell, S. M. Tetrick and R. A. Walton, J.
Am. Chem. Soc., 1984, 106, 1323.
inter-molecular hydrogen-bonding contacts (NÈHÉ É ÉX where
X \ N, O, F or Cl). The chloro (and other halogeno) deriv-
atives should serve as useful starting materials for further
functionalisation and work along these lines is currently under
investigation.
10 H. Yang, N. Lugan and R. Mathieu, Organometallics, 1997, 16,
2089.
11 G. He, S.-K. Loh, J. J. Vittal, K. F. Mok and P.-H. Leung,
Organometallics, 1998, 17, 3931; Q. Jiang, D. Van Plew, S.
Murtuza and X. Zhang, T etrahedron L ett., 1996, 37, 797; S. Stoc-
coro, G. Chelucci, A. Zucca, M. A. Cinellu, G. Minghetti and M.
Manassero, J. Chem. Soc., Dalton T rans., 1996, 1295.
12 R. J. van Haaren, C. J. M. Druijven, G. P. F. van Strijdonck, H.
Oevering, J. N. H. Reek, P. C. J. Kamer and P. W. N. M. van
Leeuwen, J. Chem. Soc., Dalton T rans., 2000, 1594; G. Francio,
R. Scopelliti, C. G. Arena, G. Bruno, D. Drommi and F. Faraone,
Organometallics, 1998, 17, 338; A. Caballero, F. A. Jalon and
B. R. Manzano, Chem. Commun., 1998, 1879; M. C. Bonnet, F.
Dahan, A. Ecke, W. Keim, R. P. Schulz and I. Thatchenko, J.
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Acknowledgements
We would like to thank the EPSRC for support. The EPSRC
Mass Spectrometery Service Centre at Swansea are also grate-
fully acknowledged. Precious metal salts were provided on
loan by Johnson Matthey plc.
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