Bis(phosphinomethyl)phenylamines and bis(phosphinomethyl)sulfides and their reaction with d8-platinum group precursors

Article abstract of DOI:10.1016/j.poly.2012.07.083

The potentially tridentate phosphines R₂PCH₂XCH ₂PR₂ [X = NPh, R = Ph (1), ^tBu (2), Cy (3), X = S, R = Ph (4), ^tBu (5)] were treated with different Pd(II), Pt(II) as well as Rh(I) and Ir(I)

Full text of DOI:10.1016/j.poly.2012.07.083

Polyhedron 46 (2012) 95–104
Contents lists available at SciVerse ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Bis(phosphinomethyl)phenylamines and bis(phosphinomethyl)sulfides and their
reaction with d8-platinum group precursors
⇑
Marc Stickel, Caecilia Maichle-Moessmer, Lars Wesemann, Hermann A. Mayer
Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
a r t i c l e i n f o
a b s t r a c t
t
Article history:
The potentially tridentate phosphines R2PCH2XCH2PR2 [X = NPh, R = Ph (1), Bu (2), Cy (3), X = S, R = Ph
(4), tBu (5)] were treated with different Pd(II), Pt(II) as well as Rh(I) and Ir(I) complex precursors. All
new palladium and platinum compounds are formed as cis bisphosphine complexes. This is also the case
if the sterically demanding phosphines 2 and 3 are treated with MCl(CO)(PPh3)2 while the comparable
reaction with 1 generates trigonal bipyramidal complexes. In contrast to this the reaction of 5 with
Ir(CO)2Cl(p-TolNH2) forms the macrocycle 5b. All new compounds have been characterized by 1H, 13C,
31P NMR and IR spectroscopy. Single crystal X-ray analysis has been performed from most of the com-
pounds as well.
Received 26 May 2012
Accepted 30 July 2012
Available online 5 August 2012
Dedicated to Alfred Werner on the 100th
Anniversary of his Nobel Prize in Chemistry
in 1913.
Ó 2012 Elsevier Ltd. All rights reserved.
Keywords:
Tridentate ligands
Bridging ligands
Chelating phosphines
Macrocyclic metal complexes
Platinum group metals
1. Introduction
potential use of their photophysical properties [14,15]. In this con-
text ligand systems of the type R2P(CH2)nX(CH2)nPR2 (X = NR0, PR0,
Polydentate ligands composed with phosphorus, nitrogen and
sulfur donors are popular building units to construct metal com-
plexes for a variety of purposes [1–4]. Depending on the combina-
tion of the ligand backbone, the donors and the metal as well as
further participating ligands, the resulting metal complexes offer
different chemical and physical properties [5–7]. Polydentate phos-
phines can act as both chelating ligands coordinating to one metal
and as bridging units connecting two and more [8,9]. Interestingly,
the bridging mode of the polyphosphines generates macrocyclic
systems [9]. In the case of bisphosphines this depends on the design
of the ligand backbone and the nature of the central metal atom
applied for coordination. For thermodynamic reasons chelation is
favored if five- and six-membered rings are formed whereas the
bridging mode is preferred if the ring size becomes larger than se-
ven. Chelation as well as the bridging mode is observed for ligands
which compose four-membered rings or eight-membered macro-
cycles [8,10]. The formation of chelates or macrocycles is also deter-
mined by the steric demand of the substituents at the phosphorus
side [8]. Here sterically crowded substituents prefer trans coordina-
tion which is in turn favored by macrocycles.
AsR0, S; R0= iPr, tBu, Ph; n = 1, 2) proved to be useful building blocks
[11–16]. The methylene groups function as spacers between the
donor centers, potentially allowing the formation of mono-, bi-
or trinuclear complexes [17]. Ligands with two methylene spacers
between the donor centers form monometallic complexes which
turned out to be catalytically active in olefin oligomerization as
well as Heck coupling reactions [11,18].
The potentially tridentate ligand R2PCH2XCH2PR2 (X = AsPh,
PPh) contains only one methylene group as spacer. Balch and co-
workers synthesized dinuclear metallamacrocycles by reaction of
bis(diphenylphosphinomethyl)phenylphosphine (dpmp) [19,20]
or bis(diphenylphosphinomethyl)phenylarsine (dpma) [15] with
iridium(I) or rhodium(I) precursors. The resulting diirida- and
dirhodacomplexes with dpmp or dpma allow the binding of a third
metal ion in the macrocyclic cavity leading to trinuclear ionic com-
plexes [15,21,22]. Of special interest are the photophysical proper-
ties e.g. the luminescence which is observed by some of these
arsenic trinuclear species [15]. Hiraki et al. reported on the gener-
ation of the corresponding dirhodamacrocyclic systems by reacting
the sulfur containing ligand bis(diphenylphosphinomethyl)sulfide
Bi- and trinuclear complexes of the platinum group have been
extensively studied both as catalytic systems [11–13] and for the
(dpms) with a half mol of [Rh2(l-Cl)2(CO)4] [23]. These systems
also are able to embed a third metal ion and metal ion fragments,
respectively [23]. In contrast to this the reaction of dpms with
Na2[PdCl4] leads to the formation of a monometallic cis-complex.
Balch and co-workers were the first to report a monometallic
⇑
Corresponding author.
E-mail address: hermann.mayer@uni-tuebingen.de (H.A. Mayer).
0277-5387/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.poly.2012.07.083

96
M. Stickel et al. / Polyhedron 46 (2012) 95–104
palladium(II) complex with bis(diphenylphosphinomethyl)phenyl-
amine (dpmpa) [17].
We focused our interest on the potentially tridentate ligands
R2PCH2XCH2PR2 (X = NPh, R = Cy, Ph, tBu; X = S, R = Ph, tBu)
[17,23–25] with nitrogen and sulfur, respectively, as additional do-
nors and their complexation behavior with platinum group metals.
80 °C for 3 h. All the solvent except for 1 ml was removed. The yel-
low suspension was treated with ether to fully precipitate the
product which was collected by filtration, washed with diethylether
and n-pentane and dried in vacuo. Yield: 67 mg (79%). IR (KBr, cmꢀ1):
2
1932
m
(CO). 31P{1H} NMR (CDCl3), d: ꢀ30.0 (t, JPP = 34.0, ꢀ60 °C),
ꢀ37.8 (t, JPP = 34.0, ꢀ60 °C). 1H NMR (CDCl3), d: 4.07 (br. m, 8H,
2
3
3
CH2P), 6.28 (d, JHH = 7.5 Hz, 4H, o-CH, NPh), 6.99 (t, JHH = 7.3 Hz,
2H, p-CH, NPh), 7.14 (m, 4H, m-CH, NPh), 6.4–7.7 (br. m, 40H,
PPh). 13C{1H} NMR (CDCl3), d: 48.4 (br. s, CH2P), 61.6 (br. s, CH2P),
121.3 (s, o-C, NPh), 128.2 (s, p-C, NPh), 130.0 (s, m-C, NPh), 154.6
(m, ipso-C, NPh). 128.2–136.1 (m, PPh) ESI–MS (m/z): 1199.2
[MꢀCl]+; 1171.2 [MꢀClꢀCO]+. Anal. Calc. for C65H58ClIrN2OP4: C,
63.23, H, 4.73, N, 2.27. Found C, 63.48, H, 4.90, N, 1.88%.
2. Experimental
All syntheses were carried out under an atmosphere of Argon
(99.999% purity) unless noted otherwise. Dry solvents were ob-
tained from the solvent purification system SPS-800 by MBRAUN.
Methanol was dried over magnesium. Pd(PhCN)2Cl2, Pt(PhCN)2Cl2,
CODPtCl2, CODPtBr2, di-tert-butylphosphine and diphenylphos-
phine were purchased from ABCR Chemical Company. Tetra-
carbonyldichlorodirhodium was obtained from Sigma Aldrich
Chemical Company. NMR spectra were measured on a Bruker
DRX-250 NMR spectrometer equipped with a 5 mm ATM probe
head operating at 250.13 MHz (1H), 101.25 MHz (31P), a Bruker
DRX-400 NMR spectrometer equipped with a 5 mm QNP (quad nu-
cleus) probe head operating at 400.13 MHz (1H), 100.13 MHz (13C),
2.3. Synthesis of [Pd(CN)2{PhN(CH2PPh2)2}] (1c00)
A solution of 77 mg (0.12 mmol) of 1c and 40 mg (0.8 mmol) of
NaCN dissolved in 20 ml of MeOH was stirred for 2 h at rt. Removal
of the solvent gave a white powder which was washed successively
with methanol (1 ꢂ 5 ml) and diethylether (2 ꢂ 10 ml) and dried in
vacuo. Yield: 65 mg (84%). Crystals suitable for X-ray diffraction
were obtained by diffusion of n-hexane into a dichloromethane
161.98 MHz
( a Bruker AV-500 NMR spectrometer
31P), and
solution. m.p. 270–273 °C (dec.). IR (KBr, cmꢀ1): 2141
m(CN).
equipped with a 5 mm TBO probe head, operating at 500.13 MHz
(1H), 125.76 MHz (13C), 202.46 MHz (31P). The chemical shifts are
reported in d values in ppm relative to external SiMe4 (1H, 13C),
31P{1H} NMR (CD2Cl2), d: ꢀ0.4 (s). 1H NMR (CD2Cl2), d: 4.08 (s,
4H, CH2P), 6.63 (d, 3JHH = 8.1 Hz, 2H, o-CH, NPh), 7.03 (t, 3JHH = 7.3 -
Hz, 1H, p-CH, NPh), 7.20 (m, 2H, m-CH, NPh), 7.49 (m, 8H, PPh),
7.58 (m, 4H, p-CH, PPh), 7.74 (m, 8H, PPh). 13C{1H} NMR (CD2Cl2),
d: 55.4 (m, N = |1JCP + 3JCP| = 44.3 Hz, CH2P), 120.5 (s, o-C, NPh),
85% aq H3PO4
onance frequency and
(
31P) using the chemical shift of the solvent 2H res-
N
= 40.480742% for 31P. All assignments are
supported by 2D NMR experiments (1H1H COSY, 13C1H HSQC, 31P1H
HSQC). Melting temperatures were measured on a BÜCHI Melting
Point B-540 device. Infrared spectra were obtained as KBr discs
on a Bruker Vertex 70 FT-IR-spectrometer with a resolution of
4 cmꢀ1 and 16 scans from 400 to 4000 cmꢀ1 versus pure KBr as
blank. ESI mass spectra were recorded on a Bruker Esquire 3000+
mass analyzer. Fast atom bombardment (FAB) mass spectra were
measured on a Finnigan MAT, TSQ 70 mass analyzer using 3-nitro-
benzylalcohol as matrix. Elemental analyses were performed using
3
124.4 (s, p-C, NPh), 130.2 (s, m-C, NPh), 152.4 (t, JCP = 7.4 Hz,
ipso-C, NPh), 126.5 (m, N = |1JCP + 3JCP| = 114.8 Hz, ipso-C, PPh),
129.5 (m, PPh), 132.5 (m, PPh), 134.2 (m, PPh), 128.5 (m, N =
|2JCPcis + 2JCPtrans| = 51.6 Hz, CNꢀ). ESI–MS (m/z): 621.1 [MꢀCN]+.
Anal. Calc. for C34H29N3P2Pd: C, 63.02, H, 4.51, N, 6.48. Found C,
63.12, H, 4.28, N, 6.59%.
2.4. General procedure for the preparation of [PtX2{PhN(CH2PPh2)2}]
(X = Cl, Br)
a
Vario EL analyzer from Elemental Company. Bis(bromo-
methyl)sulfide [26], [Ir(CO)2(p-toluidine)Cl] [27], IrCl(CO)(PPh3)2
[28], RhCl(CO)(PPh3)2 [29,30], [PdCl2{PhN(CH2PPh2)2}] (1c) [17]
and the ligands 1–4 [17,23–25] were prepared according to litera-
ture procedures.
A solution of CODPtX2 (1 equiv.) in 5 ml of DCM was added to a
solution of 1 (1 equiv.) in 2 ml of DCM. The resulting yellow solu-
tion was stirred at rt for 30 min. Then two thirds of the solvent
were removed under reduced pressure. An excess of diethylether
was added to precipitate the product as a colorless solid which
was washed successively with diethylether (2 ꢂ 5 ml) and metha-
nol (1 ꢂ 5 ml) and dried in vacuo.
2.1. Synthesis of [RhCl(CO){PhN(CH2PPh2)2}2] (1a)
About 47 mg (0.07 mmol) of RhCl(CO)(PPh3)2 were dissolved in
10 ml of toluene. The yellow solution was added to 66 mg
(0.14 mmol) of 1. The resulting yellow suspension was heated to
80 °C for 1 h and then cooled to rt. Two thirds of the solvent were re-
moved under reduced pressure. Diethyl ether was added until com-
plete precipitation occurred. The solid was filtered, washed with n-
hexane and dried in vacuo. Yield: 79 mg (99%). m.p. 176–178 °C
2.4.1. Synthesis of [PtCl2{PhN(CH2PPh2)2}] (1d)
CODPtCl2 (11 mg, 0.03 mmol) and 1 (14 mg, 0.03 mmol) gave
1d (18 mg, 85%). Crystals suitable for X-ray diffraction were
obtained by diffusion of n-hexane into
a
chloroform
solution. m.p. 293–295 °C (dec.). 31P{1H} NMR (CDCl3), d: ꢀ5.5
1
2
(s; d, JPPt = 3418.6 Hz). 1H NMR (CDCl3), d: 4.05 (d, JHP = 2.6 Hz;
(dec.). IR (KBr, cmꢀ1): 1965
m
(CO). 31P{1H} NMR (CDCl3), d: 10.0 (d,
3
3
dd, JHPt = 41.6 Hz, 4H, CH2P), 6.67 (d, JHH = 8.7 Hz, 2 H, o-CH,
3-
1JPRh = 130.0 Hz). 1H NMR (CDCl3), d: 3.94 (s, 8H, CH2P), 6.23 (d,
3
NPh), 7.00 (t, JHH = 7.4 Hz, 1H, p-CH, NPh), 7.21 (m, 2H, m-CH,
3
JHH = 8.7 Hz, 4H, o-CH, NPh), 6.77 (t, JHH = 7.3 Hz, 2H, p-CH, NPh),
NPh), 7.42 (m, 8H, PPh), 7.50 (m, 4H, p-CH, PPh), 7.83 (m, 8H,
PPh). 13C{1H} NMR (CDCl3), d: 52.9 (m, N = |1JCP + 3JCP| = 53.3 Hz,
CH2P), 118.5 (s, o-C, NPh), 122.9 (s, p-C, NPh), 129.6 (s, m-C,
7.01 (m, 4H, m-CH, NPh), 7.14 (m, 16H, PPh), 7.23 (m, 16H, p-CH,
PPh), 7.37 (m, 16 H, PPh). 13C{1H} NMR (CDCl3), d: 60.0 (m, CH2P),
121.8 (s, o-C, NPh), 128.5 (s, m-C, NPh), 130.1 (s, p-C, NPh), 151.0
(m, ipso-C, NPh), 128.1–133.8 (m, PPh). FAB-MS (m/z): 1081.2
[M–Cl–CO]+. Anal. Calc. for C65H58ClN2OP4Rhꢁ0.5C6H14: C, 68.72, H,
5.51, N, 2.36. Found C, 69.12, H, 5.30, N, 2.47%.
3
3-
NPh), 152.1 (t, JCP = 7.3 Hz, ipso-C, NPh), 127.5 (m, N = |1JCP
+
JCP| = 64.4 Hz, ipso-C, PPh), 128.6 (m, PPh), 131.7 (m, PPh),
133.7 (m, PPh). FAB-MS (m/z): 719.2 [MꢀCl]+. Anal. Calc. for C32-
H29Cl2NP2PtꢁCH3OH: C, 50.33, H, 4.22, N, 1.78. Found: C, 50.27,
H, 3.98, N, 1.76%.
2.2. Synthesis of [IrCl(CO){PhN(CH2PPh2)2}2] (1b)
2.4.2. Synthesis of [PtBr2{PhN(CH2PPh2)2}] (1d0)
A mixture of 85 mg (0.18 mmol) of 1 and 54 mg (0.07 mmol) of
IrCl(CO)(PPh3)2 was dissolved in 5 ml of toluene and heated to
CODPtBr2 (13 mg, 0.03 mmol) and 1 (14 mg, 0.03 mmol) gave
1d0 (19 mg, 85%). Crystals suitable for X-ray diffraction were

M. Stickel et al. / Polyhedron 46 (2012) 95–104
97
obtained by diffusion of n-hexane into a dichloromethane solution.
m.p. 305–307 °C (dec.). 31P{1H} NMR (CDCl3), d: ꢀ6.5
2.6.1. Synthesis of [RhCl(CO){PhN(CH2PtBu2)2}] (2a)
Compound 2 (35 mg, 0.09 mmol) and RhCl(CO)(PPh3)2 (50 mg,
0.07 mmol) gave 2a (35 mg, 84%). m.p. 230–234 °C (dec.). IR (KBr,
1
2
(s; d, JPPt = 3362.6). 1H NMR (CDCl3), d: 4.05 (d, JHP = 2.4 Hz; dd,
3JHPt = 41.8 Hz, 4H, CH2P), 6.61 (m, 2H, o-CH, NPh), 6.97 (m, 1H,
p-CH, NPh), 7.18 (m, 2H, m-CH, NPh), 7.42 (m, 8H, PPh), 7.49 (m,
4H, p-CH, PPh), 7.84 (m, 8H, PPh). 13C{1H} NMR (CDCl3), d: 52.6
(m, N = |1JCP + 3JCP| = 52.7 Hz, CH2P), 118.3 (s, o-C, NPh), 122.9 (s,
cmꢀ1): 1994 (CO). 31P{1H} NMR (C6D6), d: 20.8 (dd, 1JP1Rh = 121.9 -
m
Hz, 2JP1P2 = 38.2 Hz, P1), 61.0 (dd, 1JP2Rh = 162.1 Hz, 2JP2P1 = 38.2 Hz,
3
P2). 1H NMR (C6D6), d: 1.11 (d, JH4P2 = 12.9 Hz, 18H, H4), 1.43
3
2
(d, JH2P1 = 12.7 Hz, 18H, H2), 3.07 (d, JH1P1 = 2.6 Hz, 2H, H1), 3.13
3
2
3
p-C, NPh), 129.8 (s, m-C, NPh), 152.1 (t, JCP = 7.3 Hz, ipso-C, NPh),
(d, JH3P2 = 3.2 Hz, 2H, H3), 6.93 (t, JHH = 7.3 Hz, 1H, p-CH), 7.02
(m, 2H, o-CH), 7.16 (m, 2H, m-CH). 13C{1H} NMR (C6D6), d: 30.2
(d, 2JC4P2 = 3.8 Hz, C4), 31.1 (d, 2JC2P1 = 4.2 Hz, C2), 36.9
127.9 (m, N = |1JCP + 3JCP| = 64.3 Hz, ipso-C, PPh), 128.8 (m, PPh),
131.9 (m, PPh), 133.9 (m, PPh). FAB-MS (m/z): 764.1 [MꢀBr]+. Anal.
Calc. for C32H29Br2NP2Pt: C, 45.52, H, 3.46, N, 1.66. Found: C, 45.50,
H, 3.11, N, 1.51%.
1
1
(d, JCP = 12.9 Hz, C(CH3)3), 37.5 (d, JCP = 20.8 Hz, C(CH3)3), 51.7
1
1
(d, JC3P2 = 28.1 Hz, C3), 52.6 (d, JC1P1 = 24.5 Hz, C1), 121.7 (s, o-C,
NPh), 124.1 (s, p-C, NPh), 130.1 (s, m-C, NPh), 156.3 (t, 3JCP = 8.2 Hz,
ipso-C, NPh). FAB-MS (m/z): 540.2 [MꢀCl]+, 512.2 [MꢀClꢀCO]+.
Anal. Calc. for C25H45ClNOP2Rh: C, 52.14, H, 7.88, N, 2.43. Found
C, 52.39, H, 8.13, N, 2.45%.
2.5. Synthesis of [Pt(CN)2{PhN(CH2PPh2)2}] (1d00)
To a solution of 22 mg (0.03 mmol) of 1d0 in 5 ml of DCM was
added a solution of 3 mg (0.06 mmol) of NaCN dissolved in 5 ml
of MeOH. The colorless suspension was stirred at rt for 24 h until
a clear solution had formed. Removal of the solvent gave a white
powder which was washed with diethylether (1 ꢂ 10 ml) and
methanol (1 ꢂ 5 ml) and dried in vacuo. Yield: 15 mg (68%). Crys-
tals suitable for X-ray diffraction were obtained by diffusion of
n-hexane into a chloroform solution. m.p. 288–290 °C (dec.).
2.6.2. Synthesis of [IrCl(CO){PhN(CH2PtBu2)2}] (2b)
Compound 2 (59 mg, 0.14 mmol) and IrCl(CO)(PPh3)2 (84 mg,
0.11 mmol) gave 2b (60 mg, 60%). m.p. 207–209 °C (dec.). IR (KBr,
cmꢀ1): 1983
m
(CO). 31P{1H} NMR (C6D6), d: 14.5 (d, 2JP1P2 = 25.2 Hz,
2
P1), 30.3 (d, JP2P1 = 25.2 Hz, P2). 1H NMR (C6D6), d: 1.13 (d,
3JH4P2 = 12.9 Hz, 18H, H4), 1.43 (d, JH2P1 = 12.8 Hz, 18H, H2), 3.16
3
2
2
(d, JH1P1 = 3.0 Hz, 2H, H1), 3.25 (d, JH3P2 = 3.5 Hz, 2H, H3), 6.93 (t,
3JHH = 7.3 Hz, 1H, p-CH, NPh), 7.03 (m, 2H, o-CH, NPh), 7.16 (m,
IR (KBr, cmꢀ1): 2145
m
(CN). 31P{1H} NMR (CDCl3), d: ꢀ11.9
2H, m-CH, NPh). 13C{1H} NMR (C6D6), d: 30.0 (d, JC4P2 = 2.5 Hz,
2
1
2
(s; d, JPPt = 2362.9 Hz). 1H NMR (CD2Cl2), d: 4.09 (d, JHP = 1.8 Hz;
2
1
3
3
C4), 31.2 (d, JC2P1 = 2.9 Hz, C2), 37.8 (d, JCP = 19.6 Hz, C(CH3)3),
dd, JHPt = 25.1 Hz, 4H, CH2P), 6.63 (d, JHH = 7.5 Hz, 2H, o-CH,
NPh), 7.04 (t, JHH = 6.8 Hz, 1H, p-CH, NPh), 7.20 (m, 2H, m-CH,
1
1
3
38.1 (d, JCP = 11.4, C(CH3)3), 51.2 (d, JC3P2 = 35.0 Hz, C3), 52.3 (d,
1JC1P1 = 30.9 Hz, C1), 121.6 (s, o-C), 124.1 (s, p-C), 130.1 (s, m-C),
NPh), 7.44 (m, 8H, PPh), 7.51 (m, 4H, p-CH, PPh), 7.71 (m, 8H,
3
156.2 (t, JCP = 8.3 Hz, ipso-C). FAB-MS (m/z): 637.2 [M-CO]+. Anal.
PPh). 13C{1H} NMR (CD2Cl2), d: 54.2 (m, N = |1JCP
+
3JCP|=49.4 Hz,
Calc. for C25H45ClIrNOP2ꢁEtOH: C, 45.59, H, 7.23, N, 1.97. Found C,
CH2P), 120.1 (s, o-C, NPh), 124.2 (s, p-C, NPh), 130.0 (s, m-C,
3
NPh), 152.4 (t, JCP = 7.7 Hz, ipso-C, NPh), 122.5 (m, N = |1JCP
+
45.72, H, 7.17, N, 1.66%.
3JCP|=107.5 Hz, ipso-C, PPh), 129.3 (m, PPh), 132.3 (m, PPh),
133.8 (m, PPh), 127.7 (m, N = |2JCPcis + 2JCPtrans| = 59.8 Hz, CN).
ESI–MS (m/z): 737.2 [M+H+]. Anal. Calc. for C34H29N3P2-
Ptꢁ0.5CHCl3: C, 52.03, H, 3.73, N, 5.28. Found C, 52.36, H, 3.74,
N, 5.20%.
2.6.3. Synthesis of [RhCl(CO){PhN(CH2PCy2)2}] (3a)
Compound 3 (64 mg, 0.13 mmol) and RhCl(CO)(PPh3)2 (72 mg,
0.11 mmol) gave 3a (42 mg, 59%). m.p. 182–184 °C (dec.). IR (KBr,
cmꢀ1): 1987 (CO). 31P{1H} NMR (C6D6), d: 11.2 (dd, 1JP1Rh = 119.1 -
m
Hz, 1JP1P2 = 43.1 Hz, P1), 39.2 (dd, 1JP2Rh = 153.5 Hz, 1JP1P2 = 43.1 Hz,
P2). 1H NMR (C6D6), d: 0.8–2.6 (m, Cy, 44H), 3.05 (d, 2JH1P1 = 3.1 Hz,
2H, H1), 3.12 (br. s, 2H, H3), 6.8–7.4 (m, 5H, NPh). 13C{1H} NMR
2.6. General procedure for the preparation of [MCl(CO)(L)] (2a, 2b, 3a,
3b)
1
(C6D6), d: 25.8–39.1 (Cy), 49.7 (d, JCP = 30.7 Hz, C1), 50.6
1
(d, JCP = 36.0 Hz, C3), 118.6 (s, NPh), 122.1 (s, NPh), 129.9 (s,
NPh), 153.8 (t, 3JCP = 6.6 Hz, ipso-C). FAB-MS (m/z): 651.2 [MꢀCO]+.
Anal. Calc. for C33H53ClNOP2Rh: C, 58.28, H, 7.86, N, 2.06. Found C,
58.29, H, 7.64, N, 2.07%.
A mixture of ligand (1.2 equiv.) and MCl(CO)(PPh3)2 in 5 ml of
toluene was heated to 80 °C for 20 h. Removal of the solvent gave
yellow to orange solids which were dissolved in 10 ml of diethyl-
ether and filtered over silica to remove unreacted MCl(CO)(PPh3)2.
All the solvent except for 1 ml was removed under reduced pres-
sure. Then 20 ml of n-hexane were added and the solution was
cooled to ꢀ30 °C for 16 h. Yellow to orange crystals formed which
were washed with n-hexane (3 ꢂ 5 ml) and ethanol (1 ꢂ 2 ml) and
dried in vacuo (Fig. 1).
2.6.4. Synthesis of [IrCl(CO){PhN(CH2PCy2)2}] (3b)
Compound 3 (71 mg, 0.14 mmol) and IrCl(CO)(PPh3)2 (90 mg,
0.12 mmol) gave 3b (63 mg, 71%). m.p. 204–206 °C (dec.). IR (KBr,
cmꢀ1): 1973
m
(CO). 31P{1H} NMR (C6D6), d: 5.0 (d, JP1P2 = 29.6 Hz,
1
1
P1), 8.4 (d, JP2P1 = 29.6 Hz, P2). 1H NMR (C6D6), d: 0.8–2.7 (m, 44H,
2
2
Cy), 3.16 (d, JH1P1 = 3.4 Hz, 1H, H1), 3.28 (d, JH2P2 = 3.1 Hz, 1H,
3
3
H2), 7.07 (d, JHH = 7.9 Hz, 2H, o-CH, NPh), 7.12 (t, JHH = 7.4 Hz,
1H, p-CH, NPh), 7.40 (m, 2H, m-CH, NPh). 13C{1H} NMR (C6D6), d:
26.4–38.9 (Cy), 49.5 (d, 1JC1P1 = 16.9 Hz, C1), 49.9 (d, 1JC2P2 = 21.7 Hz,
C2), 118.4 (s, NPh), 122.0 (s, NPh), 130.0 (s, NPh), 153.8 (t, 3JCP = 6.7
Hz, ipso-C). FAB (m/z): 732.3 [MꢀCl]+. Anal. Calc. for C33H53ClIr-
NOP2ꢁEt2O: C, 52.68, H, 7.53, N, 1.66. Found C, 52.27, H, 7.55, N,
1.62%.
2.7. Synthesis of [PdCl2{PhN(CH2PtBu2)2}] (2c)
A THF solution of 71 mg (0.17 mmol) of 2 and 55 mg (0.14 mmol)
of Pd(PhCN)2Cl2 was heated to 65 °C for 18 h. The precipitate was fil-
tered off and washed successively with 5 ml n-hexane and twice
with 5 ml ether each. The resulting colorless solid was dried under
Fig. 1. Numbering for NMR assignments.

98
M. Stickel et al. / Polyhedron 46 (2012) 95–104
reduced pressure for 20 h. Yield: 70 mg (85%). m.p. 310–312 °C
(dec.). 31P{1H} NMR (CDCl3) d: 38.9 (s). 1H NMR (CDCl3), d: 1.57 (d,
50 °C. After 10 min the salt started to precipitate as a colorless so-
lid. After 12 h at 50 °C the solid was collected by filtration, washed
twice with ether (2 ꢂ 10 ml) and dried under reduced pressure.
Yield: 580 mg (42%). m.p. 288 °C. 31P{1H} NMR (D2O), d: 44.1
2
3JHP = 14.1 Hz, 36H, CH3), 3.43 (d, JHP = 2.23 Hz, 4H, CH2P), 7.21
(m, 3H, o-CH, p-CH, NPh), 7.41 (m, 2H, m-CH, NPh). 13C{1H} NMR
(CDCl3), d: 31.4 (s, CH3), 39.5 (m, N = |1JCP + 3JCP| = 17.4 Hz,
C(CH3)3), 52.3 (m, N = |1JCP + 3JCP| = 32.1 Hz, CH2P), 122.8 (s, o-C),
3
(s). 1H NMR (D2O), d: 1.62 (d, JHP = 17.5 Hz, 36H, CH3), 3.98
(d, 2JHP = 9.8 Hz, 4H, CH2P), (phosphonium-protons not detectable).
3
125.7 (s, p-C), 130.3 (s, m-C), 155.0 (t, JCP = 8.7, ipso-C). FAB-MS
13C{1H} NMR (D2O), d: 17.9 (m, N = |1JCP + 3JCP| = 46.5 Hz, CH2P),
(m/z): 654.6 [MꢀCl]+. Anal. Calc. for C24H45Cl2NP2Pd: C, 49.12, H,
26.6 (s, CH3), 33.3 (d, JCP = 31.8 Hz, C(CH3)3). FAB-MS (m/z):
1
7.73, N, 2.39, N, 1.97. Found C, 49.00, H, 8.05, N, 2.40%.
351.2 [MꢀHꢀBr2]+. Anal. Calc. for C18H42Br2P2S: C, 42.20, H, 8.26,
S, 6.26. Found C, 42.28, H, 7.89, S, 6.07%.
2.8. Synthesis of [PtBr2{PhN(CH2PtBu2)2}] (2d0)
2.12. Synthesis of [PtCl2{S(CH2PPh2)2}] (4d)
A solution of 88 mg (0.19 mmol) of CODPtBr2 in 5 ml of toluene
was added to a toluene solution of 89 mg (0.22 mmol) of 2. The
pale yellow suspension was heated to 80 °C for 24 h. The resulting
yellow solution was cooled to rt and mixed with 10 ml of n-hexane.
The precipitated yellow solid was filtered off, washed with n-hex-
ane and dried in vacuo. Yield: 75 mg (58%). m.p. 319–321 °C (dec.).
A solution of 20 mg (0.05 mmol) of CODPtCl2 in 2 ml of DCM
was added to 28 mg (0.07 mmol) of 4 in 5 ml of DCM. The resulting
colorless solution was stirred for 16 h at rt. The solvent was re-
moved by two thirds and diethyl ether was added until complete
precipitation occurred. The colorless solid was filtered, washed
once with 10 ml diethyl ether and twice with 10 ml n-pentane
each und dried under reduced pressure. Crystals suitable for
X-ray diffraction were obtained by diffusion of n-hexane into a
dichloromethane solution. Yield: 38 mg (>99%). m.p. 373 °C
1
31P{1H} NMR (CD2Cl2) d: 15.8 (s; d, JPPt = 3521.2 Hz). 1H NMR
2
(CD2Cl2) d: 1.56 (d, 3JHP = 13.8 Hz, 36H, CH3), 3.56 (d, JHP = 3.0 Hz;
3
dd, JHPt = 13.2 Hz, 4H, CH2P), 7.19 (m, 3H, o-CH, p-CH, NPh), 7.41
(m, 2H, m-CH, NPh). 13C{1H} NMR (CD2Cl2), d: 31.8 (s, CH3), 39.6
(m, N = |1JCP + 3JCP| = 25.1 Hz, C(CH3)3), 52.0 (m, N = |1JCP
+
(dec.). 31P{1H} NMR (CD2Cl2), d: ꢀ7.3 (s; d, JPPt = 3570.0 Hz). 1H
1
3JCP| = 38.8 Hz, CH2P), 122.7 (s, o-C), 125.4 (s, p-C), 130.4 (s, m-C),
2
3
NMR (CD2Cl2), d: 3.42 (d, JHP = 5.0 Hz; dd, JHPt = 39.2 Hz, 4H,
CH2P), 7.52, 7.87 (m, 20 H, Ph). 13C{1H} NMR (CD2Cl2), d: 28.8 (m,
CH2P), 129.0 (m, Ph), 132.1 (s, Ph), 134.3 (m, Ph). FAB-MS (m/z):
661.1 [MꢀCl]+. Anal. Calc. for C26H24Cl2P2PtS: C, 44.84, H, 3.47, S,
4.60. Found C, 45.08, H, 3.40, S, 4.52%.
3
155.3 (t, JCP = 8.7, ipso-C Hz). FAB-MS (m/z): 684.2 [MꢀBr]+. Anal.
Calc. for C24H45Br2NP2Pt: C, 37.71, H, 5.93, N, 1.83, N, 1.97. Found
C, 38.11, H, 5.57, N, 1.93%.
2.9. Synthesis of [PdCl2{PhN(CH2PCy2)2}] (3c)
2.13. Synthesis of [Ir2Cl2(l
-{S(CH2PtBu2)2}2(CO)2] (5b)
A suspension of 62 mg (0.12 mmol) of 3 and 41 mg (0.11 mmol)
of Pd(PhCN)2Cl2 in 5 ml of toluene was heated to 80 °C for 20 h. The
resulting yellow suspension was filtered. The yellow solid was suc-
cessively washed with diethylether (1 ꢂ 5 ml) and n-hexane
(2 ꢂ 5 ml) and dried under reduced pressure. Yield: 75 mg (99%).
m.p. 318–322 °C (dec.). 31P{1H} NMR (CD2Cl2), d: 28.9 (s). 1H NMR
About 19 mg (0.04 mmol) of 50 were suspended in 4 ml of tolu-
ene. Then a solution of 15 mg (0.04 mmol) of Ir(CO)2Cl(p-TolNH2)
in 4 ml of toluene was slowly added (1 h). The resulting bright yel-
low suspension was stirred for 16 h at rt. The reaction mixture was
hydrolyzed and extracted three times with 5 ml of toluene each.
The combined organic extracts were dried over Na2SO4 and the sol-
vent was removed under reduced pressure. Recrystallization from
toluene/n-hexane afforded a yellow solid. Crystals suitable for
X-ray diffraction were obtained by diffusion of n-hexane into a
dichloromethane solution. Yield: 12 mg (54%). m.p. 232–236 °C
3-
(CD2Cl2), d: 1.1–2.6 (m, 44H, Cy), 3.36 (s, 4H. CH2P), 7.07 (d,
3
JHH = 7.9 Hz, 2H, o-CH, NPh), 7.12 (t, JHH = 7.4 Hz, 1H, p-CH NPh),
7.40 (m, 2H, m-CH, NPh). 13C{1H} NMR (CD2Cl2), d: 26.7–37.7 (Cy),
49.6 (m, N = |1JCP + 3JCP| = 40.6 Hz, CH2P), 120.9 (s, o-C, NPh), 124.5
3
(s, p-C, NPh), 130.8 (s, m-C, NPh), 151.7 (t, JCP = 7.8 Hz, ipso-C).
FAB-MS (m/z): 654.3 [MꢀCl]+. Anal. Calc. for C32H29Cl2NP2Pd: C,
(dec.). IR (KBr, cmꢀ1): 1960 (CO). 31P{1H} NMR (C6D6), d: 36.1
m
55.62, H, 7.73, N, 2.03. Found C, 55.75, H, 7.45, N, 2.09%.
(s). 1H NMR (C6D6), d: 1.40 (m, N = |3JCP + 5JCP| = 12.5 Hz, 36H,
CH3), 1.72 (m, N = |3JCP + 5JCP| = 12.7 Hz, 36H, CH3). ESI–MS (m/z):
1175.4 [MꢀCl]+. Anal. Calc. for C38H80Cl2Ir2O2P4S2ꢁC7H8: C, 41.43,
H, 6.80, S, 4.92. Found C, 41.29, H, 7.10, S, 3.68%.
2.10. Synthesis of [PtCl2{PhN(CH2PCy2)2}] (3d)
About 72 mg (0.15 mmol) of CODPtCl2 in 10 ml of THF were
added to a THF solution of 93 mg (0.18 mmol) of 3. After 10 min
a colorless solid started to precipitate. The reaction mixture was
stirred for 24 h at rt. The solid was filtered, washed with diethyl-
ether and dried in vacuo. Yield: 83 mg (70%). m.p. 315–318 °C
3. Single crystal X-ray diffraction studies
Crystal data and details of the structure determination are pre-
sented in Table 2 (also see Table S1 in the supporting information).
X-ray data for compounds 1b0 and 1c00 were collected on a Stoe
IPDS 2T diffractometer; X-ray data for compounds 2b, 4d and 5b
were collected on a Bruker 3 circuit APEX II diffractometer. A mul-
1
(dec.). 31P{1H} NMR (CD2Cl2), d: 4.9 (s; d, JPPt = 3454.6 Hz), 1H
2
NMR (CD2Cl2), d: 1.2–2.6 (m, 44H, Cy), 3.43 (d, JHP = 2.1 Hz; dd,
3
3JHPt = 30.6 Hz, 4H, CH2P), 7.04 (d, JHH = 8.8 Hz, 2H, o-CH, NPh),
3
7.09 (t, JHH = 7.4 Hz, 1H, p-CH, NPh), 7.38 (m, 2H, m-CH, NPh).
13C{1H} NMR (CD2Cl2), d: 26.4–36.1 (Cy), 48.6 (m, N = |1JCP
+
tilayer monochromated Mo Ka radiation (k = 0.71073 Å) was used.
3JCP| = 46.9 Hz, CH2P), 119.7 (s, o-C), 123.5 (s, p-C), 130.2 (s, m-C),
The data were corrected for Lorentz and polarization effects and
absorption by air. The programs used in this work are the WinGX
suite of programs [31] including SHELXS and SHELXL [32] for structure
solution and refinement. Numerical absorption correction based on
crystal-shape optimization was applied for compounds 1b0 and 1c00
with Stoe’s X-RED and X-SHAPE [33,34] out of Stoe’s X-AREA suite of pro-
grams [35] and for compounds 2b, 4d and 5b using Bruker’s SADABS
software package [36]. The hydrogen atoms were placed in calcu-
lated positions and refined as riding on their respective C-atom,
with Uiso(H) set at 1.2 Ueq(Csp2) and 1.5 Ueq(Csp3).
3
153.5 (t, JCP = 7.8 Hz, ipso-C). ESI–MS (m/z): 743.4[MꢀCl]+, 802.2.
Anal. Calc. for C32H53Cl2NP2PtꢁCH2Cl2: C, 45.84, H, 6.41, N, 1.62.
Found C, 46.21, H, 6.57, N, 1.54%.
2.11. Synthesis of [S(CH2PHtBu2)2]Br2 (50)
About 1 ml (5.40 mmol) of di-tert-butylphosphine was added
dropwise to a stirred mixture of 270
ll (3.35 mmol) of bis(bromo-
methyl)sulfide and 10 ml of acetone. The solution was heated to

M. Stickel et al. / Polyhedron 46 (2012) 95–104
99
4.2. Pd(II) and Pt(II) complexes
4. Results and discussion
Symmetric mononuclear Pd(II) and Pt(II) complexes 1d, 1d0, 2c,
2d0, 3c, 3d and 4d were obtained by the reaction of the ligands 1–4
with equimolar amounts of dichlorobis(benzonitrile)- and
dihalogenocyclooctadiene palladium(II) or platinum(II) precursors
according to Scheme 2. All complexes were obtained as colorless
to yellow powdery solids soluble in halogenated solvents and
THF, insoluble in diethyl ether and hydrocarbons. They are insensi-
tive to air and can be kept at room temperature without decom-
posing. In each case the cis square planar Pd(II) and Pt(II)
complexes were generated independent of the heteroatom in the
ligand backbone and the steric requirements of the functional
group at the phosphorus atom. This is in contrast to the bisphos-
phine Ph2P(CH2)3PPh2 which was reported to form a dinuclear cis
complex with the PtCl2 fragment [37]. Interestingly, the treatment
of 5 with MCl2(PhCN)2 (M = Pd, Pt) always resulted in insoluble
compounds.
There are well known examples in which the trans directing
cyanide ion allows the formation of trans bisphosphine complexes
from formerly cisoide mononuclear halogeno compounds [14]. In
spite of that, the treatment of [PdCl2{PhN(CH2PPh2)2}] with an ex-
cess of sodium cyanide in a methanol/DCM mixture gave the
monometallic cis dicyano complex 1c00. Similarly, 1d was reacted
with NaCN to give the analogous cis platinum complex 1d00
(Scheme 3). Both 1c00 and 1d00 were obtained in good yields as air
stable colorless solids which are soluble in halogenated solvents.
X-ray structures of symmetric Pd(II) and Pt(II) complexes are
shown with labeled atoms in Figs. 2 and 4 with selected molecular
dimensions as well as in the Figs. S1–S4 and Table S1 (supporting
information, Table 1). The cis dicyano and dihalogeno complexes
1c00 and 4d consist of square planar MP2X2 cores with a flattened
boat conformation which is comparable to those observed in re-
lated compounds like [PdCl2{PhP(CH2PPh2)2}] [20] and [PdCl2
{PhN(CH2PPh2)2}] [17]. Interatomic distances and angles are in a
normal range [17,20]. The large Pd1ꢁ ꢁ ꢁN14 [3.697(3) Å] and
Pt1ꢁ ꢁ ꢁS1 [3.904(9) Å] distances exclude a direct bonding between
the donor atoms nitrogen and the metal centers Pd(II), respec-
tively, as well as sulfur and Pt(II).
4.1. Synthesis of the ligands
The symmetric bis(phosphinomethyl)phenylamine ligands 1–3
(Chart 1) were accessible by the treatment of two equivalents of
the
corresponding
hydroxymethylphosphine
R2PCH2OH
t
[R = Ph(1), Bu(2), Cy(3)] with one equivalent of aniline [17,24,25].
The tert-butyl- and cyclohexyl-phosphines 2 and 3 decompose in
halogenated solvents so that reactions were carried out in THF.
The reaction of bis(chloromethyl)sulfide with LiPPh2 in THF affords
colorless bis(diphenylphosphinomethyl)sulfide (4, Chart 1) [23].
The bisphosphines 1–4 were characterized by their 1H, 13C and
31P NMR spectra. All spectra were compatible with those reported
earlier [17,23–25].
Treatment of bis(bromomethyl)sulfide with two equiv of
di-tert-butylphosphine in acetone leads to the formation of the
ionic bis(di-tert-butylphosphoniummethyl)sulfide dibromide (50)
in moderate yields (Scheme 1). The singlet in the 31P{1H} NMR
spectrum as well as the number of resonances in the 1H and
13C{1H} NMR spectra agree with the structure of the molecule as
shown in Scheme 1. The composition of 50 has been confirmed by
elemental analysis and mass spectrometry. Deprotonating 50 by
stoichiometric reaction with n-butyllithium in diethylether affords
bis(di-tert-butylphosphinomethyl)sulfide (5, Chart 1) in quantita-
tive yield according to 1H NMR spectroscopy.
The five ligand systems (1–5) are equipped with potentially
three coordination centers, two at the phosphorus atoms and one
at the nitrogen and sulfur, respectively. Following the concept of
hard acids and soft bases (HSAB) it is expected that soft late tran-
sition metal ions (d8) prefer coordination to the phosphines while
the nitrogen and sulfur, respectively, show no or very weak inter-
action with these metals [17].
All NMR data of the palladium and platinum complexes are
compatible with a C2v symmetry of the compounds. Thus the
31P{1H} NMR spectra display singlets for the complexes 1c00, 1d,
1d0, 1d00, 2c, 2d0, 3c, 3d and 4d which differ from the chemical shifts
of the free ligands 1–4 and support their coordination to the metal
centers (Table 2) [38]. In the case of dihalogeno Pt(II) complexes
1d, 1d0, 2d0, 3d, and 4d platinum satellites are obtained with phos-
phorus–platinum coupling constants between 3300 and 3500 Hz.
The size of the coupling constants is characteristic for platinum(II)
coordinated by two mutually cis positioned phosphorus atoms and
phosphorus trans to ligands with a weak trans influence (Table 2)
[39–42]. In 1d00 the strong trans influence ligand causes a reduced
1JPtP coupling of 2362.9 Hz [12,14]. One set of signals in the 1H
NMR spectra for all four substituents at the phosphorus atoms as
Chart 1. Substituents in 1–5.
Scheme 1. Synthesis of 50.
Scheme 2. General synthetic route to symmetric complexes.
Scheme 3. Synthesis of symmetric dicyano complexes.

100
M. Stickel et al. / Polyhedron 46 (2012) 95–104
Fig. 4. Molecular structure of 1c00. Thermal ellipsoids are drawn at 50% probability
level (hydrogen atoms are omitted for clarity). Selected bond lengths (Å) and angles
(°): P1–Pd1 2.292(1), Pd1–P2 2.308(1), P2–C15 1.848(4), C15–N14 1.460(4), N14–
C13 1.463(4), C13–P1 1.844(4), Pd1–C01 2.006(4), C01–N01 1.144(5), Pd1–C02
2.006(4), C02–N02 1.147(5), Pd1ꢁ ꢁ ꢁN14 3.697(3); Pd1–P1–C13 117.4(1), P1–C13–
N14 112.5(2), C13–N14–C15 113.9(3), N14–C15–P2 112.4(2), C15–P2–Pd1
114.2(1), P2–Pd1–P1 95.91(4), P2–Pd1–C01 88.7(1), P2–Pd1–C02 175.6(1), P1–
Pd1–C02 88.4(1), P1–Pd1–C01 169.4(1), C02–Pd1–C01 87.1(1).
Fig. 2. Molecular structure of 4d. Thermal ellipsoids are drawn at 50% probability
level (hydrogen atoms are omitted for clarity). Selected bond lengths (Å) and angles
(°): P1–Pt1 2.230(5), Pt1–P2 2.229(9), P2–C1 1.833(1), C1–S1 1.808(1), S1–C2
1.809(1), C2–P1 1.827(2), Pt1–Cl1 2.360(8), Pt1–CL2 2.349(0), Pt1ꢁ ꢁ ꢁS1 3.904(9);
Pt1–PP1–C2 119.01(5), P1–C2–S1 112.82(8), C2–S1–C1 97.13(7), S1–C1–P2
113.13(8), C1–P2–Pt1 119.03(5), P2–Pt1–P1 99.45(1), P1–Pt1–Cl2 172.73(1), P1–
Pt1–Cl1 85.28(1), P2–Pt1–Cl1 175.06(1), P2–Pt1–Cl2 85.96(1), Cl1–Pt1–Cl2
89.45(1).
gave the trigonal bipyramidal complex 1a as an intense yellow
solid in poor yield (Scheme 4). Changing the ligand to rhodium pre-
cursor ratio to 4:1 increased the yield to up to 60%. When
RhCl(CO)(PPh3)2 is applied as metal precursor a quantitative con-
version to 1a is obtained (Scheme 4). The trigonal bipyramidal
complex 1a is accessible as an air sensitive solid soluble in alcohols
and halogenated solvents in which slow decomposition occurs.
Likewise the addition of one equivalent of 1 in toluene to a tol-
uene solution of one equivalent of Ir(CO)2Cl(p-tolNH2) afforded 1b
as a yellowish solid in yield of 10%. The application of Vaska’s com-
plex IrCl(CO)(PPh3)2 proved to increase yields but the product al-
ways contained the precursor in a ratio of about 1:1. Changing
the stoichiometry to 2:1 (1: IrCl(CO)(PPh3)2) produced neat yellow
[IrCl(CO){PhN(CH2PPh2)2}2] (1b) (Scheme 4). Treatment of 1b with
an excess of ammonium hexafluorophosphate in DCM/MeOH gave
pale yellow [Ir(CO){PhN(CH2PPh2)2}2]PF6 (1b0, Scheme 4). Both
compounds are soluble in halogenated solvents, acetone and alco-
hols, insoluble in hydrocarbons and diethyl ether.
13
Fig. 3. C{1H} NMR spectrum of 1c00.
well as for the four methylene protons supports the structures as
displayed in Schemes 2 and 3. Consequently in solution there is a
fast process which equilibrates the two different sides of the pseu-
do chair geometry of the six-membered chelate ring. Characteristic
multiplet patterns for chemically equivalent but magnetically
inequivalent nuclei are observed in the 13C{1H} NMR spectra of
the palladium and platinum complexes (Fig. 3).
The ESI-mass spectrum of 1a exhibits one main peak at m/z
1081 pointing to the molecular ion [Rh{PhN(CH2PPh2)2}2-Cl-CO]+
whereas in the ESI-mass spectrum of 1b the parent ion peaks for
the dechlorinated (m/z 1199, [Ir{PhN(CH2PPh2)2}2-Cl]+) and the
dechlorinated–decarbonylated species (m/z 1171, [Ir{PhN-
(CH2PPh2)2}2-Cl-CO]+) are observed. Thus the mass spectra of
Typically all carbon atoms directly connected to the phosphorus
nuclei give such patterns. The observation of an AXX0 pattern for
the cyanide carbon nuclei in 1c00 and 1d00 can be considered as
indicative for the cis coordination of the cyanide ligands. The cis
dicyano complexes 1c00 and 1d00 show strong IR absorption at
compounds 1a and 1b establish their compositions. The
m(CO)
absorptions in the IR spectra of 1a (1965 cmꢀ1), 1b (1932 cmꢀ1
)
and 1b0 (1931 cmꢀ1) are consistent with a d8-M(I)CO fragment
[15,21]. The 31P{1H} NMR spectra of the three trigonal bipyramidal
complexes differ considerably. At room temperature 1a displays a
sharp doublet, 1b two poorly resolved triplets and 1b0 two sharp
triplets (Table 2). The chemical exchange process which equili-
brates the axial and the equatorial phosphine groups is fast in
the rhodium complex 1a resulting in one resonance at 10 ppm
which is split by coupling with rhodium to a doublet (1JRhP = 130 -
Hz). The two observed triplets in the 31P{1H] NMR spectra of 1b
and 1b0 arise from the interaction of the two equivalent axial
m
(CN) = 2141 cmꢀ1 (1c00) and 2145 cmꢀ1 (1d00) which are well com-
parable to similar systems [43–45].
4.3. Rh(I) and Ir(I) complexes
Treatment of the rhodium precursor [Rh2(l-Cl)2(CO)4] with a
stoichiometric amount of 1 (ligand:rhodium ratio 2:1) in toluene

M. Stickel et al. / Polyhedron 46 (2012) 95–104
101
Table 1
Selected crystallographic data for compounds 1b0, 1c00, 2b, 4d and 5b.
1b0
1c00
2b
4d
5b
Empirical formula
Formula weight
Color and habit
Crystal dimensions
T (K)
C
65H58F6IrN2OP5
C34H29N3P2Pd
647.94
colorless plates
0.40 ꢂ 0.10 ꢂ 0.05
173(2)
C25H45ClIrNOP2
665.21
colorless columns
0.63 ꢂ 0.34 ꢂ 0.32
150(2)
C26H24Cl2P2PtS
696.44
colorless plates
0.51 ꢂ 0.21 ꢂ 0.07
100(2)
C38H80Cl2Ir2O2P4S2
1212.32
yellow columns
0.19 ꢂ 0.12 ꢂ 0.10
173(2)
1344.18
colorless columns
0.35 ꢂ 0.17 ꢂ 0.17
173(2)
Crystal system
Space group
Z
orthorhombic
Pbcn
4
monoclinic
P21/c
4
rhombohedral
R-3
18
monoclinic
P21/c
4
orthorhombic
P212121
4
a (Å)
b (Å)
c (Å)
18.9023(5)
22.7586(6)
15.7761(4)
90.00
6786.7(3)
1.316
9.7509(8)
19.4740(12)
16.4980(14)
106.979(6)
2996.2(4)
1.436
21.9014(18)
21.9014(18)
20.375(3)
90.00
12617.9(18)
1.576
10.7798(4)
17.4464(7)
13.5431(6)
91.6350(10)
2546.00(18)
1.817
12.0238(4)
14.8090(5)
27.0068(9)
90.00
4808.8(3)
1.675
b (°)
V (Å3)
Dcalc (g/cmꢀ3
)
l
(mmꢀ1
F (000)
)
2.140
2704
0.754
1320
4.988
6012
5.942
1352
5.890
2416
Reflections collected/
unique
93743/7445
[Rint = 0.0549]
99.4 (2h = 27.10°)
7445/0/360
39544/6344
[Rint = 0.1051]
98.5 (2h = 26.84°)
6334/0/361
35320/6658
[Rint = 0.1093]
95.5 (2h = 28.28°)
6658/0/280
50760/7737
[Rint = 0.0226]
99.5 (2h = 30.51°)
7737/84/290
138758/15221
[Rint = 0.0678]
99.8 (2h = 30.97°)
15221/38/463
Completeness to 2h
Data/restraints/
parameters
GOFa on F2
1.307
0.0496, 0.0795
0.0597, 0.0825
1.170
0.0524, 0.0863
0.0698, 0.0910
1.088
0.0285, 0.0722
0.0300, 0.0730
1.041
0.0138, 0.0334
0.0156, 0.0345
1.023
0.0209, 0.0407
0.0243, 0.0413
R1,
R1,
x
R2 [I > 2
r
(I)]b,c,d
xR2 (all data)
P
GOF ¼ ½ hklxhklfFo2ðhklÞ ꢀ ðFc2ðhklÞg2=ðn ꢀ pÞꢃ0:5, where n is the number of data and p the number of parameters.
a
b
c
P
P
R1
¼
hklkfFoðhklÞ ꢀ FcðhklÞgk= hkljFoðhklÞj.
P
P
2
2 0:5
x
R2 ¼ ½ hklxhklfF2oðhklÞ ꢀ ðFc2ðhklÞg =ð hklxhklfF2oðhklÞg ꢃ
.
P ¼ ½F2o þ 2F2c ꢃ=3, where a and b are constants adjusted by the program.
d
Table 2
Selected NMR and IR data for compounds 1b0, 1c00, 1d, 1d0, 1d00, 2b, 2d0, 4d and 5b.
Compound
1H [d]a (ppm)
2JHP (Hz)
31P{1H} [d]a (ppm)
J(P–P) (Hz)
J(P–M) (Hz)
IR (KBr) (cmꢀ1
)
CH2
m
(CO)/ (CN)
m
1
2
3
4
50
5
1a
1b
3.95 (d)
3.94 (d)
3.91 (d)c
3.24
4.6
2.0
0.9
3.0
9.8
0.9
–
ꢀ27.5 (s)
10.6 (s)
–
–
–
–
–
–
–
–
–
–
–
–
–
–/–
–/–
–/–
–/–
–/–
–/–
17.1 (s)c
ꢀ20.5 (s)
3.98 (d)d
2.79 (d)c
3.94 (s)
4.07 (br. m)
44.1 (s)d
20.9 (s)c
10.0 (d)
130.0
1965/–
1932/–
–
ꢀ31.0 (t, P1)f
ꢀ37.6 (t, P2)f
ꢀ32.1 (t)
ꢀ42.6 (t)
34.0f
34.0f
18.0
18.0
–
–
–
1b0
2.82 (m)b
3.60 (m)
3.92 (m)
4.43 (m)
4.08 (s)b
4.05 (d)
–
1931/–
1c00
1d
1d0
1d00
2a
–
ꢀ0.4 (s)b
ꢀ5.5 (s)
–
–
–
–
38.2
38.2
25.2
25.2
–
–
–/2141
–/–
–/–
–/2145
1994/–
2.6
2.4
1.8
2.6
3.2
3.0
3.5
2.2
3.0
–
3418.6
3362.6
2362.9
121.9
162.1
–
4.05 (d)
–6.5 (s)
4.09 (d)
ꢀ11.9 (s)
20.8 (dd, P1)c
61.0 (dd, P2)
14.5 (d, P1)c
30.3 (d, P2)
38.9 (s)
3.07 (d)c,e
3.13 (d)
2b
3.16 (d)c,e
3.25 (d)
1983/–
2c
2d0
3a
3.43 (d)
–
–/–
–/–
1987/–
3.56 (d)b
3.05 (br. s)c,e
3.12 (br. s)
3.16 (d)c,e
3.28 (d)
15.8 (s)b
–
3521.2
119.1
153.5
–
11.2 (dd, P1)c
39.2 (dd, P2)
5.0 (d)c
43.1
43.1
29.6
29.6
–
–
–
–
–
3b
3.4
3.1
–
2.1
5.0
10.9
10.4
1971/–
8.4 (d)
3c
3d
4d
5b
3.37 (s)b
3.43 (d)b
3.42 (d)b
3.17 (br. d)
3.44 (br. d)
28.9 (s)b
–
–/–
–/–
–/–
1960/–
4.9 (s)b
3454.6
3570.0
–
ꢀ7.3 (s)b
36.1(s)
a
b
c
d
e
f
d Value in CDCl3, at room temperature. Signal multiplicity in parentheses.
In CD2Cl2
In C6D6.
In D2O.
31P1H assignment by 31P1HHSQC.
At ꢀ60 °C.

102
M. Stickel et al. / Polyhedron 46 (2012) 95–104
Scheme 5. General synthetic route to unsymmetric complexes.
In the NMR spectra of the square planar complexes 2a, b and 3a,
b the number of resonances reflect the Cs symmetry of the mole-
cules. Due to the asymmetric coordinated metal centers the phos-
phorus atoms give rise to two sets of doublets in the 31P{1H} NMR
Scheme 4. Synthesis of 1a, 1b and 1b0.
phosphines with the two equatorial phosphines (Table 2). Interest-
ingly the presence of the chlorine ion supports the chemical ex-
change process so that the sample of 1b has to be cooled to
ꢀ60 °C to obtain two sharp triplets.
2
spectra (Table 2). The JPP coupling constants between 25.2 and
38.2 Hz are in the range for phosphines in mutual cis positions.
In case of 2a and 3a those resonances are split again into doublets
due to the coupling to 103Rh nuclei. The phosphorus atom trans to
the stronger trans influence ligand CO features the smaller
31P–103Rh coupling constant and is shifted to higher field. The 1H
and 13C{1H} NMR patterns agree in number and multiplicity with
the structure shown in Scheme 5.
The molecular structure in the solid state of [Ir(CO){PhN-
(CH2PPh2)2}2]PF6 (1b0) including selected interatomic distances
and angles is shown in Fig. 5. Its asymmetric unit consists of the
cation and anion with no unusual contacts between them. The
two PhN(CH2PPh2)2 ligands each form six-membered chelate rings
leaving the nitrogen atoms uncoordinated. The IrCP core has ideal-
ized C2v symmetry with a 2-fold axis along the Ir–C bond which is
comparable to the related arsenic compound [Ir(CO){PhAs
(CH2PPh2)2}2]PF6 [46]. The molecule can be viewed as trigonal-
bipyramidal with the atoms P2, P2a and C01 in the equatorial posi-
tions and P1 and P1a occupying the axial positions (Fig. 5, Table 1).
Therefore the P1–Ir1–P1a angle is almost linear (173.9°) and the
equatorial angles add up to 360.0°.
The X-ray structure of 2b shows the expected near square-
planar geometry [P2–Ir1–P1 95.94(2), P2–Ir1–C01 90.16(9), P1–
Ir1–Cl1 91.29(3), Cl1–Ir1–C01 82.57(9)] and comprises one chelat-
ing bisphosphine (2), one carbonyl and one chloro ligand (Fig. 6,
Table 1). The six-membered ring which is formed by the chelating
ligand generates an envelope conformation comparable to related
compounds [17,20].
A toluene suspension of bis(ditbutylphosphoniummethyl)sul-
fide dibromide (50) could be reacted directly with one equiv. of
each of triethylamine and Ir(CO)2Cl(p-tolNH2). Treatment of the
yellow reaction mixture with water followed by extraction of the
Heating a toluene solution of 2 or 3 with MCl(CO)(PPh3)2
(M = Rh, Ir) at 80 °C affords the crystalline air sensitive square pla-
nar rhodium complexes 2a, 3a and iridium complexes 2b, 3b
(Scheme 5). These compounds are soluble in benzene, toluene
and diethyl ether, insoluble in hydrocarbons. They decompose
when being exposed to halogenated solvents. The unsymmetrical
Ir(I) complexes 2b and 3b are less air-sensitive than their Rh(I)
counterparts (2a, 3a).
organic phase and removal of solvents gave yellow [Ir2Cl2(l-
{S(CH2PtBu2)2}2(CO)2] (5b, Scheme 6). The bimetallic complex 5b
Fig. 5. Molecular structure of 1b0. Thermal ellipsoids are drawn at 50% probability
level (phenyl substituents at P and N as well as hydrogen atoms are omitted for
clarity). Selected bond lengths (Å) and angles (°): P1–Ir1 2.349(7), Ir1–P1a 2.349(7),
P1–C13 1.846(4), C13–N14 1.473(5), N14–C15 1.464(5), C15–P2 1.858(3), P2–Ir1
2.359(4), P2a–Ir1 2.359(4), Ir1–C01 1.884(7), C01–O01 1.139(8), Ir1ꢁ ꢁ ꢁN14 3.924(3),
Ir1ꢁ ꢁ ꢁN14a 3.924(3); Ir1–P1–C13 117.9(1), P1–C13–N14 114.7(2), C13–N14–C15
113.4(3), N14–C15–P2 113.6(2), C15–P2–Ir1 112.8(1), P2–Ir1–P1 88.1(8), P1–Ir1–
P1a 173.9(5), P2–Ir1–P2a 102.4(4), P1–Ir1–P2a 95.6(2), P1a–Ir1–P2a 88.1(8), P1a–
Ir1–P2 95.6(2), P2–Ir1–C01 128.8(2), P1–Ir1–C01 87.0(2), P2a–Ir1–C02 128.8(2),
P1a–Ir1–C01 87.0(2).
Fig. 6. Molecular structure of 2b. Thermal ellipsoids are drawn at 50% probability
level (hydrogen atoms are omitted for clarity). Selected bond lengths (Å) and angles
(°): P1–Ir1 2.409(5), Ir1–P2 2.262(9), P2–C02 1.847(4), C02–N1 1.476(4), N1–C03
1.476(4), C03–P1 1.852(3), Ir1–C01 1.896(4), C01–O1 1.092(5), Ir1–Cl1 2.420(5),
Ir1ꢁ ꢁ ꢁN1 3.750(3); Ir1–P1–C03 114.8(1), P1–C03–N1 116.1(2), C03–N1–C02
110.4(2), N1–C02–P2 115.0(2), C02–P2–Ir1 115.9(1), P2–Ir1–P1 95.94(2), P2–Ir1–
Cl1 172.42(3), P2–Ir1–C01 90.16(9), P1–Ir1–C01 173.81(9), P1–Ir1–Cl1 91.29(3),
Cl1–Ir1–C01 82.57(9).

M. Stickel et al. / Polyhedron 46 (2012) 95–104
103
ligands. With an Ir1ꢁ ꢁ ꢁIr1 distance of 6.443(6) Å the separation is
too large for any direct interaction between the metal centers
[21]. Interatomic distances and angles are comparable to bimetallic
[Ir2Cl2(l-{PhAs(CH2PPh2)2}2(CO)2] [21].
5. Conclusion
Complexes of rhodium(I), iridium(I), palladium(II) and plati-
num(II) with the potentially tridentate ligands 1–4 have been pre-
pared. The nitrogen containing bisphosphines (1–3) coordinate
exclusively bidentate forming chelates via the phosphine func-
tions. Even if the steric demand is increased as in 2 and 3 the phos-
phines coordinate cis and avoid the bridging mode. Ligands 2 and 3
build square planar Rh(I) and Ir(I) complexes whereas two of the
corresponding bis(diphenylphosphine) 1 coordinate to one Rh(I)
and Ir(I) center generating trigonal bipyramidal compounds. This
is in contrast to the arsenic containing ligand system PhAs
(CH2PPh2)2 which acts as a bridging ligand in many examples.
Interestingly, in no case an interaction of the nitrogen donor with
any of the metals has been observed. Furthermore, bisphosphine 5
with sulfur incorporated into the ligand backbone acts as a
bridging ligand forming a 12-membered diiridamacrocycle (5b)
by coordination of the phosphine groups to Ir(I).
Scheme 6. Synthesis of 5b.
Acknowledgements
This work was funded by the German Ministry of Education Re-
search (BMBF), FKZ 13N10620. We thank Merck KGaA for gifts of
chemicals.
Fig. 7. Molecular structure of 5b. Thermal ellipsoids are drawn at 50% probability
level (hydrogen atoms are omitted for clarity). Selected bond lengths (Å) and angles
(°): P1–Ir1 2.337(9), Ir1–C5 1.865(3), C5–O5 0.965(4), Ir1–Cl1 2.425(9), Ir1–P4
2.335(9), P4–C4 1.853(3), C4–S2 1.811(3), S2–C3 1.816(3), C3–P3 1.857(2), P3–Ir2
2.344(5), Ir2–C6 1.855(4), C6–O6 1.019(5), Ir2–Cl2 2.383(1), Ir2–P2 2.339(8), P2–C2
1.852(3), C2–S1 1.817(3), S1–C1 1.814(3), C1–P1 1.857(3), C5–O5 0.965(4), C6–O6
1.019(5), Ir1ꢁ ꢁ ꢁIr2 6.443(6); Ir1–P1–C1 110.35(8), P1–C1–S1 114.2(1), C1–S1–C3
97.0(1), S1–C2–P2 114.8(1), C2–P2–Ir2 110.73(8), P2–Ir2–P3 169.85(2), Ir2–P3–C3
110.09(8), P3–C3–S2 113.1(1), C3–S2–C4 97.6(1), S2–C4–P4 114.5(1), C4–P4–Ir1
110.92(8), P4–Ir1–C5 88.1(1), P4–Ir–Cl1 92.22(2), P4–Ir1–P1 171.00(2), C5–Ir1–Cl1
167.8(1), P1–Ir1–C5 88.1(1), P1–Ir1–Cl1 93.19(2), P2–Ir2–P3 169.85(2), P2–Ir2–C6
89.9(1), P2–Ir2–Cl2 91.83(2), C6–Ir2–Cl2 166.8(1).
Appendix A. Supplementary data
CCDC 883670–883678 contains the supplementary crystallo-
graphic data for 1b0, 1c00, 1d, 1d0, 1d00, 2b, 2d0, 4d and 5b. These data
can be obtained free of charge via http://www.ccdc.cam.ac.uk/con-
ts/retrieving.html, or from the Cambridge Crystallographic Data
Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-
336-033; or e-mail: deposit@ccdc.cam.ac.uk. Crystallographic data
for compounds 1d, 1d0, 1d00 and 2d0 see supporting information.
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.poly.2012.07.083.
is moderately soluble in aromatic solvents. Halogenated solvents
lead to decomposition.
The macrocycle 5b shows one main ion peak at m/z 1175. Its
composition has also been confirmed by elemental analysis. The
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