Aminophosphines derived from morpholine and N-methylpiperazine: Synthesis, oxidation reactions and transition metal complexes

Article abstract of DOI:10.1016/j.poly.2006.05.041

The synthesis, derivatization and coordination behavior of N-diphenylphosphinomorpholine (1) and N-diphenylphosphinopiperazine (2) is described. Ligands 1 and 2 react with elemental sulfur or selenium to give the corresponding chalcogenides in good yield.

Full text of DOI:10.1016/j.poly.2006.05.041

Polyhedron 25 (2006) 3215–3221
www.elsevier.com/locate/poly
Aminophosphines derived from morpholine and N-methylpiperazine:
Synthesis, oxidation reactions and transition metal complexes
a,
a
a
b
Maravanji S. Balakrishna *, D. Suresh , Paulose P. George , Joel T. Mague
a
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
b
Department of Chemistry, Tulane University, New Orleans, LA 70118, USA
Received 21 May 2006; accepted 26 May 2006
Available online 27 June 2006
Abstract
The synthesis, derivatization and coordination behavior of N-diphenylphosphinomorpholine (1) and N-diphenylphosphinopiperazine
(2) is described. Ligands 1 and 2 react with elemental sulfur or selenium to give the corresponding chalcogenides in good yield. Reaction
of 1 with paraformaldehyde leads to the insertion of methylene into P–N bond to give phosphine oxide, Ph2P(O)CH2NC4H8O in quan-
titative yield. Treatment of 2 with [Pd(COD)Cl2] produces both the mononuclear [PdCl2{(Ph2PNC4H8O)-jP}2] and the chloro-bridged
dinuclear complex, [(OC4H8NPh2P)Pd-(l-Cl)Cl]2 whereas the similar reaction of 2 with [Pt(COD)Cl2] affords only the mononuclear
complex [PtCl2{(Ph2PNC4H8O)-jP}2]. Interestingly, ligand 2 reacts with Mo(0), W(0), Ru(II), Pd(II), Pt(II) and Au(I) derivatives to
furnish exclusively mononuclear complexes. The molecular structures of Ru(II) and Pd(II) dimer have been confirmed by X-ray
studies.
ꢀ 2006 Elsevier Ltd. All rights reserved.
Keywords: Aminophosphines; Insertion reaction; Sulfur and selenium derivatives; Palladium and platinum complexes; Ruthenium(II)
1. Introduction
In this context, tertiaryphosphines with amine func-
tionalities have drawn considerable interest as ligands
[4], and their platinum metal complexes [5], have shown
excellent catalytic properties in a variety of organic trans-
formations [6], including various polymerization reactions
[7]. This is due to the multiple bonding nature of P–N
bonds which can readily alter the electronic properties
of phosphorus(III) center thus influencing its coordinating
abilities and hence the catalytic properties. Further, the
electronic properties vary with nitrogen substituents.
Although phosphines containing morpholine and piperi-
dine moieties have been prepared, derivatized [8], and
employed in catalytic studies [9], the reports on coordina-
tion chemistry is scant. As a part of our continued interest
in developing phosphine based ligand systems for transi-
tion metal chemistry [10], and catalytic applications
[5a,11], we report in this paper some transition metal
complexes of phosphines containing morpholine and N-
methylpiperazine.
There has been large interest in the use of hybrid ligands
or hemi labile ligands having both hard and soft donor cen-
ters. These hemi labile ligands form weak metal–oxygen [1],
metal–sulfur [2], or metal–nitrogen bonds [3], while phos-
phorus atom can strongly coordinate to the metal centers.
The hard centers in these hemi labile ligands may behave
as intramolecular solvent molecules stabilizing the empty
coordination site and due to chelate effect these complexes
are much more stable than simple solvent adducts. Such
systems would be ideal for homogeneous catalysis, since
the more labile donor center can readily dissociate from
the metal, thus facilitating a vacant coordination site, which
can produce an active intermediate in catalytic process.
*
Corresponding author. Tel.: +91 22 2576 7181; fax: +91 22 2572 3480/
2576 7152.
E-mail address: krishna@chem.iitb.ac.in (M.S. Balakrishna).
0277-5387/$ - see front matter ꢀ 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2006.05.041

3216
M.S. Balakrishna et al. / Polyhedron 25 (2006) 3215–3221
2. Results and discussion
[M(CO)4(PPh2NC4H8NMe)2] (11, M = Mo; 12, M = W).
The 31P NMR spectra of 11 and 12 exhibit single reso-
The reactions of two equivalents of morpholine or N-
methylpiperazine with diphenylchlorophosphine in diethyl
ether at room temperature afford the corresponding deriv-
atives N-diphenylphosphinoamines Ph2PNC4H8O (1) and
Ph2PNC4H8NMe (2) in good yield. Similarly, the reaction
of four equivalents of morpholine with PhPCl2 afforded
bis(morpholino)phenylphosphine PhP(NC4H8O)2 (3). Both
the morpholine and N-methylpiperazine derivatives (1–3)
react smoothly with elemental sulfur or selenium in toluene
under reflux conditions to give the corresponding sulfide or
selenide derivatives 4–9 as air stable solids. The prepara-
tion of some of these chalcogen derivatives have been
reported previously but without all the details [12]
nances at 106.2 and 80.8 ppm with tungsten complex show-
ing tungsten satellites with a JWP coupling of 304.4 Hz
1
which confirms the mutual trans dispositions of two phos-
phine ligands [10f]. Further confirmation for the trans
geometry of complexes 11 and 12 comes from IR spectra
which show single absorption for mCO at 1888 and
1895 cmꢀ1, respectively, characteristic of complexes con-
taining trans-M(CO)4 moieties [14].
The ruthenium-arene dimer, [(p-cymene)RuCl2]2 reacts
with two equivalents of 2 in dichloromethane at room
temperature to produce an orange-red complex
[(g6-C10H14)RuCl2{PPh2NC4H8NMe}] (13) in quantitative
yield. The 31P NMR spectrum of 13 shows a single reso-
nance at 73.5 ppm with a coordination shift of 12 ppm.
The mass spectrum of 13 exhibits parent ion peak
(M + 1) at 591.3. The structure of complex 13 was further
confirmed by single crystal X-ray diffraction study.
O
N
N
PPh2
PPh
N PPh2
O
N
Me N
O
2.1. Structure of [(g6-C10H14)RuCl2{PPh2NC4H8NMe}]
(13)
1
2
3
The 31P{1H} NMR spectra of compounds 1–3 show sin-
Perspective view of the molecular structure of the com-
pound 13 with the atomic numbering scheme is shown in
Fig. 1 along with selected bond lengths and bond angles.
The details of the structure determination are given in
Table 1.
gle resonances at 61.7, 63.3 and 95.8 ppm, respectively,
whereas their chalcogenides 4–9 show single resonance in
the range of 65–79 ppm. The mono-morpholine and N-
1
methylpiperazine derivatives 7 and 8 show JPSe coupling
The coordination geometry around the ruthenium cen-
ter in 13 can be best described as pseudo octahedral
three-legged piano stool, typically of half-sandwich com-
around 760 Hz whereas the bis(morpholine) derivative 9
1
1
shows a JPSe coupling of 788 Hz. The H NMR spectral
data of 1–9 are consistent with the structures proposed.
The structural composition of all compounds has been con-
firmed by elemental analysis.
˚
plexes. The P–N (1.680(2) A) bond is shorter than the
The reaction of N-diphenylphosphinomorpholine 1 with
paraformaldehyde in toluene under reflux conditions lead
to methylene inserted product 10 in good yield. The meth-
ylene insertion reaction proceeds in accordance with our
reports on similar aminophosphines [10e,13]. The 31P
NMR spectrum of 10 shows a singlet at 28.4 ppm. The
1H NMR spectrum of compound 10 exhibits two types of
resonances for the alkyl (NC4H8O and CH2) protons apart
from aryl protons. The NC4H8O protons appear at
3.80 ppm and CH2 protons appear at 3.42 ppm. In the
mass spectrum (MS), the most intense fragment ion
appears at m/e 302 [M+ + 1] which is the expected molec-
ular ion.
The reactions of 2 with either M(CO)6 or cis-
W(CO)4(piperidine)2 under refluxing conditions produce
the trans-tetracarbonyl complexes of the type trans-
Me
N
CO
CO
Fig. 1. Molecular structure of 13. For clarity, solvent and all hydrogen
P
M
P N
atoms have been omitted. Thermal ellipsoids are drawn at 50% proba-
N Ph2
Ph2
CO
˚
bility. Selected bond distances (A): Ru–Cl(1), 2.4031(7); Ru–Cl(2),
O
N
Me
CO
P
Ph2
2.4095(6); Ru–P, 2.3356(6); P–N(1), 1.680(2); N(1)–C(13), 1.471(3);
N(2)–C(17), 1.448(3). Selected bond angles (ꢁ): Cl(1)–Ru–Cl(2), 86.83(2);
Cl(1)–Ru–P, 84.78(2); Cl(1)–Ru–C(19), 150.28(6); Cl(2)–Ru–P, 87.25(2).
N
11 M = Mo
12 M = W
O
10
11

M.S. Balakrishna et al. / Polyhedron 25 (2006) 3215–3221
3217
The 31P{1H} NMR spectra of 14 show a single reso-
nance at 75.4 ppm. In the mass spectrum (MS) the expected
molecular ion appears at m/e 862 [M ꢀ Cl]. The structure
of 14 was confirmed by a single crystal X-ray diffraction
study. The 31P{1H} NMR spectra of 15 and 16 exhibit sin-
gle resonances at 67.3 and 68.5 ppm, respectively. The
phosphorus-31 chemical shifts due to the corresponding
platinum derivatives (17 and 18) are relatively shielded
and appear at 50.7 and 50.2 ppm, respectively. Both the
complexes show large JPtP coupling (17, 3968 Hz; 18,
3965 Hz) which is characteristic of phosphines having
mutually cis-dispositions [16].
The gold(I) complex, [ClAu(PPh2NC4H8NMe)] (19) was
produced in the reaction between 2 and AuCl(SMe2) as col-
orless light sensitive solid soluble in most of the organic
solvents. The 31P NMR spectrum of 19 shows a single res-
onance at 77.9 ppm with a coordination shift of 16.5 ppm.
Table 1
Crystallographic data for complexes 14 and 13
Formula
M
C32H36Cl4N2O2P2Pd2 C27H35Cl2N2PRu Æ CH2Cl2
897.2
675.44
Crystal size (mm)
Crystal system
Space group
0.08 · 0.09 · 0.13
monoclinic
C21/c
17.3015(9)
8.3673(4)
23.6400(1)
90
95.91(1)
90
3404.1(3)
4
0.09 · 0.12 · 0.19
triclinic
ꢀ
P1 ðNo: 2Þ
˚
a (A)
11.7680(10)
11.8570(10)
11.9230(10)
67.78(1)
76.59(1)
72.59(1)
1456.3(2)
2
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
1
3
˚
V (A )
Z
Dcalc (g cmꢀ3
)
1.751
1.540
l (mmꢀ1
T (K)
)
1.498
0.981
293
100
hmin,max (ꢁ)
Total number of
1.7, 28.3
14700
2.2, 28.4
25781
reflections
Number of unique 4106
reflections
7177
2.2. Structure of [Pd2Cl2(l-Cl2){Ph2P(NC4H8O)}2] (14)
Rint
R
0.031
0.0373
0.0833
0.025
0.0315
0.0747
Perspective view of the molecular structure of the com-
pound 14 with the atomic numbering scheme is shown in
Fig. 2 along with selected bond lengths and bond angles.
The Pd2Cl2 plane is perpendicular to morpholine rings.
The Cl(1)–Pd–P angle is 93.35(3)ꢁ where as Cl(1_a)–Pd–
Cl(2) angle is 89.61(3)ꢁ which clearly indicates some distor-
tion at the metal center. The Cl(1)–Pd–P angle (93.35(3)ꢁ)
appears to have increased from the squareplanar value of
90ꢁ to an extent limited by the development of phos-
R0
˚
normally accepted value for a single bond (1.77 A), but it
compares well with those found in a variety of phospho-
rus(III)–nitrogen compounds suggesting a degree of P–N
multiple bonding. Similarly, the Ru–P bond distance is
(2.336(1) A) comparable with those observed in ruthenium
complexes containing a variety of tertiary phosphines. The
˚
˚
phine–chloride interactions. The Pd–Cl(1) (2.32 A) bond
˚
˚
distance is slightly longer than Pd–Cl(2) (2.27 A) bond dis-
average Ru–Cl bond distance is 2.403(1) A.
tance. That there is only a single 31P NMR resonance in
solution suggests that the observed difference may result
from packing (or) other solid state effects.
Treatment of Pd(COD)Cl2 with one equivalent of
ligand 1 in dichloromethane, afforded a chloro-bridged
dinuclear complex, [Pd2Cl2(l-Cl2){Ph2P(NC4H8O)}2] (14).
The reaction of two equivalents of 1 with Pd(COD)Cl2
in dichloromethane afforded mononuclear complex, cis-
[PdCl2{Ph2PNC4H8O}2] (15) as a major product contain-
ing small quantities of dinuclear complex, 14 [15] which
are separated by fractional crystallization. Surprisingly,
Pd(COD)Cl2 on treatment with 2 produced exclusively
the cis-[PdCl2{PPh2NC4H8NMe}2] (16) as a major prod-
uct irrespective of the stoichiometry of the reactants and
the reaction conditions
X
Me
O
Ph2
Cl
N
Cl
Cl
N
N
N
Ph2
P
Pd
Pd
P
PPh2
N
Ph
P
N
2
X
P
M
Cl
Ph2
Au
Cl
Cl
Cl
O
19
14
15 M = Pd; X = O
16 M = Pd; X = NMe
17 M = Pt; X = O
18 M = Pt; X= NMe
In contrast, the reaction of either one or two equivalents
Fig. 2. Molecular structure of 14. For clarity, solvent and all hydrogen
atoms have been omitted. Thermal ellipsoids are drawn at 50% proba-
bility. Selected bond distances (A): Pd–Cl(1), 2.325(8); Pd–Cl(2), 2.271(1);
Pd–P, 2.215(1); Pd–Cl(1a), 2.437(1); P–N, 1.676(3); P–Cl, 1.808(3); P–
C(7), 1.804(3). Selected bond angles (ꢁ): Cl(1)–Pd–Cl(2), 171.39(3); Cl(1)–
Pd–P, 93.35(3); Cl(1)–Pd–C(11a), 86.80(3); Cl(2)–Pd–P, 89.73(5); Pd–P–N,
113.46(9).
of ligand 1 or 2 with Pt(COD)Cl2 afforded only the mono-
nuclear complexes, cis-[PtCl2{Ph2PNC4H8X}2] (17, X = O;
18, X = NMe) in good yield. Further attempts to synthe-
size a dinuclear platinum complex analogues to the dipalla-
dium complex 14 have been unsuccessful.
˚

3218
M.S. Balakrishna et al. / Polyhedron 25 (2006) 3215–3221
3. Experimental
3.3. Preparation of PhP(NC4H8O)2 (3)
All experimental manipulations were carried out under
an atmosphere of dry nitrogen or argon using Schlenk tech-
niques. All the solvents were purified by conventional pro-
cedures and distilled prior to use. The metal precursors
[W(CO)4(pip)2] [17], [(p-cymene)RuCl2]2 [18], [AuCl-
(SMe2)] [19], [(COD)PdCl2], [(COD)PtCl2] [20] are pre-
pared according to the literature methods and [Mo(CO)6]
was obtained from Aldrich chemicals.
A solution of HNC4H8O (1.73 g, 19.93 mmol) in dry
diethyl ether (20 mL) was added drop wise to chlorodiphe-
nylphosphine (2 g, 9.06 mmol) also in diethyl ether (70 mL)
at 0 ꢁC with vigorous stirring. Then the solution was allowed
to warm to room temperature and stirring was continued for
24 h. The morpholine hydrochloride was removed by filtra-
tion. The solvent was removed under vacuum to give a white
solid of the crude product, which was crystallized from
dichloromethane/petroleum ether (2:1). Yield: 91.0%
(2.95 g); m.p. 98–100 ꢁC. Anal. Calc. for C14H21N2O2P: C,
59.98; H, 7.51; N, 9.94. Found: C, 59.02; H, 7.24; N,
9.27%. 31P{1H} NMR (300 MHz, CDCl3): d 95.8 (s).
The 1H and 31P NMR (d in ppm) spectra were obtained
on a VXR300S spectrometer operating at frequencies of
300 and 121 MHz, respectively. The spectra were recorded
in CDCl3 solutions with CDCl3 as an internal lock; TMS
1
and 85% H3PO4 were used as external standards for H
and 31P{1H} NMR, respectively. Positive shifts lie down-
field of the standard in all cases. Melting points of all com-
pounds were determined on Veego melting point apparatus
and were uncorrected. Mass spectra were recorded on
MASPEC (msco/9849) system. Microanalyses were carried
out on a Carlo Erba model EA 1112 elemental analyzer.
3.4. Preparation of Ph2P(S)(NC4H8O) (4)
A mixture of compound 1 (0.5 g, 1.8 mmol) and sulfur
(0.06 g, 1.8 mmol) in toluene (10 mL) was heated under
reflux for 12 h to give a clear solution. Solvent was removed
under reduced pressure to give a white residue. The residue
was dissolved in CH2Cl2 (5 mL), layered with 1 mL of
petroleum ether and kept at room temperature to give col-
orless crystals of 3. Yield: 90% (0.49 g); m.p. 116–118 ꢁC
(decomp.). Anal. Calc. for C16H18NOPS: C, 63.32; H,
5.98; N, 4.61; S, 10.57. Found: C, 63.61; H, 5.99; N, 4.92;
S, 8.74%. 31P{1H} NMR (300 MHz, CDCl3): d 65.9 (s).
3.1. Preparation of Ph2P(NC4H8O) (1)
A solution of HNC4H8O (1.73 g, 19.93 mmol) in dry
diethyl ether (20 mL) was added drop wise to a chlorodi-
phenylphosphine (2 g, 9.06 mmol) also in diethyl ether
(70 mL) at 0 ꢁC with vigorous stirring. Then the solution
was allowed to room temperature and stirring was contin-
ued for 24 h. The morpholine hydrochloride was removed
by filtration. The solvent was removed under vacuum to
give a white solid of the crude product, which was crystal-
lized from dichloromethane/petroleum ether (b.p. 60–
80 ꢁC) (2:1). Yield: 89% (2.20 g); m.p. 84–85 ꢁC. Anal. Calc.
for C16H18NOP: C, 70.83; H, 6.68; N, 5.16. Found: C,
3.5. Synthesis of [P(S)Ph2NC4H8NMe] (5)
As for 4, using Ph2PNC4H8NMe (0.19 mg, 67.5 mmol)
and elemental sulfur (0.022 mg, 67.6 mmol). Yield: 95%
(0.202 g); m.p. 106–108 ꢁC. Anal. Calc. for C17H21N2PS:
C, 64.53; H, 6.69; N, 8.85; S, 10.13. Found: C, 63.92; H,
1
6.45; N, 8.31; S, 9.6%. H NMR (400 MHz, CDCl3): d
1
70.02; H, 6.32; N, 5.06%. H NMR (300 MHz, CDCl3): d
2.98 (s, 4H, CH2), 2.38 (s, 4H, CH2), 2.2 (s, 3H, NMe),
8.1 (m, 5H, phenyl), 7.25 (m, 5H, phenyl). 31P{1H} NMR
(400 MHz, CDCl3): d 65.8 (s).
7.23–7.59 (m, 10H, Ph), d 3.71 (t, 4H, OC2H4), d 3.07 (tt,
4H, NC2H4). 31P{1H} NMR (300 MHz, CDCl3): d 63.7 (s).
3.2. Preparation of [Ph2PNC4H8NMe] (2)
3.6. Preparation of PhP(S)(NC4H8O)2 (6)
To an ice cooled solution of N-methylpiperazine (2.26 g,
22.5 mmol) in diethyl ether (50 mL), a solution of chloro-
diphenylphosphine (2.48 g, 11.25 mmol) in diethyl ether
(30 mL) was added dropwise over a period of 15 min with
constant stirring. The reaction mixture was allowed to
warm to room temperature and stirring was continued
for 16 h. The piperazinehydrochloride was filtered off and
the filtrate was dried under vacuum. The residue obtained
was dissolved in 20 mL of acetonitrile and the solution
was cooled to ꢀ25 ꢁC for 10 h to give analytically pure
product of 1 as colorless blocks. Yield: 70% (2.24 g); m.p.
58–60 ꢁC. Anal. Calc. for C17H21N2P: C, 71.81; H, 7.44;
As for 4, using PhP(NC4H8O)2 (1 g, 3.56 mmol) and sele-
nium powder (0.15 g, 3.56 mmol). Yield: 92% (1 g); m.p.
120–122 ꢁC. Anal. Calc. for C14H21N2O2PS: C, 53.83; H,
6.77; N, 8.99; S, 10.26. Found: C, 53.70; H, 6.68; N, 9.18;
S, 8.85%. 31P{1H} NMR (300 MHz, CDCl3): d 74.8 (s).
3.7. Preparation of Ph2P(Se)(NC4H8O) (7)
A mixture of 1 (1 g, 3.68 mmol) and selenium powder
(0.29 g, 3.68 mmol) in toluene (25 mL) was heated under
reflux for 12 h. The solution was then cooled to 25 ꢁC
and filtered to remove any undissolved selenium. The sol-
vent was removed under reduced pressure to give a sticky
residue. The residue was dissolved in 3 mL of CH2Cl2, lay-
ered with 1 mL of petroleum ether and kept at room tem-
perature to afford crystals of 5. Yield: 92% (0.12 g); m.p.
1
N, 9.85. Found: C, 71.31; H, 7.22; N, 9.91%. H NMR
(400 MHz, CDCl3): d 2.98 (s, 4H, CH2), 2.38 (s, 4H,
CH2), 2.20 (s, 3H, NMe), 7.30–7.55 (m, 10H, phenyl).
31P{1H} NMR (400 MHz, CDCl3): d 61.3 (s).

M.S. Balakrishna et al. / Polyhedron 25 (2006) 3215–3221
3219
120–122 ꢁC. Anal. Calc. for C16H18NOPSe: C, 54.86; H,
NMe), 7.4 (m, 5H, phenyl), 7.1 (m, 5H, phenyl). 31P{1H}
NMR (400 MHz, CDCl3): d 106.2 (s).
1
5.17; N, 3.99. Found: C, 55.3; H, 5.2; N, 4.4%. H NMR
(300 MHz, CDCl3): d 8.12–7.2.1 (m, 21H, Ph), d 3.77 (tt,
4H, OC2H4), d 2.82 (tt, 4H, NC2H4). 31P{1H} NMR
(300 MHz, CDCl3): d 66.9 (s), JPSe = 760 Hz.
3.12. Preparation of trans-[W(CO)4{(Ph2PNC4H8NMe)-
jP}2] (12)
1
3.8. Preparation of [P(Se)Ph2NC4H8NMe] (8)
As for 11 using [Ph2PNC4H8NMe] (0.053 mg,
188 mmol) and [W(CO)4(pip)2] (0.044 g, 94 lmol). Yield:
68% (0.055 g); m.p. 178–180 ꢁC (dec). Anal. Calc. for
C38H42O4N4P2W: C, 52.79; H, 4.89; N, 6.48. Found: C,
As for 7 using Ph2PNC4H8NMe (0.230 g, 80.9 mmol)
and grey selenium (0.064 g, 80.9 mmol). Yield: 90%
(261 mg); m.p. 114–116 ꢁC. Anal. Calc. for C17H21N2PSe:
C, 56.20; H, 5.83; N, 7.71. Found: C, 56.37; H, 5.46; N,
1
53.23; H, 5.09; N, 6.65%. H NMR (400 MHz, CDCl3): d
2.82 (s, 4H, CH2), 2.43 (s, 4H, CH2), 2.10 (s, 3H, NMe),
7.61–7.24 (m, 10H, phenyl). IR (KBr disc) cmꢀ1: mCO at
1890 s. 31P{1H} NMR (300 MHz, CDCl3): d 80.8 (s),
1JPW = 304.4 Hz.
1
7.29%. H NMR (400 MHz, CDCl3): d 2.9 (s, 4H, CH2),
2.5 (s, 4H, CH2), 2.3 (s, 3H, NMe), 8.2 (m, 5H, phenyl),
7.5 (m, 5H, phenyl). 31P{1H} NMR (400 MHz, CDCl3): d
1
66.28 (s), JPSe = 758.4 Hz.
3.13. Preparation of [Ru(g6-C10H14)Cl2{(PPh2NC4H8-
NMe)-jP}] (13)
3.9. Preparation of PhP(Se)(NC4H8O)2 (9)
As for 7 using PhP(NC4H8O)2 (1 g, 3.68 mmol) and sele-
nium powder (0.29 g, 3.68 mmol). Yield: 78% (1 g); m.p.
120–122 ꢁC. Anal. Calc. for C14H21N2O2PSe: C, 46.86; H,
5.58; N, 7.79. Found: C, 46.8; H, 5.34; N, 8.04%. 1H
NMR (300 MHz, CDCl3): d 7.98–7.26 (m, 5H, Ph), d
3.66 (tt, 4H, OC2H4), d 3.07 (tt, 4H, NC2H4). 31P{1H}
A solution of [(p-cymene)RuCl2]2 (0.033 mg, 54.5 lmol)
in dichloromethane (5 mL) was added dropwise to a solu-
tion of 2 (0.031 mg, 109 lmol) in the same solvent (5 mL)
at room temperature. After the completion of the addition,
the reaction mixture was stirred for 4 h and the solvent was
removed under reduced pressure. The residue obtained was
washed with diethyl ether to give analytically pure product
of 13 as red micro crystalline solid. Yield: 85% (55 mg);
m.p. 168–170 ꢁC (dec). Anal. Calc. for C27H35N2PRuCl2:
C, 54.91; H, 5.97; N, 4.74. Found: C, 54.63; H, 5.74; N,
1
NMR (300 MHz, CDCl3): d 78.2 (s), JPSe = 788 Hz.
3.10. Preparation of Ph2(O)PCH2NC4H8O (10)
1
A mixture of 1 (0.2 g, 0.73 mmol) and paraformalde-
hyde (0.02 g, 0.81 mmol) in toluene (6 mL) was heated at
100 ꢁC with stirring for 12 h. The solution was then cooled
to 25 ꢁC and filtered to remove any undissolved impurities.
The compound was crystallized from CH2Cl2–n-hexane
(4:1). Yield: 81% (0.18 g); m.p. 136–138 ꢁC. Anal. Calc.
for C17H20N02P: C, 67.76; H, 6.69; N, 4.64. Found: C,
4.07. H NMR (400 MHz, CDCl3): d 7.70–7.43 (m, 10H,
phenyl), 5.15 (d, JHH = 6.4 Hz, 2H, Cymene phenyl), 4.95
(d, JHH = 6.4 Hz, 2H, Cymene phenyl), 3.1 (s, 3H, NMe),
2.75 (septet, 1H, CH), 2.5 (s, 4H, CH2) 2.4 (s, 4H, CH2),
1.95 (s, 3H, CH3). 31P{1H} NMR (300 MHz, CDCl3): d
73.5 (s).
1
66.78; H, 6.79; N, 4.62%. H NMR (300 MHz, CDCl3): d
3.14. Preparation of [Pd2(l-Cl)2Cl2{(Ph2PNC4H8O)-
jP}2] (14)
7.85–7.26 (m, 10H, Ph), d 3.72 (t, 4H, OC2H4), d 3.42 (d,
2
2H, CH2, JPH = 6 Hz), d 2.85 (s, 4H, NC2H4). 31P{1H}
NMR (300 MHz, CDCl3): d 28.4 (s). MS (FAB): 302
To a mixture of Pd(COD)Cl2 (0.05 g, 0.17 mmol) and
compound 1 (0.05 g, 0.17 mmol) a CH2Cl2 solution
(8 mL) was added and the resultant reaction mixture was
stirred at room temperature for 48 h. The solution was con-
centrated to 3 mL and 1 mL of petroleum ether was added.
Cooling this solution to 0 ꢁC gave 8 as red crystals.
Yield: 77% (0.06 g); m.p. 160–162 ꢁC. Anal. Calc. for
C32H36Cl4N2O2P2Pd2: C, 42.83; H, 4.04; N, 3.12. Found:
(M+ + 1).
3.11. Preparation of trans-[Mo(CO)4{(Ph2PNC4H8NMe)-
jP}2] (11)
A mixture of 2 (0.044 g, 0.153 mmol) and [Mo(CO)6]
(20.22 mg, 0.076 mmol) in toluene (15 mL) was heated at
90 ꢁC for 10 h. The yellow solution obtained was cooled
to room temperature and passed through a column con-
taining celite and the solvent was removed under vacuo.
The pale yellow micro crystalline residue obtained was
washed twice with diethyl ether (3 mL) to afford analyti-
cally pure product of 11. Yield: 70% (41 mg); m.p. 186–
188 ꢁC (dec). Anal. Calc. for C38H42O4N4P2Mo: C, 58.77;
H, 5.45; N, 7.21. Found: C, 57.69; H, 5.42; N, 6.38%. FT
1
C, 42.6; H, 3.7; N, 3.5%. H NMR (300 MHz, CDCl3): d
7.26–8.05 (m, 10H, Ph), d 3.68 (t, 4H, OC2H4), d 3.13 (tt,
4H, NC2H4). 31P{1H} NMR (300 MHz, CDCl3): d 75.4
(s). MS (FAB): 862 (M ꢀ Cl).
3.15. Preparation of cis-[PdCl2{(PPh2NC4H8O)-jP}2]
(15)
1
IR (KBr disc) cmꢀ1: mCO at 1888 s. H NMR (400 MHz,
To a mixture of Pd(COD)Cl2 (0.05 g, 0.17 mmol) and
CDCl3): d 3.2 (s, 4H, CH2), 2.4 (s, 4H, CH2), 2.2 (s, 3H,
compound 1 (0.11 g, 0.35 mmol) a CH2Cl2 solution

3220
M.S. Balakrishna et al. / Polyhedron 25 (2006) 3215–3221
(8 mL) was added and the resultant reaction mixture was
stirred at room temperature for 48 h. The solution was con-
centrated to 3 mL and 1 mL of petroleum ether was added.
Cooling this solution to 0 ꢁC gave 9 as red crystalline mate-
rial. Further cooling the remaining solution gave 9 as yel-
low crystals. Yield: 61% (0.08 g); m.p. 180–185 ꢁC. Anal.
Calc. for C32H36Cl2N2O2P2Pd: C, 53.38; H, 5.04; N, 3.91.
of 2 (0.030 g, 88.8 lmol) also in dichloromethane (8 mL) at
room temperature and the reaction mixture was stirred for
4 h. The solvent was removed under reduced pressure and
the residue was washed with diethyl ether to give analyti-
cally pure product of 19 as white micro crystalline solid.
Yield: 96% (41 mg); m.p. 150–152 ꢁC (dec). Anal. Calc.
for C17H21N2PAuCl: C, 39.51; H, 4.09; N, 5.42. Found:
C, 38.96; H, 3.85; N, 4.92%. 1H NMR (400 MHz, CDCl3):
3.24 (s, 4H, CH2), 2.43 (s, 4H, CH2), 2.21 (s, 3H, NMe),
7.71–7.50 (m, 10H, phenyl). 31P{1H} NMR (400 MHz,
CDCl3): d 77.9 (s).
1
Found: C, 52.82; H, 5.36; N, 3.72%. H NMR (300 MHz,
CDCl3): d 7.71–7.27 (m, 10H, Ph), d 3.64 (t, 4H, OC2H4),
d 3.01 (tt, 4H, NC2H4). 31P{1H} NMR (300 MHz, CDCl3):
d 67.3 (s).
3.16. Preparation of cis-[PdCl2{(PPh2NC4H8NMe)-jP}2]
(16)
4. X-ray crystallography
Crystals of compounds 13 and 14 suitable for X-ray
crystal analysis were mounted on Cryoloopse with Par-
atone oil and placed in the cold nitrogen stream of the Bru-
ker Kryoflexe attachment of the Bruker APEX CCD
diffractometer. Full spheres of data were collected using
606 scans in x (0.3ꢁ per scan) at 0ꢁ, 120ꢁ and 240ꢁ and
graphite-monochromated Mo Ka radiation (k = 0.71073
As for 15, using [Pd(COD)Cl2] (25 mg, 88 lmol) and 2
(50 mg, 175 lmol). Yield: 95% (62 mg); m.p. 150–152 ꢁC
(dec). Anal. Calc. for C34H42Cl2N4P2Pd: C, 54.74; H,
5.67; N, 7.51. Found: C, 53.68; H, 5.38; N, 7.32%. 1H
NMR (400 MHz, CDCl3): d 3.1 (s, 4H, CH2), 2.5 (s, 4H,
CH2), 2.2 (s, 3H, CH2), 7.71–7.42 (m, 10H, phenyl).
31P{1H} NMR (400 MHz, CDCl3): d 68.5 (s).
2
˚
A). The raw data were reduced to F values at a resolution
˚
of 0.75 A using the SAINT+ software (SAINT+, V. 6.35A,
Bruker-AXS, Madison, WI, 2002) and global refinements
of unit cell parameters using 5000–9000 reflections chosen
from the full sets of data were performed. Multiple
measurements of equivalent reflections provided the basis
for empirical absorption corrections as well as corrections
for any crystal deterioration during the data collection
(SADABS, V. 2.05, Bruker-AXS, Madison, WI, 2000). The
structures were solved by direct methods (SHELX-97) and
refined by full-matrix least-squares based on F2 using the
SHELXTL-PLUS program package (SHELXTL-PLUS, V. 6.10, Bru-
ker-AXS, Madison, WI, 2000). Hydrogen atoms were
placed in calculated positions provided by a difference
map. All were included as riding contributions (C–H =
3.17. Preparation of cis-[PtCl2{(Ph2PNC4H8O)-jP}2]
(17)
To a solution of [Pt(COD)Cl2] (0.03 g, 0.08 mmol) in
CH2Cl2 (4 mL) was added a solution of 1 (0.04 g,
0.16 mmol) also in CH2Cl2 (5 mL) and the reaction mixture
was stirred at room temperature for 48 h. The solution was
concentrated to 2 mL and 1 mL of petroleum ether was
added. Cooling this solution to 0 ꢁC gave 10 as white crys-
talline material. Yield: 92% (0.06 g); m.p. 216–218 ꢁC.
Anal. Calc. for C32H36Cl2N2O2P2Pt Æ 0.5CH2Cl2: C, 45.86;
1
H, 4.38; N, 3.29. Found: C, 45.71; H, 4.30; N, 3.46%. H
NMR (300 MHz, CDCl3): d 7.89–6.91 (m, 10H, Ph), d
˚
3.53 (t, 4H, OC2H4), d 3.22 (t, 4H, NC2H4). 31P{1H}
0.95–0.98 A) with isotropic displacement parameters
1
1.2–1.5 times those of the attached carbon atoms. Two ori-
entations were deduced from difference maps and were
constrained to be regular hexagons in the final refinement.
Other details of the data collections and refinements spe-
cific to these compounds are summarized in Table 1.
NMR (300 MHz, CDCl3): d 50.7 (s), JPPt = 3968 Hz.
MS (FAB): 772 (M ꢀ Cl).
3.18. Preparation of cis-[PtCl2{(Ph2PNC4H8NMe)-jP}2]
(18)
As for 17, using [Pt(COD)Cl2] (0.02 g, 53 lmol) and 2
(0.03 g, 106 lmol). Yield: 95% (43 mg); m.p. 164–166 ꢁC
(dec). Anal. Calc. for C34H42Cl2N4P2Pt: C, 48.93; H,
5.07; N, 6.71. Found: C, 48.26; H, 5.09; N, 6.17%. 1H
NMR (400 MHz, CDCl3): d 3.2 (s, 4H, CH2), 2.4 (s, 4H,
Acknowledgements
We thank the Department of Science and Technology
(DST), New Delhi, for financial support of the work done
at the Indian Institution of Technology, Bombay. J.T.M.
acknowledges the support of the Louisiana Board of Re-
gents through the Louisiana Educational Quality Support
Fund (Grant: LEQSF (2002-2003)-ENH-TR-67) for pur-
chase of the Bruker APEX diffractometer and Tulane Uni-
versity, New Orleans, LA, USA for the support of the
Crystallography Laboratory. We thank the regional
Sophisticated Center (RSIC), IIT Bombay for recording
NMR spectra.
CH2), 2.2 (s, 3H, CH2), 7.43–7.16 (m, 10H, phenyl).
1
31P{1H} NMR (400 MHz, CDCl3): d 50.2 (s), JPPt
=
3965 Hz.
3.19. Preparation of [AuCl{(PPh2NC4H8NMe)-jP}] (19)
A solution of [ClAu(SMe2)] (0.026 g, 88.8 lmol) in
dichloromethane (10 mL) was added dropwise to a solution

M.S. Balakrishna et al. / Polyhedron 25 (2006) 3215–3221
3221
(b) A. Caballero, F.A. Jalo’n, B.R. Manzano, G. Espino, M. Pe’rez-
Manrique, A. Mucientes, F.J. Poblete, M. Maestro, Organometallics
23 (2004) 5694.
Appendix A. Supplementary material
Full details of data collection and structure refinement
for compounds 8 and 14 have been deposited with the
Cambridge Crystallography Data Centre, CCDC Nos.
606036 and 265737. Copies of this information may be
obtained free of charge from the Director, CCDC, 12
Union Road, Cambridge CB2 1EZ, UK (fax: +44 1223
336033; e-mail: deposit@ccdc.cam.ac.uk or www://
http.ccdc.cam.ac.uk). Supplementary data associated with
this article can be found, in the online version, at
doi:10.1016/j.poly.2006.05.041.
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