Transition metal complexes of N1,N1,N2,N2-tetrakis(diphenylphosphaneyl)-ethane-1,2-diamine [(Ph2P)2NCH2CH2N(PPh2)2]

Article abstract of DOI:10.1016/j.poly.2019.03.029

The reaction of ethylenediamine with four equivalents of chlorodiphenylphosphine in the presence of a base produced tetraphosphine [(Ph₂P)₂NCH₂CH₂N(PPh₂)₂] (1) which on further treatment wi

Full text of DOI:10.1016/j.poly.2019.03.029

Accepted Manuscript
Transition metal complexes of N1,N1,N2,N2 -tetrakis(diphenylphosphaneyl)-
ethane-1,2-diamine [(Ph2P)2NCH2CH2N(PPh2)2]
Vitthalrao S. Kashid, Basvaraj S. Kote, Harish S. Kunchur, Joel T. Mague,
Maravanji S. Balakrishna
PII:
S0277-5387(19)30202-5
https://doi.org/10.1016/j.poly.2019.03.029
POLY 13830
DOI:
Reference:
Polyhedron
To appear in:
Received Date:
Revised Date:
Accepted Date:
27 January 2019
18 March 2019
19 March 2019
Please cite this article as: V.S. Kashid, B.S. Kote, H.S. Kunchur, J.T. Mague, M.S. Balakrishna, Transition metal
complexes of N1,N1,N2,N2 -tetrakis(diphenylphosphaneyl)- ethane-1,2-diamine [(Ph2P)2NCH2CH2N(PPh2)2],
Polyhedron (2019), doi: https://doi.org/10.1016/j.poly.2019.03.029
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Transition metal complexes of N1,N1,N2,N2-tetrakis(diphenylphosphaneyl)-
ethane-1,2-diamine [(Ph2P)2NCH2CH2N(PPh2)2]†ɸ
Vitthalrao S. Kashida, Basvaraj S. Kotea, Harish S. Kunchura, Joel T. Magueb and Maravanji
S. Balakrishnaa,*
aPhosphorus Laboratory, Department of Chemistry, Indian Institute of Technology Bombay,
Mumbai-400076, India
bDepartment of Chemistry, Tulane University, New Orleans, Louisiana 70118, USA.
*Corresponding author. Fax: +91 22 5172 3480, +91 22 2576 7152.
E-mail addresses: krishna@chem.iitb.ac.in and msb_krishna@iitb.ac.in
†Electronic supplementary information (ESI) available: Characterization data for all new
compounds, single crystal X-ray structure analyses of complexes 1–6 and 8. CCDC 1893775–
1893781. For ESI and crystallographic data in CIF or other electronic format see
https://www.journals.elsevier.com/polyhedron
ɸ Dedicated to Prof. Akhil R. Chakravarty on the occasion of his 65th birthday
ABSTRACT:
The reaction of ethylenediamine with four equivalents of chlorodiphenylphosphine in the
presence of a base produced tetraphosphine [(Ph2P)2NCH2CH2N(PPh2)2] (1) which on further
treatment
[(Ph2P(O))2NCH2CH2N((O)PPh2)2] (2). Treatment of 1 with two equivalents of Mo0, W0, NiII
and precursors yielded [{Mo(CO)4}2(Ph2P)2NCH2CH2N(PPh2)2] (3),
RuII
with
H2O2
(30%
aq.)
gave
tetrakis(phosphineoxide)
[{W(CO)4}2(Ph2P)2NCH2CH2N(PPh2)2] (4) [{NiCl2}2(Ph2P)2NCH2CH2N(PPh2)2] (5) and
[{Ru(η5-C5H5)PPh3}2(Ph2P)2NCH2CH2N(PPh2)2][Cl]2 (6). The reactions of 1 with
[Cu(NCCH3)4][BF4] and [AuCl(SMe2)] resulted in the formation of di- and tetranuclear
complexes
[{Cu(NCCH3)2}2(Ph2P)2NCH2CH2N(PPh2)2][BF4]2
(7)
and
[{Au2Cl2}2(Ph2P)2NCH2CH2N(PPh2)2] (8), respectively. All the compounds were
characterized by various spectroscopic methods and compounds 1–6 and 8 were characterized
by single crystal X-ray diffraction analysis.
Key Words: Aminophosphine; Chelation; Tetraphosphine; Transition metal complex; X-ray
structure
1

Introduction
Diphosphinoamines or diphosphazanes, of the type RN(PX2)2, are prominent among
bisphosphine ligands in coordination chemistry.[1, 2] These ligands due to the short bite,
exhibit both chelating and bridged bidentate coordination modes, which are greatly influenced
by the steric and electronic properties of phosphorus substituents and the nature of the metal
atoms.[3-5] Although, P–N bonds are sensitive to acid or base catalysed hydrolysis,[6] it can
be prevented or minimized by using appropriate substituents on both phosphorus and nitrogen
atoms.[7] Several tetradentate ligands of the type [P(CH2CH2PPh2)3],[8]
[(Ph2PCH2)2NCH2CH2N(CH2PPh2)2],[9]
[1,4-C6H4N{(PCl2)2}2][10]
and
[(Ph2PCH2)PPhCH2PPh(CH2PPh2)][11] are known and their transition metal chemistry has
been extensively studied. Transition metal complexes of aminophosphines ligands find
catalytic utility in various organic transformations, including allylic alkylation,[12-14]
amination,[15-19] Heck,[20, 21] Suzuki,[22, 23] hydroformylation[24, 25] and hydrogenation
reactions.[26-28]
We have studied extensively the transition metal chemistry of aminophosphine[29, 30] and
aminobis(phosphine) ligands and their catalytic and photophysical properties.[30-37] This
paper describes the reactions of N1,N1,N2,N2-tetrakis(diphenylphosphaneyl)ethane-1,2-diamine
with group 6 carbonyl derivatives, ruthenium(II), nickel(II), copper(I) and gold(I) complexes.
Results and discussion
Compounds 1 and 2 have been synthesized by previously reported method with little
modification.[38] The reaction between ethylenediamine and chlorodiphenylphosphine in a 1:4
ratio
afforded
N1,N1,N2,N2-tetrakis(diphenylphosphaneyl)ethane-1,2-diamine
[(Ph2P)2NCH2CH2N(PPh2)2] (1) as a white solid (Scheme 1). The 31P{1H} NMR spectrum of
2

1 showed a single resonance at 61.2 ppm. The mass spectrum of 1 showed m/z ion peak for
[M+Na]+ at 819.07. The IR spectrum showed νP-N-P at 886 cm-1.
O
PPh2
N
PPh2
N
H2O2, THF, 4 h
PPh2Cl, NEt3,
toluene
Ph2
P
Ph2P
O
NH2
O
PPh2
N
P
N
H2N
Ph2
Reflux, 12 h
Ph2P
PPh2
O
Ethylenediamine
1
2
Scheme 1. Synthesis of 1 and its oxidation reaction.
The reactions of 1 with an excess of H2O2 (30 % aqueous) in tetrahydrofuran at room
temperature produced tetrakis(oxide) [(Ph2P(O))2NCH2CH2N((O)PPh2)2] (2) (Scheme 1). The
31P{1H} NMR spectrum of 2 showed a single resonance at 32.3 ppm. The mass spectrum of 2
showed m/z molecular ion peak [M+H]+ at 861.23.
The perspective views of the molecular structures of 1 and 2 along with the atom labelling
scheme are shown in Figs. 1 and 2. The crystallographic data and the details of structure
determination are given in Table 1 and the selected bond distances [Å] and the bond angles [°]
are listed in the respective Fig. captions.
The PNP bond angle of 123.0(3)°and the PN bond distances 1.718(4) and 1.720(5) Å in
1 is in the expected range with partial N2Pπ→P* multiple bonding. The PN bond distance in
1 is slightly shorter than that observed in terpy-C6H4N(PPh2)2 (P−N = 1.721(2) and 1.731(2)
Å). The sum of the angles around nitrogen atom is 360° indicating the planar geometry around
the nitrogen atom.[7] Both the phenyl groups on phosphorus are in trans disposition with
respect to the P-N-P skeleton.
As evident from the molecular structure of 2, the oxygen atoms of each P−N−P arm are
projected opposite to each other with P-N-P angle of 125.08(12)° which is slightly larger than
that found in tetraphosphine 1 (123.0(3)°). In the molecular structure of 2 out of four oxygen
atoms two form hydrogen bonding (O···H25A distance of 2.369 Å and O…H25A−C bond
3

angle of 123.69°) with the methylene groups of ligand backbone, as a result they are oriented
in opposite direction. The hydrogen bonding in 2 is supported by its 1H NMR spectrum where
the methylene protons of 2 appeared downfield (3.67 ppm) compared to 1 (3.18 ppm) due to
its hydrogen bonding with oxygen atoms.
Fig. 1. Molecular structure of [(Ph2P)2NCH2CH2N(PPh2)2] (1). All hydrogen atoms have been
omitted for clarity. Thermal ellipsoids are drawn at the 50% probability level. Selected bond
distances (Å) and bond angles (°) for 1: C25N1 = 1.478(7), P1N1 = 1.718(4), P2N1 =
1.720(5); P1N1P2 = 123.0(3), C25N1P1 = 121.3(4), C25N1P1 = 115.7(2).
4

Fig. 2. Molecular structure of [(Ph2P(O))2NCH2CH2N((O)PPh2)2] (2). All hydrogen atoms
have been omitted for clarity. Thermal ellipsoids are drawn at the 50% probability level.
Selected bond distances (Å) and bond angles (°) for compound 2: P1O1 = 1.4899(19), P1N1
= 1.698(2), N1C25 = 1.504(3), P2N1 = 1.719(2), P2O2 = 1.493(2), P1C7 = 1.814(3),
N1C25 = 1.504(3), C25C25’ = 1.537(4); O1P1N1 = 110.28(11), P1N1P2 =
125.08(12), O2P2N1 = 109.87(11), O2P2C19 = 111.27(11), N1P2C13 = 108.35(10),
N1P2C19 = 107.03(11), O1P1C7 = 112.01(12), O1P1C1 = 112.09(12).
Transition metal complexes of 1 with Mo0, W0, NiII and RuII
The reactions of 1 with two equivalents of [M(C5H11N)2(CO)4] (M = Mo, W) in
dichloromethane
at
room
temperature
afforded
binuclear
complexes
[{M(CO)4}2(Ph2P)2NCH2CH2N(PPh2)2] (M = Mo 3, M = W 4), respectively (Scheme 2). The
31P{1H} NMR spectra of 3 and 4 showed single resonances at 91.8 and 68 ppm, respectively.
The complex 4 showed characteristic 183W satellites with a 1JWP coupling of 215 Hz, which is
comparable to the same found in analogues complexes.[34, 39]
The mass spectra of complexes 3 and 4 showed m/z ion peaks for [M+Na]+ at 1238.98 and
1411.074, respectively. The IR spectra of 3 and 4 showed νC≡O at 2018 and 2014 cm-1 for axial
carbonyls and, 1898 and 1877 cm-1, for equatorial carbonyls, whereas νP-N-P was observed at
872 and 874 cm-1, respectively.
The reaction of 1 with two equivalents of [Ni(DME)Cl2] in dichloromethane afforded
31
[{NiCl2}2(Ph2P)2NCH2CH2N(PPh2)2] (5). The P{1H} NMR spectrum of 5 showed a single
resonance at 31.8 ppm. The mass spectrum of complex 6 showed the m/z ion peak for [M+H]+
1
at 1181.9480. H and 13C{1H} NMR and elemental analysis data support the proposed
structure.
5

OC
CO
2[Ni(DME)Cl2]
Cl
PPh2
N
PPh2
N
M
2[M(C5H11N)2(CO)4]
CH2Cl2
OC
Ph2
P
PPh2
CH2Cl2
PPh2
N
Ni
Cl
Ph2
P
Ph2P
N
OC
CO
CO
P
N
PPh2
Ph2
P
N
M
rt, 6 h
1
Cl
Ph2P
rt, 5 h
Ph2
Ni
OC
Ph2P
CO
[Ru(5-C5H5)(PPh3)2Cl]
Cl
3
4
M = Mo
M = W
5
CH2Cl2, rt, 5 h
Ph3P
Ru
PPh2
Ph2
P
N
2Cl
P
N
Ph2
Ru
Ph2P
PPh3
6
Scheme 2. Synthesis of Mo0, W0, NiII and RuII complexes of 1.
The compound 1 was reacted with two equivalents of [Ru(η5-C5H5)(PPh3)2Cl] in
dichloromethane at room temperature to yield a dicationic complex [{Ru(η5-C5H5)PPh3}2
31
(Ph2P)2NCH2CH2N(PPh2)2][Cl]2 (6). The P{1H} NMR spectrum of 6 showed a doublet at
84.7 ppm for PPh2 moiety and a triplet at 43.6 ppm for PPh3with a 2JPP coupling of 34 Hz (Fig.
3).
The solid state structures of 3–6 are presented in Figs. 4–6. The crystallographic data and
the details of structure determinations are given in Table 1 with selected bond distances [Å]
and bond angles [°] are listed in Fig. captions.
In both the complexes the PNP arm of 1 coordinates through two phosphorus atoms to
the metal in cis-conformation and show distorted octahedral geometry around metal centres as
depicted in Fig. 4. The bond angles P2Mo1P1 and P2W1P1 are 64.90(3)° and 64.92(8)°,
respectively, which are deviated from ideal square planar geometry (90°). The PNP angles
in 3 and 4 are 102.45(11)° and 103.0(4)°, respectively. The average PN bond distances in both
the complexes are 1.716(2) Å and 1.711(7) Å. The O2C27 and O1C28 bond lengths are
1.148(3) and 1.162(13) Å.
6

84.8
43.6 43.2
100
95
90
85
80
75
70
65
ppm
60
55
50
45
40
35
30
Fig. 3. 31P{1H} NMR spectrum of 6 recorded in CDCl3.
The molecular structure of complex 5 was also confirmed by single crystal X-ray analysis.
The PNP angle of 5 is smaller than that of compound 1 and other metal complexes (96.9(2)°)
(Fig. 5). The nickel(II) ion adopts square planar geometry and the sum of the angles around
nitrogen atom in 6 is 360(2)°. The Cl1Ni1Cl2 bond angle is 97.83(8)° which is slightly
deviated (8°) from the ideal square planar geometry (90°). The average bond distances of
Ni1Cl1, PN and PNi are 2.1964 (10) Å, 1.692(6) Å and 2.1270(9) Å, respectively. The
P‒N bond distances of 1.695(4) and 1.690(6) Å in 6 are slightly shorter than the same in 1.
7

3
4
Fig. 4 Molecular structures of [Mo(CO)4(Ph2P)2NCH2CH2N(PPh2)2Mo(CO)4] (3) and
[W(CO)4(Ph2P)2NCH2CH2N(PPh2)2W(CO)4] (4). All hydrogen atoms have been omitted for
clarity. Thermal ellipsoids are drawn at the 50% probability level. Selected bond distances [Å]
and bond angles [°] for compound 3: Mo1C27 = 1.995(3), Mo1C28 = 2.040(3), P1N1 =
1.723(2), P2N1 = 1.709(2), Mo1P2 = 2.4647(8), Mo1P1 = 2.5205(8), O2C27 = 1.148(3),
O3C28 = 1.141(3); P2Mo1P1 = 64.90(3), P2N1P1 = 102.45(11), C27Mo1P2 =
166.29(8), C29Mo1P1 = 159.78(8), C27Mo1P1 = 104.17(8), C29Mo1P2 = 96.92(8),
N1P1Mo1 = 93.76(7). For compound 4: W1P1 = 2.508(2), W1P2 = 2.483(3), W1C26
= 2.032(11), O2C26 = 1.162(13), P2N1 = 1.721(7), P1N1 = 1.701(8); P3N2 = 1.714(4),
P4N2 = 1.709(4), P2W1P1 = 64.92(8), P1N1P2 = 103.0(4), C26W1P2 = 89.1(3),
C26W1P1 = 93.0(3), C29W1P1 = 159.7(3), C29W1P2 = 94.9(3), P4W2P3 =
65.31(8).
8

Fig. 5. Molecular structure of complex [NiCl2(Ph2P)2NCH2CH2N(PPh2)2NiCl2] (5). All
hydrogen atoms have been omitted for clarity. Thermal ellipsoids are drawn at the 30%
probability level. Selected bond distances (Å) and bond angles (°) for compound 5: Ni1Cl1 =
2.1949(19), Ni1Cl2 = 2.198(2), Ni1P1 = 2.1301(17), Ni1P2 = 2.124(2), P1P2 = 2.533(3),
P1N1 = 1.692(6); Cl1Ni1Cl2 = 97.83(8), P1Ni1Cl1 = 165.38(9), P1N1P2 = 96.9(2),
N1P1Ni1 = 94.42(17), P2Ni1Cl2 = 168.19(7), C25N1P2 = 129.9(4).
Fig. 6 Molecular structure of complex [Ru(η5-C5H5)PPh3{-{(Ph2P)2NCH2CH2N(PPh2)2}-
κ2(P,P),-κ2(P,P)}Ru(η5-C5H5)PPh3][Cl]2 (6). All hydrogen atoms have been omitted for clarity.
Thermal ellipsoids are drawn at the 50% probability level. Selected bond distances (Å) and
bond angles (°) for compound 6: Ru1P1 = 2.2988(13), Ru1P2 = 2.3019(12), Ru1P3 =
2.3537(13), P1N1 = 1.706(4), P2N1 = 1.702(4), N1C25 = 1.485(6); P1Ru1P2 =
68.95(4), P1Ru1P3 = 100.39(4), N1P1Ru1 = 95.49(14), N1P2Ru1 = 95.52(14),
C25N1P1 = 130.2(3), P2N1P1 = 99.7(2).
9

The molecular structure of 6 was also confirmed by the single crystal X-ray analysis. The
ruthenium(II) atoms adopt distorted octahedral geometry in 6 (Fig. 6). The PNP bond angle
in complex 6 is smaller (99.7(2)°) than the same in free ligand (123.0(3)°) due to the strained
four-membered chelate ring formation. The PN bond distances of 1.706(4) and 1.702(4) Å,
in the expected range and comparable to the same in analogues complexes.[29] The PRuP
bite angle is 100.39(4)°. The RuP (PPh2) and RuP (PPh3) bond distances are 2.3003(12) and
2.3537(13) Å, respectively (Table 2.3.4).
Group 11 metal complexes of [(Ph2P)2NCH2CH2N(PPh2)2] (1)
The reaction of 1 with two equivalents of [Cu(NCCH3)4][BF4] in acetonitrile at room
temperature yielded [{Cu(NCCH3)2}2(Ph2P)2NCH2CH2N(PPh2)2][BF4]2 (7) as white solid
(Scheme 3). The 31P{1H} NMR spectrum of 8 showed a broad singlet at 60.2 ppm. The mass
spectra of complexes 7 and 8 showed m/z ion peaks for [M-2BF4] and [M-2Cl] at 959.08 and
1655.41, respectively. Similarly, the reaction of 1 with four equivalents of [AuCl(SMe2)] in
dichloromethane at room temperature afforded a tetranuclear complex [Au2Cl2(Ph2P)2NCH2-
CH2N(PPh2)2Au2Cl2] (8) (Scheme 3). The 31P{1H} NMR spectrum of 8 showed a single
resonance at 81.4 ppm.
PPh2
Ph2P
N
N
PPh2
1
PPh2
2[Cu(NCCH3)4][BF4]
4[AuCl(SMe2)]
CH2Cl2, rt, 4 h
CH3CN, rt, 6 h
Ph2
P
Ph2
P
Ph2P
AuCl
AuCl
NCCH3
ClAu
PPh2
CH3CN
CH3CN
N
Cu
N
Cu
N
N
2BF4
NCCH3
P
Ph2P
Ph2
ClAu
PPh2
P
Ph2
7
8
Scheme 3. Synthesis of copper(I) and gold(I) complexes of 1.
10

The crystallographic data and the details of structure determination are given in Table 1 and
the selected bond distances [Å] and the bond angles [°] are listed in Fig. 7. A view of the
molecular structure of 8 along with the atom labeling scheme is shown in Fig. 7.
Fig. 7 Molecular structure of complex [Au2Cl2(Ph2P)2NCH2CH2N(PPh2)2Au2Cl2] (8). All
hydrogen atoms have been omitted for clarity. Thermal ellipsoids are drawn at the 50%
probability level. Selected bond distances [Å] and bond angles [°] angles for 9: Au1P1 =
2.241(5), Au1Cl1 = 2.291(5), Au1Au2 = 3.0198(13), P1N1 = 1.728(17), P2N1 =
1.712(16), N1C25 = 1.77(5); P1Au1Cl1 = 177.70(18), P2N1P1 = 113.5(8), P2N1C25
= 122.1(13), P1Au1Au2 = 80.28(13), P2Au2Cl2 = 172.21(19).
The structure consists of four gold atoms coordinated to four phosphorus atoms with gold
atoms showing linear geometry. The P1Au1Cl1 bond angle is 177.70(18)°. The Au—Au
bond distance of 3.0198(13) Å (Fig. 7), which is similar to the same found in [4′-
{p‐(Ph2PAuCl)2NC6H4}-2,2′6′2′′-terpy] (2.996(9)) Å [37] and shorter than the same in
[ClAu(PPh2N(H)Ph2P)AuCl] 3.121(1) Å, [40] and strong aurophilic interactions.[41, 42] Both
P—Au—Cl moieties are almost parallel with a Au1P1 distance of 2.241(5) Å. The PNP
bond angle is 113.5(8)°.
Conclusions
11

In summary, the reactions of 1 with metal precursors such as Mo0, W0, NiII and RuII
resulted
in
bimetallic
complexes
and
[{Mo(CO)4}2(Ph2P)2NCH2CH2N(PPh2)2],
[{NiCl2}2(Ph2P)2NCH2CH2N(PPh2)2],
[{W(CO)4}2(Ph2P)2NCH2CH2N(PPh2)2]
respectively. Dicationic complex [{Ru(η5-C5H5)PPh3}2(Ph2P)2NCH2CH2N(PPh2)2][Cl]2 was
isolated in the reaction of 1 with [Ru(η5-C5H5)(PPh3)2Cl]. The treatment of 1 with
[Cu(NCCH3)4][BF4] resulted in dicopper(I) complex, whereas [AuCl(SMe2)] afforded a
tetragold complex [Au2Cl2(Ph2P)2NCH2CH2N(PPh2)2Au2Cl2] (8). It would be interesting to
selectively oxidize phosphorus atoms to make it multifunctional or to add hemilabile
functionality as these class of ligands will be very valuable in homogeneous catalysis. The
work in this direction is in progress in our laboratory.
Experimental
General procedures
All manipulations were performed using standard vacuum-line and Schlenk techniques
under nitrogen atmosphere unless otherwise stated. All the solvents were purified by
conventional methods[43] and distilled prior to use. The compounds, N1,N1,N2,N2-
tetrakis(diphenylphosphaneyl)ethane-1,2-diamine [(Ph2P)2NCH2CH2N(PPh2)2] (1)[38] and
[Ru(η5-C5H5)(PPh3)2Cl],[44] [M(CO)4(C5H11N)2] (M = Mo, W),[45] [Ni(DME)Cl2],[46]
[Cu(MeCN)4BF4][47] and [AuCl(SMe2)][48] were prepared according to the published
procedures. All other chemicals were obtained from commercial sources and purified prior to
use.
Instrumentation
The NMR spectra were recorded at the following frequencies: 400 or 500 MHz (1H), 162
or 202 MHz (31P) and 100 or 125 MHz (13C) using Bruker Avance-400 or Bruker Avance-500
13
MHz spectrometer. The C{1H} and 31P{1H} NMR spectra were acquired using broad band
proton decoupling. The spectra were recorded in CDCl3 solutions with CDCl3 as an internal
12

1
13
lock; chemical shifts of H and C{1H} NMR spectra are reported in ppm downfield from
31
TMS, used as internal standard. The chemical shifts of P{1H} NMR spectra are referred to
85% H3PO4 (in D2O) used as external standard. The microanalyses were performed using a
Carlo Erba Model 1112 elemental analyzer. Mass spectra were recorded on BRUKER mass
spectrometer using Electro-spray ionization mass spectrometry (ESI-MS) method. The melting
points were observed in capillary tubes and are uncorrected.
X-Ray Crystallography
A crystal of all the compounds 1 – 6 and 8 are suitable for single crystal X-ray analyses was
mounted on a Cryoloop with a drop of Paratone oil and placed in the cold nitrogen stream of
the Kryoflex attachment of the Bruker APEX CCD diffractometer (compound 6) or Rigaku
Saturn 724+ (4×4 bin mode) (Compounds 1-5 and 8) CCD diffractometer. For compounds 1-
5 and 8 the data were collected and reduced using CrystalClear-SM Expert 2.0 r7 (Rigaku,
2011) software. The structures were solved using Olex2[49] with the ShelXT[50] structure
solution program using intrinsic phasing and refined with the ShelXL[51] refinement package
using least squares minimization, whereas for compound 6, full sphere of data was collected
using different sets of frames using the APEX2[52] program suite. For all the compounds, the
raw data were reduced to F2 values using the SAINT software.[52] Multiple measurements of
equivalent reflections provided the basis for an empirical absorption correction as well as a
correction for any crystal deterioration during the data collection (SADABS[52]). The structure
was solved by direct method (SHELXS[53]) and refined by full-matrix least-squares procedures
on F2 using SHELXL[53] (SHELXTL program package[53]). Hydrogen atoms attached to
carbon were placed in calculated positions and included as riding contributions with isotropic
displacement parameters tied to those of the attached non-hydrogen atoms. The compounds 1-
3, 5 and 6 have center of symmetry lying at the centre of the methylene units (-CH2‒CH2-).
13

The asymmetric units of compounds 3 and 8 contain two dichloromethane molecules as solvent
of crystallization, whereas compound 5 contains one molecule of dimethylformamide and 6
contains one molecule of dichloromethane together with two molecules of water. In compounds
5 and 8 some of the atoms are affected by thermal vibrational disorder giving a prolate ellipsoid.
In compound 8 the methylene units are disordered over two positions in 60:40 ratio and the
large solvent assessable void could not be identified or modeled to a known solvent, hence it
was SQUEEZED using PLATON.[54] The results indicated 227 electrons, and volume of 461
Å3. The reflections with error/esd >10 were excluded in order to avoid problems related to
better refinement of the data. The data completeness is more than 98% in most of the cases,
which is enough to guarantee a very good refinement of data. Crystallographic data (including
structures factors) for the structures reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary publication no. CCDC No.
1893777 (Compound 1), 1893775 (Compound 2), 1893776 (Compound 3), 1893779
(Compound 4), 1893778 (Compound 5), 1893781 (Compound 6), 1893780 and (Compound
8).
14

Table 1 Crystallographic data of 1-6 and 8
1
2
3
4
5
6
8
formula
C50H44N2P4
C50H44N2O4P4 C58H44N2O8P4 C58H44N2O8P4
C50H44Cl4N2Ni2 C96H84Cl4N2P6Ru· C50H44Au4Cl4N2P4
Mo2·2CH2Cl2
1382.56
monoclinic
W2
P4·2C3H7NO
1202.16
monoclinic
2CH2Cl2·2H2O
2001.29
monoclinic
·2CH2Cl2
1896.27
monoclinic
Formula weight 796.75
860.75
monoclinic
1388.53
orthorhombic
Crystal system
Monoclinic
Space group
a/Å
b/Å
c/Å
α/°
P21/n
I2/a
P21/c
Pna21
P21/c
P21/n
P21/n
10.444(7)
9.351(6)
21.342(12)
90.00
21.059(18)
9.575(6)
22.787(14)
90
11.829(2)
17.129(3)
14.633(3)
90
23.837(4)
9.6045(10)
23.530(4)
90
12.914(3)
10.690(5)
19.880(3)
90
13.173(11)
19.687(17)
18.046(16)
90
15.564(6)
17.463(6)
22.955(8)
90
β/°
γ/°
Volume/Å3
Z
91.794(5)
90.00
2083.6(2)
2
106.93(6)
90
4396(6)
4
92.770(2)
90
2961.71(9)
2
90
90
96.906(2)
90
2724.80(15)
2
90.2350(10)
90
4680.2(7)
2
107.482(4)
90
5951(4)
4
5387.38(14)
4
ρcalcg/cm3
μ/mm-1
F(000)
Crystal
size/mm3
T/K
1.270
0.219
836.0
1.301
0.219
1800.0
1.550
0.768
1396.0
1.712
4.443
2712.0
0.85 × 0.158 ×
0.145
1.465
4.138
1244.0
1.420
0.703
2048.0
2.117
10.333
3544.0
0.15 × 0.13 × 0.09
0.16× 0.13× 0.38 × 0.13 × 0.163 × 0.125
0.09
150
0.133 × 0.095 × 0.224 × 0.18 ×
0.075
150
0.12
150
× 0.098
150
0.069
150.15
150
100.0
2θ range/°
Total no. of
reflns
4.29 to 50
28707
6.25 to 57.79 4.75 to 62.32
3.86 to 62.34
59998
6.89 to 145.29
16951
3.72 to 58.25
86054
6.05 to 49.99
58497
21366
32513
Independent
reflections
R1
3672
5539
8615
15932
5297
12433
10452
0.0666
0.1939
1.081
0.0613
0.1391
1.057
0.0360
0.0895
1.039
0.0289
0.0579
1.029
0.0602
0.1815
1.040
0.0692
0.2232
1.038
0.0871
0.1602
1.234
wR2
S
Where w = 1/[\s2(Fo2) + (0.0241P)2 + 1.2733P], where P = (Fo2 + 2F2)/3
15

Preparation of [(Ph2P)2NCH2CH2N(PPh2)2] (1). To a well stirred solution of
ethylenediamine (2 g, 3.72 mmol) and triethylamine (14.13 g, 7.45 mmol) in toluene (50 mL),
a solution of chlorodiphenylphosphine (1.02 g, 3.72 mmol) in the same solvent (15 mL) was
added dropwise at 0 °C. The reaction mixture was allowed to warm to room temperature and
refluxed for 12 h. The reaction mixture was filtered through Celite, and then the solvent was
evaporated under reduced pressure to obtain 1 as an off white solid. The compound 1 was
crystallized by the slow diffusion of petroleum ether into a saturated solution of 1 in
dichloromethane. The spectroscopic data of 1 were consistent with reported values.
Synthesis of [(Ph2P(O))2NCH2CH2N((O)PPh2)2] (2). A 30% aqueous solution of H2O2 (0.010
g, 0.424 mmol) in THF (10 mL) was added dropwise to a well-stirred solution of 1 (0.05 g,
0.062 mmol) in the same solvent (10 mL). The reaction mixture was stirred for 4 h at room
temperature. The solvent was removed under reduced pressure to obtain 2 as white solid. The
2 was recrystallized from dichloromethane and petroleum ether. Yield 76% (0.04 g). HRMS
(ESI): m/z Calcd. for C50H45N2P4O4 [M+H]+, 861.2324 found: 861.2327. 1H NMR (500 MHz,
CDCl3): δ 7.55-7.23 (m, 40H, ArH), 3.66 (s, 4H, CH2). 31P{1H} NMR (161.97 MHz, CDCl3):
δ 32.0 (s).
Synthesis of [Mo(CO)4(Ph2P)2NCH2CH2N(PPh2)2Mo(CO)4] (3). A dichloromethane
solution (10 mL) of 1 (0.015 g, 0.018 mmol) was added dropwise to a solution of
[Mo(C5H11N)2(CO)4] (0.014 g, 0.037 mmol) in the same solvent (10 mL). The reaction mixture
was further stirred for 5 h at room temperature. The volatiles were removed under reduced
pressure to afford 3 as a yellow solid and it was recrystallized from dichloromethane and
petroleum ether. Yield: 70 % (0.015 g). Mp: 230-232 °C (dec.). Anal. Calcd. for
C58H44Mo2N2O8P4: C, 57.44; H, 3.66; N, 2.31. Found: C, 57.28; H, 3.68; N, 2.45. MS (ESI):
m/z Calc for C58H44N2O8P4Mo2 (M+Na):1239.0053, Found: 1238.9847. FT IR (KBr disc) cm-
16

1: υC≡O: 2018 vs, 1898vs. 1H NMR (400 MHz, CDCl3): δ 7.44-7.07 (m, 40H, ArH), 3.1 (s, 4H,
CH2). 31P{1H} NMR (161.97 MHz, CDCl3): δ 91.8 (s).
Synthesis of [W(CO)4(Ph2P)2NCH2CH2N(PPh2)2W(CO)4] (4). This was synthesized by
procedure similar to that of 3, using 1 (0.015 g, 0.018 mmol) and [W(C5H11N)2(CO)4] (0.0175
g, 0.037 mmol). Yield 87%. Mp: 225-229 °C (dec.). Anal. Calcd. for C58H44W2N2O8P4: C,
50.17; H, 3.19; N, 2.02. Found: C, 50.32; H, 3.08; N, 2.23. MS (ESI): m/z Calc for
C58H44N2O8P4W2 [M+Na]+: 1411.0964, Found: 1411.0784. FT-IR (K.Br disc) cm-1: υC≡O: 2014
vs, 1877 vs.1H NMR (500 MHz, CDCl3): δ 7.45-7.06 (m, 40H, ArH), 3.12 (s, 4H, CH2).
31P{1H} NMR (202.45 MHz, CDCl3): δ 68.0 (s, 1JPW = 215.4 Hz).
Synthesis of [NiCl2(Ph2P)2NCH2CH2N(PPh2)2NiCl2] (5). To a solution of 1 (0.025 g, 0.03
mmol) in dichloromethane (10 mL) was added dropwise a solution of [Ni(DME)Cl2] (0.0138
g, 0.062 mmol) in the same solvent (10 mL) at room temperature. The reaction mixture was
stirred for 6 h at room temperature, and then the volatiles were removed under reduced pressure
to afford a brown-red solid which was used for CHN analysis. The complex 5 was recrystallized
from a solution of dimethylformamide to obtain single crystals suitable for X-ray analysis.
Yield 78% (0.024 g). Mp: 263-267 °C (dec). Anal. Calcd. for C50H44N2P4Ni2Cl4·2CH2Cl2: C,
50.94; H, 3.95; N, 2.28. Found: C, 50.82; H, 3.59; N, 2.52. MS (ESI): m/z Calc for
C50H44N2P4Ni2Cl4 (M+H): 1054.9988, Found: 1055.2427.1H NMR (500 MHz, CDCl3): δ 7.92-
7.26 (m, 40H, ArH), 3.12 (br, s, 4H, CH2). 31P{1H} NMR (202.45 MHz, CDCl3): δ 31.8 (s).
Synthesis of [Ru(η5-C5H5)PPh3(Ph2P)2NCH2CH2N(PPh2)2Ru(η5-C5H5)PPh3][Cl]2 (6). To
a solution of 1 (0.015g, 0.018 mmol) in dichloromethane (10 mL) was added dropwise a
solution of [Ru(η5-C5H5)(PPh3)2Cl] (0.027 g, 0.037 mmol) also in dichloromethane (5 mL).
The resulting reaction mixture was stirred overnight at room temperature, filtered through
Celite, and the solvent was evaporated under reduced pressure to obtain brown solid. The 6
was further recrystallized from dichloromethane and petroleum ether. Yield 68% (0.017 g).
17

Mp: 253-257 °C (dec). Anal. Calcd. for C96H84Cl4N2P6Ru2·(2CH2Cl2,2H2O): C, 58.81; H, 4.63;
N, 1.39. Found: C, 58.73; H, 4.26; N, 1.48. 1H NMR (500 MHz, CDCl3): δ 7.48-6.85 (br, m,
70H, ArH), 3.1 (s, 4H, CH2). 31P{1H} NMR (161.97 MHz, CDCl3): δ 84.7 (d, 2JPP = 34.0 Hz,
PPh2), 43.5 (t, 2JPP = 34.0 Hz, PPh3).
Synthesis of [Cu(NCCH3)2(Ph2P)2NCH2CH2N(PPh2)2Cu(NCCH3)2][2BF4] (7). An
acetonitrile solution (10 mL) of 1 (0.015 g, 0.018 mmol) was added dropwise into a solution
of [Cu(NCCH3)4][BF4] (0.012 g, 0.036 mmol) also in acetonitrile (10 mL) at room temperature
and then reaction mixture was stirred for 6 h. The volatiles were removed under reduced
pressure to give 7 as an off-white solid. Yield 80% (0.018 g). Mp: >270 °C (dec). MS (ESI):
m/z Calc for C58H56B2Cu2F8N6P4 (M-2BF4),1088.0368 Found: 1088.0890. 1H NMR
(500 MHz, CDCl3): δ 7.70-7.12 (br, m, 40H, ArH), 2.15 (br, s 4H, CH2). 31P{1H} NMR
(161.97 MHz, CDCl3): δ 60.2 (br, s).
Synthesis of [Au2Cl2(Ph2P)2NCH2CH2N(PPh2)2Au2Cl2], 8. A dichloromethane solution (10
mL) of 1 (0.015 g, 0.018 mmol) was added dropwise to a solution of AuCl(SMe2) (0.022 g,
0.075 mmol) in the same solvent at room temperature and the reaction mixture was stirred for
4 h in dark. The volatiles were removed under reduced pressure to obtain 8 as an off-white
solid. It was recrystallized from dichloromethane and petroleum ether to obtain colourless
o
crystalline material. Yield: 84 % (0.027 g). Mp: 143-147 C (dec). Anal. Calcd. for
C50H44N2P4Au4Cl4: C, 34.78; H, 2.57; N, 1.62. Found: C, 34.45; H, 2.31; N, 1.83. MS (ESI):
m/z Calc for C50H44N2Cl4P4Au4 [M-2Cl]+: 1655.5184, Found: 1655.4124. 1H NMR (500 MHz,
31
CDCl3): δ 7.70-7.12 (br, m, 40H, ArH), 2.75 (s, 4H, CH2). P{1H} NMR (161.97 MHz,
CDCl3): δ 81.4 (s).
Appendix A. Supplementary data CCDC <18937751893781> contains the supplementary
crystallographic data for <1-6 and 8>. These data can be obtained free of charge via
http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic
18

Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail:
deposit@ccdc.cam.ac.uk.
Acknowledgements
This work was supported by a grant SB/S1/IC-108/2014 from Science & Engineering
Research Board (SERB), New Delhi, India. VSK thanks UGC, New Delhi for Senior Research
Fellowship (SRF) and IRCC for financial support. We also thank the Department of Chemistry
and Instrumentation Facilities, IIT Bombay, for spectral, analytical and some crystallographic
data. JTM thanks the Louisiana Board of Regents for the purchase of the CCD diffractometer
and the Chemistry Department of Tulane University for Support of the X-ray laboratory.
References
[1] M.S. Balakrishna, V.S. Reddy, S.S. Krishnamurthy, J.F. Nixon, J.C.T.R.B.S. Laurent,
Coord. Chem. Rev., 129 (1994) 1-90.
[2] F. Agbossou, J.-F. Carpentier, F. Hapiot, I. Suisse, A. Mortreux, Coord. Chem. Rev.,
178–180, Part 2 (1998) 1615-1645.
[3] T. Appleby, J. Derek Woollins, Coord. Chem. Rev., 235 (2002) 121-140.
[4] Z. Fei, P.J. Dyson, Coord. Chem. Rev., 249 (2005) 2056-2074.
[5] M.R.I. Zubiri, J.D. Woollins, Comment. Inorg. Chem., 24 (2003) 189-252.
[6] A.D. Burrows, M.F. Mahon, M.T. Palmer, M. Varrone, Inorg. Chem., 41 (2002) 1695-
1697.
[7] M.T. Ashby, Z. Li, Inorg. Chem., 31 (1992) 1321-1322.
[8] M.N.I. Khan, R.J. Staples, C. King, J.P. Fackler, R.E.P. Winpenny, Inorg. Chem., 32
(1993) 5800-5807.
19

[9] K. Wang, W. Wang, H. Luo, X. Zheng, H. Fu, H. Chen, R.J.C.L. Li, Catal. Lett., 143
(2013) 1214-1219.
[10] Kirsty G Gawa, Martin B Smitha, J.W. Steed, J. Organomet. Chem., 664 (2002) 294-
297.
[11] Y. Takemura, H. Takenaka, T. Nakajima, T. Tanase, Angew. Chem. Int. Ed., 48 (2009)
2157-2161.
[12] M. Bourghida, M. Widhalm, Tetrahedron: Asymmetry., 9 (1998) 1073-1083.
[13] Y. Wang, H. Guo, K. Ding, Tetrahedron: Asymmetry., 11 (2000) 4153-4162.
[14] Y. Wang, X. Li, K. Ding, Tetrahedron Lett., 43 (2002) 159-161.
[15] S. Urgaonkar, J.-H. Xu, J.G. Verkade, J. Org. Chem., 68 (2003) 8416-8423.
[16] S. Urgaonkar, M. Nagarajan, J.G. Verkade, Org. Lett., 5 (2003) 815-818.
[17] S. Urgaonkar, J.G. Verkade, Tetrahedron, 60 (2004) 11837-11842.
[18] S.L. Parisel, L.A. Adrio, A.A. Pereira, M.M. Pérez, J.M. Vila, K.K. Hii, Tetrahedron, 61
(2005) 9822-9826.
[19] S. Urgaonkar, J.G. Verkade, Adv. Synth. Catal., 346 (2004) 611-616.
[20] M.T. Reetz, G. Lohmer, R. Schwickardi, Angew. Chem. Int. Ed., 36 (1997) 1526-1529.
[21] I.P. Beletskaya, A.V. Cheprakov, Chem. Rev., 100 (2000) 3009-3066.
[22] M.L. Clarke, D.J. Cole-Hamilton, J.D. Woollins, J. Chem. Soc. Dalton Trans., (2001)
2721-2723.
[23] T. Schareina, R. Kempe, Angew. Chem. Int. Ed., 41 (2002) 1521-1523.
[24] J. Andrieu, P. Richard, J.-M. Camus, R. Poli, Inorg. Chem., 41 (2002) 3876-3885.
[25] E.J. Zijp, J.I. van der Vlugt, D.M. Tooke, A.L. Spek, D. Vogt, Dalton Trans., (2005)
512-517.
[26] R. Guo, A.J. Lough, R.H. Morris, D. Song, Organometallics, 23 (2004) 5524-5529.
[27] B. Pugin, H.-U. Blaser, Adv. Synth. Catal., 348 (2006) 1743-1751.
20

[28] C. Blanc, F. Agbossou-Niedercorn, G. Nowogrocki, Tetrahedron: Asymmetry., 15
(2004) 2159-2163.
[29] M.S. Balakrishna, D. Suresh, P.P. George, J.T. Mague, Polyhedron, 25 (2006) 3215-
3221.
[30] M.K. Pandey, J.T. Mague, M.S. Balakrishna, Inorg. Chem., 57 (2018) 7468-7480.
[31] M.S. Balakrishna, R. McDonald, Inorg. Chem. Commun., 5 (2002) 782-786.
[32] S. Priya, M.S. Balakrishna, S.M. Mobin, R. McDonald, J. Organomet. Chem., 688
(2003) 227-235.
[33] B. Punji, J.T. Mague, M.S. Balakrishna, Inorg. Chem., 45 (2006) 9454-9464.
[34] S. Naik, J.T. Mague, M.S. Balakrishna, Inorg. Chim. Acta, 407 (2013) 139-144.
[35] S. Naik, M. Kumaravel, J.T. Mague, M.S. Balakrishna, Dalton Trans., 43 (2014) 1082-
1095.
[36] S. Naik, J.T. Mague, M.S. Balakrishna, Inorg. Chem., 53 (2014) 3864-3873.
[37] S. Naik, S. Kumar, J.T. Mague, M.S. Balakrishna, Dalton Trans., 45 (2016) 18434-
18437.
[38] B. Gümgüm, O. Akba, F. Durap, L.T. Yıldırım, D. Ülkü, S. Özkar, Polyhedron, 25
(2006) 3133-3137.
[39] L. Radhakrishna, M.K. Pandey, M.S. Balakrishna, RSC Adv., 8 (2018) 25704-25718.
[40] P. Lange, A. Schier, H. Schmidbaur, in: Zeitschrift für Naturforschung B, 1997, pp.
769.
[41] H. Schmidbaur, A. Schier, Chem. Soc. Rev., 41 (2012) 370-412.
[42] H. Schmidbaur, A. Schier, Angew. Chem. Int. Ed., 54 (2015) 746-784.
[43] W.L. Armarego, D.D. Perrin, Purification of Laboratory Chemicals, 4th ed, Butterworth-
Heinemann Linacre House, Jordan Hill, Oxford, U. K., (1996).
21

[44] M.A. Bennett, T.N. Huang, T.W. Matheson, A.K. Smith, S. Ittel, W. Nickerson, Inorg.
Synth., John Wiley & Sons, Inc., (1982) 74-78.
[45] D.J. Darensbourg, R.L. Kump, Inorg. Chem. , 17 (1978) 2680-2682.
[46] A. Kermagoret, P. Braunstein, Organometallics, 27 (2008) 88-99.
[47] G.J. Kubas, Inorg. Synth., 19 (1979) 90-91.
[48] M.-C. Brandys, M.C. Jennings, R.J. Puddephatt, J. Chem. Soc., Dalton Trans., (2000)
4601-4606.
[49] O.V. Dolomanov, L.J. Bourhis, R.J. Gildea, J.A.K. Howard, H. Puschmann, J. Appl.
Cryst., 42 (2009) 339-341.
[50] G.M. Sheldrick, Acta Crystallogr., Sec. C, Str. Chem., 71 (2015) 3-8.
[51] G. Sheldrick, Acta Crystallographica Section A, 64 (2008) 112-122.
[52] Bruker-AXS, SAINT+, Version 7.03 Madison, WI, (2006).
[53] G.W. Sheldrick, SHELXL and SHELXS, Acta Cryst., A64 (2008) 112-122.
[54] A. Spek, J. Appl. Crystallography., 36 (2003) 7-13.
Transition metal complexes of N1,N1,N2,N2-tetrakis(diphenylphosphaneyl)-
ethane-1,2-diamine [(Ph2P)2NCH2CH2N(PPh2)2]†ɸ
Vitthalrao S. Kashida, Basvaraj S. Kotea, Harish S. Kunchura, Joel T. Magueb and Maravanji
S. Balakrishnaa,*
This paper describes Mo(0), W(0), Ru(II), Ni(II), Cu(I) and gold(I) complexes
of tetraphosphane, N1,N1,N2,N2-tetrakis(diphenylphosphaneyl)- ethane-1,2-
diamine.
22

Transition metal complexes of N1,N1,N2,N2-tetrakis(diphenylphosphaneyl)-
ethane-1,2-diamine [(Ph2P)2NCH2CH2N(PPh2)2]†ɸ
Vitthalrao S. Kashida, Basvaraj S. Kotea, Harish S. Kunchura, Joel T. Magueb and Maravanji
S. Balakrishnaa,*
23