Synthesis and derivatization, structures and transition metal (Mo(0), Fe(II), Pd(II) and Pt(II)) complexes of phenylaminobis(diphosphonite), PhN{P(OC6H4OMe-o)2}2

Article abstract of DOI:10.1016/j.jorganchem.2004.08.003

The synthesis, derivatization and coordination behavior of a new aminobis(diphosphonite), PhN{P(OC₆Me-o)₂} ₂ (1) is described. The ligand 1 reacts with H₂ O₂, elemental sulfur or selenium to give the corresponding dichalcogenides PhN{P(E)(OC₆Me-o)₂}₂ (E = O, 2; S, 3; Se, 4) in good yield. Reactions of 1 with Mo(CO) ₆, Pd(NCCH₃)₂Cl₂ and Pt(COD) Cl₂ resulted in the formation of the chelate complexes, Mo(CO)₄[PhN{P(OC₆Me-o)₂}₂] (5) and MCl₂[PhN{P(OC₆Me-o)₂} ₂] (M = Pd,7; M = Pt, 8) whereas in the reaction of 1 with [CpFe(CO)₂] 2 , one of the P-N bonds cleaves due to the metal assisted hydrolysis to give a mononuclear complex, [CpFe(CO){P(O) (OC₆Me-o)₂}{PhN(H)(P(OC₆ Me-o) ₂)}] (6). The molecular structures of 1, 4, 5 and 6 are determined by X-ray studies.

Full text of DOI:10.1016/j.jorganchem.2004.08.003

Journal of Organometallic Chemistry 689 (2004) 3388–3394
www.elsevier.com/locate/jorganchem
Synthesis and derivatization, structures and transition metal
(Mo(0), Fe(II), Pd(II) and Pt(II)) complexes of
phenylaminobis(diphosphonite), PhN{P(OC6H4OMe-o)2}2
a,
a
b
Maravanji S. Balakrishna *, P.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 9 July 2004; accepted 2 August 2004
Available online 9 September 2004
Abstract
The synthesis, derivatization and coordination behavior of a new aminobis(diphosphonite), PhN{P(OC6H4OMe-o)2}2 (1) is
described. The ligand 1 reacts with H2O2, elemental sulfur or selenium to give the corresponding dichalcogenides PhN{P(E)(O-
C6H4OMe-o)2}2 (E = O, 2; S, 3; Se, 4) in good yield. Reactions of 1 with Mo(CO)6, Pd(NCCH3)2Cl2 and Pt(COD)Cl2 resulted
in the formation of the chelate complexes, Mo(CO)4[PhN{P(OC6H4OMe-o)2}2] (5) and MCl2[PhN{P(OC6H4OMe-o)2}2]
(M = Pd,7; M = Pt, 8) whereas in the reaction of 1 with [CpFe(CO)2]2, one of the P–N bonds cleaves due to the metal assisted
hydrolysis to give a mononuclear complex, [CpFe(CO){P(O)(OC6H4OMe-o)2}{PhN(H)(P(OC6H4OMe-o)2)}] (6). The molecular
structures of 1, 4, 5 and 6 are determined by X-ray studies.
ꢀ 2004 Elsevier B.V. All rights reserved.
Keywords: Aminobis(diphosphonite); Dichalcogenides; Metal complexes; P–N bond cleavage; Crystal structures
1. Introduction
bonds are prone to the metal assisted cleavage to give
unusual products with or without the aid of trace
amounts of moisture or acid impurities [3,4]. Amino-
phosphines containing aryloxides are moderately stable
towards hydrolysis. Further, the aminophosphines with
pendant hemilabile groups would be more interesting as
they can provide additional weak donor sites toward
complex formation. Appropriate reagents can cleave
these metal–ligand bonds if the metal undergoes oxida-
tive addition, an important step in a variety of metal
mediated organic transformations. As a part of our
interest [5–9] and that of others [10–16] in designing ami-
nophosphines and phosphorus based ligands for transi-
tion metal chemistry and catalytic applications, herein
we report the synthesis, reactivity and Mo(0), Fe(II)
and Pd(II) complexes of a new aminobis(diphos-
phonite), PhN{P(OC6H4OMe-o)2}2. The molecular
structures of PhN{P(OC6H4OMe-o)2}2 (1), PhN
Recently we have reported the insertion of carbon
fragments into phosphorus–nitrogen bonds and also
the cleavage of phosphorus–nitrogen bonds in amino-
phosphines and aminobis(phosphines) [1,2]. The reac-
tions of aminophosphines and aminobis(phosphines)
with aldehydes either leads to the insertion of carbon
fragments into the phosphorus–nitrogen bonds or re-
sults in the formation of a-hydroxy phosphates through
phosphorus–nitrogen bond cleavage. Although, phos-
phorus–nitrogen bonds are moderately stable toward
moisture, lithium and Grignard reagents, during the
complexation reactions with transition metals, the P–N
*
Corresponding author. Tel.: 2225767181; fax: 2225723480/
912225767152.
E-mail address: krishna@iitb.ac.in (M.S. Balakrishna).
0022-328X/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.08.003

M.S. Balakrishna et al. / Journal of Organometallic Chemistry 689 (2004) 3388–3394
3389
1
{P(Se)-(OC6H4OMe-o)2}2 (4), Mo(CO)4[PhN{P(OC6H4-
OMe-o)2}2] (5) and the phosphorus–nitrogen bond
cleavage product, [CpFe(CO){P(O)(OC6H4OMe-o)2}-
{PhN(H)-(P(OC6H4OMe-o)2)}] (6) are also described.
ence of a terminal carbonyl group. The H NMR spec-
trum exhibits phenyl, cyclopentadienyl and methoxy
resonances at d 6.49, 4.75 and 3.68 ppm, respectively.
The 31P NMR spectrum of 6 shows an AX spin system
due to the presence of two types of phosphorus centers.
The low field resonance at 171 ppm is assigned to the
PhN(H)P(OC6H4OMe-o)2 unit whereas the resonance
due to P(O)(OC6H4OMe-o)2 appears at 129 ppm. The
2JP–Fe–P coupling is 120.8 Hz. In the mass spectrum,
the most intense fragment ion appears at m/e 812
[M+ + 1] which is the expected molecular ion. Further,
the structure of 6 was confirmed by a single crystal X-
ray diffraction study.
2. Results and discussion
The reaction of phenylaminobis(dichlorophosphine),
PhN(PCl2)2 with guaiacol in a 1:4 ratio in the presence
of triethylamine affords the aminobis(diphosphonite),
PhN{P(OC6H4OMe-o)2}2 (1). Treatment of 1 with
aqueous H2O2 (30% w/v) gives the dioxide derivative,
PhN{P(O)(OC6H4OMe-o)2}2 (2) in quantitative yield.
Aminobis(diphosphonite) 1 reacts smoothly with two
equivalents of elemental sulfur or selenium powder in
toluene under reflux conditions to give the correspond-
ing disulfide, PhN{P(S)(OC6H4OMe-o)2}2 (3) or disele-
nide, PhN{P(Se)(OC6H4OMe-o)2}2 (4) in good yield.
The elucidation of the structures of ligand 1 and the
chalcogen derivatives 2, 3 and 4 are based on NMR
(1H and 31P{1H}) spectroscopic data and elemental
analyses. The 31P{1H} NMRspectra of 1–4 exhibit single
resonances at 131.9, ꢀ12.3, 58.3, 64.7 and ꢀ12.3 ppm,
respectively. The diselenide derivative 4 shows a very
large 1JP–Se coupling of 1004 Hz. Further, the molecular
structures of 1 and 4 are confirmed by single crystal X-
ray structure determinations.
Ph
2P N
Me
2P N
X
F
CO
OC
Fe
Fe
Fe
Fe
P
P
PF2
F2P
X2
(X=OPh)
F2
N
Me
II
I
Treatment of M(COD)Cl2 (M = Pd, Pt) with 1:1 mo-
lar proportions of the ligand 1 in dichloromethane af-
ford the chelate complexes 7 and 8 in good yield. The
31P NMR spectra of 7 and 8 exhibit single resonances
at 76.3 and 48.5 ppm (1JPt–P = 2948 Hz), respectively.
The reaction of 1 with Mo(CO)6 in presence of two
equivalents of Me3NO Æ 2H2O in dichloromethane at
room temperature affords the chelate complex, cis-
[Mo(CO)4-{PhN(P(OC6H4OMe-o)2)2-jP,jP}] (5) in
good yield. The IR spectrum of 5 shows four bands in
the carbonyl region in the range 1897–2035 cmꢀ1 as ex-
pected for an {M(CO)4} moiety of C2v symmetry [17].
The 31P NMR spectrum of 5 shows a single resonance
at 147.8 ppm with a coordination shift of 15.9 ppm.
The structure of 5 was further confirmed by a single
crystal X-ray structure determination.
2.1. The crystal and molecular structures of 1, 4, 5 and 6
Perspective views of the molecular structures of com-
pounds 1, 4, 5 and 6 with the atom numbering schemes
are shown in Figs. 1–4, respectively. Crystal data and
details of the structure determinations are given in Table
1 while selected bond lengths and interbond angles ap-
pear in Table 2.
The reaction of ligand 1 with [CpFe(CO)2]2 in a 1:1
ratio in toluene under reflux conditions for 24 h afforded
a mononuclear complex [CpFe(CO){P(O)(OC6H4O-
Meo)2}{PhN(H)(P(OC6H4OMe-o)2)}] (6). During the
complexation, one of the P–N bonds of the ligand
undergoes moisture assisted hydrolysis to give two
different fragments, PhN(H)P(OC6H4OMe-o)2 and P(O)-
(OC6H4OMe-o)2. The aminophosphine acts as a r-do-
nor ligand whereas the P(O)(OC6H4OMe-o)2 fragment
forms a covalent bond with the metal center. Similar
reactions of [CpFe(CO)2]2 with aminophosphines of
the type PhN(PX2)2 (X = F [3], OPh [4]) led to the isola-
tion of dinuclear complexes containing PX2 and
RN = PX2 fragments bridging the two metal centers
with or without metal–metal bonds as shown in struc-
tures I and II. The complex 6 exhibits a sharp band in
its IR spectrum (mC„O) at 1973 cmꢀ1 indicating the pres-
Fig. 1. Perspective view of compound PhN{P(OC6H4OMe-o)2}2 (1)
showing the atom numbering scheme. Thermal ellipsoids are drawn at
the 50% probability level and hydrogen atoms are omitted for clarity.

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M.S. Balakrishna et al. / Journal of Organometallic Chemistry 689 (2004) 3388–3394
Fig. 4. Perspective view of [CpFe(CO){P(O)(OC6H4OMe-o)2-
jP}{PhN(H)-(P(OC6H4OMe-o)2)-jP}] (6) showing the atom number-
ing scheme. Thermal ellipsoids are drawn at the 50% probability level
and hydrogen atoms are omitted for clarity.
Fig. 2. Perspective view of compound PhN{P(Se)(OC6H4OMe-o)2}2
(4) showing the atom numbering scheme. Thermal ellipsoids are drawn
at the 50% probability level and hydrogen atoms are omitted for
clarity.
aminobis(phosphines) [5], their dichalcogenides [18,19],
diimines [20,21] or metal complexes [22]. The non
˚
bonded Pꢁ ꢁ ꢁP separation in complex 5 [2.631(2) A] is
˚
shorter than that in free ligand 1 [2.868(2) A] due to
the chelation. The diselenide derivative 4, which has
crystallographically imposed C2 symmetry, shows a
˚
much larger Pꢁ ꢁ ꢁP separation of 3.027(2) A. The P@Se
˚
distance of 2.058(6) A in 4 is the shortest ever reported
for either monophosphineselenides or bis(phosphinese-
lenides). Interestingly, the compound 4 also shows the
1
largest JP–Se coupling reported to date (1004 Hz). The
1
shorter P@Se distance coupled with larger JP–Se value
is an indication of a higher s-character [23] of the lone
pair on phosphorus in free ligand 1 which is eventually
donated to selenium. Our predictions are of course not
absolute and further efforts to definitely unravel the
uncertainties would be warranted. The molybdenum
center in 5 is octahedral and the atoms of the MP2N ring
are essentially planar.
Fig. 3. Perspective view of compound [Mo(CO)4{PhN(P(OC6H4OMe-
o)2)2-jP,jP}] (5) showing the atom numbering scheme. Thermal
ellipsoids are drawn at the 50% probability level and hydrogen atoms
are omitted for clarity.
The formation of the iron complex 6 is an example of
a aminobis(phosphine) undergoing moisture-assisted
hydrolysis during complexation to give the protonated
aminophosphine and phosphineoxide fragments which
bind the metal center through a coordinate and a cova-
lent bond, respectively. Analogous reactions of
RN(PX2)2 (R = Me, X = F; R = Ph, X = OPh) with
[CpFe(CO)2]2 resulted in the formation of binuclear
complexes bridged by P–N cleavage fragments without
the oxidation of phosphorus centers to give [CpFe{l–
PF2}{l-F2PN(Me)PF2}{l-MeN@PF2}FeCp] (I), [Cp-
(OC)Fe{l–P(OPh2)}{l-(PhO)2P@N(Ph)-jP,jN}FeCp]
The unit cell of 5 contains two independent mole-
cules, one of which has crystallographically imposed
C2 symmetry, but the corresponding bond lengths and
bond angles in the two molecules are not significantly
different. The mean P–N bond distances in both 1 and
4 are comparable to those in molybdenum complex 5.
The P–N–P angle in the diselenide derivative 4 is larger
[127.5(1)ꢁ] when compared to the same in the free ligand
1 [116.1(1)ꢁ] whereas in the molybdenum complex the P–
N–P angle shrinks to 102.4(2)ꢁ due to the formation of a
strained four-membered chelate ring. However, the sum
of the angles around nitrogen in all these compounds is
359.9ꢁ which clearly indicates that the geometry around
nitrogen is strictly planar; a characteristic feature of
˚
(II), respectively. The P(1)–N distance [1.643(2) A] in 6
is slightly shorter than that in compounds 1, 4 and 5
which clearly indicates an enhancement of p-bonding
in the P–N unit as a result of there being only one

M.S. Balakrishna et al. / Journal of Organometallic Chemistry 689 (2004) 3388–3394
3391
Table 1
Crystallographic data for compounds 1, 4, 5 and 6
1
4
5
6
Formula
M
C34H33NO8P2
645.55
C34H33NO8P2Se2
803.47
C38H33MoNO12P2
853.53
C40H39FeNO10P2
811.51
Crystal size (mm)
Crystal system
Space group
0.19 · 0.17 · 0.11
Orthorhombic
P212121
10.2756(8)
10.8282(3)
29.013(5)
90
0.14 · 0.16 · 0.23
Monoclinic
C2/c
0.07 · 0.09 · 0.14
Monoclinic
C2/c
0.16 · 0.14 · 0.23
Triclinic
ꢀ
P1
˚
a (A)
20.264(3)
9.715(1)
19.131(3)
90
49.352 (2)
11.865(2)
19.647(5)
90
8.564 (2)
10.284(2)
22.518(5)
79.629(3)
80.091(3)
71.344(3)
1834.3(7)
2
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
90
90
115.431(2)
90
103.272(2)
90
3
˚
V (A )
3228.1(4)
4
1.328
3401.2(9)
4
1.569
11197(3)
12
1.519
Z
Dc (g cmꢀ3
)
1.469
0.56
l (mmꢀ1
T (K)
Total no. reflections
)
0.187
100(2)
2.32
100(2)
0.502
100(2)
100(2)
15829
8064
7972
5691
14689
4103
34065
8055
No. unique reflections
Rint
0.0475
0.0556
0.0208
0.0263
0.0719
0.0459
0.0231
0.0459
0.1215
1.037
R
R0
Goodness of fit
0.065
1.095
0.0696
1.057
0.1107
1.011
phosphorus center to interact with the nitrogen lone
pair. The iron center is in a tetrahedral environment
with a typical piano stool arrangement. The Fe–P(1)
4. Experimental
All experimental manipulations were carried out un-
der an atmosphere of dry nitrogen or argon using Sch-
lenk techniques. All the solvents were purified by
conventional procedures and distilled prior to use. Phe-
nylaminobis(dichlorophosphine) was prepared accord-
˚
and Fe–P(2) distances are 2.158(1) and 2.191(1) A while
the Fe–C (carbonyl) and P@O distances are 2.095(3) and
˚
1.495(2) A, respectively. The mean Fe–C distance
˚
(cyclopentadienyl carbons) is 1.759(3) A.
ing to the literature [24]. The H and 31P NMR (d in
1
ppm) spectra were obtained on a VXR300S spectrometer
operating at frequencies of 300 and 121 MHz, respec-
tively. The spectra were recorded in CDCl3 solutions
with CDCl3 as an internal lock; TMS and 85% H3PO4
were used as external standards for 1H and 31P{1H}
NMR, respectively. Positive shifts lie downfield of the
standard in all cases. Melting points of all compounds
were determined on Veego melting point apparatus and
were uncorrected. Mass spectra were recorded on MAS-
PEC (msco/9849) system. Microanalyses were carried
out on a Carlo Erba model EA 1112 elemental analyzer.
3. Conclusion
The aminobis(diphosphinite) (1) readily reacts with
chalcogens and transition metal precursors to give
appropriate derivatives in good yield. The diselenide
derivative 4, has the largest phosphorus–selenium cou-
pling (1JP–Se = 1004 Hz) and the shortest P–Se bond dis-
˚
tance of 2.058(6) A reported to date. This is an
indication of the higher s-character of the lone pair on
phosphorus in free ligand 1. Thus, the ligand 1 can be
used as a very effective p-acceptor ligand to stabilize
low-valent metals. The reaction of 1 with [CpFe(CO)2]2
leads to cleavage of one of the P–N bonds to give a
mononuclear Fe(II) complex 6. Surprisingly all reports
on metal-mediated P–N bond cleavage of amino-
bis(phosphines) have been reported with the same iron
derivative, [CpFe(CO)2]2. We recently reported the
moisture-assisted P–N bond cleavage of aminophos-
phine, Ph2N(H)PPh2 with a Pd(II) derivative to give
an hydrogen bonded dinuclear complex, Pd(l-
Cl)2(Ph2POHOPPh2)2 [8]. Further research on the
behavior of P–N bonds under various reaction condi-
tions is in progress in our laboratory.
4.1. Preparation of PhN{P(OC6H4OMe-o)2}2 (1)
A mixture of guaiacol, HOC6H4OMe-o (4.36 g, 35.15
mmol) and triethylamine (3.55 g, 35.15 mmol) in dieth-
ylether (40 ml) was added dropwise to a solution of
N,N0-bis(dichlorophosphino)aniline (2.596 g, 8.78
mmol) also in diethylether (140 ml) at 0 ꢁC with vigor-
ous stirring. Then the solution was allowed to warm to
room temperature and stirring was continued for 24 h.
The triethylamine hydrochloride was removed by filtra-
tion. The solvent was removed under reduced pressure
to give a white residue, which was crystallized from

3392
M.S. Balakrishna et al. / Journal of Organometallic Chemistry 689 (2004) 3388–3394
Table 2
Selected bond distances and bond angles for 1, 4, 5 and 6
mmol) also in acetone (10 ml) and the mixture was stir-
red for 4 h. The solvent was removed under reduced
pressure to give a white solid, which was crystallized
from a 1:1 mixture of dichloromethane/diethyl ether.
Yield: 68% (0.22 g); m.p. 170–172 ꢁC. Anal. Calc. for
C34H33NO10P2: C, 60.26; H, 4.90; N, 2.07. Found: C,
59.94; H, 4.84; N, 1.94%. 31P{1H} NMR (121 MHz,
CDCl3): d ꢀ12.6 (s).
˚
Bond lengths (A)
Bond angles (ꢁ)
Compound 1
P1–N
P2–N
1.696(2)
1.865(2)
1.651(2)
1.651(2)
1.657(2)
1.882(2)
1.445(3)
P1–N–P2
P1–N–C29
P2–N–C29
O1–P1–N
O3–P1–N
O5–P2–N
O7–P2–N
116.07(12)
122.46(16)
121.47(16)
97.20(10)
100.68(10)
96.19(10)
100.85(10)
P1–O1
P1–O3
P2–O5
P2–O7
N–C29
4.3. Preparation of PhN(P(S)(OC6H4OMe-o)2)2 (3)
Compound 4
P–N
Se–P
A mixture of aminobis(diphosphonite) 1 (0.6 g, 0.9
mmol) and sulfur (0.06 g, 0.9 mmol) in toluene (30 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 (1.5
ml), layered with 1 ml of n-hexane and kept at room tem-
perature to give colorless crystals of 3. Yield: 86% (0.57 g);
m.p.: 240 ꢁC (decomp.). Anal. Calc. for C34H33NO8P2S2:
C, 57.53; H, 4.69; N, 1.97; S, 9.04. Found: C, 57.22; H,
1.687(1)
2.058(6)
1.460(3)
1.589(3)
1.588(1)
P–N–C15
P–N–P_a
P_a–N–C15
Se–P–N
116.25(6)
127.51(12)
116.25(6)
116.18(6)
104.41(8)
99.31(5)
N–C15
P–O1
P–O3
O1–P–N
O3–P–N
Compound 5a
Mo1–P1
Mo1–P2
P1–N1
2.434(1)
2.460(1)
1.686(4)
1.626(3)
1.605(3)
1.688(4)
1.610(3)
1.618(3)
1.454(6)
P1–N1–P2
102.4(2)
130.0(3)
P2–N1–C29
P1–N1–C29
P1–Mo1–P2
P1–Mo1–C35
P1–Mo1–C36
P1–Mo1–C37
P1–Mo1–C38
P2–Mo1–C35
1
127.5(3)
65.02(4)
4.63; N, 1.83; S, 8.78%. H NMR (300MHz, CDCl3): d
6.78–7.72 (m, 21H, Ph), d 3.64 (s, 12H, OMe); 31P{1H}
NMR (121 MHz, CDCl3): d 58.3 (s).
P1–O3
P1–O1
98.51(14)
88.31(15)
165.83(15)
95.32(13)
162.39(13)
P2–N1
P2–O7
4.4. Preparation of PhN{P(Se)(OC6H4OMe-o)2}2 (4)
P2–O5
N1–C29
A mixture of compound 1 (0.6 g, 0.9 mmol) and sele-
nium powder (0.49 g, 1.8 mmol) in toluene (30 ml) was
heated under reflux for 10 h. The solution was then
cooled to 25 ꢁC and filtered to remove any undissolved
selenium. The solvent was removed under reduced pres-
sure to give a sticky residue. The residue was dissolved
in 3 ml of CH2Cl2, layered with 1 ml of n-hexane and
kept at room temperature to afford colorless crystals
of 4. Yield: 72% (0.57 g); m.p.: 254–256 ꢁC. Anal. Calc.
for C34H33NO8P2Se2: C, 50.82; H, 4.14; N, 1.74. Found:
C, 50.56; H, 4.13; N, 1.79%. 1H NMR (300MHz,
CDCl3): d 6.85–7.45 (m, 21H, Ph), d 3.67 (s, 12H,
OMe); 31P1H NMR (121 MHz, CDCl3): d 64.7 (s),
1JP–Se = 1004 Hz
Mean Mo–C
Mean C–O(carbonyl)
P2–Mo1–C36
P2–Mo1–C37
P2–Mo1–C38
95.34(15)
101.46(15)
86.84(13)
Compound 6
Fe–P1
Fe–P2
2.158(1)
2.191(1)
1.643(2)
1.628(2)
1.625(2)
1.638(2)
1.645(2)
1.495(2)
1.411(3)
1.759(3)
1.136(3)
P1–N–C16
P1–N–H1N
C16–N–H1N
Fe–P1–N
132.18(16)
111.45
115.72
P1–N
P1–O1
P1–O2
P2–O5
P2–O6
P2–O9
N–C16
Fe–C41
O10–C41
114.00(7)
121.62(7)
98.46(3)
92.15(8)
86.46(9)
Fe–P2–O9
P1–Fe–P2
P1–Fe–C41
P2–Fe–C41
Mean Fe–C(Cp)
2.095(3)
4.5. Preparation of [Mo(CO)4{PhN(P(OC6H4O-
Me-o)2)2}] (5)
a
Values are given for molecule I only; these do not vary signifi-
cantly for molecule II.
To a mixture of 1 (0.23 g, 0.35 mmol) and Mo(CO)6
(0.1 g; 0.37 mmol) in dichloromethane (10 ml) was added
Me3NO Æ 2H2O (0.087 g, 0.78 mmol) in methanol (10 ml)
and the mixture was stirred at room temperature for 18 h.
The solution was concentrated to 3 ml and 1 ml of n-hex-
ane was added. Cooling this solution to 0 ꢁC gave 5 as yel-
low crystals. Yield: 72% (0.22 g); m.p.: 168–170 ꢁC. Anal.
Calc. for C38H33NO12P2Mo: C, 53.7; H, 3.8; N, 1.64.
Found: C, 52.12; H, 3.7; N, 2.1%. IR(mC„O): 2035,
dichloromethane/n-hexane. Yield: 84% (4.78 g); m.p.
100–102 ꢁC. Anal. Calc. for C34H33NO8P2: C, 63.25;
H, 5.15; N, 2.17. Found: C, 63.40; H, 5.22; N, 2.14%.
1H NMR (300MHz, CDCl3): d 6.74–7.59 (m, 21H,
Ph), d 3.62 (s, 12H, OMe); 31P{1H} NMR (121 MHz,
CDCl3): d 131.9 (s).
4.2. Preparation of PhN{P(O)(OC6H4OMe-o)2}2 (2)
1
1931, 1897 cmꢀ1. H NMR (300 MHz, CDCl3): d 6.82–
Aqueous 30% H2O2 (0.3 g, 7.92 mmol) in acetone (5
ml) was added to aminobis(diphosphonite) 1 (0.6 g, 0.9
8.21 (m, 21H, Ph), d 3.79 (s, 12H, OMe); 31P{1H}
NMR (121 MHz, CDCl3): d 147.8 (s).

M.S. Balakrishna et al. / Journal of Organometallic Chemistry 689 (2004) 3388–3394
3393
4.6. Preparation of [CpFe(CO){P(O)(OC6H4O-
Me-o)2}{PhN(H)P(OC6H4OMe-o)2}] (6)
Bruker Kryoflexꢂ attachment of the Bruker APEX
CCD diffractometer. Full spheres of data were collected
using 606 scans in x (0.3ꢁ per scan) at u = 0, 120ꢁ and
240ꢁ and graphite-monochromated Mo Ka radiation
A mixture of compound 1 (0.185 g, 0.28 mmol) and
[CpFe(CO)2]2 (0.1 g, 0.28 mmol) in toluene (10 ml)
was heated under reflux for 24 h to give a dark brown
solution. The solvent was removed under reduced pres-
sure to give a dark brown residue. The residue was dis-
solved in CH2Cl2 (1.5 ml), layered with 1 ml of n-hexane
and kept at room temperature to give crystals of 6.
Yield: 61% (0.16 g); m.p.: 144–146 ꢁC. Anal. Calc. for
C34H33NO8P2S2 C, 58.32; H, 2.92; N, 0.68. Found: C,
2
˚
(k = 0.71073 A). The raw data were reduced to F values
˚
at a resolution of 0.75 A using the SAINT+ software
Æ
SAINT+, V. 6.35A, Bruker-AXS, Madison, WI, 2002æ
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 deterio-
1
58.56; H, 4.59; N, 1.48%. H NMR (300MHz, CDCl3):
d 6.49–7.58 (m, 21H, Ph), d 4.75 (s, 5H, Cp), 3.68 (s,
ration during the data collection (SADABS SADABS, V.
Æ
2.05, Bruker-AXS, Madison, WI, 2000æ). The structures
were solved by direct methods (SHELX-97) and refined
by full-matrix least-squares based on F2 using the SHEL-
12H, OMe); 31P{1H} NMR (121 MHz, CDCl3): d
171(2P, d) and 129(2P, d, JPP 120.8 Hz). MS (FAB):
2
812 (M+ + 1).
XTL
-
PLUS program package ÆSHELXTL
-PLUS, V. 6.10,
Bruker-AXS, Madison, WI 2000æ. Hydrogen atoms were
placed in calculated positions except for that attached to
nitrogen in 6 which was placed in the location provided
by a difference map. All were included as riding contribu-
4.7. Preparation
Me-o)2)2}] (7)
of
[PdCl2{PhN(P(OC6H4O-
˚
A solution of 1 (0.14 g, 0.22 mmol) in CH3CN (4 ml)
was added dropwise to a solution of in situ generated
Pd(CH3CN)2Cl2 (0.04 g, 0.22 mmol) also in CH3CN (8
ml) and the reaction mixture was stirred at room tem-
perature for 3 h. The solution was concentrated to 3
ml and 1 ml of n-hexane was added. Cooling this solu-
tion to 0 ꢁC gave 7 as yellow crystals. Yield: 81%
(0.15 g); m.p.: 120–122 ꢁC. Anal. Calc. for
C34H33Cl2NO8P2Pd: C, 49.1; H, 3.9; N, 1.2. Found: C,
tions (C–H = 0.95–0.98 A) with isotropic displacement
parameters 1.2–1.5 times those of the attached carbon
atoms. In 5, the crystallographic C2 symmetry imposed
on the molecule built on Mo(2) results in disorder of
the methoxyphenyl group built on C(46). Two orienta-
tions were deduced from difference maps and were con-
strained 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.
1
48.81; H, 4.33; N, 1.64%. H NMR (300 MHz, CDCl3):
d 6.75–7.54 (m, 21H, Ph), d 3.66 (s, 12H, OMe);
31P{1H}046 NMR (121 MHz, CDCl3): d 76.3 (s).
6. Supplementary material
4.8. [PtCl2{PhN(P(OC6H4OMe-o)2)2}] (8)
Full details of data collection and structure refine-
ment have been deposited with the Cambridge Crystal-
lography Data Centre, CCDC nos. 244091, 244092,
244093 and 244094 for compounds 1, 4, 5 and 6, respec-
tively. 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).
A solution of 1 (0.052 g, 0.8018 mmol) in CH3CN (5
mL) was added dropwise to a solution of [Pt(COD)Cl2]
(0.03 g, 0.8018 mmol) also in CH3CN (4 mL) and the
reaction mixture was stirred at room temperature for
3–4 h. The solution was then concentrated to 2 mL
and 1 mL of petroleum ether (b.p. 60–80 ꢁC) was added.
Cooling this solution to 0 ꢁC gave 8 as white crystalline
material. Yield: 95% (0.07 g); m.p.: 158–160 ꢁC. Anal.
Calc. for C34H33Cl2NO8P2Pt: C, 44.79; H, 3.64; N,
1
1.53. Found: C, 44.98; H, 3.38; N, 1.52%. H NMR
(300 MHz, CDCl3): d 6.77–7.60 (m, 21H, Ph), d 3.67
Acknowledgements
(s, 12H, OMe); 31P{1H} NMR (121 MHz, CDCl3): d
48.46 (s), JP–Pt = 2948 Hz.
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
and the Chemistry Department, Tulane University,
New Orleans, LA, USA for the support of the Crystal-
lography Laboratory. J.T.M. acknowledges the support
of the Louisiana Board of Regents through the Louisi-
ana Educational Quality Support Fund (Grant: LEQSF
(2002–2003)-ENH-TR-67) for purchase of the Bruker
1
5. X-ray crystallography
Crystals of compounds 1, 4, 5 and 6 suitable for X-ray
crystal analysis were mounted on Cryoloopsꢂ with Par-
atone oil and placed in the cold nitrogen stream of the

3394
M.S. Balakrishna et al. / Journal of Organometallic Chemistry 689 (2004) 3388–3394
[11] S.K. Mandal, G.A.N. Gowda, S.S. Krishnamurthy, M. Nethaji,
J. Chem. Soc. Dalton Trans. 5 (2003) 1016.
APEX diffractometer. We also thank the regional
Sophisticated Center (RSIC), IIT Bombay for recording
NMR spectra.
[12] S.K. Mandal, G.A.N. Gowda, S.S. Krishnamurthy, C. Zheng, S.
Li, N.S. Hosmane, Eur. J. Inorg. Chem. 8 (2002) 2047.
[13] K. Raghuraman, S.S. Krishnamurthy, M. Nethaji, J. Organomet.
Chem. 669 (2003) 79.
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