Transition metal (Group 6, Ru and Group 10) derivatives of aminophosphines, Ph2PN(H)R (R=Ph, C6H11)

Article abstract of DOI:10.1016/S0022-328X(03)00543-6

The reactions of aminophosphines with Group 6 metal carbonyls afford both mono-substituted and disubstituted complexes. The reaction of Ph₂PN(H)C₆H₁₁ with molybdenum tetracarbonyl derivative gives a mixture of cis and trans-isomers. The reaction of Ph₂PN(H)Ph with Pd(COD)Cl₂ leads to the P-N bond cleavage to give chloro bridged dimer, [Pd(PPh₂O)(PPh₂OH) (μ-Cl)]₂, whereas with Pt(COD)Cl₂, disubstituted cis-[PtCl₂{PPh₂N (H)R}₂]₂ was obtained. The reaction of Ph₂PN(H)C₆H₁₁ with RuCl₂(DMSO)₄ or RuCl₂(PPh₃)₃ leads to the formation of ionic complex, [RuCl{Ph₂PN(H)C₆ H₁₁}₃]Cl.

Full text of DOI:10.1016/S0022-328X(03)00543-6

Journal of Organometallic Chemistry 679 (2003) 116Á124
/
www.elsevier.com/locate/jorganchem
Transition metal (Group 6, Ru and Group 10) derivatives of
aminophosphines, Ph2PN(H)R (RꢀPh, C6H11)
/
Srinivasan Priya a, Maravanji S. Balakrishna a,*, Joel T. Mague b
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 3 June 2003; received in revised form 6 June 2003; accepted 6 June 2003
Abstract
The reactions of aminophosphines with Group 6 metal carbonyls afford both mono-substituted and disubstituted complexes. The
reaction of Ph2PN(H)C6H11 with molybdenum tetracarbonyl derivative gives a mixture of cis and trans-isomers. The reaction of
Ph2PN(H)Ph with Pd(COD)Cl2 leads to the PÃN bond cleavage to give chloro bridged dimer, [Pd(PPh2O)(PPh2OH)(m-Cl)]2,
/
whereas with Pt(COD)Cl2, disubstituted cis-[PtCl2{PPh2N(H)R}2]2 was obtained. The reaction of Ph2PN(H)C6H11 with
RuCl2(DMSO)4 or RuCl2(PPh3)3 leads to the formation of ionic complex, [RuCl{Ph2PN(H)C6H11}3]Cl.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Aminophosphine; Transition metal complexes; Metalloligands; PÃN bond; Cleavage; Trans-isomer
/
1. Introduction
P(III)Ã
/
N bonds in aminophosphines and aminobis(phos-
N bonds in the
phines) and also the cleavage of P(III)Ã
/
The transition metal chemistry of aminobis(phos-
phines), X2PN(R)PX2 [1] is well documented whereas
that of the corresponding aminophosphines, X2PN(H)R
is limited [2]. This is partly due to the sensitivity of the
reactions with aldehydes [7]. As a part of our interest on
aminophosphines [8] and of others [2c,9], we report here
the synthesis and structural investigations of aminophos-
phines with transition metal derivatives.
P(III)Ã/N bonds towards acid or base catalysed hydro
lysis during complexation reactions [3]. However, by
choosing appropriate substitutents on both phosphorus
and nitrogen centers P(III)Ã
stabilized towards lithium reagents [4]. The intramole-
cular donorÁacceptor properties of aminophosphines
/
N bonds can be even
2. Experimental
All manipulations were performed under anaerobic
conditions using Schlenk techniques. The ligands,
/
with a ferrocene backbone confirm that the aminopho-
sphines can stabilize the transition metals in both high-
valent (Ti group metals) and low-valent states (platinum
metals) and also they can act as both terminal and
bridging ligands [5]. The phosphinoamide complex,
[Zr{N(Ph)PPh2}4] is found to be an active catalyst for
the formation of elastomeric polypropylene in the
presence of methylaluminoxane [6]. Recently we have
reported on insertions of carbon fragments into the
Ph2PN(H)R (Rꢀ
precursors M(COD)Cl2 (Mꢀ
RuCl2(PPh3)3 [13], RuCl2(DMSO)4 [14], M(CO)4(NBD)
(MꢀMo [15], Cr [16]) and W(CO)4(pip)2 [17], were
/
Ph, [10] C6H11 [7]), and the metal
/Pd [11], Pt [12])
/
prepared according to the literature procedures.
Ni(CO)2(PPh3)2 was purchased from Strem Chemical
1
Co. The H and 31P-NMR spectra were recorded using
Varian VXR 300 and Bruker AMX 400 spectrometers
operating at the appropriate frequencies using tetra-
methylsilane and 85% H3PO4 as internal and external
references, respectively. Positive shifts lie downfield in
all cases. IR spectra were recorded on a Nicolet Impact
* Corresponding author. Fax: ꢁ91-22-2576-7152.
/
E-mail address: krishna@iitb.ac.in (M.S. Balakrishna).
0022-328X/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00543-6

S. Priya et al. / Journal of Organometallic Chemistry 679 (2003) 116Á
/
124
117
400 FT IR instrument in KBr matrix. Microanalyses
were performed on a Carlo Erba model 1112 elemental
analyser. The FAB mass spectra were recorded on JEOL
SX 102/DA-6000 mass spectrometer/Data system using
Argon/Xenon (6 kV, 10 mA) as FAB gas and high
resolution mass spectra (HRMS) on MASCPEC (msco/
9849) system. Melting points were determined in capil-
lary tubes and are uncorrected.
Hz), 6.05 (d, N-Ph-o, 2H, 3JHH
ꢀ
/
7.5 Hz), 4.20 (br, NH,
2H). 31P{H}-NMR (CD2Cl2): d 69.8 (s).
2.5. Synthesis of cis-[Mo(CO)4{PPh2N(H)C6H11}2]
(6)
A mixture of Mo(CO)4(HNC5H10)2 (0.050 g, 0.130
mmol) and Ph2PN(H)C6H11 (0.075 g, 0.264 mmol) in
CH2Cl2 (10 ml) was stirred at r.t. for 8 h. The solvent
was evaporated from the reaction mixture under re-
duced pressure and the residue was washed with n-
2.1. Synthesis of Cr(CO)4{PPh2N(H)R}2 (Rꢀ
/
Ph, 3;
C6H11, 4)
hexane (3ꢂ
/
5 ml) and was re-crystallized from CH2Cl2Á
/
A mixture of [Cr(CO)4(NBD)] (0.04 g, 0.156 mmol)
and Ph2PN(H)R (0.312 mmol) in n-hexane (10 ml) was
heated to reflux for 12 h. The reaction mixture was
cooled to room temperature (r.t.) and the yellow residue
n-hexane (1:3) mixture and kept at 0 8C to give
analytically pure sample of 6. Yield: 0.081 g (80%).
M.p.
C40H44N2O4P2Mo: C 62.02; H 5.72; N 3.62%. Found:
136Á
/
139 8C
(dec.).
Anal.
Calc.
for
was separated by filtration, washed with n-hexane (3ꢂ
/
5
C 62.17; H 5.63; N 3.56%. FTIR (KBr cmꢃ1): n(NH)
ml) and recrystallized from CH2Cl2Án-hexane (2:1)
/
1
3399s; n(CO) 2014s, 1928vs, 1913vs, 1882vs. H-NMR
mixture at 0 8C to get crystalline product of analytical
purity.
(CDCl3): d 7.61Á
/
7.36 (m, phenyl, 10H), 2.47Á0.88 (m,
/
cyclohexyl, 11H). 31P{H}-NMR (CDCl3): d 74.5 (s).
2.2. Cr(CO)4{PPh2N(H)Ph}2 (3)
2.6. Synthesis of W(CO)4{PPh2N(H)R}2 (Rꢀ
C6H11, 8)
/
Ph, 7;
Yield: 0.056 g (50%). M.p. 175Á177 8C (dec.). Anal.
/
Calc. for C40H32N2O4P2Cr: C 66.85; H 4.49; N 3.89%.
Found: C 66.51; H 4.56; N 3.79%. FTIR (KBr cmꢃ1):
n(NH) 3389s; n(CO) 2009vs, 1917vs, 1901vs, 1887vs.
A mixture of [W(CO)4(NHC5H10)2] (0.05 g, 0.107
mmol) and Ph2PN(H)R (0.210 mmol) in CH2Cl2 (10 ml)
was stirred at r.t. for 8 h. The reaction mixture was
evaporated under reduced pressure and the residue
1H-NMR (CDCl3): d 7.92Á
7.00 (m, PPh, 10H), 6.66 (t,
/
N-Ph-m, 2H), 6.50 (t, N-Ph-p, 1H), 5.95 (br s, N-Ph-o,
2H), 4.32 (br s, NH, 1H). 31P{H}-NMR (CDCl3): d
89.9 (s).
obtained was washed with n-hexane (5ꢂ
crystallized from CH2Cl2Án-hexane (2:1) mixture at
0 8C.
/
5 ml) and re-
/
2.3. Cr(CO)4{PPh2N(H)C6H11}2 (4)
Yield: 0.042 g (46%). M.p. 177Á180 8C (dec.). Anal.
/
2.7. W(CO)4{PPh2N(H)Ph}2 (7)
Yield: 0.083 g (91%). M.p. 141Á
Calc. for C40H32N2O4P2W: C 56.49; H 3.79; N 3.30%.
Calc. for C40H44N2O4P2Cr: C 65.75; H 6.07; N 3.83%.
Found: C 65.15; H 6.19; N 3.76%. FTIR (KBr cmꢃ1):
1
n(NH) 3399s; n(CO) 2009vs, 1912vs, 1892vs, 1846s. H-
/
144 8C (dec.). Anal.
Found: C 56.64; H 3.70; N 3.38%. FTIR (KBr cmꢃ1):
NMR (CDCl3): d 8.07Á
/
7.05 (m, phenyl, 10H), 2.09Á
/
0.78 (m, cyclohexyl, 11H). 31P{H}-NMR (CDCl3): d
94.4 (s).
1
n(NH) 3394s; n(CO) 2014s, 1922s, 1893vs, 1880vs. H-
NMR (CDCl3): d 7.67Á
/
7.25 (m, PPh, 10H), 6.84 (t, N-
Ph-m, 2H, 3JHH 8.1 Hz), 6.65 (t, N-Ph-p, 1H, 3JHH
ꢀ
/
ꢀ
/
7.7 Hz), 6.02 (d, N-Ph-o, 2H, 3JHH
ꢀ7.6 Hz), 4.37 (br s,
/
2.4. Synthesis of Mo(CO)4{PPh2N(H)Ph}2 (5)
NH, 1H). 31P{H}-NMR (CDCl3): d 50.7 (1JWP
Hz).
ꢀ253.1
/
A mixture of Mo(CO)4(NBD) (0.050 g, 0.166 mmol)
and Ph2PN(H)Ph (0.092 g, 0.333 mmol) in heptane (10
ml) was refluxed for 2 h. The redÁ
obtained was evaporated to dryness and dissolved in
CH2Cl2Án-hexane (1:3) mixture and kept at r.t. for 2 h
to give pale-yellow crystalline product 5. Yield: 0.051 g
(40%). M.p. 139Á142 8C (dec.). Anal. Calc. for
/
brown solution
2.8. W(CO)4{PPh2N(H)C6H11}2 (8)
/
Yield: 0.071 g, (70%). M.p. 129Á
/
132 8C (dec.). Anal.
/
Calc. for C40H44N2O4PW×/CH2Cl2: C 53.73; H 5.06; N
C40H32N2O4P2Mo: C 63.00; H 4.23; N 3.67%. Found:
C 63.18; H 4.26; N 3.43%. FTIR (KBr cmꢃ1): n(NH)
3.05%. Found: C 53.77; H 4.91; N 3.04%. FTIR (KBr
cmꢃ1): n(NH) 3384s; n(CO) 2014vs, 1912vs, 1872vs,
1
3385s; n(CO) 2019s, 1939vs, 1926vs, 1892vs. H-NMR
1826vs. 1H-NMR (CDCl3): d 7.83Á
/
7.18 (m, phenyl,
0.45 (m, C5H10 and cyclohexyl, 21H).
31P{H}-NMR (CDCl3): d 67.5 (1JWP
259.8 Hz).
(CD2Cl2): d 7.65Á
/
7.38 (m, PPh, 20H), 6.82 (t, N-Ph-m,
7.5
10H), 3.03Á
/
3
4H, JHH
3
7.5 Hz), 6.63 (t, N-Ph-p, 1H, JHH
ꢀ
/
ꢀ
/
ꢀ
/

118
S. Priya et al. / Journal of Organometallic Chemistry 679 (2003) 116Á124
/
2.9. Synthesis of Mo(CO)5{PPh2N(H)Ph} (9)
3.53%. Found: C 56.23; H 5.81; N 3.37%. FTIR (KBr
1
7.05
cmꢃ1): n(NH) 3399 s. H-NMR (CDCl3): d 8.07Á
/
A mixture of Mo(CO)6 (0.050 g, 0.189 mmol) and
Ph2PN(H)Ph (0.053 g, 0.189 mmol) in benzene (10 ml)
and the reaction mixture was heated at reflux for 12 h.
The solvent was evaporated under reduced pressure and
(m, phenyl, 10H), 2.09Á
/
2.04 (br m. CH, 1H,), 1.92Á
/
0.78
(m, cyclohexyl, 10H). 31P{H}-NMR (CDCl3): d 76.4 (s).
MS (FAB): 986 [Mꢁ].
the residue obtained was extracted with n-hexane (3ꢂ
/
7
2.12. Synthesis of [Pd(PPh2O)(PPh2OH)(m-Cl)]2
(12)
ml) and the solution was passed through celite and the
yellow filtrate was concentrated to 4 ml and cooled to
give crystalline product of 5 in 21% yield (0.030 g).
The pale-yellow mother liquor on further concentra-
tion and cooling gave the crystalline product 9. Yield:
A solution of Pd(COD)Cl2 (0.030 g, 0.105 mmol) in
CH2Cl2 (5 ml) was added dropwise to Ph2PN(H)Ph
(0.058 g, 0210 mmol) also in CH2Cl2 (4 ml) at r.t. The
resultant clear solution was stirred at r.t. for 2 h to give
turbid pale yellow solution. The reaction mixture was
filtered and the filtrate was evaporated under reduced
pressure and the residue obtained was washed with n-
0.035 g (36%). M.p. 120Á124 8C (dec.). Anal. Calc. for
/
C23H16NO5PMo: C 53.82; H 3.14; N 2.73%. Found: C
53.57; H 3.12; N 2.67%. FTIR (n cmꢃ1): n(NH) 3414s;
n(CO) 2076s, 1986vs, 1906vs. 1H-NMR (CDCl3): d
3
7.36 (m, PPh, 10H), 7.04 (t, N-Ph-m, 2H, JHH
7.72Á
/
ꢀ
/
hexane (3ꢂ
hexane (2:1) mixture at 0 8C to give the product 12.
Yield: 0.038 g (73%). M.p. 187Á190 8C (dec.). Anal.
Calc. for C48H42Cl2O4P4Pd2: C 52.87; H 3.88%. Found:
/
5 ml) and crystallized from CH2Cl2Án-
/
3
7.68 Hz), 6.82 (t, N-Ph-p, 1H, JHH
ꢀ7.32 Hz), 6.60 (d,
7.71 Hz), 4.18 (br s, NH, 1H).
31P{H}-NMR (CDCl3): d 73.0 (s). HRMS: 513.27
/
3
N-Ph-o, 2H, JHH
ꢀ
/
/
[Mꢁ].
C 52.76; H 3.86%. H-NMR (CDCl3): d 7.58Á
/7.22 (m,
1
phenyl). 31P{H}-NMR (CDCl3): d 79.0 (s).
2.10. Synthesis of trans-
[Mo(CO)4{PPh2N(H)C6H11}2] (10)
The reaction of Ph2PN(H)Ph (0.068 g, 0.250 mmol)
with K2PdCl4 (0.040 g, 0.120 mmol) in CH3CN (7 ml) at
r.t. for 6 h also yielded the product 12 (0.020 g, 33%).
A mixture of Mo(CO)6 (0.050 g, 0.189 mmol) and
Ph2PN(H)C6H11 (0.054 g, 0.189 mmol) in benzene (10
ml) was refluxed for 10 h. The solution was evaporated
to dryness under reduced pressure and the residue
obtained was dissolved in n-hexane (10 ml), passed
through celite and the yellow filtrate was concentrated
to 4 ml and cooled to 0 8C to give bright yellow crystals
2.13. Synthesis of [Pt{(PPh2O)2H}2] (13)
A solution of Ph2PN(H)Ph (0.040 g, 0.140 mmol) in
CH3CN (5 ml) was added to K2PtCl4 (0.030 g 0.072
mmol) in CH3CN (5 ml) and the clear solution obtained
was refluxed for 2 h, which resulted in the white
suspension. The reaction mixture was filtered and the
of 10. Yield: 0.045 g (29%). M.p. 152Á156 8C (dec.).
/
Anal. Calc. for C40H44N2O4P2Mo: C 62.02; H 5.72; N
3.61%. Found: C 61.91; H 5.72; N 3.66%. FTIR (KBr
cmꢃ1): n(NH) 3391s; n(CO) 1884vs. 1H-NMR (CDCl3):
white residue was washed with CH2Cl2 (2ꢂ
dried under vacuum and was identified as the complex
13. Yield: 0.025 g (35%). M.p. 249Á252 8C (dec.). Anal.
Calc. for C48H42O4P4Pt: C: 57.55; H 4.23%. Found C:
/
5 ml) and
/
d 7.72Á
/
7.34 (m, phenyl, 10H), 2.69Á0.76 (m, cyclohexyl,
/
11H). 31P{H}-NMR (CDCl3): d 85.2 (s).
The mother liquor on concentration and cooling to
0 8C gave pale yellow crystalline product of 6 in 20%
(0.020 g) yield.
57.22; H: 4.32%. 1H-NMR (DMSO-d6): d 7.79Á
/
7.27 (m,
3958
phenyl). 31P{H}-NMR (DMSO-d6): d 53.4 (1JPtP
Hz).
ꢀ
/
2.14. Synthesis of PtCl2{PPh2N(H)R}2 (Rꢀ
/
Ph, 14;
2.11. Synthesis of [RuCl{PPh2N(H)C6H11}3]Cl (11)
C6H11, 15)
Ph2PN(H)C6H11 (0.094 g, 0.330 mmol) in CH2Cl2 (5
ml) was added to a solution of RuCl2(DMSO)4 or
RuCl2(PPh3)3 (0.080 mmol) in CH2Cl2 (7 ml) at r.t. The
orange red reaction mixture was stirred at r.t. for 6 h.
The solvent was evaporated under reduced pressure to
A mixture of cis-[PtCl2(COD)] (0.030 g, 0.08 mmol)
and Ph2PN(H)R (0.16 mmol) in CH2Cl2 (5 ml) was
stirred for 6 h at r.t. The solvent was evaporated under
reduced pressure to give a sticky residue, which was
washed with n-hexane (2ꢂ
/
5 ml) and dissolved in a
give a sticky oil which was washed with n-hexane (2ꢂ
ml) and the residue obtained was crystallized from
CH2Cl2Án-hexane (2:1) mixture at 0 8C to give an
analytically pure sample of 11. Yield: 0.079 g (80%
with RuCl2(DMSO)4); 0.037 (76% with
RuCl2(PPh3)3). M.p. 164Á166 8C (dec.). Anal. Calc.
for C54H66N3P3RuCl2×2CH2Cl2: C 56.43; H 5.92; N
/
5
mixture of CH2Cl2Án-hexane (3:1) and cooled to 0 8C to
/
give analytically pure crystalline product.
2.15. PtCl2{PPh2N(H)Ph}2 (14)
/
g
/
Yield: 0.044 g (67%). M.p. 217Á
/
220 8C (dec.). Anal.
Calc. for C36H32N2Cl2P2Pt: C 52.69; H 3.93; N 3.41%.
/

S. Priya et al. / Journal of Organometallic Chemistry 679 (2003) 116Á
/
124
119
Found: C 52.65; H 3.89; N 3.39%. FTIR (KBr cmꢃ1):
Table 1
Crystallographic data for compounds 7, 10 and 14
1
n(NH) 3259 br.s. H-NMR (CDCl3): d 7.58Á
/
7.21 (m,
PPh, 10H), 6.88 (t, N-Ph-m, 2H, 3JHH
ꢀ
/
7.5 Hz), 6.75 (t,
7.2 Hz), 6.19 (d, N-Ph-o, 2H,
7
10
14
3
N-Ph-p, 1H, JHH
ꢀ
/
3JHH
(1JPtP
ꢀ
/
7.5 Hz). 31P{H}-NMR (CDCl3):
3927 Hz).
d
28.8
Empirical formula
C
40H32N2-
C40H44Mo-
N2O4P2
774.65
C36H32Cl-
2N2P2Pt
820.57
O4P2W
862.56
Triclinic
ꢀ
/
Formula weight
Crystal system
Space group
Orthorhombic
Monoclinic
P21(No. 4)
11.315(3)
14.378(4)
20.402(5)
¯
P1 (No. 2) Pbca (No. 61)
/
˚
2.16. PtCl2{PPh2N(H)C6H11}2 (15)
a (A)
14.927(2)
15.252(2)
18.530(3)
79.433(2)
67.885(2)
86.155(2)
3842.0(10)
2
16.681(3)
10.111(1)
22.075(4)
˚
b (A)
˚
c (A)
Yield: 0.059 g (81%). M.p. 182Á
Calc. for C36H44N2Cl2P2Pt×CH2Cl2: C 48.43; H 5.05; N
3.05%. Found: C 48.02; H 5.07; N 3.05%. FTIR (KBr
/
185 8C (dec.). Anal.
a (8)
b (8)
g (8)
Á/
Á/
Á/
Á/
/
97.604(4)
Á/
1
cmꢃ1): n(NH) 3245 br s. H-NMR (CDCl3): d 7.61Á
7.23 (m, PPh, 10H), 4.01 (br m, NH, 1H), 1.43Á0.77 (m.
cyclohexyl, 11H). 31P{H}-NMR (CDCl3):
29.6
(1JPtP
3951 Hz).
/
3
˚
V (A )
Z
3723.4(11)
4
3290.0(15)
4
/
D(calc.) (mg mꢃ3
)
1.500
1.382
0.71073
0.5
1.653
0.71073
4.6
d
Ka) a (A)
0.71073
3.1
100
˚
l(MoÁ
m (MoÁ
Temperature (K)
u minÁmax (8)
/
ꢀ
/
/
Ka) (mmꢃ1
)
ꢃ
/
173
100
/
1.2Á/28.3
1.9Á28.3
/
1.7Á28.3
/
b
R
0.0259
0.0821
0.0478,
7.5288
0.0551
0.1224
0.0384,
8.6238
0.0429
0.1111
0.0517,
19.4233
2.17. Synthesis of Ni(CO)2{PPh2N(H)C6H11)}2 (16)
WR
a, b
A mixture of Ni(CO)2(PPh3)2 (0.050 g, 0.078 mmol)
and Ph2PN(H)C6H11 (0.044 g, 0.156 mmol) in CH2Cl2
(10 ml) was stirred at r.t. for 12 h. The solution was
evaporated under reduced pressure and the residue
a
Graphite monochromated.
b
wꢀ
/
1/[s2(Fo)2ꢁ
/
(aP)2ꢁ
/bP]; Pꢀ
/
1/3[F2oꢁ2F2c].
/
obtained was washed with hot n-hexane (3ꢂ
give analytically pure sample of 16. Yield: 0.040 g (68%).
M.p. 179Á181 8C (dec.). Anal. Calc. for
C38H44N2O2P2Ni×CH2Cl2: C: 61.12; H: 6.05; N:
/
5 ml) to
/
/
3. Results and discussion
3.66%. Found: C: 60.97; H: 6.06; N: 3.47%. FTIR
1
(KBr cmꢃ1): n(NH) 3128vs; n(CO) 1997s; 1935s. H-
NMR (CDCl3): d 7.93Á
/
7.26 (m, phenyl, 10H), 2.99Á
/
1.16 (m. cyclohexyl, 11H). 31P{H}-NMR (CDCl3): d
22.2 (s).
The mononuclear metal carbonyl derivatives, cis-
[M(CO)4{PPh2N(H)R}2] (MꢀCr, RꢀPh, 3; C6H11,
4, MꢀMo, RꢀPh, 5; C6H11, 6, MꢀW, RꢀPh, 7;
2.18. X-ray crystallography
/
/
/
/
/
/
Crystals of compounds 7, 10, 12 and 14 were mounted
on Pyrex filaments with epoxy resin. Enraf-Nonius
CAD-4 diffractometer was used for the unit cell
determination and intensity data collection. The initially
obtained unit cell parameters were refined by accurately
centering randomly selected reflections in the 2u ranges
given in Table 1 (for 12 in Section 5). General
procedures for crystal alignment and collection of
intensity data on the Enraf-Nonius CAD-4 diffract-
ometer have been published [18]. Periodic monitoring of
check reflections showed stability of the intensity data.
Details of the crystal and data collection are given in the
Table 1. The data were corrected for Lorentz and
polarization effects [19]. The calculations were per-
formed with the SHELXTL PLUS [20] program package.
The non-hydrogen atoms were geometrically fixed and
allowed to refine using riding model and an empirical psi
scan absorption correction was employed [21].
C6H11, 8) were obtained by the displacement of either
olefins or piperidine from the tetra carbonyl derivatives.
The IR spectra of all the complexes, [M(CO)4L2] exhibit
four bands in the carbonyl region (1885Á )
2020 cmꢃ1
/
characteristic of the presence of cis-[M(CO)4] with C2v
symmetry. The 31P-NMR spectra of all the above
complexes exhibit single resonances, which are de-
shielded from the corresponding free ligands. The
coordination chemical shift value decreases considerably
from chromium to tungsten as expected. The structure
of complex cis-[W(CO)4{PPh2N(H)Ph}2] is established
by single crystal X-ray diffraction studies. The ORTEP
[22] diagram of complex 7 is shown in Fig. 1 and the
crystallographic data, selected bond distances and
angles are listed in Tables 1 and 2. There are two
molecules in the asymmetric unit but the corresponding
bond distances and angles are not the same as shown in

120
S. Priya et al. / Journal of Organometallic Chemistry 679 (2003) 116Á124
/
Fig. 1. (a) Perspective view of complex 7 drawn on 50% probability level. Hydrogen atoms are omitted for clarity. (b) Intermolecular CÃ
/
H
/
Á Á Á
/
OH
bonding interaction.
Table 2. The tungsten atom is in a distorted octahedral
environment and the bond angles around tungsten
The reaction of ligand 2 with equimolar quantity of
Mo(CO)6 afforded a mixture of cis-[Mo(CO)4{Ph2-
PN(H)C6H11}2] (6) and trans-[Mo(CO)4{Ph2PN-
(H)C6H11}2] (10) in 20 and 29% yields, respectively.
The IR spectrum of the trans isomer shows a single
band in the carbonyl region at 1884 cmꢃ1 and the 31P-
NMR spectrum shows a single resonance at 85.2 ppm
with a coordination shift of 49.1 ppm. Further the
structure of complex 10 was established by single crystal
X-ray diffraction studies. The ORTEP diagram of com-
plex 10 is shown in Fig. 2 and the crystallographic data
and the selected bond distances and angles are listed in
Tables 1 and 3, respectively. The molecule adopts a
regular octahedral geometry around molybdenum with
varies from 174.6(1)8 to 177.4(1)8. The PÃ
/
N bond
distance (1.692(3) A) is shorter than the Pauling scale
due to the PÃN multiple bonding. The WÃP and WÃ
bond distances are 2.488(1)Á2.499(1) A and 2.001(3)Á
˚
/
/
/C
˚
/
/
˚
2.041(3) A, respectively. In the lattice complex 7 shows
intermolecular hydrogen-bonding interactions through
phenyl hydrogens and the carbonyl oxygen atoms
˚
˚
(
/
dC(59)ÁÁÁO(2)
H(59) O(2) bond angleꢀ
Á Á Á
1(b).
/
ꢀ
/
3.186(4) A, dH(59)ÁÁÁO(2)
/
ꢀ
/
2.5856 A, C(59)Ã
/
/
/
/
121.478) as shown in Fig.
The reaction of 1 with equimolar quantity of
Mo(CO)6 in benzene yielded a mixture of mono-
substituted complex, Mo(CO)5{PPh2N(H)Ph} (9) and
all trans angles being 1808, whereas the cis angles vary
the
disubstituted
complex
cis-[Mo(CO)4{PPh2-
˚
from 87.8 to 92.28. The PÃ
within the range of 1.66Á
with PÃN multiple bonding. The MoÃ
/
N bond distance of 1.679 A is
N(H)Ph}2] (5) which were separated by fractional
crystallization. The 31P-NMR spectrum of complex 9
shows a single resonance at 73.0 ppm. The same
complex 5 was obtained by Kuhl et al. in the reaction
¨
of Mo(CO)4(NCEt)2 with 1 [2c].
˚
/
170 A expected for compounds
P bond distance
of 2.462 A is slightly shorter than that in trans-[Mo-
/
/
˚
˚
(CO)4(PPh3)2] (2.500 A) [23], trans-[Mo(CO)4-

S. Priya et al. / Journal of Organometallic Chemistry 679 (2003) 116Á
/
124
121
Table 2
Selected bond distances (A) and bond angles (8) for 7
Table 3
Selected bond distances (A) and bond angles (8) for 10
˚
˚
˚
Bond distances (A)
˚
Bond distances (A)
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
/
P(1)
P(2)
C(1)
C(2)
C(3)
C(4)
2.493(1)
2.499(1)
2.004(3)
2.001(3)
2.041(3)
2.025(3)
1.687(3)
1.691(3)
W(2)Ã
W(2)Ã
W(2)Ã
W(2)Ã
W(2)Ã
W(2)Ã
/
P(3)
2.496(1)
2.488(1)
2.011(3)
2.007(3)
2.030(3)
2.040(3)
1.699(3)
1.690(3)
MoÃ
MoÃ
PÃ
NÃ
/
P
2.462(1) MoÃ
2.046(3) PÃ
1.836(3) PÃ
1.461(4)
/
C(1)
2.039(3)
1.679(3)
1.826(3)
/
/P(4)
/C(2)
/
N
/
/
C(41)
C(42)
C(43)
C(44)
/
C(3)
C(15)
/
C(9)
/
/
/
/
/
Bond angles (8)
/
/
PÃ
PÃ
PÃ
P(_a)Ã
C(1)ÃMoÃ
C(1_a)ÃMoÃ
P(_a)ÃMoÃC(1_a)
C(1_a)ÃMoÃC(2_a)
/
MoÃ
MoÃ
MoÃ
/
C(1)
90.7(1) PÃ
180.0
PÃ
87.8(1) C(1)Ã
89.3(1) P(_a)Ã
180.0 MoÃ
C(1)Ã
89.8(1) C(2)ÃMoÃ
90.7(1) P(_a)ÃMoÃ
90.2(1)
/
MoÃ
/
C(2)
92.2(1)
89.3(1)
90.2(1)
87.8(1)
89.8(1)
180.0
P(1)Ã
/
N(1)
P(3)Ã
/
N(3)
/
/P(_a)
/
MoÃ
/
C(1_a)
P(2)Ã
/N(2)
P(4)Ã
/N(4)
/
/C(2_a)
/
MoÃ
/
C(2)
Bond angles (8)
/
MoÃ
C(1_a)
C(2)
/C(1)
/
MoÃ
/C(2)
P(1)Ã
P(1)Ã
P(1)Ã
P(1)Ã
P(1)Ã
P(2)Ã
P(2)Ã
P(2)Ã
P(2)Ã
C(1)Ã
C(1)Ã
C(1)Ã
C(2)Ã
C(2)Ã
C(3)Ã
/
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
W(1)Ã
/
P(2)
C(1)
C(2)
C(3)
C(4)
C(1)
C(2)
C(3)
C(4)
90.70(2) P(3)Ã
/
W(2)Ã
W(2)Ã
W(2)Ã
W(2)Ã
W(2)Ã
W(2)Ã
W(2)Ã
W(2)Ã
W(2)Ã
C(41)ÃW(2)Ã
C(41)ÃW(2)Ã
C(41)ÃW(2)Ã
C(42)ÃW(2)Ã
C(42)ÃW(2)Ã
C(43)ÃW(2)Ã
/
P(4)
89.9(2)
91.3(1)
174.6(1)
93.0(1)
85.7(1)
176.0(1)
87.3(1)
87.7(1)
94.6(1)
91.8(1)
88.4(1)
89.3(1)
91.6(1)
89.8(1)
177.7(1)
/
/
/
/C(2_a)
/
/
89.6(1)
174.8(1)
94.1(1)
85.8(1)
175.8(9)
90.1(1)
86.2(1)
93.5(1)
90.0(1)
89.6(1)
90.6(1)
91.1(1)
89.0(1)
179.7(1)
P(3)Ã
P(3)Ã
P(3)Ã
P(3)Ã
P(4)Ã
P(4)Ã
P(4)Ã
P(4)Ã
/
/
C(41)
C(42)
C(43)
C(44)
C(41)
C(42)
C(43)
C(44)
/
/
/
/C(2_a)
/
/
/
/
/
/
/
/C(2_a)
92.2(1)
/
/
/
/
/
/
/
/
/
/
/
/
/
/
nal bipyramidal geometry around the ruthenium(II)
center with two chlorides in axial positions and the
three phosphorus centers in the trigonal plane can not
be ruled out as the 31P-NMR spectrum will show a
single resonance.
/
/
/
/
/
/
/
/
/
/
/
/
/
/
C(2)
C(3)
C(4)
C(3)
C(4)
C(4)
/
/C(42)
/
/
/
/
C(43)
C(44)
C(43)
C(44)
C(44)
/
/
/
/
The reaction of 1 with Pd(COD)Cl2 resulted in the
formation of chloro bridged dinuclear complex, [Pd(m-
/
/
/
/
/
/
/
/
/
/
/
/
Cl)(PPh2O)(PPh2OH)]2 (12) through the PÃ
/
N bond
cleavage. The 31P-NMR spectrum of the complex shows
a single resonance at 79.0 ppm. The absence of nNH in
the IR and the NÃ
indicates the PÃN bond cleavage. The reaction of
/
Ph protons in the 1H-NMR spectrum
/
K2PdCl4 with two equivalents of 1 in acetonitrile also
leads to the formation of the same complex 12 in good
yield. Dixon and Rattery have reported the formation of
the same complex 12 in the reaction of K2PdCl4 with
Ph2HP(O)/PPh2Cl in waterÁacetone [26]. When the cis-
/
Cl2Pd(PPh2OCH2)2-nBu4calixarene was kept in chlori-
nated solvent it undergoes decomposition to give the
same complex 12 [27]. The structure of complex 12 was
confirmed by single crystal X-ray diffraction studies and
the molecular structure (Figure S1 in Section 5) is
similar to the one reported by Ghaffer et al. [28]. The
reaction probably proceeds via the formation of the
intermediate PdCl2(Ph2POH)2 complex. The PÃ
/
N bond
Fig. 2. ORTEP diagram of complex 10 (50% probability ellipsoids).
Hydrogen atoms are omitted for clarity.
cleavage takes place during coordination to form
Ph2POH which in turn forms the chloro bridged
complex 12 as shown in Scheme 1.
˚
(PhPC4Me4)2] (2.480 A), [24] and trans-[Mo(CO)4-
˚
(PCy3)2] (2.544 A) [25].
The reaction of 1 with K2PtCl4 affords the platinum
complex, [Pt{(PPh2O)2H}2] (13), via the cleavage in PÃ
/
N bond. The 31P-NMR spectrum of 13 shows a single
resonance at 53.4 ppm with a 1JPtP coupling of 3958 Hz.
Reaction of ligands 1 and 2 with cis- [PtCl2(COD)] in
dichloromethane in 2:1 molar ratio at r.t. afford cis-
Interestingly, the reaction of ligand 2 with either
RuCl2(DMSO)4 or RuCl2(PPh3)3 in 4:1 molar ratio
yielded the ionic complex, [RuCl{Ph2PN(H)C6H11}3]Cl
(11). The 31P-NMR spectrum of complex 11 shows a
single resonance at 76.4 ppm indicating the tetrahedral
nature of the molecule and the mass spectrum of the
complex shows a molecular ion peak corresponding to
the cationic species. The rare low-coordination of
ruthenium in the molecule is attributed to the sterically
demanding aminophosphine ligands. However, a trigo-
[PtCl2{PPh2N(H)R}2] (RꢀPh, 14 and C6H11, 15) in
/
good yields. The 31P-NMR spectra of complexes 14 and
15 show single resonances at 28.8 and 29.6 ppm with
1JPtP coupling of 3927 and 3951 Hz, respectively. The
structure of the complex 14 has been established by
single crystal X-ray diffraction studies and the perspec-

122
S. Priya et al. / Journal of Organometallic Chemistry 679 (2003) 116Á124
/
Table 4
Selected bond distances (A) and bond angles (8) for 14
˚
˚
Bond distances (A)
Pt(1)Ã
Pt(1)Ã
Pt(1)Ã
Pt(1)Ã
/
Cl(1)
Cl(2)
P(1)
2.348(2) Pt(2)Ã
2.362(2) Pt(2)Ã
2.221(2) Pt(2)Ã
2.254(2) Pt(2)Ã
/
Cl(3)
Cl(4)
P(3)
2.254(2)
2.353(2)
2.253(2)
2.239(2)
1.634(8)
1.669(8)
/
/
/
/
/P(2)
/P(4)
P(1)Ã
/
N(1)
1.667(8) P(3)Ã
/
N(3)
P(2)Ã
/
N(2)
1.686(9) P(4)Ã
/
N(4)
Bond angles (8)
Cl(1)Ã
Cl(1)Ã
Cl(1)Ã
Cl(2)Ã
Cl(2)Ã
P(1)ÃPt(1)Ã
/
Pt(1)Ã
Pt(1)Ã
Pt(1)Ã
Pt(1)Ã
Pt(1)Ã
/
Cl(2)
P(1)
P(2)
P(1)
P(2)
86.6(1) Cl(3)Ã
84.4(1) Cl(3)Ã
170.0(1) Cl(3)Ã
170.7(1) Cl(4)Ã
86.9(1) Cl(4)Ã
102.3(1) P(3)ÃPt(2)Ã
/
Pt(2)Ã
Pt(2)Ã
Pt(2)Ã
Pt(2)Ã
Pt(2)Ã
/
Cl(4)
P(3)
P(4)
P(3)
P(4)
86.6(1)
87.6(1)
174.1(1)
172.7(1)
90.8(1)
95.4(1)
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
P(2)
/
/
P(4)
Scheme 1.
tive view of the molecule is shown in Fig. 3. The
asymmetric unit contains two molecules but the corre-
sponding bond distances and bond angles of two
molecules are not significantly same as shown in Table
4. The platinum metal is in distorted square planar
geometry and the angles around platinum vary
˚
(CH2Ph)CH2CH2(CH2Ph)NPPh2}] (2.241(3) A) [8b],
but longer when compared to the phosphinite complexes
like, cis-[PtCl2{PPh2(OC10H6)(CH2)-(OC10H6)PPh2}]
˚
(2.226(3) A) [8f] and shorter when compared to cis-
˚
[PtCl2(PMe3)2] (2.315(10) A) [29]. Complex 14 exhibits
three different types of intermolecular hydrogen-bond-
ing involving Cl and different phenyl hydrogens
from 84.4(1)8 to 102.3(1)8. The average PÃ
/
N bond
distance (1.664(8) A) is smaller than the sum of Pauling
˚
˚
˚
˚
(
/
dC(27)ÁÁÁCl(3)
H(27) Cl(3) bond angleꢀ
Á Á Á
3.399(11) A, dH(32)ÁÁÁCl(1)
Cl(1) bond angleꢀ145.678; dC(54)ÁÁÁCl(4)
/
ꢀ
/
3.586(11) A, dH(27)ÁÁÁCl(3)
/
ꢀ
/
2.7131 A, C(27)Ã
/
covalent radii (1.77 A) as expected due to PÃ
/
N multiple
˚
/
/
/
153.128; dC(32)ÁÁÁCl(1)
/
ꢀ
/
bonding. The average PtÃP bond distance (2.242(2) A)
in complex 14 is comparable with similar Pt(II)
aminophosphine complexes such as, cis-[PtCl2{Ph2PN-
/
˚
˚
/
ꢀ
/
2.5712 A, C(32)Ã
/
H(32)
˚
3.701(11) A,
/
Á Á Á
/
/
/
ꢀ
/
Fig. 3. (a) ORTEP diagram of complex 14, ellipsoids are drawn on 50% probability level. Hydrogen atoms are omitted for clarity. (b) Cl
intermolecular H bonding interactions.
/
Á Á Á
/
HÃC
/

S. Priya et al. / Journal of Organometallic Chemistry 679 (2003) 116Á
/
124
123
˚
dH(54)ÁÁÁCl(4)
/
ꢀ
/
2.7699 A, C(54)Ã
/
H(54)
/
Á Á Á
/
Cl(4) bond an-
support of the Tulane Crystallography Laboratory. We
also thank the Regional Sophisticated Instrumentation
Center (RSIC), Bombay and Lucknow for NMR and
mass spectra, respectively, and Sophisticated Instrumen-
tation Facility (SIF) Bangalore, for NMR spectra.
gleꢀ166.698) as shown in the Fig. 3(b).
/
The reaction of ligand 2 with the Ni(0) derivative,
Ni(CO)2(PPh3)2 in 2:1 molar ratio afforded cis-
[Ni(CO)2{PPh2N(H)C6H11}2] (16) with the displace-
ment of coordinated Ph3P groups. The IR spectrum
shows two bands for CO at 1997 and 1935 cmꢃ1
indicating the presence of two CO groups. The 31P-
NMR spectrum shows single resonance at 22.2 ppm
References
with the coordination shift of ꢃ13.9 ppm.
/
[1] (a) M.S. Balakrishna, V. Sreenivasa Reddy, S.S. Krishnamurthy,
J.F. Nixon, J.C.T.R. Burckett St. Laurent, Coord. Chem. Rev.
129 (1994) 1.;
(b) K. Raghuraman, S.S. Krishnamurthy, M. Nethaji, J. Orga-
nomet. Chem. 669 (2003) 79;
4. Conclusion
(c) K. Raghuraman, S.S. Krishnamurthy, M. Nethaji, J. Chem.
Soc. Dalton Trans. (2002) 4289;
Several Group 6, ruthenium and Group 10 complexes
of Ph2PN(H)R (RꢀPh, C6H11) have been prepared.
Molybdenum and tungsten complexes have been struc-
/
(d) S.K. Mandal, G.A.N. Gowda, S.S. Krishnamurthy, C. Zheng,
S. Li, N.S. Hosmane, Eur. J. Inorg. Chem. (2002) 2047.
[2] (a) D. Fenske, B. Maczek, K. Maczek, Z. Anorg. Allg. Chem. 623
(1997) 1113;
turally characterized. The reactions of Ph2PN(H)R with
Pd(COD)Cl2 as well as K2MCl4 (Mꢀ/Pd, Pt) leads to
(b) O. Kuhl, P.C. Junk, E. Hey-Hawkins, Z. Anorg. Allg. Chem.
¨
626 (2000) 1591;
the cleavage of PÃN bond and results in the formation
/
of [Pd(PPh2O)(PPh2OH)(m-Cl)]2 and [Pt{(PPh2O)2H}2].
The reaction of Ph2PN(H)R with Pt(COD)Cl2 gives the
expected cis-[PtCl2(PPh2N(H)R)2] which has been struc-
turally characterized. Both tungsten(0) and platinum(II)
derivatives show intermolecular hydrogen-bonding in-
teractions. The carbonyl complexes, Ni(CO)2(PPh2-
N(H)R)2 and M(CO)4(PPh2N(H)R)2 can be used as
metallo-ligands for making heterobimetallic complexes
with different by utilizing NH functionality. Similarly,
the cis-dichloro platinum complex can act as a potential
synthon to design high nuclearity clusters with the
transition metals and the work in this direction is in
progress in our laboratory.
(c) O. Kuhl, S. Blaurock, J. Sieler, E. Hey-Hawkins, Polyhedron
¨
20 (2001) 111;
(d) G. Suss-Fink, M.A. Pellingeelli, A. Tiripicchhio, J. Organo-
met. Chem. 320 (1987) 101.
[3] (a) A.D. Burrows, M.F. Mahon, M.T. Palmer, M. Varrone,
Inorg. Chem. 41 (2002) 1695;
(b) M.S. Balakrishna, S.S. Krishnamurthy, Ind. J. Chem. 30A
(1991) 536;
(c) M.G. Newton, R.B. King, M. Chang, J. Gimeno, J. Am.
Chem. Soc. 100 (1978) 1632;
(d) J. Geicke, I.P. Lorenz, P. Murschel, K. Polborn, Z.
Naturforsch. 52B (1997) 593.
[4] M.T. Ashby, Z. Li, Inorg. Chem. 31 (1992) 1321.
[5] F. Jakle, M. Mattner, T. Priermeier, M. Wagner, J. Organomet.
Chem. 502 (1995) 123.
[6] O. Kuhl, T. Koch, F.B. Somoza, P.C. Junk, E. Hey-Hawkins, D.
¨
Plat, M.S. Eisen, J. Organomet. Chem. 604 (2000) 116.
[7] (a) S. Priya, M.S. Balakrishna, J.T. Mague, Inorg. Chem.
Commun. 4 (2001) 437;
5. Supplementary material
(b) S. Priya, M.S. Balakrishna, J.T. Mague, S.M. Mobin, Inorg.
Chem. 42 (2003) 1272.
Full details of data collection and structure refine-
ment have been deposited with the Cambridge Crystal-
lographic Data Center, CCDC reference numbers
208304, 208306 and 208305 for compounds 7, 10 and
14, respectively. Copies of this information may be
obtained free of charge from the Director, CCDC, 12
[8] (a) M.S. Balakrishna, K. Ramaswamy, R.M. Abhyankar, J.
Organomet. Chem. 560 (1998) 131;
(b) M.S. Balakrishna, R.M. Abhyankar, J.T. Mague, J. Chem.
Soc. Dalton Trans. (1999) 1407;
(c) M.S. Balakrishna, R. Panda, J.T. Mague, Inorg. Chem. 40
(2001) 5620;
(d) M.S. Balakrishna, R.M. Abhyankar, M.G. Walawalker,
Tetrahedron Lett. 42 (2001) 2733;
Union Road, Cambridge, CB2 1EZ, UK (Fax: ꢁ44-
/
1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
(e) M.S. Balakrishna, M.G. Walawalker, J. Organomet. Chem.
628 (2001) 76;
(f) M.S. Balakrishna, R. Panda, J.T. Mague, J. Chem. Soc.
Dalton Trans. (2002) 4617.
[9] (a) P. Braunstein, M.D. Fryzuk, M.L. Dall, F. Naud, S.J. Rettig,
F. Speiser, J. Chem. Soc. Dalton Trans. (2000) 1067;
(b) S.M. Aucott, A.M.Z. Slawin, J.D. Woollins, Polyhedron 22
(2003) 361;
Acknowledgements
The Department of Science and Technology (DST)
and the Council of Scientific and Industrial Research
(CSIR), New Delhi, are acknowledged for the financial
support of this work. SP is thankful to CSIR, New
Delhi, for JRF and SRF fellowships. We thank the
Department of Chemistry, Tulane University for the
(c) S.K. Mandal, G.A.N. Gowda, S.S. Krishnamurthy, M.
Nethaji, J. Chem. Soc., Dalton Trans. (2003) 1016.
[10] W. Wiegrabe, H. Bock, Chem. Ber. 101 (1968) 1414.
[11] D. Drew, J.R. Doyle, Inorg. Synth. 13 (1972) 48.
[12] D.A. White, Inorg. Synth. 13 (1972) 52.
[13] P.R. Hoffman, K.G. Caulton, J. Am. Chem. Soc. 97 (1975) 4221.

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S. Priya et al. / Journal of Organometallic Chemistry 679 (2003) 116Á124
/
[14] I.P. Evans, A. Spencer, G. Wilkinson, J. Chem. Soc. Dalton
Trans. (1973) 204.
[15] R.B. King, Inorg. Chem. 2 (1963) 936.
[23] G. Hogarth, T. Norman, Inorg. Chim. Acta 254 (1997) 167.
[24] K.W. Muir, F.Y. Pettilon, R. Rumin, P. Schollhammer, J.
Talarmin, J. Organomet. Chem. 622 (2001) 297.
[25] E.C. Alyea, G. Ferguson, S. Kannan, Acta Crystallogr. C 52
(1996) 765.
[16] M.A. Bennett, L. Pratt, G. Wilkinson, J. Chem. Soc. (1961) 2037.
[17] D.J. Darensbourgh, R.L. Kump, Inorg. Chem. 17 (1978) 2680.
[18] K. Harms, S. Wocadlo, Program to Extract Intensity Data from
Enraf-Nonius CAD-4 Files, University of Marburg, Marburg,
Germany, 1987.
[26] (a) K.R. Dixon, A.D. Rattery, Can. J. Chem. 49 (1971) 3997;
(b) K.R. Dixon, A.D. Rattray, Inorg. Chem. 16 (1977) 209.
[27] D.R. Evans, M. Huang, J.C. Fettinger, T.L. Williams, Inorg.
Chem. 41 (2002) 5986.
[19] M.C. Burla, M. Camalli, G. Cascarano, C. Giacovazzo, G.
Polidori, D. Viterbo, Appl. Crystallogr. 22 (1989) 389.
[20] Bruker AXS, Madison, WI, 1995.
[28] T. Ghaffer, A. Kieszkiewicz, S.C. Nyburg, A.W. Parkins, Acta
Crystallogr. C50 (1994) 697.
[21] J.T. Mague, C.L. Lloyd, Organometallics 7 (1988) 983.
[22] L.J. Farrugia, J. Appl. Cryst. 30 (1997) 565.
[29] G.G. Messmer, E.L. Amma, J.A. Ibers, Inorg. Chem. 6 (1967)
725.