M.S. Balakrishna, M.G. Walawalker / Journal of Organometallic Chemistry 628 (2001) 76–80
77
2. Experimental
in dry hexane (15 ml) for 24 h after which it was filtered
hot. The filtrate was then cooled to 0°C to give analyt-
ically pure products in good yield.
2.1. General considerations
2. Yield 98%, m.p. 150°C. Anal. Found: C, 61.8; H,
4.8; N, 4.4. Calc. for C32H30N2O4P2Cr: C, 61.9; H, 4.8;
N, 4.5%. IR (KBr, cm−1): w(CO) 1874(vs), 1913(br),
All experimental manipulations were performed un-
der the atmosphere of dry nitrogen. Standard Schlenk
and vacuum line techniques were used. Solvents were
1
2012(vs). H-NMR (CDCl3): l 7.26 (m, 20H, phenyl),
dried and distilled prior to use. The H- and 31P-NMR
3.46 (dd, 4H, CH2CH2), 2.46 (t, 6H, N-CH3). 31P{1H}-
NMR (CDCl3): l 111.1 (s, 2P).
1
spectra were recorded on a VXR 300 spectrometer
operating at the appropriate frequencies using
tetramethylsilane and 85% H3PO4 as internal and exter-
nal references, respectively. CDCl3 was used as both
solvent and internal lock. Positive shifts lie downfield in
all cases. Infrared spectra were recorded in nujol mull
or KBr disc. Microanalyses were carried out in the
Department of Chemistry, IIT, Bombay.
3. Yield 63%, m.p. 129–130°C. Anal. Found: C, 57.8;
H, 4.5; N, 4.1. Calc. for C32H30N2O4P2Mo: C, 57.8; H,
4.5; N, 4.2%. IR (KBr, cm−1): w(CO) 1874(vs), 1894(s),
1
1926(vs), 2019(vs). H-NMR (CDCl3): l 7.26 (m, 20H,
phenyl), 3.48 (dd, 4H, CH2CH2), 2.48 (t, 6H, N-CH3).
31P{1H}-NMR (CDCl3): l 91.7 (s, 2P).
2.5. Preparation of
2.2. Starting compounds
[W(CO)4{Ph2PN(CH3)CH2CH2(CH3)NPPh2}] (4)
N,N%-Dimethylethylenediamine was obtained from
Lancaster Synthesis Ltd, and used without purification.
[M(CO)4(NBD)], (M=Cr [17], Mo [18]) [W(CO)4(pip)2]
[19], [MCl2(COD)] (M=Pd [20] or Pt [21]) and [Re-
Br(CO)3(NCMe)2] [22] were prepared according to pub-
lished procedures or with minor changes thereof.
A mixture of 1 (0.050 g, 0.11 mmol) and
[W(CO)4(pip)2] (0.050 g, 0.10 mmol) was heated under
reflux in dry CH2Cl2 (10 ml) for 6 h. The solution was
concentrated to about 5–7 ml under reduced pressure
and diluted with 2 ml hexane. Cooling to 0°C gives
analytically pure product in 67% yield, m.p. 130–
132°C. Anal. Found: C, 51.0; H, 3.9; N, 3.6. Calc. for
C32H30N2O4P2W: C, 51.1; H, 4.0; N, 3.7%. IR (KBr,
cm−1): w(CO) 2010(s) 1952(br), 1986(s). 1H-NMR
(CDCl3): d 7.08 (m, 20H, phenyl), 3.01 (dd, 4H,
CH2CH2), 2.31 (t, 6H, N-CH3). 31P{1H}-NMR
2.3. Preparation of Ph2PN(CH3)CH2CH2N(CH3)PPh2
(1)
The above ligand was prepared by modifying the
procedure of Mortreux et al. [23] as follows.
1
(CDCl3): l 75.1 (s, 2P), JPꢀW=258.6 Hz.
A solution of PPh2Cl (2.18 g, 9.89 mmol) in dry
diethyl ether (30 ml) was added with stirring to a
solution of N,N%-dimethylethylenediamine (0.871 g,
9.89 mmol) at −10°C. The stirring was continued for 3
h and the solution was warmed to 0°C and Et3N (2.1 g,
20.75 mmol) in dry diethyl ether (20 ml) was added
followed by the dropwise addition of PPh2Cl (2.18 g,
9.89 mmol) in a mixture of diethyl ether (25 ml) and
hexane (15 ml). Stirring was continued for 24 h at room
temperature (r.t.). The reaction mixture was then
filtered. The white solid obtained was consecutively
washed with water, MeOH and diethyl ether and dried
under vacuum. The compound was crystallized from a
1:1 mixture of CH2Cl2–hexane. (3.55 g, 78%). m.p.
184–187°C. Anal. Found: C, 73.6; H, 6.6; N, 6.1. Calc.
for C28H30N2P2: C, 73.7; H, 6.6; N, 6.1%. 1H-NMR
(CDCl3): l 6.82–7.41 (m, 20H, phenyl), 3.28 (s, 4H,
CH2CH2); 2.44 (t, 6H, N-CH3). 31P{1H}-NMR
(CDCl3): l 61.9 (s, 2P).
2.6. Preparation of
[ReBr(CO)3{Ph2PN(CH3)CH2CH2(CH3)NPPh2}] (5)
A solution of 1 (0.031 g, 0.06 mmol) in CH2Cl2 (7 ml)
was added dropwise with stirring to a solution of
[ReBr(CO)3(NCMe)2] (0.029 g, 0.06 mmol) also in
CH2Cl2 (7 ml) at r.t. The reaction mixture was allowed
to stir for 1 h. The solution was then concentrated to 5
ml under reduced pressure and diluted with 3 ml of
hexane and cooled to 0°C to give crystalline product.
Yield 86%, m.p. 190–191°C (decomposes). Anal.
Found: C, 46.1; H, 3.7; N, 3.4. Calc. for
C31H30BrN2O3P2Re: C, 46.2; H, 3.7; N, 3.5%. IR (KBr,
cm−1): w(CO) 1913(vs), 1953(vs), 2032(vs). 1H-NMR
(CDCl3): l 7.26 (m, 20H, phenyl), 3.48 (dd, 4H,
CH2CH2), 2.48 (t, 6H, N-CH3). 31P{1H}-NMR
(CDCl3): l 91.6 (s, 2P).
2.7. Preparation of [MCl2{Ph2PN(CH3)CH2CH2-
(CH3)NPPh2}] [6, M=Pd; 7, Pt]
2.4. Preparation of [M(CO)4{Ph2PN(CH3)CH2CH2-
(CH3)NPPh2}] (2, M=Cr; 3, M=Mo)
A mixture of 1 (0.08 mmol) and [MCl2(COD)] (M=
Pd or Pt) (0.08 mmol) is stirred in CH2Cl2 (10 ml) at
25°C for 6 h. The reaction mixture is then concentrated
A mixture of 1 (0.117 mmol) and [M(CO)4(NBD)]
(M=Cr or Mo) (0.115 mmol) was heated under reflux