Complexes of ruthenium(II) with unsymmetrical diphosphines and diphosphinomethanides. A way to synthesize chiral metallodiphosphines

Article abstract of DOI:10.1021/om000097y

Ruthenium(II) complexes with the unsymmetrical diphosphinomethanide [PPh₂CHP^tBu₂]^- containing isocyanides and chiral amines as ancillary ligands were prepared, and the molecular structure of [Ru(CN^tBu)₄{PPh₂CHP^tBu₂}] ⁺ was studied by X-ray crystallography. The reactivity of the coordinated methanide toward [AuCl(PPh₃)] was investigated, leading to the stereoselective formation of the chiral metallodiphosphine [PPh₂CH(AuPPh₃)P^tBu₂].

Full text of DOI:10.1021/om000097y

Organometallics 2000, 19, 5533-5536
5533
Com p lexes of Ru th en iu m (II) w ith Un sym m etr ica l
Dip h osp h in es a n d Dip h osp h in om eth a n id es. A Wa y to
Syn th esize Ch ir a l Meta llod ip h osp h in es
Marta E. G. Mosquera, J avier Ruiz,* and V´ıctor Riera
Departamento de Quı´mica Orga´nica e Inorga´nica, Universidad de Oviedo,
33071 Oviedo, Spain
Santiago Garcia-Granda and Miguel A. Salvado´
Departamento de Quı´mica Fı´sica y Analı´tica, Universidad de Oviedo, 33071 Oviedo, Spain
Received February 3, 2000
Summary: Ruthenium(II) complexes with the unsym-
metrical diphosphinomethanide [PPh2CHPtBu2]- con-
taining isocyanides and chiral amines as ancillary
ligands were prepared, and the molecular structure of
[Ru(CNtBu)4{PPh2CHPtBu2}]+ was studied by X-ray
crystallography. The reactivity of the coordinated meth-
anide toward [AuCl(PPh3)] was investigated, leading to
the stereoselective formation of the chiral metallodiphos-
phine [PPh2CH(AuPPh3)PtBu2].
dinated to Ru(II). In this ligand the central carbon is a
prochiral center, so its transformations by electrophilic
attacks could lead to the formation of new chiral
diphosphines or metallodiphosphines. The presence of
a chiral auxiliary ligand coordinated to the metal would
make these attacks stereoselective.
Here we report the synthesis of several Ru(II) deriva-
tives with the unsymmetrical diphosphine [PPh2CH2P-
tBu2], containing isocyanides and chiral amines as
ancillary ligands, and their corresponding derivatives
with the diphosphinomethanide ligand [PPh2CHPtBu2]-.
Some promising results on the reactivity of this ligand
toward electrophiles, which has led to the stereoselective
formation of chiral metallodiphosphines, are also pre-
sented.
In tr od u ction
Complexes of ruthenium(II) with diphosphines are of
interest due to their potential applications in catalytic
processes.1 Those bearing chiral diphosphines are par-
ticularly efficient catalysts for asymmetric hydrogena-
tion of olefinic substrates and have found applications
in the fine chemicals industry.2,3 The central work
within our group has been focused on the transforma-
tion of the diphosphine dppm coordinated to group 7 and
8 metals into new functionalized diphosphines and
metallodiphosphines.4 These transformations are ac-
complished via electrophilic attack on the corresponding
intermediate complexes containing the coordinated
methanide ligand [PPh2CHPPh2]-. We considered in-
teresting the extension of these studies to the unsym-
metrical diphosphinomethanide [PPh2CHPtBu2]- coor-
Resu lts a n d Discu ssion
When the diphosphine {PPh2CH2PtBu2}5 was refluxed
with trans-[Ru(Cl)2(CNtBu)4]6 in toluene for 4 h, a
mixture of three compounds was formed. These com-
pounds were identified in the 31P{1H} NMR and IR
spectra of the reaction mixture as cis,trans-[Ru(Cl)2(CN-
tBu)2{PPh2CH2PtBu2}] (1a ) and two isomers of mer-[Ru-
(Cl)(CNtBu)3{PPh2CH2PtBu2}]Cl (1b,c) (Scheme 1). The
chemical shift values in the phosphorus NMR spectra
allowed us to distinguish the different species formed,
since the presence of a chloride or an isocyanide ligand
trans to the phosphine promotes opposite displacement
of the chemical shift in comparison with the uncoordi-
nated ligand, as observed in related dppm-isocyanide
complexes.7 Derivatives 1a -c follow this behavior,
showing the chemical shift of the phosphorus trans to
a chloride moved more than 30 ppm toward low field
(in relation to the free phosphine), whereas in the case
of the isocyanide the shift is only about 5 ppm toward
high field (see Table 1). A careful choice of the reaction
conditions allowed the selective synthesis of the deriva-
tive mer-[Ru(Cl)(CNtBu)3{PPh2CH2PtBu2}](Cl) (1c),
where the Cl ligand is trans to the PtBu2 group.
(1) (a) McAulife, C. A. In Comprehensive Coordination Chemistry;
Wilkinson, G., Gillard, R. D., McCleverty, J ., Eds.; Pergamon: Oxford,
1987; Vol. 2, p 989. (b) Schroder, M.; Stephenson, T. A. In Compre-
hensive Coordination Chemistry; Wilkinson, G., Gillard, R. D., Mc-
Cleverty, J ., Eds.; Pergamon: Oxford, 1987; Vol. 4, p 366.
(2) (a) Parshall, G. W.; Ittel, S. D. Homogeneous Catalysis; J ohn
Wiley: New York, 1992; pp 36-39. (b) Takaya, H.; Ohta, T.; Mashima,
K. In Homogeneous Transition Metal Catalyzed Reactions; Moser, W.
R., Slocum, D. W., Eds.; Advances in Chemistry Series 230; ACS:
Washington, 1992; pp 123-142.
(3) (a) Noyori, R.; Takaya, H. Acc. Chem. Res. 1990, 23, 345. (b)
Noyori, R. Chem. Soc. Rev. 1989, 18, 187. (c) Noyori, R. Tetrahedron
1994, 50, 4259. (d) Ojima, I.; Clos, N.; Bastos, C. Tetrahedron 1989,
45, 6901. (e) Znetti, N. C.; Spindler, F.; Spencer, J .; Togni, A.; Grety,
R. Organometallics 1996, 15, 860. (f) Wiles, J . A.; Lee, C. E.; McDonald,
R.; Bergens, S. H. Organometallics 1996, 15, 3782. (g) Mikami, K.;
Korenaga, T.; Terada, M.; Ohkuma, T.; Pham, T.; Noyori, R. Angew.
Chem., Int. Ed. 1999, 38, 495.
(4) (a) Ruiz, J .; Riera, V.; Vivanco, M.; Lafranchi, M.; Tiripicchio,
A. Organometallics 1998, 17, 3835. (b) Ruiz, J .; Mosquera, M. E. G.;
Riera, V.; Vivanco, M.; Bois, C. Organometallics 1997, 16, 3388. (c)
Ruiz, J .; Riera, V.; Vivanco, M.; Garcia-Granda, S. Organometallics
1996, 15, 1080. (d) Ruiz, J .; Riera, V.; Vivanco, M.; Lafranchi, M.;
Tiripicchio, A. Organometallics 1996, 15, 1082. (e) Ruiz, J .; Arauz, R.;
Riera, V.; Vivanco, M.; Garc´ıa-Granda, S.; Perez-Carren˜o, A. J . Chem.
Soc., Chem. Commun. 1993, 740.
(5) Grim, S. O.; Smith, P. H.; Colquhoun, I. J .; MacFarlane, W. Inorg.
Chem. 1980, 19, 3195.
(6) Bassett, J . M.; Berry, D. E.; Barker, G. K.; Green, M.; Howard,
J . A. K.; Stone, F. G. A. J . Chem. Soc., Dalton Trans. 1979, 1003.
(7) (a) Ruiz, J .; Riera, V.; Vivanco, M. J . Chem. Soc., Dalton Trans.
1995, 1069. (b) Mosquera, M. E. G.; Ruiz, J .; Riera, V. J . Organomet.
Chem. 1997, 527, 35.
10.1021/om000097y CCC: $19.00 © 2000 American Chemical Society
Publication on Web 11/15/2000

5534 Organometallics, Vol. 19, No. 25, 2000
Notes
Sch em e 1
Ta ble 1. IR a n d 31P {1H} NMR Da ta for Com p ou n d s
1-4 a n d {P P h 2CH2P tBu 2}
Sch em e 2a
31P{1H} NMR, (δ, ppm; J , Hz)b
compound
ν(CN),a cm-1
δ (PtBu2)
δ (PPh2)
2J PP
{PPh2CH2PtBu2}
15.8 (d)
52.1 (d)
11.7 (d)
48.7 (d)
58.6 (d)
22.5 (d)
42.9 (d)
43.9 (d)
21.5 (d)
35.9 (d)
-15.0 (d)
20.4 (d)
17.0 (d)
-22.7 (d)
-15.4 (d)
-15.3 (d)
-16.7 (d)
-16.2 (d)
-29.7 (d)
-25.4 (d)
138
41
37
1a
1b
1c
2
3a
3b
3c
4a
4b
2201 (w), 2164 (s)
2210 (w), 2175 (s)
2216 (w), 2174 (s)
2194 (w), 2156(s)
2196 (w), 2159(s)
2202 (w), 2153(s)
2186 (w), 2148(s)d
43
46c
39c
36c
37c
9c
8e
a
b
In CH2Cl2. Abbreviations: w ) weak, s ) strong. In CH2Cl2
with D2O capillary. Abbreviation: d ) doublet. c In CD2Cl2. In
d
THF. e In THF with D2O capillary.
In the next step of our work, we changed the chloride
ligand in 1c for a neutral ligand. We were particularly
interested in coordinating a chiral group that could act
as a chirality inductor in further reactions on the
diphosphine. Therefore 1c was first treated with AgClO4
to give mer-[Ru(OClO3)(CNtBu)3{PPh2CH2PtBu2}]+ (2);
second, 2 was reacted with an excess of the correspond-
ing neutral ligand L, affording mer-[Ru(L)(CNtBu)3-
a
3a ,4a , L ) CNtBu; 3b,4b,5b, L ) CyCH(Me)NH2; 3c,5c,
t
{PPh2CH2PtBu2}](ClO4)2 (3a , L ) BuCN; 3b, L ) (S)-
L ) PhCH(Me)NH2; P ) PPh2, P′ ) PtBu2.
CyCH(Me)NH2; 3c, L ) (S)-PhCH(Me)NH2). These new
compounds were fully spectroscopically characterized
(see Experimental Section). It is worth remarking that
the presence of a chiral ligand in 3b,c promotes a
differentiating factor in the equatorial plane of the
molecule. Thus the axial isocyanide groups that are
equivalents in the achiral derivatives (2 and 3a ) become
diastereotopic in 3b,c. This inequivalence is evidenced
in the proton spectra by the presence of three different
tion into a quaternary atom would lead to the formation
of chiral diphosphines or metallodiphosphines.
Only in the case of 4a could suitable crystals for an
X-ray structural determination be grown. The molecular
structure of 4a (Figure 1) shows the coordinated un-
symmetrical ligand {PPh2CHPtBu2}- with a coplanar
Ru-P(1)-P(2)-C(9) skeleton. The P(1)-C(9) (1.723 (10)
Å) and P(2)-C(9) (1.724 (10) Å) distances are very
similar and fall between the usual values observed for
single and double bonds, suggesting that the excess of
electronic density on the carbon atom is equally shared
by both phosphorus atoms. The Ru(1)-P(1) distance
(2.369(3) Å) is similar to that observed in other diphos-
phino methanide complexes (2.35 Å on average).4b
However the Ru(1)-P(2) bond length appears a bit
longer, 2.464(4) Å, perhaps owing to the greater steric
congestion around the donor atom in the P(2)R3 group,
as suggested in other ruthenium complexes with phos-
phines.9
Finally we studied the reactivity of the coordinated
ligand {PPh2CHPtBu2}- toward electrophiles, starting
with the species [AuCl(PPh3)] since its behavior with
other methanide complexes is well established.4b The
reaction was generally carried out in a one-pot process
by stirring a mixture of mer-[Ru(L)(CNtBu)3{PPh2-
CH2PtBu2}](ClO4)2 (3b ,c), KOH, and AuClPPh3. This
t
signals for the CNtBu groups. Equally, the Bu groups
in the diphosphine are diastereotopic, appearing as two
3
doublets with similar J PH values (in the achiral com-
pounds the PtBu2 groups appear as a unique doublet).
The deprotonation reaction of mer-[Ru(L)(CNtBu)3-
{PPh2CH2PtBu2}]2+ (3a ,b) with KOH in CH2Cl2 or THF
led to the formation of the new diphosphinomethanide
species [Ru(L)(CNtBu)3{PPh2CHPtBu2}]+ (4a , L
)
tBuCN; 4b, L ) (S)-CyCH(Me)NH2) (Scheme 2). Al-
though a large number of diphosphinomethanides con-
taining two equivalent phosphino groups are known,8
compounds 4a ,b are, to our knowledge, the first ex-
amples where the coordinated diphosphinomethanide
is unsymmetrical. This feature converts the central
carbon atom in a prochiral center; hence its transforma-
(8) (a) Puddhepatt, R. J . Chem. Soc. Rev. 1983, 12, 99. (b) Karsch,
H. H.; Richter, R.; Deubelly, B.; Schier, A.; Paul, M.; Heckel, M.;
Angermeir, K.; Hiller, W. Z. Naturforsch. B: Chem. Sci. 1994, 49, 1798.
(c) Balch, A. L.; Oram, D. E. Organometallics 1986, 5, 2159. (d) Karsch,
H. H.; Ferazin, G.; Kooijman, H.; Steigelmann, O.; Hiller, W. Angew.
Chem., Int. Ed. Engl. 1993, 32, 1739. (e) Kasani, A.; McDonald, R.;
Cavell R. G., Organometallics 1999, 18, 3775.
(9) Campion, B. K.; Heyn, R. H.; Tilley, T. D. J . Chem. Soc., Chem
Commun, 1988, 278.

Notes
Organometallics, Vol. 19, No. 25, 2000 5535
electrophilic attack of CH3X on the compounds [Rh(η5-
C9H7)(chiral diphosphine)] on changing the diphosphine
from PPh2CH2CH(Ph)PPh2 (phenphos) to PPh2CH2CH-
(Cy)PPh2 (cyphos).11
In conclusion we have prepared in this work some
ruthenium(II) complexes with the unsymmetrical diphos-
phine {PPh2CH2PtBu2} and the corresponding diphos-
phinomethanide {PPh2CHPtBu2}-, containing chiral
amines as ancillary ligands. From these, the new chiral
metallodiphosphine {PPh2CH(AuPPh3)PtBu2} coordi-
nated to ruthenium(II) can be synthesized in moderate
diastereomeric excess. Unfortunately, the extension of
this reactivity to organic electrophiles, such as RX,
RCtC-X, or RC(O)X (R ) alkyl or aryl, X ) halogen)
has not been successful so far, precluding practical
application in enantioselective synthesis of chiral diphos-
phines. Nonetheless, this study establishes the potential
of unsymmetrical diphosphinomethanides, coordinated
to transition metal complexes with chiral ancillary
ligands, for the diastereoselective transformation of
coordinated diphosphines.
F igu r e 1. Molecular structure of the cationic complex in
4a together with the atomic numbering system. Selected
Bond lengths (Å) and Angles (deg): Ru-P(1) 2.369(3),
Ru-P(2) 2.464(4), P(2)-C(9) 1.724(10), P(1)-C(9)
1.723(10), Ru-C(4) 2.000(10), Ru-C(3) 1.982(11), Ru-C(2)
1.995(11), Ru-C(1) 2.019(12), P(1)-C(9)-P(2) 102.4(4),
P(1)-Ru-P(2) 67.5(2).
Exp er im en ta l Section
Gen er a l Con sid er a tion s. For the general experimental
procedure see ref 4b. The compounds {PPh2CH2PtBu2}5 and
[Ru(Cl)2(CNtBu)4]6 were prepared as described elsewhere.
m er -[(Ru (Cl)(CNtBu )3{P P h 2CH2P tBu 2}]Cl (1c). A solu-
tion in 7 mL of toluene of trans-[Ru(Cl)2(CNtBu)4] (0.15 g, 0.29
mmol) and the diphosphine {PPh2CH2PtBu2} (0.15 g, 0.43
mmol) was refluxed for 3 h. In the reaction mixture white
crystals appeared corresponding to 1c. These crystals were
washed with ether three times to eliminate the excess of
diphosphine and other minor products and dried in the vacuum
Ta ble 2. Selected Sp ectr oscop ic Da ta for
Com p lexes 5
31P{1H} NMR, (δ,ppm; J ,Hz)b
ν(CN),a
δ
δ
δ
3
compound
(SS/SR)5b
cm-1
(PtBu2)
(AuP)
(PPh2) 2J PP J PP
2189 (w),
2149 (s)
(86%)
major
diastereomer
minor
diastereomer
63.0 (dd) 42.4 (t) 1.2 (dd) 40
63.1 (dd) 42.7 (t) 1.4 (dd) 39
7
6
line. Yield: 0.19 g (85%). Anal. Calcd for RuCl2P2N3C36H57
:
C, 56.46; H, 7.50; N, 5.49. Found: C, 55.96; H, 7.33; N, 5.03.
(14%)
2
1H NMR (CD2Cl2): δ 8.13-7.41 (10H, Ph); 4.14 (t, 2H, J HP
)
10, CH2); 1.54 (s, 9H, CNtBu); 1.29 (s, 18H, CNtBu); 1.25 (d,
(SS/SR)5c
2190 (w),
2151 (s)
(82%)
18H, J PH ) 15, PtBu2). 13C NMR (CD2Cl2): δ 147.2 (br, CNt-
3
major
diastereomer
63.9 (dd) 42.3 (t) 1.2 (dd) 33
63.4 (dd) 42.8 (t) 2.4 (dd) 31
7
7
Bu); 135.3-126.2 (Ph); 58.5 (s, CNC(CH3)3); 58.3 (s, CNC(CH3)3);
1
1
1
37.6 (d, J PC ) 13, PC(CH3)3); 36.6 (dd, J PC ) 26, J PC ) 17,
P2CH2); 31.1 (s, CNC(CH3)3); 30.2 (d, 2J PC ) 3, PC(CH3)3); 30.1
(s, CNC(CH3)3).
minor
diastereomer
(18%)
a
b
In CH2Cl2. In CH2Cl2 with D2O capillary.
m er -[Ru (OClO3)(CNtBu )3{P P h 2CH2P tBu 2}](ClO4) (2). A
76 mg (0.1 mmol) sample of the compound mer-[Ru(Cl)(CN-
tBu)3{PPh2CH2PtBu2}](Cl) was reacted with 40 mg (0.2 mmol)
of AgClO4 in 10 mL of CH2Cl2. After being stirring for 1 h, the
solution was filtered and the filtrate reduced under vacuum.
The white solid obtained was washed with hexane and dried
under vacuum. Yield: 79 mg (89%). Anal. Calcd for RuO8-
Cl2P2N3C36H57: C, 48.38; H, 6.43; N, 4.90. Found: C, 47.85;
H, 6.67; N, 4.24. 1H NMR (CD2Cl2): δ 7.89-7.43 (10H, Ph);
4.02 (t, 2H, 2J HP ) 10, CH2); 1.57 (s, 9H, CNtBu); 1.34 (s, 18H,
CNtBu); 1.26 (d, 18H, 3J PH ) 15, PtBu2). 13C NMR (CD2Cl2): δ
144.1 (br, CNtBu); 134.1-129.3 (Ph); 59.4 (s, CNC(CH3)3); 59.1
methodology allowed us to obtain the complexes mer-
[Ru(L)(CNtBu)3{PPh2CH(AuPPh3)PtBu2}]2+ (5b, L )
(S)-CyCH(Me)NH2; 5c, L ) (S)-PhCH(Me)NH2) (Scheme
2), which contain a new chiral metallodiphosphine. As
expected, the reaction was diastereoselective due to the
presence of the chiral amine. In the 31P{1H} NMR
spectra of 5b and 5c it is possible to clearly distinguish
the signals due to each diastereomer with a major
isomer observed in both cases, as summarized in Table
2.
It was not possible to resolve the diasteromeric
mixture in 5b and 5c compounds, preventing the
determination of the absolute configuration of the major
and minor isomer. The de was estimated from the value
of the NMR band integrals,10 being 72 for 5b and 64 in
5c. The slightly better ability as a chirality inductor of
the cyclohexylamine can be attributed to the major
steric hindrance promoted by the cyclohexyl ring in
relation to the phenyl ring. In this context, Morandini
observed an increase of the diastereoslectivity in the
1
3
(s, CNC(CH3)3); 37.8 (dd, J PC ) 15, J PC ) 3, PC(CH3)3); 35.3
1
1
(dd, J PC ) 26, J PC ) 17, P2CH2); 30.6 (s, CNC(CH3)3); 29.9
2
(d, J PC ) 3, PC(CH3)3); 29.7 (s, CNC(CH3)3).
Syn th esis of Com p ou n d s [Ru (L)(CNtBu )3{P P h 2CH2P -
tBu 2}](ClO4)2 (3). In a general procedure, compound 2 (0.1 g,
0.11 mmol) was dissolved in 10 mL of CH2Cl2, and to this
solution 0.04 mL (0.33 mmol) of tBuNC was added. The
mixture was stirred for 10 h at room temperature. The solvent
was reduced under vacuum, and a white solid corresponding
to 3a precipitated by the addition of 20 mL of hexane. The
solid was washed with hexane and dried in a vacuum. Yield:
(10) (a) Staubach, B.; Buddrus, J . Angew. Chem., Int. Ed. Engl. 1996,
35, 1344. (b) Nelson, J . H. Coord. Chem. Rev. 1995, 139, 245.
(11) Morandini, F.; Pilloni, G.; Consiglio, G.; Sironi, A.; Moret, M.
Organometallics 1993, 12, 3495.

5536 Organometallics, Vol. 19, No. 25, 2000
Notes
100 mg (93%). Anal. Calcd for RuO8Cl2P2N4C41H66: C, 50.41;
P h (5c)). To a solution of the derivative 3b or 3c (75 mg, 0.07
mmol) in 10 mL of CH2Cl2 were added 35 mg (0.07 mmol) of
AuCl(PPh3) and 1.25 g of KOH. The reaction mixture was
stirred for 10 min and then filtered. A 20 mL sample of ether
was added to the filtrate, and a white solid was formed. This
solid constitutes a mixture of the SR and SS isomers of 5.
(SS/SR)5b. Yield: 95 mg (64%). Anal. Calcd for RuAuO8-
Cl2P3N4C62H88: C, 50.34; H, 6.00; N, 3.79. Found: C, 50.03;
H, 5.93; N, 3.74; de 72. 1H NMR (major isomer) (CD2Cl2): δ
8.38-7.05 (25H, Ph); 3.63 (td, H, 2J HP ) 13, 3J HP ) 10, P2CH);
3.84 (m, H, CH); 2.58 (m, H, CHNH2); 1.67 (s, 9H, CNtBu);
1.58 (s, 9H, CNtBu); 1.32 (s, 2H, NH2); 1.19 (s, 9H, CNtBu);
1
H, 6.81; N, 5.73. Found: C, 49.93; H, 6.77; N, 5.57. H NMR
(CD2Cl2): δ 7.81-7.39 (10H, Ph); 4.28 (dd, 2H, 2J HP ) 11, 2J HP
) 9, CH2); 1.68 (s, 9H, CNtBu); 1.59 (s, 9H, CNtBu); 1.33 (s,
3
18H, CNtBu); 1.31 (d, 18H, J PH ) 15, PtBu2). 13C NMR (CD2-
Cl2): δ 148.3 (br, CNtBu); 132.9-129.1 (Ph); 60.8 (s, CNC(CH3)3);
1
3
60.2 (s, CNC(CH3)3); 37.3 (dd, J PC ) 12, J PC ) 4, PC(CH3)3);
1
1
34.6 (dd, J PC ) 29, J PC ) 18, P2CH2); 30.7 (s, C(CH3)3); 30.6
(s, C(CH3)3); 29.8 (s, C(CH3)3).
mer -[Ru {S-CH3CH(C6H11)NH2}(CNtBu )3{P P h 2CH2P tBu 2}]-
(ClO4)2 (3b) was obtained from 2 (0.1 g, 0.11 mmol) and S-CH3-
CH(C6H11)NH2 (17 µL, 0.12 mmol) as a white solid. Yield: 103
mg (92%). Anal. Calcd for RuO8Cl2P2N4C44H74: C, 51.76; H,
3
3
1.46 (d, 9H, PtBu2, J PH ) 14); 1.33 (d, 9H, PtBu2, J PH ) 12);
2.38-0.84 (CH2 and CH3). 13C NMR (major isomer) (CD2Cl2):
δ 134.4-128.9 (Ph); 62.3 (s, C(H)NH2); 61.2 (s, CNC(CH3)3);
59.7 (s, CNC(CH3)3); 59.3 (s, CNC(CH3)3); 45.1 (s, CH, Cy); 38.0
7.30; N, 5.49. Found: C, 51.51; H, 7.31; N, 5.60. [R]20 -1.1°
D
(c ) 0.002 gr/mL; CH2Cl2). 1H NMR (CD2Cl2): δ 7.94-7.38
2
(10H, Ph); 4.03 (t, 2H, J HP ) 10, P2CH2); 3.67 (m, H, CH);
2.89 (m, H, CHNH2); 1.57 (s, 9H, CNtBu); 1.53 (s, 9H, CNtBu);
1.32 (s, 2H, NH2); 1.27 (s, 9H, CNtBu); 1.38 (d, 9H, PtBu2, 3J PH
) 15); 1.23 (d, 9H, PtBu2, 3J PH ) 15); 2.38-0.84 (CH2 and CH3).
13C NMR (CD2Cl2): δ 134-128 (Ph); 62.3 (s, C(H)NH2); 60.5
(s, CNC(CH3)3); 60.4 (s, CNC(CH3)3); 59.8 (s, CNC(CH3)3); 44.1
(m, PC(CH3)3); 36.6 (d, PC(CH3)3, J PC ) 16); 51.6 (dd, J PC )
1
1
19, 1J PC ) 10, P2CH); 31.1-26.2 (CH2 and CH3); 17.7 (s, MeC-
(H)NH2).
(SS/SR)5c. Yield: 69 mg (67%). Anal. Calcd for RuAuO8-
Cl2P3N4C62H82: C, 50.55; H, 5.61; N, 3.80. Found: C, 50.30;
H, 5.53; N, 3.74; de 64. 1H NMR (major isomer) (CD2Cl2): δ
8.36-7.08 (30H, Ph); 4.04 (m, CH); 3.62 (td, H, 2J HP ) 13, 3J HP
) 11, P2CH); 1.67 (s, 9H, CNtBu); 1.57 (s, 9H, CNtBu); 1.17 (s,
1
3
(s, CH, Cy); 37.8 (dd, J PC ) 14, J PC ) 6, PC(CH3)3); 37.0 (d,
PC(CH3)3, J PC ) 15); 35.5 (dd, J PC ) 28, J PC ) 16, P2CH2);
31.2, 29.1, 26.6, 26.3, 26.2 (CH2, Cy); 30.7 (s, CNC(CH3)3); 30.1
(s, CNC(CH3)3); 30.0 (s, CNC(CH3)3); 30.4 (d, J PC ) 3, PC-
(CH3)3); 29.9 (d, J PC ) 3, PC(CH3)3); 17.8 (s, MeC(H)NH2).
1
1
1
2
3
9H, CNtBu); 1.30 (s, 2H, NH2); 1.44 (d, 9H, J PH ) 14, PtBu2);
2
1.31 (d, 9H, 3J PH ) 11, PtBu2). In a similar way it was possible
to prepare the mixture of the RS and RR isomers, using as
starting materials the corresponding R enantiomers of 3b and
3c, whose spectroscopic data are identical to the SR/ SS
mixture.
Obviously, by using (R)-CH3CH(C6H11)NH2 it was possible to
prepare the R enantiomer, whose spectroscopic data are identi-
cal to 3b.
m er -[Ru {S-CH3CH(P h )NH2}(CNtBu )3{P P h 2CH2P tBu 2}]-
(ClO4)2 (3c) was obtained from 2 (0.1 g, 0.11 mmol) and (S)-
CH3CH(C6H5)NH2 (15 µL, 0.12 mmol) as a white solid. Yield:
102 mg (91%). Anal. Calcd for RuO8Cl2P2N4C44H68: C, 52.07;
X-r a y Cr ysta llogr a p h y. Crystal data for 4a : [C41H65
-
RuN4P2][ClO4]‚CH2Cl2, Mr ) 961.36, orthorhombic, space
group P212121, a ) 12.76(1) Å, b ) 16.30(2) Å, c ) 24.71(9) Å,
V ) 5140(20) Å3, Z ) 4, Fcalc ) 1.24 Mg m-3, F(000) ) 2016,
λ(Mo KR) ) 0.71073 Å, µ ) 5.62 cm-1, T ) 200 K; yellow
crystals (0.30 × 0.26 × 0.23 mm); Nonius CAD4 diffractometer;
ω-2θ scan technique; 3984 reflections measured (0° < θ <
23°), all used in refinement. The structure was solved by direct
methods and refined by full-matrix least-squares on F2 pro-
cedures: R ) 0.050 (for 3044 I > 2σ(I)), and wR2 ) 0.134 (for
all reflections), w ) 1.0/[σ2(Fo)2 + (0.071P)2 + 3.8P] where P
) (max(Fo2,0) + 2Fc2)/3; total number of parameters 507;
residual electron density less than 0.70 e Å-3. Absolute
configuration was checked (Flack parameter c ) 0.00(7)). The
plot in Figure 1 was made by the EUCLID package.12 Ad-
ditional crystallographic data are available in the Supporting
Information.
H, 6.75; N, 5.52. Found: C, 51.99; H, 6.82; N, 5.16. [R]20
D
1
-21.8° (c ) 0.01 gr/mL; CH2Cl2). H NMR (CD2Cl2): δ 7.90-
7.19 (15H, Ph); 4.74 (m, CH); 4.01 (m, 2H, P2CH2); 1.61 (s,
9H, CNtBu); 1.56 (s, 9H, CNtBu); 1.04 (s, 9H, CNtBu); 1.39 (d,
3
3
9H, J PH ) 15, PtBu2); 1.23 (d, 9H, J PH ) 15, PtBu2); 1.27 (s,
NH2). Using (R)-CH3CH(C6H5)NH2 it is possible to prepare the
R enantiomer, whose spectroscopic data are identical to 3c.
[Ru (CNtBu )4{P P h 2CHP tBu 2}](ClO4) (4a ). To a solution
of 3a (80 mg, 0.08 mmol) in 10 mL of CH2Cl2 was added 1.25
g of KOH. The reaction mixture was stirred for 1 h. The
solution was then filtered and 20 mL of ether carefully added
to the filtrate. Slow diffusion of the solvents afforded crystals
of 4a . Yield: 43 mg (60%). Anal. Calcd for RuO4ClP2N4C41
-
H
65: C, 56.19; H, 7.47; N, 6.39. Found: C, 56.35; H, 7.22; N,
6.01. 1H NMR (CD2Cl2): δ 7.74-7.21 (10H, Ph); 1.86 (t, H,
2J PH ) 3, CH); 1.67 (s, 9H, CNtBu); 1.51 (s, 9H, CNtBu); 1.22
(d, 18H, 3J PH ) 14, PtBu2); 1.15 (s, 18H, CNtBu). 13C NMR (CD2-
Ack n ow led gm en t. We gratefully acknowledge the
Ministerio de Educacio´n y Ciencia for financial as-
sistance (Project DGE-96-PB-0317) and for a research
grant (M.E.G.M.).
Cl2): δ 145.2 (br, CNtBu); 143.7 (d, CNtBu, J CP ) 5); 143.1
2
(br, C, CNtBu); 58.6 (s, CNC(CH3)3); 58.2 (s, CNC(CH3)3); 57.7
1
3
(s, CNC(CH3)3); 38.4 (dd, J PC ) 16, J PC ) 5, PC(CH3)3); 31.1
(s, C(CH3)3); 30.8 (s, C(CH3)3); 30.6 (s, C(CH3)3); 29.9 (s,
Su p p or tin g In for m a tion Ava ila ble: Tables of bond
distances, angles, positional parameters, anisotropic thermal
parameters, and hydrogen atom coordinates of 4a . This
material is available free of charge via the Internet at
http://pubs.acs.org.
1
1
C(CH3)3); 14.2 (dd, J PC ) 66, J PC ) 47, P2CH).
mer -[Ru {S-CH3CH(C6H11)NH2}(CNtBu )3{P P h 2CHP tBu 2}]-
(ClO4) (4b). Following a similar procedure as above, using
THF as a solvent, 4b was isolated as a yellow solid. Yield:
65%. Anal. Calcd for RuO4ClP2N4C44H73: C, 57.41; H, 7.99;
N, 6.09. Found: C, 56.97; H, 7.57; N, 5.98.
OM000097Y
Syn th esis of m er -[Ru {S-(CH3CH(R)NH2}(CNtBu )3-
{P P h 2CH{Au (P P h 3)}P tBu 2}](ClO4)2 (R ) C6H11(5b), R )
(12) Spek, A. L. In Computational Crystallography; Sayre, D., Ed.;
Clarendon Press: Oxford, U.K., 1982; p 528.