Reactivity of bis(diphenylphosphino)methanide complexes of manganese(I) toward halogens and Pseudohalogens

Article abstract of DOI:10.1021/om980391e

C-Functionalized diphosphinomethanide and diphosphine ligands of formula [(PPh₂)₂CX]^- and [(PPh₂)₂C(X)(Y)] (X = I, CN, SCN, SePh, Y = H; X = Br, Y = H, Br), coordinated to manganese(I), have been prepared by reaction of the methanide complexes [Mn(L)(CO)₃-{(PPh₂)₂CH}] (L = CO, CN^tBu) with the halogen and pseudohalogen molecules Br₂, I₂, BrCN, (CN)₂, (SCN)₂ and ISePh followed, when necessary, by the appropriate basic (KOH) or acidic (HBF₄) treatment.

Full text of DOI:10.1021/om980391e

4562
Organometallics 1998, 17, 4562-4567
Rea ctivity of Bis(d ip h en ylp h osp h in o)m eth a n id e
Com p lexes of Ma n ga n ese(I) tow a r d Ha logen s a n d
P seu d oh a logen s
J avier Ruiz, V´ıctor Riera,* and Maril´ın Vivanco
Departamento de Quı´mica Orga´nica e Inorga´nica, Instituto de Quı´mica Organometa´lica,
Universidad de Oviedo, 33071 Oviedo, Spain
Santiago Garc´ıa-Granda and M. R. D´ıaz
Departamento de Quı´mica Fı´sica y Analı´tica, Universidad de Oviedo, 33071 Oviedo, Spain
Received May 18, 1998
C-Functionalized diphosphinomethanide and diphosphine ligands of formula [(PPh2)2CX]-
and [(PPh2)2C(X)(Y)] (X ) I, CN, SCN, SePh, Y ) H; X ) Br, Y ) H, Br), coordinated to
manganese(I), have been prepared by reaction of the methanide complexes [Mn(L)(CO)3-
{(PPh2)2CH}] (L ) CO, CNtBu) with the halogen and pseudohalogen molecules Br2, I2, BrCN,
(CN)2, (SCN)2 and ISePh followed, when necessary, by the appropriate basic (KOH) or acidic
(HBF4) treatment.
In tr od u ction
formation of new C-halogenated diphosphines derived
from dppm, as a result of the chemoselective halogena-
tion at the central carbon atom. We have also extended
the study of the reactivity of coordinated diphosphi-
nomethanides to pseudohalogen molecules such as
BrCN, (CN)2, (SCN)2, and ISePh, which has led to the
formation of the new functionalized diphosphino-
methanide ligands [(Ph2P)2CCN]-, [(Ph2P)2CSCN]-, and
[(Ph2P)2CSePh]- and their corresponding diphosphines
(Ph2P)2C(H)CN, (Ph2P)2C(H)SCN, and (Ph2P)2C(H)-
SePh. Preliminary accounts of some of this work have
been published.6,7
A rich chemistry has been developed around the
reactivity of alkali-metal diphosphinomethanides with
halides of many metallic and nonmetallic elements
(MXn).1 This has led to the preparation of a number of
diphosphinomethanide derivatives displaying remark-
able features, such as a variety of coordination modes
(mono-, bi-, and tridentate through the carbon and
phosphorus donor atoms), high coordination numbers,2
and the noteworthy stabilization of molecules with
elements in low oxidation states, such as those of silicon-
(II).3 However, as far as we know, the study of the
reactivity of diphosphinomethanide anions with dihalo-
gen molecules themselves (X2) has been limited to the
treatment of lithium bis(diphenylphosphino)methanide
with iodine, leading to the formation of PPh2PCHdPPh2-
PPh2dCHPPh2, (Ph2P)2CdPPh2CH2PPh2, and (Ph2P)2-
CHCH(PPh2)2, which result from P-P, P-C, and C-C
coupling, respectively.4,5 Curiously, no halogenation
product was isolated from the above reaction. In
relation to this, as we will describe throughout this
paper, we have found that the reaction of bis(diphen-
ylphosphino)methanide η2(P,P′)-coordinated in manga-
nese(I) carbonyl complexes toward dihalogens (Br2 and
I2) takes place in a very different way, allowing the
Resu lts a n d Discu ssion
Rea ction s of [Mn (CO)4{(P h 2P )2CH}] (2a ) a n d fa c-
[Mn (CNtBu )(CO)3{(P h 2P )2CH}] (2b) w ith Dih a lo-
gen s. The diphosphinomethanide derivatives 2a ,b,
which were prepared from the corresponding cationic
dppm complexes [Mn(L)(CO)3{(Ph2P)2CH2}]ClO4 (1a , L
) CO; 1b, L ) CNtBu) by treatment with KOH,8 readily
react with Br2 or I2 in CH2Cl2 to give [Mn(L)(CO)3-
{(Ph2P)2C(H)X}]X3 (3a , L ) CO, X ) Br; 3b, L ) CNt-
Bu, X ) Br; 3c, L ) CO, X ) I; 3d , L ) CNtBu, X ) I)
(see Scheme 1). These compounds contain the new
C-halogenated diphosphines (PPh2)2C(H)X, arising from
the heterolytic cleavage of the X2 molecules promoted
by the methanide carbon atom. As the ligand [(PPh2)2-
CH]- in 2a ,b is strongly bonded to manganese through
the phosphorus atoms, the halogenation reaction was
chemoselective on the methanide carbon atom and did
not take place to any extent on the phosphorus atoms,
(1) (a) Balch, A. L.; Oram, D. E. Inorg. Chem. 1987, 26, 1906. (b)
Hao, S., Song, J .; Aghabozorg, H.; Gambarotta, S. J . Chem. Soc., Chem.
Commun. 1994, 157. (c) Karsch, H. H.; Grauvogl, G.; Kawecki, M.;
Bissinger, P.; Kumberger, O.; Schier, A.; Mu¨ller, G. Organometallics
1994, 13, 610. (d) Karsch, H. H.; Witt, E. J . Organomet. Chem. 1997,
529, 151 and references therein.
(2) (a) Karsch, H. H.; Ferazin, G.; Steigelmann, O.; Kooijman, H.;
Hiller, W. Angew. Chem., Int. Ed.. Engl. 1993, 32, 1739. (b) Karsch,
H. H.; Deubelly, B.; Keller, U.; Steigelmann, O.; Lachmann, J .; Mu¨ller,
G. Chem. Ber. 1996, 129, 671.
(3) Karsch, H. H.; Keller, U.; Gamper, S.; Mu¨ller, G. Angew. Chem.,
Int. Ed. Engl. 1990, 29, 295.
(4) Braunstein, P.; Hasselbring, R.; Tiripicchio, A.; Ugozzoli, F. J .
Chem. Soc., Chem. Commun. 1995, 37.
(6) Ruiz, J .; Arau´z, R.; Riera, V.; Vivanco, M.; Garc´ıa-Granda, S.;
Mene´ndez-Vela´zquez, A. Organometallics 1994, 13, 4162.
(7) Ruiz, J .; Riera, V.; Vivanco, M.; Garc´ıa-Granda, S.; Salvado´, M.
A. Organometallics 1996, 15, 1079.
(5) Braunstein, P.; Hasselbring, R.; DeCian, A.; Fischer, J . Bull. Soc.
Chim. Fr. 1995, 132, 691.
(8) Ruiz, J .; Riera, V.; Vivanco, M.; Garc´ıa-Granda, S.; Garc´ıa-
Ferna´ndez, A. Organometallics 1992, 11, 4077.
S0276-7333(98)00391-4 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 09/24/1998

Bis(diphenylphosphino)methanide Complexes of Mn(I)
Organometallics, Vol. 17, No. 21, 1998 4563
Sch em e 1
as does occur in free phosphines.9 In contrast with that
found by Braunstein et al. in the treatment of Li-
[(PPh2)2CH] with I2,5 we have not detected in the
present reactions any product of oxidative C-C cou-
pling. These authors have proposed that the formation
of the tetraphosphine (Ph2P)2CHCH(PPh2)2 in the above
reaction takes place through the radical intermediate
[(PPh2)2CH]• rather than through a metal-halogen
exchange. We think, however, that this last pathway
cannot be excluded in view of the formation of [(PPh2)2C-
(H)X] in our synthetic approach.
d , some amount of 1a -d and [Mn(L)(CO)3{(Ph2P)2CX}]
(4a -d ) (see below) due to proton migration from 3 to 2.
The presence of an excess of X2 is the reason in every
-
case the counteranion is the species X3 and not the
monoatomic anion X-, first formed in the heterolytic
cleavage of the X2 molecule by the diphosphinomethanide
ligand.
For 3b,d (L ) CNtBu) two isomers are possible,
depending upon whether the arrangement of the halo-
gen on the central carbon atom is syn or anti with
respect to the isocyanide ligand. The 1H NMR data
showed that both isomers are present in the reaction
mixture, as revealed by the appearance of two triplets
It must be noted that, in these reactions, an excess
of dihalogen must be employed in order to avoid the
formation of a mixture containing, in addition to 3a -
t
at about δ 6 for the P2C(H)X protons and of two Bu
singlets (see Table 1). However, when a solution of
compound 3b or 3d in CH2Cl2 was set aside at room
(9) du Mont, W. W.; Batcher, M.; Pohl, S.; Saak, W. Angew. Chem.,
Int. Ed. Engl. 1987, 26, 912.

4564 Organometallics, Vol. 17, No. 21, 1998
Ruiz et al.
Ta ble 1. Selected Sp ectr oscop ic Da ta for th e New Com p ou n d s
1H NMRb
31P{1H} NMRb
13C {1H} NMRb
a
a
compd
νCO
νCN
1
[Mn(CO)4{(Ph2P)2C(H)Br}]Br3 (3a )
2097 s, 2038 m,
2016 vs
2049 s, 1989 s
6.23 (t, P2CHBr,
2J PH ) 10)
41.0 (s, br)
43.7 (t, P2C, J PC ) 10)
1
fac-[Mn(CNtBu)(CO)3{(Ph2P)2C(H)Br}]Br3 (3b)
2180 m
2180 m
0.95 (s, CNtBu),
6.04 (t, P2CHBr,
2J PH ) 10)c
45.3 (s, br)
43.1 (t, P2C, J PC ) 8)
1
[Mn(CO)4{(Ph2P)2C(H)I}]I3 (3c)
2096 s, 2037 m,
2015 vs
2047 s, 1988 s
6.46 (t, P2CHI,
33.0 (s, br)
37.3 (s, br)
15.2 (t, P2C, J PC ) 10)
2J PH ) 11)
1
fac-[Mn(CNtBu)(CO)3{(Ph2P)2C(H)I}]I3 (3d )
0.87 (s, CNtBu),
6.07 (t, P2CHI,
2J PH ) 11)c
14.5 (t, P2C, J PC ) 7)
1
[Mn(CO)4{(Ph2P)2CBr}] (4a )
2075 s, 1995 vs,
1965 s
2017 vs, 1953 s, 2174 m
1936 s
2074 s, 1993 vs,
1965 s
2016 vs, 1951 s, 2173 m
1937 s
2100 s, 2041 m,
2025 vs
2051 s, 1993 s
2023 s, 1960 s, 2177 m,
1945 s
10.1 (s, vbr)
16.7 (s, br)
5.2 (s, br)
1.2 (t, P2C, J PC ) 50)
fac-[Mn(CNtBu)(CO)3{(Ph2P)2CBr}] (4b)
[Mn(CO)4{(Ph2P)2Cl}] (4c)
0.71 (s, CNtBu)
0.73 (s, CNtBu)
1.0 (t, P2C, J PC ) 46)
1
1
-34.7 (t, P2C, J PC ) 46)
fac-[Mn(CNtBu)(CO)3{(Ph2P)2Cl}] (4d )
[Mn(CO)4{(Ph2P)2CBr2}]Br3 (5a )
12.1 (s, br)
75.0 (s, br)
-35.3 (t, P2C, J PC ) 50)
1
1
64.4 (t, P2C , J PC ) 3)
1
fac-[Mn(CNtBu)(CO)3{(Ph2P)2CBr2}]Br3(5b)
fac-[Mn(CNtBu)(CO)3{(Ph2P)2CCN}] (6b)
2184 m
1.17 (s, CNtBu)
0.67(s, CNtBu)
81.7 (s, br)
10.6 (s, br)
64.8 (t, P2C, J PC ) 7)
1
17.7 (t, P2C, J PC ) 56)
2143 m
2240 w,
2182 m
fac-[Mn(CNtBu)(CO)3{(Ph2P)2C(H)CN}]BF4 (7b)
2052 s, 1992 s
0.88 (s, CNtBu),c
6.53 (t, P2CH,
2J PH ) 11)d
35.5 (s, br)d
1
fac-[Mn(CNtBu)(CO)3{(Ph2P)2CSCN}] (8b)
2020 s, 1955 s, 2174 m,
1944 s 2135 w
2181 m,
2159 w
0.77 (s, CNtBu)
30.9 (s, br)
48.1 (s, br)d
12.7 (t, P2C, J PC ) 44),
3
117.2 (t, SCN, J PC ) 4)
1
fac-[Mn(CNtBu)(CO)3{(Ph2P)2C(H)SCN}]BF4 (9b) 2051 s, 1992 s
fac-[Mn(CNtBu)(CO)3{(Ph2P)2C(H)SePh}]BF4 (10b) 2045 s, 1984 s
0.85 (s, CNtBu),c
6.39 (t, P2CH,
2J PH ) 10)d
48.5 (t, P2C, J PC ) 9)
1
2178 m
1.22 (s, CNtBu),c
5.59 (t, P2CH,
2J PH ) 12)d
44.9 (s, br)d
59.0 (t, P2C, J PC ) 10)
1
fac-[Mn(CNtBu)(CO)3{(Ph2P)2CSePh}] (11b)
2015 s, 1951 s, 2169 m
1935 s
0.89 (s, CNtBu)
18.1 (s, br)
17.3 (t, P2C, J PC ) 40)
a
b
In units of cm-1 (measured in CH2Cl2). Abbreviations: v ) very, s ) strong, m ) medium, w ) weak. Chemical shifts (δ) in ppm
(measured in CD2Cl2); coupling constants in Hz. Abbreviations: s ) singlet, t ) triplet, br ) broad. c These data correspond to the anti
isomers (see text). Data for the syn isomers are as follows: 3b, 1.15 (s, CNtBu), 6.11 (t, P2CHBr, J PH ) 10); 3d , 1.11 (s, CNtBu), 6.09 (t,
2
P2CHBr, 2J PH ) 11); 7b, 1.18 (s, CNtBu), 6.98 (t, P2CH, 2J PH ) 9); 9b, 0.99 (s, CNtBu), 6.23 (t, P2CH, 2J PH ) 10); 10b, 0.92 (s, CNtBu), 5.74
2
d
(t, P2CH, J PH ) 12). In CDCl3.
temperature, successive proton spectra showed slow
conversion from one isomer to the other. After several
days, only one isomer was present, which could be the
one with the halogen arranged anti with respect to the
bulky CNtBu ligand. To confirm this and to gain
knowledge about the structural data of the new diphos-
phine, an X-ray diffraction study was carried out for 3b.
A view of the complex cation is depicted in Figure 1,
showing the manganese in a distorted-octahedral coor-
dination geometry. As was anticipated, the bromine
atom is located anti with respect to the isocyanide
ligand, this being due apparently to steric reasons. The
C(1)-Br(1) bond length (1.98(1) Å) is typical of bromoal-
kanes,10 and the P(1)-C(1) (1.82(1) Å) and P(2)-C(1)
(1.83(1) Å) distances are of the same order as those
usually found in dppm derivatives (single bond P-C).
These data are consistent with a sp3 hybridization for
carbon C(1), although the bond angles around this atom
(P(1)-C(1)-P(2) ) 99.0(4)°, P(1)-C(1)-Br(1) ) 120.0-
(5)°, P(2)-C(1)-Br(1) ) 121.4(5)°) indicate a strongly
distorted tetrahedral coordination geometry, arising
from the strain introduced by the small bite angle of
the diphosphine and from the different size and nature
of the carbon substituents.
F igu r e 1. X-ray structure of the cation of 3b, fac-[Mn-
(CNtBu)(CO)3{(PPh2)2C(H)Br}]+, showing 30% probability
ellipsoids. Selected bond distances (Å) and angles (deg):
C(1)-Br(1) ) 1.98(1), P(1)-C(1) ) 1.82(1), P(2)-C(1) )
1.83(1), Mn-P(1) ) 2.299(5), Mn-P(2) ) 2.341(4); P(1)-
C(1)-P(2) ) 99.0(4), P(1)-C(1)-Br(1) ) 120.0(5), P(2)-
C(1)-Br(1) ) 121.4(5), P(1)-Mn-P(2) ) 73.6(2).
The diphosphines (PPh2)2C(H)X in complexes 3a -d
are able to react with bases in two different ways. In
fact the experiments show that both substituents at the
central carbon atom, hydrogen and halogen, are elec-
trophilic in character and can be abstracted as H+ or
X+ depending upon the nature of the nucleophile used.
Thus, the reaction of a dichloromethane solution of
3a -d toward a hard nucleophile such as OH- (from
(10) Trotter, J . In The Chemistry of the Carbon-Halogen Bond;
Patai, S., Ed.; Wiley: New York, 1973; Part I, p 50.

Bis(diphenylphosphino)methanide Complexes of Mn(I)
Organometallics, Vol. 17, No. 21, 1998 4565
KOH) takes place with proton abstraction, leading to
the formation of [Mn(L)(CO)3{(Ph2P)2CX}] (4a-d). How-
ever, when a soft nucleophile such as PPh3 is employed,
dehalogenation of the diphosphine immediately occurs
to give finally [Mn(L)(CO)3{(Ph2P)2CH2}]+ (1a -d ). As
shown in Scheme 1, we propose for this last reaction a
mechanism involving, in a first step, the formation of
[Mn(L)(CO)3{(Ph2P)2CH}] (2a -d ) and the phosphonium
cation [XPPh3]+, which is acidic enough to protonate
2a -d , affording 1a -d . Supporting this, in an indepen-
dent experiment we have proved that a dichloromethane
solution of 2b readily reacts with freshly prepared
[IPPh3]+I-,11 affording 1b, in addition to other phos-
phorus-containing species which so far remain unchar-
acterized.
with an excess of HBF4 in CH2Cl2 led to the formation
of 7b, which has been spectroscopically characterized
but not isolated as a pure compound because it slowly
changes to 6b on removing the excess acid. The IR
spectrum of 6b in CH2Cl2, in the region 2200-1800
cm-1, shows, in addition to the νCO and νCN bands of
carbonyls and isocyanide, a new νCN absorption at 2143
cm-1 corresponding to the cyano substituent of the
methanide. As far as we know, the only complex that
has been described previously containing a cyano-
diphosphinomethanide ligand is the dinuclear species
[Fe2(CO)6(µ-PPh2){η2-(P,P′)-µ-(PPh2)2CCN}],13 which was
formed in a rather unexpected way.
The reaction of 2b with BrCN yields directly the
bromination product 4b and not the cyanation product
6b. In fact, this is a clean one-step synthetic procedure
for obtaining 4b. Basically, this result can be rational-
ized by assuming a Brδ+CNδ- charge distribution for
this reagent, which forces the nucleophilic attack of the
methanide to take place on the bromine atom.
The methanide complex 2b was also able to react
under mild conditions with thiocyanogen, (SCN)2, af-
fording a mixture of the new thiocyanate-diphosphi-
nomethanide derivative fac-[Mn(CNtBu)(CO)3{(Ph2P)2-
CSCN}] (8b) and the starting dppm complex 1b. After
column chromatography, 8b was isolated as colorless
crystals. Its spectroscopic data are consistent with a
thiocyanate structure for the new ligand, [(Ph2P)2-
CSCN]-, rather than its isomeric isothiocyanate form
[(Ph2P)2CNCS]-. Thus, the IR spectrum of 8b shows a
sharp band at 2135 cm-1, which is in the range corre-
sponding to organic thiocyanates.14 Furthermore, in the
13C{1H} NMR spectrum, the resonance of the -SCN
carbon appears as a triplet at δ 117.2 (3J PC ) 4 Hz).14
8b readily reacts with HBF4 to give the cationic complex
fac-[Mn(CNtBu)(CO)3{(Ph2P)2C(H)SCN}]+ (9b), which
should be the intermediate species in the formation of
8b. This was stable enough to be isolated as a white
solid, which was fully characterized (see Table 1 and
Experimental Section).
Finally, the reaction of 2b with ISePh promotes the
heterolytic cleavage of the I-Se bond to give a mixture
of fac-[Mn(CNtBu)(CO)3{(Ph2P)2C(H)SePh}]+ (10b), fac-
[Mn(CNtBu)(CO)3{(Ph2P)2CSePh}] (11b), and 1b. After
treatment with KOH and further column chromatog-
raphy, 11b was isolated as a white solid in 80% yield.
As expected, a protonation reaction carried out on 11b
with HBF4 afforded 10b.
A general consideration to be made regarding all the
cationic species fac-[Mn(CNtBu)(CO)3{(Ph2P)2C(H)CN}]+
(7b), fac-[Mn(CNtBu)(CO)3{(Ph2P)2C(H)SCN}]+ (9b),
and fac-[Mn(CNtBu)(CO)3{(Ph2P)2C(H)SePh}]+ (10b) is
that they appear as a mixture of two isomers, arising
from the relative syn and anti dispositions of the
substituent CN, SCN, or SePh of the diphosphine, with
respect to the CNtBu ligand. This is shown by the
spectroscopic data of these complexes (see Table 1),
especially by the appearance of two P2C(H)- triplets
at about δ 6.5 and two CNtBu resonances in the proton
spectra. However, when it stands in CH2Cl2 at room
In the 13C{1H} NMR spectra of 4a -d the resonances
for the P2CX carbon atoms appear at remarkably high
1
fields (see Table 1), and the values of J PC (about 50
Hz) are much higher than those in 3a -d (about 10 Hz),
owing to the higher degree of s character of the central
carbon atom in 4 (sp2) compared to that in 3 (sp3).12
Although complexes of type 4 are less reactive than
2 toward electrophilic agents, in some cases they are
still able to react properly with dihalogen molecules.
Thus, the treatment of 4a ,b with Br2 in CH2Cl2 causes
another heterolytic cleavage of the dihalogen to give the
cationic complexes [Mn(L)(CO)3{(Ph2P)2CBr2}]Br3 (5a,b).
In contrast, the reaction of 4c,d with I2 in CH2Cl2 gave
an intractable mixture of species, the spectroscopic data
of which indicate that double C-iodination of the diphos-
phine might occur, but only partially. In 5a ,b the
bromine atoms of the diphosphine are electrophilic, as
is proved by their reaction with KOH to afford 4a ,b. It
must be noted that the diphosphine [(Ph2P)2CBr2] is a
curious example of a molecule containing a tetrahedral
carbon atom only surrounded by heteroatoms (core P2-
CBr2).
Rea ction s of fa c-[Mn (CNtBu )(CO)3{(P h 2P )2CH}]
(2b) w ith P seu d oh a logen s. In the search for new
types of functionalized diphosphines and in view of the
reactivity of the methanide derivatives 2a ,b toward
dihalogens, we extended the study of this reactivity to
di-pseudohalogen molecules, such as (CN)2, BrCN,
(SCN)2, and ISePh. We have found that these molecules
undergo heterolytic cleavage of C-C, Br-C, S-S, and
I-Se bonds, respectively.
The reaction of 2b with cyanogen leads to the forma-
tion of fac-[Mn(CNtBu)(CO)3{(Ph2P)2CCN}] (6b) to-
gether with an equivalent amount of the dppm deriva-
tive fac-[Mn(CNtBu)(CO)3{(Ph2P)2CH2}]+ (1b ) (see
Scheme 1). Both complexes are easily separated by
column chromatography. On the basis of that found in
the reaction of 2b with dihalogens, we propose that the
present reaction takes place through the formation of
the cationic intermediate fac-[Mn(CNtBu)(CO)3{(Ph2P)2C-
(H)CN}]+ (7b) (which is comparable to complexes of type
3), in which the highly acidic character of the P2C(H)-
CN hydrogen promotes a proton transfer to 2b, affording
the final observed mixture. In fact, the reaction of 6b
(11) Godfrey, S. M.; Kelly, D. G.; McAuliffe, C. A.; Mackie, A. G.;
Pritchard, R. G.; Watson, S. M. J . Chem. Soc., Chem. Commun. 1991,
1163.
(12) Phosphorus-31 NMR Spectroscopy in Stereochemical Analysis:
Organic Compounds and Metal Complexes; Verkade, J . G., Quin, L.
D., Eds.; VCH: New York, 1987; p 398.
(13) Yuan-Fu, Y.; Wojcicki, A.; Calligaris, M.; Nardin, G. Organo-
metallics 1986, 5, 47.
(14) Ben-Efraim, D. A. In The Chemistry of Cyanates and their Thio
Derivatives; Patai, S., Ed.; Wiley: New York, 1977; Part I, pp 226-
227.

4566 Organometallics, Vol. 17, No. 21, 1998
Ruiz et al.
for C29H20IMnO4P2: C, 51.51; H, 2.98. Found: C, 51.23; H,
2.80. Pale yellow crystals of 4c‚CH2Cl2, suitable for X-ray
diffraction study, were obtained by recrystallization from CH2-
Cl2/hexane.
fa c-[Mn (CNtBu )(CO)3{(P h 2P )2CI}] (4d ). This was simi-
larly prepared from 3d (0.25 g, 0.22 mmol) and KOH (1 g).
Yield: 0.15 g (90%). Anal. Calcd for C33H29IMnNO3P2: C,
54.19; H, 1.91; N, 4.00. Found: C, 54.01; H, 1.94; N, 3.99.
temperature, the mixture slowly changes to one isomer
only, which should be the anti one on the basis of the
structure found for the very similar complex 3b (see
above).
Exp er im en ta l Section
Gen er a l Com m en ts. All reactions were carried out under
a nitrogen atmosphere with the use of Schlenk techniques.
Solvents were dried and purified by standard techniques and
distilled under nitrogen prior to use. All reactions were
monitored by IR spectroscopy (Perkin-Elmer FT 1720-X and
Paragon 1000 spectrophotometers). The C, H, and N analyses
were performed on a Perkin-Elmer 240B elemental analyzer.
1H, 13C, and 31P NMR spectra were measured with Bruker AC-
300 and AC-200 instruments. Chemical shifts are given in
ppm, relative to internal SiMe4 (1H, 13C) or external 85% H3-
PO4 (31P). The complexes [Mn(CO)4{(Ph2P)2CH}] (2a ) and fac-
[Mn (CO)4{(P h 2P )2CBr 2}]Br 3 (5a ). A solution of 4a (0.15
g, 0.24 mmol) in 20 mL of CH2Cl2 was added dropwise to an
excess of bromine (61 µL, 1.18 mmol). The resulting mixture
was stirred for 10 min. The solvent was then evaporated to
dryness under reduced pressure. The residue was washed
with hexane (20 mL), giving a yellow solid (0.21 g, 93%). The
product can be recystallized from CH2Cl2/hexane. Anal. Calcd
for C29H20Br5MnO4P2: C, 36.71; H, 2.12. Found: C, 36.51; H,
2.08.
fa c-[Mn (CNtBu )(CO)3{(P h 2P )2CBr 2}]Br 3 (5b). This was
similarly prepared from 4b (0.20 g, 0.29 mmol) and Br2 (80
µL, 1.55 mmol). Anal. Calcd for C33H29Br5MnNO3P2: C, 39.48;
H, 2.91; N, 1.39. Found: C, 39.57; H, 2.95; N, 1.41.
fa c-[Mn (CNtBu )(CO)3{(P h 2P )2CCN}] (6b). To a solution
of 2b (0.30 g, 0.49 mmol) in CH2Cl2 (25 mL), (CN)2 was bubbled
through. The reaction was monitored by IR spectroscopy, until
all the starting material had been consumed (about 1 h).
Bands corresponding to 1b and 6b were observed. The
solution was then evaporated to dryness and the remaining
solid chromatographed through an alumina column (activity
III). Elution with CH2Cl2/hexane (1:2) and evaporation of the
solvent give the desired product 6b as a white solid. Yield:
0.11 g (35%). Anal. Calcd for C34H29MnN2O3P2: C, 64.77; H,
4.63; N, 4.44. Found: C, 64.73; H, 4.64; N, 4.13.
15
[Mn(CNtBu)(CO)3{(Ph2P)2CH}] (2b)8 and the reagents (CN)2
and (SCN)216 were prepared as described elsewhere. All other
reagents were commercially obtained and were used without
further purification.
[Mn (CO)4{(P h 2P )2C(H )Br }]Br 3 (3a ).
A solution of
[Mn(CO)4{(Ph2P)2CH}] (2a ; 0.20 g, 0.36 mmol) in 20 mL of
CH2Cl2 was added dropwise to an excess of bromine (0.13 mL,
2.54 mmol) at room temperature with continuous stirring. The
solvent was then evaporated to dryness and the residue
washed with hexane (30 mL) and dried under vacuum.
A
yellow crystalline solid was obtained (0.30 g, 96%). The
product can be recrystallized from CH2Cl2/hexane. Anal.
Calcd for C29H21Br4MnO4P2: C, 40.04; H, 2.43. Found: C,
40.37; H, 2.34.
fa c-[Mn (CNtBu )(CO)3{(P h 2P )2C(H)Br }]Br 3 (3b). The pro-
cedure is completely analogous to that described above, using
fac-[Mn(CNtBu)(CO)3{(Ph2P)2CH}] (2b; 0.20 g, 0.33 mmol) and
Br2 (0.12 mL, 2.31 mmol). Yield: 0.26 g (85%). Anal. Calcd
for C33H30Br4MnNO3P2: C, 42.84; H, 3.27; N, 1.51. Found: C,
42.97; H, 3.24; N, 1.46. Slow diffusion of hexane into a CH2-
Cl2 solution of the compound afforded yellow crystals suitable
for X-ray diffraction study.
[Mn (CO)4{(P h 2P )2C(H)I}]I3 (3c). This was similarly pre-
pared from 2a (0.20 g, 0.36 mmol) and I2 (0.64 g, 2.54 mmol):
red crystals from CH2Cl2/hexane. Yield: 0.29 g (76%). Anal.
Calcd for C29H21I4MnO4P2: C, 32.92; H, 2.00. Found: C, 32.71;
H, 1.93.
fa c-[Mn (CNtBu )(CO)3{(P h 2P )2C(H)I}]I3 (3d ). This was
similarly prepared from 2b (0.20 g, 0.33 mmol) and I2 (0.59 g,
2.32 mmol): brown-red solid. Yield: 0.26 g (70%). Anal.
fa c-[Mn (CNtBu )(CO)3{(P h 2P )2CSCN}] (8b). To a solu-
tion of 2b (0.35 g, 0.58 mmol) in 15 mL of CH2Cl2 was added
a solution containing (SCN)2 (45 mg, 0.38 mmol) in 15 mL of
CH2Cl2 dropwise with continuous stirring. The reaction occurs
instantaneously, giving a mixture of 1b and 8b (by IR
spectroscopy). The solution was then evaporated to dryness
and the remaining solid chromatographed through an alumina
column (activity III). Elution with CH2Cl2/hexane (1:2) and
evaporation of the solvent give 8b as a white solid. Yield: 0.13
g (34%). Anal. Calcd for C34H29MnN2O3P2S: C, 61.64; H, 4.41;
N, 4.23. Found: 61.33; H, 4.35; N, 4.12.
fa c-[Mn (CNtBu )(CO)3{(P h 2P )2C(H)SCN}]BF 4 (9b). To a
solution of 8b (0.1 g, 0.15 mmol) in 15 mL of CH2Cl2 was added
tetrafluoroboric acid-diethyl ether complex (85%; 52 µL, 0.30
mmol) with stirring. The formation of 9b takes place instan-
taneously. The solvent was then evaporated to dryness and
the residue washed with diethyl ether (3 × 5 mL). A white
solid was formed, which was recrystallized from CH2Cl2/
hexane. Yield: 96 mg (85%). Anal. Calcd for C34H30BF4-
MnN2O3P2S: C, 54.42; H, 4.03; N, 3.73. Found: C, 54.63; H,
4.20; N, 3.60.
fa c-[Mn (CNtBu )(CO)3{(P h 2P )2CSeP h }] (11b). A solution
of 2b (0.2 g, 0.33 mmol) in 20 mL of CH2Cl2 was added
dropwise to ISePh (93 mg, 33 mmol) with continuous stirring.
Once the addition was finished, the resulting mixture was
treated with an excess of KOH (1 g) and stirred for 30 min.
The solution was filtered off and evaporated to dryness to give
a pale yellow residue. This was chromatographed through an
alumina column (activity III), using CH2Cl2/hexane (1:1) as
eluent. Evaporation of the solvent to dryness gave 11b as a
Calcd for
C33H30I4MnNO3P2: C, 35.61; H, 2.72; N, 1.26.
Found: C, 35.73; H, 2.68; N, 1.30.
[Mn (CO)4{(P h 2P )2CBr }] (4a ). An excess of KOH (1 g) was
added to a solution of 3a (0.2 g, 0.23 mmol) in 20 mL of CH2-
Cl2. The mixture was stirred until the IR spectrum of the
solution showed no bands corresponding to 3a (2 h ap-
proximately). The resulting yellow solution was filtered off
and concentrated to 5 mL. Addition of hexane and cooling
(-20 °C) gave yellow crystals of the product. Yield: 0.12 g
(83%). Anal. Calcd for C29H20BrMnO4P2: C, 55,35; H, 3.20.
Found: C, 55.31; H, 3.20.
fa c-[Mn (CNtBu )(CO)3{(P h 2P )2CBr }] (4b). The procedure
is completely analogous to that described above, using 3b (0.25
g, 0.27 mmol) and KOH (1 g). Yield: 0.18 g (90%). Anal. Calcd
for C33H29BrMnNO3P2: C, 57,91; H, 2.05; N, 4.27. Found: C,
57.84; H, 2.15; N, 4.27.
white solid. Yield: 0.20 g (80%). Anal. Calcd for C39H34
-
MnNO3P2Se: C, 61.59; H, 4.50; N, 1.84. Found: C, 61.11; H,
4.58; N, 1.89.
[Mn (CO)4{(P h 2P )2CI}] (4c). This was similarly prepared
from 3c (0.15 g, 0.14 mmol). Yield: 77 mg (81%). Anal. Calcd
fa c-[Mn (CNt Bu )(CO)3{(P h 2P )2C(H)SeP h }]BF 4 (10b ).
This was prepared similarly to 9b, starting from 11b (0.10 g,
0.13 mmol) and HBF4‚Et2O (85%, 45 µL, 0.26 mmol). Yield:
89 mg (80%). Anal. Calcd for C39H35BF4MnNO3P2Se: C,
55.21; H, 4.16; N, 1.65. Found: C, 55.45; H, 4.28; N, 1.54.
(15) Holliday, A. K.; Hughes, G.; Walker, S. M. In Comprehensive
Inorganic Chemistry; Trotman-Dickenson, A. F., Ed.; Pergamon
Press: Oxford, U.K., 1975; Vol 1, p 1241.
(16) Reference 15, p 1247.

Bis(diphenylphosphino)methanide Complexes of Mn(I)
Organometallics, Vol. 17, No. 21, 1998 4567
Ta ble 2. Su m m a r y of Cr ysta llogr a p h ic Da ta
Isotropic full-matrix least-squares refinement on F using
SHELX7619 converged to R ) 0.17. At this stage additional
empirical absorption correction was performed using DI-
FABS.20 Maximum and minimum correction factors were 1.00
and 0.35, respectively. All non-hydrogen atoms were aniso-
tropically refined on F2 using SHELXL93.21 The drawing of
the complex shown in Figure 1 was made using EUCLID.22
compd
3b
emp formula
fw
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
C
33H30Br4MnNO3P2
925.10
monoclinic
C2/c
32.76(8)
11.236(2)
21.195(3)
90
110.99(7)
90
7286(18)
8
Ack n ow led gm en t. We gratefully acknowledge the
Spanish Ministerio de Educacion y Ciencia for financial
assistance (Project Nos. DGE-96-PB-0317 and 0556).
Su p p or tin g In for m a tion Ava ila ble: Text giving details
of the crystal data and tables of crystal data, atomic coordi-
nates and Ueq values, interatomic distances and angles, and
anisotropic displacement parameters for 3b (8 pages). Order-
ing information is given on any current masthead page.
Z
d(calcd) (g/cm3)
1.687
4.870
293(2)
µ (mm-1
T, K
)
wavelength (Å)
diffractometer
θ range (deg)
0.710 73
CAD4 Nonius
1.33-22.99
0.0548; 0.1631
0.905
OM980391E
residuals: R1;a wR2b
goodness of fit
(17) Sheldrick, G. M. In Crystallographic Computing 3; Sheldrick,
G. M., Kruger, C., Goddard, R., Eds.; Clarendon Press: Oxford, U.K.,
1985; pp 175-189.
(18) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garc´ıa-Granda, S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C. The
DIRDIF92 Program System; University of Nijmegen: Nijmegen, The
Netherlands, 1992.
(19) Sheldrick, G. M. SHELX76: Program for Crystal Structure
Determination; University of Cambridge, Cambridge, U.K., 1976.
(20) Walker, N.; Stuart, D. Acta Crystallogr. 1983, A39, 158.
(21) Sheldrick, G. M. In Crystallographic Computing 6; Flack, H.
D., Pa´rka´nyi, L., Simon, K., Eds.; International Union of Crystal-
lography and Oxford University Press: Oxford, U.K., 1993; pp 111-
122.
(∆/σ)min (e Å-3
)
)
-0.732
0.684
(∆/σ)max (e Å-3
a
b
R1 ) ∑|∆F|/∑|Fo|. wR2 ) [∑w(∆F)2/∑w(Fo)2]1/2
.
X-r a y Cr ysta llogr a p h y. Crystals of 3b suitable for X-ray
diffraction analysis were grown from a dichloromethane solu-
tion layered with hexane at 25 °C. Data collection, crystal,
and refinement parameters are summarized in Table 2. Unit
cell parameters were obtained from the least-squares fit of 25
reflections with θ between 9 and 12°. Lorentz and polarization
corrections were applied. The structures were solved by direct
methods using SHELXS8617 and expanded by DIRDIF.18
(22) Spek, A. L. In Computational Crystallography; Sayre, D., Ed.;
Clarendon Press: Oxford, U.K., 1982; p 528.