Thiocyanogen insertion into P-C bonds of diphosphinomethanide complexes, leading to rare functionalized diphosphine and tetraphosphine ligands

Article abstract of DOI:10.1021/om0611195

The complex fac-[Mn(CNtBu)(CO)₃{(PPh₂) ₂C-SCN}] (2) reacts with thiocyanogen, affording the unstable derivative fac-[Mn(CNtBu)(CO)₃{(PPh₂)C(SCN)C(SSCN)N(PPh2)} ] (3), as a result of the insertion of the pseudohalogen molecule into one of the P-C bonds of the diphosphinomethanide ligand. This complex undergoes intermolecular sulfur-sulfur coupling processes, with elimination of the pseudohalogen molecules (SCN)₂, S(CN)₂, and (CN) ₂, to yield a mixture of the dinuclear complexes fac-[{Mn(CNtBu)-(CO) ₃(PPh₂)C(SCN)C(NPPh₂)}₂-S _n] (4-6) linked through polysulfide chains of different lengths. Treatment of these dinuclear disulfide and trisulfide derivatives with 1 or 2 equiv of HBF₄ resulted in the sequential protonation of the nitrogen atoms of the ligand, yielding cationic and dicationic complexes, respectively. In the case of monoprotonated disulfide derivatives ³¹P NMR experiments reveal the existence of an intramolecular proton-transfer process between the endocyclic nitrogen atoms of both metallic fragments. Similar insertion reactions are observed in the treatment of other diphosphinomethanide complexes containing a P₂C-S skeleton such as fac-[Mn(L)(CO) ₃{(PPh₂)₂C-SC(S)NMe₂}] (11a, L = CNtBu; 11b, L = CO) and fac-[Mn(CNtBu)(CO)₃{(PPh₂) ₂C-S(C₅NH₃NO₂)}] (12) with thiocyanogen, yielding new mononuclear derivatives, whose formation implies additionally unusual transposition and cyclization processes. These mononuclear complexes can be protonated on the nitrogen atom by addition of HBF₄, affording complexes containing rare functionalized diphosphine ligands.

Full text of DOI:10.1021/om0611195

Organometallics 2007, 26, 1703-1711
1703
Thiocyanogen Insertion into P-C Bonds of Diphosphinomethanide
Complexes, Leading to Rare Functionalized Diphosphine and
Tetraphosphine Ligands
Javier Ruiz,*,† Roberto Quesada,†,‡ Maril´ın Vivanco,† Santiago Garc´ıa-Granda,§ and
M. Rosario D´ıaz§
Departamento de Qu´ımica Orga´nica e Inorga´nica and Departamento de Qu´ımica F´ısica y Anal´ıtica,
Facultad de Qu´ımica, UniVersidad de OViedo, 33071 OViedo, Spain
ReceiVed December 11, 2006
The complex fac-[Mn(CNtBu)(CO)3{(PPh2)2C-SCN}] (2) reacts with thiocyanogen, affording the
unstable derivative fac-[Mn(CNtBu)(CO)3{(PPh2)C(SCN)C(SSCN)N(PPh2)}] (3), as a result of the insertion
of the pseudohalogen molecule into one of the P-C bonds of the diphosphinomethanide ligand. This
complex undergoes intermolecular sulfur-sulfur coupling processes, with elimination of the pseudohalogen
molecules (SCN)2, S(CN)2, and (CN)2, to yield a mixture of the dinuclear complexes fac-[{Mn(CNtBu)-
(CO)3(PPh2)C(SCN)C(NPPh2)}2-Sn] (4-6) linked through polysulfide chains of different lengths.
Treatment of these dinuclear disulfide and trisulfide derivatives with 1 or 2 equiv of HBF4 resulted in
the sequential protonation of the nitrogen atoms of the ligand, yielding cationic and dicationic complexes,
respectively. In the case of monoprotonated disulfide derivatives 31P NMR experiments reveal the existence
of an intramolecular proton-transfer process between the endocyclic nitrogen atoms of both metallic
fragments. Similar insertion reactions are observed in the treatment of other diphosphinomethanide
complexes containing a P2C-S skeleton such as fac-[Mn(L)(CO)3{(PPh2)2C-SC(S)NMe2}] (11a, L )
CNtBu; 11b, L ) CO) and fac-[Mn(CNtBu)(CO)3{(PPh2)2C-S(C5NH3NO2)}] (12) with thiocyanogen,
yielding new mononuclear derivatives, whose formation implies additionally unusual transposition and
cyclization processes. These mononuclear complexes can be protonated on the nitrogen atom by addition
of HBF4, affording complexes containing rare functionalized diphosphine ligands.
by the methanide carbon atom, similar to what we found for
halogens and other pseudohalogen molecules. In fact, to the
best of our knowledge, there is only one reported example of
thiocyanogen reactivity which proceeds without the cleavage
of the S-S bond, the formation of a 4-H dioxazine by
cycloaddition of (SCN)2 and hexafluoroacetone.5
We have now found that treatment of 2 and other diphos-
phinomethanide complexes containing a P2CS skeleton with
thiocyanogen proceeds quite differently, leading to the insertion
of the pseudohalogen molecule into a P-C bond of the
diphosphinomethanide ligand, a reaction which implies the
breaking of a rather strong bond without cleavage of the
thiocyanogen sulfur-sulfur bond.6 P-C bond cleavage pro-
cesses have attracted a great deal of interest, due to their
implication in deactivation pathways of phosphine complexes
used as homogeneous catalysts.7 This is a known reaction in
Introduction
Thiocyanogen, first reported in 1919,1 is a useful reagent for
the preparation of thiocyanate derivatives in both organic
synthesis2 and coordination chemistry,3 through reaction path-
ways involving almost exclusively breaking of the sulfur-sulfur
bond. Within our studies concerning the reactivity of Mn(I)
diphosphinomethanide complexes with halogens and pseudohalo-
gens, we observed that reaction of fac-[Mn(CNtBu)(CO)3-
{(PPh2)2CH}] (1) with thiocyanogen yielded the thiocyanate-
substituted diphosphinomethanide complex fac-[Mn(CNtBu)
(CO)3{(PPh2)2C-SCN}] (2).4 This reaction involved the het-
erolytic cleavage of the S-S bond in the thiocyanogen molecule
* To whom correspondence should be addressed. E-mail: jruiz@
fq.uniovi.es.
† Departamento de Qu´ımica Orga´nica e Inorga´nica.
‡ Current address: Departamento de Qu´ımica Orga´nica, Facultad de
Ciencias, Universidad Auto´noma de Madrid, 28049 Cantoblanco, Spain.
§ Departamento de Qu´ımica F´ısica y Anal´ıtica.
(5) Roesky, H. W.; Homsy, N. K.; Noltemeyer, M.; Sheldrick, G. M.
Angew. Chem. 1984, 96, 1002-1004; Angew. Chem., Int. Ed. Engl. 1984,
23, 1000-1001.
(1) Soderback, E. E. Justus Liebigs Ann. Chem. 1919, 419, 217.
(2) (a) Guy, R. G. The chemistry of cyanates and their thio derivatives.
In The Chemistry of Functional Groups; Patai, S., Ed.; Interscience, New
York, 1977; Part 2, Chapter 18, p 833. (b) Block, E.; Schwan, A. L. In
ComprehensiVe Organic Synthesis; Trost, B. M., Fleming, I., Semmelhack,
M. F., Eds.; Pergamon: Oxford, U.K., 1991; Vol. 4, p 348.
(3) See for instance: (a) Bennett, M. A.; Bruce, M. I.; Matheson, T. W.
In ComprehensiVe Organometallic Chemistry; Abel, E. W., Stone, F. G.
A., Wilkinson, G., Eds.; Pergamon: Oxford, U.K., 1982; Vol. 4, p 705. (b)
Bruce, M. I. in ref 3a, Vol. 4, p 883. (d) Odomin, J. D. In ref 3a, Vol. 1,
p 289. (d) Puddephatt, R. J. In ComprehensiVe Coordination Chemistry;
Wilkinson, G., Gillard, R. D., McCleverty, J. A., Eds.; Pergamon: Oxford,
U.K., 1987; Vol. 5, p 887.
(6) It is well established that the P-C bonds of diphosphanylmethanide
ligands are significantly shorter than P-C single bonds; see for example:
(a) Karsch, H. H.; Schier, A. J. Chem. Soc., Chem. Commun. 1994, 2703-
2704. (b) Karsch, H. H.; Grauvogl, G.; Kawecki, M.; Bissinger, P.;
Kumberger, O.; Schier, A.; Moller, G. Organometallics 1994, 13, 610-
618. (c) Karsch, H. H.; Keller, U.; Gamper, S.; Moller, G. Angew. Chem.
1990, 102, 297-298; Angew. Chem., Int. Ed. Engl. 1990, 29, 295-296.
(d) Ruiz, J.; Riera, V.; Vivanco, M.; Lanfranchi, M.; Tiripicchio, A.
Organometallics 1996, 15, 1082-1083.
(7) (a) Garrou, P. E. Chem. ReV. 1985, 85, 171-185. (b) Kong, K. C.;
Cheng, C. H. J. Am. Chem. Soc. 1991, 113, 6313-6315. (c) Morita, D. K.;
Stille, J. K.; Norton, J. R. J. Am. Chem. Soc. 1995, 117, 8576-8581. (d)
Goodson, F. E.; Wallow, T. I.; Novak, B. M. J. Am. Chem. Soc. 1997, 119,
12441-12453.
(4) Ruiz, J.; Riera, V.; Vivanco, M.; Garc´ıa-Granda, S.; D´ıaz, M. R.
Organometallics 1998, 17, 4562-4567.
10.1021/om0611195 CCC: $37.00 © 2007 American Chemical Society
Publication on Web 02/27/2007

1704 Organometallics, Vol. 26, No. 7, 2007
Table 1. Selected Spectroscopic Data for Compounds 3-16
Ruiz et al.
compd
IRa ν(CN,CO), cm-1
31P{1H} NMR,b δ
3
4
5
6
7
8
9
10
11a
11b
12
13a
13b
14
15a
15b
16
2172 (m), 2147 (w), 2030 (vs), 1967 (s)
2173 (m), 2142 (w), 2025 (vs), 1961 (s)
2174 (m), 2142 (w), 2026 (vs), 1963 (s)
2174 (m), 2142 (w), 2026 (vs), 1963 (s)
2176 (m), 2053 (vs), 2000 (s), 1969 (m)
2176 (m), 2053 (vs), 1998 (s), 1969 (m)
2172 (m), 2143 (w), 2051 (vs), 2033 (vs), 1996 (s), 1973 (s)
2172 (m), 2143 (w), 2052 (vs), 2032 (vs), 1994 (s), 1972 (s)
2172 (m), 2015 (vs), 1952 (s), 1934 (s)
2074 (s), 1996 (vs), 1963 (s)
2172 (m), 2015 (vs), 1952 (s), 1934 (s)
2172 (m), 2055 (w), 2034 (vs), 1972 (s)
2084 (s), 2057 (w), 2021 (m), 2000 (vs)
2172 (m), 2142 (w), 2029 (vs), 1966 (s)
2178 (m), 2052 (vs), 1990 (s)
70.8 (br), 47.1 (br)
61.1 (br), 47.2 (br)
64.6 (br), 47.4 (br)
67.6 (br), 47.5 (br)
107.8 (d, 2JPP ) 61 Hz), 55.2 (d, 2JPP ) 61 Hz)
107.8 (br), 55.2 (br)
87.7 (br), 51.9 (br)
103.0 (br), 73.4 (br), 52.4 (br), 47.7 (br)
24.3 (s)c
20.0 (s)c
23.2 (s)c
74.2 (d, 2JPP ) 61 Hz), 30.8 (d, 2JPP ) 61 Hz)c
66.0 (br), 25.7 (br)c
69.1 (br), 47.2 (br)c
101.3 (d, 2JPP ) 62 Hz), 34.0 (d, 2JPP ) 62 Hz)c
98.5 (br), 30.0 (br)c
2100 (m), 2041(m), 2017 (vs), 1985 (s)
2173 (m), 2052 (vs), 1997 (s)
101.3 (d, 2JPP ) 88 Hz), 51.6 (d, 2JPP ) 88 Hz)c
a In CH2Cl2 unless noted otherwise. b In CH2Cl2/D2O unless noted otherwise. c In CDCl3.
phosphinidene complex10 or into a P-C bond of strained three-
membered rings of 2H-azaphosphirene complexes11 and the
insertion of electron-poor alkynes into a P-C bond of a
coordinated phosphine ligand.12 Herein we report several
examples of the unconventional reactivity of thiocyanogen
leading to the insertion of this molecule into P-C bonds of
coordinated diphosphinomethanide ligands and of the subsequent
formation of a number of rare functionalized diphosphine and
tetraphosphine ligands. A preliminary communication of this
work has been published.13
Table 2. Selected Bond Lengths (Å) and Angles (deg) in
Compound 4
N(1)-P(1)
N(1)-C(1)
C(1)-C(2)
P(2)-C(2)
C(1)-S(2)
N(2)-P(3)
1.648(3)
N(2)-C(3)
C(3)-C(4)
P(4)-C(4)
C(3)-S(3)
S(2)-S(3)
1.301(5)
1.398(5)
1.785(4)
1.833(4)
2.02(1)
1.298(5)
1.411(5)
1.782(4)
1.824(4)
1.645(3)
P(1)-Mn(1)-P(2)
C(1)-N(1)-P(1)
N(1)-C(1)-C(2)
N(1)-C(1)-S(2)
C(2)-C(1)-S(2)
C(1)-C(2)-P(2)
85.98(4)
C(1)-S(2)-S(3)
C(3)-S(3)-S(2)
C(3)-N(2)-P(3)
N(2)-C(3)-C(4)
N(2)-C(3)-S(3)
C(4)-C(3)-S(3)
105.3(1)
103.9(1)
126.4(3)
131.8(4)
114.9(3)
113.3(2)
125.1(3)
130.8(4)
116.7(3)
112.5(3)
124.7(3)
Results and Discussion
Reaction of fac-[Mn(CNtBu)(CO)3{(PPh2)2C-SCN}] (2)
with 1 equiv of (SCN)2 yields fac-[Mn(CNtBu)(CO)3{(PPh2)C-
(SCN)C(SSCN)N(PPh2)}] (3) as a result of the insertion of the
pseudohalogen molecule into a P-C bond of the ligand
(Scheme 1). Compound 3 was isolated as a white solid and
characterized by spectroscopy (Table 1), by elemental analysis,
and by FAB mass spectrometry. Compound 3 proved to be
unstable when left to stand in solution, slowly decomposing
and therefore precluding the preparation of single crystals for
X-ray analysis. However, the elution of 3 through an alumina
column using CH2Cl2/hexane mixtures leads to the formation
of the dimetallic complexes 4-6, in an approximate ratio of
6:4:1, respectively. Compounds 4-6 are unique polysulfide
derivatives that contain a bridging chain of two to four sulfur
atoms, and are formally made from the coupling of two
molecules of 3 with elimination of the pseudohalogen molecules
(SCN)2, S(CN)2, and (CN)2, respectively (Scheme 1).
Table 3. Selected Bond Lengths (Å) and Angles (deg) in
Compound 5
N(1)-P(1)
N(1)-C(1)
C(1)-C(2)
P(2)-C(2)
C(1)-S(2)
N(2)-P(3)
1.623(8)
1.32(1)
1.43(1)
1.76(1)
1.82(1)
1.629(7)
N(2)-C(3)
C(3)-C(4)
P(4)-C(4)
C(3)-S(3)
S(2)-S(1)
S(1)-S(3)
1.30(1)
1.43(1)
1.79(1)
1.829(9)
2.020(4)
2.025(4)
C(1)-N(1)-P(1)
N(1)-C(1)-C(2)
N(1)-C(1)-S(2)
C(2)-C(1)-S(2)
C(1)-S(2)-S(1)
C(1)-C(2)-P(2)
123.4(7)
129.8(9)
116.8(8)
113.4(8)
103.2(4)
125.1(7)
S(2)-S(1)-S(3)
P(3)-Mn(2)-P(4)
C(3)-N(2)-P(3)
N(2)-C(3)-C(4)
N(2)-C(3)-S(3)
C(4)-C(3)-S(3)
108.7(2)
83.2(1)
123.6(7)
130.4(8)
117.0(7)
112.6(7)
metallic clusters bearing phosphine ligands, usually leading to
the formation of M-P and M-C bonds.8 Other coordinated
phosphine ligands may display P-C bond activation processes
promoted by acid or basic treatments.9 On the other hand, there
are only a handful of reported examples of P-C bond insertions,
such as the insertion of nitriles either into the P-C bond of a
This result could be compared with the S-S coupling process
reported for the related complex [Mn(CO)4{(PPh2)2C-S-I}],
which allows the formation of the dimetallic disulfide derivative
[(CO)4Mn{(PPh2)2C-S-S-C(PPh2)2}Mn(CO)4],14 with elimi-
nation of I2, on passing the complex through an alumina
column.15 Since the formation of 4-6 from 3 requires the
(8) See, for example: (a) Xia, C.-G.; Yang, K.; Bott, S. G.; Richmond,
M. G. Organometallics 1996, 15, 4480-4487. (b) AÄ lvarez, M. A.; Garc´ıa,
M. E.; Riera, V.; Ruiz, M. A.; Falvello, L. R.; Bois, C. Organometallics
1997, 16, 354-364. (c) Kabir, S. E.; Miah, Md. A.; Sarker, N. C.; Hussain,
G. M. G.; Hardcastle, K. I.; Nordlander, E.; Rosenberg, E. Organometallics
2005, 24, 3315-3320. (d) Watson, W. H.; Wu, G.; Richmond, M. G.
Organometallics 2006, 25, 930-945.
(10) Schiffer, M.; Scheer, M. Angew. Chem. 2001, 113, 3520-3523;
Angew. Chem., Int. Ed. 2001, 40, 3413-3416.
(11) Streubel, R.; Wilkens, H.; Jones, P. G. Chem. Eur. J. 2000, 6, 3997-
4000.
(9) (a) Geldbach, T. J.; Pregosin, P. S. Eur. J. Inorg. Chem. 2002, 8,
1907-1918 and references cited therein. (b) Bott, S. G.; Yang, K.;
Richmond, M. G.; Talafuse, K. A. Organometallics 2003, 22, 1383-1390.
(c) Quesada, R.; Ruiz, J.; Riera, V.; Garc´ıa-Granda, S.; D´ıaz, M. R. Chem.
Commun. 2003, 1942-1943. (d) Caballero, A.; Jalon, F. A.; Manzano, B.
R.; Espino, G.; Perez-Manrique, M.; Mucientes, A.; Poblete, F. J.; Maestro,
M. Organometallics 2004, 23, 5694-5706. (e) Ruiz, J.; Garc´ıa-Granda,
S.; D´ıaz, M. R.; Quesada, R. Dalton Trans. 2006, 4371-4376.
(12) Yamamoto, Y.; Sugawara, K. Dalton Trans. 2000, 2896-2897.
(13) Ruiz, J.; Quesada, R.; Riera, V.; Vivanco, M.; Garc´ıa-Granda, S.;
D´ıaz, M. R. Angew. Chem., Int. Ed. 2003, 42, 2392-2395.
(14) Ruiz, J.; Ceroni, M.; Quinzani, O. V.; Riera, V.; Vivanco, M.;
Garc´ıa-Granda, S.; Van der Maelen, F.; Lanfranchi, M.; Tiripicchio, A.
Chem. Eur. J. 2001, 7, 4422-4430.
(15) Ruiz, J.; Ceroni, M.; Quinzani, O. V.; Riera, V.; Piro, O. E. Angew.
Chem. 2001, 113, 226-228; Angew. Chem., Int. Ed. 2001, 40, 220-222.

Rare Diphosphine and Tetraphosphine Ligands
Organometallics, Vol. 26, No. 7, 2007 1705
Scheme 1. Synthesis of Compounds 3-6a
Figure 1. X-ray crystal structure of compound 4 (hydrogen atoms
and phenyl groups removed for clarity). Thermal ellipsoids are
drawn at the 30% probability level.
a [Mn] ) [Mn(CNtBu)(CO)3]+.
Scheme 2. Synthesis of Compounds 7-10a
Figure 2. X-ray crystal structure of compound 5 (hydrogen atoms
and phenyl groups removed for clarity). Thermal ellipsoids are
drawn at the 30% probability level.
scission of two S-S bonds, one S-S bond and one S-C bond,
and two S-C bonds, respectively, the relative amount of each
compound in the reaction mixture could be explained by
considering the weakness of the S-S bond versus the S-C bond
in the inserted thiocyanogen molecule. Complexes 4-6 are
isolated as white solids and have very similar spectroscopic
features and solubilities. Thus, the IR spectra for the three
species are virtually identical in the CO and CN stretching
regions, and the complexes can only be distinguished by the
slight differences in the chemical shift of one of the two
nonequivalent phosphorus atoms in the 31P{1H} NMR spectra
(see Table 1). Nevertheless, the major species, 4 and 5, could
be separated by chromatographic workup and were fully
characterized, including the elucidation of their solid-state
structures by X-ray crystallography (Figures 1 and 2 and Tables
2 and 3). The minor product 6 could not be totally purified, as
it always contains some amount of 5; therefore, its characteriza-
tion is based mainly on the FAB mass spectrum.
The structure of complex 4 (Figure 1) formally contains a
thiocyanogen molecule inserted into two P-C(methanide) bonds
of two diphosphinomethanide complexes 2, although, as stated
above, its formation implies a stepwise process of S-S bonds
breaking and forming. The different bond lengths and angles
within the equivalent halves of the molecule are very similar
(Table 2). The bond lengths within the skeleton P1-N1-C1-
C2-P2 of the expanded chelating ligand are intermediate
between single and double bonds, reflecting delocalization of
the negative charge of the methanide carbon atom throughout
that skeleton. The P3, N2, C3, C4, and P4 atoms are essentially
coplanar, with the Mn2 atom out of this plane. The dihedral
angle between the planes defined by P3-Mn2-P4 and P3-
N2-C3 is 44.28°. The other six-membered metallacycle is
twisted, with angles between planes defined by P1-Mn1-P2
and P1-N1-C1 of 47.40°, P1-Mn1-P2 and P2-C2-C1 of
a [Mn] ) [Mn(CNtBu)(CO)3]+.
26.50°, and P1-N1-C1 and P2-C2-C1 of 25.41°. The angle
between the planes defined by N1-C1-S2 and N2-C3-S3 is
85.46°. The S2-S3 bond length (2.02(1) Å) is slightly shorter
than that found in the cyclo-octasulfur molecule (2.06 Å),
whereas the C-S bond lengths (1.828(4) Å on average) are
typical for a single bond. The structure of the trisulfide derivative
5 (Figure 2) is closely related to that of 4, with one more sulfur
atom in the polysulfide chain that links the two diphosphine
rings. Bond distances and angles within the two diphosphine
rings are very similar to those found for 4. The S2-S1-S3
angle (108.7(2)°) is in the range usually found for polysulfide
compounds. Both metallacycles adopt a disposition similar to
that described for compound 4.
Compounds 4 and 5 bear the dianionic bridging ligands
[{PPh2C(SCN)CNPPh2}2Sn]2- (n ) 2, 3), which can be proto-
nated by treatment with HBF4, yielding the dicationic complexes
7 and 8 (Scheme 2). This process is readily reversible by treating
dichloromethane solutions of these derivatives with an excess
of solid KOH. Spectroscopic data suggested that the protonation
takes place on the nitrogen atom of the diphosphine ligand and
not on the original methanide carbon. Thus, IR spectra of these
compounds displayed bands characteristic of cationic fac-
tricarbonyl derivatives, with frequencies notably higher that
those exhibited by the related neutral fragments. Moreover, IR
spectra recorded in a Nujol dispersion showed a characteristic

1706 Organometallics, Vol. 26, No. 7, 2007
Ruiz et al.
Figure 3. IR (CH2Cl2) and 31P{1H} NMR (CH2Cl2/D2O) spectra of neutral, cationic, and dicationic disulfide derivatives 4, 7, and 9 (left)
and neutral, cationic and dicationic trisulfide derivatives 5, 8, and 10 (right).
Figure 5. X-ray crystal structure of compound 14 (hydrogen atoms
and phenyl groups removed for clarity). Thermal ellipsoids are
drawn at the 30% probability level.
More interestingly, neutral complexes 4 and 5 can be
Figure 4. X-ray crystal structure of the complex cation 13b
selectively protonated on only one of the nitrogen atoms by
(hydrogen atoms removed for clarity). Thermal ellipsoids are drawn
treatment with 1 equiv of HBF4 yielding the cationic derivatives
at the 30% probability level.
9 and 10 (Scheme 2). Obviously, these complexes can both be
protonated again by addition of an additional 1 equiv of HBF4
band at 3200 cm-1 assignable to a N-H group. 31P NMR
to give 7 and 8 or deprotonated by treatment with KOH to
regenerate 4 and 5. The IR spectra of 9 and 10 recorded in a
Nujol dispersion showed a band at 3175 cm-1 assignable to an
N-H group. In solution, the IR spectra showed two sets of
bands in the carbonyl stretching region, corresponding to the
two fac-tricarbonyl fragments present in the molecule. Remark-
ably, the frequencies of these fragments are slightly different
from those corresponding to both the parent neutral 4 and 5
and dicationic 7 and 8 derivatives (Figure 3). Thus, bands
assignable to the fac-[Mn(CNtBu)(CO)3] moiety bonded to the
anionic fragment of the ligand appear at frequencies (8 and 6
cm-1 for 9 and 10, respectively) higher than those displayed
by the neutral 4 and 5. The bands corresponding to the cationic
fragment are much more similar to those observed in 7 and 8.
This effect seems to indicate the existence of a relevant
electronic communication through the polysulfide bridge. The
showed that protonation affected the inequivalent phosphorus
atoms of the diphosphine ring very differently. While the
chemical shift of the phosphorus bound to the nitrogen atom is
shifted downfield to approximately 108 ppm as a result of the
protonation of this atom, the other P atom is only slightly
affected. In a independent experiment we have found that a
mixture of compounds 7 and 8 can be obtained by treatment of
the mononuclear derivative 3 with HBF4. Apparently protonation
of the diphosphinomethanide ligand in 3 promotes the elimina-
tion of the pseudohalogen molecules (SNC)2 and S(CN)2 with
formation of sulfur-sulfur bonds, similarly to what occurs when
this compound is eluted through an alumina column. This
process resembles that described for [Mn(CO)4{(PPh2)2C-S-
I}], which is quantitatively converted to the disulfide [(CO)4Mn-
{(PPh2)2C-S-S-C(PPh2)2}Mn(CO)4] by treatment with acid,
eliminating I2.15

Rare Diphosphine and Tetraphosphine Ligands
Organometallics, Vol. 26, No. 7, 2007 1707
Scheme 3. Synthesis of Compound 12a
Table 4. Selected Bond Lengths (Å) and Angles (deg) in
Compound 13b
N(1)-P(1)
N(1)-C(1)
C(1)-C(2)
P(2)-C(2)
C(1)-S(1)
S(1)-C(3)
1.631(4)
1.325(5)
1.384(6)
1.784(4)
1.786(4)
1.714(5)
S(2)-C(3)
S(2)-C(2)
N(2)-C(3)
N(2)-C(4)
N(2)-C(5)
1.712(4)
1.750(4)
1.318(6)
1.466(6)
1.454(6)
P(1)-Mn(1)-P(2)
C(3)-S(1)-C(1)
C(3)-S(2)-C(2)
C(1)-N(1)-P(1)
C(3)-N(2)-C(5)
C(3)-N(2)-C(4)
85.76(4)
96.2(2)
96.1(2)
123.8(3)
121.6(4)
121.5(4)
C(5)-N(2)-C(4)
S(2)-C(3)-S(1)
N(1)-C(1)-S(1)
C(1)-C(2)-S(2)
C(2)-C(1)-S(1)
S(2)-C(2)-P(2)
116. 8(4)
116.3(2)
112.3(3)
117.0(3)
113.9(3)
118.3(2)
Table 5. Selected Bond Lengths (Å) and Angles (deg) in
Compound 14
a [Mn] ) [Mn(CNtBu)(CO)3]+; R ) 5-nitropyridine.
Scheme 4. Formation of the Cationic Complexes 13a,ba
N(1)-P(1)
N(1)-C(1)
C(1)-C(2)
P(2)-C(2)
1.653(2)
1.294(4)
1.396(4)
1.792(3)
C(1)-S(1)
S(1)-S(2)
S(2)-C(51)
1.859(3)
2.034(1)
1.777(3)
P(1)-Mn(1)-P(2)
C(1)-S(1)-S(2)
C(1)-N(1)-P(1)
N(1)-C(1)-C(2)
85.84(4)
N(1)-C(1)-S(1)
C(2)-C(1)-S(1)
C(1)-C(2)-P(2)
C(51)-S(2)-S(1)
114.6(2)
112.5(2)
123.2(2)
103.8(1)
101.3(1)
127.7(2)
132.8(3)
corresponding to average values of the expected chemical shift
for the two types of inequivalent phosphorus atoms present in
the anionic and neutral fragments of the ligand. This result seems
to indicate the existence of an intramolecular proton-transfer
process between both rings of the bridging ligand which is rapid
on the NMR time scale (Figure 3). This process cannot be
completely stopped when the NMR sample is cooled to
-80 °C in CD2Cl2. At this temperature, 31P{1H} NMR spectra
showed a severe broadening of the signals but a new set of
four signals could not be seen. The above results show that the
mobility of the proton atom is dependent on the length of the
sulfur chain, and this can be envisaged in the solid-state
structures of 4 and 5, where the nitrogen atoms are significantly
closer in the disulfane 4 (3.600 Å) than in the trisulfane 5 (5.416
Å). This circumstance could allow the proton-transfer process
in complex 9 to proceed through an intermediate species
featuring an intramolecular N-H‚‚‚N hydrogen bond, similar
to that present in protonated diamines with close nitrogen
atoms.16
a 13a, [Mn] ) [Mn(CNtBu)(CO)3]+; 13b, [Mn] ) [Mn(CO)4]+.
Scheme 5. Synthesis of Compound 14a
a [Mn] ) [Mn(CNtBu)(CO)3]+.
We set out to test the reproducibility of the thiocyanogen
insertion into other diphosphinomethanide derivatives bearing
similar functionalities. We have previously reported the synthesis
of fac-[Mn(CNtBu)(CO)3{(PPh2)2C-SC(S)NMe2}] (11a) by
reaction of fac-[Mn(CNtBu)(CO)3{(PPh2)2C-H}] (1) with tet-
ramethylthiuram disulfide.17 Similarly, 1 readily reacts with
other activated disulfides such as 2,2′-dithiobis(5-nitropyridine),
yielding a mixture of the functionalized diphosphinomethanide
complex 12 and the cationic dppm parent complex, which can
be easily separated after chromatographic workup. A likely
mechanism for the reaction involves the nucleophilic degradation
of the disulfide by the diphosphinomethanide complex followed
by deprotonation of the resultant cationic intermediate by the
starting material (Scheme 3). Compound 12 was fully character-
ized spectroscopically (see Experimental Section).
disappearance of the π component of the P-C bonds in the
metallacycle upon protonation might explain the difference in
the reflection of this electronic communication in the IR of both
carbonyl fragments. The electronic connection between the two
diphosphine rings through the sulfur chain produces a decrease
of the basicity in the anionic diphosphine ring once the other is
protonated. In fact, this process allows the quantitative genera-
tion of compounds 9 and 10 instead of a statistical mixture of
neutral (4 and 5), monocationic (9 and 10), and dicationic (7
and 8) complexes when only 1 equiv of acid is added. Moreover,
9 and 10 can alternatively be prepared by mixing equimolecular
quantities of neutral 4 and 5 and dicationic 7 and 8, in
dichloromethane as solvent. Although 9 and 10 display very
similar IR spectra, 31P NMR experiments reveal significant
differences between these derivatives (Figure 3). Trisulfane 10
displayed four signals corresponding to four inequivalent
phosphorus atoms at 103.0 and 52.4 ppm, assignable to the
protonated part of the ligand, and at 73.4 and 47.7 ppm,
corresponding to the other diphosphine ring, in agreement with
the situation discussed for the IR spectra. On the other hand,
disulfane 9 showed only two signals at 87.5 and 51.9 ppm,
Reaction of fac-[Mn(CNtBu)(CO)3{(PPh2)2C-SC(S)NMe2}]
(11a) with 1 equiv of (SCN)2 at room temperature yields the
cationic derivative 13a, which contains a unique unsymmetrical
(16) Mascal, M.; Lera, M.; Blake, A. J.; Czaja, M.; Kozak, A.; Makowski,
M.; Chmurzynski, L. Angew. Chem., Int. Ed. 2001, 40, 3696-3698.
(17) Ruiz, J.; Quesada, R.; Riera, V.; Garc´ıa-Granda, S.; D´ıaz, M. R.
Chem. Commun. 2003, 2028-2029.

1708 Organometallics, Vol. 26, No. 7, 2007
Table 6. Crystallographic Data for 4, 5, 13b, and 14
Ruiz et al.
4
5
13b
14
empirical formula
formula wt
temp (K)
C70H58Mn2N6O6P4S4
1441.27
293(2)
C70H58Mn2N6O6P4S5
1473.28
293(2)
C34H26MnN3O5P2S2
737.58
293(2)
C42H36Cl4MnN5O5P2S3
1045.62
293(2)
wavelength (Å)
cryst syst, space group
unit cell dimens
a (Å)
b (Å)
c (Å)
1.5418
triclinic, P1h
1.5418
triclinic, P1h
1.5418
triclinic, P1h
1.5418
triclinic, P1h
11.1915(7)
17.3864(7)
18.9243(9)
104.540(3)
94.546(5)
90.072(5)
3552.3(3)
2, 1.347
5.281
11.2755(4)
16.4423(6)
21.966 (1)
72.807(2)
77.227(2)
72.190(3)
3665.6(3)
2, 1.335
5.389
1516
10.5186(7)
10.7753(6)
15.022 (1)
93.073(5)
95.253(4)
92.24 (4)
1691.31(18)
2, 1.448
5.607
11.1806(4)
12.5221(6)
17.1308(7)
102.117(3)
94.625(3)
102.178(2)
2272.52(16)
2, 1.528
R (deg)
â (deg)
γ (deg)
V (Å3)
Z, calcd density (Mg/m3)
abs coeff (mm-1
F(000)
)
6.901
1068
1484
756
cryst size (mm)
θ range for data collecn (deg)
limiting indices
0.063 × 0.038 × 0.038
2.42-69.83
-13 e h e 13,
-21 e k e 20,
0 e l e 23
26 009/13 309
(Rint ) 0.068)
99.1
0.200 × 0.050 × 0.025
2.91-68.13
-12 e h e 13,
-18 e k e 19,
0 e l e 24
21 409/10 418
(Rint ) 0.126)
77.7
0.230 × 0.200 × 0.150
2.96-69.9
-12 e h e 12,
-13 e k e 12,
0 e l e 18
16 304/6329
(Rint ) 0.062)
99
0.380 × 0.350 × 0.150
2.66-69.61
-13 e h e 13,
-14 e k e 14,
0 e l e 20
20 403/8423
(Rint ) 0.081)
98.5
no. of rflns collected/unique
completeness in θ range (%)
abs cor
semiempirical from equivalents
max, min transmissn
refinement method
0.818, 0.632
0.874, 0.681
0.413, 0.320
0.355, 0.132
full-matrix least squares on F2
no. of data/restraints/params
goodness of fit on F2
final R indices (I > 2σ(I))
13 309/0/947
0.926
10 418/0/838
0.844
6329/3/438
1.106
8423/0/703
1.011
R1 ) 0.051,
wR2 ) 0.131
R1 ) 0.073,
wR2 ) 0.142
1.248, -0.875
R1 ) 0.066,
wR2 ) 0.161
R1 ) 0.173,
wR2 ) 0.216
1.272, -0.332
R1 ) 0.066,
wR2 ) 0.200
R1 ) 0.073,
wR2 ) 0.207
1.656, -0.581
R1 ) 0.051,
wR2 ) 0.129
R1 ) 0.056,
wR2 ) 0.139
0.806, -0.587
R indices (all data)
largest diff peak, hole (e Å-3
)
diphosphine ligand featuring a 1,3-dithiol-2-ylidene iminium
group. A possible mechanism for the reaction is proposed in
Scheme 4. As encountered in the case of 2, the first step could
be the insertion of the pseudohalogen molecule into one of the
P-C bonds of the diphosphine, resulting in the expansion of
the metallacycle from four to six members. Then, an intramo-
lecular nucleophilic attack of the thiocarbonyl group from the
dithiocarbamate fragment to the iminic carbon atom of the
diphosphine ring could occur, displacing the SSCN- anion and
resulting in the formation of a dithia heterocycle containing a
dimethyliminium group.
ing to a single bond. Bond angles around the N2 atom are close
to 120°, with the C3, C4, and C5 atoms contained in the same
plane, supporting a sp2 hybridization for this atom. Cyanate
anion was found as the counterion in the crystal structure. As
we discussed in the proposed mechanism, SSCN- should be
displaced and cyanate might be produced in a hydrolysis reaction
of this unstable anion.
Some important features of compounds 13a,b should be
emphasized. Both species contain an unsymmetrical function-
alized diphosphine ligand which is zwitterionic, the functional
group holding a 1,3-dithiol-2-ylidene iminium residue. This
is rather unusual and could be the starting point for preparing
even more sophisticated diphosphines, taking into account
that related organic iminium salts have been used for the
synthesis of tetrathiafulvalene-based organic conductors and
superconductors.18
Spectroscopic data in solution are in agreement with this
structure (see Table 1 and Experimental Section). Thus, the 31
P
NMR spectrum of 13a displayed two signals at 72.4 and 30.8
ppm, corresponding to two inequivalent phosphorus atoms. The
IR spectrum of this cationic complex showed only a moderate
increase in the frequency of the CO stretching bands with respect
to the neutral starting complex 11a, as a result of the zwitterionic
nature of the ligand, resulting from the positive charge being
situated mainly on the nitrogen atom of the dimethyliminium
group and the negative charge delocalized on the metallacycle.
All attempts to grow X-ray-quality crystals of 13a were
unsuccessful; therefore, the reaction was repeated employing
the parent tetracarbonyl complex [Mn(CO)4{(PPh2)2C-SC(S)-
NMe2}] (11b). Reaction of 11b with thiocyanogen proceeded
similarly to our previous result, yielding the complex 13b.
Spectroscopic features of this derivative are very similar to those
corresponding to 13a, indicating that the same type of reaction
had occurred. The structure of 13b was determined by X-ray
analysis (Figure 4). Bond lengths and angles within the
metallacycle are similar to those observed in 4 and 5 (Table 4).
A five-membered ring is fused to the metallacycle. This
dithiaheterocycle is essentially planar, in which all carbon-
sulfur bond distances are slightly smaller than those correspond-
Compound 12 also reacts instantly with 1 equiv of thiocy-
anogen, yielding a mixture from which the neutral derivative
14 was obtained after chromatographic workup (Scheme 5). The
31P NMR spectrum suggested a similar insertion process of the
thiocyanogen molecule into the P-C bond of the ligand, as it
showed two signals at 60.1 and 47.2 ppm. The IR spectrum is
very similar to that of compound 4, and a weak band corre-
1
sponding to a SCN group can be seen at 2142 cm-1. The H
NMR spectrum of 14 displayed signals characteristic of the
5-nitropyridine group. Confirmation of the structural formulation
was unambiguously established by X-ray structural diffraction
(Figure 5 and Table 5). Compound 14 crystallized jointly with
two molecules of dichloromethane. Structural parameters are
(18) (a) Dahlstedt, E.; Hellberg, J.; Petoral, R. M., Jr.; Uvdal, K. J. Mater.
Chem. 2004, 14, 81-85. (b) Cristau, H. J.; Darviche, F.; Babonneau, M.
T.; Fabre, J. M.; Torreilles, E. Tetrahedron 1999, 55, 13029-13036. (c)
Veciana, J.; Rovira, C.; Cowan, D. Tetrahedron Lett. 1988, 29, 3467-
3470. (d) Moore, D. J.; Bryce, M. R. Synthesis 1997, 407-409.

Rare Diphosphine and Tetraphosphine Ligands
Organometallics, Vol. 26, No. 7, 2007 1709
Scheme 6. Protonation Reactions of Compounds 13a,b and 14 To Afford 15a,b and 16, Respectivelya
a 13a and 15a, [Mn] ) [Mn(CNtBu)(CO)3]+; 13b and 15b, [Mn] ) [Mn(CO)4]+.
very similar to those found in the case of disulfide 4, in which
one mononuclear fragment is replaced by the organic nitropy-
ridine fragment. It is worth noting that the S1-C1 bond distance
(1.850(3) Å) is significantly longer than the S2-C51 bond
distance (1.777(3) Å), highlighting the weakness of the first
C-S bond. The S1-S2 bond distance (2.0339(11) Å) corre-
sponds to a single bond and is similar to the sulfur-sulfur bond
lengths found in 4 and 5.
Compound 14 could be considered an evolution product from
the intermediate species proposed in Scheme 5. Thus, the first
step of the reaction should be the insertion of the (SCN)2
molecule into the P-C bond of the original ligand. This would
lead to an unstable intermediate, similar to the other examples
we have shown. In this case, steric impedance would disfavor
the formation of polysulfide chains, leading to the observed
result, in which SCN and S(NC5H3NO2) have switched their
positions.
of the S-S bond of the thiocyanogen molecule. The complexes
obtained are very reactive and either undergo intermolecular
S-S coupling processes, yielding dinuclear complexes linked
through polysulfide chains of different lengths, or intramolecular
transposition and cyclization processes, giving rare functional-
ized diphosphinomethanide complexes.
The nitrogen atom inserted into the diphosphine ring can be
protonated reversibly by strong acids. In the case of the dinuclear
complexes 4 and 5 this protonation is sequential to give the
corresponding cationic (9, 10) and dicationic (7, 8) derivatives,
highlighting the existence of an electronic communication
through the polysulfide chain, as well as of a proton-transfer
process dependent on the sulfur chain length. The new diphos-
phine ligands could pave the way toward even more sophisti-
cated systems, as the presence of a 1,3-dithiol-2-ylidene iminium
group in 13a,b suggests.
Treatment of compounds 13a,b and 14 with HBF4 yielded
the corresponding cationic derivative 15a,b and 16, respectively
(Scheme 6). All spectroscopic data are closely related to those
displayed by the doubly protonated polysulfides 7 and 8. The
IR spectra in Nujol dispersion showed a band asignable to a
N-H group at 3201 and 3182 cm-1, respectively, reflecting
that the protonation takes place on the nitrogen atom of the
diphosphine ring, and the CO stretching bands in solution
correspond to a cationic derivative. The 31P NMR spectra
displayed similar changes upon protonation. The chemical shift
of the phosphorus atom bonded to the carbon atom is only lightly
affected, whereas the other signal, corresponding to the phos-
phorus atom bonded to the nitrogen atom, is shifted downfield
by approximately 30 ppm (Table 1).
To date, we have only observed insertion of thiocyanogen
into the P-C bond of coordinated diphosphinomethanides with
ligands containing the P2CS skeleton. Nevertheless, it is
expected that other C-functionalized diphosphinomethanide
complexes could exhibit behavior toward thiocyanogen similar
to that described in this paper, thus enhancing the synthetic
possibilities of these systems.
Experimental Section
General Considerations. All reactions were carried out under
nitrogen atmosphere using standard 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 spec-
trophotometers). Elemental analyses were performed on a Perkin-
Elmer 240B elemental analyzer. 1H, 13C, and 31P NMR spectra were
recorded using Bruker AC-300 and AC-200 instruments. Chemical
shifts are given in ppm relative to internal SiMe4 (1H) or external
85% H3PO4 (31P) references. FAB-MS spectra were provided by
the University of Santiago de Compostela Mass Spectrometry
Service. fac-[Mn(CNtBu)(CO)3{(PPh2)2CH}] (1),19 fac-[Mn(CNtBu)-
(CO)3{(PPh2)2CSCN}] (2),4 fac-[Mn(CNtBu)(CO)3{(PPh2)2CSC-
(S)NMe2}] (11a),17 and [Mn(CO)4{(PPh2)2CSC(S)NMe2}] (11b)17
were prepared as reported.
Compound 3. A solution containing (SCN)2 (0.027 g, 0.230
mmol) was added dropwise to a solution of 2 (0.15 g, 0.226 mmol)
with continuous stirring over 5 min at room temperature. The
solution was then concentrated to 2 mL under vacuum. The addition
of hexane (10 mL) produced the precipitation of a white solid; yield
85% (0.15 g). Data for 3 are as follows. IR (CH2Cl2): ν 2172 m
(CNtBu), 2147 w (SCN), 2030 vs, 1967 s cm-1 (CO). H NMR
1
(CD2Cl2): δ 7.96-7.04 (20H, Ph), 1.50 ppm (s, 9H, tBu). 31P-
{1H} NMR (CH2Cl2/D2O): δ 70.8 (br), 47.1 (br) ppm. FAB-MS
(positive ion): m/z 779 [M+], 753 [M+ - CN], 721 [M+ - SCN],
689 [M+ - SSCN]. Anal. Calcd for C36H29MnN4O3P2S3: C, 55.53;
H, 3.75; N, 7.19. Found: C, 54.58; H, 3.97; N, 6.92.
Conclusion
Reaction of thiocyanogen with coordinated diphosphi-
nomethanide ligands bearing different S-R functionalities
resulted in the insertion of the pseudohalogen molecule into a
P-C bond of the ligand. This process represents an unprec-
edented example of insertion into a rather strong P-C bond
which occurs instantly at room temperature, without breaking
(19) Ruiz, J.; Riera, V.; Vivanco, M.; Garc´ıa-Granda, S.; Garc´ıa-
Ferna´ndez, A. Organometallics 1992, 11, 4077-4082.

1710 Organometallics, Vol. 26, No. 7, 2007
Ruiz et al.
Compounds 4-6. Compound 3 (0.10 g, 0.128 mmol) was passed
through an alumina column (activity degree III). Elution with CH2-
Cl2/hexane (1:1) afforded 5 along with small amounts of 6; further
elution with CH2Cl2/hexane (3:2) afforded 4. Both fractions were
recrystallized in CH2Cl2/hexane to give 4 and 5 as colorless crystals.
A second recrystallization of the first fraction provided 6 as the
major product in the mother liquor. Data for 4 are as follows.
Yield: 30% (0.028 g). IR (CH2Cl2): ν 2173 m (CNtBu), 2142 w
(SCN), 2025 vs, 1961 s cm-1 (CO). 1H NMR (CD2Cl2): δ 8.70-
5.70 (40 H, Ph), 1.60 (s, 18 H, tBu). 31P{1H} NMR (CH2Cl2/
D2O): δ 61.1 (s, br), 47.2 (s, br). FAB-MS (positive ion): m/z
1441 [M+]. Anal. Calcd for C70H58Mn2N6O6P4S4: C, 58.33; H, 4.06;
N, 5.83. Found: C, 58.61; H, 4.17; N, 6.01. Data for 5 are as
follows. Yield: 20% (0.019 g). IR (CH2Cl2): ν 2174 m (CNtBu),
of 2,2′-dithiobis(5-nitropyridine) was added. The mixture turned
orange immediately. After 10 min of stirring the solvent was
removed and the oily solid that was obtained was chromatographed
through an Alox III column. An orange band was eluted using a
1:1 dichloromethane/hexane mixture, which was collected and the
solvent evaporated, giving the desired product as an orange solid.
Data for 12 are as follows. Yield: 40% (50 mg). IR (CH2Cl2): ν
1
2172 m (CNtBu), 2015 vs, 1952 s, 1934 s cm-1 (CO). H NMR
4
(CDCl3): δ 9.02 (d, JHH ) 3 Hz, Hc), 7.74-7.15 (21 H, Ph +
3
Hb), 6.89 (d, JHH ) 9 Hz, Ha), 0.77 (s, 9 H, tBu). 31P{1H} NMR
(CDCl3): δ 23.2 (s). Anal. Calcd for C34H23MnN2O6P2S: C, 60.08;
H, 4.25; N, 5.53. Found: C, 60.22; H, 4.36; N, 5.68.
Compound 13a. A solution containing (SCN)2 (0.014 g, 0.138
mmol) was added dropwise to a solution of 11 (0.10 g, 0.138 mmol)
in 10 mL of CH2Cl2 with continuous stirring over 5 min at room
temperature. The solvent was removed under vacuum and the
obtained solid purified by column chromatography. Small amounts
of starting material were eluted using 50 mL of dichloromethane,
and then a brown band was eluted using a MeOH/CH2Cl2 (1:10)
mixture. The brown solid obtained after evaporation of solvents
could be recrystallized by diffusion of ether into a dichloromethane
solution of the complex. Data for 13a are as follows. Yield: 55%
(60 mg). IR (CH2Cl2): ν 2172 m (CNtBu), 2055 w, 2034 vs, 1972
s cm-1 (CO). 1H NMR (CDCl3): δ 7.87-7.28 (20 H, Ph), 1.47 (s,
9 H, tBu). 31P{1H} NMR (CDCl3): δ 74.2 (d, 2JPP ) 61 Hz, PPh2),
30.8 (d, 2JPP ) 61 Hz, PPh2). Anal. Calcd for C38H35MnN4O4P2S2:
C, 57.57; H, 4.45; N, 7.07. Found: C, 57.34; H, 4.31; N, 7.10.
1
2142 w (SCN), 2026 vs, 1963 s cm-1 (CO). H NMR (CD2Cl2):
δ 8.19-6.97 (40 H, Ph), 1.57 (s, 18 H, tBu). 31P{1H} NMR (CH2-
Cl2/D2O): δ 64.6 (s, br), 47.4 (s, br). FAB-MS (positive ion): m/z
1473 [M+]. Anal. Calcd for C70H58Mn2N6O6P4S5: C, 57.06; H, 3.97;
N, 5.70. Found: C, 56.85; H, 4.05; N 5.98. Data for 6 are as follows.
IR (CH2Cl2): ν 2174 m (CNtBu), 2142 w (SCN), 2026 vs, 1963 s
cm-1 (CO). 31P{1H} NMR (CH2Cl2/D2O): δ 67.6 (s, br), 47.5 (s,
br). FAB-MS (positive ion): m/z 1505 [M+].
Compound 7. A 50 mg portion (0.035 mmol) of compound 4
was dissolved in 10 mL of dichloromethane, and to this solution
12 µL (0.087 mmol) of HBF4 (54% diethyl ether complex) was
added with stirring. The volume was then reduced to 2 mL, and
addition of 10 mL of diethyl ether produced the precipitation of a
yellow solid, which was washed with diethyl ether (2 × 5 mL)
and dried. Data for 7 are as follows. Yield: 90% (51 mg). IR (CH2-
Cl2): ν 2176 m (CNtBu), 2053 vs, 2000 s, 1969 m cm-1 (CO). 1H
NMR (CD2Cl2): δ 7.90-7.26 (42 H, Ph + 2 × NH), 1.28 (s, 18
H, tBu). 31P{1H} NMR (CH2Cl2/D2O): δ 107.8 (d, 2JPP ) 67 Hz),
55.2 (d, 2JPP ) 67 Hz). Anal. Calcd for C70H60B2F8Mn2N6O6P4S4:
C, 52.00; H, 3.74; N, 5.20. Found: C, 51.62; H, 3.93; N, 5.39.
Compound 13b. This compound was prepared as above, using
0.10 g (0.149 mmol) of [Mn(CO)4{(PPh2)2C-SC(S)NMe2}] (11b)
and 0.015 g (0.15 mmol) of thiocyanogen. Yield: 55% (62 mg).
X-ray-quality crystals were growth by slow diffusion of diethyl
ether into a dichloromethane solution of the complex. Data for 13b
are as follows. IR (CH2Cl2): ν 2084 s, 2057 w, 2021 m, 2000 vs
1
cm-1 (CO). H NMR (CDCl3): δ 7.85-6.90 (m, 20 H, Ph). 13C-
Compound 8. This compound was prepared as detailed above;
9 µL (0.065 mmol) of HBF4 (54% diethyl ether complex) was added
to 40 mg (0.027 mmol) of 5 dissolved in 10 mL of dichloromethane.
Data for 8 are as follows. Yield: 90% (51 mg). Anal. Calcd for
C70H60B2F8Mn2N6O6P4S5: C, 50.99; H, 3.67; N, 5.10. Found: C,
51.17; H, 3.78; N, 5.30. IR (CH2Cl2): ν 2175 m (CNtBu), 2053
{1H} NMR (CH2Cl2/D2O): δ 213.4 (a, CO), 212.0 (a, CO), 182.1
(s, S2CNMe2), 172.3 (a, NCCP), 138.6-130.0 (Ph), 76.4 (dd, 1JPC
3
) 49 Hz, JPC ) 17 Hz, PCCN), 50.5 (a, CH3), 47.9 (a, CH3).
31P{1H} NMR (CDCl3): δ 66.0 (s, a, PPh2), 25.7 (s, a, PPh2). Anal.
Calcd for C34H26MnN3O5P2S2: C, 55.36; H, 3.55; N, 5.70. Found:
C, 55.44; H, 3.67; N, 5.81.
vs, 1998 s, 1969 m cm-1 (CO). IR (Nujol dispersion): 3204 (νN-H
)
1
cm-1. H NMR (CD2Cl2): δ 7.80-7.01 (42 H, Ph + 2 × NH),
1.34 (s, 18 H, tBu). 31P{1H} NMR (CH2Cl2/D2O): δ 107.8 (s, br),
55.2 (s, br).
Compound 14. A solution containing (SCN)2 (0.013 g, 0.132
mmol) was added dropwise to a solution of 12 (0.10 g, 0.132 mmol)
in 10 mL of CH2Cl2 with continuous stirring over 5 min at room
temperature. A yellow band was eluted using a hexane/CH2Cl2 (1:
1.5) mixture. The yellow solid obtained after evaporation of solvents
can be recrystallized by diffusion of hexane into a dichloromethane
solution of the complex. Data for 14 are as follows. Yield: 20%
(0.023 g). IR (CH2Cl2): ν 2172 m (CNtBu), 2142 w (SCN), 2029
vs, 1966 s cm-1 (CO). 1H NMR (CDCl3): δ 9.14 (d, 4JHH ) 2 Hz,
Compound 9. A 3 µL portion (0.022 mmol) of HBF4 (54%
diethyl ether complex) was added to 30 mg (0.021 mmol) of 4
dissolved in 10 mL of dichloromethane. Evaporation of solvents
yielded a colorless oi, which could be precipitated as a white solid
from a CH2Cl2/hexane mixture. Data for 9 are as follows. Yield:
90% (29 mg). IR (CH2Cl2): ν 2172 m (CNtBu), 2143 w, 2051 vs,
2033 vs, 1996 s, 1973 s cm-1 (CO). IR (Nujol dispersion): 3174
(νN-H) cm-1. 1H NMR (CD2Cl2): δ 7.96-6.64 (41 H, Ph + NH),
1.55 (s, 18 H, tBu). 31P{1H} NMR (CH2Cl2/D2O): δ 87.7 (s, br),
51.9 (s, br). Anal. Calcd for C70H59BF4Mn2N6O6P4S4: C, 54.98;
H, 3.89; N, 5.50. Found: C, 54.71; H, 4.05; N, 5.65.
3
4
Hc), 8.09 (dd, JHH ) 9 Hz, JHH ) 2 Hz, Hb), 7.87-7.28 (21 H,
Ha + Ph), 1.48 (s, 9 H, tBu). 31P{1H} NMR (CDCl3): δ 69.1 (s,
br, PPh2), 47.2 (s, br, PPh2). Anal. Calcd for C40H32MnN5O5P2S3:
C, 54.86; H, 3.68; N, 8.00. Found: C, 54.74; H, 3.67; N, 8.10.
Compound 15a. A 9 µL portion (0.066 mmol) of HBF4 (54%
diethyl ether complex) was added to 40 mg (0.05 mmol) of 13a
dissolved in 10 mL of dichloromethane. Evaporation of solvents
yielded a colorless oil which was washed with diethyl ether (3 ×
5 mL), giving a yellow solid which could be recrystallized from a
dichloromethane/diethyl ether mixture. Data for 15a are as follows.
Yield: 85% (40 mg). IR (CH2Cl2): ν 2178 m (CNtBu), 2052 vs,
Compound 10. This compound was prepared as above, starting
with 30 mg (0.02 mmol) of compound 5 and 3 µL (0.022 mmol)
of HBF4 (54% diethyl ether complex). Data for 10 are as follows.
Yield: 90% (29 mg). IR (CH2Cl2): ν 2173 m (CNtBu), 2143 w,
2052 vs, 2032 vs, 1994 s, 1972 s cm-1 (CO). IR (Nujol disper-
sion): 3175 (νN-H) cm-1. 1H NMR (CD2Cl2): δ 7.96-6.64 (41H,
Ph + NH), 1.55 (s, 18H, tBu). 31P{1H} NMR (CH2Cl2/D2O): δ
103.0 (s, br), 73.4 (s, br), 52.4 (s, br), 47.7 (s, br). Anal. Calcd for
C70H59BF4Mn2N6O6P4S5: C, 53.85; H, 3.81; N, 5.38. Found: C,
53.53; H, 4.17; N, 5.40.
1
1990 s cm-1 (CO). IR (Nujol dispersion): 3201 (νN-H) cm-1. H
NMR (CD2Cl2): δ 7.70-7.21 (41 H, Ph + N-H), 1.61 (s, 9 H,
2
tBu). 31P{1H} NMR (CH2Cl2/D2O): δ 101.3 (d, JPP ) 62 Hz,
2
PPh2), 34.0 (d, JPP ) 62 Hz, PPh2). Anal. Calcd for C38H36BF4-
MnN4O4P2S2: C, 51.83; H, 4.12; N, 6.36. Found: C, 51.69; H,
4.20; N, 6.41.
Compound 12. A 100 mg portion (0.165 mmol) of 1 was
dissolved in 15 mL of dichloromethane, and 31 mg (0.10 mmol)

Rare Diphosphine and Tetraphosphine Ligands
Organometallics, Vol. 26, No. 7, 2007 1711
Compound 15b. This compound was prepared similarly to 15a,
using 40 mg (0.054 mmol) of 13b and 9 µL (0.066 mmol) of HBF4
(54% diethyl ether complex). Data for 15b are as follows. Yield:
85% (38 mg). IR (CH2Cl2): ν 2100 m, 2041 m, 2017 vs, 1985 s
the oscillation method, with a scan oscillation angle of 2.0° and 60
s exposure time per frame. The data collection strategy was
calculated with the program Collect.21 Structures were solved by
Patterson methods using DirDif;22 isotropic least-squares refine-
ments on F2 were made using SHELXL-97;23 during the final stages
of refinements on F2 the positional parameters and the anisotropic
thermal parameters of the non-H atoms were refined. Figures 1, 2,
4, and 5 were made with ORTEP,24 showing the atomic numbering
schemes. Atomic scattering factors were taken from ref 25.
Geometrical calculations were made with PARST.26
1
cm-1 (CO). H NMR (CDCl3): δ 7.75-7.23 (41 H, Ph + NH).
31P{1H} NMR (CDCl3): δ 98.5 (br), 30.0 (br). Anal. Calcd for
C34H27BF4MnN3O5P2S2: C, 49.47; H, 3.30; N, 5.09. Found: C,
49.57; H, 3.21; N, 5.20.
Compound 16. This compound was prepared as detailed above,
starting with 30 mg (0.034 mmol) of compound 14 and 6 µL (0.044
mmol) of HBF4. Data for 16 are as follows. Yield: 85% (28 mg).
IR (CH2Cl2): ν 2173 m (CNtBu), 2052 vs, 1997 s cm-1 (CO). IR
(Nujol dispersion): 3182 (νN-H) cm-1. 1H NMR (CDCl3): δ 9.26
Acknowledgment. This work was supported by the Spanish
Ministerio de Ciencia y Tecnolog´ıa (PGE and FEDER funding,
Project BQU2003-01011). R.Q. thanks the Ministerio de Edu-
cacio´n y Ciencia for a contract (Programa Juan de la Cierva).
3
4
3
(a, Hc), 8.54 (dd, JHH ) 8 Hz, JHH ) 2 Hz, Hb), 8.06 (d, JHH
)
8 Hz, Ha), 7.67-7.16 (20 H, Ph), 1.61 (s, 9 H, tBu). 31P{1H} NMR
(CDCl3): δ 101.3 (d, 2JPP ) 88 Hz, PPh2), 51.6 (d, 2JPP ) 88 Hz,
PPh2). Anal. Calcd for C40H32BF4MnN5O5P2S3: C, 49.91; H, 3.45;
N, 7.27. Found: C, 50.01; H, 3.52; N, 7.38.
Supporting Information Available: CIF files giving crystal-
lographic data for 4, 5, 13b, and 14. This material is available free
of charge via the Internet at http://pubs.acs.org.
X-ray Crystallography. Crystallographic data for 4, 5, 13b, and
14 are summarized in Table 6. A colorless (4, 5) or yellow (13b,
14) prismatic crystal was selected for each experiment. Throughout
the experiment Cu KR radiation was used with a graphite crystal
monochromator on a Nonius Kappa-CCD (λ ) 1.541 84 Å) single-
crystal diffractometer. Unit cell dimensions were determined from
the angular settings of a high number of reflections with θ between
3.0 and 70.0° and refined with the programs HKL Denzo and
Scalepack.20 Space groups were determined to be, in all cases,
triclinic P1h, from the structure determination. The crystal-detector
distance was fixed at 29 mm, and the images were collected using
OM0611195
(21) Nonius, B. V. Collect; Nonius BV, 1997-2000.
(22) Beurskens, P. T.; Beurskens, G.; de Gelder, R.; Garc´ıa-Granda, S.;
Gould, R. O.; Israel, R.; Smits, J. M. M. The DIRDIF-99 Program System;
Technical Report of the Crystallography Laboratory, University of Nijmegen,
Nijmegen, The Netherlands, 1999.
(23) Sheldrick, G. M. SHELXL97: Program for Crystal Structure
Refinement; University of Go¨ttingen, Go¨ttingen, Germany, 1997.
(24) Farrugia, L. J. ORTEP3 for Windows. J. Appl. Crystallogr. 1997,
30, 565.
(25) International Tables for Crystallography; Kynoch Press: Birming-
ham, U.K., 1992 (present distributor Kluwer Academic Publishers, Dor-
drecht, The Netherlands); Vol. C, Tables 4.2.6.8 and 6.1.1.4.
(26) Nardelli, M. J. Appl. Crystallogr. 1995, 28, 659.
(20) Otwinowski, Z.; Minor, W. Methods Enzymol. 1997, 276, 307-
326.