Dithiocarbamyl-substituted diphosphanylmethanide complexes of manganese(I): A new type of ambivalent metalloligands

Article abstract of DOI:10.1039/b305045a

The diphosphanylmethanide complex [Mn(CO)₄{(PPh ₂)₂C-H}] promotes S-S bond breaking in tetramethylthiuram disulfide affording [Mn(CO)₄{(PPh₂) ₂C-S-C(S)NMe₂}] (2), which proved to be a valuable host for binding cations through the methanide carbon atom and the thiocarbonyl group, allowing the controlled synthesis of heterometallic compounds.

Full text of DOI:10.1039/b305045a

Dithiocarbamyl-substituted diphosphanylmethanide complexes of
manganese( ): a new type of ambivalent metalloligands
I
Javier Ruiz,*a Roberto Quesada,a Víctor Riera,a Santiago García-Grandab and M. Rosario Díazb
a Departamento de Química Orgánica e Inorgánica, Facultad de Química, Universidad de Oviedo, 33071
Oviedo, Spain. E-mail: jruiz@sauron.quimica.uniovi.es; Fax: (+34) 985103446
b Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33071
Oviedo, Spain
Received (in Cambridge, UK) 7th May 2003, Accepted 19th June 2003
First published as an Advance Article on the web 3rd July 2003
The diphosphanylmethanide complex [Mn(CO)4{(PPh2)2C–
H}] promotes S–S bond breaking in tetramethylthiuram
disulfide affording [Mn(CO)4{(PPh2)2C–S–C(S)NMe2}] (2),
which proved to be a valuable host for binding cations
through the methanide carbon atom and the thiocarbonyl
group, allowing the controlled synthesis of heterometallic
compounds.
Metalloligands are useful species for the rational design of
heterometallic complexes. Most known S-donor metalloligands
contain simple thiolate groups1 or polythioether macrocycles,2
and they show not only suitability for the synthesis of
Fig. 1 ORTEP drawing of 2 (A) and 4 (B); hydrogen atoms are omitted for
clarity. Selected bond distances [Å] and angles [°]: 2: P(1)–C(1) 1.740(4),
P(2)–C(1) 1.749(4), C(1)–S(1) 1.740(3), S(1)–C(2) 1.804(3), C(2)–S(2)
1.650(3), C(2)–N(1) 1.322(4); P(1)–C(1)–P(2) 100.79(17), C(1)–S(1)–C(2)
110.02(16). 4: P(1)–C(1) 1.799(3), P(2)–C(1) 1.806(3), C(1)–S(1) 1.766(3),
S(1)–C(2) 1.785(4), C(2)–S(2) 1.690(4), C(2)–N(1) 1.326(4), C(1)–Cu(1)
2.095(3), S(2)–Cu(1) 2.2317(9); P(1)–C(1)–P(2) 97.45(15), C(1)–S(1)–
C(2) 108.91(16), C(1)–Cu(1)–S(2) 98.78, C(1)–Cu(1)–N(2) 138.91(12),
S(2)–Cu(1)–N(2) 122.0(9).
heterometallic compounds but also promise for attractive
potential applications, such as redox-responsive sensors for the
binding of late metals and encapsulation.3 Most of these S-
donor metalloligands display no other donor atom apart from
sulfur. In relation to this, we describe here a new approach for
the controlled synthesis of heterometallic complexes by prepar-
ing a dithiocarbamyl-substituted diphosphanylmethanide man-
ganese( complex, namely [Mn(CO)4{(PPh2)2C–S–
I)
C(S)NMe2}] (2), which behaves as an ambivalent C- and
S-donor metalloligand through the methanide carbon atom and
the sulfur atom from the thiocarbonyl unit.4†
plane), so that the structure clearly shows the availability of the
C(1) and S(2) donor atoms to trap cations in a chelating manner.
One example could be considered the proton itself giving the
above-mentioned complex 3. In the 1H NMR spectrum of 3 the
resonance of the P2CH hydrogen is noteworthy, consisting of a
triplet (2JPH = 13 Hz) strongly shifted down field (d 8.53).
Considering that in most known C-functionalized bis(diphenyl-
phosphino)methane ligands this signal appears in the range of
5.5–6.5 ppm,7 the existence of a intramolecular C–H…S
hydrogen bond in 3 completing a pseudo five-membered
heterocycle seems very likely.
Soft late metal ions are good candidates to be coordinated by
metalloligand 2. Thus, reaction of 2 with [Cu(NCMe)4]BF4
afforded, after a few minutes of stirring at room temperature, the
heterometallic complex 4 (Scheme 2). The appreciable increase
in the frequencies of the n(CO) bands in the IR spectrum of 4
(2084, 2017, 2001, 1987 cm21) with respect to 2 (2074, 1996,
Reaction of [Mn(CO)4{(PPh2)2C–H}] (1)5 with one equiva-
lent of tetramethylthiuram disulfide (TMTD) in refluxing
toluene produces a yellow solution of 2. Crystals of 2 were
obtained from CH2Cl2–hexane solutions in 70% yield, and were
fully characterized, including a solid structure determination by
X-ray analysis. As shown in Scheme 1, a mechanism can be
proposed for this reaction involving heterolytic cleavage of the
S–S bond6 in TMTD affording the intermediate cationic
complex 3 and dimethyldithiocarbamate anion, which further
deprotonates 3 to give neutral 2. In fact, independent experi-
ments show that 2 can be easily protonated by HBF4 producing
stable 3, and that this is readily deprotonated by treatment with
sodium dimethyldithiocarbamate affording 2. The structure of 2
(Fig. 1 (A)) shows the presence of the new dithiocarbamyldi-
phosphanylmethanide ligand bonded through the phosphorus
atoms to manganese, completing with the four carbonyl groups
the octahedral coordination around this metal ion.‡ The planes
C(1)–S(1)–C(2)–S(2) and P(1)–C(1)–P(2) are roughly orthogo-
nal to each other and the carbon atom C(1) makes the P(1)–
P(2)–C(1)–S(1) skeleton slightly pyramidal toward the S(2)
atom (the C(1) atom lies 0.19 Å out of the P(1)–S(1)–P(2)
Scheme 1 Synthesis of complex 2. [Mn] = Mn(CO)4.
Scheme 2 Synthesis of complexes 4 and 5. [Mn] = Mn(CO)4.
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1963 cm21) gives a first indication that coordination through
the methanide carbon atom has taken place. Apart from two
methyl resonances corresponding to the dimethyldithiocarba-
with pH dependent translocation of metal ions, a subject of great
interest in supramolecular chemistry.8
This work was supported by the Spanish Ministerio de
Ciencia y Tecnología (Project BQU2000-0220) and by the
Principado de Asturias (Project PR-01-GE-7).
1
myl substituent (d 3.49 and 3.57), the H NMR spectrum of 4
shows a methyl signal (d 1.86) in a zone indicative of
coordinated acetonitrile. The structure of complex 4 was
definitively established by X-ray crystallography. As shown in
Fig. 1 (B) this complex displays a [Cu(NCMe)]+ fragment
bonded to C(1) and S(2) atoms to form a spirocyclic
heterodimetallic cation. The five membered metallacycle C(1)–
S(1)–C(2)–S(2)–Cu(1) is planar and orthogonal to the plane
P(1)–C(1)–P(2). As expected, the P(1)–C(1) (1.799(3) Å) and
P(2)–C(1) (1.806(3) Å) distances are longer than the corre-
sponding distances in 2 (1.740(4) Å and 1.749(4) Å, re-
spectively), as well as the C(2)–S(2) bond length (1.690(4) Å in
4 and 1.650(3) Å in 2), owing to electron donation from C(1)
Notes and references
† Selected spectroscopic data for 2: IR (CH2Cl2), n(CO)
= 2074(s),
1996(vs), 1963(s) cm21; H NMR (300 MHz, CD2Cl2): d = 3.30 (s, 6H,
Me), 7.34–7.78 (20H, Ph); 31P{1H} NMR (121.5 MHz, CD2Cl2): d = 20.0
(br). 3: IR (CH2Cl2), n(CO) = 2093(s), 2034(m), 2012(vs) cm21; 1H NMR
(300 MHz, CD2Cl2): d = 3.34 (s, 3H, Me), 3.46 (s, 3H, Me), 7.47–7.63
(20H, Ph), 8.53 (t, 1H, P2CH); 31P{1H} NMR (121.5 MHz, CD2Cl2): d =
48.4 (br). 4: IR (CH2Cl2), n(CO) = 2084(s), 2017(s), 2001(vs), 1987(s)
1
cm21 1H NMR (300 MHz, CD2Cl2): d = 1.86 (s, 3H, Me), 3.49 (s, 3H,
;
Me), 3.57 (s, 3H, Me), 7.48–7.70 (20H, Ph); 31P{1H} NMR (121.5 MHz,
CD2Cl2): d = 35.5 (br). 5: IR (CH2Cl2), n(CO) = 2093(s), 2034(m),
2012(vs) cm21; 1H NMR (300 MHz, CD2Cl2): d = 3.42 (s, 3H, Me), 3.55
(s, 3H, Me), 7.49–7.68 (20H, Ph), 8.26 (t, 1H, P2CH); 31P{1H} NMR (121.5
MHz, CD2Cl2): d = 47.8 (br).
and S(2) donor atoms to Cu( ).
I
The donor capability of 2 through the methanide carbon atom
is disrupted on protonation, forming complex 3, where the
coordination ability is confined to the thiocarbonyl residue.
Thus, treatment of 3 with half an equivalent of [Cu(NC-
Me)4]BF4 afforded the trimetallic cationic complex 5, which
displays n(CO) bands in the IR spectrum at exactly the same
frequencies than those of 3, indicating that changes in the
molecule have occurred far away from manganese. The P2CH
triplet in 1H NMR spectrum of 5 has slightly changed (d 8.26,
2JPH = 12 Hz) with respect to 3, but still appears at very high
chemical shift showing that the C–H…S hydrogen bond still
remains after coordination of the sulfur atom involved in such
interactions. As we were unable to obtain suitable crystals of 5
for X-ray analysis, we prepared, by using the same synthetic
approach as that for 5, the very similar derivative fac-[Mn(CN-
t-Bu)(CO)3{(PPh2)2C(H)SC(S)NMe2}]2Cu]3+ (5a), in which a
carbonyl ligand has been substituted by CN-t-Bu. The structure
of 5a (Fig. 2) shows the copper atom bridging two units of the
manganese complex 3 through the thiocarbonyl sulfur atoms in
a linear coordination mode. The structural data confirm the
presence of two C–H…S hydrogen bonds, as the S(2)–H(1)
distance of 2.55(5) Å is clearly shorter than the sum of van der
Waals radii of those atoms (3.15 Å).
‡
Crystal data for 2 (C32H26MnNO4P2S2): M = 669.54, crystal size 0.33
3 0.20 3 0.13 mm, a = 10.5648(7), b = 11.6965(6), c = 15.042(1) Å, a
= 95.264(5), b = 104.315(4), g = 115.24(4)°, V = 1587.3(6) Å3, rcalcd
=
¯
1.401 g cm23, m = 0.685 mm21, Z = 2, triclinic, space group P1, l =
0.71073 Å, T = 293(2) K, qmax = 25.98, independent reflections = 5620,
refined parameters = 474, R1 = 0.0397, wR2 = 0.0902, largest diff. peak
and hole 0.259 and 20.231 e Å23. CCDC 210265.
Crystal data for 4 ((C34H29CuMnN2O4P2S2)(BF4).2(CH2Cl2)): M
=
1030.79, crystal size 0.35 3 0.23 3 0.18 mm, a = 10.3689(1), b =
12.9100(2), c = 16.8117(2) Å, a = 101.757(1), b = 99.022(1), g =
93.981(1)°, V = 2163.99(5) Å3, rcalcd = 1.582 g cm23, m = 7.355 mm21
,
¯
Z = 2, triclinic, space group P1, l = 1.5418 Å, T = 293(2) K, qmax
=
68.61, independent reflections = 7930, refined parameters = 638, R1 =
0.0546, wR2 = 0.1427, largest diff. peak and hole 1.151 and 20.799 e Å23
.
CCDC 210266.
Crystal data for 5a ((C72H72CuMn2N4O6P4S4)3(BF4).2(CH2Cl2)): M =
1945.16, crystal size 0.08 3 0.05 3 0.03 mm, a = 11.1163(3), b =
19.3279(8), c
= 21.773(1) Å, a = 69.660(3), b = 79.268(3), g =
84.282(2)°, V = 4306.5(3) Å3, rcalcd = 1.500 g cm23, m = 6.054 mm21
,
¯
Z = 2, triclinic, space group P1, l = 1.5418 Å, T = 293(2) K, qmax
=
68.35, independent reflections = 15758, refined parameters = 1224, R1 =
0.0560, wR2 = 0.1375, largest diff. peak near to the solvent region and hole
2.170 and 20.893 e Å23. CCDC 210267.
See http://www.rsc.org/suppdata/cc/b3/b305045a/ for crystallographic
data in .cif format.
The formation of 5 or 4 depending on whether the
metalloligand 2 is protonated or not on the methanide carbon
atom, and containing either linear or trigonal coordinated
copper( ), respectively, suggests some relation of these species
I
1 D. W. Stephan, Coord. Chem. Rev., 1989, 95, 41; D. W. Stephan, Coord.
Chem. Rev., 1996, 147, 147; T. Konno, Y. Chikamoto, K. Okamoto, T.
Yamaguchi, T. Ito and M. Hirotsu, Angew. Chem., Int. Ed., 2000, 39,
4098; I. Ara, S. Delgado, J. Forniés, E. Hernández, E. Lalinde, N.
Mansilla and M. T. Moreno, J. Chem. Soc., Dalton Trans., 1996, 3201;
M. Zhou, Y. Xu, C. Lam, L. Koh, K. F. Mok, P. Leung and T. S. A. Hor,
Inorg. Chem., 1993, 32, 4660; T. T. Nadasdi and D. W. Stephan, Inorg.
Chem., 1994, 33, 1532.
2 S. L. Ingham and N. J. Long, Angew. Chem., Int. Ed. Engl., 1994, 33,
1752; T. T. Nadasdi and D. W. Stephan, Organometallics, 1992, 11,
116.
3 Y. Huang, R. J. Drake and D. W. Stephan, Inorg. Chem., 1993, 32, 3022
and refs therein.
4 The use of 1,1A-bis(diethyldithiocarbamyl)ferrocene as metalloligand has
been described: M. C. Gimeno, P. G. Jones, A. Laguna, C. Sarroca, M. J.
Calhorda and L. F. Veiros, Chem. Eur. J., 1998, 4, 2308; O. Crespo, M.
C. Gimeno, P. G. Jones, A. Laguna and C. Sarroca, Chem. Commun.,
1998, 1481.
5 J. Ruiz, V. Riera, M. Vivanco, S. García-Granda and A. García-
Fernández, Organometallics, 1992, 11, 4077.
6 For S–S bond cleavage in TMTD by Grignard and organolithium
reagents see: J. R. Grunwell, J. Org. Chem., 1970, 35, 1500 and reference
4.
7 J. Ruiz, V. Riera, M. Vivanco, S. García-Granda and M. R. Díaz,
Organometallics, 1998, 17, 4562.
Fig. 2 ORTEP drawing of 5a; hydrogen atoms, except those involved in
hydrogen bonds, are omitted for clarity. Selected bond distances [Å] and
angles [°]: P(1)–C(1) 1.888(4), P(2)–C(1) 1.863(4), C(1)–S(1) 1.791(4),
S(1)–C(2) 1.771(4), C(2)–S(2) 1.714(4), S(2)–Cu(1) 2.1639; P(1)–C(1)–
P(2) 94.35(18), C(1)–S(1)–C(2) 104.37(18).
8 V. Amendola, L. Fabbrizzi, M. Licchelli, C. Mangano, P. Pallavicini, L.
Parodi and A. Poggi, Coord. Chem. Rev., 1999, 190–192, 649.
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