Sulfur-assisted chloride and triphenylphosphine dissociation of palladium(II) complex [Pd(PPh3)2(η1-SCNMe2)(Cl)]. X-ray structures of [Pd(PPh3)2(η1-SCNMe2)(Cl)], [Pd(PPh3)(Cl)]2(μ,η2-SCNMe2)2, and [Pd(PPh3)2(η2-SCNMe2)][PF6]

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Sulfur-assisted chloride and triphenylphosphine dissociation

of palladium(II) complex [Pd(PPh

3

)

2

(g

1

-SCNMe

2

)(Cl)]. X-ray

structures of [Pd(PPh

3

)

2

(g

1

-SCNMe

2

)(Cl)], [Pd(PPh

3

)(Cl)]

2

(l; g

2

-SCNMe

2

)

2

, and [Pd(PPh

3

)

2

(g

2

-SCNMe

2

)][PF

6

]

Kuang-Hway Yih

a,*

, Gene-Hsiang Lee

b

, Yu Wang

c

a

Department of Applied Cosmetology, Hung Kuang University, Shalu, Taichung, Taiwan 433, Republic of China

b

Instrumentation Center, College of Science, National Taiwan University, Taiwan, Republic of China

c

Department of Chemistry, National Taiwan University, Taiwan 106, Republic of China Received 22 November 2002; accepted 25 January 2003

Abstract

Treatment of PdðPPh

3

Þ

4

with Me

2

NCð@SÞCl in dichloromethane at )20 °C produces the complex ½PdðPPh

3

Þ

2

ðg

1

-SCNMe

2

Þ

ðClÞ, 2. Variable temperature

1

_{H and}

31

_{P{H} NMR experiments of complex 2 shows the dissociation of either the chloride or the}

triphenylphosphine ligand to form complex

½PdðPPh

3

Þ

2

ðg

2

-SCNMe

2

Þ½Cl, 3 or the dipalladium complex ½PdðPPh

3

ÞCl

2

ðl; g

2

-SCNMe

2

Þ

2

, 4. The reaction of complex 2 with NaPF

6

aﬀords complex

½PdðPPh

3

Þ

2

ðg

2

-SCNMe

2

Þ½PF

6

, 5. Complexes 2, 4, and 5 are

characterized by X-ray diﬀraction analyses.

Ó 2003 Elsevier Science B.V. All rights reserved.

Keywords: Dissociation behaviour; N,N-dimethylthiocarbamoyl; Palladium; Sulfur-assisted; X-ray diﬀraction

The study of transition-metal compounds containing

the N,N-dialkylthiocarbamonyl ligand (

SCNR

2

) is of

interest in that this ligand may behave like a mono- or

bidentate in ether, resulting in novel structural and

chemical features [1]. We have recently been

investigat-ing the chemistry of sulfur-containinvestigat-ing heteroallenes and

related molecules with mono- and binuclear systems in

order to obtain a better understanding of how these

molecules interact with the metal center [2]. In this

pa-per, we report the preparation and properties of

palla-dium complexes with the

SCNMe

2

containing ligand.

Treatment of PdðPPh

3

Þ

4

, 1 with Me

2

NCð@SÞCl in

dichloromethane at

)20 °C yields the yellow complex

[PdðPPh

3

Þ

2

ðg

1

-SCNMe

2

ÞðClÞ], 2 (Scheme 1). The

vari-able temperature

1

H and

31

P{

1

H} NMR spectra of 2

show three sets of methyl resonances of SCNMe

2

and

three sets of triphenylphosphine resonances at 233 K in

CDCl

3

. As depicted in Fig. 1, the three sets of

reso-nances are assigned to the 2 and the dissociation of

ei-ther the chloride of 2 to form the mononuclear complex

½PdðPPh

3

Þ

2

ðg

2

-SCNMe

2

Þ½Cl, 3 or the

triphenylphos-phine ligand of 2 to form the dipalladium complex

½PdðPPh

3

ÞCl

2

ðl; g

2

-SCNMe

2

Þ

2

, 4. Continuous stirring

dichloromethane solution of complex 2 at room

tem-perature for 8 h produces complex 4 as the ultimate

product. The spectroscopic [3]and analytical data of 2–4

are obtained. Complex [PdðPPh

3

Þ

2

ðg

1

-CH

2

SCH

3

ÞCl]

[4a]is the one only reported example including the

dis-sociation observation to form monomer complexes

[PdðPPh

3

Þðg

2

-CH

2

SCH

3

ÞCl]and [PdðPPh

3

Þ

2

ðg

2

-CH

2

SCH

3

Þ½Cl]. From the above description, one can

con-clude that the sulfur atom of SCNMe

2

ligand assists

triphenylphosphine or chloride dissociation of 2 to form

4 or 3.

The dissociation of the chloride ligand from 2 also

can be conﬁrmed by the shorter reaction time of 2 with

Inorganic Chemistry Communications 6 (2003) 577–580

www.elsevier.com/locate/inoche

*

Corresponding author. Fax: +886-4-26321046. E-mail address:[email protected](K.-H. Yih).

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NaPF

6

in acetone at room temperature to form complex

½PdðPPh

3

Þ

2

ðg

2

-SCNMe

2

Þ½PF

6

, 5 (5 min) than those of

chloride abstraction reaction of complex [C

6

H

4

CH

2

NMe

2

)Pd(Cl)(2,6-dimethoxyphenyl)diphenylphosphine]

[4b]with NaPF

6

(3 h) and [PdðPPh

3

Þ

2

ðCH

2

SCH

3

ÞCl]

with NH

4

PF

6

(15 min) in the same reactive conditions.

The spectroscopic [5]and analytical data of 5 are in

good agreement with the formulation. The

1

_{H and}

31

_P{

1

_{H} NMR spectra of 5 are similar to those of 3. In}

the

1

_{H NMR spectrum of 5, the two methyl protons of}

the SCNMe

2

ligand exhibit two resonances at d 2.54 and

d

3.61. The corresponding

13

_C{

1

_{H} NMR signals are at}

d

45.9 and d 53.9. The

31

_P{

1

_{H} NMR spectrum of 5}

shows two doublet resonances at d 23.1 and d 35.1 due

to the chemical inequivalence of the two PPh

3

ligands

and the relative downﬁeld resonance than that of 2 (d

16.6) which shows the cationic character of 5. From the

description, it is clear that the palladium of 5 is side-on

bound through the C–S moiety of the SCNMe

2

ligand.

The compounds 2, 4, and 5 were recrystallized from

CH

2

Cl

2

/n-hexane (1:10) and were isolated in 98%, 93%

and 92% yield, respectively.

Single crystals of 2, 4, and 5 suitable from X-ray

diﬀraction studies [6]were grown by slow n-hexane

diﬀusion into a dichloromethane solution at 4

°C.

OR-TEP plots of 2, 4, and 5 are shown in Figs. 2–4. In

Scheme 1.

Fig. 1. Variable-temperature1_{H (a) and}31_P{1_{H} NMR (b) spectra of the mixtures 2, 3, and 4 in CDCl}

3(x as the impurity). 578 K.-H. Yih et al. / Inorganic Chemistry Communications 6 (2003) 577–580

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complex 2, the SCNMe

2

ligand is r-bounding to Pd

atom through the carbon atom of the thiocarbonyl

group. The S–Pd bond distance of 3.033

A

A in 2 indicates

no bonding interaction between the sulfur atom and

palladium metal atom. Complex 4 is a dimer with each

SCNMe

2

unit bridging through carbon atom of

thio-carbonyl group to one metal center and sulfur atom to

the other metal. Within the SCNMe

2

ligands themselves,

the geometries are consistent with signiﬁcant partial

double bond character in the C–S and SC–N bonds.

Thus, the C–S bond distances (1.679(4)

A

A of 2, 1.731(4)

and 1.718(4)

A

A of 4, and 1.667(6)

A

A of 5) are comparable

to the C–S double bond in ethylenethiourea although

they are longer than those in free CS

2

(1.554

A

A). The

SC–N bond distances (1.320(4)

A

A of 2, 1.316(5) and

1.318(5)

A

A of 4, and 1.303(7)

A

A of 5) are typical for a

C–N bond having partial double bond character and are

certainly much shorter than the normal C–N (1.47

A

A)

single bond. The Me–N distances are normal for single

bonds and are signiﬁcantly longer than those of SC–N

bonds, which, as noted, have multiple bond character.

In complex 5, the Pd atom and its neighboring atoms,

P(1), P(2), S(1), and C(1) lie in a distorted squared plane.

The distortion is mainly due to the short bite of the C

@S

linkage [C–Pd–S, 44.54(16)°]. A least-squares plane cal

culation reveals that the planarity of the P(2)P(1)C(1)

S(1) core (largest deviation 0.031(1)

A

A). The C(1)–S(1)

bond distance of 1.667(6)

A

A is similar to the

corre-sponding carbon–sulfur bond distance observed in

g

2

_-CS

2

(sp

2

) transition-metal complexes [1.65(3)

A

A in

[ðPPh

3

Þ

2

Pdðg

2

-CS

2

Þ][7]

. The Pd–S(1) distance of

2.3243(5)

A

A is within the normal Pd–S length range

(2.23–2.32

A

A) [8]. Our interest in the M–CðSÞNMe

2

and

M–C(S)OPh moieties are due to their analogies with

metallocarboxylic acid esters (M–C(O)OR) and

metal-locarboxylic acids themselves. Metalmetal-locarboxylic acids

have been proposed to be the key intermediates in the

homogeneous catalysis of the water gas shift reaction

Fig. 2. An ORTEP drawing with 30% thermal ellipsoids and

atom-numbering scheme for the complex [PdðPPh3Þ2ðg1-SCNMe2ÞðClÞ], 2. Selected bond distances (AA) and angles (°) are as follows: Pd–P(1) 2.3531(9), Pd–P(2) 2.3401(9), Pd–Cl(1) 2.4067(9), Pd–C(1) 1.982(3), C(1)–S(1) 1.679(4), C(1)–N(1) 1.320(4), C(2)–N(1) 1.458(5), C(3)–N(1) 1.457(5); C(1)–Pd–Cl(1) 166.32(10), P(1)–Pd–P(2) 173.75(3), Cl(1)–Pd– P(1) 93.50(3), Cl(1)–Pd–P(2) 91.13(3), C(1)–Pd–P(1) 87.50(10), C(1)– Pd–P(2) 89.00(10), S(1)–C(1)–Pd 111.61(18), S(1)–C(1)–N(1) 124.7(3), N(1)–C(1)–Pd 123.6(3).

Fig. 3. An ORTEP drawing with 50% thermal ellipsoids and atom-numbering scheme for the complex ½PdðPPh3ÞCl2 ðl; g2 -SCNMe2Þ2, 4. Selected bond distances (AA) and angles (°) are as follows: Pd(1) Pd(2) 3.334(2), Pd(1)–P(1) 2.3046(10), Pd(2)–P(2) 2.3013(9), Pd(1)–Cl(1) 2.3721(10), Pd(2)–Cl(2) 2.3677(9), Pd(1)–C(1) 1.969(4), Pd(2)–C(4) 1.989(4), C(1)–S(1) 1.731(4), C(4)–S(2) 1.718(4); C(1)–Pd(1)–Cl(1) 178.55(11), C(4)–Pd(2)–Cl(2) 178.05(10), Cl(1)– Pd(1)–P(1) 87.26(3), Cl(2)–Pd(2)–P(2) 84.95(3), C(1)–Pd(1)–P(1) 93.41(11), C(4)–Pd(2)–P(2) 93.51(10), S(1)–C(1)–Pd(1) 116.93(19), S(2)–C(4)–Pd(2) 117.7(2).

Fig. 4. An ORTEP drawing with 30% thermal ellipsoids and atom-numbering scheme for the cationic complex½PdðPPh3Þ2ðg2-SCNMe2Þ ½PF6, 5. Selected bond distances (AA) and angles (°) are as follows: Pd– P(1) 2.3125(15), Pd–P(2) 2.3660(16), Pd–S(1) 2.3243(15), Pd–C(1) 2.003(6), C(1)–S(1) 1.667(6), C(1)–N(1) 1.303(7), C(2)–N(1) 1.468(7), C(3)–N(1) 1.466(7); C(1)–Pd–S(1) 44.54(16), P(1)–Pd–P(2) 103.66(5), S(1)–Pd–P(1) 151.36(6), S(1)–Pd–P(2) 104.92(5), C(1)–Pd–P(1) 106.82(16), C(1)–Pd–P(2) 149.15(16), S(1)–C(1)–Pd 78.0(2), S(1)–C(1)– N(1) 131.5(4), N(1)–C(1)–Pd 150.5(4), C(1)–S(1)–Pd 57.4(2). K.-H. Yih et al. / Inorganic Chemistry Communications 6 (2003) 577–580 579

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[9]. Reactions and diﬀerent bonding modes of 2 and

nucleophiles are currently under investigation.

Acknowledgements

We thank the National Science Council of Taiwan,

the Republic of China (NSC91-2113-214-002) for

sup-port.

References

[1](a) C.R. Green, R.J. Angelici, Inorg. Chem. 11 (1972) 2095; (b) R.J. Angelici, Acc. Chem. Res. 5 (1972) 335;

(c) A.W. Gal, H.P.M.M. Ambrosius, A.F.J.M. Van der Ploge, W.P. Bosman, J. Organomet. Chem. 149 (1978) 81;

(d) W.K. Dean, J.B. Wetherington, J.W. Moncrieﬀ, Inorg. Chem. 15 (1976) 1566;

(e) W.P. Bosman, A.W. Gal, Cryst. Struct. Commun. 4 (1975) 465; (f) L. Ricard, J. Estienne, R. Weiss, Inorg. Chem. 12 (1973) 2182; (g) G.L. Miessler, L.H. Pignolet, Inorg. Chem. 18 (1979) 210; (h) S.K. Porter, H. White, C.R. Green, R.J. Angelici, J. Clardy, J. Chem. Soc., Chem. Commun. (1973) 493;

(i) C. Mahe, H. Patin, A. Benoit, J. Le Marouille, J. Organomet. Chem. 216 (1981) C15;

(j) P.F. Gilletti, D.A. Femec, T.M. Brown, Inorg. Chem. 31 (1992) 4008;

(k) R.S. Herrick, S.J. Nieter-Burgmayer, J.L. Templeton, J. Am. Chem. Soc. 105 (1983) 2599;

(l) S.J. Nieter-Burgmayer, J.L. Templeton, Inorg. Chem. 24 (1985) 3939;

(m) D.C. Brower, T.L. Tonker, J.R. Morrow, D.S. Rivers, J.L. Templeton, Organometallics 5 (1986) 1094;

(n) E. Carmona, E. Gurierrez-Puebla, A. Monge, P.J. Perez, L.J. Sanchez, Inorg. Chem. 28 (1989) 2120;

(o) J.C. Jeﬀery, M.J. Went, J. Chem. Soc. Dalton Trans. (1990) 567; (p) S. Anderson, D.J. Cook, A.F. Hill, Organometallics 20 (2001) 2468;

(q) W.K. Dean, J. Organomet. Chem. 190 (1980) 353;

(r) D.H.M.W. Thewissen, J.G. Noltes, Inorg. Chim. Acta. 59 (1982) 181;

(s) J.A.E. Gibson, M. Cowie, Organometallics 3 (1984) 722; (t) X.L. Fan, R. Cao, M.C. Hong, W.P. Su, D.F. Sun, J. Chem. Soc. Dalton Trans (2001) 2961.

[2](a) K.H. Yih, Y.C. Lin, M.C. Cheng, Y. Wang, Organometallics 13 (1994) 1561;

(b) K.H. Yih, Y.C. Lin, G.H. Lee, Y. Wang, J. Chem. Soc., Chem. Commun. (1995) 223;

(c) K.H. Yih, G.H. Lee, Y. Wang, Inorg. Chem. 39 (2000) 2445; (d) K.H. Yih, G.H. Lee, Y. Wang, Inorg. Chem. Commun. 6 (2003) 213.

[3]Spectroscopy for 2:31_{P {}1_{H} NMR: d 16.6 (br, PPh}

3).1H NMR: d

2.34, 2.64 (s, 6H, NCH3), 7.31–8.05 (m, 30H, Ph).13C{1H} NMR: d

41.5 (s, NCH3), 128.4–135.8 (m, C of Ph), 223.5 (s, CS). Anal.

Calcd. for C39H36ClNP2SPd: C, 62.08; H, 4.81; N, 1.86%. Found:

C, 62.10; H, 4.81; N, 1.84. Spectroscopy for 3:31_P{1_{H} NMR: d} 23.1, 35.1 (d,2_J P–P¼ 40:7).1H NMR: d 2.39, 3.58 (s, 6H, NCH3), 7.31–8.05 (m, 30H, Ph).13_C{1_{H} NMR: d 46.1, 53.4 (s, NCH} 3), 128.4–135.8 (m, C of Ph). Spectroscopy for 4:31_P{1_{H} NMR: d} 19.8 (s, PPh3).1H NMR: d 2.51, 3.44 (s, 6H, NCH3), 7.28–8.05 (m, 15H, Ph).13_C{1_{H} NMR: d 39.9, 49.1 (s, NCH} 3), 128.4–135.8 (m,

C of Ph), 234.4 (s, CS). Anal. Calcd. for C42H42Cl2N2P2S2Pd2: C,

51.23; H, 4.30; N, 2.85%. Found: C, 51.28; H, 4.21; N, 2.80. [4](a) G. Yoshida, H. Kurosawa, R. Okawara, J. Organomet. Chem.

113 (1976) 85;

(b) J.F. Ma, Y. Kojima, Y. Yamamoto, J. Organomet. Chem. 616 (2000) 149. [5]Spectroscopy for 5: IR (KBr, tPF6=cm1): 839 (vs).31P{1H} NMR: d23.2, 34.8 (d,2_J P–P¼ 40:7, PPh3),)144.0 (sep, JP–F¼ 708:6, PF6). 1_{H NMR: d 2.45, 3.61 (s, 6H, NCH} 3), 7.24–7.73 (m, 30H, Ph).13C {1_{H} NMR: d 45.9, 53.9 (s, NCH} 3), 128.8–134.0 (m, C of Ph), 212.1 (d, CS,2_J

P–C¼ 6:7). Anal. Calcd. for C39H36F6NP3SPd: C, 54.21;

H, 4.20; N, 1.62 %. Found: C, 54.25; H, 4.18; N, 1.70.

[6]Crystal data for 2: C39H36ClN2P2PdS, space group P21=n,

a¼ 12:8248ð1Þ AA, b¼ 18:6358ð1Þ AA, c¼ 14:9692ð1Þ AA, b¼ 105:1513ð4Þ°, V ¼ 3453:28ð5Þ AA3, Z¼ 4, Dcalcd¼ 1:451 gcm3,

l¼0:797 mm1_{, independent reﬂections 24,507, h}

range¼ 1:78–

27:50°. Total number of parameters: 407. R ¼ 0:043, Rw¼ 0:090;

GOF¼ 1.049, Mo-Ka radiation; k ¼ 0:71073 AA; T¼ 150ð1Þ K; DF¼ 0:843, )0.893e AA3. Crystal data for 4 CH2Cl2: C43H44

Cl4N2P2Pd2S2, space group P1, a¼ 9:8782ð1Þ AA, b¼ 11:4238ð1Þ AA,

c¼ 20:7353ð2Þ AA, a¼ 103:9126ð5Þ°, b¼ 97:8453ð3Þ° c¼ 104:9669ð5Þ°, V ¼ 2166:76ð4Þ AA3, Z¼ 2, Dcalcd¼ 1:639 gcm3,

l¼ 1:281 mm1_{, independent reﬂections 39,233, h}

range¼ 1:02–

27:50°. Total number of parameters: 497. R ¼ 0:0409, Rw¼

0:0969; GOF¼ 1.103, Mo-Ka radiation; k ¼ 0:71073 AA; T¼ 150ð1Þ K; DF ¼ 1:730, )1.261e AA3. Crystal data for 5: C39H36F6NP3PdS CH2Cl2, space group P21=c, a¼ 9:8101ð1Þ AA,

b¼ 23:5315ð3Þ AA, c¼ 18:2112ð2Þ AA, b¼ 103:2337ð5Þ°, V ¼ 4092:35ð4Þ AA3, Z¼ 4, Dcalcd¼ 1:540 gcm3;l¼ 0:810 mm1,

inde-pendent reﬂections 27,983, hrange¼ 1:44–27:50°. Total number of

parameters: 498. R¼ 0:064, Rw¼ 0:148; GOF ¼ 1.038, Mo-Ka

radiation; k¼ 0:71073 AA ; T¼ 150ð1Þ K; DF ¼ 1:543,)1.136e AA3. Absorption corrections of 2, 4, and 5 have been carried out. These structures were solved by Patterson synthesis and then refined via standard least-squares and difference Fourier tech-niques. Non-hydrogen atoms were refined by using anisotropic thermal parameters.

[7]T. Kashiwagi, N. Yasuoka, T. Ueki, N. Kasai, M. Kakudo, S. Takahashi, N. Hagihara, Bull. Chem. Soc. (1968) 296.

[8]H.L. Bozec, P.H. Dixneuf, A.J. Carty, N.J. Taylor, Inorg. Chem. 17 (1978) 2568.

[9]T. Yoshida, Y. Ueda, S. Otsuka, J. Am. Chem. Soc. 100 (1978) 3941.