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Polyhedron 25 (2006) 1449–1456

Synthesis and crystal structure analysis offerrocenylthiosemicarbazone complexes of palladium(II):

Unusual rPd–C bond cleavage

Marta Marino a, Eduardo Gayoso a, Jose M. Antelo a, Luis A. Adrio a,Jesus J. Fernandez b, Jose M. Vila a,*

a Departamento de Quımica Inorganica, Universidad de Santiago de Compostela, Avenida de las Ciencias s/n, E-15782 Santiago de Compostela, Spainb Departamento de Quımica Fundamental, Universidad de La Coruna, E-15071 La Coruna, Spain

Received 16 September 2005; accepted 11 October 2005Available online 22 November 2005

Abstract

The reaction of the thiosemicarbazones (g5-C5H5)Fe(g5-C5H4)C(H)@NN(H)C(@S)NHR (R = H, a; R = Me, b) with K2PdCl4 affor-ded octanuclear cyclometallated complexes [Pd{(g5-C5H5)Fe(g5-C5H3)C(H)@NN@C(S)NHR}]4 (R = H, 1a; R = Me, 1b). Reaction ofcomplexes 1a and 1b with tertiary diphosphines in 1:2 molar ratio and subsequent recrystallization from CH2Cl2/n-C6H14 gave rise totetranuclear complexes [{Pd[(g5-C5H5)Fe(g5-C5H4)C(H)@NN@C(S)NHR](Cl)}2(l-Ph2P(CH2)nPPh2)] (R = H, n = 4, 2a; R = Me,n = 1, 2b; n = 4, 3b). Treatment of complexes 1a and 1b with tertiary monophosphines in 1:4 molar ratio and subsequent recrystallizationfrom CH2Cl2/n-C6H14 gave rise to dinuclear complexes [Pd{(g5-C5H5)Fe(g5-C5H4)C(H)@NN@C(S)–NHR}(Cl)(P)] (R = H: P = PPh3,3a; P = PPh2Et, 4a; P = P(C6D5)3, 5a; R = Me: P = PPh3, 4b; P = PPh2Et, 5b; P = P(C6D5)3, 6b). The crystal structures of 2a and 2b

have been determined by X-ray crystallography.� 2005 Elsevier Ltd. All rights reserved.

Keywords: Palladium; Cyclometallation; Phosphines; Thiosemicarbazones; Crystal structure

1. Introduction

Cyclometallated complexes [1] have generated a greatinterest in the past mainly due to their applications as pre-cursors of new organometallic and organic compounds [2],their use in homogeneous catalysis [3] as chiral recognitionagents [4], or their promising photochemical [5] and lumi-nescent properties [6].

The synthesis, isolation and characterization of ferro-cene marked an imported point in the evolution of modernorganometallic chemistry [7] and a half century later,research into ferrocene-containing compounds, and of agreat deal of analogous sandwiched compounds with tran-sition metals other than iron, is quickly growing [8], owingto the role the ferrocene moiety plays, itself being the back-

0277-5387/$ - see front matter � 2005 Elsevier Ltd. All rights reserved.

doi:10.1016/j.poly.2005.10.003

* Corresponding author. Tel.: +34 981 52800; fax: +34 981 595012.E-mail address: qideport@usc.es (J.M. Vila).

bone of the molecule, or a substituent in ancillary ligands,and also due to the unique geometries and electronic prop-erties that ferrocene provides [9]. One of the developmentsin this area over the past two decades is the cyclometalla-tion of ferrocene derivatives, which usually results in theformation of planar chiral cyclometallated metallocenes;the resulting products distinguish the reaction from thecyclometallation of other ligands, and they exhibit greatpotential use in asymmetric synthesis. The most commonligands are by far [C,N] bidentate ligands [10], and theirapplication as highly active catalysts for the Heck reaction[11] and for asymmetric intramolecular aminopalladation[12] has been established, as well as being auxiliary reagentsfor chiral recognition or discrimination [13].

More recently a great effort has been made in order toextend the work in this area to the isolation andcharacterization of similar complexes derived from terden-tate [C,N, X] ligands. Thus, palladacycles derived from

N

Pd

S

NNHR

41a, 1b

CpFeCpFe

N

HN NHR

S

a: R = Hb: R = Me

i

2

3 4

5

N N

CpFePd S

NHR

Cl

PPh2

NN

FeCpPdS

RHN

Cl

Ph2P

2a2b, 3b

N N

CpFePd S

NHR

Cl

P

3a-5a4b-6b

iiiii

Scheme 1. (i) K2PdCl4, ethanol/water; (ii) Ph2P(CH2)nPPh2 (n = 1, 2b;n = 4, 2a, 3b) 1:2 molar ratio, acetone, CH2Cl2/hexane; (iii) P(PPh3, 3a, 4b;PPh2Et, 4a, 5b; P(C6D5)3, 5a, 6b) 1:4 molar ratio, acetone, CH2Cl2/hexane.

1450 M. Marino et al. / Polyhedron 25 (2006) 1449–1456

[C(sp2/aryl or sp3),N, X] terdentate ligands are well knownand many examples have been reported with X = N [14], S[15], O [16], mainly due to the potential hemilability of thePd–X bond in these systems, which plays an importantrole in homogeneous catalysis. Nevertheless all the exam-ples reported for those complexes containing terdentate[C(sp2/ferrocene),N, X] ligands are scarce, and to the bestof our knowledge only compounds with X = N [17] and S[17b,17d,18] have been described, and recently ferrocene-based pincer complexes of palladium have been reported,bearing a terdentate [P,C,P] ligand [19]. Ferrocene-basedcyclometallated complexes with [C,N, S] ligands are mainlywith thioethers, and the unique examples derived from thi-osemicarbazones have been recently reported by us [20]. Asa continuation of our studies related to ferrocenylthiosemic-arbazone ligands, herein we report the synthesis and charac-terization of new polynuclear organometallic andcoordination compounds, the latter being generated afterunusual rPd–C bond cleavage in the starting material.

2. Results and discussion

2.1. Synthesis and characterization

The thiosemicarbazones (g5-C5H5)Fe(g5-C5H4)C(H)@NN(H)C(@S)NHR (R = H, a; R = Me, b) were obtainedby reaction of ferrocenecarboxaldehyde with thiosemicar-bazide or with 4-methylthiosemicarbazide, respectively, inH2O in the presence of HCl at room temperature. TheNH2 protons gave rise to two characteristic resonances at6.33 and 7.10 ppm in the 1H NMR spectrum of ligand a

which were attributed to the restricted rotation of the NH2

group about the C(@S)NH2 axis. The NH protons showedresonances at 9.79 (a), 7.34 (NHMe, b) and 9.41 ppm(NH, b). A singlet ca. 7.80 ppm was assigned to the HC@Nproton, and two apparent triplets ca. 4.50 ppm wereascribed to the H2/H5 and H3/H4 protons of the substi-tuted ferrocenyl ring, as a simplification of the expected 20lines of the theoretical spectrum for an AA 0XX 0 spin system.The C5H5 resonance appeared as a singlet at 4.20 ppm. Theresulting new complexes derived from a and b are shown inScheme 1. Preparative details, characterising microanalyti-cal, IR, 1H and 31P–{1H} NMR data are in Section 4.

Thus, treatment of a suspension of K2PdCl4 in EtOH/H2O with the corresponding thiosemicarbazone affordedthe cyclometallated complexes [Pd{(g5-C5H5)Fe(g5-C5H3)C(H)@NN@C(S)NHR}]4 (R = H, 1a; R = Me, 1b),with the ligand in the E/Z configuration for which an octa-nuclear structure is proposed following the trend for theseand other related compounds of tridentate [C,N, S] ligands[21]; the FAB mass spectra of 1a and 1b showed clusters ofpeaks, centred at 1566 and 1622 amu, which correspond to[M]+, supporting the proposed formulation. The sulfuratom of each cyclometallated moiety displaying twodifferent coordination modes: chelating, as part of thePdNNC(NHR)S coordination ring, and bridging, linkingtwo cyclometallated moieties through the metal atoms.

The absence of the signal for the NH group in the 1HNMR spectra was in agreement with deprotonation [22].The NH2 (1a) and NHMe (1b) resonances appeared as asinglet (5.34 ppm) and a broad signal (5.37 ppm), respec-tively, shifted to lower frequency with respect to the spectraof the free ligands. Metallation of the ligand was clear fromthe absence of the AA 0XX 0system of the C5H4 ring; threeproton resonances were assigned to the new C5H3 ring(see Section 4). In the IR spectra, the presence of them(N–H) band ca. 3420 cm�1 indicated the NHR groupwas not coordinated, and absence of the m(N–H) bandfor the NNH group confirmed deprotonation of the latter[23]. The m(C@N) band was shifted to lower wavenumbersupon complex formation [24] in an opposite trend to thatobserved in other thiosemicarbazones complexes [23],which can be attributed to the C,N moiety being part ofthe five-membered metallacycle [25]. The band assignedto the m(C@S) stretching vibration ca. 870 cm�1 in the freeligands disappeared in the spectra of the complexes, inaccordance with loss of the C@S double bond characterupon deprotonation of the NH group.

Treatment of complexes 1a and 1b with tertiarydiphosphines (1:2 molar ratio) or monophosphines (1:4molar ratio) in acetone at room temperature and ulteriorrecrystallization from CH2Cl2/n-C6H14 gave rise to tetra-nuclear or dinuclear complexes, respectively, with loss ofthe metallated ring upon cleavage of the rPd–C bond,as opposed to the case of similar complexes with ferroce-nylthiosemicarbazones obtained by us earlier [21b], where

Fig. 1. Molecular structure of [{Pd[(g5-C5H5)Fe(g5-C5H4)C(H)@NN@C(S)NH2](Cl)}2{l-Ph2P(CH2)4PPh2}] (2a), with labelling scheme. Hydrogenatoms have been omitted for clarity.

M. Marino et al. / Polyhedron 25 (2006) 1449–1456 1451

the metal–carbon bond was retained. These results,together with our most recent findings1, allow us to antic-ipate possible reasons for the behaviour of these com-plexes: (a) the absence of the MeC@N methyl group inthe present complexes seems to favour demetallation ofthe cyclopentadienyl ring; (b) under the reaction condi-tions employed the source of chlorine should be eitherdichloromethane, which would put forward the non-spec-tator character of this solvent, or possibly traces of acid inthe solvent; (c) it is also noteworthy to point out that thelatter could account for the proton source and act ascatalyst in the process [26]. Thus, reaction of 1a and 1b

with tertiary diphosphines (Ph2PCH2PPh2, Ph2P(CH2)4-PPh2, 1:2 molar ratio) or with tertiary monophosphines(PPh3, PPh2Et, P(C6D5)3, 1:4 molar ratio) gave the tetra-nuclear complexes [{Pd[(g5-C5H5)Fe(g5-C5H4)C(H)@NN@C(S)NHR]-(Cl)}2(l-PP)] (2a, 3b: PP = Ph2P(CH2)4PPh2;2b, PP = Ph2PCH2PPh2; see Scheme 1) and the dinuclearcomplexes [Pd{(g5-C5H5)Fe(g5-C5H4)C(H)@NN@C(S)-NHR}(Cl)(P)] (3a, 4b: P = PPh3; 4a, 5b: P = PPh2Et; 5a,6b, P = P(C6D5)3; see Scheme 1), respectively; with thediphosphine acting as a bridging ligand between the twopalladium atoms in the former case. In the IR spectra,the absence of the m(C@S) stretching vibration and ofthe m(N–H) band for the NNH group, as well as the shiftto lower wavenumbers of the m(C@N) band was in accor-dance with [N, S] coordination of the deprotonated ferr-ocenylthiosemicarbazone ligands to the palladium atom.A band ca. 310 cm�1 was assigned to the m(Pd–Cl) vibra-tion, in accordance with the now present terminal Pd–Cl

1 Recently, we have found that related ligands with five-membered rings,such as pyrrol, furane and thiophene thiosemicarbazones, are difficult tometallate or they do not undergo cyclometallation at all when the iminecarbon, C@N, is bonded to hydrogen (for pyrrol derivatives see J.M. Vilaet al., Z. Anorg. Allg. Chem., 635 (2005) 2197); however, ligands withalkyl substituted C@N groups readily undergo cyclometallation (A.Amoedo, Ph.D. Dissertation, Universidad de Santiago de Compostela,Santiago).

bonding. In the 1H NMR spectra, two apparent tripletsassigned to the H2/H5 and H3/H4 protons (AA 0XX 0 sys-tem) confirmed the regeneration of the substituted ferro-cene ring, whilst absence of the –NH resonancesuggested the hydrazynic nitrogen atom remained depro-tonated. The HC@N resonance ca. d 8.30 ppm appearedas a doublet due to coupling with the 31P nucleus[4J(PHi) ca. 4.0 Hz], thereby indicating a phosphorustrans to nitrogen geometry, within the terms of the ‘‘trans-phobic effect’’ [27]; in the case of complexes 2a, 2b, 3b, the1H NMR spectra showed only one set of signals puttingforward the symmetric nature of these complexes. The31P–{1H} NMR spectra showed a singlet, shifted tohigher frequency from the spectrum of the free phosphine,in agreement with phosphorus coordination to metal cen-ter; for complexes 2a, 2b, 3b, this showed that the twophosphorus nuclei were equivalent [28] as might beexpected from the 1H NMR data (vide supra).

2.2. Molecular structures of compounds 2a and 2b

Suitable crystals of 2a and 2b were grown by slowlyevaporating CH2Cl2/n-C6H14 solutions. The molecularstructure of each neutral compound with the numberingscheme is illustrated in Figs. 1 and 2, respectively. Selectedbond lengths and angles are listed in Table 1. The struc-tures consist in discrete molecules separated by van derWaals distances (Table 2).

The crystal structures comprise a half molecule perasymmetric unit, and exhibit C2 symmetry about thePCH2CH2–CH2CH2P bond (2a) or the central PCH2Pgroup (2b). The four-coordinated palladium(II) atoms arebonded to an iminic nitrogen atom and a thioamide sul-phur atom of the deprotonated thiosemicarbazone ligand,and to a chlorine atom (trans to S). A phosphorus atomfrom the diphosphine ligand, which bridges the two palla-dium atoms, completes the metal coordination sphere. Thesum of angles about palladium are 360.28� (2a) and 360.05�

1452 M. Marino et al. / Polyhedron 25 (2006) 1449–1456

(2b), with the distortion most noticeable in the somewhatreduced ‘‘bite’’ angle of the thiosemicarbazone moiety con-sequent upon chelation (83.37(15)� for 2a, 83.1(3)� for 2b).The geometry around the palladium atom is slightly dis-torted square-planar, the mean deviation from the leastsquares plane (plane 1: Pd(1), N(1), S(1), P(1), Cl(1) are0.0783 (2a) and 0.0731 (2b)). The metallated rings (plane2: Pd(1), S(1), C(12), N(1), N(2), r.m.s. 0.0261 (2a),

Fig. 2. Molecular structure of [{Pd[(g5-C5H5)Fe(g5-C5H4)C(H)@NN@C(S)NHhave been omitted for clarity.

Table 1Crystal and structure refinement data

2a

Formula C52H52

Formula weight 1282.46Temperature (K) 293(2)Wavelength (A) 0.71073Crystal system monoclSpace group P2(1)/ca (A) 10.339(b (A) 17.785(c (A) 13.894(a (�) 90b (�) 93.389(c (�) 90V ( A3) 2550.4(Z 2Dcalc (Mg/m3) 1.670Absorption coefficient (mm�1) 1.544F(000) 1292Crystal size (mm3) 0.34 · 0h Range for data collection (�) 1.86–26Index ranges �5/2, �Reflections collected 13790Independent reflections [Rint] 5209 [0Completeness to h = 26.43� 99.3%Absorption correction SADABS

Refinement method full-maData/restraints/parameters 5209/0/Goodness-of-fit on F2 0.955Transmissions 0.870, 0Final R indices [I > 2r(I)] R1 = 0.R indices (all data) R1 = 0.Largest difference in peak and hole (e A�3) 0.748 a

0.0433 (2b)) are also planar and coplanar with the palla-dium coordination plane (angles between planes: 1/23.83(0.12)� (2a), 4.56(0.10)� (2b)).

The palladium–nitrogen bond lengths (2.107(5) A, 2a;2.079(9) A, 2b) are longer than the predicted single bondvalue of 2.011 A, based on the sum of covalent radii fornitrogen(sp2) and palladium, 0.701 and 1.31 A, respectively[29] and reflects the trans influence of the phosphorus atom

Me](Cl)}2(l-Ph2PCH2PPh2)] (2b), with labelling scheme. Hydrogen atoms

2b

Cl2Fe2N6P2Pd2S2 C53H52Cl8Fe2N6P2Pd2S2

1507.17293(2)0.71073

inic monoclinicP2/c

3) 15.408(4)5) 8.750(2)4) 22.489(5)

905) 94.400(5)

9012) 3023.0(12)

21.6561.5721508

.29 · 0.09 0.36 · 0.33 · 0.31

.43 1.33–26.4412/22, �17/16 �14/19, �10/10, �28/28

16756.0621] 6147 [0.1091]

98.9%SADABS

trix least-squares on F2

307 6147/0/3390.881

.600 0.6414, 0.60140457, wR2 = 0.0762 R1 = 0.0550, wR2 = 0.11961219, wR2 = 0.0883 R1 = 0.2005, wR2 = 0.1851nd �0.502 0.635 and �0.686

Table 2Selected bond distances (A) and angles (�) for 2a and 2b

2a

Pd(1)–N(1) 2.107(5) Pd(1)–S(1) 2.2436(17)Pd(1)–P(1) 2.2543(16) Pd(1)–Cl(1) 2.3397(16)S(1)–C(12) 1.776(6) N(1)–N(2) 1.390(6)N(2)–C(12) 1.280(7) N(3)–C(12) 1.344(7)N(1)–C(11) 1.281(6) C(1)–C(11) 1.436(7)P(1)–C(13) 1.825(6) C(14)–C(13) 1.518(7)

N(1)–Pd(1)–S(1) 83.37(15) N(1)–Pd(1)–P(1) 175.04(14)S(1)–Pd(1)–P(1) 92.54(6) N(1)–Pd(1)–Cl(1) 94.47(15)S(1)–Pd(1)–Cl(1) 173.41(6) P(1)–Pd(1)–Cl(1) 89.90(6)C(11)–N(1)–N(2) 115.9(5) C(11)–N(1)–Pd(1) 124.2(4)N(2)–N(1)–Pd(1) 119.9(4) C(12)–N(2)–N(1) 113.3(5)C(12)–S(1)–Pd(1) 96.6(2) N(2)–C(12)–S(1) 126.6(5)

2b

Pd(1)–N(1) 2.079(9) Pd(1)–S(1) 2.242(3)Pd(1)–P(1) 2.257(3) Pd(1)–Cl(1) 2.350(3)S(1)–C(12) 1.773(11) N(1)–C(11) 1.285(12)N(1)–N(2) 1.401(10) N(2)–C(12) 1.296(13)N(3)–C(12) 1.313(12) N(3)–C(13) 1.485(13)C(1)–C(11) 1.425(13) P(1)–C(26) 1.815(7)

N(1)–Pd(1)–S(1) 83.1(3) N(1)–Pd(1)–P(1) 178.0(3)S(1)–Pd(1)–P(1) 94.89(11) N(1)–Pd(1)–Cl(1) 94.2(3)S(1)–Pd(1)–Cl(1) 171.99(11) P(1)–Pd(1)–Cl(1) 87.86(10)C(12)–S(1)–Pd(1) 97.3(4) C(11)–N(1)–N(2) 114.5(9)C(11)–N(1)–Pd(1) 124.1(7) N(2)–N(1)–Pd(1) 121.0(6)C(12)–N(2)–N(1) 112.5(9) N(2)–C(12)–S(1) 125.6(8)

M. Marino et al. / Polyhedron 25 (2006) 1449–1456 1453

[30,31]. The palladium–sulfur bond lengths, (2.2436(17) A,2a; 2.242(3) A, 2b) are shorter than the expected value of2.33 A (based on the sum of the covalent radii for sulfurand palladium, 1.02 and 1.31 A, respectively). The Pd–Pbond distances, 2.2543(16) (2a) and 2.257(3) (2b) areshorter than the sum of the single bond radii for palladiumand phosphorus (2.41 A), whilst the Pd–Cl bond lengths,2.3397(16) (2a) and 2.350(3) A (2b), are slightly longer thanthe sum of the covalent radii (2.30 A). The S–C and C–Nbond lengths in the chelate ring [S(1)–C(12), 1.776(6),N(2)–C(12), 1.280(7) A, 2a; S(2)–C(39), 1.773(11), N(5)–C(39), 1.296(13) A, 2b] are consistent with increased singleand double bond character, respectively.

3. Conclusions

The results reported in the present paper show that ferr-ocenyl thiosemicarbazones are readily metallated to givethe corresponding cyclopalladated octanuclear complexes.However, reaction of the latter with tertiary mono- anddiphosphines yields products with cleavage of the Pd–Cbond, protonation of the cyclopentadienyl ring, andPd–Cl bond formation. These results, together with veryrecent findings from our laboratory, allow us to point outseveral factors responsible for this behaviour such as arethe absence of an alkyl group on the imine carbon atom,the presence of traces of acid in CH2Cl2, and the not sonegligible reactivity of this solvent. We are currently under-taking the research of related chemistry aimed at providing

further proof for our proposal, which shall be communi-cated in the near future.

4. Experimental

Solvents were purified by standard methods [32], chem-icals were reagent grade. Microanalyses were carried out atthe Servicio de Analisis Elemental at the University of San-tiago using a Carlo Erba Elemental Analyzer, Model 1108.IR spectra were recorded on a Perkin–Elmer 1330 and on aMattson spectrophotometer. NMR spectra were obtainedas CDCl3 solutions and referenced to SiMe4 (1H) or 85%H3PO4 (31P–{1H}) and were recorded on Bruker WM250and AMX-300 spectrometers (only selected data is pre-sented for compounds containing phosphine). All chemicalshifts are reported downfield from standards. The FABmass spectra were recorded with a Fisons Quatro massspectrometer with a Cs ion gun; 3-nitrobenzyl alcoholwas used as the matrix.

4.1. (g5-C5H5)Fe(g5-C5H4)C(H)@NN(H)C(@S)NH2 (a)

To a stirred suspension of thiosemicarbazide (0.213 g,2.336 mmol) in water (40 cm3) a few drops of HCl 36%and ferrocenecarboxaldehyde (0.5 g, 2.336 mmol) wereadded. The resulting mixture was stirred for 4 h at r.t., fil-tered off, washed with water and dried in vacuo to yield anorange solid.

Yield: 91.4%. Anal. Calc. for C12H13N3FeS: C, 50.2; H,4.6; N, 14.7; S, 11.2. Found: C, 49.7; H, 4.4; N, 14.2; S,11.1%. IR: m(N–H) 3431m, 3151w, m(C@N) 1592m,m(C@S) 876 cm�1. 1H NMR (d ppm, J Hz): 4.20 (s, 5H,C5H5), 4.32 (t, 2H, H3/H4, N = 3.4), 4.58 (t, 2H, H2/H5,N = 3.4), 6.33, 7.10 (s, 2H, NH2), 7.80 (s, 1H, HC@N),9.79 (s, 1H, NH).

Ligand b was prepared as an orange air-stable solidfollowing a similar procedure.

4.2. (g5-C5H5)Fe(g5-C5H4)C(H)@NN(H)C(@S)NHMe (b)

Yield: 93.5%. Anal. Calc. for C13H15N3FeS: C, 51.8; H,5.0; N, 14.0; S, 10.6. Found: C, 51.5; H, 5.0; N, 13.5; S,10.1%. IR: m(N–H) 3430m, 3143w, m(C@N) 1609m,m(C@S) 873 cm�1. 1H NMR (d ppm, J Hz): 3.24 (d, 3H,NHMe, 3J(HMe) = 4.8 Hz), 4.20 (s, 5H, C5H5), 4.40 (at,2H, H3/H4, N = 3.8), 4.57 (at, 2H, H2/H5, N = 3.8), 7.34(b, 1H, NHMe), 7.69 (s, 1H, HC@N), 9.41 (s, 1H, NH).

4.3. [Pd{(g5-C5H5)Fe(g5-C5H3)C(H)@NN@C(S)-

NH2}]4 (1a)

To a stirred solution of K2PdCl4 (200 mg, 0.613 mmol)in EtOH (40 cm3) and H2O (6 cm3), (g5-C5H5)Fe(g5-C5H4)C(H)@NN(H)C(@S)NH2 (a) (193 mg, 0.674 mmol)were added. The mixture was stirred for 24 h at r.t. andthe resulting precipitate filtered off, washed with cold etha-nol and dried in vacuo.

1454 M. Marino et al. / Polyhedron 25 (2006) 1449–1456

Yield: 53.3%. Anal. Calc. for C48H44Fe4N12Pd4S4: C,36.8; H, 2.8; N, 10.7; S, 8.2. Found: C, 36.3; H, 2.8; N,10.3; S, 8.3%. IR: m(N–H) 3428m, m(C@N) 1525w. 1HNMR (d ppm, J Hz): 3.88 (b, 1H, H4), 4.06 (s, 5H,C5H5), 4.23 (b, 1H, H3), 4.35 (b, 1H, H2), 5.34 (s, 2H,NH2), 7.59 (s, 1H, HC@N).

Compound 1b was prepared as a red air-stable solidfollowing a similar procedure.

4.4. [Pd{(g5-C5H5)Fe(g5-C5H3)C(H)@NN@C(S)-

NHMe}]4 (1b)

Yield: 56.5%. Anal. Calc. for C52H52Fe4N12Pd4S4: C,38.5; H, 3.2; N, 10.4; S, 7.9. Found: C, 38.1; H, 3.1; N,10.5; S, 7.5%. IR: m(N–H) 3417m, m(C@N) 1601m. 1HNMR (d ppm, J Hz): 2.95 (d, 3H, NHMe,3J(HMe) = 4.8), 3.90 (d, 1H, H4, 3J(H3H4) = 1.2), 4.08(s, 5H, C5H5), 4.33 (b, 1H, H3), 4.40 (b, 1H, H2), 5.37(b, 1H, NHMe), 7.63 (s, 1H, HC@N).

4.5. [{Pd[(g5-C5H5)Fe(g5-C5H4)C(H)@NN@C(S)NH2]-

(Cl)}2{l-Ph2P(CH2)4PPh2}] (2a)

To a stirred solution of compound 1a (30 mg,0.018 mmol) in acetone (15 cm3) 1,4-bis(diphenylphosph-ino)butane (dppb) (16 mg, 0.038 mmol) was added. Themixture was stirred for 24 h at r.t., filtered off and the sol-vent removed under reduced pressure. The red residue wasrecrystallized from CH2Cl2/n-C6H14.

Yield: 66.9%. Anal. Calc. for C52H52Cl2Fe2N6P2Pd2S2:C, 48.7; H, 4.1; N, 6.6; S, 5.0. Found: C, 48.5; H, 4.0; N,6.2; S, 4.9%. IR: m(N–H) 3457m, m(C@N) 1533m, m(Pd–Cl) 305m cm�1. 1H NMR (d ppm, J Hz): 4.22 (s, 5H,C5H5), 4.45 (t, 2H, H3/H4, N = 3.4), 4.93 (t, 2H, H2/H5,N = 3.4), 4.68 (s, 2H, NH2), 8.31 (d, 1H, HC@N,4J(PH) = 4.2). 31P–{1H} NMR (d ppm) 19.1s.

Compounds 2b and 3b were prepared as red air-stablesolids following a similar procedure.

4.6. [{Pd[(g5-C5H5)Fe(g5-C5H4)C(H)@NN@C(S)-

NHMe](Cl)}2(l-Ph2PCH2PPh2)] (2b)

Yield: 61.7%. Anal. Calc. for C51H50Cl2Fe2N6P2Pd2S2:C, 48.3; H, 4.0; N, 6.6; S, 5.1. Found: C, 48.0 H, 4.2; N,6.8; S 4.9%. IR: m(N–H) 3440m, m(C@N) 1596m, m(Pd–Cl) 302m cm�1. 1H NMR (d ppm, J Hz): 2.94 (d, 3H,NHMe, 3J(HMe) = 4.9), 4.14 (s, 5H, C5H5), 4.19 (t, 2H,H3/H4, N = 3.8), 4.40 (t, 2H, H2/H5, N = 3.8), 5.39 (b,1H, NHMe), 8.21 (d, 1H, HC@N, 4J(PH) = 4.5). 31P–{1H} NMR (d ppm) 23.5s.

4.7. [{Pd[(g5-C5H5)Fe(g5-C5H4)C(H)@NN@C(S)NHMe](Cl)}2{l-Ph2P(CH2)4PPh2}] (3b)

Yield: 56.5%. Anal. Calc. for C56H54Cl2Fe2N6P2Pd2S2:C, 49.5; H, 4.3; N, 6.4; S, 4.9. Found: C, 49.1; H, 4.0; N,6.4; S, 4.4%. IR: m(N–H) 3417m, m(C@N) 1596m, m(Pd–

Cl) 323m cm�1. 1H NMR (d ppm, J Hz): 2.97 (b, 3H,NHMe), 4.23 (s, 5H, C5H5), 4.87 (t, 2H, H3/H4,N = 3.8), 5.04 (t, 2H, H2/H5, N = 3.8), 5.48 (b, 1H,NHMe), 8.33 (d, 1H, HC@N, 4J(PH) = 4.1). 31P–{1H}NMR (d ppm) 23.7s.

4.8. [Pd{(g5-C5H5)Fe(g5-C5H3)C(H)@NN@C(S)NH2}-

(Cl)(PPh3)] (3a)

To a stirred solution of compound 1a (30 mg,0.019 mmol) in acetone (15 cm3) triphenylphosphine(20 mg, 0.077 mmol) was added. The mixture was stirredfor 24 h at r.t., filtered off, dried in vacuo and the orangeresidue recrystallized from CH2Cl2/n-C6H14. Yield:52.1%. Anal. Calc. for C30H27ClFeN3PPdS: C, 52.2; H,3.9; N, 6.1; S, 4.6. Found: C, 52.0; H, 3.8; N, 6.4; S,4.7%. IR: m(N–H) 3449m, m(C@N) 1533m, m(Pd–Cl)304m cm�1. 1H NMR (d ppm, J Hz): 4.24 (s, 5H,C5H5), 4.46 (t, 2H, H3/H4, N = 3.4), 4.96 (t, 2H, H2/H5,N = 3.4), 4.63 (s, 2H, NH2), 8.41 (d, 1H, HC@N,4J(PH) = 4.0). 31P–{1H} NMR (d ppm) 26.2s.

Compounds 4a, 5a and 4b–6b were prepared as air-stable solids following a similar procedure.

4.9. [Pd{(g5-C5H5)Fe(g5-C5H3)C(H)@NN@C(S)NH2}-

(Cl)(PPh2Et)] (4a)

Yield: 56.9%. Anal. Calc. for C26H27ClFeN3PPdS: C,48.6; H, 4.2; N; 6.5; S, 5.0. Found: C, 48.3; H, 4.1; N,6.2; S, 4.9%. IR: m(N–H) 3437m, m(C@N) 1535m, m(Pd–Cl) 303m cm�1. 1H NMR (d ppm, J Hz): 4.22 (s, 5H,C5H5), 4.45 (t, 2H, H3/H4, N = 3.4), 4.95 (t, 2H, H2/H5,N = 3.4), 4.65 (s, 2H, NH2), 8.34 (d, 1H, HC@N,4J(PH) = 4.2). 31P–{1H} NMR (d ppm) 26.5s.

4.10. [Pd{(g5-C5H5)Fe(g5-C5H3)C(H)@NN@C(S)NH2}-

(Cl){P(C6D5)3}] (5a)

Yield: 59.5%. Anal. Calc. for C30H12D15ClFeN3PPdS:C, 51.1; H, 6.0; N, 6.0; S, 4.6. Found: C, 51.4; H, 5.9; N,5.4; S, 4.9%. IR: m(N–H) 3445m, m(C@N) 1534m, m(Pd–Cl) 302m cm�1. 1H NMR (d ppm, J Hz): 4.24 (s, 5H,C5H5), 4.46 (t, 2H, H3/H4, N = 3.4), 4.96 (t, 2H, H2/H5,N = 3.4), 4.69 (s, 2H, NH2), 8.41 (d, 1H, HC@N,4J(PH) = 4.2). 31P–{1H} NMR (d ppm) 26.0s.

4.11. [Pd{(g5-C5H5)Fe(g5-C5H3)C(H)@NN@C(S)NH-

Me}(Cl)(PPh3)] (4b)

Yield: 61.3%. Anal. Calc. for C31H29ClFeN3PPdS: C,52.9; H, 4.2; N, 6.0; S, 4.6. Found: C, 53.4; H, 3.9; N,5.6; S, 4.3%. IR: m(N–H) 3422m, m(C@N) 1596m, m(Pd–Cl) 324m cm�1. 1H NMR (d ppm, J Hz): 2.97 (d, 3H,NHMe, 3J(HMe) = 4.9), 3.95 (b, 1H, NHMe), 4.22 (s,5H, C5H5), 4.45 (t, 2H, H3/H4, N = 3.8), 5.00 (t, 2H,H2/H5, N = 3.8), 3.95 (b, 1H, NHMe), 8.41 (d, 1H,HC@N, 4J(PH) = 4.1). 31P–{1H} NMR (d ppm) 23.3s.

M. Marino et al. / Polyhedron 25 (2006) 1449–1456 1455

4.12. [Pd{(g5-C5H5)Fe(g5-C5H3)C(H)@NN@C(S)NH-

Me}(Cl)(PPh2Et)] (5b)

Yield: 63.8%. Anal. Calc. for C27H29ClFeN3PPdS: C,49.4; H, 4.5; N, 6.4; S, 4.9. Found: C, 50.0; H, 4.7; N,6.1; S, 5.1%. IR: m(N–H) 3423m, m(C@N) 1592m, m(Pd–Cl) 299m cm�1. 1H NMR (d ppm, J Hz): 3.00 (d, 3H,NHMe, 3J(HMe) = 4.6), 3.88 (b, 1H, NHMe), 4.20 (s,5H, C5H5), 4.44 (t, 2H, H3/H4, N = 3.8), 4.99 (t, 2H,H2/H5, N = 3.8), 8.34 (d, 1H, HC@N, 4J(PH) = 3.7).31P–{1H} NMR (d ppm) 26.5s.

4.13. [Pd{(g5-C5H5)Fe(g5-C5H3)C(H)@NN@C(S)NH-

Me}(Cl){P(C6D5)3}] (6b)

Yield: 57.4%. Anal. Calc. for C31H14D15ClFeN3PPdS:C, 51.8; H, 6.2; N, 5.8; S, 4.5. Found: C, 51.8; H, 5.9; N,5.6; S, 3.9%. IR: m(N–H) 3428s, m(C@N) 1593m, m(Pd–Cl)278w cm�1. 1H NMR (d ppm, J Hz): 2.85 (d, 3H, NHMe,3J(HMe) = 5.1), 4.21 (s, 5H, C5H5), 4.31 (t, 2H, H3/H4,N = 3.8), 4.53 (t, 2H, H2/H5, N = 3.8), 5.02 (b, 1H,NHMe), 8.78 (d, 1H, HC@N, 4J(PH) = 2.2). 31P–{1H}NMR (d ppm) 25.7s.

4.14. X-ray crystallographic study2

Three-dimensional, room temperature X-ray data werecollected in the range 1.86 < h < 26.43� (2a), 1.33 <h < 26.44� (2b) on a Bruker CCD diffractometer by theomega scan method. Reflections were measured from ahemisphere of data collected of frames each covering 0.3degrees in omega. The 13790 (2a), 16756 (2b) reflectionsmeasured were corrected for Lorentz and polarisationeffects and for absorption using a semi-empirical correctionbased on symmetry-equivalent and repeated reflections.The structure was solved by direct methods and refined byfull matrix least unique data, 307 (2a) 339 (2b) parameters,with allowance for the thermal anisotropy of all non hydro-gen atoms. Hydrogen atoms were included in calculatedpositions and refined in riding mode. The refinement wascarried out taking into account the minor components ofthe disorder. Minimum and maximum final electron density0.748 and �0.502 (2a), 0.635 and �0.686 (2b) e A�3. Thestructure solution and refinement were carried out usingthe program package SHELX-97 [33].

Acknowledgements

We thank the DGESIC (Ministerio de Ciencia y Tec-nologıa) Proyecto BQU2002-04533-C02-01 for financial

2 Crystallographic data (excluding structure factors) for the structuresreported in this paper have been deposited with the Cambridge Crystal-lographic Data Centre as supplementary publication numbers 279562 (2a)and 279563 (2b). Copies of the data can be obtained free of charge onapplication to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [fax:(internat.) +44 1223/336 033; e-mail: deposit@ccdc.cam.ac.uk].

support, and the Xunta de Galicia, incentive PGI-DIT03PXIC20912PN, for financial support.

Appendix A. Supplementary data

Crystallographic data (excluding structure factors) forthe structures reported in this paper have been depositedwith the Cambridge Crystallographic Data Centre as sup-plementary publication numbers 279562 (2a) and 279563(2b). Copies of the data can be obtained free of chargeon application to CCDC, 12 Union Road, CambridgeCB2 1EZ, UK. Supplementary data associated with thisarticle can be found, in the online version, atdoi:10.1016/j.poly.2005.10.003.

References

[1] (a) I. Omae, Organometallic Intramolecular Coordination Com-pounds, Elsevier, Amsterdam, 1986;(b) O.A. Dunina, V.M. Zalewskaya, V.M. Potapov, Russ. Chem.Rev. 57 (1988) 250;(c) I. Omae, Coord. Chem. Rev. 83 (1988) 137, and references therein;(d) A.D. Ryabov, Chem. Rev. 90 (1990) 403;(e) J. Dupont, C.S. Consorti, J. Spencer, Chem. Rev. 105 (2005)2527.

[2] (a) L. Main, B.K. Nicholson, Adv. Met.-Org. Chem. 3 (1994) 1;(b) J. Spencer, M. Pfeffer, Adv. Met.-Org. Chem. 6 (1998) 103.

[3] (a) J. Dupont, M. Pfeffer, J. Spencer, Eur. J. Inorg. Chem. (2001)1917;(b) L. Botella, C. Najera, Angew. Chem., Int. Ed. 41 (2002) 179.

[4] S.B. Wild, Coord. Chem. Rev. 166 (1997) 291.[5] C.M. Che, W.F. Fu, S.W. Lai, Y.J. Hou, Y.I. Liu, Chem. Commun.

(2003) 118.[6] (a) V.W.W. Yam, K.M.C. Wong, N.J. Zhu, J. Am. Chem. Soc. 124

(2002) 6506;(b) W. Lu, B.X. Mi, M.C.W. Chan, Z. Hul, N. Zhu, S.T. Lee, C.M.Che, Chem. Commun. (2002) 206;(c) C. Adachi, M.A. Baldo, S.R. Forrest, S. Lamanski, M.L.Thompson, R.C. Kwong, Appl. Phys. Lett. 78 (2001) 1622.

[7] (a) T.J. Kealy, P.L. Pauson, Nature 186 (1951) 1039;(b) G. Wilkinson, M. Rosenblum, M.C. Whiting, R.B. Woodward,J. Am. Chem. Soc. 74 (1952) 2125;(c) E.O. Fischer, W. Pfab, Z. Naturfosch. B 7 (1952) 377.

[8] (a) For a comprehensive overview of ferrocene and metallocenechemistry, see: A. Togni, R.L. Halterman (Eds.), Metallocenes,Wiley–VCH, Weinheim, Germany, 1998;(b) N.J. Long, Metallocenes: An Introduction to Sandwich Com-plexes, Blackwell, Oxford, 1998.

[9] (a) A. Togni, T. Hayashi (Eds.), Ferrocenes: Homogeneus Catalysis.Organic Synthesis. Materials Science, VCH, Weinheim, Germany,1995;(b) C.S. Slone, D.A. Weinberger, C.A. Mirhin, Prog. Inorg. Chem.48 (1999) 233;(c) R.C.J. Atkinson, V.C. Gibson, N.J. Long, Chem. Soc. Rev. 33(2004) 313.

[10] (a) For recent advances in cyclometallated [C(sp2/ferrocene),N]ligands see, for instance: C. Lopez, R. Bosque, J. Arias, E.Evangelio, X. Solans, M. Font-Bardıa, J. Organomet. Chem. 672(2003) 34;(b) J.M. Vila, E. Gayoso, T. Pereira, M. Marino, J. Martınez, J.J.Fernandez, A. Fernandez, M. Lopez-Torres, J. Organomet. Chem.637–639 (2001) 577;(c) V.V. Dunina, O.N. Gorunova, M.V. Livantsov, Y.K. Grishin,L.G. Kuz�mina, N.A. Kataeva, A.V. Churakov, Tetrahedron:Asymm. 11 (2000) 3967.

1456 M. Marino et al. / Polyhedron 25 (2006) 1449–1456

[11] (a) Y. Wu, J. Hou, H. Yun, X. Cui, R. Yuan, J. Organomet. Chem.637–639 (2001) 793;(b) F. Yang, Y. Zhang, R. Zheng, J. Tang, M. He, J. Organomet.Chem. 651 (2002) 146.

[12] L.E. Overwan, T.P. Remarchuk, J. Am. Chem. Soc. 124 (2002)12.

[13] X.L. Cui, Y.J. Wu, L.R. Yang, Chin. Chem. Lett. 10 (1999) 127.[14] (a) L. Xu, Q.S. Li, X. Jia, X. Huang, R. Wang, Z. Zhou, Z. Lin,

A.S.C. Chen, Chem. Commun. (2003) 1666;(b) J. Bravo, C. Cativela, R. Navarro, E.P. Urriolabeitia, J.Organomet. Chem. 650 (2002) 157;(c) A. Fernandez, P. Urıa, J.J. Fernandez, M. Lopez-Torres, A.Suarez, D. Vazquez-Garcıa, M.T. Pereira, J.M. Vila, J. Organomet.Chem. 620 (2001) 8.

[15] (a) C. Lopez, A. Caubet, S. Perez, X. Solans, M. Font-Bardia, J.Organomet. Chem. 681 (2003) 82;(b) I. Pal, S. Dutta, F. Basuli, S. Goverdhan, S.M. Peng, G.H. Lee,S. Bhattacharya, Inorg. Chem. 42 (2003) 4338;(c) A. Fernandez, D. Vazquez-Garcıa, J.J. Fernandez, M. Lopez-Torres, A. Suarez, S. Castro-Juiz, J.M. Vila, New. J. Chem. 26 (2002)398.

[16] (a) C. Lopez, S. Perez, X. Solans, M. Font-Bardia, J. Organomet.Chem. 650 (2002) 258;(b) X. Riera, A. Caubet, C. Lopez, V. Moreno, E. Freisinger, M.Willermann, B. Lippert, J. Organomet. Chem. 629 (2001) 97;(c) A. Fernandez, D. Vazquez-Garcia, J.J. Fernandez, M. Lopez-Torres, A. Suarez, S. Castro-Juiz, J.M. Ortigueira, J.M. Vila, New. J.Chem. 26 (2002) 105.

[17] (a) C. Lopez, S. Perez, X. Solans, M. Font-Bardia, J. Organomet.Chem. 690 (2005) 228;(b) A. Gonzalez, J.R. Granell, C. Lopez, J. Organomet. Chem. 637–639 (2001) 116;(c) C. Lopez, A. Caubet, S. Perez, X. Solans, M. Font-Bardia, J.Organomet. Chem. 651 (2002) 105;(d) S. Perez, C. Lopez, A. Caubet, X. Solans, M. Font-Bardia, J.Organomet. Chem. 689 (2004) 3184.

[18] (a) C. Lopez, A. Caubet, R. Bosque, X. Solans, M. Font-Bardia, J.Organomet. Chem. 645 (2002) 146;(b) S. Perez, C. Lopez, A. Caubet, R. Bosque, X. Solans, M. Font-Bardia, A. Roig, E. Molins, Organometallics 23 (2004) 224.

[19] A.A. Koridze, S.A. Kuklin, A.M. Sheloumov, F.M. Dolgushin, V.Y.Lagunova, I.I. Petukhova, M.C. Ezernitskaya, A.S. Peregudov, P.V.Petrovskii, E.V. Vorontsov, M. Baya, R. Poli, Organometallics 23(2004) 4585.

[20] J.M. Vila, E. Gayoso, M.T. Pereira, J.M. Ortigueira, G. Alberdi, M.Marino, R. Alvarez, A. Fernandez, Eur. J. Inorg. Chem. (2004) 2937.

[21] (a) J.M. Vila, M.T. Pereira, J.M. Ortigueira, M. Grana, D. Lata, A.Suarez, J.J. Fernandez, A. Fernandez, M. Lopez-Torres, H. Adams,J. Chem. Soc., Dalton Trans. (1999) 4193;(b) A. Amoedo, M. Grana, J. Martınez, T. Pereira, M. Lopez-Torres,A. Fernandez, J.J. Fernandez, J.M. Vila, Eur. J. Inorg. Chem. (2002)613;(c) A.G. Quiroga, J.M. Perez, I. Lopez-Solera, J.R. Masaguer, A.Luque, P. Roman, A. Edwards, C. Alonso, C. Navarro-Ranninger,J. Med. Chem. 41 (1998) 1399.

[22] J.S. Casas, M.V. Castano, M.C. Cifuentes, A. Sanchez, J. Sordo,Polyhedron 21 (2002) 1651.

[23] T.S. Lobana, A. Sanchez, J.S. Casas, A. Castineiras, J. Sordo, M.S.Gracıa-Tasende, E.M. Vazquez-Lopez, J. Chem. Soc. Dalton Trans.(1997) 4289.

[24] D.X. West, J.S. Ives, G.A. Bain, A.L. Liberta, J. Valdes-Martınez,K.H. Ebert, S. Hernandez-Ortega, Polyhedron 16 (1997) 1995.

[25] H. Onoue, I. Moritani, J. Organomet. Chem. 43 (1972) 431.[26] J.M. Vila, B.L. Shaw, J. Chem. Soc., Chem. Comm. (1987) 1778.[27] J. Vicente, J.A. Abad, A.D. Frankland, M.C. Ramirez de Arellano,

Chem. Eur. J. 5 (1999) 3067.[28] R. Ares, M. Lopez-Torres, A. Fernandez, M.T. Pereira, G. Alberdi,

D. Vazquez-Garcıa, J.J. Fernandez, J.M. Vila, J. Organomet. Chem.665 (2003) 76.

[29] F.H. Allen, O. Kennard, D.G. Watson, R. Taylor, J. Chem. Soc.,Dalton Trans. (1989) S1.

[30] T. Suzuki, A. Morikawa, K. Kashiwabara, Bull. Chem. Soc. Jpn. 69(1996) 2539.

[31] A. Habtemariam, B. Watchman, B.S. Potter, R. Palmer, S. Parsons,A. Parkin, P.J. Sadler, J. Chem. Soc. Dalton Trans. (2001) 1306.

[32] W.L.F. Armarego, C. Chai, Purification of Laboratory Chemicals,fifth ed., Butterworth–Heinemann, Oxford, 2003.

[33] G.M. Sheldrick, SHELX-97, An Integrated System for Solving andRefining Crystal Structures from Diffraction Data, University ofGottingen, Germany, 1997.