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Polyhedron Vol. 15, No. 9, pp. 1575-1577, 1996 Copyright © 1996 Elsevier Science Ltd

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COMMUNICATION

SYNTHESIS AND X-RAY CRYSTAL STRUCTURE OF [(CsMes)Ru(P2N2)h[ZnCI4I "2H20

WAI-KWOK WONG* and YANG CHEN

Department of Chemistry, Hong Kong Baptist University, 224 Waterloo Road, Kowloon, Hong Kong

and

WING-TAK WONG*

Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong

(Received 8 September 1995 ; accepted 21 September 1995)

Abstract--The interaction of [(CsMes)Ru(CH3CN)3] + (generated in situ from the reaction of [(CsMes)RuC12]n with excess granular zinc in CH3CN) with one equivalent of N,N'-bis[o- (diphenylphosphino)benzylidene]ethylenediamine (P2N2) in CH3CN at room temperature gave [(C5Me5)Ru(P2N2)]2[ZnC14] • 2H20 in good yield (80%). The compound has been fully characterized by analytical, spectroscopic and X-ray diffraction methods.

We have been interested in the chemistry of di- iminodiphosphine ligands as these are polydentate ligands containing both phosphorus and nitrogen donor atoms which could behave as soft and hard bases, respectively, and act as bridging ligands for the preparation of heterometallic complexes with hard and soft metal centres. We have shown that these ligands exhibit a very rich coordination chem- istry and can behave as bridging, bi-, tri- and tetra

* Authors to whom correspondence should be addressed. t [(CsMes)Ru(P2N2)]2[ZnC14]'2H20. Dark red crys-

tals, m.p. 220-223°C. Found: C, 62.2; H, 5.1 ; N, 2.8. Calc. for C,00HI02N402P4C14ZnRu2 : C, 62.4; H, 5.3 ; N, 2.9%. IR (cm -1, in KBr): 3440 br,s, 3052 m, 2902 m, 1626 m, 1584 w, 1476 m 1432 s, 1384 w, 1294 w, 1268 w, 1218 w, 1090 m, 1070 w, 1022 m, 920 w, 746 s, 694 vs, 508 s, 490 m. 3'p{IH} NMR (CDCI3): uncoordinated PPh2 group, 6 -15.6(s) ppm; coordinated PPh2 group,

43.6(s) ppm. ~H NMR (CDCI3) : - - C H = N - - proton of uncoordinated benzylidene, ~ 9.80 (IH, m) ppm; - - C H = N - - proton of coordinated benzylidene, 6 8.18 (1H, m) ppm; phenyl protons, 6 6.80-7.80 (28H, br, m) ppm ; --NCHzCH2N-- protons, 6 3.90-4.20 (4H, br, m) ppm ; H20 protons, 6 2.01 (2H, s) ppm ; CH3 protons, 6 1.09 (15H, s) ppm.

dentate ligands depending on the reaction conditions. 1-6 As a tridentate ligand, the di- iminodiphosphine ligand exhibits different modes of coordination towards different metal centres. The diiminodiphosphine ligands coordinate to the Group 6 metals (Cr, Mo) via the two imino groups and one of the phosphino groups, with one of the phosphino groups remaining uncoordinated, 2"6 and coordinate to the Group 11 metals (Cu, Ag) via the two phosphino groups and one of the two imino groups, only with one of the imino groups remain- ing uncoordinated. 4'6 In this communication, we report the preliminary study of the coordination mode of the diiminodiphosphine ligand N,N'-bis[o- (diphenylpho sphino) benzylidene]ethylenediamine (P2N2) toward ruthenium, a Group 8 metal.

When [CsMe5)Ru(CH3CN)3 ] +, generated in situ from the reaction of [(CsMes)RuCI2], with excess granular zinc in CH3CN, was treated with one equi- valent of P2N2 in CH3CN at room temperature for 12 h; work-up gave dark red crystals of stoi- chiometry [(CsMe5)Ru(P2N2)]2[ZnCI4] "2H20 (I) in good yield (80%) after recrystallization from a CH3CN-Et20 mixture.% The I R spectrum of I exhi- bits a v ( ~ N ) stretch at 1626 cm -1 for the imino groups. The 31p{lH} N M R spectrum of I exhibits

1575

1576

c(lo)

C~

C(5)

Communication

C(6)

C(7)

C(47) C(48)

C(49)

C(17)!_ C(18) C ( 2 3 ) ~ ( ~ ~RuS! _) c(5o)

C(22)~(21)C(13) k " C ( l l ~ @ C(32) P(2)

C(26)(a0"~J~ ~ C(12)

C(27)

c(28)

c(~) C(43)

".(30)

C(29)

Fig. 1. A perspective view of the molecular structure of the cation of [(CsMes)Ru(P2N2)MZnC14]'2H20. Selected bond lengths (~) and bond angles (°): Ru(I)--P(1), 2.307(5); Ru(1)--N(1), 2.05(2); Ru(1)--N(2), 2.16(1); Ru(1)--C(1), 2.21(2); Ru(1)--C(2), 2.25(2); Ru(1)--C(3), 2.20(2); Ru(1)--C(4), 2.18(3); Ru(1)--C(5), 2.23(2); N(1)--C(ll), 1.50(2); N(1)--C(13), 1.28(2); N(2)--C(12), 1.46(3); N(2)--C(32), 1.27(3); P(1)--Ru(1)--N(I), 78.9(5); P(1)--Ru(1)--N(2), 95.0(4); N(1)--Ru(1)--N(2), 79.0(6); N(1)--C(13)--C(14), 121(2);

N(1)--C(1 l)--C(12), 104(2); N(2)--C(32)--C(33), 133(2); N(2)--C(12)--C(1 l), 112(2).

C01)

C(42)

two singlets of relative intensity 1 : 1 at ~ - 15.6 and 43.6 ppm. The resonance at 6 43.6 ppm corresponds to a coordinated phosphorus and the resonance at 6 - 1 5 . 6 ppm corresponds to an uncoordinated

:~ Crystal data for RuZn0.sCsoH49N2P2C12" H20. Fw = 962.58, monoclinic, C2/c (No. 15), a = 28.185(6), b = 18.484(2), c=19.354(4) A,, fl=113.45(1) °, V= 9249.8(1) ~3, Z = 8, F(000) = 3960, Dc = 1.381 g cm -3, # = 78.23 cm -~. Crystal dimensions: 0.20 x 0.22 x 0.32 mm. Intensity data were collected on an Enraf-Nonius CAD-4 diffractometer with graphite monochromated Mo-K~ radiation (2 = 0.71073 ,~) using co-20 scans (20max = 40°)- The structure was solved by a combination of Patterson and difference Fourier techniques after an absorption correction (transmission factors 0.8094).999) was applied and refined by full-matrix least squares analysis to give R = 0.066, Rw = 0.079 for 1894 inde- pendent observed reflections [Io ~> 3cr(Io)]. Ru, Zn, P and C1 atoms were refined anisotropically and the rest of the atoms were refined isotropically. Hydrogen atoms were placed in their idealized positions and included in the calculations but not refined. All calculations were per- formed on a Silicon-Graphics computer using program package TeXan 7 from MSC.

phosphorus. This suggests that the P2N2 ligand behaves as a tridentate ligand, with one of its phos- phino groups remaining uncoordinated. This is fur- ther supported by the IH N M R spectrum of I, which exhibits a broad multiplet at 6 9.80 ppm, which corresponds to the - - C H - - N - - proton of the uncoordinated benzylidene, and a broad multi- plet at 6 8.18 ppm, which corresponds to the - - C H - - N - - proton of the coordinated benzyl- idene. The IH N M R spectrum of I also exhibits a singlet at 6 1.09 ppm for the methyl protons of the pentamethylcyclopentadienyl ring, indicating that the pentamethylcyclopentadienyl ring is bonded to the ruthenium metal in 05 fashion. Based on the above spectroscopic data, the following structure can be assigned to I.

Communication 1577

The structure of I was confirmed by an X-ray diffraction study.~ Crystals of stoichiometry [(CsMes)Ru(P2N2)]E[ZnC14]'2H20 suitable for X- ray diffraction study were grown by slow diffusion of diethyl ether into a concentrated solution of I in CH3CN. A perspective drawing and selected bond lengths and bond angles of I are shown in Fig. 1 and its caption. All bond lengths and bond angles are normal. The solid state structure of I is con- sistent with its spectroscopic data. The structure shows that the pentamethylcyclopentadienyl ring is bonded to the ruthenium metal in r/5 fashion with Ru- -C bond lengths ranging from 2.18(3) to 2.25(2) /~; the diiminodiphospine ligand acts as a tridentate ligand with one of the two phosphino groups and the two imino groups coordinated to the ruthenium metal and an uncoordinated phosphino group. Within the diiminodiphosphine ligand, the N(1)--C(13) and N(2)--C(32) bond lengths are 1.28(2) and 1.27(3) /~, respectively, and are in agreement with the ~ N bond distance.

The present study shows that the mode of coor- dination of the diiminodiphosphine as a tridentate ligand toward ruthenium metal is similar to that of Group 6 metals, i.e. having one of the two phos- phino groups and the two imino groups coor- dinated to the metal and the other phosphino group

remaining uncoordinated. We are in the process of studying the coordination mode of the diimino- diphosphine as a tridentate ligand toward other Group 8 metals to examine whether the above mode of coordination is a general trend for Group 8 metals.

Acknowledgements--W.-K. Wong thanks the Hong Kong Baptist University and the Hong Kong Research Grants Council for financial support. W.-T. Wong thanks the Hong Kong Research Grants Council and the University of Hong Kong for financial support.

REFERENCES

1. W.-K. Wong, J.-X. Gao, Z.-Y. Zhou and T. C. W. Mak, Polyhedron 1992, 11, 2965.

2. W.-K. Wong, J.-X. Gao and W. T. Wong, Polyhedron 1993, 12, 1647.

3. W.-K. Wong, J.-X. Gao, Z-Y. Zhou and T. C. W. Mak, Polyhedron 1993, 12, 1415.

4. W.-K. Wong, J.-X. Gao, W. T. Wong, W. C. Cheng and C. M. Che, J. Organomet. Chem. 1994, 471,277.

5. J.-X. Gao, H.-L. Wan, W. K. Wong, M. C. Tse and W. T. Wong, Polyhedron 1995, 15, 1241.

6. J. C. Jeffrey, T. B. Rauchfuss and P. A. Tucker, Inor 9. Chem. 1980, 19, 3306.

7. TeXan, Crystal Structure Analysis Package. Molec- ular Structure Corporation (1985, 1992).