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Janse van Rensburg, J. Marthinus

Meijboom, Reinout

Muller, Alfred

Roodt, Andreas

English

University of Johannesburg Institutional Repository

metal-organic papersActa Cryst. (2005). E61, m1741–m1743 doi:10.1107/S1600536805024967 Janse van Rensburg et al.  [Rh(C9H6NO)(C24H27O3P)(CO)] m1741Acta Crystallographica Section EStructure ReportsOnlineISSN 1600-5368Carbonyl(8-hydroxyquinolinato)[tris(2,6-dimethyl-phenyl)phosphite]rhodium(I)J. Marthinus Janse vanRensburg,a‡ Andreas Roodt,b*Alfred Mullerb and ReinoutMeijboombaDepartment of Chemistry, University ofJohannesburg, PO Box 524, Auckland Park,Johannesburg 2006, South Africa, andbDepartment of Chemistry, University of the FreeState, PO Box 339, Bloemfontein 9300, SouthAfrica‡ Current address: Department of Chemistry,University of the Free State, PO Box 339,Bloemfontein 9300, South Africa.Correspondence e-mail:roodta.sci@mail.uovs.ac.zaKey indicatorsSingle-crystal X-ray studyT = 293 KMean (C–C) = 0.007 A˚R factor = 0.046wR factor = 0.097Data-to-parameter ratio = 15.6For details of how these key indicators wereautomatically derived from the article, seehttp://journals.iucr.org/e.# 2005 International Union of CrystallographyPrinted in Great Britain – all rights reservedIn the title compound, [Rh(C9H6NO)(C24H27O3P)(CO)], themolecules pack in a tail-to-tail fashion, with a – stackingdistance of 3.76 (6) A˚, due to the steric effect of the phosphiteligand. The effective cone angle (E) for the phosphite ligandis 183.CommentPrevious work has been carried out on rhodium–phosphinecomplexes containing the bidentate ligand OX (OX = oxinate,8-hydroxyquinolinate in the present study), illustrating thecatalytic importance of the rhodium(I) square-planar moiety(Roth et al., 1971). In this type of complex, starting with the[Rh(OX)(CO)2] complexes, the different donor atoms of thebidentate ligand (OX) result in the displacement of thecarbonyl group trans to the stronger donor (less electro-negative) atom. This opens the possibility of determining therelative trans influence of the donor atoms. In 8-hydroxy-quinoline, the N atom has a larger trans influence, due to itsbetter -electron donor capability, compared with that of theO atom. This results in carbonyl displacement trans to the Natom, as shown by Leipoldt et al. (1981).The title compound, (I), reported here forms part of ourstudy of complexes of the type [Rh(OX)(CO)(ER3)], where E= P, As or Sb, and R = alkyl, aryl, alkoyl or aroyl. The Rh atomlies on a general position and is slightly displaced out of thecoordination plane (Fig. 1, Table 1) by 0.039 (1) A˚. In the five-membered chelate ring, the oxinate ligand has a small biteangle of 80.34 (13) and a C10—Rh—P bond angle of90.31 (13). This illustrates the distorted square-planar metalcoordination polyhedron. There is a slight distortion in theoxinate ligand, with a dihedral angle of 1.5 (2) between thetwo aromatic rings. There is further distortion observedbetween the bidentate oxinate backbone and the metal coor-dination plane, with a dihedral angle of 6.3 (1).The molecules of (I) pack in a tail-to-tail fashion, with a –stacking distance of 3.76 (6) A˚ (Fig. 2). This tail-to-tailstacking is not a result of metal–metal interactions [Rh  Rh =Received 29 July 2005Accepted 3 August 2005Online 12 August 20057.0 (1) A˚], but is due to the steric effect of the phosphiteligand.The steric behaviour of the ligand at the metal centre wasdetermined by calculating the cone angle, as describedpreviously by Tolman (1977) and Otto et al. (2000). For thecurrent structure, the actual Rh—P bond distance[2.1982 (13) A˚] was used, yielding the effective cone angleE.The substituents of the phosphite may have different orien-tations, resulting in variations in solid-state cone angles, asobserved by Ferguson et al. (1978), and may therefore notnecessarily be a true indication of the steric properties of thephosphite in solution compared with the solid state. Thebenzene rings of the tris(2,6-dimethylphenyl)phosphite ligandare arranged in such a way as to give an effective cone angleE = 183, which is comparable with that reported by Meij-boom et al. (2004) for the corresponding Vaska-type rhodiumcomplex.Bond distances, bite angles and the effective cone angle for(I) are compared with those of similar structures in Table 2.The steric contribution of the methyl groups on the phenylring of the tris(2,6-dimethylphenyl)phosphite ligand is clearlyillustrated by the 30 increase in the size of the cone anglecompared with that for the triphenylphosphine and thetriphenylphosphite ligand complexes. A reasonable correla-tion between the bond distances and angles for the quinolinerings is observed. The shorter Rh—P bonds for the phosphitecomplexes are a result of the phosphite being a weaker donor but a better  acceptor than the phosphine ligand,leading to a stronger bond.The comparable 1J(Rh—P) values of the triphenylphosphiteand tris(2,6-dimethylphenyl)phosphite complexes are indica-tions that the methyl groups on the benzene ring have little orno electronic influence. The significant difference in couplingconstants between phosphine and phosphite complexes (161versus ca 280 Hz, respectively) is assumed to be due to the -accepting nature of phosphites, leading to a correspondingsignificant shortening of the Rh—P bond (ca 2.26 versus2.19 A˚, respectively). The additional increase from entry 3 toentry 4 is due to the change from RhI to RhIII following CH3Ioxidative addition.Experimental[RhCl(CO)2]2 was prepared according to the literature method ofMcCleverty & Wilkinson (1990). P(OC8H9)3 was prepared by reac-tion of the corresponding tris(2,6-dimethylphenyl)phenol with PCl3in the presence of NEt3, similar to the synthesis of tris(2-butyl-penyl)phosphite (van Leeuwen & Roobeek, 1983). All otherchemicals and solvents were obtained from Sigma–Aldrich and usedas received. [Rh(OX)(CO)2] was synthesized by mixing solutions of8-hydroxyquinoline (50 mg, 0.344 mmol) in dimethylformamide(DMF; 1 ml) and [RhCl(CO)2]2 (64 mg, 0.164 mmol) in DMF (1 ml).Upon addition of ice–water (20 ml), the complex precipitated andwas filtered. Ligand substitution on the complex [Rh(OX)(CO)2] wasperformed by dissolving a quantity (20 mg, 0.065 mmol) in acetone(40 ml) followed by slow addition of P(OC8H9)3 (29 mg, 0.072 mmol)in acetone (2 ml) (yield 33.5 mg, 76%). Spectroscopic analysis:31P{H} NMR (CDCl3, 121.465 MHz, , p.p.m.): 124.1 [1J(Rh—P) =280 Hz]; IR (acetone): (CO) 1976 cm1; (KBr): (CO) 1980 cm1.metal-organic papersm1742 Janse van Rensburg et al.  [Rh(C9H6NO)(C24H27O3P)(CO)] Acta Cryst. (2005). E61, m1741–m1743Figure 1A view of (I), with the atom-numbering scheme. Displacement ellipsoidsare drawn at the 30% probability level. H atoms have been omitted forclarity. For the phenyl C atoms, the first digit indicates the ring numberand the second digit indicates the position of the atom in the ring.Figure 2The unit-cell contents of (I) viewed along the a axis, indicating the –stacking between the quinoline rings.Crystal data[Rh(C9H6NO)(C24H27O3P)(CO)]Mr = 669.49Triclinic, P1a = 10.580 (2) A˚b = 10.944 (2) A˚c = 13.886 (3) A˚ = 83.49 (3) = 75.25 (3) = 88.58 (3)V = 1545.0 (5) A˚3Z = 2Dx = 1.439 Mg m3Mo K radiationCell parameters from 925reflections = 5.5–45.9	 = 0.65 mm1T = 293 (2) KPlate, yellow0.36  0.12  0.07 mmData collectionBruker SMART CCD 1K area-detector diffractometer! scansAbsorption correction: multi-scan(SADABS; Bruker, 1998)Tmin = 0.801, Tmax = 0.9569255 measured reflections6014 independent reflections4122 reflections with I > 2(I)Rint = 0.030max = 26h = 12 ! 13k = 13 ! 13l = 17 ! 10RefinementRefinement on F 2R[F 2 > 2(F 2)] = 0.046wR(F 2) = 0.097S = 1.026014 reflections385 parametersH-atom parameters constrainedw = 1/[2(Fo2) + (0.0361P)2+ 0.3605P]where P = (Fo2 + 2Fc2)/3(/)max < 0.001max = 0.46 e A˚3min = 0.34 e A˚3Table 1Selected geometric parameters (A˚, ).Rh—C10 1.805 (5)Rh—O4 2.029 (3)Rh—N 2.091 (3)Rh—P 2.1982 (13)P—O2 1.596 (3)P—O3 1.597 (3)P—O1 1.610 (3)O5—C10 1.146 (5)C10—Rh—N 97.11 (16)O4—Rh—N 80.34 (13)C10—Rh—P 90.31 (13)O4—Rh—P 92.87 (8)O2—P—Rh 118.07 (11)O3—P—Rh 114.36 (10)O1—P—Rh 117.80 (11)O5—C10—Rh 177.6 (4)O1—P—Rh—C10 130.17 (18)O2—P—Rh—C10 107.74 (18)O3—P—Rh—C10 6.13 (17)Table 2Comparative geometrical data (A˚, , Hz) for [Rh(OX)(CO)(PR3)]complexes.R Rh—P Rh—N Rh—O N—Rh—O E1JRh—PO(2,6-DMP)a 2.198 (1) 2.091 (3) 2.029 (3) 80.3 (1) 183 280OPhb 2.186 (1) 2.097 (2) 2.022 (2) 80.8† 154 281Phc‡ 2.261 (2) 2.098 (9) 2.042 (5) 80.0 (3) 153 161Phd 2.317 (2) 2.084 (7) 2.037 (4) 81.2 (2) 153 163† Data extracted from the Cambridge Structural Database (Version 5.26; Allen, 2002);no s.u. values available. ‡ RhIII iodomethane oxidative addition product containingapical trans methyl and iodo ligands. References: (a) this work (2,6-DMP = 2,6-dimethylphenyl); (b) Simanko et al. (2000); (c) Leipoldt et al. (1981); (d) van Aswegen etal. (1991).The H atoms were positioned geometrically and refined using ariding model, with fixed C—H distances of 0.93 A˚ (CH) [Uiso(H) =1.2Ueq] and 0.96 A˚ (CH3) [Uiso(H) = 1.5Ueq].Data collection: SMART-NT (Bruker, 1998); cell refinement:SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus andXPREP (Bruker, 1999); program(s) used to solve structure: SIR97(Altomare et al., 1999); program(s) used to refine structure:SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND(Brandenburg & Berndt, 2001); software used to prepare material forpublication: WinGX (Farrugia, 1999).Financial assistance from the South African NationalResearch Foundation and the Research Funds of theUniversities of Johannesburg and the Free State is gratefullyacknowledged. The University of Witwatersrand (Professor D.Levendis and Dr D. G. Billing) is thanked for the use of itsdiffractometer. Part of this material is based on worksupported by the South African National Research Founda-tion [SA NRF, grant Nos. GUN 2053397 (University ofJohannesburg) and GUN 2038915 (University of the FreeState)]. Opinions, findings, conclusions or recommendationsexpressed in this material are those of the authors and do notnecessarily reflect the views of the NRF.ReferencesAllen, F. H. (2002). Acta Cryst. B58, 380–388.Altomare, A. Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C.,Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J.Appl. Cryst. 32, 115–119.Aswegen, K. G. van, Leipoldt, J. G., Potgieter, I. M., Lamprecht, G. J., Roodt,A. & Van Zyl, G. J. (1991). Transition Met. Chem. 16, 369–371.Brandenburg, K. & Berndt, M. (2001). DIAMOND. Release 2.1e. CrystalImpact GbR, Bonn, Germany.Bruker (1999). SAINT-Plus. Version 6.02 (including XPREP). Bruker AXSInc., Madison, Wisconsin, USA.Bruker (1998). SMART-NT (Version 5.050) and SADABS (Version 2004/1).Bruker AXS Inc., Madison, Wisconsin, USA.Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.Ferguson, G., Roberts, P. J., Alyea, E. C. & Khan, M. (1978). Inorg. Chem. 17,2965–2967.Leeuwen, P. W. N. M. van & Roobeek, C. F. (1983). J. Organomet. Chem. 258,343–350.Leipoldt, J. G., Basson, S. S. & Dennis, C. R. (1981). Inorg. Chim. Acta, 50, 121–124.McCleverty, J. A. & Wilkinson, G. (1990). Inorg. Synth. 28, 84–86.Meijboom, R., Muller, A. & Roodt, A. (2004). Acta Cryst. E60, m455–m457.Otto, S., Roodt, A. & Smith, J. (2000). Inorg. Chim. Acta, 303, 295–299.Roth, J. F., Craddock, J. H., Hershman, A. & Paulik, F. E. (1971). Chem.Technol. pp. 600–605.Sheldrick, G. M. (1997). SHELXL97. University of Go¨ttingen, Germany.Simanko, W., Mereiter, K., Schmid, R., Kirchner, K., Trzeciak, A. M. &Ziolkowski, J. J. (2000). J. Organomet. Chem. 602, 59–64.Tolman, C. A. (1977). Chem. Rev. 77, 313–348.metal-organic papersActa Cryst. (2005). E61, m1741–m1743 Janse van Rensburg et al.  [Rh(C9H6NO)(C24H27O3P)(CO)] m1743

Carbonyl(8-hydroxyquinolinato)[tris(2,6-dimethylphenyl) phosphite]rhodium(I)

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Carbonyl(8-hydroxyquinolinato)[tris(2,6-dimethylphenyl) phosphite]rhodium(I)

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