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Meijboom, Reinout

Muller, Alfred

Roodt, Andreas

English

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metal-organic papersActa Cryst. (2004). E60, m1071±m1073 DOI: 10.1107/S1600536804015594 Reinout Meijboom et al.  [Rh(C21H21O3P)2Cl(CO)] m1071Acta Crystallographica Section EStructure ReportsOnlineISSN 1600-5368trans-Carbonylchlorobis[tris(2-methyl-phenyl)phosphito]rhodium(I)Reinout Meijboom, Alfred Mullerand Andreas Roodt*Department of Chemistry and Biochemistry,Rand Afrikaans University, Auckland Park,Johannesburg, South Africa 2006Correspondence e-mail: aroo@rau.ac.zaKey indicatorsSingle-crystal X-ray studyT = 292 KMean (C±C) = 0.005 AÊDisorder in main residueR factor = 0.040wR factor = 0.093Data-to-parameter ratio = 19.0For details of how these key indicators wereautomatically derived from the article, seehttp://journals.iucr.org/e.# 2004 International Union of CrystallographyPrinted in Great Britain ± all rights reservedThe title compound, [Rh{P(OC7H7)3}2Cl(CO)], whereP(OC7H7)3 is tris(2-methylphenyl)phosphite, crystallizesdisordered over an inversion centre. Important geometricalparameters are RhÐP = 2.2905 (9) AÊ , RhÐCl = 2.402 (4) AÊ ,RhÐC = 1.764 (10) AÊ , and CÐRhÐCl = 177.7 (5), PÐRhÐCl = 85.84 (12) and RhÐC O = 174.7 (15). The effectivecone angle for the phosphite ligand was calculated to be 167.CommentSymmetrical square-planar complexes of Rh, Ir, Pd and Ptoften crystallize with the metal atom on a crystallographiccentre of symmetry, thus imposing a disordered packingarrangement (Otto, 2001; Otto et al., 2000; Chen et al., 1991;Kuwabara & Bau, 1994). The present study is part of anongoing investigation into determining which factors govern adisordered packing mode in Vaska-type complexes, i.e. trans-[M(CO)Cl(AX3)2] (M = Rh, Ir; A = group 15 donor atom P,As, Sb; X = alkyl, aryl, aroyl, etc.; Roodt et al., 2003). Thecurrent study reports the structure of trans-carbonylchloro-bis[tris(2-methylphenyl)phosphito]rhodium(I), (I), one of thefew phosphite-containing Vaska-type structures known to date[Cambridge Structural Database (CSD), Version 5.25, January2004 update; Allen, 2002].The title compound crystallizes as an independent moleculelying on an inversion centre, resulting in statistical disorder ofthe ClÐRhÐCO moiety. The coordination around the Rhatom shows a slightly distorted square-planar arrangement(Fig. 1 and Table 1).The most widely used method for determining ligand stericbehaviour at a metal centre is by calculating the cone angle, asdescribed previously (Tolman, 1977; Otto et al., 2000). For thisstudy, actual MÐP bond distances were used, yielding effec-tive cone angles (E). The substituents of the phosphite mayhave different orientations, resulting in variations in coneangle sizes, as observed by Ferguson et al. (1978), and may notnecessarily be a true indication of the steric properties of thephosphite in solution compared with the solid state. The valueof 167 obtained for tris(2-methylphenyl)phosphite is smallerthan those for the few other similar structures known to date(Table 2). This is due to the smaller/fewer substituents on theReceived 18 June 2004Accepted 25 June 2004Online 9 July 2004benzene rings for the title compound, introducing more ¯ex-ibility in the aroyl substituents.Table 2 also compares bond distances of the other similarcomplexes, and shorter MÐP bond distances are observed inthe phosphites than, for example, for the tribenzylphosphineanalogue (Muller et al., 2002), also manifested in the 1JRhÐPcoupling of 212 Hz for (I) compared with 124 Hz for thephosphine complex. The 1JRhÐP coupling is in good agreementwith the 1JRhÐP of 214 Hz for the tris(2,6-dimethylphenyl)-phosphite complex reported earlier (Meijboom et al., 2004).This may be indicative that additional ortho-methyl groups onthe benzene rings have little or no effect, other than stericcontribution; moreover, the difference in coupling constantsbetween phosphite and phosphine complexes is probably dueto the electron-withdrawing nature of phosphites, whichenhances  back-bonding between the metal and the P atomand, as a result, weakens the MÐCl bond.Interesting to note is the difference in values of (CO) forthe solid and solution states of the title compound. Thisdifference may be the result of packing in the unit cell, whichslightly distorts the RhÐC O angle (Table 1).Experimental[RhCl(CO)2]2 was prepared according to the method described byMcCleverty & Wilkinson (1990), while P(OC7H7)3 was prepared byreaction of 2-methylphenol with PCl3 in the presence of NEt3,analogous to the synthesis of tris(2-butylpenyl)phosphite (VanLeeuwen & Robeck, 1983). All other chemicals and solvents wereobtained from Sigma±Aldrich and used as received. A solution ofP(OC7H7)3 (110 mg, 0.312 mmol) in pentane (1.0 ml) was addedslowly to a yellow solution of [RhCl(CO)2]2 (30 mg, 0.077 mmol) inpentane (1.0 ml). Gas evolution was observed immediately and thesolution turned lighter in colour while a precipitate formed. Thesupernatant liquid was decanted and the solids were washed withpentane (3 2 ml) to leave the pure title compound. Crystals suitablefor X-ray analysis were grown from CH2Cl2 (yield: 88 mg, 66%; m.p.398 K). 1H NMR (CDCl3, 300 MHz, p.p.m.): 7.35 (6H, m, J = 4.5 Hz,ArH), 7.11 (6H, m, J = 4.7 Hz, ArH), 7.03 (12H, m, ArH), 2.10 (18H,s, CH3);13C{H} NMR (CDCl3, 75.45 MHz, p.p.m.): 149.59, 131.30,130.13, 126.54, 124.75, 120.37, 16.53; 31P{H} NMR (CDCl3,121.42 MHz, p.p.m.): 114.42 (d, 1J(RhÐP) = 212 Hz); IR (CH2Cl2)(CO): 2011 cmÿ1; (KBr) (CO): 1999 cmÿ1; UV±Vis (CH2Cl2) max:267.3 (100), 358.0 (40%) nm.Crystal data[Rh(C21H21O3P)2Cl(CO)]Mr = 871.07Triclinic, P1a = 8.1871 (16) AÊb = 10.785 (2) AÊc = 13.101 (3) AÊ = 102.12 (3) = 104.65 (3) = 102.46 (3)V = 1049.1 (5) AÊ 3Z = 1Dx = 1.379 Mg mÿ3Mo K radiationCell parameters from 828re¯ections = 2.7±24.3 = 0.59 mmÿ1T = 292 (2) KPlate, yellow0.48  0.22  0.11 mmData collectionBruker SMART 1K CCDdiffractometer! scansAbsorption correction: multi-scan(SADABS; Bruker, 1998)Tmin = 0.764, Tmax = 0.9387011 measured re¯ections4966 independent re¯ections3453 re¯ections with I > 2(I)Rint = 0.019max = 28.3h = ÿ10! 10k = ÿ14! 10l = ÿ15! 17Re®nementRe®nement on F 2R[F 2 > 2(F 2)]= 0.040wR(F 2) = 0.093S = 1.024966 re¯ections262 parametersH-atom parameters constrainedw = 1/[2(Fo2) + (0.0405P)2+ 0.1712P]where P = (Fo2 + 2Fc2)/3(/)max = 0.001max = 0.30 e AÊÿ3min = ÿ0.45 e AÊ ÿ3Table 1Selected geometric parameters (AÊ , ).RhÐC 1.764 (10)RhÐP 2.2905 (9)RhÐCl 2.402 (4)PÐO2 1.588 (2)PÐO1 1.599 (2)PÐO3 1.6041 (19)O1ÐC11 1.412 (3)CÐRhÐP 92.1 (4)PiÐRhÐP 180CiÐRhÐCl 177.7 (5)OÐCÐRh 174.7 (15)CÐRhÐPÐO1 116.7 (5)CÐRhÐPÐO2 ÿ6.9 (5)CÐRhÐPÐO3 ÿ131.4 (5)Symmetry code: (i) 1ÿ x;ÿy; 1ÿ z.Table 2Comparative geometrical data (AÊ ,) for trans-[M(CO)Cl(PX3)2]complexes.X MÐP MÐCl PÐMÐP ClÐMÐC EO(2MP)a 2.2905 (9) 2.402 (4) 180 177.7 (5) 167O(2,6DMP)b 2.3097 (7) 2.380 (3) 180 179.2 (6) 1822.2995 (7) 2.379 (3) 180 178.3 (5) 182O(2tBP)c 2.286 2.370 180 175.85 181Bzd 2.3164 (15) 2.3654 (15) 177.67 (6) 178.55 (17) 1702.3156 (16) 172Notes: (a) this work (2MP = 2-methylphenyl); (b) Meijboom et al. (2004) (2,6DMP = 2,6-dimethylphenyl); (c) FernaÂndez et al. (1998) (2tBP = 2-tert-butylphenyl); data extractedfrom Cambridge Structural Database (Allen, 2002), no s.u. values available; (d) Muller etal. (2002) (Bz = benzyl).metal-organic papersm1072 Reinout Meijboom et al.  [Rh(C21H21O3P)2Cl(CO)] Acta Cryst. (2004). E60, m1071±m1073Figure 1The structure of (I), showing the 50% statistical disorder of the ClÐRhÐCO moiety. Displacement ellipsoids are drawn at the 30% probabilitylevel. H atoms have been omitted for clarity. For the C atoms, the ®rstdigit indicates ring number and the second digit indicates the position ofthe atom in the ring. Atom P0 is generated by the symmetry operation(1 ÿ x, ÿy, 1 ÿ z).The aromatic and methyl H atoms were placed in geometricallyidealized positions (CÐH = 0.93±0.96 AÊ ) and constrained to ride ontheir parent atoms, with Uiso(H) = 1.2Ueq(C) and 1.5Ueq(C), respec-tively. A rotating group model was used for two methyl groups.Data collection: SMART-NT (Bruker, 1998); cell re®nement: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 re®ne structure:SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND(Brandenburg, 2001); software used to prepare material for publi-cation: WinGX (Farrugia, 1999).Financial assistance from the South African NationalResearch Foundation, SASOL and the Research Fund ofRAU is gratefully acknowledged. The University of theWitwatersrand (Professor D. Levendis and Dr D. Billing) isthanked for the use of its diffractometer. Part of this materialis based on work supported by the South African NationalResearch Foundation under grant number GUN 2053397.Opinions, ®ndings, conclusions or recommendations expressedin this material are those of the authors and do not necessarilyre¯ect the views of the NRF.ReferencesAllen, F. H. (2002). Acta Cryst. B58, 380±388.Altomare, A., Burla, M. C., Camalli, M., Cascarano, G., Giacovazzo, C.,Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J.Appl. Cryst. 32, 115±119.Brandenburg, K. (2001). DIAMOND. Release 2.1e. Crystal Impact GbR,Bonn, Germany.Bruker (1998). SADABS (Version 2004/1) and SMART-NT (Version 5.050).Bruker AXS Inc., Madison, Wisconsin, USA.Bruker (1999). SAINT-Plus. Version 6.02 (including XPREP). Bruker AXSInc., Madison, Wisconsin, USA.Chen, Y., Wang, J. & Wang, Y. (1991). Acta Cryst. C47, 2441±2442.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.FernaÂndez, E., Ruiz, A., Claver, C., Castillon, S., Polo, A. Piniella, J. F. &Alvarez-Larena, A. (1998). Organometallics, 17, 2857±2864.Kuwabara, E. & Bau, R. (1994). Acta Cryst. C50, 1409±1411.McCleverty, J. A. & Wilkinson, G. (1990). Inorg. Synth. 28, 84±86.Meijboom, R., Muller, A. & Roodt, A. (2004). Acta Cryst. E60, m455±m457.Muller, A. J., Roodt, A., Otto, S., Oskarsson, AÊ . & Yong, S. (2002). Acta Cryst.E58, m715±717.Otto, S. (2001). Acta Cryst. C57, 793±795.Otto, S., Roodt, A. & Smith, J. (2000). Inorg. Chim. Acta, 303, 295±299.Roodt, A., Otto, S. & Steyl, G. (2003). Coord. Chem. Rev. 245, 121±137.Sheldrick, G. M. (1997). SHELXL97. University of GoÈ ttingen, Germany.Tolman, C. A. (1977). Chem. Rev. 77, 313±348.Van Leeuwen, P. W. N. M. & Robeck, C. F. (1983). J. Organomet. Chem. 258,343±350.metal-organic papersActa Cryst. (2004). E60, m1071±m1073 Reinout Meijboom et al.  [Rh(C21H21O3P)2Cl(CO)] m1073

trans-Carbonylchlorobis[tris(2-methyl- phenyl)phosphito]rhodium(I)

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trans-Carbonylchlorobis[tris(2-methyl- phenyl)phosphito]rhodium(I)

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