Organometallics 1996,14, 3649-3658
3649
Homoleptic Actinide Complexes with Chelating Diphosphinophosphido Ligands: New Mode of Reactivity with Carbon Monoxide and the X-ray Crystal Structure of U(P(CHzCH2PMe2)2}4 Peter G. Edwards,* Julian S. Parry, and Paul W. Read Department of Chemistry, University of Wales Cardiff, P.O. Box 912, Cardiff, C F l 3TB, U.K. Received September 14, 1994@ The tetrakis(dialkylphosphid0)complexes M(P(CH2CHzPMe2)2}4(M = Th, U)are isolated in high yield from the reaction of MC14 with 4 mol equiv of (Li+ or K+)-P(CH2CHzPMe& ((Li/K)PPP). The uranium and thorium compounds are isostructural, although the thorium compound exhibits dimorphism. Detailed shape analysis indicates the structures of the three tetraphosphides conform to triangulated dodecahedra distorted toward bicapped trigonal prisms. The thorium compound is shown to be labile, exhibiting facile exchange of coordinated with uncoordinated tertiary phosphine functions, by 31P{rH}NMR spectroscopy. The thorium compound reacts readily with CO to give a unique double-insertion product where CO is incorporated into a diphosphacarbinol (diphospha secondary alcohol) derivative with two phosphido phosphorus atoms becoming bonded to the inserted carbon atom and the new P2CO unit being v3-bonded to thorium. Structural and spectroscopic data indicate a reduction in C - 0 bond order from 3 to 1 upon insertion. Hydrolysis liberates the free diphospha secondary alcohol, which is unstable with respect to P-C cleavage and aldehyde formation under mass-spectroscopic conditions. Alkenes with vinylic protons and phenols also react with the thorium tetraphosphide, which eliminates HPPP. The new compounds were characterized by analytical and spectroscopic techniques and by X-ray crystallography for the uranium complex. Introduction
There are very few authentic dialkylphosphido complexes of the actinides known. Prior to this study, the only other well-characterized examples of actinide dialkylphosphides reported were those of the type Cp2Th(PR2)2 (Cp = C5H5; R = alkylll and CpzTh(PRz)zNi(C0)z (R = alkyl).2 The application of potentially multidentate amido and phosphido ligands containing ancillary neutral donors has been successful in stabilizing new classes of complexes with transition and lanthanide metal^,^ with one recent example for actinides.3b In this paper we discuss the synthesis, characterization, and structural analysis of the first homoleptic actinide phosphido complexes and report on their reactivities with carbon monoxide. We have recently reported preliminary results of the application of -P(CH&Hz-
* To whom correspondence
should be addressed. Abstract published in Advance ACS Abstracts, June 15, 1995. (1)Wrobleski, D. A,; Ryan, R. R.; Wasserman, H. J.; Salazar, K. V.; Paine, R. T.; Moody, D. C.Organometallics 1986,5,90. (2)Ryan, R. R.; Paine, R. T.; Moody, D. C. J . A m . Chem. SOC.1985, 107, 501. (3)(a) Wills, A. R.; Edwards, P. G. J . Chem. SOC.,Dalton Trans. 1989,1253. Danopoulos, A. A.; Edwards, P. G. Polyhedron 1989,8, 1339. Wills, A. R.; Edwards, P. G.; Harman, M.; Hursthouse, M. B. Polyhedron 1989,1457. Al-Soudani, A.-R.; Batsanov, A,; Edwards, P. G.; Howard, J. A. K. J . Chem. SOC.,Dalton Trans. 1994,987. Fryzuk, M. D.; Haddad, T. S.; Berg, D. J . Coord. Chem. Rev. 1990,99,137.(b) Coles, S. J.; Edwards, P. G.; Hursthouse, M. B.; Read, P. W. J . Chem. SOC.,Chem. Commun. 1994,1967. (c) Edwards, P. G.; Howard, J. A. K.; Parry, J. S.;Al-Soudani, A.-R. J . Chem. SOC.,Chem. Commun. 1991, 1385. (d) Danopoulos, A. A.; Edwards, P. G.; Harman, M.; Hursthouse, M. B.; Parry, J. S. J . Chem. SOC.,Dalton Trans. 1994, 977. (e) Edwards, P. G.; Read, P. W.; Hursthouse, M. B.; Malik, K. M. A. J . Chem. SOC.,Dalton Trans. 1994,971. (4) Edwards, P. G.; Harman, M.; Hursthouse, M. B.; Parry, J. S. J . Chem. SOC.,Chem. Commun. 1992,1469.
c7
C31
Figure 1. Molecular structure of U{ P(CHzCHzPMedz}4 (1).
PMe2)2 (PPP) to the synthesis of thorium phosphides4 and reactions with carbon m~noxide.~
@
Results and Discussion
The reactions discussed below and representations of the structures of the actinide compounds are collected in Scheme 1. U{P(CH2CH2PMe2)2}4 (1). The addition of 4 mol equiv of a standard solution of KPPP to UCl4 in PhMe/ THF at -80 "C generates black solutions from which black crystals can be isolated in good yield from light petroleum ether. Interestingly, the interaction of 3 mol equiv of a standard solution of KPPP with UC13(THF), (5) Edwards, P. G . ;Hursthouse, M. B.; Malik, K. M. A.; Parry, J . S. J . Chem. SOC.,Chem. Commun. 1994,1249.
0276-733319512314-3649$09.00/0 0 1995 American Chemical Society
3660 Organometallics, Vol. 14, No. 8, 1995
Edwards et al.
Scheme 1. Preparation and Reactions of Actinide Phosphides, M(P(CH&HaPMes)2}4 (M = Th, U) 8
M e e - 0 2 M@ M=b,K
I
co
affords an identical black crystalline material. The reaction of LiPPP with U c 4 and UCldTHF), gives the same compound in much lower yield; the lower solubility of potassium chloride vs that of lithium chloride in hydrocarbons and THF may help drive the reaction t o a cleaner end point. Microanalysis confirms a tetrakis ligand formulation, and a negative chloride analysis is obtained with acidified silver nitrate. 1 represents the first structurally characterized uranium dialkylphosphide complex. Uranium(IV) is paramagnetic (5f9, and 31P NMR signals have not been observed for any phosphorus atoms within the complex. Broad resonances are observed in the 'H NMR spectrum, from which detailed structural information cannot be inferred. Th{P(CHsCHzPMes)z}r (2). The reaction of 4 mol equiv of LiPPP or KPPP with ThCL in ethers or hydrocarbons affords red solutions from which red, petroleum ether soluble crystals of 2 may be isolated in good yield. Microanalysis confirms a tetrakis ligand formulation, and a negative chloride test is obtained with acidified silver nitrate. The room-temperature 31P('H} NMR spectrum of 2 contains two broad singlets a t 6 83 ppm ( ~ 1 1 2= ca. 100 Hz)and 6 -34 ppm ( ~ 1 1 2= ca. 400 Hz) which are integrated in a ratio of 1:2, respectively. The former resonance is assigned to the phosphido phosphorus atoms and the latter to the tertiary phosphine atom, on the basis of chemical shift and signal intensity. The broadness of the resonances indicates that 2 is fluxional in solution. This is confirmed by variable-temperature 31P{'H} NMR spectroscopy (Figure 2). Coalescence occurs at about 5 "C; below this temperature, new peaks appear in the regions expected for both coordinated and uncoordinated tertiary phosphine. At the low-temperature limit (-80 "C)
tC0
three resonances are observed of approximately equal signal intensity, which are assigned to coordinated phosphide (6 71 ppm), coordinated tertiary phosphine (6 -8 ppm), and uncoordinated tertiary phosphine (6 -52 ppm). These resonances are still slightly broad ( ~ 1 1 2 = ca. 40 Hz for all three peaks), and no P-P coupling is resolved. The spectra indicate that the fluxional nature of 2 is due to an exchange process involving the rapid exchange of coordinated with uncoordinated tertiary phosphines. The high-temperature (100 "C) spectrum shows a septet attributed to the phosphide (6 89 ppm, ~ 1 1 2= ca. 45 Hz) and a pentet for the tertiary phosphines (6-34 ppm, ~ 1 1 2= ca. 45 Hz, JP-P= 16 Hz). As the sample is warmed through coalescence, the new peak due to the exchanging tertiary phosphines appears and sharpens at a position closer to the low-temperature position of uncoordinated than t o that of coordinated tertiary phosphine. Indeed, the ratio of the distances a t the high-temperature limit position to coordinated versus uncoordinated tertiary phosphine at the lowtemperature limit is approximately 5 3 , respectively. The spectra clearly show that this difference is not due to any linear chemical shift dependency on temperature (due to viscosity or other effects not associated with the fluxional behavior). The position of the tertiary phosphine resonance at the high-temperature limit implies that the tertiary phosphines have, on average, more uncoordinated than coordinated character, which may be attributed to an equilibrium between seven- and eight-coordinate species. Line shape analysis6 allows estimation of AG* (49 f 3 kJ mol-l). That the exchange process is intramolecular is confirmed by addition of the ( 6 )According to the method described by Crabtree in: Crabtree, R. H. The Organometallic Chemistry of the Transition Metals; Wiley: New York, 1988; pp 220-222.
Organometallics, Vol. 14, No. 8,1995 3651
Actinide Complexes with Diphosphinophosphido Ligands I-3 4
observed at all temperatures and are not involved in the fluxional process in 2. At the low-temperature limit, the resonances assigned to pendant PMe2 functions in 2 are almost coincident with those of the tertiary phosphines in free HPPP, as would be expected. In the hafnium dialkylphosphide CpzHf{P(Cy)z}~,~ two broad resonances a t 6 270 and -15.3 ppm, a difference of 285 ppm for two identical phosphido functions bonded to the same metal, were observed a t the low-temperature limit (-126 "C) in the 31P{1H} NMR spectrum. These resonances were assigned to the planar and pyramidal phosphides, respectively, and the variable-temperature behavior was very reasonably interpreted as a rapid u (pyramidal phosphorus) x (planar phosphorus) interconversion a t temperatures above -100 "C, under which conditions a singlet is observed in an averaged position. In 2, the position of the phosphido phosphorus signal is in a region similar to those observed for zirconium PPP complexes and the related hafnium complex above at ambient temperature; we have not observed coalescence of the phosphido resonance in 2 down to -80 "C, where any planar pyramidal interchange would still be expected t o be fast on the NMR time scale. However, this resonance shifts by some 18 ppm t o lower field as the sample warms through coalescence, due t o tertiary phosphine exchange, and is consistent with the phosphide becoming more n bonding in nature. This supposition is reasonable, since the loss of a a-donating tertiary phosphine function from the coordination sphere of the thorium center results in the metal becoming more electron deficient and also allows more freedom for the phosphides to attain the planar geometry required in order t o maximize n bonding. The behavior of 2 is then consistent with a dissociative exchange of tertiary phosphines. This type of fluxionality, i.e. exchange of uncoordinated for coordinated tertiary phosphine, has not been observed in other transition-metal systems with this ligand;3c-e these other complexes are also relatively unreactive. The availability of an incipient coordination site within 2 is of particular interest and no doubt accounts for the unusual reactivity of the complex (vide infra). Structural Comparisons. The X-ray single-crystal structure of 1 (Figure 1) shows that 1 and 2 are iso~tructural~ with eight-coordinate uranium bonded t o four tertiary phosphines and four phosphido phosphorus atoms. Bond lengths, angles, and atomic fractional coordinates are in Tables 1-3, respectively. There are several interesting features t o note, since the complex allows a direct comparison of actinide-tertiary phosphine us actinide-secondary dialkylphosphide bonding. The average U-Pphosphino bond length is considerably longer than the average U-Pphosphido bond length (averages 2.993(2) and 2.778(2) A, respectively), as is to be expectedagIn CpzHf(PEt2)2,X-ray single-crystal diffraction studies showed that the two M-P bond lengths differ by 0.194(1) A and that the phosphorus atom making the closer metal contact is planara8 These observations were interpreted as an increase in the degree of n bonding in one phosphido function relative to the other, and this behavior highlights the potential
-
20°C
10°C
bh
4 -
5°C
ooc
-2OOC
-40°C
4 1 1 _ 1 (
71
-00°C
A-
' o; '
' .do
3'0 '.,!I
P pm
Figure 2. Variable-temperature 31P NMR spectra of T~(P(CH~CH~PM (chemical ~ Z ) ~ }shifts ~ are in 6 (ppm)).
free secondary phosphine, HPPP, to the NMR ample.^ Sharp resonances which are readily assigned t o free HPPP3d(&tertiary -49.6 ppm,dp secondary - 58.6 ppm) are ~~
(7) Variable-temperature 13P{lH}NMR spectra for this experiment are presented in Figure 1 of the supporting information.
-
(8) Baker, R. T.; Whitney, J. F.; Wreford, S. S.Organometallics 1983,
2,1049.
(9)Domaille, P.J.; Foxman, B. M.; McNeese, T. J.;Wreford, S. S. J . Am. Chem. SOC.1980,102,4114.
Edwards et al.
3652 Organometallics, Vol. 14, No. 8, 1995 Table 1. Selected Bond LenPths (A) . . for U(P(CH2CH2PMe2hJ4 2.756(2) 2.761(2) 2.790(2) 2.806(2) 2.976(2) 2.980(2) 2.989(2) 3.019(2) 1.831(7) 1.832(7) 1.834(7) 1.847(8) 1.850(7) 1.36(2) 1.61(2) 1.888(13) 1.902(8) 1.790(8) 1.816(7) 1.84(2) 1.877(14) 1.851(6)
P(5)-C(12) P(6)-C(15) P(6)-C(16) P(6)-C(14) P(7)-C(18) P(7)-C(17) P(7)-C(19) P(8)-C(20) P(8)- C(21) P(9)-C(24B) P(9)-C(24A) P(9)-C(23B) P(9)-C(22) P(9)-C(23A) P(lO)-C(25) P(lO)-C(26) P(10) - a 2 7 P(ll)-C(29) P(ll)-C(28) P(12)-C(32) P(12)-C(31) P(12)-C(30)
1.854(7) 1.797(9) 1.837(9) 1.843(6) 1.818(7) 1.820(7) 1.841(7) 1.838(7) 1.859(6) 1.57(2) 1.81(2) 1.85(2) 1.852(8) 1.879(14) 1.808(7) 1.825(8) 1.830(7) 1.858(6) 1.867(71 1.806(10) 1.817(9) 1.842(6)
Table 2. Selected Bond Angles (deg) for U{P(CH2CH2PMe2)2)4 139.35(6) 117.78(6) 73.08(5) 73.30(6) 122.75(6) 143.81(6) 134.66(5) 78.62(6) 93.07(6) 62.93(5) 85.64(6) 63.68(5) 131.87(6) 80.76(7) 98.00(6) 62.38(5) 86.93(6) 73.80(6) 133.81(5) 162.90(5 83.50(7) 83.86(6) 130.74(5) 63.51(6) 85.29(7) 81.50(6) 164.48(4) 101.58(7) 100.5(4) 99.9(4) 101.4(4) 117.6(3) 121.2(3) 112.9(2) 99.2(4) 125.0(2) 135.7(3) 134.9(11) 87.7(9) 130.2(10) 91.4(6) 94.4(5)
C(9)-P(4)-C(ll) C(9)-P(4)-C(lOB) C(ll)-P(4)-C(lOB) C(9)-P(4)-C(lOA) C(ll)-P(4)-C(lOA) C(9)-P(4)-U( 1) C(11)-P(4)-u( 1) C(lOB)-P(4)-U(l) C(10A)-P(4)-U( 1) C(13)-P(5)-C(12) C(13)-P(5)-U(l) C(l2)-P(5)-U( 1) C(15)-P(6)-C(16) C(15)-P(6)-C(14) C(16)-P(6)-C(14) C(18)-P(7)-C(17) C(18)-P(7)-C(19) C(17)-P(7)-C(19) C(18)-P(7)-U( 1) C(17)-P(7)-U(l) C(19)-P(7)-U(l) C(2O)-P(8)-C(21) C(20)-P(8)-U(l) C(21)-P(8)-U(1) C(24B)-P(9)-C(23B) C(24B)-P(9)-C(22) C(24A)-P(9)-C(22) C(23B)-P(9)-C(22) C(24A)-P(9)-C(23A) C(22)-P(9)-C(23A) C(25)-P(lO)-C(26) C(25)-P(lO)-C(27) C(26)-P(lO)-C(27) C(25)- P(101-U( 1) C(26)-P( 101-U( 1) c(27)-P( 10)-U( 1 C(29)-P(ll)-C(28) C(29)-P(ll)-U(l) C(28)-P(ll)-U(l) C(32)-P(12)-C(31) C(32)-P(12)-C(30) C(31)-P(12)-C(30)
103.7(4) 86.3(9) 112.0(8) 102.7(6) 97.4(6) 118.0(3) 107.9(3) 125.8(7) 123.7(4) 98.6(3) 132.2(2) 120.8(2) 98.4(5) 99.7(3) 98.5(4) 101.1(4) 103.3(4) 99.7(3) 119.9(3) 115.8(3) 114.3(3) 100.7(3) 124.0(2) 131.4(3) 65.7(9) 70.4(6) 101.3(6) 99.8(6) 109.6(7) 99.2(5) 100.0(4) 100.0(3) 103.2(4) 115.5(3) 121.5(3) 113.6(2) 101.2(3) 134.5(2) 124.3(2) 98.6(5) 100.0(4) 101.7(4)
electronic versatility of these ligands. Two of the phosphides in 1 are essentially planar, and two tend toward planarity.1° By comparison with related transition-metal systems, it is reasonable to suggest that the planar phosphido phosphorus atoms are acting as n (10) Sums of angles (in degrees) around the phosphido phosphorus atoms: P(21, 359.9; P(5),351.8; P(8), 356.1; P(111, 360.0.
Table 3. Atomic Coordinates and Equivalent Isotropic Displacement Parametersa (A2x lo3)for UCP(CH2CH2PMe2hh (1) X
U(1) P(1) P(2) P(3) P(4) P(5) P(6) P(7) P(8) P(9) P(10) P(11) P(12) C(1) c(2) c(3) C(4) C(5) C(6) C(7) C(8A) C(8B) C(9) C(1OA) C(1OB) C(11) C(12) C(13) C(14) C(15) C(16) C(17) C(18) C(19) (320) C(21) C(22) C(23A) C(24A) C(23B) C(24B) C(25) C(26) C(27) C(28) C(29) C(30) C(31) C(32)
819(1) 2783(2) 586(2) -2412(5) - 1783(2) 887(2) 3489(2) -713(2) -891(2) - 1766(3) 2965(2) 2836(2) 3271(3) 2177(9) 4478(7) 3257(8) 1942(9) -705(9) -1164(9) -2886(14) -3928(12) -2968(24) -2966(9) -2957(15) -3278(24) -1290(9) -349(9) 2331(7) 2048(7) 4707(9) 2843(11) 138(8) -1203(10) -2341(7) -2041(7) -737(7) -2091(8) -3598(15) -1033(17) -3417(20) -2051(16) 2631(8) 3436(10) 4629(7) 4439(7) 3060(8) 2952(8) 2873(11) 1699(12)
.Y
1957(1) 2720(2) 1807(2) 2303(4) 4503(2) 4407(2) 6527(2) 1469(2) 471(2) - 1808(3) -887(2) 1210(2) 2014(2) 4474(7) 2567(9) 1704(8) 1733(9) 1617(8) 2675(10) 3834(14) 3001(11) 1310(23) 4533(9) 5323(14) 5000(23) 5959(8) 6115(7) 4933(6) 5949(6) 4980(9) 7515(10) -147(7) 2704(8) 1272(8) 192(7) -944(7) -840(8) -1395(16) -3578(15) -2066(22) -2709(14) -2207(6) -1768(8) -1044(7) -382(7) 1970(6) 1194(7) 995(9) 3529(9)
z
2496(1) 3108(1) 3595(1) 4948(2) 2461(1) 1916(1) 983(1) 1611(1) 2790(1) 4330(1) 2741(1) 1754(1) -57(1) 3280(3) 2853(4) 3783(3) 4073(3) 4080(3) 4446(4) 5108(11) 4447(5) 4989(10) 2987(5) 1846(6) 1991(10) 2524(4) 2043(4) 1682(3) 1151(3) 777(4) 313(4) 1348(3) 992(3) 1809(3) 2314(3) 3355(3) 3637(3) 4533(6) 4202(7) 4429(8) 3938(6) 2448(3) 3432(3) 2455(3) 1867(3) 1059(3) 606(3) -506(4) -168(4)
U(ed 34(1) 48(1) 4% 1) 137(2) 48(1) 52(1) 62(1) 46(1) 47(1) 90(1) 4 4 1) 4 31) 69(1) 70(2) 75(2) 65(2) 72(2) 70(2) 78(2) 313(17) 60 60 110(4) 60 60 80(3) 85(3) 48(2) 53(2) 83(3) 94(3) 64(2) 782) 61(2) 55(2) 58(2) 66(2) 60 60 60 60 59(2) 79(3) 58(2) 56(2) 53(2) 53(2) 9U3) 109(4)
U(eq) is defined as one-third of the trace of the orthogonalized
U, tensor.
donors. This view is supported by comparisons with other systems in which planar us pyramidal phosphorus atoms can be directly compared, as in the hafnium example above and in Zr2C13(PPP)3,3cwhere the terminal Zr-Pphosphido bond is 0.237(3) A shorter than the average Zr-Pphosphino bond length. In the only example of a PPP complex where the phosphido phosphorus is PPPz = (MezPCH2pyramidal (i.e. CO(PPP)(PPP~),~~ CH2)2P-P(CHzCHzPMe2)2, where electronic saturation at Co precludes JZ donation from the phosphide t o Co), the CO-Pphosphido bond is longer than the (average) CoPphosphino bond length (by approximately 0.14 A). In the only other structurally characterized actinide phosphide (Cp2Th(P(Cy)z}z)lthe phosphorus atoms are planar. In 1, the degree of distortion from planarity is significant for P5 and P8 and may well be structurally imposed. In this case, dissociation of a tertiary phosphine would presumably help to alleviate this influence and allow the phosphido phosphorus atoms to attain a more
Organometallics, Vol. 14, No. 8, 1995 3653
Actinide Complexes with Diphosphinophosphido Ligands
4
c3
a b Figure 3. Inner coordination sphere and chelate conformations of M{P(CHzCH2PMe2)2}4 complexes (1 and 2b): (a)chelate conformation of 1 (the view is identical for the isostructural2); (b) chelate conformation for 2b. Table 4. Shape Parameters for M{P(CHzCH2PMe2)2}4Complexes ~
polyhedron Dw dodecahedron CzVbicapped trigonal prism Da antiprism U(PPP)46( 1) Th(PPPk, form a (2) Th(PPP14,form b (2b)
~~~
6’ angle (deg) 29.5,29.5,29.5,29.5 0.0, 21.8,48.2,48.2 0.0,0.0,52.4,52.4 22.9,24.8,29.1,43.2 23.8,24.3,29.1,39.6 24.1,27.9,33.4,38.4
9 angle (deg)a 0
14.1 24.5 11.5,20.4 11.1, 28.7 15.3;17.5
structural data source (ref) 14 14 14 this work 4 24
a Since triangulated dodecahedra have two interlocking trapezoidal planes whose corners are defined by pairs of A and B sites, the 4 angles for both these planes have been calculated. PPP = -P(CHzCH2PMe2)2.
rigorously planar geometry, as is implied by the NMR data. This feature may also indicate that the phosphido phosphorus atoms have the ability to achieve differing degrees of n bonding in these complexes. The average uranium-phosphine bond length (2.993(2) A) is significantly shorter than other reported uranium-phosphine bond lengths; e.g., the average U-P distance in U(OPh)4(dmpe)2 is 3.104(6) All (dmpe = 172-bis(dimethylphosphino)ethane). It is not clear whether this difference is due to the relative bulk of the phenoxide hnctions preventing a closer approach of the dmpe ligand in the latter or the chelates containing the relatively short U-Pphosphido bonds shortening the U-Pphosphino bonds in the former. The chelate backbone from the phosphido phosphorus (P(5))to the associated tertiary phosphine (P(4))adopts a different conformation from the other three (Figure 3). P(5) is the phosphide that exhibits the greatest distortion from planarity, and the associated tertiary phosphine (P(4)) has a significantly longer metal-ligand interaction than the other three phosphines. The thorium analogue can be crystallized from light petroleum ether as a mixture of two dimorphs (2and 2b);both have been structurally characterized, and for the sake of the following comparisons, the numbering schemes of 1,2,and 2b are consistent. The coordination geometry of 2 is indistinguishable from that of 1 (Figure 11, as the two compounds are isostructural; a representation of the structures is shown in Scheme 1. Thus, all three compounds conform to NIA4B4 polyhedra, this
behavior having precedent in uranium and thorium complexes of the chelating ditertiary phosphine dmpe. The general structural features of 2 and 2b are similar to those of 1 insofar as the Th-Pphosphido bonds are consistently shorter than the Th-Pphosphino bonds by approximately 0.2 A (respective averages 2.895(5) and 3.075(5)A for 2 and 2.883(2) and 3.095(2) for 2b),and all phosphido phosphorus atoms tend toward planarity. In both thorium compounds, the average Th-Pphosphido bond length is similar to that observed in CpsTh{P(Cy)2}2(2.87(2)A)1 and the average Th-PphoSpfino bond length (3.095(2)A) is slightly shorter than that observed in (PhCH2)4Th(dmpe)(3.155(10) A) (Ph = C6Hs).l2 In the three tetraphosphides 1, 2, and 2b, the coordination geometry around the metal atoms is difficult to identify by inspection of structural diagrams. A more accurate description of the m B 4 eightcoordinate structures may be obtained by analysis of the shape parameters d’ and 4 defined by PoraiKoshits13 and Muetterties14 with the relatively longer bonds to the tertiary phosphines on the A sites and the phosphides in the B sites. These parameters for the three tetraphosphides are collected in Table 4. In all (11)Edwards, P. G.; Andersen, R. A.; Zalkin, A. J.Am. Chem. SOC. 1981,103,7792. (12)Edwards, P. G.; Andersen, R. A.; Zalkin, A. Organometallics 1984,3,293. (13)Porai-Koshits, M. A.; Aslanov, L. A. Zh. Strukt. Khim. 1972, 13,266. (14) Muetterties, E.L.; Guggenberger, L. J. J. Am. Chem. Soc. 1974, 96, 1748.
3654 Organometallics, Vol. 14, No. 8, 1995 Table 5. Comparison of Metal-Ligand Bond Lengths (A) in M(P(CH2CH2PMe2)2}4Complexes (1, lb, and 2) M = U (1) M = Th,form a (1) M = Th,form b (lb)
Edwards et al.
4a). The spectrum consists of a doublet of triplets (6 2.9 ppm), an apparent quartet (6 -16.4 ppm), a doublet (6 -22.6 ppm), two poorly resolved doublets (6 -23.3 and 6 -23.8 ppm), and two doublets at 6 -51 and -52.1 Phosphides ppm. The resonances are integrated as 2:2:2:1:1:2:2, 2.756(2) 2.886(1) 2.828(6) respectively, and therefore numerically account for all 2.790(2) 2.882(5) 2.901(2) phosphorus atoms originally present in 2. The last two 2.806(2) 2.884(5) 2.883(2) resonances are readily assigned to uncoordinated ter2.761(2) 2.843(5) 2.862!1) tiary phosphorus. Since the low-field signal is removed Phosphines ca. 80 ppm upfield from the phosphido signals in 2, it 2.989(2) 3.097(2) 3.070(6) appears that CO insertion has occurred into all of the 3.085(1) 3.019(2) 3.100(5) 3.105(2) 2.976(2) 3.069(6) actinide-phosphide bonds, which would be expected to 3.094(2) 3.062(5) 2.989(2) generate resonances in the region commonly assigned to tertiary phosphines. Two high-field resonances (6 2.9 three compounds, the 6' angles clearly indicate that the and -22.6 ppm) are assigned to the four new tertiary structures most closely conform to triangulated dodecaphosphines generated by the insertion of CO, with the hedra; the 4 angles, however, deviate considerably from former tentatively attributed t o the two coordinated the idealized value (0') for a Dad dodecahedron and (CO) phosphines and the latter to the uncoordinated indicate distortion from dodecahedral geometry toward (CO) phosphines. either bicapped-trigonal-prismatic or square-antiprisThe 31P{1H} NMR spectrum of the 13C-enriched matic geometry. Since two of the 6' angles for an compound 4 (Figure 4b) enables assignment of the idealized square antiprism are zero, the structures are resonances. The resonance at 6 2.9 ppm becomes a probably best described as distorted from dodecahedral complex symmetrical multiplet of at least 14 lines toward bicapped trigonal prismatic, for which the (separation of the outer lines 42 Hz), and the doublet smaller 4 angles for the actinide phosphides agree quite at 6 -22.6 ppm becomes a doublet of doublets (JP-c = closely. By visual inspection, the inner coordination 68 Hz). The spectrum of 4 clearly indicates that CO environments of the molecules appear to most readily has inserted into two metal-phosphide bonds, since two fit a distorted trigonal prism capped by the phosphido different chemical shifts arise due to phosphorus atoms atoms P(2) and P(5) with P(l),P(101, and P(11) forming directly bonded to carbon (of CO). In order to account one face and P(41, P(71, and P(8) forming the other of for the number of resonances, it also appears that the the two triangular faces of the prism. These planes are phosphorus atoms bonded t o the inserted CO are at rotated with respect to each other away from idealized least pairwise equivalent; this in turn implies that two geometry and have a dihedral angle of 8.5". The CO molecules have inserted. Since two PPP ligands distortion is almost certainly caused by the constraints appear to be bound (via the central phosphorus) to each within the chelate rings preventing P(1) and P(4) from carbon atom from CO, the difference in chemical shifts obtaining idealized positions. 2 and 2b can be considsuggests that one phosphorus is coordinated t o thorium ered as conformational isomers, since in 2b one of the and one is not, the latter being assigned to the higher chelate rings (the chelate from P(4) to P(5))is puckered field resonance (6 -22.6 ppm) since it is in a region in an opposite direction from that in 2. This is the major normally expected for similar higher alkyl tertiary structural difference between the dimorphs and is more phosphines (e.g. in HP(CHzCHzPEtz)z, G[P(tertiary)l clearly shown in Figure 3a. In 1 and 2 the chelates -21.1 ~ p m ) .Unfortunately, ~ ~ there are no known described by P(10)to P(11)and P(4)to P(5) lie syn across similar compounds for comparison. The resonances at the thorium atom, whereas in 2b they lie anti. 6 -16.4, -23.3, and -23.8 ppm are assigned to the The metal-ligand bond lengths (Table 5) are consiscoordinated PMez tertiary phosphines. The room-temtently shorter in the uranium compound than in the perature spectrum also differs from that of 2 in that the thorium compounds, indicating that the effective ionic resonances are sharp. When the temperature is lowradius of uranium is 0.08 A smaller than that of thorium ered, the spectrum does not vary; however, at higher in these ~omp1exes.l~ temperature a new broad signal appears at 6 -11 ppm, Th[CO{P(CH2CH2PMe2)2}212 (3) and Th[lSCOtogether with a universal loss of coupling information. {P(CH2CH2PMe2)2}212 (4). In the presence of COz, This is attributed to coordinated tertiary phosphine and NOz, CS2, Ha, and CH3CN, 2 reacts to give intractable suggests that some exchange process(es1 between cooror otherwise unidentified products. However, the indinated and uncoordinated tertiary phosphines are teraction of 2 with CO in hydrocarbons generates deep occurring at elevated temperature. red solutions from which 3 can be isolated from light The lH NMR spectrum of 3 consists of five doublets petroleum ether solutions in good yield. Microanalysis between 6 0.9 and 1.4 ppm with relative intensities 1:l: confirms the stoichiometryTh[CO{P(CHZCHZPM~Z)Z}ZIZ. 1:l:l. In addition there is a multiplet (of relative Upon reaction with CO, the resonances attributed to intensity 3) assigned to coincident methyl resonances the phosphido phosphorus atoms in the 31P{1H}NMR centered at 6 0.98 ppm and broad multiplets attributed spectrum of 2 disappear. New resonances at higher to methylene backbone protons. Since the 31P{1H}NMR field values accompany the formation of 3, which only spectra indicate the tertiary PMez functions are pairshows signals in regions commonly attributed t o coorwise chemically equivalent betwedn the two ligand dinated and uncoordinated tertiary phosphines (Figure systems, this must be true for the methyl protons. In view of this, the multiplicity of the methyl resonances (15)The effective crystal radius of eight coordinate thorium is 1.19 in the proton NMR implies that they are diastereotopic, A, compared with 1.14 A for uranium: Shannon, R. D. Acta Crystallogr., Sect. A 1976, 32, 751. as is the case in the solid-state structure.
Actinide Complexes with Diphosphinophosphido Ligands
1
1
0
-10
Organometallics, Vol. 14, No. 8, 1995 3655
I
I -20
- 30
- 40
-50
Figure 4. 31PNMR spectra of T~(CO[P(CHZCHZPM~Z)ZIZ}Z, (3)(chemical shifts in 6 (ppm)): (a) natural-abundance l3C; (b)isotopically enriched 13C with the low-field resonance expanded (inset). The resonances due to noncoordinated tertiary phosphine functions appear as in (a).
v 72
70
I 40
I 30
I 20
I 10
Figure 5. 13C NMR spectrum of T~(CO[P(C~ZCHZPM~Z)ZIZ}Z, (3)(chemical shifts in 6 (ppm)). The lH NMR spectrum of 4 is similar to that of 3 except that further coupling information (Jc-H)is observed in the resonances due to the phosphine methyl protons. The l3C{lH) NMR spectrum of 3 is complex in the aliphatic region, more so than for 2. Resonances attributed to tertiary phosphine methyl carbons and to methylene backbone carbons are identified. A new resonance appears as a doublet of overlapping doublets a t 6 72 ppm, where the separation of the outer lines is 110 Hz with each doublet having a different coupling constant (4Jc-p is 68 and 42 Hz). It is only this resonance !hat is enhanced in the spectrum of the 13Cenriched analogue 4, confirming its origin as the carbon from CO. The larger coupling constant is confirmed by and can be assigned to the noncoordinated phosphorus by comparison with the 31P{1H}NMR spectrum, indicating that the C-P bond to the coordinated phosphorus is relatively weaker. This signal is in a position more commonly associated with secondary alcohol than carbonyl functions, cf. 6 3.3 ppm in the structurally characterized phosphidoacyl species (v5-Cp*)HfC1z(v2COPtBu2).16 The IR spectrum is consistent with a C-0
single bond (vc-0 1065 cm-l). This assignment is confirmed by the expected isotopic shift in 4 (v13c-o 1035 cm-l). The X-ray crystal structure of 35 reveals that the solid-state and solution structures are consistent; this is represented in Scheme 1. The complex contains tencoordinate thorium bonded to two dianionic (formally for Th(IV))diphospha secondary alkoxy ligands generated as a result of CO insertion into M-PR2 bonds. Only two CO molecules have inserted, each into two metalphosphide bonds with reduction of the bond order in CO from 3 to 1. Each PzCO unit in the newly generated { (MezPCHzCH2)2P}zC02- ligand is y3-bonded to the thorium atom (the hapticity assigned to the molecule refers to the linkages local t o the inserted CO group) with one of the phosphorus atoms coordinated to thorium; for each phosphorus atom, one pendant dimethylphosphino donor remains coordinated to thorium and the other is uncoordinated. The bond lengths in each ThPZCO are consistent with Th-0, Th-C, and C-0 single bonds. 3 represents only the second structurally characterized example of an insertion reaction into a M-P bond16J7 (the first for an f-block metal), a new
(16)Roddick, D. M.; Santarsiero, B. D.; Bercaw, J. E. J . Am. Chem. SOC.1986,107, 4670.
(17)Smith, W. H.; Taylor, N. J.; Carty, A. J.J . Chem. SOC.,Chem. Commun. 1976, 896.
3656 Organometallics, Vol. 14, No. 8,1995
Edwards et al.
Scheme 2. Possible Intermediates and Canonical Forms Involved in CO Insertion
The IR spectrum of 5 has a strong absorption assignable to YO-H (3208 cm-l) and an absence of bands in the region associated with carbonyl YC-0 absorptions. The remainder of the spectrum is very similar to that of HPPP except for the absence of YP-H. The mass spectrum of 5 (CI) does not show a molecular ion; the highest mass peak observed is at 238 amu, which is A B C explained by the cleavage of HP(CH&H2PMe2)2 (mass mode of insertion for CO, and the first instance of a v3 210 amu) from 5 (mass 448 amu), generating the insertion product. aldehyde (Me2PCH2CH2)2PCHOof mass 238 amu. The reaction can be thought of as being driven by the Reactions of Th{P(CH2CH2PMe2)2}4 with Phecoordination of oxygen to oxophilic thorium following nols and Alkenes. The tetraphosphide 2 reacts with dissociation of a tertiary phosphine, thereby generating a number of reagents with acidic protons. From these an incipient coordination site in solution. The resultant reactions, no well-characterized materials were isolated polarizing of the C-0 bond renders it susceptible to pure in the solid state, although solution spectroscopy intramolecular nucleophilic attack by coordinated phosgives valuable insight into the reactivity of 2. phide. Substantial contribution from the canonical form The reaction with 2 mol equiv of phenol (per 2) in B is implicated (Scheme 2). It is noteworthy that the hydrocarbons results in new resonances assigned to contribution from form C is not sufficient to prevent this coordinated PPP in the 31P{1H} NMR. The roomprocess. temperature 31P{1H} NMR spectrum of the reaction Surprisingly, 1 does not appear to react with CO even product appears as a binomial five-line multiplet (6 34.5 under more forcing conditions (70 "C, 7 atm). This ppm) and a symmetrical triplet (6 -10.96 ppm). This relative lack of reactivity is under investigation. is consistent with an &M2 spin system, suggesting that HC(OH){P(CH2CH2PMe2)2}2(5). The addition of the product is a monomeric bis(phenoxide)complex with water to 3 generates a white precipitate (Th02) and the two tridentate PPP ligands per thorium. The stoichigrease 5. In the 31P{1H}NMR spectrum of 5, a triplet ometry of the reaction was confirmed by titration of a of equally intense lines at 6 -50.7 ppm and a symsolution of 2 with a solution of phenol. The elimination metrical five-line multiplet at 6 -17.1 ppm are observed of HPPP continues until 2 mol equiv of phenol (per Th) in a ratio of 2:1, respectively. The former is assigned is added. The further addition of phenol produces no to the terminal tertiary phosphines on the basis of more HPPP relative to the product (PhO)2Th(PPP)2. chemical shift and the latter to the internal phosphorus Compound 2 also reacts with alkenes in hydrocarbons atoms. The spectrum can be explained in terms of an to generate colorless complexes that contain new resoAA'BB'MM spin system, indicating pairwise magnetinances assigned to coordinated PPP in the 31P{1H} cally inequivalent dimethylphosphinogroups A and B, NMR. The 31P{1H} NMR spectrum of the product where the only significant coupling constants are 2 J ~ , isolated from the reaction of ethene with 2 contains two 3 J ~3JBM, , 3 J ~and~ 3JB34'. , The internal phosphorus broad resonances at 6 31 ppm ( ~ 1 1 2= 274 Hz) and 6 4 atoms (MM) are then each coupled to one A and one B ppm ( ~ 1 1 2= 630 Hz) of equal intensity. Signals atphosphorus atom and to each other, giving rise to a fivetributed to HPPP are also observed (6 -52 and -60 line pattern. The terminal phosphines are inequivalent, ppm). Similar spectra are observed from the products since rotation of the P-C bonds to the central prochiral of the reactions of 2 with propene or 2-methylbut-2-ene. carbon cannot generate equivalent positions for the No reaction occurs when 2,3-dimethylbut-a-ene is emtertiary phosphines on each side of the molecule. The ployed under similar conditions. This indicates that a spectrum can be satisfactorily simulated on this basis.18 vinylic proton a to the carbon-carbon double bond is This suggests that the apparent quartet at 6 -16.4 ppm required for the reaction to proceed. Monitoring the in the 31P{1H}NMR spectrum of 4 may be assigned to reactions by 31P{lH} NMR spectroscopy indicates that the CO-bonded phosphorus atom that is not coordinated the reaction stoichiometry of alkene:2 was 2:1, since the to thorium, the chemical shift difference being 0.7 ppm generation of HPPP, the other reaction product, was at between coordinated and protonated ligand. a maximum when 2 mol equiv of alkene was added. In the lH NMR spectrum the methyl protons are centered at 6 0.88 ppm as two doublets coupled to the Experimental Section pairwise inequivalent phosphorus atoms. The pattern is similar to that observed for the uncoordinated phosAll manipulations were performed using a Vacuum Atmophorus methyl protons in 3. The methylene backbone spheres HF-43-2 or Halco Engineering 140 FF glovebox, or protons are located at 6 1.6 ppm as a broad multiplet. using standard Schlenk techniques under purified nitrogen. Doublets integrated as one proton appear a t 6 4.28 and Unless otherwise stated, all solvents were refluxed under nitrogen over sodiumhenzophenone and were distilled im2.16 ppm and are assigned to the unique carbon CH and mediately prior to use. Toluene was refluxed under nitrogen OH protons, respectively. The latter resonance disapover sodium and was distilled immediately prior to use. Light pears after exchange with D20, and the former collapses petroleum ether had bp 40-60 "C. Perdeuterio solvents were to a singlet (Figure 6). refluxed over sodium (8 h) and distilled therefrom under In the 13C{lH} NMR spectrum, the unique carbon is nitrogen. ThC14 was dried by refluxing with thionyl chloride located at 6 72 ppm as a binomial triplet coupled to two (5 d), washed repeatedly with dichloromethane (freshly disequivalent phosphines (4Jp-c = 29 Hz). tilled under nitrogen from CaHd until the filtrate was color(18)NMR simulation using Bruker "PANIC" software generates the following parameters: &A) -51.0 ppm, &B) -50.9 ppm, b(M) -17.0 ppm, 2 J ~ M = 5 Hz,3 J =~3 J =~ ~ = 3 J ~ m=. 12 Hz,and all '3J = 0. 3
J
~
1
~
less, and dried in vacuo (0.05 mmHg, 150 "C, 8 h). UCL was prepared by following a modified literature route;lgHPPP and LiPPP were prepared as previously described.3d KPPP was prepared by refluxing HPPP with excess K in light petroleum
Actinide Complexes with Diphosphinophosphido Ligands
_ b k
Organometallics, Vol. 14, No. 8,1995 3657
'
'
H
+ 1 4
+ I 3
n.
1 1
A I
I
2
1
Figure 6. 'H NMR spectra of HC(OH)(P(CH2CH2PMe2hh(5) (chemical shifts in 6 (ppm)): (a)before addition of D20 (the peaks marked + are t h e P-H resonances of the HPPP impurity); (b) after addition of DzO. ether, followed by filtration, extraction into boiling toluene, and crystallization. Microanalyses were performed by CHN Analysis Ltd., Leicester, U.K. NMR data are quoted in ppm, and spectra were recorded on a JEOL FX9OQ operating at 36.23 MHz (variable-temperature 31Pand 'H in CjDs, 13C{lH} in C6D6) or a Bruker W M 3 6 0 operating a t 145 MHz. 31PNMR spectra were referenced externally to 85% H3P04 (6 0 ppm); I3C and 'H NMR spectra were referenced to solvent carbons (C7D8, d 137.5 ppm) or residual protons (C7D8, d 7.19 ppm). Melting points were recorded in sealed glass capillaries and are uncorrected. U{P(CH2CH2PMe2)2}4 (1). To a stirred solution of UC14 in THF (0.14M, 3 cm3) a t -80 "C was added KPPP in 4:l toluene/THF (0.1687M, 10 cm3). The mixture was stirred for 8 h, during which time the color changed from green t o black. The volatile materials were removed in uacuo. The resultant black solid was washed with cold (-80 "C) light petroleum ether (2 x 10 cm3) and extracted with light petroleum ether (2 x 50 cm3). The black supernatant was evaporated to ca. 20 cm3 and cooled (-20 "C) for 4 h. 1 crystallizes as small black prisms in good yield (0.33 g, 72%). Mp: 132-136 "C. Anal. Found: C, 34.7;H, 7.24. Calcd for UP&&s0: C, 35.8; H, 7.50. IR (Nujol, cm-'): 1305 (m), 1145 (s), 1121 (w), 1080 (m), 969 (m), 937 (w), 921 (m), 890 (w), 805 (m), 771 (m), 333 (w). 'H NMR (BH, 89.5 MHz, CjDs, 20 "C): -24.21 (8H,S, PCHz), -25.87 (8H, s, PCHz), -27.54 (24H,br v112 = 45 Hz, PCH3). Th{P(CH&H2PMe&}4 (2). ThCL (0.54g, 1.44mmol) was suspended with stirring in diethyl ether (100cm3) and cooled (19) Brown, D.C.Halides ofthe Lanthanides and Actinides; Wiley: London, 1968; p 136, and refs 112 and 113 therein.
until frozen. LiP(CHZCH2PMez)z (1.25g, 5.78 mmol) in THF (10 cm3) was then added. Initially a yellow color developed, which became red a t -20 "C. The suspension was warmed to room temperature and then stirred (12h). The solvents were removed in vacuo, and the red residue was washed with cold (-80 "C) light petroleum ether (2 x 10 cm3). Extraction with light petroleum ether (3 x 30 cm3) and concentration of the filtrate to ca. 20 cm3 followed by cooling (-20 "C, 1 h) afforded red crystals of 2 (0.66 g, 43%). Mp: 132-136 "C. Anal. H ~35.9; O : H, Found: C, 34.7;H, 7.90. Calcd for T ~ P I z C ~ ~ C, 7.50. IR (Nujol, cm-'1: 2023 (w), 1290 (m), 1145 (s), 1115 (w), 1075 (m),960 (m), 930 (m),910 (m),885 (w),805 (m), 765 (m), 330 (w). 31P{1H}NMR (dp, 36.23 MHz, C7Ds): 83 (br, Y I / Z = 100 Hz), -34 (br, v1/2 = 400 Hz). 'H NMR ( d ~ 89.5 , MHz, C7D8): 2.6 (2H,br, v1/2 = 30 Hz), 1.8 (2H, br, V I / Z = 30 Hz), 1.3 (6H,SI. Th[CO{P(CH&H2PMe2)2)212 (3). A flask containing a solution of 2 (0.25 g, 0.23 mmol) in toluene (30 cm3) was evacuated, filled with CO (to 5 psi above ambient pressure), and sealed. The solution was stirred at room temperature (8 h), during which time the color turned from red to purple. After removal of the volatile materials in uacuo, the residue was washed with cold (-80 "C) light petroleum ether (2 x 10 cm3) and extracted with light petroleum ether (3 x 30 cm3). The purple supernatant was evaporated to ca. 15 cm3 and cooled (-65 "C) for 4 h. 3 crystallizes as red prisms in good yield (0.19g, 73%). Mp: 144-146 "C. Anal. Found: C, 35.9;H, 6.80. Calcd for ThPlzC38H800~:C, 36.3;H, 7.17. IR (Nujol, cm-l): 1305 (m), 1291 (w), 1280 (w), 1265 (m), 1210 (w), 1169 (m), 1155 (m), 1088 (91, 1063 (SI, 969 (m), 937 (s), 921 (m), 890 (w), 844 (w),805 (m), 771 (w), 670 (w),523 (m). 31P{1H}NMR
3658 Organometallics, Vol. 14, No. 8, 1995
Edwards et al.
1.406 Mg m-3, F(OO0) = 1088, p(Mo Ka) = 3.597 mm-l, black (dp, 145 MHz, C7D8): 2.9 (2P, dt, J p - p = 35 and 14 Hz, air-sensitive prisms, crystal dimensions 0.20 x 0.15 x 0.08 = 35 Hz), -22.6 (2P, d, JP-P respectively), -16.4 (2P, q, JP-P mm3. = 15 Hz), -23.3 (lP, d, J p - p = 6 Hz), -23.8 (lP, d, J p - p = 6 Hz), -51.1 (2P, d, J p - p = 15 Hz), -52 (2P, d, J p - p = 15 Hz). Data Collection and Processing.20Data collection was 'H NMR ( b ~360 , MHz, C6D6): 1.6 (16H, br m, v1/2 = 72 Hz), by a Delft Instruments FAST TV area detector diffractometer 1.4 (3H, d, 2 J p - ~= 3 Hz), 1.13 (3H, d, 2 J p - ~= 3 Hz), 1.08 (3H, positioned a t the window of a rotating anode generator using = 3 Hz), 1.03 (3H, d, *JP-H = 3 Hz), 0.98 (3H, d, 2 J ~ - ~ Mo Ka radiation (,= d, 'JP-H I0.710 69 A). A total of 17 709 reflections = 3 Hz), 0.94 (3H, d, 2 J p - ~= 3 Hz). were measured (2.22 5 I9 5 29.74'; index ranges -14 5 h 5 Th[l3CO{P(CH2CH2PMe2)2}2h(4). This procedure was 14; -11 c k c 13; -33 5 1 5 251, with two rejected for lying identical with that for 3, except for the use of enriched 13C0 behind the backstop, giving rise to 11664 unique reflections (in place of natural-abundance CO). For 0.35 g (0.33 mmol) (merging R = 0.0378). of 2 in toluene (20 cm3), 30 cm3 (1.3 mmol) of 13C0 was used. Structure Analysis and Refinement. The structure was 4 was crystallized as above. IR (Nujol, cm-'1: 1305 (m, br), solved by direct methods (SHELX-S)21and refined by full1292 (m), 1278 (m), 1263 (m), 1209 (w), 1170 (m), 1155 (m), matrix least squares (SHEIXL-93)22using all unique Fo2data 1081 (s), 1035 (s), 967 (m), 937 (s), 921 (m), 892 (w), 846 (w), corrected for Lorentz and polarization factors. The non807 (m), 771 (SI, 669 (w), 523 (m). hydrogen atoms were refined anisotropically. The hydrogen HC(OH){P(CH2CHSMe2)2}z (5). Water (5 cm3)was added atoms were included in calculated positions with the Ui,, to a stirred solution of 3 (0.15 g, 0.14 mmol) in light petroleum values set a t 1.2 times the U,, values of the parent carbons. ether (15 cm3), causing a pale yellow solution (organic phase) An empirical absorption correction was applied using DIto develop. The organic phase was separated and dried FABS23(minimum and maximum absorption correction factors (MgS04,2 h), following which the light petroleum ether was were 0.869 and 1.284, respectively). The weighting scheme removed in uacuo to leave crude 5. The deuterated analogue ) ~ , gave satisfactory agreement used was w = ~ / u ~ ( F ,which HC(OD){P(CH2CH2PMe2)2}2 was prepared by H/Dexchange analyses. Final R1 = z(M)/z(Fo) and wR2 = X { W ( A ( F ) ~ ) } / by adding excess D 2 0 to a sample of 5 in an NMR tube. ~ { W ( F , ~ )values ~ } ~ 'are ~ 0.0563 and 0.1191, respectively, for IR (liquid film, cm-l): 3208 (br), 2950 (s), 2920 (m), 2886 409 parameters and all 11664 data (em,,,emax = -0.99, 1.39 (s), 2801 (w), 1410 (s), 1280 (m), 1263 (m), 1248 (s), 1150 (s, e A-3, (Mu)max = -0.09). The corresponding R indices for 6836 br), 1081 (s, br), 1010 (s, br), 926 (s), 877 (w), 830 (w), 786 (SI, data with I > 2dZ) are 0.0370 and 0.0930, respectively. 694 (s). 31P{1H}NMR (dp, 145 MHz, C&3): -17.1 (2P, m), Sources of scattering factors are given in ref 23. All calcula-50.7 (4P, t). 'H NMR (BH, 360 MHz, CsD6): 4.28 ( l H , d, JP-H tions were performed on a 486DX2/66 personal computer. In = 7 Hz), 2.16 ( l H , d, J p - H = 7 Hz), 1.60 (16H, br m, ~ 1 1 2= 94 the early difference maps and in subsequent refinement it Hz), 0.88 (24H, dd, 2 J p - ~= 2.4 Hz). 13C{lH} NMR (dc, 90 became apparent that the terminal methyl groups (C(81,C(lO), MHz, C&): 72 ( l C , t, l J p - c = 29 Hz). Other peaks are C(23), C(24)) exhibited positional disorder and could be observed in the aliphatic region. satisfactorily modeled assuming two alternative atomic sites Reactions of 2 with Phenols. To a stirred solution of 2 for these atoms with the following fractional occupancies: (O.lOg, 0.09 mmol) in toluene (20 cm3)at -80 "C was added a C(8A), 0.67; C(88), 0.33: C(lOA), 0.62; C(lOB), 0.38; C(23A), solution of phenol in toluene (0.01 M, 18.7 cm3). The mixture 0.57; C(23B), 0.43; C(24A), 0.48; C(24B), 0.52. was warmed to room temperature and stirred for 8 h. Removal of the volatile materials in uucuo and subsequent extraction Acknowledgment. We thank the SERC for stuof the residue with light petroleum ether (2 x 10 cm3)affords dentships (J.S.P. and P.W.R.) and access to the mass orange solutions from which orange crystals may be obtained. spectrometry unit at University College Swansea. We Reactions with substituted phenols were performed in a are indebted to H. F. Lieberman and M. B. Hursthouse similar manner. 31P{1H}NMR (dp, 36.23 MHz, CsD6): 34.5 (lP, m), -10.96 (2P, t). of this Department for help in the structural determiReactions of 2 with Alkenes. A flask containing a nation and S. J. Coles for help with calculating the solution of 2 (0.10 g, 0.09 mmol) in toluene (20 cm3) was shape parameters. We also thank A. Karaulov for MAE', evacuated, filled with ethene (to 10 psi above ambient presan interactive molecular graphics program to aid in the sure), and sealed. The solution was stirred a t room tempercrystal structure analysis of large molecules a t atomic ature for 8 h. After removal of the volatile materials in uacuo, resolution (4000 atoms PC386-Pentium version 2.51, the residue was extracted into light petroleum ether (2 x 15 Jan 1994, Department of Chemistry, University of cm3). Evaporation of the filtrate t o ea. 5 cm3 affords a purple Wales, Cardiff CF1 3TB, U.K.). material. Reactions with other alkenes were performed with the alkene being added as a 0.01 M solution to the reaction Supporting InformationAvailable: Tables giving anisomixture uia syringe. 31P{1H}NMR (dp, 36.23 MHz, C6D6): 31 tropic displacement parameters for the non-hydrogen atoms (br, v1/2 = 274 Hz), 4 (br, ~ 1 1 2= 630 Hz). and hydrogen atom parameters for 1 and a figure giving X-ray Crystallography. Crystals of 1 suitable for X-ray variable-temperature 31PNMR spectra for 2 (4 pages). Orderwork were grown from petroleum ether and sealed under ing information is given on any current masthead page. purified nitrogen in Lindemann capillaries. Crystal Data: C & ~ O P ~ ~MU, , = 1074.63, triclinic, a = OM940719D 10.455(5)A, b = 10.521(7)A, c = 25.147(7) A, a = 81.43(3)", /3 = 89.02(2)", y = 68.22(2)", V = 2538(2) A3 (by least-squares (21) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467. refinement of diffractometer angles for 250 reflestions within (22) Sheldrick, G. M. University of Gottingen, Gottingen, Germany, I9 = 2.22-29.74", ,I= 0.710 69 81, space group P1, Z = 2, D,= 1993. (20) Drake, S. R.; Hursthouse, M. B.; Malik, K. M. A,; Miller, S. A. S. Inorg. Chem. 1993, 32, 4653.
(23) Walker, N. P. C.; Stuart, D. Acta Crystallogr., Sect. A 1983, 39, 158. (24) Edwards, P. G.; et al. Acta Crystallogr., Sect. C.1995, in press.
