Masked Iminophosphide Anion: Synthesis and Versatile Reactivity

Feb 1, 1995 - Armelle Mahieu, Alain Igau, Joeel Jaud, Jean-Pierre Majoral. Organometallics , 1995, 14 (2), pp 944–952. DOI: 10.1021/om00002a047...
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Organometallics 1996, 14, 944-952

944

Masked Iminophosphide Anion: Synthesis and Versatile Reactivity Armelle Mahieu, Main Igau, Joel Jaud, and Jean-Pierre Majoral" Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, 31 077 Toulouse Cedex, France Received September 14, 1994@ The unprecedented iminozirconiophosphorane 3, MeaP(ZrCp2Cl)=N-h (Ar = 2,4,6-tB u ~ C ~ Ha ~masked ), iminophosphide, has been prepared by reacting chloroiminophosphane 2, C1-P=N-Ar, with CpzZrMe2. Insertion reactions into the zirconium-phosphorus bond take place when 3 is reacted with nitriles, paraformaldehyde, or carbon disulfide, giving rise to iminophosphoranes. Formal insertion into the nitrogen-zirconium bond occurs when 3 is treated with isocyanides RNC (R = Me3SiCH2, cyclohexyl), affording phosphanes. A single-crystal X-ray structure of one of them has been determined. Addition of pyridineHCl, methyl iodide, N-bromosuccinimide, or various chlorophosphanes to 3 leads to iminophosphoranes via exchange reactions taking place directly on the phosphorus center of 3. Addition of the Eschenmoser salt [H2C=NMe2]C1 to 3 affords a mixture of iminophosphorane and phosphonium salt. 3 reacts with triflic acid or methyl trifluoromethanesulfonate, giving exclusively phosphonium salts. Reactions involving the thermodynamically occur when 3 is stable form of 3,i.e. the phosphane 5, Me2P-N(ZrCp2C1)(2,4,6-t-Bu3C6H2), treated with the chloroiminophosphane 2 with formation of a phosphanyliminophosphane. Treatment of 3 with NiCl2 or PdCL gives rise to the complexes 28a (M = Ni) and 28b (M = Scheme 1

Introduction Among all the possible anionic phosphorus species which can be envisaged,l only a few of them are well described: phosphido derivatives RZP-,~ phosphoranides R4P-,3 and hexavalent phosphorus anions R6P- 4a and R4P-=N-.4b Compounds of general formula [PX& have also been characterized. The metaphosphate ion [PO& has given rise to numerous studies; this species is thought to be an intermediate in the hydrolysis of phosphoric ester^.^ Lastly, the X-ray structure of [PS& and that of the tris(methy1ene)phosphate l7

have been reported. In contrast, a few reports deal with @Abstractpublished in Advance ACS Abstracts, January 1, 1995. (1)Wolf, R. Pure Appl. Chem. 1980,52, 1141. (2)See for example: Gallagher, M. In CRC Handbook of Phosphoncs31 Nuclear Magnetic Resonance Data; Tebby, J . C., Ed.; CRC Press: Boston, MA, 1990;Chapter 2a, pp 45-49. (3)See for example: Riess, J. G.; Schmidpeter, A. In CRC Handbook of Phosphorus-31 Nuclear Magnetic Resonance Data; Tebby, J. C., Ed.; CRC Press: Boston, MA, 1990;Chapter 17,pp 501-505. (4)(a)See for example: Lamande, L.; Koenig, M. In CRC Handbook of Phosphorus-31 Nuclear Magnetic Resonance Data; Tebby, J . C., Ed.; CRC Press: Boston, MA, 1990;Chapter 19,pp 553-567. (b)Baceiredo, A.;Bertrand, G.; Majoral, J. P.; Dillon, K. B. J. Chem. SOC.,Chem. Commun. 1985, 562. (5) Westheimer. F. H. Science 1987.235. 1173. (6) Roesky, H. W.; Ahlrichs, R.; Brode, S . Angew. Chem., Znt. Ed. Engl. 1986,25, 82. (7)Appel, R.; Gaitzsch, E.; Knoch, F. Angew. Chem., Int. Ed. Engl. 1985, 24, 589.

L

J

Me

I

R2N-P =N -R

I

H R = SiMq

the iminophosphide anion >P=N-. Transient generation of such a species is postulated during the treatment of the phosphaimine (Me3Si)zN-P=N-SiMe3 with MeLi8 (Scheme 1). A single-crystal X-ray crystallographic study of [Li(PhN-PPh2)(OEt2)12 shows that the lithium cations are ligated by both of the heteroatoms of the PhN-PPh2- anion. However, the P-N distance (1.672 A) is in the range of the P-N single-bond length^,^ and ab initio calculations carried out on the parent phosphinoamidehminophosphide anion HzPNH-, suggest that this system is best described as the phosphinoamide anion HzPNH- with the negative charge mainly located on nitrogen.1° Therefore, to the best of our knowledge, no stable linear iminophosphide anion >P=N-, as well as no useful precursor of such a species, has been reported.ll Indeed the high electronegativity of nitrogen appears (8) Cowley, A. H.; Kemp, R. A. J. Chem. SOC.,Chem. Commun. 1982, 319.Cowley, A. H.;Kemp, R. A. Inorg. Chem. 1983,22, 547. (9)Ashby, M. T.; Li, Z. Inorg. Chem. 1992,31, 1321. (10)Trinquier, G.; kshby, M. T. Inorg. Chem. 1994, 33, 1306. (11)Versatile reactivity of the (1,3-diaza-2-phosphaallyl)lithium complex [RNPN(aryl)lLi (R = t-Bu, aryl = 2,4,6-t-BusCsHz) toward diphenylchlorophosphane has been demonstrated: P and N addition products were isolated. See: Detsh, R.; Niecke, E.; Nieger, M.; Schoeller, W. W. Chem. Ber. 1992, 125, 1119.

0276-733319512314-0944$09.O0/0 0 1995 American Chemical Society

Masked IminophosphideAnion

Organometallics, Vol. 14,No. 2, 1995 945 Scheme 2. Synthesis and Thermal Stability of 3

CI-P=N-Ar

+

ChZr, Me

-

-40o c

Me Me-P=N-Ar I

I

ZrChMe 4

2

ZrCpZCl 3 p " C

Me,

/Ar

Me,p-N'H 6

to be the dominant factor which hinders the formation of such anionic species. We anticipated that P-metalated iminophosphoranes R2P(M)=N-R (M = metal) might act as precursors of iminophosphides. However, none of these derivatives have yet been described. It can only be mentioned that the X-ray structures of diphosphazene complexes M[(CF3)2P=N=PPh31n(n = 1, M = Fe(C0)4;12n = 1, M = O S ~ ( C O )n~=~ 2, ; ~M~ = PdCl2, Fe(C0)314) show that the two P-N lengths are very similar and therefore that the unsymmetrical PNP fragment is highly delocalized, presumably owing to the effect of the strongly electron-withdrawing CF3 moiety. In contrast, a number of acyclic and cyclic N-metalated iminophosphoranes have been prepared, most of this work being carried out by Roesky et al.,15 Elsevier et a1.,16 and Cavell et al.17 In a preliminary communicationla we reported the synthesis of the iminozirconiophosphorane3 MezP(ZrCp2Cl)=N-2,4,6-t-B~3CsH2,the first P-metalated iminophosphorane, and a few reactions with this compound. Herein we report full details of the synthesis and the reactivity of this derivative. Four main types of reactions will be described: (i) insertion reactions into the P-Zr bond, (ii) formal insertion into the N-Zr bond, (iii)reactions a t phosphorus, (iv) reactions at nitrogen. These examples will demonstrate the versatile behavior of this first representative of a new class of compounds, reacting either as the masked iminophosphide [MezP=N(2,4,6-t-Bu3CsH2)1[ZrCp2Cll or as the (zirconioaminolphosphane Me2P-N(ZrCp2C1)-2,4,6-t-Bu&&I2. Results and Discussion

Addition of CpzZrMez t o a pentane solution of the chloroiminophosphane 2 a t -40 "C leads to the white (12)(a) Ang, H. G.; Cai, Y. M.; Kwik, W. L.; Rheingold, A. L. J . Chem. Soc., Chem. Commun. 1990, 1580. (b) Ang, H. G.; Cai, Y. M.; Kwik, W. L.; Morrison, E. C.;Tocher, D. A. J . Organomet. Chem. 1991, 403, 383. (13) Ang, H. G.;Cai, Y. M.; Kwik, W. L.; Leong, W. K. Polyhedron 1991, 10, 881. (14) Ang, H. G.; Cai, Y. M.; Koh, L. L.; Kwik, W. L. J. Chem. SOC., Chem. Commun. 1991,850. (15) See for example: Roesky, H. W. In The Chemistry oflnorganic Ring Systems; Steudel, R., Ed.; Studies in Inorganic Chemistry 14; Elsevier Science Publishers: New York, 1992; p 255. Witt, M.; Roesky, H. W. Chem. Reu. 1994,94,1163. Roesky, H. W. Chem. Soc. Rev. 1988, 15, 309. Roesky, H. W.; Hesse, D.; Rietzel, M.; Noltemeyer, M. 2. Naturforsch. 1990, 45B, 72. Katti, K. V.; Seseke, U.; Roesky, H. W. Inorg. Chem. 1987,26, 814. (16) See for example: Imhoff, P.;Elsevier, C. J. J. Organomet. Chem. 1989,361, C61. Imhoff, P.; Nefkens, S. C. A.; Elsevier, C. J.; Goubitz, K.; Stan, C. H. Organometallics 1991, 10, 1421. (17) (a) Katti, K. V.; Cavell, R. G . Organometallics 1988, 7, 2236. (b) Katti, K. V.; Cavell, R. G . Organometallics 1989, 8, 2147. (c) Katti, K. V.; Cavell, R. G. Comments Inorg. Chem. 1990,10,55. (d) Katti, K. V.; Cavell, R. G. Inorg. Chem. 1989,28,3033. ( e )Katti, K. V.; Cavell, R. G. Organometallics 1988, 7, 2236. (0 Katti, K. V.; Batchelor, R. J.; Einstein, F. W. B.; Cavell, R. G. Inorg. Chem. 1990,29, 808. (18) Igau, A.; Dufour, N.; Mahieu, A.; Majoral J.-P.Angew. Chem., Int. Ed. Engl. 1993, 32, 95.

H+

Me,

/Ar

Me/P-N\ZrChCI 5

air- and moisture-sensitive powder 3 in 85% yield (Scheme 2). When the reaction is done in THF, formation of 3 is indicated by the change in color of the solution from red (2) t o green. The 31PNMR spectrum of 3 reveals the presence of a doublet of septets at -4.3 ppm ( 2 J p ~= 6.3 Hz). The signal for the Cp protons appeared in lH NMR as a doublet with the coupling constant 3&H = 1.4 Hz, consistent with a Cp-Zr-P ske1et0n.l~The lH NMR spectrum also suggests that each of the two methyl groups are bound to the phosphorus atom: only one doublet is detected for the two methyl groups ( 2 J ~ p= 6.3 Hz). 13C NMR corroborates this interpretation, because only one doublet is observed for the same groups (Ucp = 11.1 Hz). All these observations are in agreement with either a P-metalated iminophosphorane form (A) or the corresponding cyclic one (B).Attempts to obtain crystals suitable for crystallographic X-ray structure determination studies have so far failed. Me

I

Me-P=N -Ar

I

ZrCpzCl

A

Me

\

Me'

P-N-Ar

/ ZrCpzCl

B

The formation of 3 might involve the transient intermediate 4 (resulting from insertion of the chloroiminophosphane into the Zr-C bond of CpzZrMez), which rearranges by migration of the chlorine atom from phosphorus to zirconium and of a methyl group from zirconium to phosphorus. Note that in solution a t room temperature, 3 affords quantitatively the phosphane 5, which appears t o be the thermodynamically favored product of the reaction of 2 with CpzZrMez. Moreover, addition of pyridine or PMe3 to 3 gives 5. The 31PNMR chemical shift of 5 is in the expected range for aminophosphanes, while the lH NMR spectra shows, now, one singlet for the Cp protons. The Zr-N bond in 5 can be easily cleaved in the presence of proton donors (solvent, traces of water) to give the derivative 6. In order t o have a better idea of the structure of the kinetic product 3 (form A or B),we undertook the study of its reactivity, bearing in mind that azaphosphazirconiridines such as 7 are poorly reactive: only a few reactions involving 7 (ring opening or ring retention) have been reported to date.20 (19) Majoral, J.-P.;Dufour, N.; Meyer, F.; Caminade, A.-M.;Choukroun, R.; G e ~ a i sD. , J . Chem. Soc., Chem. Commun. 1990,507. Dufour, N.; Majoral, J.-P.; Caminade, A.-M.; Choukroun, R.; Dromzge, Y. Organometallics 1991, 10, 4. (20) Dufour, N.; Caminade,A.-M.; Basso-Bert, M.; Igau, A.; Majoral, J.-P. Organometallics 1992, 11, 1131.

Mahieu et al.

946 Organometallics, Vol. 14, No. 2, 1995

-

-

Scheme 3. Reactivity of 3 and 5 with Nitriles Me

I

(21)Tebby, J. C.; Krishnamurthy, S. S. In CRC Handbook of Phosphorus-31 Nuclear Magnetic Resonance Data; Tebby, J. C., Ed.; CRC Press: Boston, MA, 1990;Chapter 14, pp 409-477. (22) It has recently been shown that, for example, tert-butyl isocyanide reacts rapidly with the cationic zirconium complex CpzZr(CH& (THF)+(as the B P k - salt) to yield the iminoacyl isocyanide complex CpzZr{fW(=N-t-Bu)CH3}(CN-t-Bu)+: Guo, Z.; Swenson, D. C.; Guran, A. S.; Jordan, R. F. Organometallics 1994, 13, 766.

I

It

I \ .

-40'C

., C * w ZrCIhCI R'

'.

I

3

Ar

Me-P=N'

ZrCpzCl

7

Insertion Reactions into the P-Zr Bond. Derivative 3 reacts with l equiv of CH3CN in CHzClz at -40 "C to give instantaneously compound 8a via insertion of CH3CN into the P-Zr bond (Scheme 3). lH and 13C NMR strongly suggest the presence of a C-CH3 group in 8a;the 31PNMR spectrum (6 53.8 ppm) is in favor of a cyclic iminophosphorane form (with a dative bond between the iminophosphorane nitrogen atom and zirconium) rather than a linear form, which would give rise to a much more shielded chemical shifX21 However, considering these data, the formation of the aminophosphane 9 cannot be totally excluded. Nevertheless, the thermodynamic product 5 does not react even in the presence of an excess of acetonitrile (Scheme 3). It can also be noted that the azaphosphazirconiridines 7 are inert toward nitriles. Addition of i-PrCEN to 3 similarly gives the insertion product 8b. Another type of insertion product can be obtained by reacting paraformaldehyde with 3 at -40 "C; in this case the linear iminophosphorane 10 was quantitatively formed (Scheme 4). The 31PNMR chemical shift of 10 (6 -12.4 ppm) is in agreement with an acyclic P-N double-bonded structure.21 The lH NMR spectrum exhibits one doublet for methylene protons at 4.45 ppm with a phosphorus-hydrogen coupling constant of 7.0 Hz. The presence of a methylene group directly linked to phosphorus is confirmed by 13C NMR (6 (CH2): 76.8 (d, 'Jcp = 94.5 Hz)). Treatment of 3 with carbon disulfide at -40 "C provides an additional example of an insertion reaction into the phosphorus-zirconium bond with the formation of a third type of compound, the iminophosphorane 11 (Scheme 4). Two isomers can be distinguished by 31P NMR spectroscopy (lla,b: 6 -18.8 (70%)and -19.3 (30%) ppm, respectively). The 13C NMR spectrum of lla,b for the S-C-S carbon consists of doublets at 261.4 (JCP = 35.2 Hz) and 261.3 (JCP= 35.2 Hz) ppm, respectively. In marked contrast, the phosphane 5 as well as the three-membered-ring compound 7 do not react with paraformaldehyde or with carbon disulfide even under forcing conditions: no insertion reaction was observed in these cases. These observations demonstrate that the reactive species is the P-metalated iminophosphorane 3 and not the (zirconioamino)phosphane 5 and that 3 exists in a linear form (A) rather than in a cyclic one (B). 3 can be considered as the masked iminophosphide [MeZP=N2,4,6-t-Bu&sH2l[ZrCp2Cll, a newly identified species. Formal Insertion into the N-Zr Bond. Compound 3 is converted to the phosphane 12a by reaction with the isocyanide Me3SiCH2NC, in toluene at -78 "C (Scheme 5). The resonance signal for the sp2 imino carbon in 13C NMR appears at 207.1 ppm (d, 2Jcp = 43.3

-

+ R-CEN

Me-?=N-Ar

Me

8a, R=Me 8b. R = i-R

Me

I

Me -P= N -Ar I

Z ~ C ~ ~JC I

-

25 'CI

Me,

/Ar

Me,

+

P-N\ Me'

R-C=N*

ZrCp2Cl

5

,Ar

P-N, 25OC

Me'

,C=N R

\

ZrCpZCl

9

Scheme 4. Insertion Reactions into the P-Zr Bond

-

Me

Me -P=N -Ar I CH2-0,

ZrCpzCl 10

Me Me-P=N-Ar

I

P

'Z&l 1ln.b

Scheme 5. Reactivity of 3 and 5 with Isonitriles Me

Me,

I

+

Me-P=N-Ar 1 CpzClZr

:C=N-R

Ar P-N'

----)

Me'

3

'C Q \ N- ZrCpzCl

/

R

-

121, R = CHZSiMq

Me

12b,R = cyclohexyl

I

Me-P=N -Ar

I

CpzClZr 'C=N-R

I

13

I

It Me

I

13"

Me-F'N-Ar

J

+

CpzClZr 'c=N-R

Me,

13'

-

Ar

+ :C=N-R

P-N: Me'

ZrChCl

*

12

25 'C

5

Hz), and signals for the two Cp groups appear at 110.7 and 114.5 (s) ppm. An analogous reaction involving 3 and cyclohexyl isocyanide leads t o 12b. The X-ray structure determination of 12a (Figure 1 and Table 1)

Masked Iminophosphide Anion

Organometallics, Vol. 14, No. 2, 1995 947

Figure 1. Structure of 12a. Table 1. Crystallographic Data for 12a formula fw cryst syst space group Z

a, A

b, A

C,

A

A deg v, A3 F(O00) Dcalcd. g cm-3 cryst dimens, mm T,“C

Crystal Parameters C~~H~~CWZPS~Z~ 691.587 monoclinic P21/n 4 14.749(9) 15.521(8) 16.086(9) 90.4(2) 3680(5) 1468 1.247 0.30 x 0.20 x 0.15 20

Measurement of Intensity Data radiation Mo, 0.710 69 8, scan type 8/28 Bragg angle, deg 2.20 rangehdices (hkf) 0-14,O-15, -15 to +15 0.90 0.35 tan e scan width, deg no. of rflns for the refinement of the cell 25 no. of indep reflns 6812 no. of observed reflns 4130 no. of refined params 398 R(F2 0.0572 RdF2 0.0642

+

‘R = C(IIFoI

- IFcll)/C(IFol).

bRw

=

[C(IFol

- I~cl)z~Z(I~ol)21”z~

shows clearly the coordination of the imino nitrogen atom to the CpzZrCl center. Classical bond length and angle values are observed for 12a (Tables 2 and 3). The phosphorus-nitrogen bond length (1.773 A) confirms the phosphane structure.

Table 2. Selected Bond Distances (A) in 12a Zr( l)-C1(1) Zr(l)-C(ll) Zr( 1)-N( 1) N(l)-C(ll) N( 1)-C( 12)

2.558(2) 2.246(5) 2.178(5) 1.286(8) 1.453(8)

C(11)-N(2) N(2)-P( 1) N(2)-C(13) P(l)-C(23) P(1)-C(22)

1.380(7) 1.773(6) 1.467(8) 1.73(1) 1.84(1)

Table 3. Selected Bond Angles (deg) in 12a N(1)-Zr(1)-Cl(1) N(1)-Zr(1)-C(l1) N(l)-C(l l)-Zr(l) C(ll)-N(l)-Zr(l) C(l l)-N(2)-P(l) N(2)-C(ll)-N(l) N(2)-C(ll)-Zr(l)

82.6(1) 33.8(2) 70.2(3) 76.1(3) 116.2(4) 132.7(6) 157.1(5)

C(ll)-N(2)-C(l3) C(13)-N(2)-P(l) C(l2)-N(l)-C(ll) C(l2)-N(l)-Z~(l) N(2)-P(l)-C(22) N(2)-P(l)-C(23) C(22)-P(l)-C(23)

125.7(5) 116.2(4) 132.0(5) 150.8(4) 103.4(4) 108.7(5) 97.8(6)

At first sight, these results seem t o indicate that 12a (or 12b) arises from insertion of isocyanide into the nitrogen-zirconium bond and therefore that the reactive species here is the (zirconioamino)phosphane 5 and not 3. However, no reaction occurs when 5 is treated with Me3SiCHzNC or cyclohexylNC at room temperature. Moreover, it can be noted that the three-memberedring species 7 does not react with isocyanides. Therefore, it is reasonable to postulate that the first step of the reaction involving 3 and isocyanide is the coordination of the isocyanide on the vacant coordination site of the metal moieties to give 13. As we have already observed (addition of PMe3 or pyridine to 3;see above), coordination of a donor ligand can induce the dissociation of the P-Zr bond to afford 13‘;then electrophilic attackz3 of the metalated carbocation 13” (Scheme 5)

Mahieu et al.

948 Organometallics, Vol. 14, No. 2, 1995

Scheme 7. Reactivity of 3 and 5 with Eschenmoser's Salt and Triflate Derivatives

Scheme 6. Substitution Reactions on 3 Me HCPpyridine 1

-

- CprZrCl2

1

Me-P-N-Ar

I

14

3 + H~c=NM~CI

H

I

Me

Me

I

Me-P=N-Ar

I

+

Me-ALNK4r

I

22

I

I

-vMe Me-L;N-Ar I

I

Me -P =N -Ar

I

RR'P

t

5 + H2C=NMeZCI

-7+RC33T

16

25 'C

Me

23

15

Me

I

CI-

CH2NMe2

CH2NMe2

Me Me-P=N-Ar

3

-

Me

I+

Me-P-N

4

Ar /

OS02CF3'

H '

24. R = H 25. R = Me

Scheme 8

17. R = R'= Ph 18, R = R'= Me 19, R = N(i-Pr)z, R' = CI 20. R = R' = NM%

Me

I

Me- P-N-Ar

27

P=N-Ar Me

- CprZrcl2

Me-P=N-Ar

I

3

CI-P=N-Ar

-I Ar P-N,

PhzP=O

at the hard nitrogen nucleophilic center of the thermodynamically more stable aminophosphide Me2P-N-Ar (Ar = 2,4,6-t-Bu&sH2) gives 12a (or 12b). Indeed, compounds 12a,b are formally the first derivatives resulting from insertion of isocyanides into a N-Zr bond. To our knowledge such a reaction has not yet been reported. Reactions at Phosphorus. Exchange reactions easily occur when HC1-pyridine, methyl iodide, or Nbromosuccinimide (NBS) is added to 3 a t -78 "C (Scheme 6). Compounds 14-16 are isolated in nearquantitative yields. Such reactions take place when various chlorophosphanes RRPC1 are treated with 3 in THF at -78 "C. The formation of the expected phosphanyliminophosphoranes 17-20 was detected by 31P NMR (two doublets for each derivative (17, 6 -5.3 (PPh2) and -22.0 (Me2P=), l J p p = 259.8 Hz; 18,d -18.8 (Me2P=) and -53.0 (Me2P),l J p p = 240.0 Hz; 19,d 130.2 (i-PrNPC1) and -21.2 (Me2P=), l J p p = 320.0 Hz)), but during workup, compounds 17-19 decompose into a variety of species which were impossible to purify. It was only possible to isolate and fully characterize the phosphanyliminophosphorane20. The 31PNMR spectrum of 20 appears as two doublets a t 110.3 ((Me2NhP) and -14.2 (MezP=) ppm with typical l J p p coupling constants of 299.4 Hz. The structure of 20 was corroborated by lH and 13C NMR as well as by mass spectrometry. Under the same experimental conditions, the diphenylchlorophosphaneoxide reacts with 3 to give the expected compound 21 (Scheme 6). In contrast t o the reactions of 3 with methyl iodide, NBS, or chlorophosphanes which only lead to iminophosphoranes, addition of the Eschenmoser salt H2C=NMezCl to 3 at -78 "C affords a mixture of the iminophosphorane 22 and of the phosphonium salt 23 (Scheme 71, which were isolated and fully characterized. The formation of 22 can be easily explained via a (23) Gololobov, Y . G.; Swalova, E. A,; Chudakova, T. I. Zh. Obshch.

Khim. 1981,51,1433.

+

21

- CpZZrCl2

Me'

P'N-Ar 26

classical exchange reaction from the P-metalated iminophosphorane form 3, while the generation of the salt 23 might involve the (zirconioamino)phosphane 5. Indeed, 5 treated with HzC=NMezCl gives quantitatively the phosphonium salt 23. On the other hand, phosphonium salts 24 and 25 are quantitatively formed when 3 or 5 is reacted with triflic acid or methyl trifluoromethanesulfonate (Scheme 7). Like PMe3 or pyridine ligands, the trifluoromethanesulfonate anion may act as a catalyst for the rearrangement of 3 to 5. Formation of 23-25 results from the electrophilic attack of R+ (H+, Me+)at the phosphorus center of 5 followed by cleavage of the Zr-N bond in the presence of a source of protons (solvent, traces of water). Zirconium species have not been identified. Reaction at Nitrogen. Treatment of 3 with chloroiminophosphane 2 leads to the aminoiminophosphane 26 (Scheme 8). The 31PNMR spectrum of 26 consists of two doublets a t 322.4 (P-N) and 98.8 (Me2P) ppm with 2 J p p = 11.7 Hz. lH and 13CNMR corroborate the proposed structure. Two hypotheses can be formulated for the formation of 26. The first one may involve the preliminary exchange reaction between 3 and 2 affording 27 which further rearranges into 26, while the second one implies a direct exchange with the thermodynamically favored form 5. The 1,2-shift of a phosphorus group from phosphorus to the imino nitrogen has already been observed23and therefore cannot be totally ruled out. Nevertheless, the formation of 27 was never detected in 31PNMR even a t low temperature. Therefore, the direct grafting of 2 t o the nitrogen atom of the phosphane 5 seems to be more realistic. Coordination Chemistry of 3. Addition of NiCl2 or PdCl2 (0.5 equiv) to 3 (1equiv) leads to the formation of the new complexes 28a,b and not to the expected derivatives 29a,b (Scheme 9). A similar result is obtained when 5 is reacted with NiCl2 or PdClz under the same experimental conditions. Moreover, treatment

Organometallics, Vol. 14, No. 2, 1995 949

Masked Iminophosphide Anion

Scheme 9. Reactivity of 3 and 6 with Transition Metals Ar N' Me' \ / M Ar,N/--b.Me 'Me

Me 'p-

, I

+ IC! MCIz

30r5

Me. p/ M ":'e'

MC'2

Me.,/

2%. M = Ni 29b.M=Pd

2&.M=Ni ZSb,M=Pd

1 30

of 3 or 5 with W(C0)5THF gives rise to the 1:l complex 30. Indeed, in all of these experiments, 3 reacts as a phosphane and not as a P-metalated iminophosphorane.

Conclusion The first isolated P-metalated iminophosphorane, 3, appears to be a versatile and useful reagent, allowing the preparation of a large number of new free or complexed, neutral or cationic, acyclic or cyclic phosphorus compounds. Reactions with nitriles, paraformaldehyde, carbon disulfide, isocyanides, methyl iodide, N-bromosuccinimide, or various chlorophosphanes reveal that this P-metalated iminophosphorane, stable at -40 "C, acts as a masked iminophosphide: a new tricoordinated tetravalent phosphorus anion. Therefore, the transition-metal derivatization of [RzP-NR'l- considerably affects its reactivity as compared with the alkali-metal derivatives, which react as phosphinoamide anions RzPNR with the negative charge located on nitrogen. On the other hand, the thermodynamically favored form of 3,i.e. the (zirconioamino)phosphane5, is the reactive species when 3 is reacted with triflic acid, methyl trifluoromethanesulfonate, chloroiminophosphane, NiC12, PdC12, or W(C0)5THF,while the Eschenmoser salt H2C-NMe2Cl reacts with both 3 and 5. Attempts to prepare other P-metalated iminophosphoranes, stable a t room temperature, as well as the use of these new reagents in organic and organometallic chemistry, are underway.

Experimental Section All manipulations were carried out with standard highvacuum or dry argon atmosphere techniques. NMR spectra were recorded at ambient temperature on 200- and 250-MHz Bruker spectrometers and referenced as follows: 'H (6) CHDClz (5.32), C6HDs (7.16);13C{lH} (ppm) CDzClz (53.8), (0.0 ppm). Chemical c a s (128.0);31P{1H} external 85% shifts are in 6 ('HI or ppm (I3C, 31P),and coupling constants (4 are in hertz. Mass spectra were obtained on a Nermag R10-1OH. Microanalyses have been performed by the Centre de Microanalyse du CNRS or in our laboratories. Melting points were determined in evacuated capillaries and were corrected and calibrated.

Solvents were purified as follows: THF and ether was distilled from Na/O=CPhz, CHzClz was distilled from PzOS,and pentane was distilled from CaHz. c& and CDzClz, purchased from CEA, were treated with LiAlH4, distilled, and stored under argon. Reagents were obtained as follows: acetonitrile was distilled from CaH2; CSz (Fluka) was passed through activated alumina prior to use; (CHzO),, Me3SiCHzN=C, CsH11N=C, i-PrCN, HCEpyridine, MeI, PhZP(O)Cl, PhZPC1, HZC=NMeZCl, HOSOzCF3, MeOSOzCF3, NiClz (Aldrich),MezPC1 (Strem), N-bromosuccinimide (Fluka), and PdClz (Lancaster) were used as received; CpzZrMezZ4 and 226 were prepared by literature methods. Me*(ZrCp&l)=N-2,4,6-t-Bu~C&~(3). To a solution of chloroiminophosphane 2 (0.326 g, 1.00 mmol) in pentane (10 mL), cooled to -40 "C, was added CpzZrMez (0.251 g, 1.00 mmol) in pentane (10 mL) at -40 "C. The mixture was stirred for 30 min, after which a white precipitate separated from the solution. The white powder was washed twice with pentane (10 mL, -40 "C) and dried under vacuum. This afforded 3 (0.491 g, 0.85 mmol) in 85%yield. 31P{1H} NMR (CDZClz): -4.3. 'H NMR (CDzClz): 7.28 (s, CHh), 6.00 (d, 3 J =~1.4, Cp), 1.53 (8, 0-t-Bu), 1.34 (9, p-tBu), 0.80 (d, 2 J =~6.3, MeZP). 13C{'H} NMR (CDzC12): 148.8 (d, 'Jcp = 18.0, i-Ck), 146.5 (d, 3 J ~ = p 6.0, o - C ~ )138.9 , (d, Vcp = 5.0, p-Ch), 120.7 (8, m-Ch), 110.9 (9, Cp), 36.5 (8, o-CCH~),36.1 ( 8 , p-CCHs), 33.6 (8,o-CCH~),30.8 (9, P-CCH~), 16.7 (d, lJcp = 11.1, MeZP). Me#-N(ZrCp&1).2,4,6-t-B~Ca~(6). A solution of 3 (0.200 g, 0.35 mmol) in CHzClz (15 mL) was stirred at room temperature for 4 h, which after removal of the solvent gave the white powder 5 (0.200g, 0.35 mmol) in quantitative yield. 31P{'H} NMR (CDzClz): 31.8. 'H NMR (CDzClz): 7.33 (8, C H d , 6.32 (8,Cp), 1.47 (9, o-t-Bu), 1.40 (d, V H= P5.8, MezP), 1.29 (s,p-t-Bu). '3C{'H} NMR (CDZClZ): 146.7(8, o - C ~ )144.8 , (9, p-Ch), 121.7 (8, m-Ck), i-Ch not observed, 114.3 (8,Cp), 34.9 (8, o-CCH~),34.5 (8,P-CCH~),30.3 (8, O-CCH3), 31.7 (s, p-CCH3), 20.4 (d, ~ J C P = 17.5,MezP). Me*-N(H)-2,4,6-t-B~CsHa (6). Attempts to isolate 5 by treatment with pentane and THF gave the phosphane 6 in quantitative yield. 3'P{lH} NMR (CDZClz): 33.3. 'H NMR (CDzClz): 7.48 (s, CHh), 3.10 (d, ' J H = ~ 5.8, NH), 1.56 (8,0-t-Bu), 1.33 (8,p-tBu), 1.09 (d, 2 J =~6.5,MeZP). 13C{'H} NMR (CDzClz): 144.5 (d, 'Jcp = 3.0, Z-Ck), 143.8 (d, 4 J ~ = p 2.2,o - C ~ )141.9 , (d, 'JCP = 14.0,p-Ch), 123.6 (d, Vcp = 1.7, m-Ck), 36.8 (9, o-CCH~), 34.8 (8,P-CCH~),33.2 (8, O-Cms), 31.9 (s,P-CCH~),20.0 (d, dcp = 19.5, MezP). IR (cm-l, KBr pellet): YNH 3283 b. MS (EI): m l z 321 (M+). Anal. Calcd for CzoH36NP: C, 74.72;H, 11.28. Found: C, 74.44; H, 11.45. M ~ ~ P ( M ~ C = N - Z ~ C ~ ~ C ~ ) = N - ~ ,@a). ~ , ~ Ac-~-BQC&& etonitrile (10 mL) was added to 3 (0.288 g, 0.50 mmol) maintained a t -30 "C. The resulting solution was stirred for 1 h. The precipitate formed during this reaction was isolated by filtration, washed twice with 10 mL of acetonitrile at -30 "C and then with pentane (2 x 10 mL, -30 "C). The resulting was dried under vacuum white powder 8a (0.309g, 0.50 "01) (quantitative yield). 31P{1H) NMR (C6De): 53.8. 'H NMR (CsDs): 7.51 (9, CHk), 6.05 (8, Cp), 1.70 (d, 3 J =~0.9, MeCP), 1.53 (s, o-t-Bu), 1.25 (8, p-t-Bu), 1.20 (d, = 8.8, MeZP). I3C{lH} NMR (C&): 165.0 (d, 'Jcp = 14.4 Hz, PC=N), 148.4 (8, o - C ~ )148.1 , (8, p-Ch), 136.6 (8,i-C& 126.4 (9, m-Ch), 111.6 (8, Cp), 35.1 (s, o-CCH~),34.7, 34.6 (9, O-Cm3), 32.4 (s, p-CCHd, 31.8 (s, p-CCH3), 28.3 (s, PCMe), 16.9 (d, lJcp = 25.3, MeZP). Anal. Calcd for C~ZI&CI&PZ~:C, 62.15;H, 7.82. Found: C, 62.42; H, 8.05. MenP(i-PrC=N-ZrCpaCl)=N-2,4,6-t-B~c~~ (8b) was prepared by the same procedure as for 8a: i-PrC=N ( 5 mL), (24) Samuel, E.; Rausch, M. D. J . Am. Chem. SOC.1973,95,6263. (25) Niecke, E.; Nieger, M.; Reichert, F. Angew. Chem. Znt.,Ed. Engl. 1988,12, 1715.

950 Organometallics,

Vol. 14,No.2, 1995

3 (0.360 g, 0.62 mmol). 8b was obtained as a white powder (0.403 g, 0.62 mmol) in quantitative yield, mp 126-127 "C dec. 31P{1H}NMR (C6Ds): 49.3. 'H NMR (C6D6): 7.48 (9,CHh), 6.21 ( 8 , Cp), 2.61 (sept, 3Jm = 6.7, CHCHd, 1.50 (s,o-t-Bu), 1.34 (s,p-t-Bu),1.19 (d, 2Jm= 8.8, MezP), 1.08 (d, 3 J =~6.7, CHCH3). '3C{lH} NMR (C6D6): 171.5 (d, ' J c p = 15.1,PC-N), 148.8 (s, o - C ~ ) 148.3 , ( 8 , p-Ch), 135.2 (d, 'JCP = 4.5, i - c ~ r ) , 127.1 ( 8 , m-Ch), 112.6 ( 8 , Cp), 34.7, 34.6 (9,O-CCH3), 32.4 (s, p-CCH3), 31.8 (s, o-CCH~),31.7 (s,p-CCH3), 22.8 ( 8 , CH3CH), 18.6 (d, l J c p = 27.5, MezP). Anal. Calcd for C34H52ClN2PZr: C, 63.17; H, 8.11. Found: C, 63.48; H, 8.56. General Procedure for the Preparation of Iminophosphoranes 10, 11,12a,b, and 14-21. To a solution of 2 (0.325 g, 1.00 mmol) in THF (5 mL) at -78 "C was added CpzZrMez (0.251 g, 1.00 mmol) dissolved in 10 mL of THF. The mixture was warmed to room temperature and then cooled to -78 "C. To this solution was added paraformaldehyde (0.030 g), carbon disulfide (0.076 g, 1.00 mmol), (trimethylsily1)methyl isocyanide (0.113 g, 1.00 mmol), cyclohexyl isocyanide (0.109 g, 1.00 mmol), HC1-pyridine (0.092 g, 0.80 mmol), methyl iodide (0.062 mL, 1.00 mmol), N-bromosuccinimide (0.192 g, 1.08 mmol), or chlorophosphane (1.00 mmol). The resulting mixture was warmed to room temperature and was stirred for 2 h. Evaporation of the solvent followed by washing the residue with pentane (2 x 10 mL) led either to a powder or an oil. Mep(CH20ZrC!paCl)=N-2,4,6-t-Bu&d32(10): white powder, 0.607 g, quantitative yield. 31P{1H}NMR (C6D6): -12.4. 'H NMR (C6D6): 7.59 ( 8 , CHh), 5.83 (s, Cp), 4.45 (d, 'JHP= 7.0, CHzO), 1.66 (s, o-t-Bu), 1.43 (s,p-t-Bu), 1.26 (d, 'JHP= , (d, 'JCP 11.4, MeZP). l3C NMR (C6D6): 150.7 (s, i - c ~ r )141.7 = 3.0, o - C ~ ) 139.1 , (s, p-Ch), 122.1 (d, 4 J ~ = p 10.0, m-Ch), = 94.5, PCHzO), 36.3 (s, o-CCHd, 113.6 (s, Cp), 76.8 (d, 'JCP 34.7 (s, p-CCHs), 32.2 (s,p-CCH31, 31.6 (s, o-CCH~),15.3 (4 lJcp = 67.3, MeZP). Anal. Calcd for C31H47ClNOPZr: C, 61.30; H, 7.80. Found: C, 61.01; H, 7.92. Me2P(CS&rCpzCl)=N-2,4,6-t-B~&&2(11): two isomers, green powder, quantitative yield. lla: 31P{'H} NMR (C6D6): -18.8 ppm; 'H NMR (CsD6) 7.63 (9, C&), 5.68 (S, CP), 1.65 (s, o-t-Bu), 1.64 (d, 'JHP = 11.9, MeZP), 1.40 (s, p-t-Bu); 13C{'H} NMR (C6D6) 261.4 (d, ' J c p = 35.2, P-c=s), 142.5 (S, o-Ch), 140.4 (s,p-Ch), 122.4 ( 8 , m - C d , 113.0 (8,CP), 36.7 (s, o-CCH~),33.6 ( 8 , p-CCH31, 32.4 (s,p-CCHd, 33.1 (9,O-CCHd, 19.7 (d, l J c p = 82.7, MezP). llb: 31P{'H} NMR (C&) -19.3; 'H NMR (CsD6): 7.63 (S, CHh), 5.48 (s, Cp), 1.66 (s, o-t-Bu), 1.65 (d, 2 J =~10.9, MezP), 1.62 (8,p 4 - B ~ ) 13C{'H} ; NMR (C6D6) 261.3 (d, 'JCP = 35.2, , (s, p-Ch), 122.4 (s, m-Ch), P-C=S), 142.4 (s, o - C ~ ) 140.1 109.4 ( 6 , Cp), 36.7 (s, o-CCH~),33.6 (s, p-CCHd, 32.4 ( 8 , p-CCH3), 32.1 (9,o-CCH~),19.3 (d, 'JCP = 83.0, MezP). Anal. Calcd for C31HaClNPSzZr: C, 56.97; H, 6.94. Found C, 56.62; H, 6.52. Me~-N[C(ZrCpzCl)=NCH2SM~l-2,4,6-t-B~C& (12a): white powder, 0.655 g, 95% yield. 31P{1H}NMR (CsDs): 67.9. 'H NMR (CsDs): 7.46 (s, CHh), 6.09 (5, ($1, 2.91 ( 8 , CH2Si), 1.46 (s, o-t-Bu), 1.22 (s, p-t-Bu), 1.04 (d, VPH= 8.5, MezP), 0.24 ( 8 , SiMe3). l3C{'H} NMR (C6Ds): 207.1 ('JcP = 43.3, P-N-C=N), 148.8 (6, O - C ~ )148.3 , (s, p-Ch), 136.4 (s, i-Ch), 126.8 (s, m-Ch), 114.5, 110.7 (9, Cp), 42.3 ( s , CHzSi), 38.5 (s, P-CCH~),35.1, 35.0 (s, O-Cm3), 34.7 (s, o-CCH~),31.5 (s, p-CH3-C), 17.8 (d, l J c p = 27.1, MezP),1.1(s, SiMe3). IR (cm-l, THF): Y C N 1601 s. Anal. Calcd for C35H&lNzPSiZr: C, 60.87; H, 8.17. Found: C, 60.66; H, 8.10. MezP-N[C(ZrCp2C1)=NC~H~~I-2,4,6-t-Bu&eH2 (12b): white powder, 0.618 g, 90% yield. 31P{1H)NMR (CDzClz): 69.2. 'H NMR (CDzC12): 7.75 (s, CHh), 6.24 (s, Cp), 3.00 (s, HCN), 1.67-1.32 (m, CHz), 1.54 (s, o-t-Bu), 1.36 (s, p-t-Bu), = 8.6, MezP). 13C{'H} NMR (CDzClz): 204.2 1.00 (d, 'JPH ('Jcp = 45.5, C=N), 148.2 (s,p-Ch), 147.6 (s, o - C ~ )135.1 , (s, i-Ch), 127.0 (s, m-Ch), 110.1 (s, Cp), 57.1 (s, C=NCH), 38.3 (s, o-CCH3), 34.8 and 34.7 (s, O-Cm3), 32.3 ( 8 , p-CCHs), 31.5 (s, 0-CHz), 31.1 (s, p-CCHs), 25.4 (s, P-CHZ),25.3 (s, m-CHd,

Mahieu et al. 18.1(d, l J c p = 26.2, MeZP). Anal. Calcd for C37H5sClNzPZr: C, 64.73; H, 8.22. Found: C, 64.34; H, 8.56. Me2P(H)=N-2,4,6-t-B~&&(14):white powder, 0.231 g, 90% yield. 31P NMR (C6D6): 8.8 ('JPH = 598.6). 'H NMR (CsDs): 7.38 (s, CHh), 3.21 (d, ' J H=~ 598.6, PH), 1.39 (s, 04Bu), 1.37 (s,p-t-Bu),1.33 (d, 2Jm= 16.9, MezP). 13C{'H) NMR (CsD6): i-Ch not observed, 141.9 (S, P-Ch), 134.2 (S, 0-Ch), 122.1 (s, m-Ch), 34.3 (d, l J c p = 86.5, MezP), 34.8 (s,p-CCH3), 32.4 (s, p-CCH3), 31.9 ( 8 , o-CCH~),30.8 (s, o-CCH3). Anal. Calcd for CzoH36NP: C, 74.72; H, 11.28. Found: C, 74.66; H, 11.63. Me#=N-2,4,6-t-Bu&a2 (15):white powder, 0.302 g, 90% yield. 31P{'H) NMR (CsD6): -22.4. 'H NMR (CsDs): 7.16 (s, CHh), 1.62 (s,o-t-Bu), 1.45 (s,p-t-Bu), 1.09 (s,'JPH = 11.4, Me3P). l3C{'H} NMR (C6D6): 142.1 (d, 3Jcp = 4.3, o-ch), 14.2 (s, i-Ch), 139.2 (d,p-Ch,),122.2 ( s , m-Ch), 36.5 (s, o-CCH3 and p-CCHs), 32.5 (s, P-CCH~),31.7 (s, o-CCH~),20.1 (d, 'Jcp = 74.3, Me3P). Anal. Calcd for C21H38NP: C, 75.17; H, 11.41. Found: C, 75.56; H, 11.12. Me2P(Br)=N-2,4,6-t-Bu&Hz (16): pale brown powder, 0.360 g, 90% yield. 31P{1H} NMR (CsD6): -25.4. 'H NMR (C6D6): 7.51 (s, C&), 1.79 (d, 'JHP = 14.0, MezP), 1.50 (s, o-tBu), 1.41 (s,p-t-Bu). 13C{'H} NMR (C6D6): 140.7 (S, i-Ch), 140.6 (s, o-Ch,), 140.3 ( s , p - C d , 121.9 (s, m-Ch), 35.9 (s, p-CCHs), 34.7 (s, o-CCH~),32.1 (s, p-CCHs), 31.6 (s,o-CCH~), 20.6 (d, 'Jcp = 95.0, MeZP). Anal. Calcd for CzoH35BrNP: C, 59.99; H, 8.81. Found: C, 60.35; H, 8.51. Iminophosphoranes (17-20, 21) were obtained as oils. Only iminophosphorane 20 (0.374 g, 85% yield) was fully characterized. 17: 31P{1H}NMR (C&) -5.3 (d, 'Jpp = 259.8, PhzP), -22.0 (d, 'JPP = 259.8, MezP=). 18: 31P{1H} MMR (C6D6) -18.8 (d, 'JPP = 240.0, MezP=), -53 (d, J p p = 240.0, MezP). 19: 31P{1H}NMR (C6D6) 130.2 (d, 'Jpp = 320.0, i-PrzNPCl), -21.2 (d, l J p p = 320.0, MeZP=). 20: 31P{1H}NMR (C6D6) 110.3 ('Jpp = 299.4, MezNP), -14.2 (d, l J p p = 299.4, MezP=); NMR (C6Ds) 7.43 (s, C H d , 2.45 (dd, 3 J ~ p= 8.6, 4JHp = 6.0, NMeZ), 1.64 (s, o-t-Bu), 1.52 (dd, z J =~12.0, 3 J ~ = p 6.0, MezP), 1.40 ( s ,p-t-Bu); 13C{'H} NMR (CsD6) 144.6 (S, i-ch), 142.3 (S, 0-ch),138.7 (5,p-ch),121.4 (s, m-Ch), 44.0 (dd, VCP= 16.0, VCP= 7.5, NMez), 36.7 (s, 0-CCHs), 34.8 (s,P-CCH~),32.5 (s, P-CCH~),32.2 (s,o-CCH~), 21.8 (dd, l J c p = 57.3, UCP= 21.7, MeZP). Anal. Calcd for C24H47N3Pz: C, 65.57; H, 10.77. Found: C, 65.83; H, 10.34. 21: 31P{1H}NMR (C6D6) 27.2 (d, 'Jpp = 67.0, PhzP=O), -28.1 (d, l J p p = 67.0, MezP). MeaP(CHzNMez)=N-2,4,6-t-Bu~C~2 (22) and [Me@ (CH~NM~~)-N(H)-~,~,~-~-BU~C&~I+C~(23). To a suspension of H&=NMe2Cl(O.149 g, 1.60 mmol) in THF (5 mL) at 0 "C was added 3 (0.521 g, 0.80 mmol) in THF (5 mL). The mixture was warmed to room temperature and filtered and the solvent evaporated to dryness. The resulting powder was washed with pentane (3 x 5 mL) to extract 22. Compound 23 remained insoluble in pentane and was extracted with THF (3 x 5 mL). 22 (0.227 g, 0.59 mmol, 70%): 31P{1H}NMR (C6D6) -13.6; = 8.0, CHzP), 1.87 'H NMR (C6Ds) 7.57 (5,CHk), 2.59 (d, 'JHP (s, M e a ) , 1.64 (s, o-t-Bu), 1.44 (s,p-t-Bu), 1.33 (d, 'JHP = 11.5, Me2P); l3C{lH) NMR (C&) 150.3 ( s , i-ch), 142.1 (s, 0-ch), 139.2 (s, p-Ch), 122.2 (s, m-Ch), 61.6 (d, 'JCP = 94.2, CHzP), 48.2 (d, 3 J ~ = p 6.5, MezN), 36.6 ( s , o-CCH~), 35.0 (s,p-CCH3), 32.4 (s,p-CCH3), 31.9 (s, o-CCH~),16.7 (d, 'JCP = 71.8, MezP). Anal. Calcd for C Z ~ H ~ ~ NC, Z P72.97; : H, 11.45. Found: C, 73.25; H, 11.14. 23 (0.081 g, 0.16 mmol, 20%): mp 90 "C; 31P{1H} NMR = 9.2, NH), 7.38 (6, (C6Ds) 51.7; 'H NMR (C6D.5)7.56 (d, 'JPH CHk), 3.75 (d, VHP = 6.0, CHzP), 1.92 ( s , NMez), 1.88 (d, 2 J ~ = 13.5, MezP), 1.42 ( s ,p-t-Bu), 1.24 ( s , o-t-Bu); l3C{lH) NMR (&De) 151.4 (O-Ch), 149.2 @-Ch), 124.6 (m-C!h), 56.0 (d, 'Jcp = 85.0, CHZP),47.9 (d, VCP = 7.73, NMez), 37.4 (o-CCH~), 35.1 (P-CCH~),34.4 (o-CCH~), 31.76 (p-CCHs), 11.4 (d, ' J c p = 64.7,

Masked Zminophosphide Anion

Organometallics, Vol. 14, No. 2, 1995 951

Table 4. Positional Parameters and Equivalent Thermal MezP). Anal. Calcd for C23HuINzP: C, 54.54; H, 8.75. Parameters" Found: C, 54.17;H, 8.97. [M~~P(H)-N(H)-~,~,~-~-B~SC&I+OSOZCF~(24). To a atom xla ylb '?IC U(iso), A 2 solution of 3 (0.577g, 1.00mmol) prepared as above, in THF 0.0392 0.23740(4) 0.25466(5) 0.24495(4) (10mL) was added triflic acid (0.150mL, 1.00 mmol) at -78 0.0621 0.1376(1) 0.1549(2) 0.1634(1) "C. The solution was warmed t o room temperature and then 0.0673 0.3779(2) 0.3190(2) 0.4827(2) evaporated to give a white paste, which was washed with 0.0489 0.0171(1) 0.1403(1) 0.3727(1) 0.0343 pentane (3 x 10 mL). 24 was obtained as a white powder 0.1861(3) 0.2103(3) 0.3614(3) 0.0407 0.2747(3) 0.2793(3) 0.4753(3) (0.448g, 0.95 mmol, 95%). 0.0630 0.3965(5) 0.2571(6) 0.2000(5) 31PNMR (CDZClz): 32.3 (d, 'JPH= 518.0). 'H NMR (CDz0.0583 0.3583(5) 0.2162(6) 0.1271(5) Clz): 7.36(s,CHh), 7.31(d, 'JHP = 518.0,PH), 5.83 (d, VIP= 0.0643 0.3272(5) 0.1386(6) 0.1563(6) 9.9,NH), 1.86(d, = 14.0,MeZP), 1.40(s, o-t-Bu), 1.26( 8 , 0.0572 0.3460(5) 0.1285(5) 0.2472(5) p-t-Bu). l3C{'H} NMR (CDzClZ): i-Ck not observed, 149.9( 8 , 0.0567 0.3902(5) 0.2016(6) 0.2733(5) p-Ch), 134.0(d, 4 J ~ = p 5.0,m-Ch), 121.9(d, 3 J ~ = p 2.0,o-CAT), 0.0666 0.1495(8) 0.3552(6) 0.1454(7) 36.7 (9, 0-CCH3), 34.8 (9, P-CCH~),32.8 (8, O-Cm3), 30.3 (8, 0.0753 0.1443(7) 0.3814(6) 0.2344(7) p-CCH3), 7.7 (d, lJcp = 67.2,MeZP). Anal. Calcd for CZI0.0756 0.220(1) 0.4135(7) 0.2577(7) 0.0884 0.2710(8) 0.4079(8) 0.190(1) H37F3N03PS: C, 53.49;H, 7.91. Found: C, 53.73;H, 7.59. 0.0839 0.228(1) 0.3707(8) 0.1186(7) [MesP-N(H)-2,4,6-t-Bu3CsHzlfOSO~CFs(25) was pre0.0331 0.2464(4) 0.2579(4) 0.3897(4) pared by the same procedure as for 24 with methyl trifluo0.0458 0.1300(5) 0.1526(5) 0.4086(4) romethanesulfonate (0.164g, 1.00mmol): 0.461 g, 0.95mmol, 0.035 1 0.2366(4) 0.2528(5) 0.5610(4) 0.6023(4) 0.6922(4) 0.7402(4) 0.6962(4) 0.6066(4) 0.3035(5) 0.3156(5) 0.4801(6) 0.5993(6) 0.427l(9) 0.5613(4) 0.8409(4) 0.5735(4) 0.630(1) 0.460(1) 0.488( 1) 0.569(1) 0.529(1) 0.61 l(2) 0.8782(5) 0.8970(5) 0.8475(6) 0.4745(5) 0.5894(6) 0.6288(6)

95%.

0.309l(4)

0.1793(4)

0.0391

31P{1H}NMR (CDzClz): 53.8. 'H NMR (CDzC12): 7.34 ( 8 , 0.0493 0.1577(5) 0.2919(5) CHh), 6.06(d, % 7 ~ p= 9.8,NH), 1.86(d, 2 J= ~ 13.0,Me3P), 0.0441 0.1897(5) 0.2240(5) 0.0436 0.2413(5) 1.39(s,o-t-Bu), 1.25(~,p-t-Bu).13C{'H} NMR (CDzClz): i-C, 0.1686(5) 0.0400 0.2655(5) 0.1784(4) not observed, 150.6 (d, 5 J ~ = p 3.0,p - C d , 149.5 (d, 4 J c ~= 5.0, 0.0659 0.0013(6) 0.0417(6) m-Ch), 124.5(d, 3Jcp = 2.0,o - C ~ )37.0 , (s,o-CCH~),34.9 (5, 0.0698 -0.027 l(5) 0.2366(6) p-CCH3), 33.3 (s, O-Cm3), 31.2 (s, P-CCH~),13.6(d, 'JCP= 0.0723 -0.0390(6) 0.1221(6) 67.0,Me3P). Anal. Calcd for C Z Z H ~ ~ F ~ N OC, ~ P54.42; S : H, 0.0888 0.3852(8) 0.3599(9) 8.09. Found: C, 54.20;H, 8.28. 0.1163 0.3826(8) 0.4174(9) Me2P-N(P=N-2,4,6-t-Bu~C&I~)-2,4,6-t-BmCd-h (26). A 0.0467 0.1327(5) 0.3877(5) solution of CpzZrMez (0.252g, 1.00mmol) in toluene (15mL) 0.0473 0.1675(5) 0.2070(5) 0.0460 was reacted with 2 (0.326g, 1.00mmol) in toluene (5 mL) at 0.3 181( 5 ) 0.1010(5) 0.0615 0.075(1) 0.434(1) -78 "C. The reaction mixture was stirred for 15 min at -78 0.0674 0.147(1) 0.409(1) "C, and then 2 (0.326g, 1.00 mmol) in toluene (5 mL) was 0.0526 0.073(1) 0.355( 1) added dropwise at -78 "C. After 30 min at -78 "C, the 0.0722 0.041(1) 0.37 1(1) reaction mixture was warmed t o room temperature. After 2 0.0781 0.194(1) 0.453(1) h at room temperature, the solvent was removed and the 0.0798 0.152(2) 0.472(1) residue was extracted with pentane (10mL). Evaporation of 0.0767 0.113l(6) 0.2779(7) the solvent gave 26 as a red oil (0.550g, 0.90 mmol, 90%). 0.0653 0.2459(6) 0.2015(7) 31P{1H}NMR (CDzClZ): 322.4(d, 'Jpp = 11.7,P=N), 98.8 (d, 0.0890 0.1190(7) 0.1232(7) 0.0510 0.3408(5) 0.0999(5) = 11.7, PMez). 'H NMR (CDZClz): 7.65 (s, P=NCHh), 0.0725 0.2677(7) 0.0181(5) 7.58 (5, PNCHh), 1.77(s,PcN-p-t-Bu), 1.65 ( 8 , PeN-o-t-Bu), 0.0697 0.3998(6) 0.0956(7) 1.43(s, P=N-o-t-Bu), 1.34(s, FN-p-t-Bu), 1.22(d, ' J H=~ 17.8, MeZP). Anal. Calcd for C & ~ ~ N Z P Zc, : 74.71;H, 10.56. aCarbons C(27), C(28), C(29), C(30), C(31), and C(32), as well as Found: C, 74.52;H, 10.22. hydrogens bonded to these carbons, were refined with a multiplicity of 0.5. [Me2P-N(H)-2,4,6-t-Bu&H2]2NiCl2 (28a). To a suspen134 and 33.6(p-Ch), 124.0and 123.7(m-Ch),15.5(VCP = 16.1, sion of NiClz (0.065g, 0.50 mmol) in THF ( 5 mL) was added 3 MezP). MS (DCI, CH4): m l e 821 ([M 119. Anal. Calcd for (0.577g, 1.00mmol) in THF (10mL) at -78 "C. The mixture was warmed to room temperature and then stirred for 5 h. C40H,zClfi2PzPd: C, 58.56;H, 8.84.Found: C, 58.87;H, 8.24. [MeaP-N(H)-2,4,6-t-Bu&&lW(CO)a (30). To a solution After evaporation of the solvent, the residue was washed with pentane (20 mL). Filtration and evaporation of the solvent of 3 (0.577g, 1 mmol), prepared as above, in THF (10 mL) was added W(C0)5THF (0.175g, 1 mmol) in THF (60mL) at gave 28a as a red powder (0.695g, 0.90mmol, 90%). -78 "C. The mixture was stirred for 30 min at -78 "C and 31P{1H}NMR (C6D6): 45.0. 'H NMR (C6D6): 7.41 (6,CHh), then warmed to room temperature. The solution was stirred 4.72 (d, 'JHP = 10.0,NH), 4.77(d, ' J H = ~ 10.0,NH), 1.68(s, for 3 h and then evaporated t o give a residue which was o-t-Bu), 1.37 (d, z J =~3.1,MezP), 1.35 (d, VHP = 3.1, MezP), washed with pentane (20mL). Filtration and evaporation of 1.30(s,p-t-Bu). l3C{'H} NMR (C&): i-cp not observed, 147.5 pentane gave 30 as a yellow oil (0.613g, 0.95 mmol, 95%). (s, o - C ~ )144.4 , (s, p-Ch), 120.8 (s, m-Ch), 34.8 (s, o-CCH~), 31P{1H}N M R (C6D6): 35.1. 'H NMR (C6D6): 7.33 (9, CHh), 32.2(s, p-CCHs), 31.3 (s, O-Cm3), 29.1 (s, P-CCH~),11.6 (d, 3.56 (9, NH),1.36( 8 , o-t-Bu), 1.29 (d, VHP = 4.8,MezP), 1.26 'Jcp = 14.0,MeP), 11.3 (d, 'Jcp = 14.0,MeP). MS (DCI, 13C{'H} NMR (CsD6): 199.9(d, 'JPCO = 21.0,CO), CHI): m l e 774 ([M I]+).Anal. Calcd for C ~ O H ~ Z C ~ ~ N Z N ~(~,p-t-Bu). PZ: 197.8 (d, 'JPCO= 7.6,CO), 149.8(d, 3Jcp = 3.0,o - C ~ )147.9 , C, 62.18;H, 9.39. Found: C, 61.95;H, 9.52. (s,p-Ch), 132.2 ('Jcp = 9.0,o - C ~ )124.2 , (9, m-Ch), 38.2 (s, [Mefl-N(H)-2,4,6-t-B~~C&ld'dCl~(28b). To a suspen0-CCH3), 34.7(s,p-CCHs), 34.4(9, o-CCH~), 31.8( 8 , P-CCH~), sion of PdClz (0.088 g, 0.50 mmol) in THF (5 mL) was added 24.0 (d, 'JCP = 32.0,MezP). IR (cm-', THF): YCO 1931,1974 3 (0.577g, 1.00mmol) in THF (10mL) at -78 "C. The mixture s. MS (DCI, CHI): m l e 647 ([M 119. Anal. Calcd for was warmed to room temperature and then stirred for 24 h. CZ&~NO~PW:C, 46.52;H, 5.62. Found: C, 46.02;H, 5.98. The residue obtained after evaporation of the solvent was Structure Determination of 12a. A clear colorless crystal washed with pentane (30mL) and then filtered. Evaporation was used for data collection on an ENRAF-Nonius CAD 4 of the solvent gave 28b as a brown powder (0.656g, 0.85"01, diffractometer using molybdenum radiation. Lattice param85%). eters were determined from 25 centered reflections within 8 31P{1H}NMR (C&hj): 52.1. 'H NMR (C6D6): 7.38(S,CHh), < 0 < 15". The measurement was corrected by taking into 5.16(9, NH), 1.58(s,o-t-Bu), 1.28(9, p-t-Bu), MezP (complex). account Lorentz and polarization factors; absorption correction 13C{'H} NMR (C6D6): i-Ch not detected, 151.3,150.9 ( o - C ~ ) ,

+

+

+

Mahieu et al.

952 Organometallics, Vol. 14,No. 2, 1995 was performed using the Difabs program. The structure was solved using the CRYSTALS package. All non-hydrogen atoms were refined with anisotropic parameters. Hydrogen atom positions were located using a difference Fourier map and recalculated; their contributions were introduced in the calculation but not refined. One of the tert-butyl groups (central atom C(24)) was disordered. For the sake of clarity, only one of the two positions is shown on the ORTEP view. The final difference Fourier map did not show any peak higher than 0.7 e/&. Positional parameters and equivalent thermal parameters appear in Table 4.

Acknowledgment. Thanks are due to the CNRS for financial support of this work. Supplementary Material Available: Tables of bond length and angle values, anisotropic thermal parameters, and H atom positional parameters for 12a (13 pages). This material is contained in many libraries on microfiche, immediately follows this article in the microfilm version of the journal, and can be ordered from the ACS; see any current masthead page for ordering information. OM940717T