Controlling the number of metal sites to which a di (tertiary phosphine

May 9, 1979 - Contribution from the Department of Chemistry, Eastern Illinois University,. Charleston, Illinois 61920, and the Life Science Division, ...
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Journal of the American Chemical Society / 101:lO / M a y 9, 1979

Controlling the Number of Metal Sites to Which a Di( tertiary phosphine) Coordinates in Group 6 Metal Carbonyls’ R. L. Keiter,*2a Y. Y. Sun,za J. W. Brodack,2a and L. W. Cary2b Contribution from the Department of Chemistry, Eastern Illinois Unicersity, Charleston, Illinois 61920, and the Life Science Dicision, Stanford Research Institute, Menlo Park, California 94025. Receiced September 13, I978

Abstract: Reactions of (OC)sWPPh2CH=CH2 with PPh2H under free-radical or base-catalyzed conditions yield ( 0 C ) y WPPh2CH2CH2PPh2. The reaction of (OC)sWPPh2H with PPh2CH=CH2 under free-radical conditions also gives this product, but in the presence of base only the chelated product, (OC)4W(PPh2CH2CH2PPh2), is formed. The chelation occurs because the intermediate (OC)5WPPh2- loses C O easily in the presence of PPh2CH=CH2 to form (OC)4W(PPh2CH=CH2)(Ph2P)-, which subsequently undergoes cyclization. Reactions of trans-(OC)4M(PPh2CH=CH2)2 ( M = Cr, Mo, W) with 2 mol of PPh2H, under base-catalyzed conditions, yield trans-(OC)4M(PPh2CH2CH2PPh2)2,complexes in which two PPh2CH2CH2PPh2 molecules are coordinated as monodentate ligands. When these reactions are carried out under free-radical conditions, isomerization and cyclization result to give (OC)4M[PPh2CH2CH2CH(PPh2)CH2PPh2]. The tridentate molecule is present as a bidentate ligand and forms a six-membered ring. The reaction of cis-(OC)4W(PPh2H)2 with Ph2PCH=CH2 i n the presence of base yields (OC)4W(PPh2CH2CH2PPh2) while in the presence of a free radical it gives trans-(OC)4W(PPhzCHzCH2PPh2)2. The isomerization which occurs in the latter reaction appears to proceed intramolecularly. All complexes are characterized by 3’P N M R . The reactions provide a method of synthesizing complexes in which diand tri(tertiary phosphines) are not fully coordinated

The inertness to substitution of group 6 metal carbonyls PPh2CH=CH2 to form the anionic (OC)5suggests the possibility of synthesizing many complexes of W PPh2CH2cHPPh2. However, we have evidence which these metals in which Ph2PCHzCHlPPh2 serves as a monosuggests that this species is not an intermediate. It appears that, dentate ligand. Complexes of this type are somewhat rare when PPh2- is in the coordination sphere, it labilizes a carbonyl principally because conditions normally employed for comgroup. This is not without precedent since it is well-known that plexation favor the formation of chelated products. In this work group 6 anionic complexes, (OC)5MX- (X = halide), readily we have explored catalytic methods of preparing (OC)5give up CO in the presence of tertiary phosphines.’ ExperiW PPh2CHlCH2PPh2 and ( O C ) ~ M ( P P ~ ~ C H ~ C H(M ~ P P ~mental ~ ) Z evidence for the displacement of CO from ( 0 C ) s WPPh2- is provided by isolation of cis-(OC)4W(PPh3)= Cr, Mo, W ) by addition of PPh2H to coordinated diphenylvinylphosphine and by addition of coordinated diphenyl(Ph2PH) from the reaction of (OC)5WPPh2H with PPh3 in the presence of base.8 This complex, unlike its PPh2CH=CH2 phosphine to PPh*CH=CH2. analogue, reacts no further. W e propose the mechanism in Scheme I to account for the observed chelation. Support for Results and Discussion the cyclization step is found in the work of Treichel and Wong, The reaction of (OC)sWPPh2CH=CH2 with PPh2H in who have shown that C~S-(OC)~C~(PP~~CH=CH~)(PP~~H) T H F in the presence of potassium tert-butoxide leads to the synthesized by an alternate route, cyclizes in the presence of formation of (OC) jWPPh2CH2CH2PPh2 in good yield. The base.9 mechanism for this reaction undoubtedly parallels that proThe reactions of (OC)sWPPh2CH=CH2 with PPh2H and posed previously for the base-catalyzed addition of secondary of (OC)SWPPh2H with PPh2CH=CH2 in the presence of phosphines to vinylpho~phines.~.~ It is clear that the carbonyl potassium tert-butoxide and AIBN are summarized in Table groups of the complex are less susceptible to attack by the I. nucleophile Ph2P- than is the vinyl group of the coordinated For a complex to contain two Ph2PCHzCH2PPh2 monopho~phine.~ dentate ligands is rare. King and Saran have isolated ($The addition reaction was found to be equally productive C ~ H S ) M O ( P P ~ ~ C H ~ C H ~ P P ~ ~ ) ~ [ C =from C ( CaN ) ~ ] ~ C I when the base catalyst was replaced by the free-radical catasubstitution reaction.I0 However, most attempts to prepare lyst, 2,2’-azobisisobutyronitrile(AIBN), which is consistent Scheme I with the mechanism proposed for the free-radical addition of secondary phosphines to vinylph~sphines.~ (OC),WPPh2H + -0Bu-t (OCXWPPh,HOBU-t To determine if the reaction proceeds equally well when PhzPH is coordinated we examined the free radical catalyzed (OC),WPPh2Ph,PCH=CH, addition of (OC)jWPPh2H to PPh*CH=CH2. The reaction PPh Lproceeds very rapidly at 80 OC as evidenced by immediate co cis.(oc)4w solidification of the reaction mixture. \ To our surprise we discovered that (OC)5WPPh2H does not PPh2CH=CH2 react with PPh2CH=CH2 in the presence of potassium tertPPh i-CH2 butoxide to give ( O C ) S W P P ~ ~ C H ~ C HFrom ~ P P this ~ ~ .reaction only chelated product, (OC)4W(PPh2CH2CH2PPh2), (OC),W I was isolated. A mechanism to account for this reaction cannot \PPhLMCHinvolve (OC)5WPPh2CH2CH2PPh2 since chelation does not occur when this compound is heated in refluxing THF in the presence of potassium tert-butoxide. One might expect (OC)5WPPh2-, which undoubtedly forms, to interact with

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Di(tertiary phosphine) Coordinates in Group 6 Metal Carbonyls

Table I. Preparative Data for ( O C ) S W P P ~ ~ C H ~ C H ~ P P ~ ~ Scheme I1

yield, catalyst

reactants Ph2PH (OC)sWPPh2CH=CH2 ( O C ) S W P P ~ ~ C H = C H ~Ph2PH Ph2PCH=CH2 (OC)5W PPh2H Ph*PCH=CH2 (0C)sW PPh2H

KOBU-t AIBN KOBU-t AIBN

%

72 82 0 75

trans-(OC),M

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PPh&H=CH,

‘PPh,CH= -t

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.PPb

CH2

cis-(OC),M

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PPh2CHCH,PPh2

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PPb,CH=CH,

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PPh,CHCH*PPh, / \ complexes of this type by substitution lead predictably to (OC),M chelation. ‘PPh,CH The addition of PPh2H to trans-(OC)4M(Ph2PCH--LH2)2 (M = W, Mo, Cr) to give trans-(OC)4M( PPh2CH2CH2PPh2)2 was easily accomplished with catalytic potassium tert-butoxide.’ I Our attempts to convert cis(OC)dW(PPh2H)2 into C ~ ~ - ( O C ) ~ W ( P P ~ ~ C H ~ C H ~ P ~ Z ) ~ were unsuccessful. The base-catalyzed reaction of cisI,M= W (OC)4W(PPh2H)2 with PPh2CH=CH2 gave only the che11, M = Cr lated product (OC)4W(PPh2CH2CH2PPh2). This can be explained by assuming that the Ph2P- in the coordination sphere 111, M = Mo of [(OC)4W(PPh2H)(Ph2P)]- labilizes the other ligands as pairs of tungsten complexes also show the trans isomer to have was observed for [(OC)sWPPh2]-. When the free-radical a larger 2 J p p than the cis.15 approach was applied to the same reaction, addition across the The reaction of trans-(OC)4W(PPh2CH=CH2)2 with 2 double bond took place but was accompanied by isomerization mol of Ph2PH under free-radical conditions does not produce to give the trans derivative: trans-(OC)4W(PPh2CH2CH2PPh2)2but rather an air-sensitive cyclic product (I) (Scheme 11). T h e absence of any cis-(OC)4W(PPh2H)2 2PPh2CH=CH2 product with PPh2H in the coordination sphere and the absence AIBN trans- (OC),W( P P ~ ~ C H Z C H ~ P of P ~chelated ~ ) ~ PPh2CH2CH2PPh2 suggests again that the isomerization proceeds by an intramolecular route. N o evidence for chelated product was found. Some chelation The structure of I was established with 3 ’ P N M R . The would be expected if this isomerization proceeds by a dissocomplex contains three chemically nonequivalent phosphorus ciative mechanism unless dissociation followed by rearatoms and the proton-decoupled I P spectrum represents an rangement and association is faster than dissociation followed A M X spin system with three phosphorus-phosphorus coupling by chelation. An intramolecular isomerization may be operconstants, 2Jpp, 3Jpp, and 5 J p p . The chemical shift a t -20 ppm ative here, precedent for which is found in the case of transcan easily be assigned to phosphorus atom 3, which is not (OC)4W(CS)(13CO), which has been shown to isomerize to coordinated to the metal. The observed chemical shift is very cis intramolecuIarly.12 close to the calculated value of -21 ppm which is obtained The ) ‘ P N M R spectra of (OC)4M(PPh2CH2CH2PPh2)2 from the sum of the respective group contributions for the two establish the presence of two PPh2CH2CH2PPh2 groups phenyl groups (-6 ppm) and an “isobutyl” group (-15 coordinated as monodentate ligands. The free phosphine is pprn).l6 The chemical shifts +17.7 and +4.0 pprn can be asfound upfield from 85% H3P04 a t about -12 pprn while the signed to phosphorus atoms 1 and 2, respectively. Grim and coordinated phosphorus is substantially downfield from the co-workers have shown that the chemical shifts of coordinated reference. The observed chemical shifts are consistent with phosphorus atoms are much farther downfield for five-memthose reported for other monoligate monometallic sysbered rings than for six-membered rings. For (0C)dt e m ~ . ~ In . ’the ~ ~case ’ ~ of trans-(OC)4W(PPh2CH2CH2PPh2)2 W(PPh2CH2CH2PPh2) a chemical shift of +40 ppm was coordination of one phosphorus for each ligand is confirmed recorded, whereas for (OC)4W(PPh2CH2CH2CH2PPh2) a by the presence of I8)W satellites. value of 0 ppm was found. The structure around the phosThe 3 1 Pspectra are of special interest because they provide phorus atom 2 in I resembles the structure around each phosdirect measurement of phosphorus-phosphorus coupling phorus atom in Grim’s six-membered ring and supports our through a metal atom. The proton-decoupled phosphorus assignment. Tungsten-phosphorus coupling constants for I spectra may be classified as AA’XX’. Each spectrum has two were found to be 221.1 (Jwpi) and 226.5 (Jwpz) Hz. These doublets of separation N(3Jpp 5Jpp), one in the X and one values do not clearly distinguish between the two possible ring in the A part, which represent half the total intensity. A pair structures since reported coupling constants for the five- and of inner lines and a pair of outer lines in each part account for six-membered rings are 231 and 222 Hz, respectively.‘’ The the other half of the intensity. The separation between an outer most convincing evidence in support of the six-membered ring line and the first inner line is * J p p . While 2 J p p has been deis provided by the value of 2 J p p (21.5 Hz). It has been proposed that the observed phosphorus-phosphorus coupling constant termined for a variety of cis and trans isomers of group 6 for a chelated complex will be the sum of two contribucomplexes in which the phosphorus ligands are chemically tions-coupling through the ligand backbone and coupling equivalent, few if any of these studies involve ligands with through the metal.’* Based on data from a number of tungsten phenyl substituents. Absolute values of 2 J p p for the trans complexes, 2 J p p values of 22 Hz for six-membered rings and complexes of chromium, molybdenum, and tungsten are 26.0, 4 Hz for five-membered rings have been assigned. For six55.8, and 54.3 Hz, respectively. The much smaller 2 J p p value membered rings it is assumed that coupling through the for chromium is characteristic of other reported trans combackbone is zero so the full 22 Hz is attributed to coupling plexes as well. Spectral data for cis-(OC)dthrough the metal. The argument appears valid in light of the W(PPh2CH2CH2PPh2)2, which appeared as a minor impurity C H that ~ P P2 J~p ~ p ) was ~ ,found to be 21.3 Hz in c i ~ - ( o C ) ~ in a sample of impure ~ ~ u ~ s - ( O C ) ~ W ( P P ~ ~ C H ~fact W(PPh2CH2CH2PPh2)2 (no possible backbone contribution) revealed a 2 Jvalue ~ of ~21.3 Hz. Other reported cis and trans

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Journal of the American Chemical Society 101:lO 1May 9,1979

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and 21.5 H z in our six-membered ring system. Furthermore, (OC)4W(PPhzH)2 were prepared from the hexacarbonyls and the appropriate phosphine in diglyme by methods described previ2 Jvalues ~ ~ for the cyclic chromium and molybdenum comously.25 plexes I1 and I11 are 39 and 28 Hz, respectively, which is trans-(OC)4Cr(PPh~CH=CHz)z (42%): mp 145-147 OC dec; IR consistent with the values of 41 and 28 H z predicted for six1891 (E"), 1944 (Big), and 201 1 ( A I & cm-'; 31PN M R 6 64.2. membered rings. Predicted values for five-membered rings for Anal. Calcd for C32H2604PCr: C, 65.31; H, 4.45; P, 10.53. Found: chromium and molybdenum complexes are 12 and 5 Hz, reC, 65.14; H , 4.47; P, 9.88. spectively. Constants for the long-range coupling between frans-(OC)4Mo(PPh2CH=CH2)2(46%): mp 148-150 "C; IR phosphorus atoms 2 and 3 are 3.6,3.7,and 4.9 H z for the 1897 (E"), 1958 (Big), and 2026 (Alg) cm-I; 3 1 PN M R 6 41.8. tungsten, molybdenum, and chromium complexes, respecAnal. Calcd for C32H2604PMo: C, 60.77; H, 4.14; P, 9.79. Found: tively. Phosphorus-phosphorus coupling over five bonds in C , 60.68; H, 4.18; P, 9.88. trans-(OC)4W(PPh2CH=CH2)2(57%): mp 147-149 OC; 1R 1890 systems in which multiple bonding is not present is generally , 2021 (AI,) cm-l; 31PN M R 6 17.9 (JWP = (E"), 1946 ( B I ~ )and not 0 b ~ e r v e d . I ~ 281.1 Hz). Air oxidation of I yields the expected phosphine oxide. The Anal. Calcd for C32H2604PW: C, 53.56; H , 3.64; P, 8.60. Found: 3 1 Pchemical shift for phosphorus atom 3, which appeared a t C, 53,53; H, 3.78; P, 8.75. -20.1 ppm for I, appears for the oxide at +32.2 ppm, consiscis-(OC)4W(PPh2H)2 (38%): mp 88-90 'C; 2020 AI(^)), 1917 tent with chemical shifts for reported phosphine oxides.*O As ( A I ( ] ) ) and , 1903 (B1 B2) cm-l; 3 1 P N M R6 -2.8 (Jwp = 224.1, would be expected, the chemical shifts and coupling constants J P H = 342 Hz). associated with the two coordinated phosphorus atoms change Reactions of (OC)sWPhtCH=CHzwith PPhzH. A. Base Catalyzed. little upon oxide formation. A solution of (OC)5WPPh2CH=CHz (0.006 mol) in T H F (40 mL) was added dropwise to a refluxing solution of PPh2H (0.007 mol) and The reaction of trans-(OC)4Cr(PPh2CH=CH2)2with potassium tert-butoxide (0.2 g) in T H F (100 mL) over a I-h period. PPh2H in the presence of AIBN gave a 2:l mixture of I1 and ~ ~ u ~ s - ( O C ) ~ C ~ ( P P ~as ~ shown C H ~ by C H31P ~ NPMPR~. ~ ) After ~ an additional 30 min of reflux, the solution was cooled and the solvent was removed with a rotary evaporator. The oily residue was The reaction of trans-(OC)4Mo(Ph2PCH=CH2)2 with dissolved in CH2C12 ( I O mL) and H 2 0 ( I O mL). Addition of 20 mL PPh2H i n the presence of A I B N gave 111, ( 0 C ) p of CH30H to the organic layer gave, after 12 h at 5 "C, white crystals Mo( PPh2CH2CH2PPh2), and free Ph2PCH2CH2PPh2 in of (OC)sWPPhzCH2CH2PPh2. The product (72%) was recrystallized approximately equal proportions. It appears that transfrom CH2C12 (5 mL) and CH3OH ( I 5 mL). (OC)4Mo( PPh2CH2CH2PPh2)2 is unstable under the reaction B. Free Radical Catalyzed. A mixture of (OC)5WPPh2CH=CH2 conditions with respect to diphos expulsion and chelation. (0.006 mol), PPh2H (0.007 mol), and AIBN (0.1 g) was heated Chemical investigations of polydentate phosphorus ligands without solvent at 65 " C for 12 h. Excess PPh2H was removed by heating under vacuum for 2 h. The oily product was crystallized as quite naturally have been focused on their chelating properties. describedabove (82%), mp 122 " C (lit.I3 mp 116-1 17 "C). IdentifiThere are, however, interesting synthetic possibilities for cation was by 3'P NMR.13 complexes in which a ligand is not fully coordinated. For exReactions of (0C)SWPPhzH with PPh2CH=CHz. A. Base Cataample, the availability of these complexes as starting materials lyzed. Diphenylvinylphosphine (0.002 mol) in T H F (25 mL) was greatly enhances the ease with which two or more different added to a refluxing solution of (OC)5WPPh2H (0.002 mol) and metal atoms can be introduced into a single coordination potassium tert-butoxide (0.2 g) in T H F (50 mL) over a I-h period. compound.20s2' Further, complexes in which a ligand is not After removal of solvent, the crude product was crystallized from fully coordinated contain a reactive phosphorus site upon which CHzCl2 (10 mL) and CH3OH (20 mL). The chelated product, organic reactions can be carried out.22 (OC)4W(PPh2CH2CH2PPh2) (52%), was identified by 3IP

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Experimental Section Physical Measurements. 3 1 PN M R spectra were recorded at 40.5 MHz and 13C spectra at 25.2 MHz on a Varian XL-100 N M R spectrometer equipped with Fourier transform and a pulsed deuterium lock. The I C - I H and 31P-1H couplings were eliminated using broad-band I H noise-modulated decoupling. Phosphoric acid (85%) in a 1.0-mm capillary was used as an external reference for the 3 1 P N M R spectra, and Me& was used as the internal reference for the I3C NMR spectra. CDCI3 was used for solvent and lock. 3 1 PN M R chemical shifts are reported with positive values downfield from the reference. Infrared spectra in the carbonyl region were recorded with a Perkin-Elmer 337 infrared spectrometer and expanded with an E-H Sargent recorder. The data, obtained from chloroform solutions, are considered accurate to f 2 cm-'. Microanalyses and molecular weights were performed by Galbraith Laboratories, Knoxville, Tenn. Materials. Diphenylvinylphosphine, diphenylphosphine, and the mctal carbonyls were purchased from Pressure Chemical Co. and used without further purification. All reactions were carried out under a nitrogen atmosphere. (OC)5WPPh2CH=CH2 (79%) and (OC)sWPPh2H (61%) were prepared by the indirect method of Strohmeier.23 (OC)sWPPh2CH=CH2: mp 64-65 "C; 1R 1984 ( B l ) , 2073 ( A I ( * ) ) ,and 1940 ( E A I ( ] ) )cm-I; 3 1 PN M R 6 11.4 (Jwp = 239.4

Hz).

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Anal. Calcd for ClgH1305PW: C, 42.57; H, 2.44; P, 5.78. Found: C, 42.69; H, 2.38; P, 5.69. (OC)sWPPh2H: mp 91-93 "C (lit.24mp 90-92 "C); IR 1985 (B,), 2077 and 1947 (E Al(l)) cm-]; 3 1 PN M R 6 -13.7 (Jwp = 229.6, JPH= 344.9 Hz). fruns-(OC)4M(PPh2CH=CH2)2 ( M = Cr, Mo, W) and cis-

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NMR.17 B. Free Radical Catalyzed. A mixture of (OC)5WPPh2H (0.004 mol), PPh2CH=CH2 (0.005 mol), and Albn )0.1 g) was heated to 75 "C, whereupon immediate solidification of the reaction mixture occurred. Recrystallization a s described above gave (OC)5WPPh2CH2Ch2PPh2 (75%). Reaction of (0C)sWPPhzH with PPh3. Base Catalyzed. Care was taken to follow a procedure identical with that for the reaction of (OC)SWPPh2H with PPh2CH=CH2. White crystals of cis-(OC)4W(PPh3)(PPhzH) (58%) were obtained: mp 166 " C dec; IR 2024 1903 ( B I ) , and 1889 (B2) cm-l; 3 1 PN M R 6 1920 3.1 (d, J p p = 17.0, Jwp = 229.6 Hz, PPhzH), 24.0 (d, J p p = 17.0, Jwp 230.9 Hz, PPh3). Anal. Calcd for C34H2604P2W: C, 54.86; H, 3.52; P, 8.32. Found: C, 54.82; H , 3.70; P, 8.19. Reactions of trans-(OC)4M(PPh2CH==€H2)~ (M = W, Mo, Cr) with PPh2H. A. Base Catalyzed. To refluxing PPh2H (0.008 mol) and AIBN (0.2 g) in T H F (100 mL), fruns-(OC)4M(PPh2CH=CH2)2 (0.004 mol) was added dropwise over a I-h period. After an additional 30 min of reflux the solution was cooled, filtered, and reduced to an oily mass with a rotary evaporator. The impure product was treated with CH2C12 (15 mL) and H 2 0 (20 mL). Addition of C H 3 0 H (20 mL) to the organic layer gave, after cooling at 5 OC for 12 h, trans(OC)4M( P P ~ z C H ~ C H ~ P P ~ ~ ) ~ . ~~U~~-(OC)~W(PP~~C (56%): H~C mpH151-152 ~ P P ~ OC; ~ ) IR ~ 1888(E,), 1945 (BIg),and2020(Alg)cm-1;31PNMR6wp 18.8(m. AA'XX' pattern, 2 J p p = 54.3, 3 J p p s J p p = 37.6, Jwp = 279.4 Hz), 6p -12.1 (m. AA'XX' pattern, 2 J p p = 54.3, 3 J p p 5 J p p = 37.6 Hz). Anal. Calcd for C56H48P404W: C, 61.55; H, 4.43; P, 1 1.34. Found: C, 61.70; H, 4.30; P, 1 1 . 1 I . cis-(OC)bW( PPh2CH2CH2PPh2)2 was observed as a minor product in the 3 1 P N M R spectrum of impure t r ~ n s - ( O C ) ~ ~ ( P P ~ ~ C H ~ C H ~3IP PN PM ~R Z 6wp ) ~ :12.7 (m, AA'XX' pattern,

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(20 m L ) was added to PPh2CH=CH2 (0.005 mol) and potassium = 21.3, 3Jpp 'Jpp = 36.7 Hz, Jwp unobserved), 6p - 12.6 (m. tert-butoxide (0.2 g) i n THF (100 mL). A f t e r refluxing for 2 h, the A A ' X X ' pattern, 2 J p p = 21.3, ) J p p 5 J p p = 36.7 Hz). ~ ~ u ~ ~ - ( O C ) ~ M O ( P P ~ (28%): ~ C H ~m C p H 134~ P136 P~ "C;~ ) ~ solvent was removed and the impure product was dissolved i n CHzCl2 ( I5 m L ) and H20 ( I O mL). Addition o f CH3OH (20 m L ) to the orI R 1900 (E"), 1945 (Big), and 2020 (Alg) cm-'; ) ' P N M R 6Mop43.1 ganic layer gave (OC)4W(PPh2CH2CH2PPh2) (63%). Identification (m. A A ' X X ' pattern, 2Jpp = 45.7, 3 J p p 'Jpp = 36.6 Hz), 6p - 12.6 was as previously described. (m, AA'XX' pattern, 2Jpp = 45.7, 3Jpp 5 J p p = 36.6 Hz). B. Free Radical Catalyzed. A mixture o f cis-(OC)4W(PPh2H)z Anal. Calcd for C S ~ H ~ ~ P ~ O C, ~66.94; M O : H, 4.81; P, 12.33. (0.002 mol), PPh2CH=CH2 (0.004 mol), and A I B N (0.1 g) was Found: C, 66.69; H, 4.60; P, 12.01. heated at 75 "C for 24 h. Unreacted PPh2CH=CH2 was removed by ~ ~ U ~ S - ( O C ) ~ C ~ ( P P ~ (46%): ~ C H ~mCp H 147-149 ~ P P ~"C;~ I)R~ high vacuum and tr~ns-(0c)~w(PPh~CH~CH~PPh~)~ (43%) was 1886 (E"), 1942 (Big), and 2009 (Alg) cm-'; 3 1 PNMR 6crp 66.0 (m, purified and identified as previously described. A A ' X X ' pattern, 2Jpp = 26.0, 3 J p p 5 J p p = 35.3 Hz), bp - 12.0 (m, AA'XX' pattern, 2 J p p = 26.0, 3 J p p 5Jpp = 35.3 Hz). Acknowledgment is made to the donors of the Petroleum Anal. Calcd for C56H48P404Cr: C, 70.00; H, 5.03; P, 12.89. Found: Research Fund, administered by the American Chemical C, 69.72; H, 4.88; P, 12.41. Society, for the partial support of this research. B. Free Radical Catalyzed. A m i x t u r e o f trans-(OC)dM(PPhzCH=CH2)2 (0.0025 mol), PPh2H (0.005 mol), and A I B N (0.1 g) was heated to 75 "C for 24 h. Unreacted PPh2H was removed under high vacuum at 65 OC for 2 h. References and Notes (OC)4W[P2Ph2CH2CH2CH(PIPh2)CH2P3Ph2](l, 65%) was (1) Preliminary communication: R. L. Keiter, R. D. Borger, J. J. Hamerski, S. obtained by eluting the crude product with 4:l petroleum ether (35-60 J. Garbis, and G. S.Leotsakos, J. Am. Chem. SOC., 99,5224 (1977). OC)/ethyl acetate f r o m a silica gel column and recrystallizing from (2)(a) Eastern Illinois University: (b) Stanford Research Institute. I: I CH2C12/CH3OH: m p 121- I 2 3 "C; m o l w t (CHC13) 884, calcd (3)S. 0. Grim, J. Del Gaudio, R. P. Moienda, C. A. Tolman, and J. P. Jesson, B2) c m - ] ; 3 1 P 907; I R 2013 1918 (AI(])), and 1888 ( B I J. Am. Chem. SOC., 96,3416(1974). (4)R. B. King, Acc. Chem. Res., 5, 177 (1972);R. B. King and J. C. Cloyd, Jr., N M R 6 p l 17.1 (dd,2Jpp= 21.5,3Jpp=9.6,Jwp= 221.1 Hz),6p24.0 J. Am. Chem. Soc., 97,46,53(1975). (dd, 'Jpp = 21.5, 'Jpp = 3.6, J w p = 226.5 Hz), 6p3 -20.1 (dd, 3Jpp (5) The susceptibility of a metal carbonyl group to attack by Me2P- has been = 9.6, 'Jpp = 3.6 Hz); I 3 C NMR 6 34.8 (dd, Jpc = 17.0, 13.3 Hz), demonstrated: E. 0. Fischer, F. R. Kreissel, C. G. Kreiter, and E. W. Mei30.8 (dd,Jpc = 16.2,4.5 Hz), 31.2 (d,Jpc = 23.5 Hz),25.9 (dd,Jpc neke, Chem. Ber., 105,2558(1972). (6)D. L. DuBois, W. H. Myers, and D. W. Meek, J. Chem. SOC.,Dalton Trans., = 13.8, 6.1 Hz). 1011 (1975):D. W. Meek, D. L. DuBois, and J. Tiethof, Adv. Chem. Ser., Anal. Calcd for C44H37P304W: C, 58.30; H, 4.1 I ; P, 10.25. Found: No. 150,335 (1976). C, 57.85; H,4.02; P, 9.81. (7)A. D. Allen and P. F. Barrett, Can. J. Chem., 46, 1649,1655 (1968). Increasing the concentration o f ethyl acetate to 50% i n the eluting (8)This reaction appears to be an excellent method of synthesizing tetracarbonyl complexes of tungsten which contain both a secondary and a solvent allowed the collection of (OC)4W[ P2Ph2CH2CH2CHtertiary phosphine. We are presently exploring the ramifications of the (P1Ph2)CH2P3(0)Ph2] (8%): mp 125-127 "C; I R 2016 (AI(2)), 1920 reaction. (AI(!)), and 1890 (B1 B2) cm-I; 3 1 PN M R 6pl 18.2 (dd, 2Jpp= (9)P. M. Treichei and R. Wong, J. Organomet. Chem., in press. 21.8, 3Jpp = 30.2, Jwp = 223.5 Hz), 6p2 2.3 (d, 'Jpp = 21.8, J w p = (10) R. B. King and M. S. Saran, J. Am. Chem. SOC., 95, 1817 (1973). (1 1) P. M. Treichel and R. Wong have synthesized (OC)&r(PPh2CH2CH2PPh2)2 225.6 Hz), 6p3 32.2 (d, 3 J p p = 30.2 Hz); I3CN M R 6 32.9 (dd, Jpc independently: private communication. = 16.1,4.3 Hz), 30.6 (d, Jpc = 63.9 Hz), 30.3 (d, Jpc = 24.3 Hz), (12)B. D. Dombek and R . J. Angelici, J. Am. Chem. SOC.,98,4110 (1976). 25.2 (d, J = 4.40 Hz). (13)R. L. Keiterand D. P. Shah, Inorg. Chem., 11, 191 (1972);R. L. Keiterand L. W. Cary, J. Am. Chem. SOC.,94,9232 (1972). Anal. Calcd for C44H37P305W: C, 57.29; H, 4.04; P, 10.07. Found: R. B. King and J. C. Cloyd, Jr., Inorg. Chem., 14, 1550 (1975). (14) C, 56.95; H, 4.25; P, 9.60. (15)J. G. Verkade, Coord. Chem. Rev., 9, l(l972-1973). (OC)4Mo[P2Ph2CH2CH2CH(P'Ph2)CH2P3Ph2] ( I I I ) , trans(16)S. 0. Grim, W. McFarlane, and E. F. Davidoff, J. Org. Chem., 32, 781 ( O C ) ~ M O ( P P ~ ~ C H ~ C Hand ~ P PPh2PCH2CH2PPh2 ~~)~, were 11967). (17)S . 0. Grim, W. L. Briggs, R. C Barth, C A. Tolman, and J. P. Jesson, lnorg identified as present in approximately equal proportions b y 3 1 PN M R : Chem.. 13. 1095 (1974). 3 1 P N M R(111) 6pl 38.6 (dd, 'Jpp= 28.0,3Jpp= 8.1 Hz),6p224.1 (dd, (18)S.0. Grim,'R. C.B'arth, J. D. Mitchell, and J. Del Gaudio, Inorg. Chem., 16, 'Jpp = 28.0, 'Jpp = 3.70 Hz),6p3 -19.9 (dd, 3Jpp = 8.1, 'Jpp = 3.70 1776 (1977). Hz). (19)E. G. Finer and R. K. Harris, frog. Nucl. Magn. Reson. Spectrosc., 6,61 (1971). (OC)4Cr[P2Ph2CH2CH2CH(P1Ph2)CH2P3Ph2] (11) and trans(20)R. L. Keiter, K. M. Fasig, and L. W. Cary, Inorg. Chem., 14, 201 (1975). (OC)4Cr(PPh2CH2CH2PPh2)2 (2:l mixture) were identified by 3 1 P (21)R. L. Keiter. J. E. Benedik, Jr., and L. W. Cary. Inorg. Nucl. Chem. Len., 13, N M R . 3 1 PNMR (11) 6p' 59.4 (dd, 2Jpp = 39.7, 3Jpp = 6.1 Hz), 6p2 455 (1977). (22)R. L. Keiter and D. Marcovich, Inorg. NucI. Chem. Len., 10, 1099 44.5 (dd, 2Jpp = 39.7, 'Jpp = 4.90 Hz)6p3 -20.0 (dd, 3Jpp = 6.1,'Jpp (1974). = 4.90 Hz). (23)W. Strohmeier and F. Muller, Chem. Ber., 102, 3608 (1969). Reactions of cis-(OC)dW(PPh2H)zwith PPh2CH=CHz. A. Base (24)J. G. Smith and D. T. Thompson, J. Chem. SOC.A, 1694 (1967). Catalyzed. A solution o f cis-(OC)4W(PPh2H)2 (0.0022 mol) i n THF (25)S.0. Grim and D. A. Wheatland, Inorg. Chem., 8, 1716 (1969).

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