Synthesis and chemistry of chelating phosphinite complexes of Group

Organometallics 1989, 8, 2918-2932

Synthesis and Chemistry of Chelating Phosphinite Complexes of Group 6 Metal Carbonyls with Crown Ether and Aza-Crown Ether Characteristics. The Effect of Preferential Lithium Cation Binding by the Product Molecule on the Reactlvfty of Coordinated Carbon Monoxide John Powell,' Michael R. Gregg, Anda Kuksis, Christopher J. May, and Stuart J. Smith Chemistry Department, University of Toronto, Toronto, Ontario, Canada M5S 1A 1 ReceivedMay 10, 1989

Twenty-seven a,@-bis(dipheny1phosphinite)ligands, prepared from the reaction of 2 equiv of Ph2PCl with the appropriate a,@-diolin the presence of Et3N, react with M(C0)4(norbornadiene)(M = Cr, Mo, W) under high dilution conditions to give metalla-crown and metalla-aza-crown ether tetracarbonyl complexes. Within the series of complexes ~ ~ ~ - M O ( C O ) ~ ( P ~ ~ P O C H ~ ( C H ~ ~the C H 16C5 ~ ) ,(n , C=H ~ O P P ~ ~ ) 3) system will complex Li+ but not Na+ and the 19C6 (n = 4) system will complex Li+ and Na+ but not K+, while the 10C3 (n = 1)and 13C4 (n = 2) systems do not readily complex Li+. Addition of MeLi and PhLi to these group 6 metal carbonyl-crown ether systems results in the formation of the isolable acylate/benzoylate complexes "~~c-M(CO)~(RCOL~)P~]" for llC3, 12C3, 13C4, and 14C4 ring systems while other ring sizes and complexes such as cis-Mo(C0)4(Ph2PO(CH2),,0PPh2) (n = 3, 5) and ~is-Mo(C0)~(PPh20Me)zdo not react with RLi reagents. Equilibrium studies of the reaction "M(C0)4P2+ RLi M(CO),(RCOLi)P," indicate that the features favoring Li+ binding and product stabilization me (i) a ligand should be one donor atom short of providing Li+ with a "full" coordination sphere, (ii) 12-14 atom metalla-crown ether rings, (iii) the ligand must accommodate the stereochemical requirements of the bridging M(RC=O)-Li+ unit, and (iv) the crown ether donor atoms should be as basic as possible (tertiary N > 0, and PhzP-0 >>> Ph,P-NMe]. Kinetic studies of the rate of the reaction of "[M(CO),(PhCOLi)P2]" systems with HzOin THF, to give "M(C0)4P2n,LiOH, and benzene, provide information ( k d data) regarding the relative rate of Li+ decomplexation. 12C3 benzoylate complexes and Mo(CO),(PhCOLi) react with H20in THF to give the starting carbonyl complex, LiOH, and benzene by a process that is first order in both [benzoylate complex] and [H20],while the reaction of 13C4 and 14C4 benzoylates with H20in THF gives rise to a rate law that is first order in [benzoylate] and second order in [HzO]. Equilibrium constant data and the kd data indicate that 13C4 and 14C4 benzoylates are the most stable. The complexes ~~c-M(CO)~(RCOL~)(P~~POCH~(CH~OCH~)~CH~OPP~~) (i) react with Me30+BF4or MeS03F to give the (ii) react with Me3SiC1 carbene complexes fac-M(C0)3(C(OMe)R)(Ph2POCH2(CH20CH2)2CH20PPhz), followed by HzO/MeOH hydrolysis to give the hydroxycarbene fac-M(CO)3(C(OH)R](Ph2POCH2(CH20CHz)2CH20PPh2J, and (iii) react with HX to give [M(C0)3X(Ph2POCH2(CH20CH2)2CH20PPh2]]-Li+ (X = C1. Br). This latter comDound reacts with silver salts in the Dresence of added lieand to eive L = P(OMe),, {BuNC). Y

Introduction Ditopic ligands that combine a subunit containing a "soft" binding site with one bearing a "hard" site may, subject to the stereochemical requirements of the ligand, the coordination requirements of the metals, and the Lewis acidity and/or redox properties of the metal centers involved, give rise to heterodinuclear complexes with unusual properties.'-14 A simple approach to the synthesis of (1) (a) Lehn, J. M. In Frontiers of Science (IUPAC);Laidler, K. J., Ed.; Pergamon: New York, 1982; p 265; (b) Lehn, J. M. Pure Appl. Chem. 1980,52, 2441. (2) Fernuson. G.: Matthes. K. E.: Parker, D. J . Chem. SOC.,Chem. Comkun.-1987,' 1350. (3) Carroy, A.; Lehn, J. M. J. Chem. SOC.,Chem. Common. 1986,1232. (4) Boyce, B. A.; Carroy, A.; Lehn, J. M.; Parker, D. J. Chem. SOC., Chem. Commun. 1984, 1546. (5) Lehn, J. M.; Parker, D. J. Chem. SOC.,Dalton Trans. 1985, 1517. (6) Parker, D. J. Chem. SOC.Chem. Commun. 1986, 1129. (7) Powell, J.; May, C. J. J. Am. Chem. SOC.1982, 104, 2636. (8) Kraihanzel, C. S.; Sinu, E.; Gray, M. G. J. Am. Chem. SOC.1981, 103, 960. (9) Wrobelski, D. A.; Rauchfuss, T. B. J . Am. Chem. SOC.1982,104, 2314. (10)McLain, S. J. J. Am. Chem. SOC.1983, 105, 6355. (11) Powell, J.; Kuksis, A.; May, C. J.; Nyburg, S. C.; Smith, S. J. J . Am. Chem. SOC.1981,103, 5941. (12) Powell, J.; Gregg, M. R.; Kuksis, A.; Meindl, P.J. Am. Chem. SOC. 1983, 105, 1064. (13) Powell, J.; Ng, K. S.; Ng, W. W.; Nyburg, S. C. J . Organomet. Chem. 1983,243, C1.

Y

heterodinuclear complexes containing low oxidation state transition metals and cations of groups 1A and 2A involves the synthesis of hybrid ligands in which a crown ether or cryptand functionality is combined with one or more Pdonor g r o ~ p s . ~ J Some @ ~ ~ early examples of transitionmetal complexes containing crown ether functionalities were reported in a series of papers by Shaw et al.'"" and include complexes of the type 1 and 2. Of prime interest

with respect to the chemistry of heterobimetallic complexes derived from hybrid P-donor crown ether ligands is the possible effect(s) that the presence of a proximal class 1A/2A cation may have on the reactivity of ligands coor(14) Powell, J.; Nyburg, S. C.; Smith, S. J. Znorg. Chim. Acta 1983, 76, 1.75. -. -.

(15) Hyde, E. M.; Shaw, B. L.; Shepherd, I. J. Chem. SOC.,Dalton Trans. 1978, 1696. (16) Shaw, B. L.; Shepherd, I. J. Chem. SOC.,Dalton Trans. 1979, 1634. (17) Odell, K. J.; Hyde, E. M.; Shaw, B. L.; Shepherd, I. J. Organomet. Chem. 1979, 168, 103.

0 2 ~ 6 - ~ 3 3 3 / ~ 9 / ~ 3 a ~ - z 9 i ~ ~ aoi .1989 5 0 / 0American Chemical Society

Organometallics, Vol. 8, No. 12, 1989 2919

Phosphinite Complexes of Group 6 Metal Carbonyls dinated to the transition metal.’*14 For example, it is well-known that coordinated carbon monoxide may be activated with respect to alkyl/aryl migration (Le. nucleophilic addition) by formation of an adduct between a Lewis acid and a carbonyl oxygen in L,M(R)(CO) and/or by stabilization of the acyl products L,M(RCO-A) (e.g. A = Al13r3, Cp,Zr, Li+).lgM For group 1A cations Li+ has the most pronounced effect. Thus, for example, Collman et al. showed that the rate of the ligand-induced alkyl migration reaction in M+[FeR(C0)4]-to give M+[Fe(C(O)R)(CO),L]- (eq 1)is both cation and solvent sensitive M’[FeR(COh]-+

PR3 --+

M+[Fe{C(O)R} (C0)3(PR3)](eq. 1)

with the rate for the Li+ salt (capable of tight ion pairing; i.e. Li+.-OC interactions) being > 2 X lo3 that for the [Ph3P=N=PPh3]+ salt.lg On the basis of infrared studies of the benzoylate product molecule Li+[Fe(C(O)Ph)(C0),(PPh3)]-, Darensbourg et al. proposed the interaction between the benzoyl (acyl) and terminal carbonyl oxygens to be as shown (Figure l).mA hybrid P-donor crown ether ligand with appropriate stereochemical features enabling it to bind to an acyl-bridged “M(RCO)Li+”unit, as represented schematically in Figure 2, should lead to an increased stability of acylate products. On the basis of molecular models it should be possible to devise ligand systems with the requisite stereochemical features that either (i) have a crown ether ring attached to pendant P-donor groups (e.g. complexes 31° and 425), (ii) have the P-donor atom(s) integrated into the crown ether ring (e.g. complex 513),or (iii) by the use of a,w-di-P-donor polyether ligands, have the transition metal incorporated into a crown ether ring as in complex 6 . ” ~ ’ ~However the PA

describe the cis chelation of these ligands to group 6 metal carbonyls to give complexes of the type ~ i s - M ( C 0 ) ~ (Ph2POCH2(CH2ACH2),CHzOPPh2) (A = 0, NMe) etc., assess briefly the crown ether/group 1A complexing properties of these “M(C0)4P2ncomplexes, and report on their selectivity with respect to the addition of RLi to a coordinated carbonyl group to give acylate/benzoylate complexes “fac-M(C0),(RCOLi)P2”(e.g. 6), the stability of which is determined by the ease/degree of “preferential Li+ cation binding”. A complimentary approach to CO activation in metal carbonyls using the amphoteric ligand system Ph2PNRA1R’2has been described by Labinger et a1.26

Results The reaction of the readily available di-, tri-, tetra-, and pentaethylene glycols with 2 molar equiv of diphenylchlorophosphine in the presence of base yielded the a,wbis(dipheny1phosphinite)ligands 7-10 as viscous colorless oils (eq 2). As these compounds were not easily purified,

A/+

HO

10

AA

+

C5H5N P h 2 W 1 0 ],0PPh2+ 2Ph2PCI CH2Ch/Ei20* 0°C 7 n=l 0 n=2 9 n=3

-

pyH’CI(eq. 2 )

10 17.4 -

care was taken to use freshly distilled, dry reagents and the ligands 7-10 were used “as is” subject to satisfactory NMR characterization. Reaction of the ligands 7-10 with a molar equivalent of M(C0)4(norbornadiene)(M = Cr, Mo, W) using high-dilution conditions gave the metallacrown ether complexes M(C0)4(Ph2POCH2(CH20CHJnCH20PPh2) [ll ( n = l), 25 ( n = 2), 31 ( n = 3), and 32 ( n = 4)] (eq 3). Reactions were run in CH,C12

II n=i

25. n.2

(eq.3)

31 n = 3 32 17.4

donor crown ether ligands of the type shown in complex 1 have too great a separation between the crown ether and P-donor ligating groups to be able to stabilize a “M(RCO)-.Li+” interaction. Complexes 3,5, and 6 have been the subject of preliminary comm~nications.’*’~ In this paper we report the synthesis of a range of a,w-bis(diphenylphosphinito)polyether ligands and amino analogues {e.g. Ph2POCH2(CH2ACH,),CHzOPPhz (A = 0, NMe; n = 1-4), Ph2PO(CH,)3A(CH2)30PPh,(A = 0, NMe), etc.), (18)Butts, S. B.; Strauss, S. H.; Holt, E. M.; Stimson, R. E.; Alcock, N. W.: Shriver. D. F. J. Am. Chem. SOC.1980.102.5093 and references therein. ....~ .~~~ (19) Collman, J. P.; Finke, R. G.; Cawse, J. N.; Brauman, J. I. J. Am. Chem. SOC.1978,100, 4766. (20) Darensbourg, M. Y.; Baros, H. L. C. Inorg. Chem. 1979,18,3286 and referenceslherein. (21) Demitras, G. C.; Muetterties, E. L. J . Am. Chem. SOC.1977,99, 2796. (22) Muetterties, E. L.; Stein, J. Chem. Rev. 1979, 79, 479. (23) Longato, B.; Norton, J. R.; Huffman, J. C.; Marsella, J. A.; Caulton, K. G. J . Am. Chem. SOC. 1981, 103, 209. (24) Butts, S. B.; Richmond, T. G.; Shriver, D. F. Inorg. Chem. 1981, 20, 278. (25) Powell, J.; Ng, K. S., manuscript in preparation.

solutions at room temperature for M = Mo and in refluxing benzene solution for M = Cr and W. High-dilution conditions were used to ensure maximization of ring formation relative to the competitive reaction of polymerization. After chromatographic workup the metalla-crown ether complexes were obtained as white (M = Mo, W)or pale yellow (M = Cr) crystalline materials in yields of 2 0 4 % . The full range of metalla-crown ether and metalla-azacrown ether complexes 11-35 were similarly prepared beginning with the appropriate diol precursor of the required bis(dipheny1phosphinite) ligand and following the procedures outlined in eq 2 and 3. Attempts to make the 13C3 complex 38 from the ligand Ph,PO(CH,),O(CH2),0PPh2gave instead the complex Mo(CO)~(P~,PO(CH2),0PPh,) (39a) (eq 4). It is presumed that the rePh2PO[CH2&O(CH,),OPPh2

30 -

+ MO(CO),(NBD)

+

390 -

(26) Labinger, J. A,; Bonfiglio, J. N.; Grimmett, D. L.; Masuo, S. T.; Shearin, E.; Miller, J. S. Organometallics 1983, 2, 733.

2920 Organometallics, Vol. 8, No. 12, 1989

Powell et al.

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Figure 3. The change Ab('%) in the chemical shift of the metalla-crown ether carbon nuclei and the a-phenyl carbon nuclei of MO(CO)~(P~~POCH~(CH~OCH~)~CH~OPP~~J (31a) upon addition of LiPFB(0.17 M solution of 31a in CDCl,). action involves the elimination of a molecule of THF which occurs after ligand complexation. The structure of 39a was confirmed by the synthesis of 39a from the ligand Ph2PO(CH2),0PPh2. The complexes M o ( C O ) ~ ( P ~ ~ P O -Figure 4. The 31P(1H] NMR spectrum of the benzoylate complex , (CH2)50PPh2](39b) and C ~ S - M O ( C O ) ~ ( P P ~(40) ~ O M ~ )M~o ( C 0) ( P hCOLi) ( P h 2 P 0(CH2)3NCH(CH2CH20PPh2)were prepared for reference purposes. Complexes 11-39 CH2CH2CH2CH2) (52) illustrating the presence of two isomeric were characterized by IR [v(CO) region], lH, 13C('H),and forms and the two probable forms (1)and (2) based on molecular 31P(1H)NMR spectroscopy, elemental analysis, and momodels. lecular weight studies on selected complexes which confirmed the monomeric structures as shown. Selected data Reaction of t h e Metalla-Crown E t h e r Tetrafor "M(C0)4P2"systems are given in Table I. To aid carbonyl Complexes with RLi. In an attempt to prepare subsequent discussion the structural formulas of complexes acylate/benzoylate complexes from the addition of RLi to 11-37 are further labeled to indicate the carbon chains a coordinated CO, complexes 11-37 were reacted with RLi found in the metalla-crown ether. For example the noreagents in either dry THF or benzene. Synthetic reactions tation llC3[2.3(NMe)] indicates the presence of a NMe using the 1OC3[2.2] complex 11, the 16C5 complex 31, the group between the -CH2CH2- and -CH2CH2CH2- chains 19C6 complex 32, the all aza-crown ether system 34, and in the metalla-11-aza-crown-3 complex 15. The complexes complexes 35,39, and 40 were all unsuccessful with starting isolated from the reaction of these "M(CO)4P2nsystems material being recovered on workup. The reaction was not with RLi are given in parentheses under the appropriate promoted by the addition of tetramethylethylenediamine. MeLi or PhLi heading (see structures of 11-39). In contrast the 13C4[2.2.2] complexes 25 reacted rapidly 13C(lH1NMR spectroscopy may be used as a probe to with a range of organolithium reagents to give the acymonitor the interactions of crown ethers with alkali-metal late/benzoylate complexes fac-(CO),(RCOLi)cation^.^'^^* The 13C(lH]NMR spectra of the complexes (Ph2POCH2(CH20CH2),CH20PPh2) [R = Ph (54), Me (66), M(C0)4{Ph2POCH2(CH20CH2)nCH20PPh2J [ll (n = l ) , NEt, (70), N'Pr, (71), p-tolyl (72)] (eq 5). Similar ben25 (n = 2), 31 (n = 3), and 32 ( n = 4)] were recorded in R CDC1, in the presence of various equivalents of LiPF6, NaPF6, or KPFG. A shift in the b(13C)'s for the ring methylene carbons and Ca of the phenyl groups implies significant metalla-crown ether-cation interaction. Figure 3 illustrates the changes in 6(C) for the 16C5[2.2.2.2] 250 540 R = P h complex 31a upon addition of varying amounts of LiPF6. 660 R=Me The results of these qualtitative studies may be summa70 R ' E I z N rized as follows: (i) The 1OC3[2.2] complex 11, the 7I R='PQN 7 2 R z p-tolyl 13C4[2.2.21 complex 25, and cis-MoGO),( PPh20Me) (40) showed no evidence of interactions with MPF6 (Le. were zoylate and acy'ate complexes were successfully synthesunable to solubilize LiPF6 etc. in CDC1,); (ii) the 16C5 ized from the reaction of RLi with complexes 12-30 and complex 31 exhibited 1:l complexationwith LiPF, (Figure with the lariat 10C3 system 33. Rapid formation of these 3) but did not complex NaPF6; (iii) the 19C6 complex 32 acylate/benzoylate products was indicated by an immeexhibited changes in the 13C{lHJNMR consistent with 1:l diate color change from colorless to yellow/orange and the complexation of both Li+ and Na+; and (iv) the lack of a fact that in benzene the acylate/benzoylate product fresharp break in the As(C) vs 3la:LiPF, ratio is indicative quently precipitated from solution within 1min of mixing. of a relatively low stability constant for the metalla-crown Selected spectroscopic and analytical data of the products ether-Li+ complexation. of these RLi reactions, complexes 47-71, are given in Tables I1 and 111. The 12C3, 13C4, and 14C4 complexes 47-59 and 63-72 were reasonably stable and could be re(27) Lehn,J. M.; Sonveaux, E.;Willard, A. K.J. Am. Chem. SOC.1978, crystallized from CH2C12/hexane. The 10C3 and l l C 3 100,4914. acylate and benzoylate products 61-62 and 41-46 decom(28) Shamsipur, M.; Popov, A. I. J . Am. Chem. SOC.1979,101,4051.


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Phosphinite Complexes of Group 6 Metal Carbonyls Table IV. Selected Bond Lengths (A) and Bond Angles (deg) Associated with the Lit Cation Coordination Geometry in Metalla-Crown Ether Lithium Benzoylates (See Figure 5) comdex 548 48 53 60a Li-O(1) Li-0(2) Li-0(3) Li-0(4) or Li-N Li-0(5) ~0(1)Li0(2) ~0(1)Li0(3) LO(l)Li{O(4)or N) LO( l)LiO(5) LO(2)LiO(3) ~0(2)Li{0(4) or N) L0(2)Li0(5) LC(1)0(1)Li

1.84 2.08 2.01 2.20 2.04 103 104 118 110

103 77 79 126

1.95 1.95 2.04

1.85 1.94 1.91 2.03

109 113 110

111

99

110 103

110 104

1.88

...

...

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119

1.92 2.01 2.09 2.23 2.02 101 103 177 100 97

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115

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I2 c 3 [3.3 - 6 - ring ]

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120 131

126

posed fairly rapidly in CH2C12to regenerate the starting tetracarbonyl complexes. The IR spectra of the acylate/benzoylate complexes (Tables I1 and 111)exhibit three strong u(C0) absorptions at ca. 1930,1840, and 1830 cm-' which is 80-100 cm-' lower frequency than the starting tetracarbonyls and is consistent with the f a c tricarbonyl structure. The 'H NMR spectra of the acylate complexes

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52 the 31P(1H)NMR spectra consists of two overlapping AB patterns (Figure 4) consistent with the presence of two isomeric forms in solution. Similar behavior was observed for the 13C3[3.3-a-ring] acylate complex. Two possible isomers are 52(1) and 52(2) (Figure 4). The 31P(1HJNMR spectra of all the other benzoylate and acylate complexes


Powell et al.

were consistent with a single isomeric form. The encapK. The major sources of error in the measurements resulation of the Li+ cation by a combination of the metsulted from (i) the necessity/difficulty of working with alla-(aza)-crown ether and acylate/benzoylate oxygens dilute solutions of organolithium reagents (< 10-2M),(ii) (nitrogens) in complexes 41-71 has been confirmed by difficulties associated with obtaining a completely dry single-crystal X-ray diffraction studies of the complexes apparatus (glassware + IR cell), and (iii) decomposition “ f a ~ - M o ( C 0 ) ~ ( P h C 0 L i ) P[P2 ~ ” = Ph2POCH2problems. For example, if the addition of a second molar equivalent of RLi resulted in a dramatic increase in the (CH20CH2)2CH20PPh2 ( 5 4 a ) , “ ~Ph2PO(CH2)3NMe~~ I concentration of the M(C0)3(RCOLi)P2product, it was (CH2)30PPh2 (48),30 Ph2PO (CH2)3NCH2CHassumed that some of the original RLi had been decom1 [CH2CH2CH2]CH20PPh2 (53),30and (Ph2POCH2CH2)posed by trace amounts of H20and the result was not used 2NCH2CH20Me(60a)14i30].While the structural studies for K measurements. Additions of more than 3 molar of these and other benzoylate metalla-crown ether systems equivs of RLi often resulted in the decomposition of the are discussed in greater detail elsewhere,30the basic modiphosphinite complex as judged by increased broadness lecular features of the Li+ coordination sphere are illusand a decrease in total intensity of all v(C0) absorptions. trated in Figure 5 and selected bond lengths and bond This tendency toward decomposition increased as the angles are given in Table IV. The benzoylate oxygen O(1) ability of the system to stabilize acyl/benzoylate products and the two phosphinite oxygens O(2) and O(3) together decreased, being particularly pronounced for 10C3 and with the other 0 and/or NMe donor groups adopt conl l C 3 complexes. In a small number of cases in benzene formations which effectively define a cavity of radius -2.0 solutions the acyl/benzoylate product precipitated from A in which the Li+ cation resides. The Li+ coordination solution in the IR cell. geometry in 48 and 53 is essentially a distorted tetrahedral A particularly unusual situation was encountered in the arrangement. For the 13C4 system 54a the benzoylate reaction of RLi with the 12C3[3.3-P-ring] complex 24. For oxygen O(1) and the two phosphinite oxygens O(2) and example the addition of 1.1molar equiv of PhLi to a 7.5 O(3) are, to a first approximation, located at three of four X M solution of 24 in THF solution gave approxi“ideal tetrahedral sites” about Li+ while the two ether mately 1520% of the benzoylate product 53 as judged by oxygens O(4) and O(5) are symmetricallyplaced about the solution IR [v(CO) region]. However, if the reaction is now fourth tetrahedral position. The Li+ coordination in 60a pumped to dryness and the product redissolved in THF, approximates a distorted trigonal-bipyramidal arrangeIR monitoring indicates the solution species to be entirely ment with the axial Li-O(1) and Li-N bonds being notithe benzoylate 53 without any trace of the starting tetracibly longer than comparable bond lengths in the other carbonyl. Although not easily explained, the experimental benzoylate complexes. In these benzoylate complexes the observation is quite reproducible. phosphinite oxygens O(2) and O(3) exhibit trigonal-planar A second approach to assessing the relative stabilities coordination consistent with an sp2arrangement and 0-P of the acylate/benzoylate products 41-72 is to compare The MoC(l)O(l)Li,unit, which is approxtheir rates of decomposition. For example, in CH2C12 imately planar, has bond lengths and bond angles close to solution at 20 “C the approximate tl12’sfor the reaction those reported for the complex Mo(Cp)(MeCO)(CO),of “MO(CO)~(P~COL~)P~” with CH2C12to give ”M(CO)4P2”, (PPhJ. The benzoylate CO bond (ca. 1.26 A) is only and presumably “PhLi CH2C12decomposition products”, slightly longer than a typical C=O double bond, while the increase in the order [2.2(N1Pr)]benzoylate 42 (tl/2 = 14 Mo-C(0)Ph bond (ca. 2.25 A) is approximately 0.1 A h) < [3.3(NMe)]benzoylate 48 (tl = 200 h) < [3.3-P-ring] shorter than expected for a Mo-C(sp2) single bond.15J6 benzoylate 53 (tl = 380 h) lo5 Lemol-' for the 13C4 complexes 25a and 26a. Although the experimental errors (reproducibility) in individual K may be kM%,it seems likely, given that most of the experimental problems result in loss of acylate/benzoylate product (e.g. reaction with trace H20), that the experimental K values in Table V are less than the "true K value" and should only be used as a qualitative guide. The large variation in the experimental K is reflective of the relative Li+ ligating abilities of the product molecules and clearly indicates that 12C3,13C4,and 14C4 metalla-crown ether systems are the most effective. Furthermore the data indicate that preferential Li+ binding by appropriate design and use of P-donor crown ether ditopic ligands can provide 2 9 kcal-mo1-l of additional stabilization vis B vis non-crown ether analogues. Features that favor Li+ binding in the product molecule are as follows: (i) a ligand should be one donor atom short of providing Li+ with a "full"coordination sphere (the 16C5 complex 31 complexes Li+ but does not react to a significant extent with RLi); (ii) the ligand should be of a suitable size (12-14 atom ring); (iii) the ligand must accommodate the stereochemical requirements of the bridging M-RC=O-Li+ unit (molecular models indicate that steric interactions between PPh, and NMe groups for



Table VI. Pseudo-First-OrderRate Constant Data for the Reaction of Lithium Benzoylates with H 2 0 (0.222 M)in T H F (26 “C) complex metalla-crown ether M product complex kobt Q-’ re1 k’ [Mo(CO),(PhCOLi)]’ Mo MO(CO)G 2.2 x 10-3 640 41a 10C3[2.2(NMe)] Mo 12a 0.64 190OOO 43 11C312.31 Mo 14 0.34 100000 7.4 x 10-2 22 OOO Mo 15 44 llC3i2.3iNMe)l 16 0.12 35000 llC3[2.3(NiPr)] Mo 45 17 0.18 54 OOO llC3[2,3(NCHzPh)] Mo 46 3.0 X llC3[2.3-u-ring] Mo 21 8800 50 22 80000 0.27 51 llC3[2.3-/3-ring] Mo 14000 4.7 x 10-2 Mo 18 47 12C3[3.3] 19 7000 2.4 X 12C3[3.3(NMe)la Mo 48 20 23 000 Mo 7.7 x 10-2 49 12C3[3.3(NiPr)] 24 6.0 X 18OOO 12C3[3.3-b-ringl’ Mo 53 23 4.3 x 10-2 12C3[3.3-u-ring] Mo 13OOO 52 13C4[2.2.2]b Mo 4.0 x 10-3 1200 54a 25a 34 W 1.1 x 10-4 54b 25b 13C4[2.2.2] 13C4[2.2.2] 6.7 x 10-3 2000 Cr 54c 25c 2.2 x 10-4 56 27 13C4[2.2.2(NMe)] 64 Mo 1 26a 13C4[2.2.2(NMe),] Mo 3.4 x 10” 55a 2.7 x 10-3 57 28 14C4[2.3.2] Mo 800 30 14C4[2.2.3]b Mo 2300 7.7 x 10-3 59 1.4 X 60a 33a 10C3[2.2(NCH2CH20Me)]a Mo 4300 OStudies of the variation of k o b with [H20]confirms a rate law of the type rate = k[M(CO)3(PhCOLi)P2][H20]. bStudiesof the variation of kob with [H20] confirms a rate law of the type rate = k[M(CO)3(PhCOLi)P2][H20]2. Scheme I 34a effectively prevent this complex from meeting this requirement; the PEt2 analogue 34b does meet the steR,C4~+L:(~~~), C0 reochemical requirements but does not react with RLi); slow \ P ,I + ’RLI’ f o s t (iv) the crown ether donor atoms should be as basic as 1- ’‘h/p-03 ‘P-0 possible. Thus for donor groups in the hydrocarbon backbone NMe > 0 (e.g. compare 26a with 25a and 19 with 18-Table V) while a Ph2P0 system is much better than a Ph2PNMe system (compare 34a and 34b, K < lo-’ with 19). The lack of reactivity in ‘‘hPNMe systems” can be ascribed to N-P ?r-delocalizationof the nitrogen lone ‘P - 0 4 pair that effectively reduces the basicity of the P-N unit well below that for P-0.3l Delocalization of one of the P-O oxygen lone pairs onto phosphorus is also apparent in the unfavorable energetics associted with RLi addition to CO molecular structures of the benzoylate complexes (Figure to give a solvated acylate/benzoylate intermediate of the 5 ) where the bond angles about the phosphinite oxygens type “M(C0),((RC0)Li(THF).Jp,”. This step would be are consistent with trigonal-planar oxygen (e.g. for 55a followed by subsequent rapid loss of solvent THF and Li+ LPOC = 123’; LPOLi = 120’; LLiOC = 117°)).11130 encapsulation. Clearly, to some degree these subsequent Previous kinetic investigations of the addition of MeLi steps will be influenced by conformational changes/ento a range of group 6 metal carbonyl complexes have shown ergetics of the metalla-crown ether systems which, intuikf for the reaction of M(C0)6 with MeLi to give Mtively, may be more pronounced for the bicyclic wring and (C0)5(MeCOLi)to be approximately2 orders of magnitude /3-ring systems 21-24. The following points should be greater than kf for the reaction of M(CO),(PR,) with noted: (i) for simple crown ether-group 1A cation systems MeLi.36 Variation of M or PR3 had little effect on kf. both kf and kd are fast and frequently studied by NMR While kinetic studies of crown ether-cation and crypor T jump methods;37(ii) for M(CO)4(PPh20Me)2 RLi tand-cation complexation reactions are far from extenthere is no evidence for the formation of a M(CO)4~ i v ea, general% ~~ though far from absolute o b s e r ~ a t i o n ~ ~ (PPh20Me)2.RLiadduct in which Li is complexed by the is that the decomplexation rate constant k d is a dominant phosphinite oxygens;40and (iii) for the 13C4[2.2.2(NMe)2] factor controlling the ligating abilities of crown ether and 14C4[2.3.2(NMe)2]tetracarbonyl complexes 26 and systems ( K = /&-I). For the metalla-crown ether + RLi 29 the probable prior formation of adduct molecules “[Mreactions (e.g. eq 6) it seems likely that kfwill be similar (C0)4P2]RLi”,in which the -NMe(CH,),NMe- moiety for most of the complexes studied being dominated by the chelates an RLi unit in a similar fashion to tetramethyleth~lenediamine,,~ provides an additional complexity to the mechanism of both the forward and back reactions. (36) Dobson, G. R.; Paxson, J. R. J.Am. Chem. Soc. 1973,95,5925. A simple schematic of the perceived mechanism of acy(37) (a) Kasprzyk, S. P.; Wilkins, R. G. Inorg. Chem. 1988,27,1834. (b) Liesengang,G. W.; Farrow, M. M..; Vazquez, F. A,; Purdie, N.; Eyring, late/benzoylate formation is given in Scheme I. E. M. J. Am. Chem. SOC.1977, 99, 3240. (c) Fusl, P.; Lagrange, J.; In contrast to simple crown ether-M+ interactions the Lagrange, P. J.Am. Chem. SOC. 1985,107,5927. (d) Loyola, V. M.; Pizer, back reaction (kd) of eq 7, which leads to the formation R.; Wilkins, R. G. J. Am. Chem. SOC. 1977, 99, 7185. (e) Cox, B. G.; Schneider, H. J. Am. Chem. SOC. 1977,99,2809. (fJLockhart,J. C. Adu. of “M(CO),P2” and RLi and subsequent irreversible deInorg. Bioinorg. Mech. 1982, 1, 217. (8) Lincoln, S. F.; Brereton, I. M.; composition of RLi by a fast reaction with H20, is rather Spotawood,T. M. J. Am. Chem. SOC.1986,108,8135.

,typ3

+

(38) (a) Lehn, J. M.; Sauvage, J. P.; Dietrich, B. J. Am. Chem. SOC. 1970,92,2916. (b)Loyala, V. M.; Wilkins, R. G.; Pizer, R. J. Am. Chem. 187, 1391. (b) Aalmo, K. M.; Krane, J. Acta

(40) Adduct formation is observed between the methyl o-phenylene phosphite complex cis-Mo(CO),(P(OMe)02C6H&and RLi. Powell, J.; Kuksis, A.; May, C. J.; Meindl, P. E.; Smith, S. J. Organometallics, following paper in this issue.


Powell et al. Scheme I1 R

;m II

fast

t 2 H20 (v. slow)

slow

fast

h

J

9 a

h h

c c

slow (see Figure 6). The slow rate of reaction is probably reflective of the high energetics associated with decomplexation of the crown ether moiety and formation of M(CO),((RCO)-Li(THF),)P,. The large variation in reaction rates and the variation in rate law as a function of the structure of the metalla-crown ether supports this hypothesis. Note that for the 12C3 systems 48 and 53 and the lariat ether system 60a the rate of reaction 7 = kd[M(CO),(RCOLi)P,] [HzO] while for 13C4 54a and the 14C4[2.2.3] system 59 the rate of reaction 7 = kd[M(CO),(RCOLi)P,] [H20lZ(Figure 7). While one HzO is probably involved in the RLi destruction step, it seems likely that the second H20 molecule in the 13C4 and 14C4 systems is intimately involved in the Li+-decomplexation process. Since the THF solvent should be as effective as HzO as a "simple cation solvating ligand", it seems likely that HzO to ligand hydrogen bonding effects play a significant role in facilitating the Li+ decomplexation process. Previous studies of the rates of cryptand-cation decomplexation rates have concluded that the ability of water to enhance the rate of cryptand decomplexation (kd) can be ascribed to H20-cryptand donor atom hydrogen bond effects.41 Possible reaction pathways for reaction 7 are given in Scheme 11. Identifiable trends in benzoylate stability, as reflected by the pseudo-first-order decomplexationrate constant kd for the reaction of "M(CO),(RCOLi)P; with HzO in THF (eq 7; Table VI), are as follows: (i) ring size effects14C4[2.3.2] 1 13C4[2.2.2] L 14C4[2.2.3] > 12C3[3.3] > 11C3[2.3] (least stable-largest kd); (ii) the replacement of ether 0 atoms with NMe leads to increased stability, e.g. 13C4[2.2.2(NMe).J > 13C4[2.2.2(NMe)] > 13C4[2.2.2] and 12C3[3.3(NMe)]> 12C3[3.3]; (iii) W > M o > C n e e data for the 13C4[2.2.2] systems; (iv) replacement of NMe with N'Pr or NCHzPh groups enhances kd and destabilizes the benzoylate; (v) for the fused-ring systems the wring is more stable than the ˚ and (vi) surprisingly k d for the llC3[2.3-(u-ring] is smaller than that of the 12C3[3.3wring]. This reversal of ring size effects may reflect an increased rigidity in the llC3[2.3-a-ring] system. High lithium ion specificity has been previously observed for 13-crown-4 and 14-crown-4 compounds with pendant carboxylic acid groups structurally similar to the 13C4 and 14C4 benzoylate complexes described herein.42 The effect (41)COX,B. G.; Garcia-Rosa, J.; Schneider, H. J. Am. Chem. SOC. 1981, 103, 1054.



of 0 replacement by NMe is consistent with previous observations of strong interactions between Li+ and tertiary amines.32 For comparative purposes the relative rate constants k', based on k'= 1for the reaction of the very stable benzoylate [Mo(CO)~(P~COL~)(P~~POCH~(CH2NMeCH2)2CH20PPh2) (55a) with H 2 0 in THF, are Figure 9. Pwible polymeric structure in the insoluble complexes also given in Table VI. For isolable benzoylate complexes ~ ~ ~ - [ M O ( C O ) ~ X ( P ~ ~ P O C H ~ ( C H ~(74) O C(X H ~= ~ ~ C H ~ O P C1, Br). the difference in kd for the most vs least stable systems (i.e. [2.2.2(NMe)2]55a vs [2.3(NMe)] 12a) is a factor of 1.9 X lo5. A further measure of the significance of preferential Li+ binding by the product molecule on overall benzoylate stability is obtained from the similarity of the kd values for the 13C4[2.2.2(NMe)J complex 55a and Mo(CO),(PhCOLi) (Table VI). This suggests that the Figure 10. deactivation of PhLi addition to coordinated CO associated The marked insolubility of the lithium halo complexes with PR3 substitution on going from MO(CO)~ to cis-Mo[Mo(CO)3X(Ph2POCH2(CH20CH2)2CH20PPh2)lLi (74; eq (CO),(PR,), has been very significantly though probably 9) is suggestive of a polymeric solid-state structure, possibly not totally offset by the presence of the metalla-aza-crown of the kind illustrated schematically in Figure 9. ether and Li+ binding effects. Attempts to prepare a formylate complex from the reaction of the 13C4[2.2.2] Conclusions metalla-crown ether complex 25a with either LiA1H4 or LiBHEt3 in THF were not successful and IR monitoring In the area of ditopic ligand chemistry focused toward indicated unreacted starting material. However reaction the synthesis of transition-metal-group 1A/2A cation of the 13C4[2.2.2(NMe)2]complex 26a with excess LiAlH, systems, with a view to obtaining cooperativity effects in the reactions of coordinated ligands,'-14 the metalla-crown in THF produced an orange solution and resulted in the ether/RLi systems herein described represent one of the complete loss of the tetracarbonyl u(C0) absorptions of 26a more significant effects so far observed. The structural and the generation of new absorptions at 1925 s and 1830 s br cm-'. This solution IR [v(CO) region] is very similar features and the high lithium ion selectivity of the 12C3, to that of the acylate complex M o ( C O ) ~ ( M ~ C O L ~ ) - 13C4, and 14C4 benzoylate and acylate complexes are similar to those of a series of Li+-13C4/14C4 crown eth(Ph2POCH2(CH2NMeCH2)2CH20PPh2J (67a) consistent er-carboxylate systems.42 While these latter systems exwith the possible formation of a formylate complex, Mohibited a Li+/Na+ selectivity (extraction ratio) varying (CO)3(HCOLi)(Ph2POCH2(CH2NMeCH2)2CH20PPh2} (79) from 1to 20, the systems described here appear to exhibit (eq 11). However attempts to isolate 79 were not suca much greater preference for Li+ binding with no evidence Me for the formation of Na+ benzoylate analogues from the H,c+o\ 1 L' N\> reaction of the metalla-crown ether tetracarbonyls and 550 + E x c e s s LlAlH, (oc)~ho-~20j.N-Me NaPh. The most effective ditopic ligands with respect to \ Ph2 P - d + AIH, benzoylate/acylate formation are ones that maximize Li+ binding in the product molecule. The current study shows (eq 1 1 ) that long-chain a,w-bis(dipheny1phosphinite)polyether 79 ditopic ligands can be successfully complexed in a cis cessful with reversion to the tetracarbonyl complex 26a manner to substitutionally inert 18-electron metal combeing the major result of workup. 'H NMR monitoring plexes to generate chemically interesting metalla-crown of THF-d8 solutions of 26a + excess LiAlH, (eq 11) did ether systems that exhibit significant cooperativity effects. not identify a resonance attributable to a formylate proton. However, the extension of this approach to substitutionally Besides ligand proton resonances a very broad resonance labile complexes requires further structural modification was observed that may be associated with formylate 79 e to the ditopic ligand. For example the ligand AlH3 and AlH3 .s AlH4- hydride exchange processes. Ph2POCH2(CH20CH2)2CH20PPh2 (8) (which is the preAttempts to prepare sodium benzoylate complexes from cursor to the 13C4[2.2.2] complexes 25) reacts with Rh2the reaction of NaPh with metalla-crown ether tetraC12(CO), to give the complex trans-[Rh2C12(CO)2carbonyl complexes 25,26,31, and 32 were unsuccessful. (Ph2POCH2(CH20CH2)2CH20PPh2)2] which contains a While an indication of possible reaction between the 19C6 26-atom ring, reacts with PdC12(PhCN)2to give cis- + complex 32 and NaPh was given by a color change from trans-PdC12(Ph2POCH2(CH20CH2)2CH20PPh2), and recolorless to pale yellow, the IR specrum v(C0) region acts with Pt2CI,(C2H4), to give cis-Pt2C1,(PhzPOCH2showed no evidence of benzoylate formation. This ob(CH20CH2)2CH20PPh2J2 (26-atom ring).43 A suitably servation indicates a very high lithium ion specificity in modified ligand that should be capable of providing strong the 12C3 and 13C4 acylate/benzoylate complexes. LikeLi+ binding in acyl/ benzoyl complexes of substitutionally wise reaction of the metalla-crown ether tetracarbonyls labile systems is the cis-chelating macrocyclic ligand shown with RMgX reagents did not lead to acylate/ benzoylate in Figure 10. Attempts to prepare this ligand and complexes. structural analogues are currently in progress. Exploratory studies of the reactivity of the stable benExperimental Section zoylate/acylate complexes 54f and 66 indicate that these complexes are sufficiently stable to be converted to alk'H, l3C('H},and 31P(1HJ NMR spectra were recorded on one of the following instruments: Varian T-60, CFT-20,XL-200, or oxycarbene derivatives (eq 8) and hydroxycarbene derivXL-400spectrometer. Infrared spectra were recorded on Nicolet atives (eq 10). 5DX, lODX, and 7000 series Fourier transform infrared spectrometers using 0.5" NaCl solution cells. Elemental analyses +

(42) Bartsch, R. A.; Czech, B. P.; Kang,S.I.; Stewart, L. E.; Walkow1985, iak, W.; Charewicz, W. A.; Heo, G . S.; Son, B. J. Am. Chem. SOC. 107, 4997.

(43) Powell, J.; May, C. J., manuscript in preparation.

2930 Organometallics, Vol. 8, No.12, 1989

Powell et al.

were done by Canadian Microanalytical Laboratories, Vancouver, British Columbia, Canada. All reactions were carried out under a nitrogen atmosphere. Dichloromethane was distilled from P,O,; pyridine was distilled over KOH triethylamine (EGN) was distilled over Lm, diethyl ; ether, tetrahydrofuran (THF), and benzene were distilled from sodium benzophenone ketyl. The tertiary phosphines diphenylchlorophosphine, diethylchlorophosphine, and diisopropylchlorophosphine were purchased from the Aldrich Chemical Co. and Strem Chemicals. Diphenylchlorophosphinewas distilled (reduced pressure) prior to use. Phenyllithium and methyllithium solutions were purchased from the Aldrich Chemical Co. and standardized with diphenylacetic acid prior to use. Di- tri-, tetra-, and pentaethylene glycols, 1,3-propanediol, 1,5-pentanediol, l,l,l-tris(hydroxymethyl)ethane,isopropylamine, 2-methoxyethylamine, bis(2-hydroxyethyl)methylamine, N,N'-dimethyl1,2-diaminoethane, N,N'-dimethyl-l,3-diaminopropane,and 3,3'-methyliminobis(N-methylpropylamine)were purchased from the Aldrich Chemical Co., dried over KzCO3, and distilled under reduced pressure prior to use. Published methods were used to prepare [(2,5-norbornadiene)M(CO),] (M = M O , Cr," ~ We), acetaldehyde ethyl acetal,a 3-bromopropyl 1,2-ethanediyl bis(tol~enesulfonate),4~ N-(3-hydroxypropyl)methylamine,@N42hydroxyethyl)-N-(3-hydroxypropyl)methylamine,@, bis[N-(3hydr~xypropyl)]methylamine,~~ bis[N-(3-hydroxypropyl)]isop r ~ p y l a m i n e , ' ~N-(3-hydroxypropyl)-2-(2-hydroxyethyl)p i ~ e r i d i n e , ,and ~ N-(3-hydroxypropyl)-3-(hydroxymethyl)piperidine.@ Preparation of a,w-Diols. 4-Oxa-1,7-heptanediol was prepared from the monosodium salt of 1,3-propanediol and acetaldehyde ethyl 3-bromopropylacetal (Br(CH.J3OCH(OEt)CH,) following the method of Newman et al.49(eq 12). Following a OEL

f i OH N " - - HO f\

HO

To'

HO

OCH CH3 I

OEi

Br(Ct+)30dHCH3

ONa

Hf_

-NaBr

4HO

ELOH + C H 3 C H 0

OH

(eq. 12)

similar procedure the following diols were obtained 3-oxa-1,6hexanediol in 73% from HOCH2CH20Naand Br(CH2)30CH(OEt)CH3; 3,Cdioxa- 1,g-nonanediol in 55% yield from HOCHzCHzOCHzCHzONaand Br(CH2)30CH(OEt)CH3;and 4-oxal&octanediol in 40% yield from HO(CHz),ONa and Br(CHZ)30CH(OEt)CHS. Synthesis of 3,7-Dioxa-1,9-nonanediol. To 373 mL (6.70 mol) of 1,2-ethanediol was added 38.6 g (1.68 mol) of sodium metal. The suspension was heated (100-105 "C) to give a thick orange mixture. 1,3-Propanediylbis(to1uenesulfonate) (322 g, 0.87 mol) was added and the mixture cooled to maintain a temperature of 100-105 "C. After being stirred for 2 h, the mixture was cooled. Sodium ptoluenesulfonate precipitated. The mixture was distilled under reduced pressure to remove excess 1,2-ethanediol. The residue in the still pot was then extracted with CH2C1, The CH2C12was removed under vaccuo and the liquid remaining distilled under reduced pressure. Those fractions containing product, as determined by 'H NMR spectroscopy,were combined and redistilled, under reduced pressure, to give the product as a colorless liquid; bp 295 "C (760 mmHg); 5% yield. 1,l-Bis(hydroxymethy1)- 1-(methoxymethyl)ethane, (HOCH2)&(OMe)CH3. (i) Synthesis of the Cyclic Acetal of Tris(hydroxymethy1)ethane. To a 250-mL, three-neck, round-bottom flask equipped with a condenser, Dean-Stark tube, (44) Werner, J.; Prinz, R. Chem. Ber. 1977,100, 265. (45) Fronzaglia, A.; King, R. B. Znorg. Chem. 1966,5, 1837. (46) Eaton, P. E.; Cooper,G.F.; Johnson, R. C.; Mueller, R. H. J . Org. Chem. 1972,37, 1947. (47) Fieser, L. F.; Fieser, M. Reagents for Organic Synthesis; Wiley: New York, 1967; Vol. 1. (48) Powell, J.; James, N.; Smith, S. J. Synthesis 1986, 338. (49) Newman, M. S.; Barbee, T. G.,Jr.; Blakesley, C. N.; Din, Z.; Gromelski, S.; Khanna, V. K.; Lee, F. L.; Radhakrishnan, J.; Robey, R. L.; Sankaren, V.; Sankarappa, S. K.; Springer, J. M. J . Org. Chem. 1975, 40, 2863.

magnetic stirrer, addition funnel, and a N2 inlet were added 10.16 g (0.08 mol) of CH3C(CHzOH)3,150 mL of dry THF, and 2.57 g of paraformaldehyde. Eight drops of CH&3O3H in 8 mL of c$& were added dropwise. The solution was refluxed. When no more water was collected in the Dean-Stark tube, 2.03 g (0.02 mol) of Na2CO3was added, the mixture filtered, and the filtrate evaporated to a colorless oil. The oil was distilled under reduced pressure to give the product (the cyclic acetal CH,(HOCH,)CCH20CHz0CHz)in 86% yield; bp 104-106°C (2 mmHg). I (ii) Synthesis of CH3(CH30CHz)CCH20CH20CHpTo a lOO-mL,three-neck, round-bottom flask equipped with a magnetic stirrer, Nz inlet, and an addition funnel and flushed with Nz was added 45 mL of dry pyridine and 3 mL (0.04 mol) of CH3SOzC1. The solution was cooled in an ice bath. To the addition funnel was added 5 mL of dry pyridine and 2.5 mL (0.02 mol) of the cyclic acetal prepared in part i. This solution was added dropwise to the CH3SOzCl/pyridinesolution. A white solid slowly began to precipitate. After being stirred 1h, the mixture was poured into a 250-mL Erlenmeyer flask containing ca. 100 mL of HzO/ice. The solution was extracted with E a 0 (80 mL). The combined E a 0 extracts were washed with a 1:l 12 M HCl:H20 solution and finally with HzO. The E a 0 layer was collected, dried over K,C03/Na2S04,and filtered and the filtrate evaporated to give a white solid. The white solid was recrystallized from hexane to * give CH3(CH30CH,)CCH20CH20CHzas a fine white powder in 35% yield. (iii) Degradation of the Cyclic Acetal. To a hot suspension of 16.9 g (0.09 mol) of 2,4-dinitrophenylhydrazinein 380 mL of 5 M HCl was added 11.7 g (0.08 mol) of CH3(CH30CH2)Cz Hz0CH20CH, The mixture was heated on a steam bath ca. 20 min and then stirred at room temperature overnight. The orange mixture was filtered and the orange solid collected and washed with H20. The aqueous filtrate and washings were combined and neutralized with a saturated NaHC03 solution. The solution was then extracted with C6Hs until the aqueous layer became pale yellow. The aqueous layer was collected and evaporated to a cream colored solid/oil residue. The residue was distilled under reduced pressure to give the product [CH30CH,C(CH3)(CHzOH),]as a colorless liquid, bp 125 "C (6 mmHg); 55% yield. Amino Diols. N,"-Bis(2-hydroxyethyl)-N,"-dimethyl1,2-diaminoethane. To 22.5 mL (0.20 mol) of N,"-dimethyl1,2-diaminoethane cooled to -40 "C in an acetone-dry ice bath, acidified with 0.08 mL (0.01 mol) of 12 M HCl and 1.5 mL of H20, was added 21 mL (0.42 mol, 5% excess) of ethylene oxide. The solution was stirred with a mechanical stirrer at 5-10 "C for ca. 4 h and then left to stir at room temperature overnight. The resulting mixture was distilled under reduced pressure to give the product as a colorless liquid 36% yield; bp 302 "C [lit.mbp 150-153 "C (9 mmHg)]. Similarly prepared from the reaction of excew ethylene oxide with the given amine were the following. N,WBis( hydroxyethy1)-N,W-dimethyl-1 , 3 - d d n o p r o p a n e from N,"-dimethyl-l,3-diaminopropane: isolated as a colorless liquid; 60% yield; bp 120-125 "C (0.1 mmHg). 2-[(2-Hydroxyethyl)methylamino]ethyl2-hydroxyethylether from bis(2hydroxyethy1)methylamine: bp 95-105 "C (0.5 mmHg); 79% yield. Bis(2- hydroxyethy1)isopropylamine from isopropylamine: bp 95-110 "C (0.05 mmHg); 83% yield. N-(2-Hydroxyethy1)N-(3-hydroxypropyl)benzylamine from N-(3-hydroxypropy1)benzylamine: bp 130-140 "C (0.3 mmHg); 76% yield. Bis(2-hydroxyethyl)(2-methoxyethyl)amine from 2-methoxyethylamine: bp 100-105 "C (0.7 mmHg); 72% yield. N 4 2 Hydroxyethyl)-2-(2-hydroxyethyl)piperidinefrom 242hydroxyethy1)piperidine: bp 130-135 "C (0.7 " H g ) ; 70% yield. N-(2-hydroxyethyl)-3-(hydroxymethyl)piperidinefrom 3(hydroxymethy1)piperidine: bp 175-185 "C (1.0 mmHg); 90% yield. a,o-Bis(dipheny1phosphinite)ligands were prepared as outlined in eq 2. A typical procedure is illustrated for the synthesis of 4-oxa-1,7-heptanediyl bis(dipheny1phosphinite). To a solution of 2.4 g (0.02 mol) of 4-oxa-l,7-heptanediol and 5.8 mL (0.04 mol) of EbN in 125 mL of dry benzene cooled to +5 "C in an ice bath was added 7.2 mL (0.04 mol) of PhzPCl in 5 mL of I

-

(50) Jezo, I.; Luzak, I. Chem. Abstr. 1967, 67, 100355~.



transfer tubes, IR cells etc. were scrupulously dried and purged benzene, dropwise with stirring. A white precipitate (triethylwith dry argon.) Typically 140 mg (187 pmol) of MO(CO)~ammonium hydrochloride)slowly formed. After being stirred for I I 1h, the mixture was filtered under nitrogen via Schlenk tube to (Ph2POCH2CH2CH~NCH2CH(CH~OPPh2)CH2CH&H~) (24)was remove [E@JH]Cl. Evaporation of the fiitrate yielded the product dissolved in 20 mL of dry THF. Thus, if the volume of solution as a colorless, viscous oil, 92% yield. The oil was characterized is negligible, the initial concentration [24] = 9.332 X M (0.5 by lH and “P{lH)NMR spectroscopy. If the spectrum integration mL of this solution was transferred to an IR solution, cell to record was not close to that expected, the oil was not used in subsequent the infrared spectrum). Recently standardized MeLi ([MeLi] = reactions and the synthesis repeated. 1.39 M] (65.0 mL, 90.3 pmol, 0.484 equiv) was added to the bulk Metalla-crownether complexes were prepared as outlined solution of 24 and the solution stirred for 15 min. A 0.5-mL sample in eq 3. A typical reaction is illustrated for the synthesis of the 13C4[2.2.2] complex cis - M O ( C O ) ~ ( P ~ , P O C H ~ was - removed to record the infrared spectrum. Addition of RLi and sampling were repeated until complete reaction had occurred (CH20CH2)2CH20PPh2) (25a). A solution of 15.84 g (52.8 mol) or 5 equivalents of organolithium added. The concentration of of Mo(CO)~NBDwas dissolved in 250 mL of dry CHzClzand unreacted 24 was determined from the absorbance of the 2024 loaded into a 250-mL Marriotte-type pressure-equalizing constant cm-l v(C0) band. addition funnel. Exactly 1 equiv of Ph2POCH2Determination of the Rates of the Reactions of the Acylate (CH20CH2)2CH20PPh2 (27.37 g, 52.78 mmol) was dissolved in and Benzoylate Complexes “M(C0)3(RCOLi)Pg(41-69) with 250 mL of dry CHzClz and placed in a second Marriotte-type Water in THF Solution at 26 OC (Eq 7). In a typical reaction pressure-equalizingconstant addition funnel. The two solutions 81.3 mg (0.109 mmol) of Mo(CO),. .were then added simultaneouslyand dropwise to 3500 mL of dry I CH2Cl2over a period of 15-20 h. The whole apparatus was (Ph2POCH2CH2CH2NCH&H(CH20PPh2)CH&H&H2) (24)WM shielded from light as much as possible. After the addition of dissolved in 20 mL of drv benzene and 126 mL 10.218 mmol. 2 the two reactant solutions was complete, the mixture was stirred equiv) of 1.73 M PhLi added. The solution immediately turned for 72 h a t 20 “C. The solvent was then concentrated to 55 mL orange from pale yellow. The solvent was removed in vacuo and on a rotary evaporator. Acid-washed cellulose powder (400 mL) the orange benzoylate product 53 dried at 25 “C at less than 0.01 was then stirred into the concentrated reaction mixture. The mmHg for 30 min. Complex 53 + unreacted PhLi were redissolved solvent was removed by rotary evaporator,suspending the residue in 20.0 mL of H,O/THF where the initial water concentration on the cellulose powder. The “cellulose powder/reaction residue” [H20] = 0.133 M and [Mol = 5.42 X M. The instant the was dried in vacuo and added to the top of a 30-mm diameter water/THF solution is added represents time t = 0. The solution column packed with glass wool, sand, and a 60-cm column length was vigorously mixed for 10 s and ca. 1.0 mL of the reaction of “Florisil” (magnesium silicate) and more sand (bottom to top mixture placed in a previously dried 0.1-mm cesium fluoride description of column packing) and filled with hexanes. The infrared cell. The charged infrared cell was then placed in the column was eluted with ca. 1 L of ACS hexanes, 2 L of 1:l hexsample compartment of the Nicolet lODX Fourier transform anes/CHzClz,and 2 L of CHzClzand then stripped by using 500 infrared spectrometer with the compartment temperature held mL of acetone. The hexane/CHzClZand CHzClzfractions were constant (26.0 “C) by dry air purge. The infrared spectrum was combined and reduced to 250 mL by rotary evaporator. A further then recorded as a function of time. The natural logarithum of 150 mL of hexanes was added and the solution reduced to 50 mL the absorbance changes of the lowest energy v(CO),carbonyl ligand during which time a white crystalline solid precipitated from stretching band, for the benzoylate complex (1844 cm-’ in the case solution. The product M O ( C O ) ~ ( P ~ ~ P O C H , - of complex 53) plotted as a function of time is given in Figure (CH20CH2)2CH20PPh2) was collected on a fritted glass crucible 6. The initial water concentration was varied, and similar kinetic and recrystallized from CHzC12/hexanes(or pentanes). The yield “runs” were determined. Plots of kob vs [H20]and a plot of kob of Mo(C0)4(Ph2POCH2(CH20CHz)2CHzOPPh2) (25a) was 28.5 vs [H20I2for the reaction of 54a with HzO in THF are given in g (39.3 mmol, 74%). The tungsten and chromium analogues 25b Figure 7. As the benzoylate is synthesizedby using 2 molar equiv and 25c, respectively, were synthesized as described above except of PhLi, the reaction of the benzoylate with water takes place that the reagents M(CO),(NBD) (M = W, Cr) and the ct,w-bisin the presence of a molar equivalent of LiOH. Aa a check to show (diphenylphosphinite) ligand were added over a period of 12 h that the LiOH does not influence the rate of the reaction, the to 3 L of refluxing benzene followed by a further period of reflux reaction was also carried out by using the isolated and recrysof 48 h. The metalla-crown ether complexes 11-33,34a, and 35 tallized benzoylates 55a and 51. The rate of the reaction (eq 7) were synthesized following the above procedures. Isolated yields was the same as that using the above procedure starting with were generally in the range 50-90%. The isolated yields of 34b, “M(CO)4P2+ 2PhLi”. 36, and 37 were 8, 5, and 12%, respectively. Selected characfac -[Mo(CO)3(C(OMe)Me]{Ph2POCHz(CHzOCHz)zCHzterization data for complexes 11-37 are given in Table I. OPPh,] (73a). The acylate complex 66a (0.186 g) was dissolved Isolation of acylate and benzoylate complexes 41-71 is in CHzC12(40 mL). To this was added a solution of 40 pL of illustrated by the synthesis of the 13C4[2.2.2] benzoylate complex methyl fluorsulfonatein 5 mL of CH2C12 (Me30+BF4-could also [Mo(CO)3(PhCOLi)(Ph,POCH,(CHzOCH,),CH,0P)(54a)(eq be used.) The reaction was stirred for 2 h and extracted with HzO 5). In a typical reaction 4.31 g (59 mmol) of MO(CO)~(50 mL) and the CHzClz layer separated and dried (MgS04). (Ph,POCH~(CH20CH2)2CH20PPhz] (25a)was dissolved in 50 mL Evaporation to dryness under vacuo gave a dark brown oil that, of dry benzene and 4.73 mL of 1.38 M phenyllithium (1.1equiv) on addition of 3 mL of acetone, gave 73a as orange prisms (0.130 added. The pale yellow solution went immediately orange and g, 68% yield). an orange precipitate formed. The orange precipitate [Mofac-[Mo(CO)3(C(OH)Ph)(Ph,POCH,0CH,),CH,0(C0),(PhC0Li)(Ph~0CH,(CH20CH~&H,0PPh2)] was collected PPh,) (75a). MO(CO)~(P~~POCH~(CH~OCH~)~CH~OPP~~) (25a) on a fritted crucible in 93% yield. Recrystallization from (3.18 g, 4.38 mmol) was dissolved in 75 mL of dry benzene and CH,Clz/pentane gave orange/red crystals in 79% yield. The 1OC3, 1.1equiv of phenyllithium added. An orange precipitate formed llC3,12C3,13C4, and 14C4 complexes 12-30 and complexes 33 immediately. The solvent was removed in vacuo and the orange reacted similarly with PhLi to give benzoylates as orange products residue redissolved in 50 mL of dry CH2C12. Distilled Me3SiC1 and with MeLi to give acylates as yellow products. In some cases, (0.56 mL, 4.41 mmol) was added and the mixture immediately however, the benzoylate/acylate product does not precipitate from turned intense blood red. The mixture was stirred for 1h at 10 the benzene solution. In these instances the solvent benzene was “C and then transferred to a 125-mL separatory funnel and 25 removed in vacuo and the residual product dissolved in 25 mL mL of distilled HzO added. The blood red solution was shaken dry CH2C12,filtered through glass wool and a fine glass frit, and and upon contact with the water immediately turned intense either crystallized by using pentane or, for the less stable products, red/black. The organic fraction was extracted twice more with evaporated rapidly to dryness (vacuo)to give the required product as a glass or powder. Analytical data and selected spectroscopic 25 mL of distilled water, then dried over MgS04,and filtered and data are given in Tables ZZ and ZZZ. the solvent removed in vacuo. The intense red/black residue was Determination of the Equilibrium Constant K for the recrystallized from a minimum of acetone to yield 75a as dark red crystals, 2.11 g (2.62 mmol, 60%). The tungsten analogue Reaction of the Group 6 Tetracarbonyl Metalla-Crown 75a was likewise isolated in 80% yield. Ether Complexes 11-37 with RLi. (All apparatus, solution I

2932 Organometallics, Vol. 8,No. 12, 1989

Powell et al.

Ph2PO(CH2)2NiPr(CHz)30PPh2, 123170-45-6;Ph2PO[Mo(CO),ClIPh~OCHz(CHzOCH2)2CHzOPPhz}]-Li+ (74a). T o a solution of [ M o ( C O ) ~ ( P ~ C O L ~ ) ( P ~ ~ P O(CH2)2NCH2Ph(CH2)30PPhz, CH~123170-46-7;PhzPO(CH2)30(CH2),OPPh2, 123170-47-8; (CH20CH2)2CH20PPh2) (54a)in 20 mL of dry CHzClzwas added Ph2PO(CH2)3NMe(CH2)30PPh2, 1.25mL of a 0.44M solution of HCl in dry benzene. The orange 123170-48-9;Ph2PO(CH2)3NiPr(CHz)30PPh2, 123170-49-0; solution immediately turned intense red (presumed formation Ph2PO(CHZ)2N(CH2)4CH(CH2)2OPPhz, 123170-50-3; Ph2POof the hydroxycarbene 75a). After being stirred for 30 min, the (CH2)zN(CHz)3CHCH2CHzOPPhZ, 123170-51-4; PhZPOsolution had turned pale yellow. The solvent was removed in vacuo and the residue washed with 4 X 25 mL of hot hexane to (CH2)3N(CHz)4CH(CHz)20PPh2,123170-52-5;Ph2PO(CH2)3remove benzaldehyde to give 74a as a relatively insoluble off-white N(CH2)3CHCH2CH20PPh2, 123170-53-6; Ph2PO(CH2)2NMesolid (0.32g, 84% yield). The bromo analogue 74b was similarly (CHz)zNMe(CH2)20PPh2,123170-54-7;Ph2PO(CH2)zNMeprepared in 65% yield from 54a and HBr. Preparation of 74a (CH2)20(CHz)zOPPhz, 123170-55-8; PhzPO(CHs)zO(CH2)30and 74b in 80% yield could also be achieved from the reaction PhzPO(CH2)2NMe(CH2)3NMe(CH2)z0PPh2,123170-56-9; of 54a with a suspension of LiCl or LiBr in refluxing toluene. ~~c-Mo(CO)S(P( OMe)3}(Ph~OCH2(CH2OCH2)zCHzOPPh2} (CH2)20PPh2,123170-57-0;Ph2PO(CH2)20(CH2)20(CH2)3OPPh2, Ph2PO(CH2)zN(CH2)20Me(CH2)20PPh2, 85429-60-3; (77). T o a mixture of [ M O ( C O ) ~ B ~ ( P ~ ~ P O C H ,123170-58-1; PhzPNMe(CHz)3NMe(CH2)3NMePPh2, 123170-59-2; EhPNMe(CH20CH2)2CHz0PPh2J]-Li+ (74b)(0.51g, 0.65mmol) and dry (CHz)3NMe(CHz)3NMePPh2,123170-60-5;Ph2POCH2CHAgNO, (0.12g, 0.70mmol) in 40 mL of CHzClzwas added 81 WL (CH20Me)CHz0PPh2,123170-61-6; iPr2PO(CHz)20(CHz),0PiPr2, of P(OMe),. This reaction was stirred for 30 h. Removal of the 123188-14-7; Et2PO(CH2)30(CH2)30PEh,123170-62-7; Ph2POsol-vent (vacuo)followed by 1:l ether/hexane extraction gave, after (CH2)30(CH2),0PPh2,123170-63-8; HO(CH2)zNiPr(CH2)20H, removal of the extraction solvent, 0.38g of 77as an off-white solid (70% yield). The tBuNC complex [Mo(CO)~(~BUNC)- 121-93-7;HO(CHz)zNiPr(CH2)30H,19344-31-1;HO(CH2)zNCH2Ph(CH2)30H,19344-33-3;HO(CH2)2NMe(Ph2POCH2(CH20CH2)zCH20PPhz) (78)was similarly prepared (CHz)2NMe(CH2)20H,14037-83-3;HO(CH2)20(CH2)2NMein 40% yield. Complexes 77 and 78 were unreactive toward RLi (CHz)20H, 68213-98-9; HO(CH2)2NMe(CH2)3NMe(CHz)20H, addition to the CO or tBuNC ligands.

. . .

10394-83-9;HO(CH2)zN(CHz)z0Me(CH2)20H, 79402-97-4; (HOCH2)2C(OMe)CH3, 5164-20-5; 'Pr2PC1,40244-90-4; Et2PCl, 686-69-1; PhzPCl, 1079-66-9; HO(CH2)30(CH2)40H,123170-64-9; Mo(CO),(NBD), 12146-37-1; W(CO),(NBD), 12129-25-8; Cr(CO),(NBD), 12146-36-0; HOCH2CHz0Na,7388-28-5; HOCH2CHO(CH2),0Na, 42271-23-8; CH3Registry No. 7,123170-38-7; 8,123170-39-8; 9,123170-40-1; Hz0CH2CH20Na,34074-45-8; C(CH,OH),, 77-85-0; CH3(CH3OCHz)CCH2OCH2OCH2, 6252910,123170-41-2; lla,78353-64-7; llb,78362-40-0; 12a,123170-650; 15-1;CH3S03H, 75-75-2; CH3SO2C1,124-63-0; Br(CH2)30CH12b,123170-66-1; 12~, 123170-67-2; 13,123170-68-3; 14,123170(OEt)CH3, 34399-67-2; CO, 630-08-0; PhLi, 591-51-5; MeLi, 69-4;15, 123170-70-7; 16, 123170-71-8; 17, 123170-72-9;18, 917-54-4; Et2NLi, 816-43-3; 'PrzNLi, 4111-54-0; Me30+BF~, 78353-59-0; 19,123170-73-0; 20,123170-74-1; 21,123170-75-2; 22, Me3SiC1, 75-77-4; [Mo(CO),(PhCOLi)], 60490-49-5; 123170-76-3; 23,123170-77-4; 24,123170-78-5; 25a,78353-57-8; 420-37-1; [PhC=O]-, 78944-74-8; diethylene glycol, 25b,78353-58-9;25~, ~53-56-7; 26a,7~2-39-7; 26c,1~3170-79-6; [ MeC=O]-, 3170-69-2; bis(2-hydroxyethyl)methylamine,105-59-9; 3-oxa-l,627,123170-80-9; 28,123170-81-0; 29,78379-71-2; 30,123170-82-1; 111-46-6; N-(2-hydroxyethyl)-N-(3-hydroxypropyl)31a,78353-65-8; 31b,78362-42-2; 32,78362-44-4; 33a,85421-20-1; hexanediol, 929-28-2; methylamine, 106694-59-1; 4-oxa-1,7-heptanediol, 2396-61-4; 33b, 123170-83-2;33c, 123170-84-3; 34a, 78353-61-4;34b, N,N-bis(3-hydroxypropyl)methylamine,2158-67-0; N,N-bis(378353-62-5; 35,123170-85-4; 36,123170-86-5; 37,78353-60-3; 39a, 123170-88-7; 39b,123170-87-6; 41a,123170-89-8;41b,123170-90-1; hydroxypropyl)isopropylamine, 34753-59-8;N-(2-hydroxyN-(2-hydroxy41~, 123170-91-2; 42,123170-92-3; 43,123170-93-4; 44,123170-94-5; ethyl)-2-(2-hydroxyethyl)piperidine,84681-78-7; N-(3-hydroxy45,123170-95-6; 46,123170-96-7; 47,78362-48-8; 48,123170-97-8; ethyl)-3-(hydroxymethyl)piperidine,94231-64-8; 49,123170-98-9; 50,123170-99-0; 51,123171-00-6; 52,123171-01-7; propyl)-3-(hydroxymethyl)piperidine, 106694-61-5;N-(3hydroxypropyl)-2-(2-hydroxyethyl)piperidine,106694-60-4; 3,753,123171-288; 54a, 78353-63-6; 54b,91582-42-2; 54~, 123171-02-8; tetraethylene glycol, 112-60-7; 55a,78362-46-6; 55c, 123171-03-9; 56,123171-04-0;57,123171-051; dioxa-1,9-nonanediol,67439-82-1; 123030-36-4; pentaethylene glycol, 58,78362-47-7; 59,123171-06-2; 60a,85421-22-3; 61,123171-07-3; 3,6-dioxa-1,9-nonanediol, 1,3-propanediol, 54481-30-0; 1,3-propanediyl bis(to1u62,123171-08-4; 63,123171-09-5; 64,123171-10-8; 65,123171-11-9; 4792-15-8; enesulfonate), 5469-66-9; tris(hydroxymethyl)ethane, 77-85-0; 66a, 123171-12-0; 66b,123171-13-1; 66c, 123171-14-2;67a, 2,4-dinitrophenylhydrazine, 119123171-15-3; 6 7 ~123171-16-4; , 68,123171-17-5; 69,123171-18-6; paraformaldehyde, 30525-89-4; ethylene oxide, 70,123171-19-7; 71,123171-20-0; 72,123171-21-1; 73a,123171-22-2; 26-6;N,"-dimethyl-l,2-diaminoethane, 110-70-3; 75-21-8;N,N'-dimethyl-1,3-diaminopropane,111-33-1;iso74a, 123171-23-3; 74b, 123171-24-4; 75a, 123171-25-5; 75b, propylamine, 75-31-0; N-(3-hydroxypropyl)bemylamine,4720-29-0 123188-15-8;77, 123171-26-6;78, 123171-27-7;Ph2PO2-methoxyethylamine, 109-85-3; 2-(2-hydroxyethyl)piperidine, (CH2)2NMe(CH2)zOPPh2,123188-13-6; PhzPO(CH2)zNiPr1484-84-0;3-(hydroxymethyl)piperidine,4606-659; p-tolyllithium, (CH2)20PPh2, 123170-42-3;Ph2PO(CH2)20(CH2)30PPhZ, triethylene glycol, 112-27-6; 40,65991-64-2. 123170-43-4;Ph2PO(CH2)2NMe(CH2)30PPh2, 123170-44-5; 2417-95-0;

Acknowledgment. We thank the Natural Science and Engineering Research Council of Canada for financial support.

Synthesis and chemistry of chelating phosphinite complexes of Group

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