Ruthenium polymerisation catalysts

Abstract

Cis and trans ruthenium complexes that can be used as catalysts for ring opening metathesis polymerization (ROMP) are described. The complexes are generally square pyramidal in nature, having two anionic ligands X. Corresponding cationic complexes where one or both of the anionic ligands X are replaced by a non-co-ordinating anionic ligand are also described. Polymers such as polydicyclopentadiene (PDCPD) can be prepared using the catalysts.

Claims

1. A method of catalyzing a ring-opening metathesis polymerization (ROMP) reaction comprising: providing a reactant having at least two olefin and/or alkyne functional groups; providing a cis ruthenium complex according to formula I: ##STR00155## wherein for each occurrence the groups X are the same or different and are anionic ligands or are fused to form a bidentate ligand; the groups R.sup.1 and R.sup.2 are fused together to form an indenylidene ring that may be substituted or unsubstituted; and the group Z is selected from the group consisting of: ##STR00156## wherein the groups R.sup.3, R.sup.4 and R.sup.5 are each independently for each occurrence selected from the group consisting of substituted or unsubstituted primary, secondary or tertiary alkyl, that may be cyclic and may be unsaturated; substituted or unsubstituted aryl or heteroaryl; and optionally two or more of the groups R.sup.3, R.sup.4 and R.sup.5 are fused to form a ring; the group A is selected from the group consisting of a N-heterocyclic carbine (NHC) and contacting the reactant with the cis ruthenium complex according to formula I for a time and at a temperature capable of causing ring-opening metathesis polymerization (ROMP).

2. The method according to claim 1 wherein the group Z is a phosphite: ##STR00157##

3. The method according to claim 1 wherein the anionic ligands X are independently selected from the group consisting of halogen, benzoate, and C.sub.1-C.sub.5 carboxylates.

4. The method according to claim 1 wherein the group A is an N-heterocyclic carbene selected from the group consisting of: ##STR00158##

5. The method according to claim 1 wherein the ruthenium complex is: ##STR00159##

6. The method according to claim 1 wherein the ruthenium complex is according to formula XI: ##STR00160## wherein the substituent Rs is selected from the group consisting of: OMe, CF.sub.3, Cl, NO.sub.2 and SF.sub.5.

7. A ruthenium complex of the formula: ##STR00161##

8. A ruthenium complex of the formula XI: ##STR00162## wherein the substituent Rs is selected from the group consisting of: OMe, CF.sub.3, Cl, NO.sub.2 and SF.sub.5.

9. A ruthenium complex of the formula: ##STR00163##

10. A ruthenium complex of the formula: ##STR00164##

11. The method according to claim 1 wherein the anionic ligands X are independently selected from the group consisting pivalate, trifluoroacetate, C.sub.1-C.sub.5 alkoxy, phenoxy, C.sub.1-C.sub.5 alkyl thio, tosylate, mesylate, brosylate, trifluoromethane sulfonate, phenylacetate, and pseudo-halogen.

12. A method of catalyzing a metathesis reaction comprising: introducing at least one olefin and/or alkyne functional group; providing a cis ruthenium complex according to formula I: ##STR00165## wherein for each occurrence the groups X are the same or different and are anionic ligands or are fused to form a bidentate ligand; the groups R.sup.1 and R.sup.2 are fused together to form a substituted or unsubstituted indenylidene moiety that may be fused to a further ring; and the group Z is selected from the group consisting of: ##STR00166## wherein the groups R.sup.3, R.sup.4 and R.sup.5 are each independently for each occurrence selected from the group consisting of substituted or unsubstituted primary, secondary or tertiary alkyl, that may be cyclic and may be unsaturated; substituted or unsubstituted aryl or heteroaryl; and optionally, two or more of the groups R.sup.3, R.sup.4 and R.sup.5 are fused to form a ring; the group A is a N-heterocyclic carbene; and contacting the reactant with the cis ruthenium complex according to formula I, for a time and at a temperature capable of causing metathesis polymerization.

13. A method of catalyzing a ring-opening metathesis polymerization (ROMP) reaction comprising: providing a reactant having at least two olefin and/or alkyne functional groups; providing a ruthenium complex according to the formula: ##STR00167##  and contacting the reactant with the ruthenium complex for a time and at a temperature capable of causing ring-opening metathesis polymerization (ROMP).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the present invention will appear from the following detailed description of some embodiments illustrated with reference to the accompanying drawings in which:

(2) FIGS. 1a to 1d show X-ray structures of complexes of the invention;

(3) FIG. 2 shows graphically trans to cis isomerisation of complexes of the invention;

(4) FIG. 3 shows graphically trans to cis isomerisation of complexes of the invention; and

(5) FIG. 4 shows graphically results of ring closure metathesis experiments using various catalysts.

DESCRIPTION OF SOME PREFERRED EMBODIMENTS AND EXPERIMENTAL RESULTS

(6) Preparation of Complexes of Formulas I and II Including an NHC

(7) ##STR00035##

(8) A general procedure is to react complex 1 of scheme 2 above with different groups Z, phosphites in these examples. Phosphites (1-4 equiv) in dichloromethane were reacted with 1 and stirred for 3-15 h at 60° C. This procedure led, whatever the phosphite employed was, to a mixture of two new complexes, presenting .sup.31P NMR shifts corresponding to coordinated phosphites—between 110 and 135 ppm whereas free phosphites are around 128-145 ppm.

(9) Where the phosphite ligand was P(OiPr).sub.3, as shown in Scheme 2 the conditions described above allow a 90% pure complex (.sup.31P NMR in CDCl.sub.3, major: δ=113 ppm, minor: δ=123 ppm), to be isolated as a red powder. NMR experiments in d.sub.8-toluene showed that, after 1 h at 80° C., the complex presenting a chemical shift at 113 ppm was highly converted into the one at 123 ppm. The latter complex was thus isolated and characterized.

(10) .sup.1H NMR of the two complexes showed interesting differences on the phosphite alkoxy groups. Indeed, nicely resolved doublets corresponding to the six equivalent terminal methyl groups of the isopropyl groups in the first complex were found inequivalent in the latter complex, indicating that the free rotation of the phosphite was no longer possible. In addition, .sup.13C NMR experiments were conducted to observe, in both complexes, the J coupling between the NHC carbenic carbon and the phosphite phosphorus. While the firstly generated complex (.sup.31P, δ=113 ppm) displayed a carbenic carbon at 208.9 ppm with a classical coupling constant J.sub.C-P=124 Hz, the second complex (.sup.31P, δ=127 ppm) displayed an unusual small coupling of 13 Hz. These observations led to the conclusion that complex trans-2, featuring a trans configuration between the NHC and the phosphite, was obtained kinetically while cis-2 was thermodynamically favored (scheme 2). Complex cis-2 could also be isolated on a larger scale in a good yield of 86% by heating trans-2 in chloroform at 60° C. for 5 h. Interestingly, aspect and solubility were completely different for trans-2 and cis-2. Indeed, while trans-2 was isolated as a red powder that is soluble in polar and apolar solvents, cis-2 is a black solid completely insoluble in pentane, indicating a dependence of physical properties to spatial arrangement. The structure of cis-2 has been confirmed by X-ray crystallography, following growth of a suitable crystal from CH.sub.2Cl.sub.2/n-dodecane. (See FIG. 1b). The X-ray data also show that the complex cis-2 is present as a pair of enantiomers as discussed above.

(11) In order to obtain cis-complexes directly, with different phosphite ligands, 1 and a selected phosphite were stirred at 40° C. in dichloromethane for the appropriate time (Table 1, below). Following the reaction by .sup.1H and .sup.31P NMR furnished showed different conversion rates. As a general trend, reactivity was dependent on the cone angle of the phosphite. Indeed, the reaction was found to be slower with bulky phosphites such as P(OiPr).sub.3 and P(OPh).sub.3, (15 h), while smaller phosphites such as P(OMe).sub.3 required only 3 h at 40° C. For P(OPh).sub.3, 4 equiv of P(OPh).sub.3 were necessary to obtain relatively fast conversion to the desired complex. With these conditions, complexes cis-2-5 (Table 1) were isolated in yields up to 88%, For cis-3 the lower yield was due to purification difficulties. X ray structures of cis-4, cis-2, cis-3 and cis-5 are shown in FIGS. 1a to 1d respectively.

(12) TABLE-US-00001 TABLE 1 Synthesis of cis-Ru-Phosohite complexes.sup.a P(OR).sub.3 θ [Ru] Yield Entry (equiv) (°).sup.b complex Time (%) 1 P(OMe).sub.3 (1) 107 cis-3  3 h 57 2 P(OEt).sub.3 (1) 109 cis-4  5 h 88 3 P(OiPr).sub.3 (1) 128 cis-2 15 h 84 4 P(OPh).sub.3 (4) 130 cis-5 15 h 76 .sup.aReaction conditions: 1 (1 equiv), phosphite, CH.sub.2Cl.sub.2, 40° C. .sup.bTolman cone angle.

(13) NMR studies in CD.sub.3NO.sub.2 and toluene-d.sub.8 (FIGS. 2 and 3 respectively) show the thermal conversion from trans to cis of a sample that contained 90% trans: 10% cis complex 2.

(14) ##STR00036##

(15) All the experiments shown were followed by NMR starting from the trans-2 complex complex (pure at 90%, with 10% of cis isomer), except in toluene one experiment at 50° C. started from the pure cis-2. As we can see, polar solvents (nitromethane) favored the formation of the cis isomer whereas apolar solvent (toluene) reached an equilibrium cis/trans 80:20. It seems that a temperature of 30° C. is too low to allow fast conversion. Starting from the cis isomer and heating in toluene led also to a mixture cis/trans 80:20. The first set of curves allowed the calculation of ΔH=22.6 kcal/mol and ΔS=−4.2 cal/mol.

(16) A further example of a synthesis producing an NHC containing cis complex is shown below.

(17) ##STR00037##

(18) HII (200 mg) and P(O.sup.iPr).sub.3 (5 eq) were stirred in for 72 h. The crude 65 was recrystallised from DCM/pentane.

(19) .sup.1H (400 MHz, 298K): 16.05 (d, 1H, J=35.3 Hz, C═CH), 10.24 (d, 1H, J=9.7 Hz, Ph-H), 6.87-6.83 (m, 2H, Ph-H), 6.78 (s, 1H, Ph-H), 6.61 (s, 1H, Ph-H), 6.19-6.16 (m, 2H, Ph-H), 4.67 (brs, 2H, PO—CH—CH.sub.3), 4.09-4.06 (m, 1H, Ph-O—CH—CH.sub.3), 4.04 (brs, 1H, PO—CH—CH.sub.3), 3.43-3.40 (m, 1H), 3.16-3.02 (m, 3H), 2.89 (s, 3H, Mes-CH.sub.3), 2.58 (s, 3H, CH.sub.3), 2.46 (s, 3H, CH.sub.3), 2.42 (s, 3H, CH.sub.3), 2.18 (s, 3H, CH.sub.3), 1.92 (s, 3H, CH.sub.3), 1.48-0.80 (m, 24H, PO—CH—CH.sub.3).

(20) .sup.31P{.sup.1H} (121.49 MHz, 298K): 128.7 (s)

(21) Catalytic Activity of Complexes of Formulas I and II

(22) Catalytic activity of complexes was evaluated in ring closing metathesis (RCM), enyne ring closing metathesis (enyne RCM) and cross metathesis (CM). The difference of behavior between trans-2 and cis-2 was studied. The main difference appeared when reactions were run at room temperature. Indeed, whereas trans-2 was able to achieve RCM of diallyltosylamine 6, albeit with lower activities compared to previously reported indenylidene ruthenium complexes, cis-2 was found to be totally inactive at room temperature, even after 24 hours of reaction (Table 2, below, entry 1). Nevertheless, with the same substrate, thermal activation at 80° C. in toluene allowed fast conversion in the presence of cis-2. The same trend was observed in RCM with diallyllic malonate 8, in enyne RCM with 10 and CM with alkene 12 (Table 2, entries 2-4), trans-2 being active at rt while cis-2 needed thermal activation. Such behavior corresponds to a latent catalyst. In order to evaluate the thermal stimulation needed to activate cis-2, RCM of 6 was monitored at different temperatures (25, 40, 60 and 80° C.), the temperature being changed every 30 minutes. No conversion was observed at room temperature and 40° C., 4% conversion at 60° C., and full conversion at 80° C. As a consequence, the comparative study of complexes cis-2 to 5 was conducted at 80° C.

(23) In Table 2 below results for known complexes M2 (scheme 1) and 1 (pyridine containing complex of scheme 2) are also shown for comparison purposes.

(24) TABLE-US-00002 TABLE 2 Behaviour of trans-2 vs cis-2..sup.a catalyst T t conv. Entry Substrate Product [mol %] [° C. ] [h] [%].sup.b 1 trans-2 (1)   cis-2 (1) rt   rt 40 60 80  5 24 24   0.5   0.5   0.5 18 88  0  0  4 >99   2 0 1 (1) M2 (1) trans-2 (1) cis-2 (1) rt rt rt rt 80  5  5  5 24   0.5 38 82 80  0 >99   3 1 (1) M2 (1) trans-2 (1) cis-2 (1) rt rt rt rt 80 24 24 24 24   0.5 12 63 52  0 >99   4 trans-2 (2) cis-2 (2) cis-2 (2) rt rt 80  8  8   0.5    1.75 65  0 90 97 .sup.aReaction conditions: substrate (0.25 mmol), catalyst (1-2 mol %), solvent (0.1M, CH.sub.2Cl.sub.2 and toluene for reactions respectively at room temperature and 80° C.). .sup.bAverage of 2 runs; conversions were determined by .sup.1H NMR.

(25) Complexes were studied as catalysts in RCM of diene, enyne and in CM (Table 3 below). Known complexes 1 (pyridine containing complex of scheme 2, known as M31), M1 and M2 (scheme 1) were also included in some experiments for comparison purposes.

(26) ##STR00046##

(27) These complexes are available from Umicore N.V.; Broekstraat 31 rue du Marais B-1000 Brussels, Belgium.

(28) A general trend was found between reactivity and the phosphite substituent for the new complexes. Triisopropyl phosphite and triphenyl phosphite-containing complexes cis-2 and 5 were found to have comparable efficiency, the former one being slightly more active. Indeed, after 30 minutes, RCM of 8 was achieved with cis-2 while traces of 8 could still be detected with cis-5. Even clearer evidences were provided with reactions of 10 and 12, cis-2 being faster than cis-5. Finally, cis-3 and 4, featuring respectively trimethyl and triethylphosphite were similar but far less reactive than cis-2 and 5. Very slow reactivity was observed in the reactions tested, even if a longer reaction time could probably reach full conversion. In order to explore the applicability of such catalysts in metathesis transformations, we chose to run reactions with catalyst cis-2 and at elevated temperature.

(29) TABLE-US-00003 TABLE 3 Behaviour of cis-2-5..sup.a catalyst T t conv. Entry Substrate Product [mol %] [° C. ] [h] [%].sup.b 1 cis-2 (1) cis-3 (1)   cis-4 (1)   cis-5 (1)   1 (0.5) M1 (0.5) M2 (0.5) trans-2 (0.5) 80 80   80   80   80 80 80 80 0.5 0.5 1 0.5 1 0.5 1 0.5 0.5 0.5 0.5 >99   78 >99   35 73 98 >99   >99   >99   >99   >99   2 0 cis-2 (0.5) cis-3 (0.5) cis-4 (0.5) cis-5 (0.5) 80   80   80   80 0.5 1.75 1.75   1.75   1.75 72 >99    5   10   91 3 cis-2 (2)   cis-3 (2)   cis-4 (2)   cis-5 (2) 80   80   80   80 0.5 1.75 0.5 1.75 0.5 1.75 0.5 1.75 90 97  6 38 13 67 60 94 .sup.aReaction conditions: substrate (0.25 mmol), catalyst (0.5 to 2 mol %), toluene (0.1M), 80° C. .sup.bConversions were determined by .sup.1H NMR.

(30) A study of the RCM of several substrates has also been carried out. Reactions were run in toluene at 80° C. in the presence of 1 to 5 mol % of cis-2, the higher catalyst loading being only necessary for the formation 17 featuring a tetra-substituted double bond (Table 4 below, entry 3). The RCM of unhindered malonate derivatives was achieved in short reaction times (less than 1 hour) and in good yields. Indeed, di- and tri-substituted cyclopentenes 15 and 9 were obtained in quantitative yields (entries 1 & 2). Nevertheless, highly constrained substrate 16 could not be cyclized with full conversion, even after 24 h at 80° C., and was isolated in 70% yield (entry 3). Finally, b- and 7-membered rings 19 and 21 were obtained in respectively 96 and 87% yield, and no increase in reaction time compared to 5-membered ring 15 (entries 4 & 5). Of note, a dilution to 0.05M was necessary to obtain 21 without observing parallel formation of polymers. We next attempted the RCM of cyano analogues 24 and 26 (entries 6 & 7). Non-hindered cyclopentene 23 was isolated in good yield (88%), indicating that the presence of potentially chelating cyano groups was not detrimental to catalysis. Nevertheless, cis-2 was unable to promote the formation of 25, the starting material remaining unreacted. Tosylamine-based olefins were next investigated. The cyclization of these compounds was found very efficient regardless of hindrance and ring size. Indeed, 5-, 6- and 7-membered compounds 7, 27 and 29 were isolated in excellent yields (entries 8-10), albeit a slight increase in reaction time was needed for larger rings. Catalyst loading of only 2 mol % was necessary to achieve the cyclizations of 30 and 32 to obtain tetrasubstituted 5- and 6-membered rings 31 and 33 in good yields (entries 11 & 12), even so 5 hours of reaction were needed for dihydropyrrole 31. Amide and ether-based substrates were also efficiently cyclized, with yields spanning from 80% to 99% (entries 13-17). Increasing the ring size to 6 or 7 members was not detrimental, as products 39, 41 and 43 were obtained excellent yields in less than 1 hour (entries 15-17). From this study, catalyst cis-2 seemed to be highly tolerant to functionalities and able to effect RCM easily.

(31) This utility of the complexes of the invention is illustrated further in FIG. 4 which shows RCM of compound 30 (table 4 entry 11) in toluene at 80° C. carried out with a range of Ru complexes. Trans or cis-2 both rapidly produce a high conversion whereas prior art complexes Hov-II, M2 (structures shown in Scheme 1) and M31 (which is the pyridine complex 1 in scheme 2) did not produce any better than about 60% conversion (complex M2) under these conditions.

(32) TABLE-US-00004 TABLE 4 Ring closing metathesis behavior of cis-2.sup.a t conv. Entry Substrate Product [h] [%].sup.b  1 0.5 >99   (99)  2 0.5 >99   (99) .sup.   3.sup.c 24 82 (70)  4 0 0.5 >99   (96)   5.sup.d 1 >99   (87)  6 0.5 >99   (88) .sup.   7.sup.c 24  0  8 0.5 >99   (97)  9 0 1.25 >99   (99) 10 1 >99   (88)   11.sup.e 5 >99   (95) .sup.  12.sup.e 1.5 >99   (99) 13 0.5 >99   (99) 14 0 0.75 >99   (80) 15 0.75 >99   (99) 16 0.5 >99   (94)  17.sup.d 0.75 >99   (99) .sup.aReaction conditions: substrate (0.25 mmol); cis-2 (1 mol %), toluene (0.1M), 80° C. .sup.bAverage of 2 runs; conversions were determined by NMR; isolated yields are in brackets. .sup.c5 mol % of catalyst were used. .sup.d0.05M concentration was used. .sup.e2 mol % of catalyst were used.

(33) Enyne ring closing metathesis is a powerful tool to synthesize dienes that can undergo further Diels-Alder reaction and thus furnish bicyclic compounds readily. Easy substrates 10 and 44 were fully converted after 30 minutes, albeit 11 was only isolated in 75% yield (Table 5 below, entries 1 & 2). A longer reaction time was necessary to convert hindered compound 46 (entry 3). Once again, a relatively low isolated yield of 71% (compared to 99% conversion) was obtained; such behaviour could result from parallel polymerization reactions that can easily occur at elevated temperature. While substrate 48 remained unchanged after 24 h of reaction, the more hindered enyne 50 was efficiently cyclized in 3 h (entries 4 & 5). Addition of ethylene is known to be necessary to allow reaction in the case of terminal alkynes such as 48. In conclusion, catalyst cis-2 allowed the formation of dienes from enynes in a short reaction time and acceptable yields.

(34) TABLE-US-00005 TABLE 5 Enyne ring closing metathesis behaviour of cis-2.sup.a t conv. Entry Substrate Product [h] [%].sup.b 1 0.5 >99   (75) 2 0 0.5 >99   (99) .sup.  3.sup.c 19 >99   (71) 4 24  0 5 3 >99   (81) .sup.aReaction conditions: substrate (0.25 mmol), cis-2 (1 mol %), toluene (0.1M), 80° C. .sup.bAverage of 2 runs; conversions were determined by NMR; isolated yields are in brackets. .sup.c5 mol % of catalyst were used.

(35) The ability of catalyst cis-2 to promote intermolecular cross metathesis has also been investigated (Table 6 below). CM reactions are more difficult than their RCM counterparts as side-formation of self-metathesis products may happen. Several substrates were put in presence of 2 mol % of cis-2, together with 2 equivalents of alkene partners in toluene at 80° C. Silylated compound 12 was efficiently coupled with various olefins (entries 1-4). Indeed, the use of methyl acrylate, acrofein and diallylic acetate as alkene partners allowed the isolation of the desired products, respectively 13, 52 and 54, in good yields compared to previously reported results, thus proving that cis-2 has a good tolerance toward functional groups (entries 1, 2 and 4). However, allyltosylamine was found incompatible with our catalytic system as no conversion to 53 was observed (entry 3). Ester-containing substrates 55 and 57 bearing different chain lengths were also coupled with methylacrylate in good yields (entries 5 & 6). Both products were isolated as E isomers, the Z ones not being detected by .sup.1H NMR. Reaction of eugenol 59 (essential oil of clove) with acrolein was found efficient and did not need protection of its phenolic moiety (entry 7). Finally, p-chlorostyrene 61 reacted well with methyl acrylate and gave 62 in 81% yield with an E/Z ratio of 20:1. No formation of self-metathesis compounds was observed during the testing of these substrates.

(36) TABLE-US-00006 TABLE 6 Cross metathesis behaviour of cis-2.sup.a Yield Alkene t [%] Entry Substrate partner Product [h] (E/Z).sup.b 1 2 81 (>20:1) 2 00 01 2 57 (>20:1) 3 02 03 3.5  0 .sup.  4.sup.c 04 05 3.5 59 (6:1) 5 06 07 08 2.5 85 (>20:1) 6 09 0 2.5 75 (>20:1) 7 5 62 (6:1) 8 3 81 (>20:1) .sup.aReaction conditions: substrate (0.25 mmol), alkene partner (0.5 mmol), cis-2 (2 mol %), toluene (0.1M), 80° C. .sup.bAverage of 2 runs; isolated yields; E/Z ratios were determined by .sup.1H NMR. .sup.cOnly 1 equiv of alkene partner was used.
Preparation of Complexes of Formulas VIII and X

Formula VIII Example

(37) ##STR00117##

(38) The complex cis-2 was reacted at room temperature with one equivalent of silver hexafluoroantimonate, yielding the pure complex 63, after simple removal of salts by filtration on celite.

(39) .sup.13C{.sup.1H} NMR spectrum of 63 displayed a coupling constant between the carbene carbon atom and the phosphite ligand .sup.2J.sub.C-P of 15.1 Hz, consistent with a cis-configuration between the NHC and the phosphite ligands. This value is very similar to the one found for cis-2 (13.4 Hz) and very far from the one found for trans-2 (127.8 Hz). Similarly, the .sup.2J.sub.C-P between the indenylidene carbon atom C.sup.1 and the phosphorus atom of 63 (23.2 Hz) was also found very similar with the 24.7 Hz obtained with cis-2 (trans-2 31.0 Hz).

(40) The structure of 63 was confirmed by X-ray crystallography.

(41) Complex 63 may be converted into an acetonitrile containing species 63a as below:

(42) ##STR00118##

(43) In a glove box, 63 (77.0 mg, 0.071 mmol) was dissolved in 1 mL of acetonitrile and the mixture was stirred for fifteen minutes. Solvent was removed in vacuo. The black solid was washed with hexane yielding 63a (99%).

(44) .sup.1H NMR (CD.sub.2Cl.sub.2, 400 MHz): δ (ppm)=1.13 (d, .sup.3J.sub.HH=5.6 Hz, 9H, CH—CH.sub.3), 1.17 (d, .sup.3H.sub.HH=5.6 Hz, 9H, CH—CH.sub.3), 2.02 (s, 6H, mesityl CH.sub.3), 2.06 (s, 3H, CH.sub.3), 2.16 (s, 6H, mesityl CH.sub.3), 2.34 (s, 6H, mesityl CH.sub.3), 4.01 (s, 4H, carbene CH.sub.2), 4.31 (s br, 3H, CH—CH.sub.3), 6.32 (s, 1H, indenylidene H), 6.74 (s, 2H, mesityl CH), 6.87 (s, 2H, mesityl CH), 7.32 (d, .sup.3J.sub.HH=8.0 Hz, 1H, indenylidene H), 7.41-7.50 (m, 4H, indenylidene), 7.59 (t br, .sup.3J.sub.HH=7.3 Hz, 1H, indenylidene H), 7.63 (d br, .sup.3J.sub.HH=7.3 Hz, 2H, indenylidene H), 7.83 (s, 1H, indenylidene H).

(45) .sup.31P{.sup.1H} NMR (CD.sub.2Cl.sub.2, 162 MHz) δ (ppm)=115.5

(46) The catalytic potential of 63 was first assessed for the RCM (ring closing metathesis) of the challenging tosylamine derivative 30 (Table 7) at a low catalyst loading (0.1 mol % Ru).

(47) At 80° C., all solvents gave no or very poor conversions (Table 7, entries 1-3). Reactions carried out in xylene or mesitylene at temperatures above 110° C. (120-140° C.) gave product 31 with good conversions (76-79%) (Table 7, entries 4, 5, 9, 10). Increasing the temperature to 160° C. lead to a lower conversion to product (Table 7, entry 11). When neat conditions were used, conversion fell to 60% (Table 7 below, entry 7). Dimethyl sulfoxide or 1,2-dichlorobenzene were also found to be highly prejudicial to the reaction with a dramatic decrease of the conversion rate (Table 7, entries 6, 8).

(48) TABLE-US-00007 TABLE 7 Optimization of reaction conditions. Entry Solvent T[° C.] Conv. [%].sup.[b] 1 toluene 80 7 2 acetonitrile 80 0 3 iso-propanol 80 1 4 xylene 120 76 5 xylene 130 77 6 dimethyl sulfoxide 140 0 7 neat 140 60 8 1,2- 140 50 dichlorobenzene 9 mesitylene 140 77 10 xylene 140 79 11 mesitylene 160 69 [a] Reaction conditions: 30 (0.25 mmol), 63 (0.1 mol % Ru), solvent (1 mL), 3 h. .sup.[b]Average of 2 runs; conversions determined by GC.

(49) Under the optimized reaction conditions (entry 10 of Table 7), the kinetic profile of 63 was recorded and compared to that of its parent neutral complex cis-2 (FIG. 5). At 140° C., cis-2 exhibits a very fast initiation and a high activity for only 3 minutes. Decomposition of the cis-2 occurred rapidly and the catalyst could not achieve more than 60% of conversion. Better results were obtained in table 4 (entry 11 above) where more catalyst and a longer reaction time was employed. In contrast, a thermal treatment of 3 minutes at 140° C. was found necessary to activate 63 indicating it can be considered a latent catalyst, which then achieved 80% conversion within 10 minutes. This shows that 63 is more thermally stable than cis-2.

(50) The catalytic potential of 63 was than investigated for a range of dienes and enynes, under these harsh reaction conditions: 140° C., 15 min (Table 8).

(51) TABLE-US-00008 TABLE 8 Metathesis reactions behavior of 63. 0 30 6 26 32 14 8 18 16 10 64 0 66 Conversion (isolated Entry Substrate product. Cat. (mol %) yield).sup.[b] 1 0.1 99 (90) 2 0.1 99 (97) 3 0.1 91 (85) 4 0.2 90 (89) 5 0 0.2 99 (96) 6 0.1 99(92) 7 0.1 99(95) 8 2 51 9 10 0.2 99(79) 10 64 (1 eq.) 66 (2 eq.) 0.4 81(72) [a] Reaction conditions: 63 (0.1-2 mol %), substrate (0.25 mmol), xylene (1 mL), 15 min, 140° C. .sup.[b]Average of 2 runs; conversions were determined by GC; selected isolated yields in brackets.

Formula X Example

(52) ##STR00149##

(53) In a glove box, Ru complex cis-2 (0.150 g, 0.171 mmol) and silver hexafluoroantimonate (0.130 g, 0.366 mmol) and dichloromethane (5 mL) were charged in a dry flask. The reaction mixture was stirred for fifteen minutes and the solution was filtered through a plug of celite. After evaporation of solvent, pentane was added and the precipitate was collected by filtration and washed with pentane. 67 was obtained as a black greenish solid in 95% (0.1990 mg). The structure of 67 was ultimately determined by X-ray crystallography, demonstrating that a chloride had been retained and the Ru had therefore been oxidized to the III state, presumably by Ag(I) being reduced to Ag(0).

Other Examples of Complexes of Formulas I and II

(54) A cis complex 68 comprising a phosphine and a phosphite as ligands A and Z can be made as follows:

(55) ##STR00150##

(56) Under an inert atmosphere, triisopropylphosphite (364 μL, 1.53 mmol) was added to a solution of M1 (1.4145 g, 1.53 mmol), in dichloromethane (20 mL). The mixture was stirred for 24 h at room temperature, then the solvent was removed in vacuo. The crude was recrystallised from CH.sub.2Cl.sub.2/pentane. The solid was collected by filtration and washed with pentane (3×10, 2×15 mL). The product 68 was obtained as a brownish red solid (1.116 g, 85% yield).

(57) .sup.1H-NMR (400 MHz, 298K): δ (ppm)=1.10-1.35 (m, 27H), 1.40-1.55 (m, 6H), 1.60-1.85 (m, 14H), 6.79 (s, 1H, indenylidene H), 7.27 (d, J=7.1 Hz, 1H, indenylidene H), 7.43 (dd, J=6.7 Hz, J=6.3 Hz, 1H, indenylidene), 7.44 (dd, J=7.4 Hz, J=6.3 Hz, 2H, indenylidene), 7.50 (dd, J=7.4 Hz, J=7.7 Hz, 1H, indenylidene), 7.53 (dd, J=7.4 Hz, J=7.4 Hz, 1H, indenylidene), 7.76 (d, .sup.3J.sub.HH=7.3 Hz, 2H, indenylidene), 8.80 (d, J=7.3 Hz, 1H, indenylidene).

(58) .sup.31P-{.sup.1H}-NMR (162 MHz, 298K): δ (ppm) 120.1 (d, J=37.0 Hz), 47.4 (d, J=37.0 Hz).

(59) Following a similar procedure, with more phosphite reagent, the cis bis-phosphite complex 69 can be obtained.

(60) ##STR00151##

(61) .sup.31P-{.sup.1H}-NMR (CD.sub.2Cl.sub.2, 162 MHz): δ (ppm)=122.9.

Further Examples of the Synthesis of Complexes and Use of the Catalysts in ROMP

(62) Complex 1 (also known as M31) of scheme 2 was reacted with further phosphite ligands as shown below.

(63) ##STR00152##

(64) The cis complexes 70a to 70e feature various para substituents on the phenyl rings of the phosphite ligands. These variations in the phosphite ligand can be employed to adjust catalytic activity.

(65) The general procedure employed in manufacture was as follows:

(66) A Schlenk flask was charged with [RuCl.sub.2(Ind)(Py)(SIMes)] (M31) (0.5 g, 0.668 mmol), the corresponding phosphite (0.801 mmol, 1.2 eq) and dichloromethane (8 mL). The reaction was stirred at 40° C. during 15 hours, concentrated in vacuo and pentane was added. The precipitate was collected by filtration and washed with pentane.

Dichloro-{N,N′-bis[2,4,6-(trimethyl)phenyl]imidazolin-2-ylidene}Indenylidene)(p-methoxyphenylphosphite) ruthenium (70a)

(67) Using 500 mg of M31 (0.668 mmol), the procedure afforded 479 mg (67%) of the product.

(68) .sup.1H NMR (CD.sub.2Cl.sub.2, 300 MHz, 233K): δ (ppm)=1.47 (s, 3H, CH.sub.3), 1.90 (s, 3H, CH.sub.3), 2.11 (s, 3H, CH.sub.3), 2.41 (s, 3H, CH.sub.3), 2.62 (s, 3H, CH.sub.3), 2.75 (s, 3H, CH.sub.3), 3.04 (s, 3H, O-Me), 3.65 (s, 3H, O-Me), 3.88 (s, 3H, O-Me), 3.68-4.02 (m, 4H), 5.62 (d, J=9.1 Hz, 2H), 6.05 (s, 1H), 6.10 (d, J=8.8 Hz, 2H), 6.18 (s, 2H), 6.39 (d, J=8.8 Hz, 2H), 6.57 (d, J=9.12 Hz, 2H), 6.93 (d, J=6.9 Hz, 2H), 7.08 (d, J=9.2 Hz, 3H), 7.22 (t, J=7.2 Hz, 1H), 7.33 (s, 1H), 7.26-7.39 (m, 4H), 7.42-7.49 (m, 3H), 8.61 (d, J=7.8 Hz, 1H). .sup.31P-{.sup.1H} NMR (CD.sub.2Cl.sub.2, 162 MHz, 298K): δ (ppm)=116.1.

Dichloro-{N,N′-bis[2,4,6-(trimethyl)phenyl]imidazolin-2-ylidene}Indenylidene)(p-trifluoromethylphenylphosphite) ruthenium (70b)

(69) Using 500 mg of M31 (0.668 mmol), the procedure afforded 479 mg (61%) of the product.

(70) .sup.1H NMR (CD.sub.2Cl.sub.2, 300 MHz, 233K): δ (ppm)=1.50 (s, 3H, CH.sub.3), 1.95 (s, 3H, CH.sub.3), 2.09 (s, 3H, CH.sub.3), 2.42 (s, 3H, CH.sub.3), 2.60 (s, 3H, CH.sub.3), 2.73 (s, 3H, CH.sub.3), 3.72-4.05 (m, 4H), 6.00 (s, 1), 6.10 (s, 1H), 6.23 (s, 1H), 6.37 (d, J=8.25 Hz, 2H), 6.47 (d, J=8.25 Hz, 2H), 6.64 (d, J=8.25 Hz, 2H), 6.87 (d, J=7.18 Hz, 1H), 6.95 (s, 1H), 7.10 (s, 1H), 7.23 (m, 3H), 7.30 (d, J=7.45 Hz, 1H), 7.38 (m, 4H), 7.47 (m, 1H), 7.64 (d, J=8.52 Hz, 2H), 7.91 (d, J=8.52 Hz, 2H), 8.58 (d, J=7.22 Hz, 1H).

(71) .sup.31P-{.sup.1H} NMR (CD.sub.2Cl.sub.2, 162 MHz, 298K): δ (ppm)=114.2.

Dichloro-{N,N′-bis[2,4,6-(trimethyl)phenyl]imidazolin-2-ylidene}Indenylidene)(p-chlorophenylphosphite) ruthenium (70c)

(72) Using 500 mg of M31 (0.668 mmol), the procedure afforded 496 mg (66%) of the product. .sup.31P-{.sup.1H} NMR (CO.sub.2Cl.sub.2, 162 MHz, 298K): δ (ppm)=115.9.

Dichloro-{N,N′-bis[2,4,6-(trimethyl)phenyl]imidazolin-2-ylidene}Indenylidene)(p-nitrophenylphosphite) ruthenium (70d)

(73) Using 500 mg of M31 (0.668 mmol), the procedure afforded 242 mg (33%) of the product.

(74) .sup.31P-{.sup.1H} NMR (CD.sub.2Cl.sub.2, 162 MHz, 298K): δ (ppm)=115.3.

Dichloro-{N,N′-bis[2,4,6-(trimethyl)phenyl]imidazolin-2-ylidene}Indenylidene)(p-pentafluorosulfurphenylphosphite) ruthenium (70e)

(75) Using 500 mg of M31 (0.668 mmol), the procedure afforded 860 mg (95%) of the product.

(76) .sup.31P-{.sup.1H} NMR (CD.sub.2Cl.sub.2, 162 MHz, 298K): δ (ppm)=114.4.

(77) As an alternative to adjusting the phosphorus containing ligand the NHC ligand may be altered to amend catalyst behaviour. For example providing bulkier ligands on the NHC can promote higher catalytic activity. For example the provision of bulkier alkyl substituents on the aromatic rings of imidazole based NHC ligands can impart improved catalyst behaviour.

(78) The provision of isopropyl groups rather than the methyl groups of complexes such as for example complexes 70 discussed above has been shown to improve catalyst activity, in particular in ROMP polymerisation, using the polymerisation of dicyclopentadiene as an example.

(79) Thus complex 72 prepared as shown below from the known pyridine containing complex 71 performs well in ROMP experiments. Complex 72 is prepared in a trans form as shown below, but it has been shown to behave as a latent catalyst, in particular in ROMP reactions.

(80) ##STR00153##

(81) Inside a glovebox a solution of 71 [RuCl.sub.2(SiPr)Py(Ind)] (500 mg, 0.60 mmol) in toluene (5 mL) was treated with triisopropyl phosphite (163 μL, 0.66 mmol). The reaction mixture was stirred at room temperature (for 6 h) and the solvents removed under vacuum. The resulting solid was washed affording 72 as an orange solid (460 mg, 0.48 mmol, 80%).

(82) .sup.1H NMR (CD.sub.2Cl.sub.2, 400 MHz): □=8.78 (d, J=7.3 Hz, 1H), 7.57 (d, J=7.3 Hz, 2H), 7.46-7.53 (m, 1H), 7.32-7.45 (m, 5H), 7.20-7.28 (m, 1H), 7.10-7.17 (m, 1H), 7.01 (d, J=7.2 Hz, 1H), 6.71-6.77 (m, 1H), 6.58-6.69 (m, 2H), 6.28 (s, 1H), 4.41-4.53 (m, 1H), 4.07-4.21 (m, 1H), 3.90-4.06 (m, 2H), 3.61-3.88 (m, 6H), 3.00 (sept, J=6.7 Hz, 1H), 1.63 (2 d, J=6.7 Hz, 6H), 1.54 (d, J=6.3 Hz, 3H), 1.26 (d, J=6.7 Hz, 3H), 1.22 (t, J=6.3 Hz, 6H), 0.95 (d, J=6.0 Hz, 9H), 0.84-0.84 (m, 1H), 0.86 (d, J=6.8 Hz, 3H), 0.74 (d, J=6.0 Hz, 9H), 0.44 ppm (d, J=6.7 Hz, 3H) .sup.31P NMR (CD.sub.2Cl.sub.2, 121 MHz, CD.sub.2Cl.sub.2) □ 116.65 ppm. .sup.13C NMR (CD.sub.2Cl.sub.2, 101 MHz) □=300.8, 217.3, 150.3, 149.9, 148.3, 147.6, 146.8, 143.5, 143.4, 141.3, 140.8, 137.7, 136.9, 136.8, 136.0, 131.6, 131.5, 130.2, 130.1, 129.5, 129.3, 128.9, 128.2, 127.1, 126.7, 125.6, 125.3, 124.7, 124.0, 117.0, 69.8, 69.2, 69.2, 55.3, 55.2, 55.1, 54.4, 54.3, 54.1, 53.6, 53.3, 30.2, 29.5, 29.3, 28.8, 27.3, 27.2, 27.1, 26.8, 25.6, 24.9, 24.4, 24.3, 24.3, 24.1, 23.8, 23.7, 23.7, 23.6, 28.0, 21.9 ppm Anal. Calcd for C.sub.51H.sub.69Cl.sub.2N.sub.2O.sub.3PRu. (MW 961.05): C, 63.74; H, 5.75; N, 4.61. Found: C, 63.73; H, 7.46; N, 3.02.

(83) ROMP Experiments

(84) Experiments were carried out using complexes of the general form:

(85) ##STR00154##
where the required amount of catalyst was dissolved in dichloromethane (600 microliters) and added to dicyclopentadiene (dcpd −10 mL). The mixture was stirred, poured into the mould and heated to the required temperature to provide polydicyclopentadiene (PDCPD).

(86) Substantial polymerisation did not occur at room temperature, showing the latency of the catalyst. However, the mixtures can form a gel at room temperature indicating some initiation of polymerisation. Heating at temperatures between 40 and 100° C. was required to provide full polymerisation. Thus a smooth controlled polymerisation could be carried out, without e.g. boiling off of the monomer due to an exotherm.

(87) The amount of catalyst used varied between 5 to 60 ppm, based on amount of monomer.

(88) For example, where complex 72 was employed, polymer products having a good aspect (a hard product, conforming to the mould shape) were formed. The polymers also showed good transparency and low odour. These results indicate that high conversion of monomer can be obtained. Additives such as graphite, silica or celite were added in some experiments to make a composite material.

(89) Other complexes, including cis complexes such cis-2 described before also provided polydicyclopentadiene by the procedure described above.

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