A new method for the preparation of N-stabilized allenylidene complexes of chromium and tungsten (original) (raw)
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Organometallics, 2002
Reaction of the rhenium(I) allenylidene complex [Re{CdCdCPh 2 }(CO) 2 (triphos)]OTf (1; triphos ) MeC(CH 2 PPh 2 ) 3 , OTf ) -OSO 2 CF 3 ) with thiophenol, 2-thionaphthol, or allyl mercaptan gave selectively the R, -unsaturated thiocarbene complexes [Re{C(SR)CHdCPh 2 }-(CO) 2 (triphos)]OTf (R ) Ph (2), R-naphthyl (3), CH 2 CHdCH 2 (4)). A reversible reaction was observed for PhSH in DMSO at 80°C. Compounds 2 and 3 have been found to react with sodium alkoxides, yielding the kinetic thioallenyl products [Re{C(SR)dCdCPh 2 }(CO) 2 -(triphos)] (R ) Ph (6a), R-naphthyl (7a)). These equilibrated in room-temperature solution with the thermodynamic thioalkynyl products [Re{CtCC(SR)Ph 2 }(CO) 2 (triphos)] (R ) Ph (6b), R-naphthyl (7b)) to give stationary states (6a/6b, 40/60; 7a/7b, 20/80). Deprotonation of the thioallyl complex 4 gave the stable allenyl derivative [Re{C(SCH 2 CHdCH 2 )dCdCPh 2 }-(CO) 2 (triphos)] (8). Ammonia, aniline, and propargylamine each reacted with 1 to give the azoniabutadienyl compounds [Re{C(dNHR)CHdCPh 2 }(CO) 2 (triphos)]OTf (R ) H (9), Ph (10), CH 2 CtCH (11)) via N-H bond addition across the C R dC double bond. NMR spectroscopy showed the γ-alkynylammonium complex [Re{CtCCPh 2 (NH 3 )}(CO) 2 (triphos)]OTf (12) to be a transient intermediate along the reaction of 1 with ammonia. Treatment of 10 or 11 with sodium methoxide resulted in the selective deprotonation of the nitrogen atom to give the azabutadienyl compounds [Re{C(dNR)CHdCPh 2 }(CO) 2 (triphos)] (R ) Ph (13), CH 2 CtCH (14)). The molecular structure of the azoniabutadienyl complex 11 was determined by a single-crystal X-ray analysis. The geometry around the rhenium center conforms to a slightly distorted octahedron, with the polyphosphine sitting on a face of the coordination polyhedron. In keeping with the azoniabutadienyl structure, the Re-C R bond length is 2.151(7) Å, and the C R -N distance is 1.300(9) Å.
Inorganica Chimica Acta, 2009
Bis(ferrocenyl) substituted allenylidene complexes, [(CO) 5 M C C CFc 2 ] (1a c, Fc = (C 5 H 4 )Fe(C 5 H 5 ), M = Cr (a), Mo (b), W (c)) were obtained by sequential reaction of Fc 2 C O with Me 3 Si C CH, KF/MeOH, n BuLi, and [(CO) 5 M(THF)]. For the synthesis of related mono(ferrocenyl)allenylidene chromium complexes, [(CO) 5 Cr C C C(Fc)R] (R = Ph, NMe 2 ), three different routes were developed: (a) reaction of the deprotonated propargylic alcohol HC CC(Fc)(Ph)OH with [(CO) 5 Cr(THF)] followed by desoxygenation with Cl 2 C O, (b) Lewis acid induced alcohol elimination from alkenyl(alkoxy)carbene complexes, [(CO) 5 Cr C(OR)CH C(NMe 2 )Fc], and (c) replacement of OMe in [(CO) 5 Cr C C C(OMe)NMe 2 ] by Fc. Complex 1a was also formed when the mono(ferrocenyl)alleny lidene complex [(CO) 5 Cr C C C(Fc)NMe 2 ] was treated first with Li[Fc] and the resulting adduct then with SiO 2 .
Journal of Organometallic Chemistry, 2004
The allenylidene complex ½Cp à Ru@C@C@CPh 2 ðCOÞðPMe i Pr 2 Þ½BAr 0 4 (1) reacts with benzophenoneimine yielding the azaallenyl derivative ½Cp à RufCðN@CPh 2 ÞCH@CPh 2 gðCOÞðPMe i Pr 2 Þ½BAr 0 4 (2).The addition of primary or secondary amines to 1 yields vinylaminocarbenes, which are better formulated as azoniabutadienyl complexes ½Cp à RufCðNRR 0 ÞCH@CPh 2 gðCOÞ ðPMe i Pr 2 Þ½BAr 0 4 (R = H, R 0 = CH 2 C"CH (3), R = H, R 0 = Me (4), R = R 0 = i Pr ).Tertiary phosphines add to the C a atom of the allenylidene chain furnishing allenylphosphonio species ½Cp à RufCðPR 3 ÞC@CPh 2 gðCOÞðPMe i Pr 2 Þ½BAr 0 4 (PR 3 = PMe 3 (6), PMe i Pr 2 (7)). The reaction of 1 with propanethiol afforded the thiocarbene ½Cp à RufCðS n PrÞCH@CPh 2 gðCOÞðPMe i Pr 2 Þ½BAr 0 4 (8), which can be treated as a g 1 -thiabutadienyl.
Journal of Organometallic Chemistry, 2006
Heterocyclic carbene complexes are accessible from p-donor-substituted allenylidene complexes, [(CO) 5 Cr@C@C@C(NMe 2)Ph] (1) and [(CO) 5 Cr@C@C@C(O-endo-Bornyl)OEt] (4), and various dinucleophiles by 1,2,3-diheterocyclization. The reaction of 1 with 1,2dimethylhydrazine gives the 1,2-dimethylpyrazolylidene complex [(CO) 5 Cr=C-C(H)=C(Ph)-NMe-NMe] (2) in high yield in addition to small amounts of the a,b-unsaturated carbene complex [(CO) 5 Cr@C(NMe 2)-C(H)@C(NMe 2)Ph] (3). The analogous reaction of 4 with 1,2-dimethylhydrazine affords the 1,2-dimethylpyrazolylidene complex [(CO) 5 Cr=C-C(H)=C(O-endo-Bornyl)-NMe-NMe] (5) and, via displacement of the C c-bound ethoxy substituent, the hydrazinoallenylidene complex [(CO) 5 Cr@C@C@C(O-endo-Bornyl){NMe-N(H)Me}] (6). Treatment of 6 with catalytic amounts of acids induces cyclization to 5. On addition of 1,1-dimethylhydrazine to 1 the zwitterionic pyrazolium-5-ylidene complex [(CO) 5 Cr-C=C(H)-C(Ph)=N-NMe 2 ] (7) is formed. The reaction of 1 with 1,2-diaminocyclohexane affords a octahydro-benzo[1,4]diazepinylidene complex (10) and, via intermolecular substitution, a binuclear bisallenylidene complex (11). Thiazepinylidene complexes (12-14), containing 7-membered N/S-heterocyclic carbene ligands, are formed highly selectively in the reaction of 1 with 2-aminoethanethiol or related cysteine derivatives by a substitution/cyclization sequence. The analogous reaction of 1 with homocysteine methylester yields a thiazocanylidene complex (15). All new heterocyclic carbene ligands are strong donors exhibiting r-donor/ p-acceptor ratios similar to those of the known imidazolylidene complexes. On photolysis of 2 and 12 in the presence of triphenylphosphine, the corresponding cis-carbene tetracarbonyl triphenylphosphine complexes (16 and 17) are formed. The solid state structure of complexes 2, 7, 14, 15, and 16 is established by X-ray structural analysis.
Journal of Organometallic Chemistry, 2006
The alkenylaminoallenylidene complex [Ru(g 5-C 9 H 7){@C@C@C(NEt 2)[C(Me)@CPh 2 ]}{j(P)-Ph 2 PCH 2 CH@CH 2 }(PPh 3)][PF 6 ] (2) has been prepared by the reaction of the allenylidene [Ru(g 5-C 9 H 7)(@C@C@CPh 2){j(P)-Ph 2 PCH 2 CH@CH 2 }(PPh 3)][PF 6 ] (1) with the ynamine MeC"CNEt 2. The reaction proceeds regio-and stereoselectively, and the insertion of the ynamine takes place exclusively at the C b @C c bond of the unsaturated chain. The secondary allenylidene [Ru(g 5-C 9 H 7){@C@C@C(H)[C(Me)@CPh 2 ]}{j(P)-Ph 2 PCH 2 CH@CH 2 }(PPh 3)][PF 6 ] (3) is obtained, in a one-pot synthesis, from the reaction of aminoallenylidene 2 with LiBHEt 3 and subsequent treatment with silica. Moreover, the addition of an excess of NaBH 4 to a solution of the complex 2 in THF at room temperature gives exclusively the alkynyl complex [Ru(g 5-C 9 H 7){C"CCH 2 [C(Me)@CPh 2 ]}{j(P)-Ph 2 PCH 2 CH@CH 2 }(PPh 3)] (5). The heating of a solution of allenylidene derivative 3 in THF at reflux gives regio-and diastereoselectively the cyclobutylidene complex [Ru(g 5-C 9 H 7){κ 2 (P,C)-{=CCH(CH 2 PPh 2)CH 2 C=C(H)[C(Me)=CPh 2 ]}}(PPh 3)][PF 6 ] (4) through an intramolecular cycloaddition of the C@C allyl and the C a @C b bonds in the allenylidene complex 3. The structure of complex 4 has been determined by single crystal X-ray diffraction analysis.
Organometallics, 1995
ci~-RuClz(PhzPCHzPPh2)2 (1) reacts with pentadiynes XCWC'CCPhz(OSiMe3) [2 (X = H) and 3 (X = BusSn)], but in the presence of NaPFs, to afford trans-(PhzPCHzPPhZ)z(Cl)-RuCZCCECCPhz(0SiMes) (4). On protonation with HBF4 complex 4 in methanol leads to allenylidene ~~u~~-[(P~zPCHZPP~Z)~(CI)RU=C=C=C(OM~)CH=CP~ZIX (5a) (a: X = BFd and in dichloromethane to ~~~~~-[ (P~~P C H Z P P~Z) Z (C~) R~= C = C = C C H = C~P~~(~-C~H (6a) via electrophilic ortho-substitution within the metallacumulene intermediate LnRu=C=C=C=C= CPhzlX (A). Alternatively, complex 1 and diyne 2 with NaPF6 afford in one step allenylidenes 5b (b: X = PF6) in methanol and 6b in dichloromethane. Bis(diyny1) derivative truns-(Phz-P C H~P P~~) Z R U [ (C = C C~! C (O S~M~~) P~Z ]) Z (7), obtained by reaction of 2 with 1 and HN'PrZ, on protonation with HBF4 in methanol offered a direct route to the first bis(alleny1idene) complex ~~U~~-[(P~ZPCH~PP~Z)ZR~(=C=C=C(OM~)CH=CP~Z)Z~(BF~)Z (8). The X-ray diffraction studies of two allenylidene complexes 6b and 8 are reported. The structure of 6b consists of two different allenylidene cations. That of 8 shows coplanar allenylidene ligands with a strong contribution of a ynyl resonance structure.
Nucleophilic addition reactions to the allenylidene complex [Cp*Ru C C CPh 2(CO)(PMe i Pr 2)] +: X-r
Developments in Petroleum Science, 2004
The allenylidene complex ½Cp à Ru@C@C@CPh 2 ðCOÞðPMe i Pr 2 Þ½BAr 0 4 (1) reacts with benzophenoneimine yielding the azaallenyl derivative ½Cp à RufCðN@CPh 2 ÞCH@CPh 2 gðCOÞðPMe i Pr 2 Þ½BAr 0 4 (2).The addition of primary or secondary amines to 1 yields vinylaminocarbenes, which are better formulated as azoniabutadienyl complexes ½Cp à RufCðNRR 0 ÞCH@CPh 2 gðCOÞ ðPMe i Pr 2 Þ½BAr 0 4 (R = H, R 0 = CH 2 C"CH (3), R = H, R 0 = Me (4), R = R 0 = i Pr (5)).Tertiary phosphines add to the C a atom of the allenylidene chain furnishing allenylphosphonio species ½Cp à RufCðPR 3 ÞC@CPh 2 gðCOÞðPMe i Pr 2 Þ½BAr 0 4 (PR 3 = PMe 3 (6), PMe i Pr 2 (7)). The reaction of 1 with propanethiol afforded the thiocarbene ½Cp à RufCðS n PrÞCH@CPh 2 gðCOÞðPMe i Pr 2 Þ½BAr 0 4 (8), which can be treated as a g 1-thiabutadienyl.
European Journal of Inorganic Chemistry, 1998
The first syntheses of pentacarbonyl[2-(pentamethyl-2,4-case, a dinuclear carbene complex with a P(Cp*)-O-P(Cp*) bridging unit was isolated. Under ordinary reaction cyclopentadien-1-yl)-2H-azaphosphirene]tungsten complexes are reported, using a one-pot reaction of dichloro(pen-conditions 2H-azaphosphirene complexes are slowly transformed into {pentacarbonyl[chloro(pentamethyl-2,4-tamethyl-2,4-cyclopentadien-1-yl)phosphane (Cp*PCl 2) with triethylamine and {[amino(aryl)carbene]pentcarbonyltung-cyclopentadien-1-yl)phosphane]tungsten(0)}. NMR-spectroscopic and single-crystal X-ray structural data of some sten(0)}. [Pentamethyl-2,4-cyclopentadien-1-yl]phosphanediyl-bridged dinuclear carbene complexes are formed as dinuclear carbene complexes and 2-(pentamethyl-2,4cyclopentadien-1-yl)-2H-azaphosphirene complexes are long-lived intermediates, which, by elimination and rearrangement reactions, led to the final products. If traces presented. of water were present, then by-products were formed; in one The chemistry of (2H-azaphosphirene)tungsten com-subsequent transformations (paths a and b) must have occurred very fast, because the mono-condensation products plexes has recently been the subject of increased interest, because of their widespread applicability in the synthesis of 3 could not be detected. Instead, the first products formed in these reactions were the (Cp*-phosphanediyl)-bridged di-three-, [2] four-[3] and five-membered [4] heterocycles. Therefore, our interest in further synthetic investigations was en-nuclear (carbene)metal complexes 4aϪe, aside with small amounts of the 2H-azaphosphirene complexes 6a؊e and hanced, and one of our most important aims was to develop a new access to 2H-azaphosphirene complexes using complex 7. 4aϪe were most probably formed, according to the two pathways a, b depicted in Scheme 1. Path a de-amino(aryl)carbene complexes, a base and dichloro(organo)phosphanes. Compared to [bis(trimethylsilyl)methy-scribes a further condensation, yielding 4aϪe, whereas a base-induced hydrogen chloride elimination, followed by lene]chlorophosphane, which was used in our initial synthetic approach, [5] the advantages should be: the ease of addition of one equivalent of 1 to the short-lived intermediates 5 (cf. ref. [9]), would also explain the generation of the accessibility, the option of introducing P-functional groups into 2H-azaphosphirene complexes and the potential exten-complexes 4aϪe (path b). Interestingly, upon prolonged reaction, complexes 4aϪe eliminated 1 yielding the 2H-aza-sion of this method to condensation reactions of other dichloro(organo)element compounds of group-15 elements. phosphirene complexes 6aϪe, probably by unspecified rearrangements of 5; this elimination reaction has been pro-Furthermore, in order to mimic the bulkyness of the bis(trimethylsilyl)methyl substituent, which is useful for kinetic ven for the case of 4c by treating a pure sample of 4c with triethylamine yielding 6c. We observed that one of the fac-stabilization, we chose pentamethyl-2,4-cyclopentadien-1-yl (denoted hereafter as Cp*) and the corresponding dichloro-tors that limited the yields of 6aϪe was the rate of the reaction of complexes 6aϪe with triethylammonium chloride, phosphane, [6] Cp*PCl 2. Our first attempts to treat amino(aryl)carbene complexes which led to [{Cp*P(H)Cl}W(CO) 5 ] (7) in all cases (Scheme 1). This latter reaction was found to depend strongly on the 1a, b, [7] c, [8] d, e [7] with Cp*Cl 2 (2) at ambient temperature in ether with an excess of triethylamine failed. Therefore, nature of the para-phenyl substituent, the concentration and, most importantly, on the reaction temperature. There-we switched to the more polar solvent dichloromethane for the reactions reported hereafter. According to 31 P-NMR-fore, the temperature had to be kept between 0 and 18°C throughout the reactions and subsequent manipulations. spectroscopic investigations, the first condensation step and Apart from complexes 4aϪe, 6aϪe and 7, two other un-[᭛] Part 12: See ref. [1] .