Cyclic Carbene Complexes Research Articles

Übergangsmetall-Carben-Komplexe, CXXXI. Umsetzung von [(CO)5WCNEt2]BF4 mit anionischen Organylverbindungen von Elementen der V. Hauptgruppe/ Transition Metal Carbene Complexes, CXXXI. Reaction of [(CO)sWCNEt2]BF4 with Anionic Organyl Compounds of Group V Elements

Abstract The cationic carbyne complex [(CO)5WCNEt2]BF4 (1) reacts with potassiumdiphenylamide, KNPh2, with nucleophilic addition of the amide anion to give (CO)5W[C(NEt2)NPh2] (2). The corresponding reactions with KPPh2, KPEt2, KPMePh, NaSbPh2 and NaBiPh2 yield the complex [(CO)5W(CNEt2)]2 (3), which is formed by reductive dimerization of two carbyne fragments. In case of KPMePh the carbene complexes (CO)5W[C(NEt2)PMePh (4) and trans-(MePhPH)(CO)4W[C(NEt2)PMePh] (5) are also obtained. On warming in solution 5 spontaneously rearranges to the novel cyclic carbene complex (6). Reaction conditions, properties and spectroscopic data of the new compounds are reported.

Cyclic carbene complexes of molybdenum and tungsten. Crystal and molecular structure of [Mol(CO)2{CO(CH2)2CH2}(η-C5H5)

The cyclic carbene complex [Mol(CO)2{[graphic omitted]H2}(η-C5H5)] is formed during reaction of [Mo(CO)3(η-C5H5)]– with I[CH2]3l or of [Mo{(CH2)3Br}(CO)3(η-C5H5)] with Lil. Crystals of this complex are Monoclinic, space group P21/c, with a= 6.372(2), b= 14.168(5), c= 14.390(3)A, β= 98.12(2)°, and Z= 4. The molecule contains mutually trans carbonyl ligands and a cyclic carbene ligand in which all but one of the ring carbon atoms are coplanar with the metal. Similarly, reactions of [Mo{(CH2)3Br}(CO)3(η-C5H5)] with SPh– or CN– provide [MoX(CO)2{[graphic omitted]H2}(η-C5H5)](X = SPh or CN). The cyclisation is tolerant to functionality on the cyclopentadienyl ring, thus reaction of [Mo(CO)3(η-C5H4R)]– with I[CH2]3l produces [Mol(CO)2{[graphic omitted]H2}(η-C5H4R)][R = Me, C(O)Me, or SiMe3]. The tungsten analogue [W{(CH2)3Br}(CO)3(η-C5H5)] undergoes carbene formations with l– and CN– to form [WX(CO)2{[graphic omitted]H2}(η-C5H5)](X = l or CN). Formation of the carbene complexes is likely to proceed by migration of the (CH2)3Br alkyl group to an adjacent CO group together with co-ordination of the incoming anion. This is followed by a ring closure reaction eliminating Br– and isomerisation so that in all cases the two CO groups are mutually trans in the isolated products. While [Mol(CO)2{[graphic omitted]H2}(η-C5H5)] does not react with transition-metal anions to form dinuclear carbene complexes by elimination of l–, the salt [Mo(CO)2(PPh3){[graphic omitted]H2}(η-C5H5)]Br reacts with [W(CO)3(η-C5H5)]– to give the unusual acyl complex [(η-C5H5)(Ph3P)(OC)2MoC(O)(CH2)3W(CO)3(η-C5H5)].

Reactions of a dichlorocarbene-ruthenium complex, RuCl 2(CCl 2)(CO)(PPh 3) 2

The dichlorocarbene ligand, in the new complex ab]RuCl 2(CCl 2)(CO)(PPh 3) 2, readily undergoes substitution reactions in which the integrity of the metal-carbon bond is maintained. Reactions with species H 2X (X = O, S, Se) give chalcocarbonyl complexes RuCl 2(CX)(CO)(PPh 3) 2 while RXH (X = O, S) give new carbene complexes RuCl 2[C(XR) 2](CO)(PPh 3) 2. Ammonia reacts to give a cyanide-containing complex, RuCl(CN)(CO)(NH 3)(PPh 3) 2, andprimary amines, an isocyanide complex, or in the case of certain primary diamines cyclic carbene complexes. RuCl 2(CNNMe 2)(CO)(PPh 3) 2 is formed in the reaction with N,N-dimethylhydrazine. Secondary amines, R 2NH, react to give chloroaminocarbene complexes, RuCl 2[C(Cl)NR 2](CO)(PPh 3) 2.

Metal cyclic carbene complexes. A molybdenum complex of 2-oxacyclopentylidence: synthesis and X-ray structure of [MoI(CO)2(C4H6O)(η-C5H5)

Reaction of [Mo(CO)3(η-C5H6)]– with I[CH2]3I in tetrahydrofuran (THF) or of [Mo{[CH2]3Br}(CO)3(η-C5H5)] with LiI in THF affords the carbene complex [MoI(CO)2{[graphic omitted]H2}(η-C5H5)], which has been characterised by X-ray diffraction, while treatment of [Mo(CO)3(η-C5H5)]– with I[CH2]4I leads to [(η-C5H5)(OC)3Mo[CH2]4Mo(CO)3(η-C5H5)].

Mesityl- and pentachlorophenyl-nickel(II) complexes with the cyclic alkoxyvinyl group or alkyl(alkoxy)carbene ligand: the relative Bronsted acidity and the rotational barrier about the nickel–carbon bønd

Cyclic α-alkoxyvinylnickel(II) complexes of the types trans-[NiRL2([graphic omitted])] and trans-[NiRL2-([graphic omitted])](R = C6H2Me3-2,4,6 or C6Cl5 and L = PMe3 or PMe2Ph) have been prepared from trans-[NiRL2X](X = Cl or Br) and 2,3-dihydro-5-lithiofuran or 2,3-dihydro-6-lithiopyran. Treatment of these complexes with aqueous perchloric acid gives the corresponding cationic cyclic carbene complexes, trans-[NiRL2([graphic omitted])][ClO4] and trans-[NiRL2([graphic omitted])][ClO4]. The carbene complexes of trans-Ni(C6H2Me3-2,4,6)L2 have a lower Bronsted acidity than those of trans-Ni(C6Cl5)L2 and the barriers to rotation of the cyclic alkoxyvinyl groups and the cyclic alkyl(alkoxy)carbene ligands about the Ni–C bond are lower for the former complexes than for the latter. These results are intepreted in terms of the stronger trans influence of the C6H2Me3-2,4,6 group.

Reaktionen von chrom- und wolframhexacarbonyl mit dilithio-2-methly-3-butinyl-2-olat (LiCCC(CH 3) 2OLi). synthese von carben- und cumulenylidencarben-komplexen

The reactions of M(CO) 6 (M = Cr, W) with LiCCC(CH 3) 2OLi leading to the corresponding acylate complexes are reported. Treatment of these complexes with CH 3COCl or HCl leads to the novel cyclic carbene complexes [2,2,6,6-tetramethyl-4 H, 6 H-2,3-dihydrofuro[3.4- b]furan-di-3,4-ylidene]-3-[2-ethylidenepentacarbonylchromium(0)]-4-pentacarbonylchromium(0) (2) and [2,2-dimethyl-3-chlorofuro-3-en-5-ylidene]-5-pentacarbonyltungsten(0) (3). The photolysis of the initially formed (CO) 5CrC(O)CCC(CH 3) 2OLi 2 and the subsequent reaction with CH 3COCl yields the vinylidene complex (CO) 5CrCC(COCH 3)C(CH 3) 2OCOCH 3 (4). The X-ray structure of compound 2 is reported.

Novel cyclic carbene complexes of iron

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNovel cyclic carbene complexes of ironYasuhiro Yamamoto, Katsuyuki Aoki, and Hiroshi YamazakiCite this: J. Am. Chem. Soc. 1974, 96, 8, 2647–2648Publication Date (Print):April 1, 1974Publication History Published online1 May 2002Published inissue 1 April 1974https://doi.org/10.1021/ja00815a073RIGHTS & PERMISSIONSArticle Views81Altmetric-Citations31LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (240 KB) Get e-Alerts Get e-Alerts

Cationic cyclic carbene complexes of iridium(III), nickel(II), palladium(II), and platinum(II)

Reaction of the 2-chloro-derivatives of 5-methyl-1,3-thiazole, benzthiazole, and benzoxazole with IrCl(CO)(PMe2Ph)2 affords IrIII complexes which on protonation yield cationic carbene complexes [IrCl2(CO)(PMe2Ph)2(L)]+(L = [graphic omitted], [graphic omitted], [graphic omitted]). Treatment of IrCl(CO)(PMe2Ph)2 with the N-methyl salt of 2-chloro-5-methyl-1,3-thiazole, [Cl[graphic omitted]][BF4], affords the carbene complex [IrCl2(CO)(PMe2Ph)2{[graphic omitted]}][BF4]. Similar oxidative-addition of [Cl[graphic omitted]][BF4] to Pt(PEt3)2(stilbene), Pt(PMePh2)4, PdL4(L = PPh3, PMePh2) or Ni(PPh3)4 gives cationic carbene complexes of PtII, PdII, and NiII. The complex [PtCl{[graphic omitted]}(PEt3)2][BF4] was obtained by treating PtCl([graphic omitted])(PEt3)2 with fluoroboric acid. Some chemical and spectroscopic properties of the new complexes are discussed.

Cationic cyclic carbene or carbon-bonded ylide complexes of iridium(III) and platinum(II)

2-Chloro-4-methylthiazole, 2-chlorobenzoxazole and 2-chlorobenzthiazole oxidatively add to both [IrCl(CO)(PMe 2Ph) 2] and [Pt(PhCHCHPh)(PEt 3) 2]; protonation of the products at nitrogen produces cationic carbene complexes.

The structure of King's Mn2(CO)10(CH2)3: a cyclic metal–carbene complex

The structure of King's Mn2(CO)10(CH2)3 is shown to be the cyclic carbene complex (2) and not (1) as originally suggested by King.