Synthesis of (.mu.-Bis(aminocarbene))dimetal Complexes of Chromium and Iron by the Reaction of Tertiary Diamides with Cr(CO)52- or Fe(CO)42- in the Presence of Chlorotrimethylsilane

Havránek, M.; Hušák, M.; Dvořák, Dalimil

doi:10.1021/om00011a022

Cited by 19 publications

(12 citation statements)

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“…The coordination of a metal fragment via a carbene carbon to furan has a profound effect on the electronic environment of the ring protons and is clearly reflected in the 1 H and 13 C NMR spectra. The 1 H NMR data for the mono-and biscarbene complexes with furan substituents are given in Table 3.…”

Section: Characterizationmentioning

confidence: 99%

“…In a second approach, the groups of Hegedus and Semmelhack 12 used acyl halides or in situ generated chloroimine intermediates that were treated with nucleophilic transition metal complexes to afford mononuclear aminocarbene complexes. Based on this method, Dvorak and co-workers 13 studied the reaction of tertiary diamides and metal carbonyl dianions in the presence of chlorotrimethylsilane to prepare a series of Cr or Fe homonuclear bimetallic biscarbene complexes as well as one mixed Cr,Fe bis(aminocarbene) complex linked by a benzene moiety in the 1,3-positions.…”

Section: Introductionmentioning

confidence: 99%

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Binuclear biscarbene complexes of furan

2005

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Carbene complexes of chromium and tungsten with a bridging furan substituent were synthesized from lithiated furan precursors and metal hexacarbonyls. The binuclear biscarbene complexes [(CO)5M{C(OEt)-C4H2O-C(OEt)}M'(CO)5](M = M'= Cr (3), W (4)) were obtained as well as the corresponding monocarbene complexes [M{C(OEt)-C(4)H3O}(CO)5](M = Cr (1), W (2)). A method of protecting the carbene moiety during the metal acylate stage was used to increase not only the yields of the binuclear Fischer biscarbene complexes 3 and 4 but to establish a method to synthesize analogous mixed heterobinuclear carbene complexes (M = W, M'= Cr (5)) in high yields. The binuclear biscarbene complexes 3 and 5 were reacted with 3-hexyne and yielded the corresponding benzannulated monocarbene complexes [M{C(OEt)-C14H17O3}(CO)5](M = Cr (6), W(7)). Complex 5 reacted regioselectively with the benzannulation reaction occurring at the chromium-carbene centre. The major products from refluxing 3 in the presence of [Pd(PPh3)4] were a monocarbene-ester complex [Cr{C(OEt)-C4H2O-C(O)OEt}(CO)5](8), the 2,5-diester of furan (9) and a carbene-carbene coupled olefin EtOC(O)-C4H2O-C(OEt)=C(OEt)-C4H2O-C(O)OEt (10). X-Ray structure analysis of 4 and 6 confirmed the molecular structures of the compounds in the solid state and aspects of electron conjugation between the transition metals and the furan substituents in the carbene ligands were investigated.

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Section: Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Binuclear biscarbene complexes of furan

2005

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“…[27] It is worth noting that the orientation of the aromatic ring contrasts with that in the (CrϪFe) complex [(CO) 5 Cr{ϭC(NMe 2 )(m-C 6 H 4 )C(NMe 2 )ϭ}Fe(CO) 4 ] in which the phenyl bridge is perpendicular to the plane of the metalϪcarbene bond. [13] …”

Section: Structure Of Complexes 4a 3a and 4јamentioning

confidence: 99%

“…[10,11] The synthesis of a symmetrical bis(carbene) complex with an ammonium pentadienide bridge has also been described. [12] The formation of bis(aminocarbene)-dichromium complexes [13] has been achieved by reaction of arylbis(amides) with Cr(CO) 5 2Ϫ . Recently, H. Fischer et al reported an efficient synthesis of symmetrically substituted alkynediyl-bridged aminocarbene complexes by Pd coupling of two (CO) 5 MϭC(NR 2 )(CϵC) n units (n ϭ 1,2,3).…”

Section: Introductionmentioning

confidence: 99%

“…A bis(aminocarbene)chromiumϪiron complex has been prepared in two steps by the reaction of a diamide with Cr(CO) 5 2Ϫ and Fe(CO) 4 2Ϫ . [13] An ethyne-bridged (alkoxycarbene)(aminocarbene)ditungsten complex was also recently obtained by the Fischer route starting from an ethynylcarbene complex. [14] We have previously described a convenient route to alkenyl(alkoxy)-and -(amino)carbene complexes of Groups 6 and 8 metals, by activation of propargyl alcohol derivatives.…”

Section: Introductionmentioning

confidence: 99%

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Symmetric and Non-Symmetric Dinuclear Alkenyl-Bridged Carbene Complexes of Chromium and Tungsten

Ulrich

Guerchais

Dötz

et al. 2001

Eur. J. Inorg. Chem.

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Treatment of (CO)5W=C(NMe2)CH=CH−Ar−(OH)(H)C≡CH (1a−b) [a: −Ar− =1,4‐C6H4−; b: −Ar− = 2,5‐C4H2S−] with W(CO)5(THF) in methanol yields the nonsymmetrical bis(alkenylcarbene)‐bridged ditungsten complexes (CO)5W=C(NMe2)CH=CH−Ar−CH=CH(OMe)C=W(CO)5 (3a−b). Similarly, the symmetrical bis(methoxycarbene)ditungsten derivative [(CO)5W=C(OMe)CH=CH−]2(1,4‐C6H4−) (4a) is obtained in a low yield from the precursor (CO)5W=C(OMe)CH=CH−C6H4−(OH)(H)C≡CH (2a). Complexes 3a and 3b undergo aminolysis reactions with diamines such as piperazine and ethylenediamine to produce the corresponding bis[alkenyl(amino)carbene]ditungsten complexes 5a−b and 6a−b. The reaction of 1a with Cr(CO)5(THF) affords the heterobimetallic (W−Cr) bis(carbene) complex (CO)5W=C(NMe2)CH=CH−Ar−CH=CH(OMe)C=Cr(CO)5 (3′a). This complex, as well as the bis(methoxycarbene) derivative 4′a, can also be obtained by treatment of (CO)5W=C(XR)CH=CH−C6H4−CHO [1c: XR = NMe2; 2c: XR = OMe] with (CO)5Cr=C(OMe)CH2−Li+. All the new compounds have been characterized by analytical and spectroscopic methods, and the single‐crystal structures of 3a, 4a−b, and 4′a have been established.

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Polynuclear Complexes with Propynylidene C3-Bridges: General Synthetic Route to Bis-, Tris-, and Tetrakis(ethynylcarbene) Complexes

Hartbaum

Roth

Fischer³

1998

Eur. J. Inorg. Chem.

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The sequential reaction of two equivalents of the dimethylamino(ethynyl)carbene complexes [(CO)5M=C(NMe2)C≡CH] [M = W (1a), Cr (1b)] with two equivalents of nBuLi and one equivalent of a transition metal dichloride, [Cl2M′(Ln)], affords trinuclear biscarbene complexes of the type [(CO)5M=C(NMe2)C≡C−M′(Ln)−C≡CC(NMe)2=M(CO)5] [M′(Ln) = Ni(PEt3)2 (2a, b), Pd(PEt3)2 (3a, b), Pt(PEt3)2 (4a, b), Fe(dmpe)2 (6a), Hg (8a), Ti(η5‐C5H5)2 (9a, b)] [dmpe = 1,2‐bis(dimethylphosphino)ethane]. Treatment of 1a with equimolar amounts of first nBuLi and then [Cl2M′(Ln)] results in the formation of the monosubstitution products [(CO)5W=C(NMe2)C≡CM′(Ln)] [M′(Ln) = trans‐Pd(PEt3)2Cl (5a), trans‐Fe(dmpe)2Cl (7a)]. Additionally, the synthesis of the heterobimetallicethynylcarbene complex [(CO)5W=C(NMe2)C≡CPd(PEt3)2C≡CH] (10a), starting from 1a and [ClPd(PEt3)2C≡CH], is described. When three equivalents of 1a are treated, first with three equivalents of nBuLi and then with one equivalent of the trihalides PCl3 or BBr3, the novel tris(ethynylcarbene) complexes [{(CO)5W=C(NMe2)C≡C}3E] [E = B (11a), P (12a)] are obtained. The reaction of four equivalents of 1a,b with four equivalents of nBuLi, followed by addition of one equivalent of a group 14 tetrachloride [M′Cl4], yields the novel tetrakis(ethynylcarbene) complexes [{(CO)5M=C(NMe2)C≡C}4M′] [M′ = Si (13a, b), Ge (14a), Sn (15a, b)]. The complexes 8a, 9a, 12a, and 15a were characterized by X‐ray structural analyses. All spectroscopic and structural data suggest that the carbene fragments and the central transition metal or heteroatom in these new bis‐, tris‐, and tetrakis(ethynylcarbene) complexes interact only weakly.

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Synthesis of (.mu.-Bis(aminocarbene))dimetal Complexes of Chromium and Iron by the Reaction of Tertiary Diamides with Cr(CO)52- or Fe(CO)42- in the Presence of Chlorotrimethylsilane

Cited by 19 publications

References 0 publications

Binuclear biscarbene complexes of furan

Binuclear biscarbene complexes of furan

Symmetric and Non-Symmetric Dinuclear Alkenyl-Bridged Carbene Complexes of Chromium and Tungsten

Polynuclear Complexes with Propynylidene C3-Bridges: General Synthetic Route to Bis-, Tris-, and Tetrakis(ethynylcarbene) Complexes

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