Papers by Andreas Danopoulos
Chemical communications (Cambridge, England), Jan 21, 2015
Unexpected and unprecedented directed remote lateral lithiation at one CH(CH3)2 of the 3-(2,6-di-... more Unexpected and unprecedented directed remote lateral lithiation at one CH(CH3)2 of the 3-(2,6-di-isopropylphenyl) wingtip took place upon the reaction of functionalised N-heterocyclic carbene-type molecules with excess of LiCH2SiMe3, leading to dilithiated dianionic 4-amido-N-heterocyclic carbenes. DFT calculations show that the nature of the isolated species are under thermodynamic control.
Journal of the Chemical Society, Dalton Transactions, 1991
Journal of the Chemical Society, Dalton Transactions, 1991
Journal of the Chemical Society, Chemical Communications, 1990
Journal of the Chemical Society, Dalton Transactions, 1995
ABSTRACT The interaction of Li2W(NBut)4 with PhSCl gave W(NBut)2(η2-PhSNBut)2 the structure of wh... more ABSTRACT The interaction of Li2W(NBut)4 with PhSCl gave W(NBut)2(η2-PhSNBut)2 the structure of which has been determined by X-ray diffraction; reaction of Li(PhSNBut) with transition-metal halides allows the synthesis of range of other compounds with the η2-N,S ligand.
Journal of the Chemical Society Dalton Transactions, 1994
Polyhedron, 1997
The interaction of 2,6-dimethylphenylisocyanide (xylNC) with Cr(Nmes)2(SC6Fs)2 in refluxing tolue... more The interaction of 2,6-dimethylphenylisocyanide (xylNC) with Cr(Nmes)2(SC6Fs)2 in refluxing toluene gives mer-Cr(SC6Fs)3(xylNC)3 1 and minor amounts of trans-Cr(SC6Fs)2(xylNC)4 2. Compound 2 is best made by interaction of either Cr(mes)2(THF)3 or CrCI2 with C6FsSH or C6FsSNa, respectively, in the presence of xylNC. The X-ray crystal structures of 1 and 2 have been determined. The similar imido thiolates of molybdenum(VI) are inert towards xylNC.
Acta Crystallographica Section C Crystal Structure Communications, 2000
Journal of Organometallic Chemistry, 2015
With the aim to favour formation of 'pincer'-type Ir III complexes containing two NHC donor moiet... more With the aim to favour formation of 'pincer'-type Ir III complexes containing two NHC donor moieties, we have used a pro-ligand with a bis-CF 3 -substituted phenylene backbone in order to prevent unwanted backbone cyclometallation. The potential of this new 'pincer' pro-ligand, 1,1 0 -(4,6-bis(trifluoromethyl)-1,3-phenylene)bis(3-butyl-1H-imidazol-3-ium) iodide , is demonstrated by the synthesis and structural characterisation of the 'pincer' Ir III bis carbene benzenide complex (4).
Journal of the Chemical Society, Chemical Communications, 1991
The interaction of NaC5H5 in tetrahydrofuran with a diethyl ether solution of Re(NBut)&I gives ri... more The interaction of NaC5H5 in tetrahydrofuran with a diethyl ether solution of Re(NBut)&I gives rise to a compound [ R e ( N B~f )~( y l -C~H~) l~( p -C~H~) ( p -0 ) that has fluxional y1-C5H5 groups, non-equivalent ButN groups and a unique bridging C5H4 group; the structure has been elucidated by X-ray crystallography.
Coordination Chemistry Reviews, 2007
The coordination and organometallic chemistry of linear, rigid, tridentate ligands, which incorpo... more The coordination and organometallic chemistry of linear, rigid, tridentate ligands, which incorporate at least one N-heterocyclic carbene and other ‘classical’ donors, is reviewed across the periodic table with emphasis on unique features due to the presence of the N-heterocyclic carbene donor.
Chem. Commun., 2016
Studies of ligand dearomatisation in cobalt phosphino-picoline N-heterocyclic carbene (PNC(NHC))-... more Studies of ligand dearomatisation in cobalt phosphino-picoline N-heterocyclic carbene (PNC(NHC))-type pincers have revealed the formation of dinuclear cobalt complexes by either side-arm metalation or C-H activation at the NHC backbone; in the latter case, the product complex, featuring an 'anionic dicarbene', originated from a dearomatised Co(I)-N2 complex.
New Journal of Chemistry, Mar 24, 2003
Introduction of the dianionic 25, 27-O-dimethylated 5, 11, 17, 23-tetra-tert-butylcalix [4] arene... more Introduction of the dianionic 25, 27-O-dimethylated 5, 11, 17, 23-tetra-tert-butylcalix [4] arene spectator, L 2−, to a uranium (IV) centre gave the cyclic trimeric complex 1, which was structurally characterised; complex 1 serves as a useful starting material for further ...
Polyhedron, 1992
Interaction of truns-RuCl,(PMe,), and Li(2,6-Pri2C6H3NH) in THF gives an orange solution which, o... more Interaction of truns-RuCl,(PMe,), and Li(2,6-Pri2C6H3NH) in THF gives an orange solution which, on oxidation by 02, gives blue trans-(2,6-PtzC6H3N),Ru(PMe3), which has been shown to have a planar structure by X-ray diffraction study.
ABSTRACT The interaction of manganese(III) chloride in acetonitrile with NHR(SiMe3)(R = But or CM... more ABSTRACT The interaction of manganese(III) chloride in acetonitrile with NHR(SiMe3)(R = But or CMe2CH2Me) gave the manganese(VII) species Mn(NR)3Cl as thermally and air-stable green crystals. The chlorine atom in Mn(NBut)3Cl 1 has been substituted by Br, OC(O)R (R = Me or CF3). OC6X5(X = F or Cl), OCH(CF3)2′ SC6F5′ C6F5 or NHBut by use of SiMe3Br and the silver, thallium or lithium salts of other reagents. Interaction of compound 1 with Ag(O3SCF3) or AgPF6 and NH2But gave the salts of the cation [Mn(NBut)3(NH2But)]+, with Li(NHBut) under selected conditions gave the paramagnetic manganese(VI) analogues of the manganate(VI) anion, [LiL]2[Mn(NBut)4][L = 1,2-dimethoxyethane (dme) or N,N,N′,N′-tetramethylethylenediamine (tmen)], and with HCl gave Mn(NBut)2(NHBut)Cl2, the reaction being reversed by addition of pyridine. Unstable compounds, e.g Mn(NBut)3(C6F5) and Mn(NBut)3(NHBut), were characterised spectroscopically. The mechanism of the formation of 1 is discussed together with a mechanism accounting for the instability of compounds where the X-group has β-H atoms as in Mn(NBut)3[OCH(CF3)2]. β-Hydrogen transfer to a NBut group to give a manganese(V) dimer [Mn(NBut)2(NHBut)]2 occurs with the formation of ketones from alkoxides; for alkyls decomposition appears to involve homolysis of the Mn–C bond and a radical pathway. The crystal structures of the compounds Mn(NBut)3X, X = OC(O)Me, OC6F5, SC6F5, [Mn(NBut)3(NH2But)]Y, Y = CF3SO3 or PF6 and [Li(dme)]2[Mn(NBut)4] have been determined. In all the compounds the manganese atom has distorted tetrahedral geometry. In the first three the Mn–N(imido) bond lengths are 1.664(3)–1.673(9)Å and the Mn–N–C angles 139.9(2) to 144.6(3)°, indicating partial multiple-bond character. The Mn–X distances, 1.91(3), 1 896(2) and 2.289(1)Å respectively indicate single bonds. In the cationic compounds the Mn–N(imido) distances are 1.531 (8)–1.655(8)Å, with Mn–N–C angles of 1 35.8(6)–170.2(9)°, suggesting more uneven distribution of the Mn–N multiple bonding, although these structures were less precisely determined due to disorder. In the manganate(VI) anion the Mn–N(imido) lengths are longer, 1.746(3)–1.749(3)Å, as expected.
Organometallics, 2004
We 1 and others 2 have recently used 2,6-bis(imidazol-2-ylidene)pyridine and -lutidine ligands fo... more We 1 and others 2 have recently used 2,6-bis(imidazol-2-ylidene)pyridine and -lutidine ligands for the stabilization of catalytically active palladium, rhodium, and ruthenium complexes. The common synthetic routes, i.e., transmetalation from the corresponding silver carbene complexes 1a,b,2c or deprotonation of the bis(imidazolium) salts in the presence of metal precursors, 1d,e,2a,b lead to complexes in which the N-heterocyclic carbene (NHC) ring is metalated via the C-2 atom. Direct metalation of imidazolium salts with basic (acetate or alkoxide) 2a or low-oxidation-state metal complexes 1b,2f leads also to C-2 bonded NHCs. Crabtree was the first to observe "abnormal" C-5 metalation of the NHC ring in bidentate picolyl-and pyridyl-NHC dihydrides of iridium(III), prepared by metalation of imidazolium salts with IrH 5 (PPh 3 ) 2 . 3 Detailed studies of this system by experimental and theoretical methods 3b have shown that the C-5 bound NHC is the kinetic product of direct metalation, assisted by secondary interactions of the C-2 bound hydrogen atom and the imidazolium counteranions.
J Chem Soc Dalton Trans, 1990
Angewandte Chemie (International ed. in English), Jan 14, 2015
The relative lability and transmetallation aptitude of trialkylphosphine and NHC donors, integrat... more The relative lability and transmetallation aptitude of trialkylphosphine and NHC donors, integrated in semi-rigid hybrid ligands attached to [Ag4 Br4 ] pseudo-cubanes, lies in favor of the NHC and is used to selectively access unprecedented NHC complexes with heterobimetallic cores, such as Ag-Cu (4(Cy) ) and Ag-Ir (5(tBu) ). These can be viewed as an arrested state before the full transmetallation of both donors, which gives the homodinuclear Cu (3(Cy) ) and Ir (6(Cy) ) complexes. The observed NHC transmetallation aptitude and reactivity urges caution in the common notion that views the NHC as a universal spectator.
Journal of the Chemical Society, Dalton Transactions, 1994
ABSTRACT The interaction of manganese(III) chloride in acetonitrile with NHR(SiMe3)(R = But or CM... more ABSTRACT The interaction of manganese(III) chloride in acetonitrile with NHR(SiMe3)(R = But or CMe2CH2Me) gave the manganese(VII) species Mn(NR)3Cl as thermally and air-stable green crystals. The chlorine atom in Mn(NBut)3Cl 1 has been substituted by Br, OC(O)R (R = Me or CF3). OC6X5(X = F or Cl), OCH(CF3)2′ SC6F5′ C6F5 or NHBut by use of SiMe3Br and the silver, thallium or lithium salts of other reagents. Interaction of compound 1 with Ag(O3SCF3) or AgPF6 and NH2But gave the salts of the cation [Mn(NBut)3(NH2But)]+, with Li(NHBut) under selected conditions gave the paramagnetic manganese(VI) analogues of the manganate(VI) anion, [LiL]2[Mn(NBut)4][L = 1,2-dimethoxyethane (dme) or N,N,N′,N′-tetramethylethylenediamine (tmen)], and with HCl gave Mn(NBut)2(NHBut)Cl2, the reaction being reversed by addition of pyridine. Unstable compounds, e.g Mn(NBut)3(C6F5) and Mn(NBut)3(NHBut), were characterised spectroscopically. The mechanism of the formation of 1 is discussed together with a mechanism accounting for the instability of compounds where the X-group has β-H atoms as in Mn(NBut)3[OCH(CF3)2]. β-Hydrogen transfer to a NBut group to give a manganese(V) dimer [Mn(NBut)2(NHBut)]2 occurs with the formation of ketones from alkoxides; for alkyls decomposition appears to involve homolysis of the Mn–C bond and a radical pathway. The crystal structures of the compounds Mn(NBut)3X, X = OC(O)Me, OC6F5, SC6F5, [Mn(NBut)3(NH2But)]Y, Y = CF3SO3 or PF6 and [Li(dme)]2[Mn(NBut)4] have been determined. In all the compounds the manganese atom has distorted tetrahedral geometry. In the first three the Mn–N(imido) bond lengths are 1.664(3)–1.673(9)Å and the Mn–N–C angles 139.9(2) to 144.6(3)°, indicating partial multiple-bond character. The Mn–X distances, 1.91(3), 1 896(2) and 2.289(1)Å respectively indicate single bonds. In the cationic compounds the Mn–N(imido) distances are 1.531 (8)–1.655(8)Å, with Mn–N–C angles of 1 35.8(6)–170.2(9)°, suggesting more uneven distribution of the Mn–N multiple bonding, although these structures were less precisely determined due to disorder. In the manganate(VI) anion the Mn–N(imido) lengths are longer, 1.746(3)–1.749(3)Å, as expected.
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Papers by Andreas Danopoulos