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Reactions of alkali metal and yttrium alkyls with a sterically demanding bis(aryloxysilyl)methane: Formation of aryloxide complexes by Si-O bond cleavage. CR CHIM 2010. [DOI: 10.1016/j.crci.2010.01.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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52
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Kurzbach D, Yao S, Hinderberger D, Klinkhammer KW. EPR spectroscopic characterization of persistent germyl-substituted Pb(iii)- and Sn(iii)-radicals. Dalton Trans 2010; 39:6449-59. [DOI: 10.1039/c001144d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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53
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Gaderbauer W, Balatoni I, Wagner H, Baumgartner J, Marschner C. Synthesis and structural diversity of oligosilanylzinc compounds. Dalton Trans 2010; 39:1598-603. [DOI: 10.1039/b910463a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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54
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Schrenk C, Schnepf A. Sn[Si(SiMe3)3]3− and Sn3[Si(SiMe3)3]4: first insight into the mechanism of the disproportionation of a tin monohalide gives access to the shortest double bond of tin. Chem Commun (Camb) 2010; 46:6756-8. [DOI: 10.1039/c0cc02367a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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55
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Muñoz-Hernández MÁ, Montiel-Palma V. Polypyrazolates of the heavier group 13 and 14 elements: A review. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2009.06.051] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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56
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Armbruster F, Fernández I, Breher F. Syntheses, structures, and reactivity of poly(pyrazolyl)silanes, -disilanes, and the ambidentate κ1Si/κ3N-coordinating tris(3,5-dimethylpyrazolyl)silanide ligand [Si(3,5-Me2pz)3]− (MeTpsd). Dalton Trans 2009:5612-26. [DOI: 10.1039/b906333a] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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57
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Hauber SO, Niemeyer M. Aryldimethylsilyl Modified Hypersilanes. Z Anorg Allg Chem 2008. [DOI: 10.1002/zaac.200800291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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58
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Becker M, Förster C, Franzen C, Hartrath J, Kirsten E, Knuth J, Klinkhammer KW, Sharma A, Hinderberger D. Persistent radicals of trivalent tin and lead. Inorg Chem 2008; 47:9965-78. [PMID: 18823115 DOI: 10.1021/ic801198p] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this report we present synthetic, crystallographic, and new electron paramagnetic resonance (EPR) spectroscopic work that shows that the synthetic route leading to the recently reported, first persistent plumbyl radical *PbEbt3 (Ebt = ethylbis(trimethylsilyl)silyl), that is, the oxidation of the related PbEbt3-anion, was easily extended to the synthesis of other persistent molecular mononuclear radicals of lead and tin. At first, various novel solvates of homoleptic potassium metallates KSnHyp3 (4a), KPbHyp3 (3a), KSnEbt3 (4b), KPbIbt3 (3c), and KSnIbt3 (4c) (Hyp = tris(trimethylsilyl)silyl, Ibt = isopropylbis(trimethylsilyl)silyl), as well as some heteroleptic metallates, such as [Li(OEt2)2][Sn(n)BuHyp2] (3d), [Li(OEt2)2][Pb(n)BuHyp2] (4d), [Li(thf)4][PbPhHyp2] (3e), and [K(thf)7][PbHyp2{N(SiMe3)2}] (3f), were synthesized and crystallographically characterized. Through oxidation by tin(II) and lead(II) bis(trimethylsilyl)amides or the related 2,6-di-tert-butylphenoxides, they had been oxidized to yield in most cases the corresponding radicals. Five novel persistent homoleptically substituted radicals, that is, *SnHyp3 (2a), *PbHyp3 (1a), *SnEbt3 (2b), *SnIbt3 (2c), and *PbIbt3 (1c), had been characterized by EPR spectroscopy. The stannyl radicals 2a and 2c as well as the plumbyl radical 1c were isolated as intensely colored crystalline compounds and had been characterized by X-ray diffraction. Persistent heteroleptically substituted radicals such as *PbHyp2Ph (1e) or *PbHyp2Et (1g) had also been generated, and some selected EPR data are given for comparison. The plumbyl radicals *PbR3 exhibit a clean monomolecular decay leading to the release of a temperature-dependent stationary concentration of branched silyl radicals. They may thus serve as tunable sources of these reactive species that may be utilized as reagents for mild radical silylations and/or as initiators for radical polymerizations. We present EPR-spectroscopic investigations for the new tin- and lead-containing compounds giving detailed insights into their electronic and geometric structure in solution, as well as structural studies on the crystalline state of the radicals, some of their anionic precursors, and some side-products.
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Affiliation(s)
- Marco Becker
- Institut fur Anorganische and Analytische Chemie, Johannes Gutenberg-Universitat Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
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59
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Inoue S, Ichinohe M, Sekiguchi A. Isolable Alkali-Metal-Substituted Silyl Radicals (tBu2MeSi)2SiM (M = Li, Na, K): Electronically and Sterically Accessible Planar Silyl Radicals. Organometallics 2008. [DOI: 10.1021/om8000185] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shigeyoshi Inoue
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Masaaki Ichinohe
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Akira Sekiguchi
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
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60
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Zirngast M, Baumgartner J, Marschner C. Preparation, Structure and Reactivity of Et2N(Me3Si)2SiK. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200701143] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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61
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Krempner C, Chisholm M, Gallucci J. Der mehrzähnige Ligand (MeOMe2Si)3Si−: ungewöhnliche Koordinationsweisen in Alkalimetallsilaniden. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200703575] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Krempner C, Chisholm M, Gallucci J. The Multidentate Ligand (MeOMe2Si)3Si−: Unusual Coordination Modes in Alkali Metal Silanides. Angew Chem Int Ed Engl 2008; 47:410-3. [DOI: 10.1002/anie.200703575] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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63
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Armstrong DR, Herd E, Graham DV, Hevia E, Kennedy AR, Clegg W, Russo L. Synthesis and structural elucidation of solvent-free and solvated lithium dimethyl (HMDS) zincates. Dalton Trans 2008:1323-30. [DOI: 10.1039/b716494g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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64
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Cortes-Llamas SA, Muñoz-Hernández MÁ. Sodium Polypyrazolylaluminates: Synthesis, Characterization, and Isolation of a Reaction Intermediate of a Trispyrazolylaluminate. Organometallics 2007. [DOI: 10.1021/om700828b] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sara A. Cortes-Llamas
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Colonia Chamilpa, Cuernavaca, Morelos 62209, Mexico
| | - Miguel-Ángel Muñoz-Hernández
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Colonia Chamilpa, Cuernavaca, Morelos 62209, Mexico
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65
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Farwell JD, Hitchcock PB, Lappert MF, Protchenko AV. Synthesis and structures of 3-sila-β-diketiminato complexes of the coinage metals. J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2007.07.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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66
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Beaini S, Deacon GB, Erven AP, Junk PC, Turner DR. Alkali-Metal Pyrazolate Complexes with Unusual Pyrazolate Coordination Modes and Pseudocubane Motifs. Chem Asian J 2007; 2:539-50. [PMID: 17441192 DOI: 10.1002/asia.200700005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The dimeric complex [Li(Ph2pz)(OEt2)]2 (1) and tetrameric cluster [Na(Ph2pz)(thf)]4 (2) were prepared by treatment of alkali-metal reagents (nBuLi and Na{N(SiMe3)2}, respectively) with 3,5-diphenylpyrazole (Ph2pzH) in Et2O (1) or THF (2). The polymer [Na(tBu2pz)]n (3) was obtained from reaction at elevated temperature in a sealed tube between Na metal and 3,5-di-tert-butylpyrazole (tBu2pzH). The complex [Na4(tBu2pz)2(thf)3(obds)]2 (4; obds = (OSiMe2)2O) was obtained as a minor product from prolonged treatment of tBu2pzH with elemental sodium in a silicone-greased flask. All four alkali-metal pyrazolato complexes were characterized by IR and 1H NMR spectroscopy and X-ray crystallography.The Li dimer 1 displays mu-eta(2):eta(1) lithium-pyrazolato binding, in which both lithium atoms are four-coordinate. Room- and variable-temperature NMR studies (1H, 13C, and 7Li) of 1 suggest similar behavior in solution, with peaks coalescing at low temperatures. Complexes 2 and 4 display distorted cubane structures. In 2, all the sodium atoms are five-coordinate, whereas 4 contains two sodium/pyrazolate/thf clusters (4:2:3 ratio) bridged by two obds(2-) units, as well as two four-coordinate and two five-coordinate sodium atoms. Compound 3 is composed of two independent chains with the unusual coordination modes mu3-eta(5):eta(2):eta(2), mu3-eta(5):eta(2):eta(1), and mu3-eta(4):eta(2):eta(1), with five-, six-, and seven-coordinate sodium atoms. Two oxo-centered M8 cage complexes [(tBu2pz)6Li8O] (5) and [(tBu2pz)6Na8O] (6) were obtained as by-products from attempted preparation of [Li(tBu2pz)] and [Na(tBu2pz)], respectively, and their structures were determined.
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Affiliation(s)
- Samar Beaini
- School of Chemistry, Monash University, P.O. Box 23, Clayton, Vic 3800, Australia
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67
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Andrikopoulos PC, Armstrong DR, Kennedy AR, Mulvey RE, O’Hara CT, Rowlings RB, Weatherstone S. Synthesis and structural characterisation of mixed alkali metal–magnesium mixed ligand alkyl-amido ate complexes. Inorganica Chim Acta 2007. [DOI: 10.1016/j.ica.2006.05.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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68
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Liddle ST, Arnold PL. Synthesis and characterisation of yttrium complexes supported by the β-diketiminate ligand {ArNC(CH3)CHC(CH3)NAr}– (Ar = 2,6-Pri2C6H3). Dalton Trans 2007:3305-13. [PMID: 17893777 DOI: 10.1039/b706971e] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of YI(3)(THF)(3.5) with one equivalent of the potassium beta-diketiminate (BDI) complex [HC{C(CH(3))NAr}(2)K] (Ar = 2,6-Pr(i)(2)C(6)H(3)) affords the monomeric, mono-substituted yttrium BDI complex [HC{C(CH(3))NAr}(2)YI(2)(THF)] in good yield. Reaction of with DME affords [HC{C(CH(3))NAr}(2)YI(2)(DME)] in quantitative yield, which is monomeric also. Reaction of the primary terphenyl phosphane Ar*PH(2) (Ar* = 2,6-(2,4,6-Pr(i)(3)C(6)H(2))(2)C(6)H(3)) with potassium hydride, and recrystallisation from hexane, affords the potassium primary terphenyl phosphanide complex [{Ar*P(H)K(THF)}(2)] in high yield. Compound is dimeric in the solid state, constructed around a centrosymmetric K(2)P(2) four-membered ring, the coordination sphere of potassium is supplemented with an eta(6) K[dot dot dot]C(aryl) interaction. The reaction of with one molar equivalent of in THF affords the THF ring-opened compound [HC{C(CH(3))NAr}(2)Y{O(CH(2))(4)P(H)Ar*}(I)(THF)]. Compound is formed as a mixture of endo(OR) and exo(OR) isomers (: = approximately 2 : 1) which may be separated by fractional crystallisation from hexane-toluene to give pure . Attempted alkylation of with two equivalents of KCH(2)Si(CH(3))(3) affords the potassium yttriate complex [Y{micro-eta(5):eta(1)-ArNC(CH(3))[double bond, length as m-dash]CHC([double bond, length as m-dash]CH(2))NAr}(2)K(DME)(2)] in moderate yield; contains two dianionic dianilide ligands, which are derived from C-H activation of a backbone methyl group, each bonded eta(5) to yttrium in the solid state. The reaction of with one equivalent of KC(8) affords [{HC(C[CH(3)]NAr)(2)YI(micro-OCH(3))}(2)], derived from C-O bond activation of DME, as the only isolable product in very low yield. Compounds , , , , , and have been characterised by single crystal X-ray diffraction, NMR spectroscopy and CHN microanalyses.
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Affiliation(s)
- Stephen T Liddle
- School of Chemistry, University Park, University of Nottingham, Nottingham, UK
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69
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70
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Cappello V, Baumgartner J, Dransfeld A, Hassler K. Monophosphanes and Diphosphanes with the Hypersilyl Substituent. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200600444] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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71
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Niemeyer M. Reactions of Hypersilyl Potassium with Rare-Earth Metal Bis(Trimethylsilylamides): Addition versus Peripheral Deprotonation. Inorg Chem 2006; 45:9085-95. [PMID: 17054369 DOI: 10.1021/ic0613659] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The scope of hypersilyl potassium, KHyp [Hyp = Si(SiMe3)3], as a silylation or deprotonation agent for some rare-earth bis(trimethylsilyl)amides has been explored. Thus, the reaction with Yb{N(SiMe3)2}2 affords the addition product [K][YbHyp{N(SiMe3)2}2] (2) in high yield, which contains a three-coordinate ytterbium atom, therefore representing the first example of a lanthanide silyl with a coordination number lower than 6. In contrast, deprotonation on the periphery is observed with the tris(amides) Ln{N(SiMe3)2}3 (Ln = Y, Yb) and compounds of the type [K][CH2Si(Me)2N(SiMe3)Ln{N(SiMe3)2}2] (Ln = Y (3), Yb (4)) are isolated. Crystallization of 3 from a mixture of benzene and heptane afforded the bis(benzene) solvate [(C6H6)2K][CH2Si(Me)2N(SiMe3)Y{N(SiMe3)2}2] (3a). The reaction between the strong bases nBuLi/tetramethylenediamine (TMEDA) or tBuLi with Y{N(SiMe3)2}3 or Yb{N(SiMe3)2}3 yielded the deprotonation product [(tmeda)Li][CH2Si(Me)2N(SiMe3)Y{N(SiMe3)2}2] (6) and the reduction product [LiYb{N(SiMe3)2}3] (7), respectively. Instead of the expected bimetallic product, the reaction between YbI(2) and 2 equiv of 3 gave the neutral complex [Y{CH2Si(Me)2N(SiMe3)}{N(SiMe3)2}(thf)] (8) in good yield. The compounds have been characterized by melting point, elemental analysis, IR spectroscopy, and X-ray crystallography and for selected species by 1H, 13C, 29Si, and 171Yb NMR spectroscopy. For 3a and 4, the nature of the bonding between the carbanionic centers and the lanthanide and potassium cations was studied by density functional theory calculations.
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Affiliation(s)
- Mark Niemeyer
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
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72
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Rofouei MK, Lawless GA, Morsali A, Hitchcock PB. Syntheses and characterization of novel sterically demanding amido ligand derivatives and their alkali metal ion complexes, crystal structures of [SiH2Mes2], [NH(SiHMes2)2] and [Na{N(SiHMes2)2}(OEt2)]. Inorganica Chim Acta 2006. [DOI: 10.1016/j.ica.2006.05.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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73
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Bravo-Zhivotovskii D, Ruderfer I, Melamed S, Botoshansky M, Tumanskii B, Apeloig Y. Nonsolvated, aggregated 1,1-dilithiosilane and the derived silyl radicals. Angew Chem Int Ed Engl 2006; 44:739-43. [PMID: 15612070 DOI: 10.1002/anie.200461765] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Dmitry Bravo-Zhivotovskii
- Department of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel.
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74
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Bravo-Zhivotovskii D, Ruderfer I, Melamed S, Botoshansky M, Schmidt A, Apeloig Y. [{(tBu2Me)2Si}3Li4]2−: An Aggregated Dianion of a 1,1-Dilithiosilane with a Unique Structural Motif. Angew Chem Int Ed Engl 2006; 45:4157-9. [PMID: 16703642 DOI: 10.1002/anie.200600308] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Dmitry Bravo-Zhivotovskii
- Department of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel.
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75
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Bravo-Zhivotovskii D, Ruderfer I, Melamed S, Botoshansky M, Schmidt A, Apeloig Y. [{(tBu2Me)2Si}3Li4]2−: An Aggregated Dianion of a 1,1-Dilithiosilane with a Unique Structural Motif. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600308] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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76
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García F, Hehn JP, Kowenicki RA, McPartlin M, Pask CM, Rothenberger A, Stead ML, Wright DS. Reactions of Sn(NMe2)2 with Alkali-Metal tert-Butylphosphides tBuPHM (M = Li, Na, K): Evidence for Metal-Induced Modification of the Tin(II) Phosphinidene Anions. Organometallics 2006. [DOI: 10.1021/om060167m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Felipe García
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Jörg P. Hehn
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Richard A. Kowenicki
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Mary McPartlin
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Christopher M. Pask
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Alexander Rothenberger
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Matthew L. Stead
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Dominic S. Wright
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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77
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Clegg W, Dale SH, Hevia E, Honeyman GW, Mulvey RE. Pre-Metalation Structural Insights into the Use of Alkali-Metal-Mediated Zincation for Directedortho-Metalation of a Tertiary Aromatic Amide. Angew Chem Int Ed Engl 2006; 45:2370-4. [PMID: 16511891 DOI: 10.1002/anie.200503202] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- William Clegg
- School of Natural Sciences (Chemistry), University of Newcastle, Newcastle upon Tyne NE1 7RU, UK
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78
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Clegg W, Dale SH, Hevia E, Honeyman GW, Mulvey RE. Pre-Metalation Structural Insights into the Use of Alkali-Metal-Mediated Zincation for Directedortho-Metalation of a Tertiary Aromatic Amide. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200503202] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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79
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Wolf R, Hey-Hawkins E. Oligophosphanid-Anionen: Synthesen und Molekülstrukturen von [K2(PMDETA)2(P4Ph4)], [K2(PMDETA)(P4tBu4)]2 und [K(PMDETA)(THF){cyclo-(P5tBu4)}] (PMDETA = NMe(CH2CH2NMe2)2). Z Anorg Allg Chem 2006. [DOI: 10.1002/zaac.200500384] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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80
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Affiliation(s)
- Christoph Marschner
- Institut für Anorganische Chemie, Technische Universität Graz, Stremayrgasse 16, A-8010 Graz, Austria
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81
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Anson CE, Klopper W, Li JS, Ponikiewski L, Rothenberger A. A Close Look at Short CCH3⋅⋅⋅Potassium Contacts: Synthetic and Theoretical Investigations of [M2Co2(μ3-OtBu)2(μ2-OtBu)4(thf)n] (M=Na, K, Rb, thf=tetrahydrofuran). Chemistry 2006; 12:2032-8. [PMID: 16370003 DOI: 10.1002/chem.200500603] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Agostic interactions of the type Si-CH3M+ (M = alkali metal) are frequently mentioned in discussions of solid-state structures of trimethylsilyl compounds and the purpose of this work was to elucidate if they also exist in the related tert-butyl species by using density functional theory. The compounds [M2Co2(mu3-OtBu)2(mu2-OtBu)4(thf)n] (M = Na, n = 2; M = K, n = 0; M = Rb, n = 1) have been synthesised and their crystal structures determined. Close contacts of methyl groups with K atoms are observed in the solid-state structure of [K2Co2(mu3-OtBu)2(mu2-OtBu)4], and calculations of the rotational barrier of a tert-butoxy group about the axis through the C-O bond were performed. It was shown that apparent short C-CH3K distances are in this case a consequence of the packing in the extended solid-state structure.
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Affiliation(s)
- Christopher E Anson
- Institut für Anorganische Chemie, Universität Karlsruhe TH, Engesserstrasse 15, 76131 Karlsruhe (Germany)
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82
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Gehrhus B, Hitchcock PB, Pongtavornpinyo R, Zhang L. Insights into the making of a stable silylene. Dalton Trans 2006:1847-57. [PMID: 16585972 DOI: 10.1039/b514666f] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reduction of Cl2Si[(NR)2C6H4-1,2] (R = CH2Bu(t)) with potassium is known to lead to the stable silylene Si[(NR)2C6H4-1,2] (1). However, silylene is now shown to react further with an alkali metal (Na or K) to yield the (1)(2)2-, c-(1)(3)-*, c-(1)(3)2- or c-(1)(4)2- derivatives. Reduction of Cl2Si[(NR)2C6H4-1,2] (R = CH2CH3 or CH2CHMe2) with potassium does not lead to an isolable silylene, but such a silylene is proposed to be an intermediate and, as for 1, reacts further to afford the potassium salts of c-[Si{(NR)2C6H4-1,2}]4-* and c-[Si{(NR)2C6H4-1,2}](4)2-. The pathways leading to the anionic cyclotri- and cyclotetrasilanes are discussed and supported experimentally; including by X-ray structures of relevant intermediates.
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Affiliation(s)
- Barbara Gehrhus
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton, UKBN1 9QJ
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83
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Strohmann C, Däschlein C, Auer D. Crystal Structures of the Chiral Lithiosilanes [(Lis)-PhMe2SiLi·THF·(−)-Sparteine] and [Ph2(NEt2)SiLi·(−)-Sparteine]. J Am Chem Soc 2005; 128:704-5. [PMID: 16417344 DOI: 10.1021/ja057348k] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The (-)-sparteine-coordinated lithiosilanes (Lis)-4 and 5 crystallize as monomers with coordination numbers of 4 and 3 on lithium and represent the first structurally characterized enantiopure lithiosilanes. Both systems are also monomeric in solution with Si-Li contacts detected by 29Si-7Li couplings in the 29Si NMR spectrum (for 5 even at room temperature).
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Affiliation(s)
- Carsten Strohmann
- Institut für Anorganische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
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84
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Westerhausen M, Sapelza G, Görls H, Mayer P. Synthesis and Characterization of Novel Oxo-Centered Phosphanylzincates of Potassium and Cesium with a Central Zn6O2P4 Double-Heterocubane Cage. Inorg Chem 2005; 45:409-14. [PMID: 16390082 DOI: 10.1021/ic0515195] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The hydrolysis reaction of K(2)(MeZn)(2)(PSitBu(3))(2) in THF/toluene solution yields the [(MeZn)(4)Zn(2)(mu(3)-PSitBu(3))(4)(mu(4)-O)(2)](4-) anions independent of the applied stoichiometry. If the applied molar ratio resembles the composition of the anion, [(thf)K](2)[(eta(6)-toluene)K](2)[(MeZn)(4)Zn(2)(mu(3)-PSitBu(3))(4)(mu(4)-O)(2)] (1) crystallizes from a mixture of THF and toluene. In the case with less water, a phosphanediylzincate moiety is bonded to this anion, and [Zn(PSitBu(3))(2)K(4)(thf)(6)](2)[(MeZn)(4)Zn(2)(mu(3)-PSitBu(3))(4)(mu(4)-O)(2)] (2) crystallizes. However, again the major product is 1. The same anion is also observed with larger and softer cations, and [(thf)(3)Cs(2)](2)[(MeZn)(4)Zn(2)(mu(3)-PSitBu(3))(4)(mu(4)-O)(2)] (3) is obtained if the cesium zincate is used in this reaction. In all of these compounds, the anion is a slightly distorted Zn(6)O(2)P(4) double-heterocubane cage with a central Zn(2)O(2) ring having Zn-O bond lengths of approximately 207 pm.
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Affiliation(s)
- Matthias Westerhausen
- Friedrich-Schiller-Universität Jena, Institute of Inorganic and Analytical Chemistry, Germany.
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85
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Cowley AR, Downs AJ, Marchant S, Macrae VA, Taylor RA, Parsons S. Crystal Structures of Tris(tert-butyl)boron, -aluminum, -gallium, and -indium: Nonplanarity of the AlC3 Skeleton and Evidence of Inter- and Intramolecular “Agostic” or Hyperconjugative Interactions. Organometallics 2005. [DOI: 10.1021/om050572y] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrew R. Cowley
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Anthony J. Downs
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Sarah Marchant
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Victoria A. Macrae
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Russell A. Taylor
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Simon Parsons
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
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86
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87
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Flock M, Marschner C. Silyl Anions or Silylenoids?—A DFT Study of Silyllithium Compounds with π-Donating Substituents. Chemistry 2005; 11:4635-42. [PMID: 15959860 DOI: 10.1002/chem.200401353] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Geometry optimizations at the B3LYP/6-31 + G(d) level for a set of X(SiH3)MeSiLi molecules (X = F, OH, NH2, Cl, SH, and PH2) show that the tetrahedral structure prevails in polar solutions; however, it readily isomerizes into a silylenoid with energy barriers of less than 15 kJ mol(-1). Inverted structures, which predominate in the gas phase, could not be located in solution. Configuration inversion is unfavorable, with energy barriers between 80 and 220 kJ mol(-1). The alpha elimination into a silylene moiety and the corresponding LiX is only likely to occur in solution, particularly for X = Cl and SH.
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Affiliation(s)
- Michaela Flock
- Institute of Inorganic Chemistry, Graz University of Technology, Austria.
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88
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Bravo-Zhivotovskii D, Ruderfer I, Yuzefovich M, Kosa M, Botoshansky M, Tumanskii B, Apeloig Y. Mercury-Substituted Silyl Radical Intermediates in Formation and Fragmentation of Geminal Dimercury Silyl Compounds. Organometallics 2005. [DOI: 10.1021/om050118u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dmitry Bravo-Zhivotovskii
- Department of Chemistry and Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Ilya Ruderfer
- Department of Chemistry and Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Michael Yuzefovich
- Department of Chemistry and Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Monica Kosa
- Department of Chemistry and Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Mark Botoshansky
- Department of Chemistry and Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Boris Tumanskii
- Department of Chemistry and Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Yitzhak Apeloig
- Department of Chemistry and Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion−Israel Institute of Technology, Haifa 32000, Israel
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89
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Teng W, Ruhlandt-Senge K. Syntheses and Structures of the First Heavy-Alkali-Metal Tris(trimethylsilyl)germanides. Chemistry 2005; 11:2462-70. [PMID: 15696585 DOI: 10.1002/chem.200400810] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The first heavy-alkali-metal tris(trimethylsilyl)germanides were obtained in high yield and purity by a simple one-pot reaction involving the treatment of tetrakis(trimethylsilyl)germane, Ge(SiMe3)4, with various alkali metal tert-butoxides. The addition of different sizes of crown ethers or the bidentate TMEDA (TMEDA=N,N,N',N'-tetramethylethylenediamine) provided either contact or separated species in the solid state, whereas in aromatic solvents the germanides dissociate into separated ions, as shown by 29Si NMR spectroscopic studies. Here we report on two series of germanides, one displaying M-Ge bonds in the solid state with the general formula [M(donor)n Ge(SiMe3)3] (M=K, donor=[18]crown-6, n=1, 1; Rb, donor=[18]crown-6, n=1, 4; and M=K, donor=TMEDA, n=2, 6). The silicon analogue of 6, [K(tmeda)2Si(SiMe3)3] (7) is also included to provide a point of reference. The second group of compounds consists of separated ions with the general formula [M(donor)2][Ge(SiMe3)3] (M=K, donor=[15]crown-5, 2; M=K, donor=[12]crown-4, 3; and M=Cs, donor=[18]crown-6, 5). While all target compounds are highly sensitive towards hydrolysis, use of the tridentate nitrogen donor PMDTA (PMDTA=N,N,N',N'',N''-pentamethyldiethylenetriamine) afforded even more reactive species of the composition [K(pmdta)2Ge(SiMe3)3] (8). We also include the silanide analogue [K(pmdta)2Si(SiMe3)3] (9) for sake of comparison. The compounds were typically characterized by X-ray crystallography, and 1H, 13C, and 29Si NMR and IR spectroscopy, unless extremely high reactivity, as observed for the PMDTA adducts 8 and 9, prevented a more detailed characterization.
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Affiliation(s)
- Weijie Teng
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244-4100, USA
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90
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García F, Hopkins AD, Kowenicki RA, McPartlin M, Pask CM, Stead ML, Woods AD, Wright DS. Reactions of Sn(NMe2)2 with Primary Aryl Phosphides, ArPH-: Synthesis and Structures of the Heteroleptic Cages [{(PhP−PPh)Sn(μ-PPh)}2(Na·PMDETA)4 and [{Sn(μ3-Ppy)}3{Sn(μ3,μ1-pyP−Ppy)}3]. Organometallics 2005. [DOI: 10.1021/om049177i] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Felipe García
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., and Department of Health and Biological Sciences, London Metropolitan University, London N7 8DB, U.K
| | - Alexander D. Hopkins
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., and Department of Health and Biological Sciences, London Metropolitan University, London N7 8DB, U.K
| | - Richard A. Kowenicki
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., and Department of Health and Biological Sciences, London Metropolitan University, London N7 8DB, U.K
| | - Mary McPartlin
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., and Department of Health and Biological Sciences, London Metropolitan University, London N7 8DB, U.K
| | - Christopher M. Pask
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., and Department of Health and Biological Sciences, London Metropolitan University, London N7 8DB, U.K
| | - Matthew L. Stead
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., and Department of Health and Biological Sciences, London Metropolitan University, London N7 8DB, U.K
| | - Anthony D. Woods
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., and Department of Health and Biological Sciences, London Metropolitan University, London N7 8DB, U.K
| | - Dominic S. Wright
- Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., and Department of Health and Biological Sciences, London Metropolitan University, London N7 8DB, U.K
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91
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Conway B, Hevia E, Kennedy AR, Mulvey RE, Weatherstone S. Synthesis and characterisation of a series of alkylmagnesium amide and related oxygen-contaminated "alkoxy" compounds. Dalton Trans 2005:1532-44. [PMID: 15824793 DOI: 10.1039/b501502b] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthesised either by an unusual tert-butyl metathesis between tert-butyllithium and a n,s-butylmagnesium amide or by reaction of an alkyl Grignard reagent and a sodium amide, five tert-butylmagnesium amides, Bu(t)MgDBA (5)(DBA=dibenzylamide), Bu(t)MgDA (6)(DA=diisopropylamide), Bu(t)MgHMDS (7)(HMDS=1,1,1,3,3,3-hexamethyldisilazide), Bu(t)MgTMP (8)(TMP=2,2,6,6-tetramethylpiperidide) and Bu(t)MgNCy2 (9)(cy=cyclohexyl) have been isolated as crystalline solids. All five amides have been characterised by X-ray crystallography and solution NMR spectroscopic studies. The former studies reveal a common dimeric molecular structure with amido bridges in a planar (MgN)2 ring and terminal Bu(t) ligands on the Mg atoms. Also described is the dodecameric primary amide [Bu(n)MgN(H)Dipp]12 (10a) and its monomeric solvate Bu(n)MgN(H)Dipp.TMEDA (10b)(Dipp=2,6-diisopropylphenyl; TMEDA=N,N,N',N'-tetramethylethylenediamine). The crystal structures of the oxo-insertion products Bu(t)MgOBu(t).THF (11), Bu(t)Mg(mu-OBu(t))(mu-TMP)MgTMP (12) and Mg(OBu(n))HMDS.solv [solv=THF (13a) or Et2O (13b)], made fortuitously during the course of this work, are also presented.
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Affiliation(s)
- Ben Conway
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK G1 1XL
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92
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93
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Woods JB, Yu X, Chen T, Xue ZL. A Trisilyl Zincate Containing Bidentate [(Me3Si)2Si(CH2)2Si(SiMe3)2]2- Ligands. Organometallics 2004. [DOI: 10.1021/om049277o] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jaime B. Woods
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996
| | - Xianghua Yu
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996
| | - Tianniu Chen
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996
| | - Zi-Ling Xue
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996
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94
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Liddle ST, Izod K. Synthesis and Characterization of 1,3-Diphosphapropene and Alkali-Metal 1,3-Diphosphaallyl Complexes and Unexpected 1,3-Rearrangement of a Cesium 1,3-Diphosphaallyl Complex to a Cesium Secondary Phosphanide. Organometallics 2004. [DOI: 10.1021/om049538u] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stephen T. Liddle
- School of Chemistry, University Park, University of Nottingham, Nottingham NG7 2RD, U.K., and Department of Chemistry, School of Natural Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, U.K
| | - Keith Izod
- School of Chemistry, University Park, University of Nottingham, Nottingham NG7 2RD, U.K., and Department of Chemistry, School of Natural Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, U.K
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95
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Nanjo M, Nanjo E, Mochida K. Tris(trimethylsilyl)‐Substituted Heavy Group 14‐Element‐Centered Anions: Unsolvated Trimeric Germyllithium and Solvated Dimeric Silyl‐ and Stannyllithiums. Eur J Inorg Chem 2004. [DOI: 10.1002/ejic.200300919] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Masato Nanjo
- Department of Chemistry, Faculty of Science, Gakushuin University, Mejiro, Toshima‐ku, Tokyo 171‐8588, Japan, Fax: +81‐3‐5992‐1029
| | - Emi Nanjo
- Department of Chemistry, Faculty of Science, Gakushuin University, Mejiro, Toshima‐ku, Tokyo 171‐8588, Japan, Fax: +81‐3‐5992‐1029
| | - Kunio Mochida
- Department of Chemistry, Faculty of Science, Gakushuin University, Mejiro, Toshima‐ku, Tokyo 171‐8588, Japan, Fax: +81‐3‐5992‐1029
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96
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Teng W, Ruhlandt-Senge K. Syntheses and Structures of the First Heavy Alkaline Earth Metal Bis(tris(trimethylsilyl))silanides. Organometallics 2004. [DOI: 10.1021/om034297w] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Weijie Teng
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244-4100
| | - Karin Ruhlandt-Senge
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244-4100
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97
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Fischer R, Konopa T, Baumgartner J, Marschner C. Small Cyclosilanes: Syntheses and Reactions toward Mono- and Dianions. Organometallics 2004. [DOI: 10.1021/om034396+] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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98
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Stepień M, Latos-Grazyński L, Szterenberg L, Panek J, Latajka Z. Cadmium(II) and Nickel(II) Complexes of Benziporphyrins. A Study of Weak Intramolecular Metal−Arene Interactions. J Am Chem Soc 2004; 126:4566-80. [PMID: 15070375 DOI: 10.1021/ja039384u] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Weak metal-arene interactions have been investigated in Zn, Cd, Hg, and Ni complexes of meso-tetraaryl m- and p-benziporphyrin (1 and 2) and of the new compound, m-benziporphodimethene (3). Compounds 1-3 incorporate the phenylene moiety into a macrocyclic structure so as to facilitate the interaction between the arene and coordinated metal ion. X-ray studies performed on Cd(II) and Ni(II) complexes show that the arene fragment approaches the ion at a distance much shorter than the sum of van der Waals radii. In chloronickel(II) m-benziporphyrin, a weak agostic bond is actually formed. In the NMR spectra of the Cd(II) and Hg(II) species, unusual (1)H-M and (13)C-M scalar couplings have been observed that are transmitted directly between the metal and the arene. DFT calculations performed for two Cd(II) species and subsequent AIM analysis show that the accumulation of electron density between the metal and arene necessary to induce these couplings is fairly small and the interaction is steric in nature. In the paramagnetic Ni(II) complexes of 1 and 3, the agostic proton of the m-phenylene exhibits large downfield (1)H NMR shifts (386 and 208 ppm at 298 K, respectively). An agostic mechanism of spin density transfer is proposed to explain these shifts as resulting from electron donation from the CH bond to the metal. In chloronickel(II) p-benziporphyrin, the inner protons of the p-phenylene have a contrastingly small shift (0.0 ppm at 298 K), indicating that in this case the agostic interaction is inefficient, in agreement with the X-ray data.
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Affiliation(s)
- Marcin Stepień
- Department of Chemistry, University of Wrocław, 14 F. Joliot-Curie St., Wrocław 50 383, Poland
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99
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Teng W, Ruhlandt-Senge K. Syntheses and Structures of the First Heavy Alkaline Earth Metal Germanides M(THF)n(Ge(SiMe3)3)2 (M = Ca, n = 3; M = Sr, n = 3; and M = Ba, n = 4). Organometallics 2004. [DOI: 10.1021/om034157m] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Weijie Teng
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244-4100
| | - Karin Ruhlandt-Senge
- Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse, New York 13244-4100
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100
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