Synthesis and characterization of titanium tetraisocyanide complexes, [CpTi(CNXyl)4E], E=I, SnPh3, and SnMe3

Allen, Jessica M.; Ellis, John E.

doi:10.1016/j.jorganchem.2007.11.047

Cited by 18 publications

(16 citation statements)

References 33 publications

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“…[34] This value is even larger than those found in [CpTiA C H T U N G T R E N N U N G (CNXyl) 4 ER 3 ] (Xyl = xylene; ER 3 = SnPh 3 : 2.9839(6); E = SnMe 3 : 2.949(1) ), which represent the longest Ti-Sn distances reported to date. [35] Thus, any significant interaction between the metal center and the heteroatom in 3 can be disregarded. As expected, the Ti-E distance increases in the order Scheme 2.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Reactivity of Boron‐, Silicon‐, and Tin‐Bridged ansa‐Cyclopentadienyl–Cycloheptatrienyl Titanium Complexes (Troticenophanes)

Braunschweig

Fuß

Mohapatra

et al. 2010

Chemistry A European J

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A novel one-pot method was developed for the preparation of [Ti(η(5)-C(5)H(5))(η(7)-C(7)H(7))] (troticene, 1) by reaction of sodium cyclopentadienide (NaCp) with [TiCl(4)(thf)(2)], followed by reduction of the intermediate [(η(5)-C(5)H(5))(2)TiCl(2)] with magnesium in the presence of cycloheptatriene (C(7)H(8)). The [n]troticenophanes 3 (n=1), 4, 8, 10 (n=2), and 11 (n=3) were synthesized by salt elimination reactions between dilithiated troticene, [Ti(η(5)-C(5)H(4)Li)(η(7)-C(7)H(6)Li)]⋅pmdta (2) (pmdta = N,N',N',N'',N''-pentamethyldiethylenetriamine), and the appropriate organoelement dichlorides Cl(2)Sn(Mes)(2) (Mes = 2,4,6-trimethylphenyl), Cl(2)Sn(2)(tBu)(4), Cl(2)B(2)(NMe(2))(2), Cl(2)Si(2)Me(4), and (ClSiMe(2))(2)CH(2), respectively. Their structural characterization was carried out by single-crystal X-ray diffraction and multinuclear NMR spectroscopy. The stanna[1]- and stanna[2]troticenophanes 3 and 4 represent the first heteroleptic sandwich complexes bearing Sn atoms in the ansa bridge. The reaction of 3 with [Pt(PEt(3))(3)] resulted in regioselective insertion of the [Pt(PEt(3))(2)] fragment into the Sn-C(ipso) bond between the tin atom and the seven-membered ring, which afforded the platinastanna[2]troticenophane 5. Oxidative addition was also observed upon treatment of 4 with elemental sulfur or selenium, to produce the [3]troticenophanes [Ti(η(5)-C(5)H(4)SntBu(2))(η(7)-C(7)H(6)SntBu(2))E] (6: E=S; 7: E=Se). The B-B bond of the bora[2]troticenophane 8 was readily cleaved by reaction with [Pt(PEt(3))(3)] to form the corresponding oxidative addition product [Ti(η(5)-C(5)H(4)BNMe(2))(η(7)-C(7)H(6)BNMe(2))Pt(PEt(3))(2)] (9). The solid-state structures of compounds 5, 6, and 9 were also determined by single-crystal X-ray diffraction.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Reactivity of Boron‐, Silicon‐, and Tin‐Bridged ansa‐Cyclopentadienyl–Cycloheptatrienyl Titanium Complexes (Troticenophanes)

Braunschweig

Fuß

Mohapatra

et al. 2010

Chemistry A European J

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“…In our exploration of the redox behavior and Ti(II) synthon character of 1 , its reactivity with other π-acids was examined. Isocyanides have been shown capable of stabilizing Ti(II) complexes, − and as CNR is isoelectronic and isolobal to CO, this reagent class seemed an appropriate choice for the attempted isolation of a Ti(II) product. Treatment of a brown, thawing benzene solution of 1 with 2 equiv of CNCy (Cy = cyclohexyl) results in a modest darkening of the solution within a few minutes.…”

Section: Resultsmentioning

confidence: 99%

“…The infrared spectrum of 9 (KBr pellet) (Figure S61) displays a ν CN = 2137 cm –1 that is higher than the range of [NEt 4 ] 3 [Ti(CN) 6 ] (ν CN = 2017 cm –1 ) and K 3 [Ti(CN) 6 ] (ν CN = 2088 cm –1 ) but near that found for [NEt 4 ][Tp*Ti(CN) 3 ] (ν CN = 2116 and 2103 cm –1 ), while the cyano stretching frequency of its coordinated CNCy ligand (ν CN = 2207 cm –1 ) is greater than that reported for the Ti(III) metallocenes Cp* 2 Ti(CNXy)(CCSiMe 3 ) (Xy = xylyl) (ν CN = 2115 cm –1 ) and CpTi(CNXy)I 2 (ν CN = 2156 cm –1 ) . Finally, the EPR spectrum of 9 in toluene and as a solid at 298 K exhibits complicated anisotropic signals in agreement with a Ti(III) center in a low-symmetry ligand environment (Figures S59–S60).…”

Section: Resultsmentioning

confidence: 99%

Redox Character and Small Molecule Reactivity of a Masked Titanium(II) Synthon

et al. 2019

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The two-electron reduction of the Ti(IV) guanidinate (Ketguan)(ImDippN)Ti(OTf)2 (2 OTf ) (Ketguan = [( t Bu2CN)C(NDipp)2]−; ImDippN– = 1,3-bis(Dipp)imidazolin-2-iminato; Dipp = 2,6-diisopropylphenyl) with an excess of KC8 generates the masked complex (Ketguan)(η6-ImDippN)Ti (1). Conversely, reduction of the chloride analogue (Ketguan)(ImDippN)TiCl2 (2 Cl ) with an excess of Na/Hg amalgam produces the Ti(III) compound (Ketguan)(ImDippN)TiCl (3), while treatment of 2 Cl with 3.0 equiv of KC8 affords a complicated mixture from which (ImDippN)(DippN)[η2-( t Bu2C)NC(NDipp)](THF)Ti (4) is isolated as the product of reductive ligand cleavage. These results clearly indicate that the success of early metal reduction chemistry is highly sensitive to the halide coligands and reaction conditions. Complex 1, despite possessing a Ti(IV) canonical form, behaves as a Ti(II) synthon and appreciable reducing agent. For instance, 1 effects the one-electron reduction of benzophenone and pyridine to give the Ti(III) products (Ketguan)(ImDippN)Ti(η1-OC·Ph2) (6) and [(Ketguan)(ImDippN)Ti]2[μ2-(NC5H5–H5C5N)] (7), providing an approximate chemical redox potential range for 1 between ca. −2.3 to −3.1 V (vs [Cp2Fe]0/+). Additionally, treatment of 1 with π-acids such as CNCy (Cy = cyclohexyl) or NC t Bu leads to the formation of the Ti(III) and Ti(IV) products (Ketguan)(ImDippN)Ti(CN)(CNCy) (9) and (ImDippN)[(DippN)(2- i PrC6H3-6-(η1-CH3CHCH2)N)C(NC t Bu2)]Ti[NC(H) t Bu] (10), respectively, via reduction of the π-acid substrate. The two-electron reduction proclivity of 1 is demonstrated by its reactivity with chalcogen sources (e.g., N2O) and organoazides to give the Ti(IV) products (Ketguan)(ImDippN)Ti(E) (E = O (13), S (14), Se (15), S2 (16), NSiMe3 (17), NAd (18)). In addition to illustrating the versatile Ti(II) synthon character of 1, the synthesis of these compounds shows that the 3N-coordinated [(Ketguan)(ImDippN)Ti] n+ manifold can readily accommodate metal–ligand multiple bonds, including relatively rare examples of terminally bound TiS and TiSe bonds. Taken altogether, the redox chemistry of 1, as a Ti(II) synthon, clearly shows the chemical diversity of low-valent early metals (LVEMs) and their ability to reductively activate a wide range of substrates.

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“…It catalyses the dimerisation of neohexene to (E)-2,2,5,6,6-pentamethylhept-3-ene. 68 Organometallics A new type of isocyanide complex, [CpTi(CNXyl) 4 E] (E = I, SnPh 3 , SnMe 3 ), results from reaction of [CpTi(CO) 4 ] À with I 2 , Ph 3 SnCl, and Me 3 SnCl in the presence of CNXyl. 69 [HfCl 4 (PMe 3 ) 2 ] reacts with the 6,6-dimethylcyclohexadienyl anion forming a compound of the stoichiometry [Hf(6,6-dmch) 4 (PMe 3 )].…”

Section: Binary Compoundsmentioning

confidence: 99%

Titanium, zirconium and hafnium

Cotton¹

2009

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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Synthesis and characterization of titanium tetraisocyanide complexes, [CpTi(CNXyl)4E], E=I, SnPh3, and SnMe3

Cited by 18 publications

References 33 publications

Synthesis and Reactivity of Boron‐, Silicon‐, and Tin‐Bridged ansa‐Cyclopentadienyl–Cycloheptatrienyl Titanium Complexes (Troticenophanes)

Synthesis and Reactivity of Boron‐, Silicon‐, and Tin‐Bridged ansa‐Cyclopentadienyl–Cycloheptatrienyl Titanium Complexes (Troticenophanes)

Redox Character and Small Molecule Reactivity of a Masked Titanium(II) Synthon

Titanium, zirconium and hafnium

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