Molecular structure of {Cp2Ti(PMe3)}2(.mu.-N2), a titanocene dinitrogen complex

Berry, Donald H.; Procopio, Leo J.; Carroll, Patrick J.

doi:10.1021/om00092a059

Cited by 39 publications

(26 citation statements)

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“…Probably the most striking point is the well‐defined arrangement of the pentafulvene ligands which are located on the same side of the molecule. In general, a selective trans orientation ofthe non‐Cp‐type ligands is found in dinuclear, μ 2 ,η 1 ,η 1 ‐dinitrogen‐bridged titanocene complexes with tetrahedral coor‐dinated titanium centres like [{(η 5 ‐C 5 H 5 ) 2 Ti( p ‐tol)} 2 ‐(μ 2 ,η 1 ,η 1 ‐N 2 )]11 and [{(η 5 ‐C 5 H 5 ) 2 Ti(PMe 3 )} 2 (μ 2 ,η 1 ,η 1 ‐N 2 )] 9. In the case of 6 and 8 , in principle, four different stereoisomers are possible with respect to the position of the exocyclic fulvene carbon atoms (C e ) to each other (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

“…However, this behaviour is different from that of the Ti(II) dinitrogen complexes showing twisted metallocene units [{(η 5 ‐C 5 Me 5 ) 2 Ti} 2 (μ 2 ,η 1 ,η 1 ‐N 2 )] (av. 90°)33 and [{(η 5 ‐C 5 H 5 ) 2 Ti(PMe 3 )} 2 (μ 2 ,η 1 ,η 1 ‐N 2 )] (P–Ti–Ti–P 109°) 9. A nearly perpendicular twist was found also for tantalum–dinitrogen complexes [{(η 5 ‐C 5 Me 5 ) 2 TaCl} 2 (μ 2 ,η 1 ,η 1 ‐N 2 )] (90.8°) 34.…”

Section: Resultsmentioning

confidence: 99%

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Low‐Valent Titanium–Pentafulvene Complexes — Formation of Dinuclear Titanium–Nitrogen Complexes

et al. 2005

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Sodium amalgam reduction of [(η5‐C5Me5)TiCl3] (1) in the presence of the pentafulvenes {C5H4=CR2, R: p‐tol (2), p‐FPh (3), CR2: adamantyl (4)} under nitrogen smoothly produces dark green or dark blue dinuclear low‐valent titanium complexes [{(η5‐C5Me5)Ti(η6‐C5H4=CR2)}2(μ2,η1,η1‐N2)] {R: p‐tol (6), p‐FPh (7), CR2: adamantyl (8)}, characterized by a bridging end‐on coordinated dinitrogen ligand, in high yield. In the same way, the nitrogen‐free, low‐coordinated complex [(η5‐C5Me5)Ti(η6‐C9H6=C(p‐tol)2)] (10) is obtained by using the more sterically demanding benzofulvene C9H6=C(p‐tol)2 (5) instead of 2–4. The solid‐state structures of the dinitrogen compounds reveal weakly activated end‐on bound N2 ligands with identical N–N distances of 1.160(3) Å (6) and 1.160(5) Å (8). The dinitrogen complexes 6, 7 and 8 show diamagnetic behaviour, which allowed a complete NMR spectroscopic characterization. So a correlation between the situation in solution, measured by NMR, and in the solid state (X‐ray diffraction) becomes possible and shows a congruent picture. A broad range of reactions can be imagined concerning the easily replaceable dinitrogen ligand as well as the known reactivity of fulvene ligands in complexes of early transition metals. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Low‐Valent Titanium–Pentafulvene Complexes — Formation of Dinuclear Titanium–Nitrogen Complexes

et al. 2005

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“…First, similar d(N–N) values are observed for the formally Ti II complexes 1-Cp R to the formally Ti III complex 8-Cp, p -tolylide (1.162 Å) and bond lengthening for 8-Cp,PMe 3 (1.191 Å) (Figure ). , Second, the ansa -titanocene in 8- ansa comprises has a slightly contracted bond distance as compared to the 5 - 1 and 5 - 2 as a consequence of the weak π-acidity of the terminal N 2 donors (Figure ). Third, the formally Zr II complex 9-Cp* and the formally Zr III complex 9-Cp,X and the mixed-valent congener Na[9-Cp,X] where X = bis(trimethylsilyl)methyl also have comparable bond lengths (Figure and Figure ) .…”

Section: Dinitrogen Activation By Multimetallic Complexesmentioning

confidence: 99%

Activation of Dinitrogen by Polynuclear Metal Complexes

et al. 2020

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Activation of dinitrogen plays an important role in daily anthropogenic life, and the processes by which this fixation occurs have been a longstanding and significant research focus within the community. One of the major fields of dinitrogen activation research is the use of multimetallic compounds to reduce and/or activate N2 into a more useful nitrogen-atom source, such as ammonia. Here we report a comprehensive review of multimetallic-dinitrogen complexes and their utility toward N2 activation, beginning with the d-block metals from Group 4 to Group 11, then extending to Group 13 (which is exclusively populated by B complexes), and finally the rare-earth and actinide species. The review considers all polynuclear metal aggregates containing two or more metal centers in which dinitrogen is coordinated or activated (i.e., partial or complete cleavage of the N2 triple bond in the observed product). Our survey includes complexes in which mononuclear N2 complexes are used as building blocks to generate homo- or heteromultimetallic dinitrogen species, which allow one to evaluate the potential of heterometallic species for dinitrogen activation. We highlight some of the common trends throughout the periodic table, such as the differences between coordination modes as it relates to N2 activation and potential functionalization and the effect of polarizing the bridging N2 ligand by employing different metal ions of differing Lewis acidities. By providing this comprehensive treatment of polynuclear metal dinitrogen species, this Review aims to outline the past and provide potential future directions for continued research in this area.

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“…At first sight this observation appears to be contradictory. 1.160(3) [7] 2 1.160(5) [7] [{(η 5 -C 5 Me 5 ) 2 Ti} 2 (μ-η 1 :η 1 -N 2 )] 1.165(14) [8] [{(η 5 -C 5 Me 4 H) 2 Ti} 2 (μ-η 1 :η 1 -N 2 )] 1.170(4) [9] [{(η 5 -C 5 H 5 ) 2 Ti(PMe 3 )} 2 (μ-η 1 :η 1 -N 2 )] 1.191(8) [10] [{(η 5 -C 5 H 5 ) 2 Ti(p-tolyl)} 2 (μ-η 1 :η 1 -N 2 )] 1.162(12) [11] [{[η 5 1.289(9) [13] [{(Me 3 Si) 2 NTiCl(py) 2 } 2 (μ-η 1 :η 1 -N 2 )] 1.263(7) [14] [{[(Me 2 N)C(NiPr) 2 ] 2 Ti} 2 (μ-η 1 :η 1 -N 2 )] 1.280(8) [15] In order to address the above statement we investigated compounds 1, 2, and 3 with resonance Raman spec- Scheme 1. troscopy. The vibrational analysis was assisted by DFT calculations performed on structures I and III, which are models of complexes 1/2 and 3, respectively.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Comparison of Dinuclear Ti⁺ and Ti²⁺ μ‐η¹:η¹ Dinitrogen Complexes with Cp*/Pentafulvene and Amine/Amide Ligation: Moderate versus Strong Activation of N₂

et al. 2006

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The two dinuclear, end‐on dinitrogen‐bridged titanium complexes with cp*/pentafulvene ligation, [{(η5‐C5Me5)Ti(η6‐C5H4CR2)}2(μ‐η1:η1‐N2)], R = p‐tolyl (1) and >CR2 = adamantylidene (2), are compared to an analogous titanium dinitrogen complex with a mixed amine/amide/chloride ligand set, [{(Me3Si)2NTiCl(TMEDA)}2(μ‐η1:η1‐N2)] (3; TMEDA = tetramethylethylenediamine). The N–N stretching vibrations of complexes 1 and 2 are observed at 1749 and 1755 cm–1, respectively, indicative of a moderate activation of the dinitrogen ligand. In contrast, the N–N stretch of 3 is located at 1284 cm–1, reflecting a much more highly activated N2 ligand. These findings are in qualitative agreement with N–N bond lengths that have been observed experimentally. DFT calculations reveal that the major difference in the electronic structures of 1, 2, and 3 is the fact that only one of the N2 π* orbitals is (doubly) occupied in the case of 1 and 2, whereas both π* orbitals are (doubly) occupied in the case of 3. The reason for this finding is that in 1 and 2 two of the three electrons of each Ti+ are involved in back‐bonding interactions with the terminal fulvene ligands, whereas no such interactions exist between the Ti2+ centers of 3 and its terminal set of donor ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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Molecular structure of {Cp2Ti(PMe3)}2(.mu.-N2), a titanocene dinitrogen complex

Cited by 39 publications

References 3 publications

Low‐Valent Titanium–Pentafulvene Complexes — Formation of Dinuclear Titanium–Nitrogen Complexes

Low‐Valent Titanium–Pentafulvene Complexes — Formation of Dinuclear Titanium–Nitrogen Complexes

Activation of Dinitrogen by Polynuclear Metal Complexes

Spectroscopic Comparison of Dinuclear Ti⁺ and Ti²⁺ μ‐η¹:η¹ Dinitrogen Complexes with Cp*/Pentafulvene and Amine/Amide Ligation: Moderate versus Strong Activation of N₂

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Molecular structure of {Cp2Ti(PMe3)}2(.mu.-N2), a titanocene dinitrogen complex

Cited by 39 publications

References 3 publications

Low‐Valent Titanium–Pentafulvene Complexes — Formation of Dinuclear Titanium–Nitrogen Complexes

Low‐Valent Titanium–Pentafulvene Complexes — Formation of Dinuclear Titanium–Nitrogen Complexes

Activation of Dinitrogen by Polynuclear Metal Complexes

Spectroscopic Comparison of Dinuclear Ti+ and Ti2+ μ‐η1:η1 Dinitrogen Complexes with Cp*/Pentafulvene and Amine/Amide Ligation: Moderate versus Strong Activation of N2

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Spectroscopic Comparison of Dinuclear Ti⁺ and Ti²⁺ μ‐η¹:η¹ Dinitrogen Complexes with Cp*/Pentafulvene and Amine/Amide Ligation: Moderate versus Strong Activation of N₂