Synthesis of Diindenyldivanadium—a New Variant of the Reductive Degradation of Metallocenes and Related Compounds

Abstract

The complex 4 can be prepared in pure form very much more easily and on a larger scale in a one-pot synthesis starting from vanadocene (Scheme Moreover, when methylcyclohexadiene is used in place of cyclohexadiene, the new vanadium complex cyclopentadienyl(to1uene)vanadium is formed. That 4 reacts with lithium to give 3 is not surprising. Remarkable, however, is the reaction of 4 with magnesium: It leads in tetrahydrofuran to the novel trinuclear complex in which, analogous to the structure of 3b, the benzene ligands probably form bridges between vanadium and magnesium.

Ten‐Electron Donor Indenyl Anion in Binuclear Transition‐Metal Sandwich Complexes: Electronic Structure and Bonding Analysis

“…In the case of V, a singlet ground state is found with the BP86 functional whereas a triplet ground state is found with the B3LYP functional. Experimentally, V 2 (Ind) 2 was reported to be paramagnetic, and to adopt the C 2h configuration with a V−V separation of 2.351 Å . Former ab initio CI calculations by Bénard and coworkers found, similarly as for our BP86 results, the singlet state of V 2 (Ind) 2 to be more stable than the triplet state by 8.3 kcal/mol and suggested that the paramagnetic behavior is due to thermal population of the triplet state …”

“…[4] Whereas the structural chemistry of mononuclear bis-indenyl complexes M(Ind) 2 is fairly documented, [5,6] that of binuclear M 2 (Ind) 2 sandwich complexes is not. To the best of our knowledge, only two X-ray structures of such complexes are known, namely V 2 (Ind) 2 [7] and Co 2 [C 9 H 5 -1,3-(SiMe 3 ) 2 ] 2 . [8] This contrasts with sandwich binuclear complexes of pentalene which have been extensively investigated both on the structural and electronic sides.…”

Indenylvanadium(V)-Verbindungen. Darstellung, Struktur und NMR-spektroskopische Untersuchungen

“…Keywords: Indenylvanadium(V) compounds; Mass spectra; 1 H, 13 C, 51 V NMR; Crystal structure Einleitung Cyclopentadienyl-Komplexe des Vanadiums in allen Oxidationsstufen von +I bis +V sind zahlreich bekannt und untersucht; dagegen sind bisher in der Literatur nur wenige Indenyl-Vanadium-Verbindungen beschrieben: V(g 5 -C 9 H 7 )(CO) 4 [1]; V(g 5 -C 9 H 7 )(CO) 2 (RCºCR) [2]; V(g 5 -C 9 H 7 ) 2 [3]; V 2 (l-g 3:4 -C 9 H 7 ) 2 [3]; V(g 5 -C 9 H 7 )(g 3 -C 9 H 7 )(CO) 2 [4]; V(g 5 -C 9 H 7 ) 2 J [5]; V(g 5 -C 9 H 7 )(g 3 -C 9 H 7 )(C 6 H 5 ) 2 [6]; VO(C 9 H 7 ) 3 [7], Struktur unbekannt. Im Rahmen der Untersuchungen u È ber tert-Butylimidovanadium(V)-Verbindungen haben wir uns mit Cyclopentadienyl-Komplexen bescha È ftigt [8±10].…”

“…2,04 g t C 4 H 9 N = VCl 3 (8,95 mmol) (15) 2,623(6) V(7)±Cl (16) 2,624(5) V (3,7)´´´V (1,2,4,5,6) 3,27±3, 33 V(1,2,4,5,6)´´´V (1,2,4,5,6) 3,52±3,59 N(8)´´´Cl (1) 3,326 N(8)´´´Cl (15) 3,142 N(8)´´´Cl (16) 3,369 N(9)´´´Cl (9) 3,353 N(9)´´´Cl (15) 3,274 N(9)´´´Cl (16) [33] 0,0012(4) Flack-Parameter [34] 0,02 ( …”

Synthesis and properties of bis(indenyl) derivatives of ytterbium and lutetium. Molecular structures of the complexes (C9H7)2Ln(μ-Cl)2Li(Et2O)2 (Ln = Yb, Lu) and [(C9H7)2YbCl2][Li(DME)3]

“…These characteristic features are associated with the coordination nonrigidity of the indenyl ligand, its tendency to undergo haptotropic rearrangements, and the ability to form metal-ligand bonds of different nature depending on the electronic configuration of the central atom. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Recently, we have synthesized the first f transition metal complex with the µ η 5 :η 4 bridging indenyl ligand, whose coordination to two ytterbium atoms gives rise to the dinuclear mixed valence (Yb II /Yb III ) complex. 18 In addition, when investigating the reaction of the ytterbium bis(indenyl) complex (C 9 H 7 ) 2 Yb(THF) 2 with 2 {[(2,6 diisopropylphenyl)imino]methyl}pyridine, we have dis covered 19 the unusual insertion of the N=C double bond at the Yb-C 9 H 7 η 5 bond.…”