Di(cyclooctatetraene)titanium and Tri(cyclooctatetraene)dititanium

The binuclear cyclooctatetraene sandwich compounds (C8H8)2M2 of the first row transition metals: Analogues of the perpendicular dimetallocenes

“…This gives the nickel atoms in Ni-1S a 16-electron configuration similar to that in the stable bis(allyl)nickel [60,61] Table 3 Bond distances (in Å), total energies (E in Hartree), relative energies (DE in kcal/mol), and spin expectation values hS 2 i for the (C 8 H 8 ) 2 V 2 structures. [19,62] and (g 5 -C 5 H 5 )Co(g 2,2 -C 8 H 8 ) [6,7], which have been structurally characterized by X-ray diffraction. The cluster buildup reaction energies listed in Table 9 leading to the trinuclear clusters (C 8 H 8 ) 3 M 3 are based on the singlet lowest Table 5 Bond distances (in Å), total energies (E in Hartree), relative energies (DE in kcal/mol) and spin expectation values hS 2 i for the (C 8 H 8 ) 2 Mn 2 structures.…”

“…However, analogous bis(octahaptocyclooctatetraene) sandwich compounds with two fully bonded (C 8 H 8 ) 2 M derivatives having one or two partially bonded C 8 H 8 rings. These include (g 8 -C 8 H 8 )M(g 4 -C 8 H 8 ) (M = Ti [19], V [20]) with one octahapto and one tetrahapto C 8 H 8 ring and (g 6 -C 8 H 8 )Fe(g 4 -C 8 H 8 ) [21] with one hexahapto and one tetrahapto C 8 H 8 ring. Neutral (C 8 H 8 ) 2 M derivatives of the first row transition metals Cr, Mn, Co, and Ni do not appear to have been to reported in the literature.…”

“…Related (C 8 H 8 ) 2 M 2 derivatives for the remaining first row transition metals between titanium and nickel remain unknown. In addition, binuclear derivatives (C 8 H 8 ) 3 M 2 (M = Ti [26,27], Cr [19,28], Mo [19], W [19]) containing three cyclooctatetraene rings for two metal atoms have been synthesized and structurally characterized by X-ray crystallography. Such structures have two terminal C 8 H 8 rings and one bridging C 8 H 8 ring.…”

Triple-decker transition metal complexes bridged by a single carbocyclic ring

“…Following the reasoning of Hoffmann et al [30], the complex with an octahapto central COT ring would be characterised by a half-filled degenerate orbital, and therefore does not occur. Although the analogous Cr 2 (COT) 3 , W 2 (COT) 3 and Mo 2 (COT) 3 complexes have also been prepared [116], it has been shown that Cr 2 (COT) 3 takes on a completely different structure from 46, of the cis l-g 5 :g 5 -type [117]. It has been speculated that the structures of W 2 (COT) 3 and Mo 2 (COT) 3 are similar to that of Cr 2 (COT) 3 , since the importance of metal- [117].…”

Low Valent Complexes of Titanium

“…45 [Ti(CgH 8 ) 2 ] (39) was crystallized from hot toluene to afford violet-red crystals in 80% yield. An alternative synthetic path using cyclooctatetraene dianion gave (39) in lower yield (equation 7).…”