Synthese und Struktur von achtgliedrigen Titan- und Zirkon-haltigen Siloxanringen / Synthesis and Structure of Eight-Membered Titanium and Zirconium Containing Siloxane Rings

Trisilane-1,3-diolato Complexes of Ti and Zr: Syntheses and X-ray Crystal Structures

“…As expected, the zirconium and titanium are bonded in a chelate fashion [O1−Zr1−O2 96.18(12)° and O1−Ti1−O2 104.25(3)°] to both siloxide groups of the ligand, giving nearly planar six-membered ring systems. The Zr−O [1.924(3) and 1.917(3) Å] and Ti−O [1.7422(6) and 1.7451(7) Å] distances within the ring are similar to those found in the closely related dinuclear eight-membered ring complexes [(OBu t 2 SiO)MCl 2 ] 2 (M = Ti, Zr), with values being 1.748(2) and 1.746(2) Å for Ti−O as well as 1.930(3) and 1.925(3) Å for the Zr−O bond. Obviously, the ring Zr−O bond lengths are significantly shorter than the Zr−O THF distances [O3−Zr1 2.315(3) Å and O4−Zr1 2.307(3) Å].…”

Syntheses and structure of the first eight‐membered fluoro and chloro hafnium siloxane complexes

“…The compound crystallizes together with two molecules of tetrahydrofuran in the asymmetric unit, one of the THF being disordered among two alternative sites. The structure is very similar to that of the corresponding zirconium compound [2]. (2) 2.4577(13) 2.4636( 13) 1.640 (3) 1.640 (3) 1.906 (4) 1.638 (3) 1.905 (5) 2.294 (3) Cl(l)-Hf(l)-Cl (2) 162.30 (5) The eight-membered Hf2Si,04 ring is planar (deviation 0.035 A) as in the Zr compound (deviation 0,001 A).…”

“…Some of the coordination complexes show special structural and catalytic properties. Regarding group 4, the structures of cyclic titanium and zirconium siloxanes have been investigated [2,3,51. Complexes containing six-membered metallasiloxane systems centered by ionic zirconium and hafnium atoms have been reported [6].…”

(μ-Di-tert-butylsilanediolato)bis[bis(η5-cyclopentadienyl)methylzirconium]

“…In addition, there are 14 structures containing the O 2 Si-t-Bu 2 unit bridging two transition metals that were used for comparison to the O-Si-O angles in 1. These structures include Ti (six structures: Haoudi-Mazzah et al, 1991;Liu et al, 1995), Zr (Haoudi-Mazzah et al, 1991), Hf (Liu et al, 1996), V (Gosink et al, 1993), Nb (Gosink et al, 1994), Mo (Gosink et al, 1993) Packing diagram for one disorder partner of 1, viewed down the c axis.…”

“…HETRED and HETRON (Gosink et al, 1994); JIYBEY ; KIPGUL (Roesky, Mazzah et al, 1991); NADDAX (Liu et al, 1996); PAHZED ; TAJYOS, TAJYUY and TAJZAF (Haoudi-Mazzah et al, 1991); VUMNUM ; WAGVIJ and WAGVOP (Gosink et al, 1993); ZEKKAB and ZEKKEF (Liu et al, 1995).…”