2 Homometallic Alkoxides

336 Alkoxo and Aryloxo Derivatives of Metals
complex [f⊲thf⊳2Lig2f -O⊲SiPh2O⊳2g2SnCl2] the tin is in a distorted trans-octahedral
configuration and the lithium is pseudo-tetrahedral. 469
3.1.2 Sodium
Numerous sodium metal alkoxides have been characterized including the remarkable
complexes [Na8M⊲ 9-Cl⊳⊲ 4-OBu t ⊳⊲ 3-OBu t ⊳8⊲OBu t ⊳](MD Y, Eu) in which a chloride
ion is encapsulated in the cage of a square antiprism of sodium ions capped on
one square face by the six-coordinated yttrium or europium atom (Fig. 4.60). The lone
terminal alkoxo ligand is bonded to the tervalent metal and there are two sets of four
3-bridging alkoxides and one 4-bridging alkoxide on the face opposite the tervalent
metal. 470 In the chloride-free complex [Na3Yf -OCH⊲CF3⊳2g6⊲thf⊳3] theYisina
distorted octahedral coordination and each Na is bonded to two alkoxo ligands and one
terminal THF in a trigonal planar configuration. 471 The yttrium can only accommodate
five of the bulkier ⊲F3C⊳2MeCO ligands and the six-coordination is completed by a
terminal THF in [Na2Yf -OCMe⊲CF3⊳2g4fOCMe⊲CF3⊳2g⊲thf⊳3]. Each Na is bonded
to two alkoxo ligands and a terminal THF. 471 However, there are Na ....F agostic
interactions implying a higher coordination for the Na ion.
In the sodium cerium(IV) tert-butoxide [⊲dme⊳2Na2⊲ 3-OBu t ⊳2⊲ -OBu t ⊳2Ce⊲OBu t ⊳2]
the cerium is in a distorted octahedral configuration with two cis-terminal,
two cis- -bridging and two cis- 3-bridging tert-butoxo groups. Each sodium is
five-coordinated by two 3-bridging and one -bridging Bu t O groups and a
chelating DME ligand. 472 In the Sm(III) compound [Na⊲ , 2 -OR⊳2Ce⊲ 2 -OR 0 ⊳2]
⊲R D C⊲CMe3⊳⊲2-CH2NC5H3Me-6⊳2;R 0 D C⊲CMe3⊳ ž ž2-CHNC5H3Me-6⊳⊳ the Sm is in
distorted octahedral coordination and the Na distorted tetrahedral. 138
A distorted confacial bi-octahedral unit is found in the sodium thorium(IV) complex
[NaTh2⊲ 3-OBu t ⊳2⊲ -OBu t ⊳3⊲OBu t ⊳4] inwhichthetwo 3-ligands cap the NaTh2
triangular unit. 145
In sodium titanium(IV) isopropoxide [Na⊲ -OPr i ⊳4Ti⊲OPr i ⊳]n there is a linear chain
comprising alternating distorted trigonal bipyramidal Ti moieties with very distorted
bridging tetrahedral Na atoms. 473
The anion of the salt ⊲[⊲Ph3P⊳2N] C ⊳3[NafMo3⊲CO⊳6⊲NO⊳3⊲ -OMe⊳3⊲ 3-O⊳g2] 3
has the sodium ion sandwiched in an octahedral coordination by the six bridging
MeO groups of two trinuclear units of octahedrally coordinated triangles of Mo atoms
each capped by a 3-O atom. 474
Figure 4.60 YNa8⊲ 9-Cl⊳⊲ 4-OC⊳⊲ 3-OC⊳8⊲OC⊳
core structure of [YNa8⊲ 9-Cl⊳⊲ 4-OBu t ⊳⊲ 3-
OBu t ⊳8⊲OBu t ⊳](ž D Cl; CH3 groups omitted).