Isolation and Chemistry of Aluminum Compounds Containing (S)-3,3‘-Bis(triphenylsilyl)-1,1‘-bi-2,2‘-naphthoxide Ligands

Abstract

The reaction of the resolved, bulky binol (S)-3,3‘-bis(triphenylsilyl)-2,2‘-dihydroxy-1,1‘-binaphthyl, (S)-H2O2C20H10{SiPh3}2-3,3‘ (1), with a variety of alkyl and amide compounds has been investigated. Reaction of 1 with [Al2Me6] initially proceeds only in a 1:1 ratio to produce dinuclear [Al2(O2C20H10{SiPh3}2-3,3‘)(CH3)4], (S)-2. Compound 2 contains a [Al(μ-C)(μ-O)] core, Al−Al = 2.739(2) Å, with the binaphthoxide ligand oxygen atoms occupying terminal and bridging positions. In the presence of pyridine, 2 reacts further with 1 to produce [Al(O2C20H10{SiPh3}2-3,3‘)(CH3)(py)], (S)-4. The ethyl analogue of 4, [Al(O2C20H10{SiPh3}2-3,3‘)(CH3)(py)], (S)-5, was obtained from [Et2AlCl]. Both 4 and 5 were shown to adopt tetrahedral geometries in the solid state with O−Al−O angles of ∼107°. Reaction of [LiAl(NMe2)4] with 1 produced a dinuclear compound, [LiAl(O2C20H10{SiPh3}2-3,3‘)(NHMe2)(NMe2)2], (S)-6, containing a terminal and bridging amido group. The lithium-bound HNMe2 ligand could be substituted by pyridine to produce [LiAl(O2C20H10{SiPh3}2-3,3‘)(NC6H5)(NMe2)2], (S)-7. In the solid state the formally three-coordinated lithium atoms in 6 and 7 are pyramidalized. The sum of the three angles for the LiN2O core is 305° and 322° for 6 and 7, respectively. This is due to an interaction of the lithium with one arene ring of an SiPh3 group. In 6 the carbon atoms involved are an ipso- and ortho-carbon, while for 7 the ortho- and meta-carbon atoms of a Ph−Si ring are in close contact.

Reactions of Trimethylaluminium: Modelling the Chemical Degradation of Synthetic Lubricants

“…Of these, only five show trapped TMA, demonstrating the highly unusual nature of this phenomenon. The nearest analogues of 6 (TMA) are based on asymmetric bis(oxyphenyl) structures of type I (Figure ) demonstrated by tetraaluminium bis(bis(oxyphenyl)methyl)anthracene and ‐dibenzofuran complexes and the bisaluminium derivative of a 1,1′‐bis‐2,2′‐oxynaphthyl ligand . A type I motif has been recorded once also in heterobimetallic Al–Ti chemistry…”

“…The nearest analogues of 6(TMA) are based on asymmetric bis(oxyphenyl) structures of type I (Figure 5) demonstrated by tetraaluminium bis(bis(oxyphenyl)-methyl)anthracene and -dibenzofuran complexes [38] and the bisaluminiumd erivativeo fa1,1'-bis-2,2'-oxynaphthyl ligand. [39] At ype I motif has been recorded once also in heterobimetallic Al-Tichemistry. [40] The repeated observation that both 2(TMA) and 6(TMA) form alongside Me 2 AlOMe 3 and that crystalline 6(TMA) is isolated contaminated by 3 led to attempts to separate the components.E fforts here took two forms.…”

Structural Effects of Varied Steric Bulk in 2,(4),6‐Substituted Dimethylthallium(III) Phenoxides

“…It should be noted that [Me 2 AlO(2,6-R 2 C 6 H 3 )] 2 [R = iPr, Ph] have C Me -Al-C Me bond angles in the 114.3(6)-116.9(2)°range, whereas [Me 2 -InO(2,6-Me 2 C 6 H 3 )] 2 has a C Me -In-C Me bond angle of 131.0(2)°. [22][23][24] Therefore, the (acute) calculated C Me -Tl-C Me angles are still significantly greater than those observed for structurally characterized aluminum and indium analogues. The difference is even more significant in the monomeric structures, in which the C Me -In-C Me bond angle of [Me 2 InO(2,4,6-tBu 3 C 6 H 2 )] is 109.3(8)°and the C Me -Tl-C Me bond angle of 8 is 170.2(2)°.…”

“…The structure of 7 differs from that of the aluminum analogue [Me 2 AlO(2,6-Ph 2 C 6 H 3 )] 2 , which has a structural arrangement similar to 5 and 6. [24] In contrast to 4-7, the structure of [Me 2 TlO(2,4,6-tBu 3 C 6 H 2 )] (8) (Figure 5) shows the compound to be monomeric in the solid state. The Tl-C Me bond lengths [2.112(5) and 2.123(5) Å] are slightly shorter than those observed for 4-7, while the Tl-O bond length [2.283(3) Å] is significantly shortened.…”

(2,2-Dimethyl-α,α,α′,α′-tetraphenyl-1,3-dioxolane-4,5-dimethanolato-κ2 O 4,O 5)ethyl(tetrahydrofuran-κO)aluminium(III)

“…The molecular structure of (I) has a slightly distorted tetrahedral geometry around the aluminium metal center with short Al-O(TADDOLate) bond lengths of 1.712 (2) and 1.719 (2) Å which are shorter by 0.05 Å than the Al-O(BINOLate) bond distances of 1.762 (1) and 1.754 (1) Å in the tetrahedral Al(BINOLate)py(Et) complex (Son et al, 2003) having a similar seven-membered chelate ring system. The seven-membered chelate TADDOLate O-Al-O angle of 111.19 (10)° is close to the ideal tetrahedral angle comparing to 106.65 (6)° for the Al(BINOLate)py(Et) structure.…”