Tetralithium Bis(ethylaluminum) Tetrakis(catecholate) Pentakis(dimethoxyethane): An Oxygen-Rich Cluster [(Al++2(Li+)4(O18)−8] in a C36H44 Hydrocarbon Shell

Abstract

The structure determination of the lipophilically wrapped cluster {[Al2Li4O18](C36H44)}∞, a novel material crystallized from a mixture of [(C2H5)3Al]2, nBuLi, and catechol in DME solution, reveals five‐coordinate Al++ and Li+ centers. According to density functional theory calculations, the eight negative charges are well‐delocalized over the oxygen‐rich framework.

Preparation, Structure, and Density Functional Calculation of the Solvent-Separated Ion Pair [(H5C2)Al(OC6H5)3-···Li+···-(H5C6O)3Al(C4H9)]-[Li+(DME)3]

“…The structure determination shows polymeric strands of dimethoxyethane-bridged and subunits connected via four-membered (Li 2 O 2 ) rings, {(DME 1.5 Li + )(H 5 C 2 Al 2+ ( 2- O 2 C 6 H 4 ) 2 (Li + DME)}. The formally 2-fold positive (H 5 C 2 )Al 2+ fragments are 4-fold coordinated to four oxygen anion centers of two catecholate ligands . The space-filling representation of the structure (Scheme ) convincingly demonstrates the complete lipophilic wrapping of the oxygen-rich polyion aggregate [(Al 2+ ) 2 (Li + ) 4 (O 18 ) 8-11 ] by its hydrocarbon skin (C 38 H 46 ) …”

“…The formally 2-fold positive (H 5 C 2 )Al 2+ fragments are 4-fold coordinated to four oxygen anion centers of two catecholate ligands . The space-filling representation of the structure (Scheme ) convincingly demonstrates the complete lipophilic wrapping of the oxygen-rich polyion aggregate [(Al 2+ ) 2 (Li + ) 4 (O 18 ) 8-11 ] by its hydrocarbon skin (C 38 H 46 ) 1 …”

“…Lipophilically wrapped polyion aggregates contain a metal salt cluster nucleus [(Me n + X n - ], which guarantees thermodynamic stabilization, and are surrounded by a hydrocarbon skin from the ligands X - (C n H m ), which provides both kinetic shielding and solubility in nonpolar solvents. Within the last year, these aggregates proved to be an advantageous self-organization principle also for main group element compounds. , On the basis of the structural information collected, the density functional as well as semiempirical calculations that were performed, 2a,b and the experience gathered in crystallization with small temperature or concentration gradients,2d the so far serendipitous self-assembly of suitable compounds to lipophilically wrapped polyion aggregates can now be planned to some extent. For instance, starting from the considerable enthalpy difference between (Al−C) vs (Al−O) bonds, dimeric aluminum triethyl has been reacted under argon in dimethoxyethane solution with stoichiometric amounts of catechol and n -butyllithium …”

Use of group 13 aryloxides for the synthesis of green chemicals and oxide materials

“…, [Me 2 AlLi(OAr) 2 ], 87 and [MeAlLi(OAr)(OCMePhPh)(Et 2 O)] 88 where OAr = 2,6-di- t -butyl-4-methylphenoxide; [AlLi(EDBP) 2 (THF) 2 ] where EDBP = 2,2′-ethylidenebis(4,6-di- tert -butylphenolato); 89 [AlLi(binol)(THF) 2 ((CH 2 ) 5 CO)]; 39 [AlLi(binol)(O t Bu) 2 (PMDTA)] where PMDTA = N , N , N ′, N ′′, N ′′-pentamethyldiethylenetriamine, [AlLi(binol)(O t Bu) 2 (THF) 2 ], [Al 2 Li 2 (binol) 4 (THF) 4 ]; 90 [Me 2 AlLi(OAr) 2 ] 2 where OAr = 2,6-dimethoxyphenoxide, 91 [Et 2 Al 2 Li 2 (OAr) 4 (DME) 3 ] n where OAr = catecholato. 92 For the Al : Li ratio of 2 : 1 or 1 : 3, only the structures of [R 2 Al 2 Li(OPh) 6 (THF) 6 ] (for R = Et, n Bu), 93 or [AlLi 3 (binol) 3 (THF) 6 ] 90 have been reported. For heterometallic aluminum–lithium compounds, the double open dicubane unit was observed only in the structure of [Al 2 Li 2 (OR) 8 ] for RO = hexafluoropropoxide.…”

Wechselwirkungen in Molekülkristallen, 157 [1, 2]. Mischkristallzüchtung und Strukturbestimmungen von Tetra(3,4-dimethylphenyl)-imidodiphosphat-Salzen mit Alkalikation- Verhältnissen K⊕/Rb⊕(1:5) und Rb⊕/Cs⊕(1:1) / Interaction in Molecular Crystals, 157 [1, 2]. Mixed Crystal Growth and Structure Determinations of Tetrakis(3,4-dimethylphenyl)-imidodiphosphate Salts with Alkali Cation Ratios K⊕/Rb⊕ (1:5) and Rb⊕/Cs⊕ (1:1)

“…Solvatationseffekte [3] und die hierdurch beein flußten Aggregationen zu lipophil umhüllten Clu stern [4,5] lassen sich vorteilhaft mit kugelförmi gen Alkalimetall-Monokationen untersuchen. Die ersten vertikalen Ionisationsenergien IE jv der Alkalimetallatome entsprechen effektiven Kernladungen nach Slater [6] und korrelieren mit den unterschied lich großen Radien der verschiedenartig geladenen Teilchen Me0, Me6® und Me® [7] (1).…”