Aluminum-Triggered Condensation of Vicinal Silicate Groups into a Bicyclic Alumosilicate
Por:
Augusto Moreno-Martinez, Victor, Martinez-Otero, Diego, Meza-Gonzalez, Brandon, Cortez-Guzman, Fernando, JANCIK, VOJTECH
Publicada:
18 may 2020
Resumen:
The molecular alumosilicates
AlL{OSi((OBu)-Bu-t)(2)O-[OSi{(mu(3)-O)(MR2)(2)(mu-(OBu)-Bu-t)((O
Bu)-Bu-t)] (L = HC [CMeNAr](2)(-), where M = Al, R = Me (2), Et (3),
and Bu-t (4) and M = Ga, R = Me (5)) were obtained from the reaction of
AIL{OSi-((OBu)-Bu-t)(2)(OH)(2) (1) with 1 or 2 equiv of the
respective organometallic precursor. These compounds have a central
bicyclic inorganic core formed by a six-membered AlSi2O3 alumosilicate
ring with a Si-O-Si unit connected via a Si-O bond to a four-membered
Al2O2 alumoxane ring. These compounds are formed even though 1 is
specifically designed to yield 4R alumosilicate rings that would obey
the Loweinstein's and Dempsey's rules about concatenation between
silicon and aluminum tetrahedra in alumosilicates. We propose a
mechanism for this rearrangement, based on the experimental evidence and
density functional theory calculations, that involves a kappa(3)mu(2)
coordination of a silicate unit to two AlMe2 groups, which weakens one
Si-O bond and explains how aluminum atoms can cleave Si-O bonds.
Furthermore, formation of the products experimentally confirms the
theory that Al-O-Al groups can exist in alumosilicates if the oxygen
atom belongs to an OH moiety.
Filiaciones:
Augusto Moreno-Martinez, Victor:
Univ Nacl Autonoma Mexico, Inst Quim, Ciudad Univ, Ciudad De Mexico 04510, Mexico
Ctr Conjunto Invest Quim Sustentable UAEM UNAM, Toluca 50200, Estado De Mexic, Mexico
Martinez-Otero, Diego:
Univ Nacl Autonoma Mexico, Inst Quim, Ciudad Univ, Ciudad De Mexico 04510, Mexico
Ctr Conjunto Invest Quim Sustentable UAEM UNAM, Toluca 50200, Estado De Mexic, Mexico
Meza-Gonzalez, Brandon:
Univ Nacl Autonoma Mexico, Inst Quim, Ciudad Univ, Ciudad De Mexico 04510, Mexico
Cortez-Guzman, Fernando:
Univ Nacl Autonoma Mexico, Inst Quim, Ciudad Univ, Ciudad De Mexico 04510, Mexico
Ctr Conjunto Invest Quim Sustentable UAEM UNAM, Toluca 50200, Estado De Mexic, Mexico
JANCIK, VOJTECH:
Univ Nacl Autonoma Mexico, Inst Quim, Ciudad Univ, Ciudad De Mexico 04510, Mexico
Ctr Conjunto Invest Quim Sustentable UAEM UNAM, Toluca 50200, Estado De Mexic, Mexico
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