Theoretical Insight into the Coordination of Cyclic beta -d-Glucose to [Al(OH)(aq)] super(2+) and [Al(OH) sub(2)(aq)] super(1+) Ions

• Published in: The journal of physical chemistry. B Vol. 118; no. 48; pp. 13890 - 13902
• Main Authors: He, Meng-Fu, Fu, Hong-Quan, Su, Ben-Fang, Yang, Hua-Qing, Tang, Jin-Qiang, Hu, Chang-Wei
• Format: Journal Article
• Language: English
• Published: 04.02.2014
• Subjects: Aluminum; Charge transfer; Ion exchangers; Mathematical models; Molecular dynamics; Orbitals; Oxygen atoms; Polarization
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp5060099

The coordination of cyclic beta -d-glucose (CDG) to both [Al(OH)(aq)] super(2+) and [Al(OH) sub(2)(aq)] super(1+) ions has been theoretically investigated, using quantum chemical calculations at the PBE0/6-311++G(d,p), aug-cc-pvtz level under polarizable continuum model IEF-PCM, and molecular dynamics simulations. [Al(OH)(aq)] super(2+) ion prefers to form both six- and five-coordination complexes, and [Al(OH) sub(2)(aq)] super(+) ion to form four-coordination complex. The two kinds of oxygen atoms (on hydroxyl and ring) of CDG can coordinate to both [Al(OH)(aq)] super(2+) and [Al(OH) sub(2)(aq)] super(+) ions through single-O-ligand and double-O-ligand coordination, wherein there exists some negative charge transfer from the lone pair electron on 2p orbital of the coordinated oxygen atom to the empty 3s orbital of aluminum atom. The charge transfer from both the polarization and H-bond effects stabilizes the coordinated complex. When the CDG coordinates to both [Al(OH)(H sub(2)O) sub(4)] super(2+) and [Al(OH) sub(2)(H sub(2)O) sub(2)] super(1+) ions, the exchange of water with CDG would take place. The six-coordination complex [( eta sub(O4,O6) super(2)-CDG)Al(OH)(H sub(2)O) sub(3)] super(2+) and the five-coordination complex [( eta sub(O4,O6) super(2)-CDG)Al(OH) sub(2)(H sub( 2)O)] super(1+) are predicted to be the thermodynamically most preferable, in which the polarization effect plays a crucial role. The molecular dynamics simulations testify the exchange of water with CDG, and then support a five-coordination complex [( eta sub(O4,O6) super(2)-CDG)Al(OH) sub(2)(H sub( 2)O)] super(1+) as the predominant form of the CDG coordination to [Al(OH) sub(2)(aq)] super(1+) ion.