File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: Mechanismic Investigation on the Cleavage of Phosphate Monoester Catalyzed by Unsymmetrical Macrocyclic Dinuclear Complexes: The Selection of Metal Centers and the Intrinsic Flexibility of the Ligand

TitleMechanismic Investigation on the Cleavage of Phosphate Monoester Catalyzed by Unsymmetrical Macrocyclic Dinuclear Complexes: The Selection of Metal Centers and the Intrinsic Flexibility of the Ligand
Authors
Issue Date2014
Citation
Inorganic Chemistry, 2014, v. 53, p. 3354-3361 How to Cite?
AbstractThe hydrolysis mechanisms of phosphor-monoester monoanions NPP(-) (p-nitrophenyl phosphate) catalyzed by unsymmetrical bivalent dinuclear complexes are explored using DFT calculations in this report. Four basic catalyst-substrate binding modes are proposed, and two optional compartments for the location of the nucleophile-coordinated metal center are also considered. Five plausible mechanisms are examined in this computational study. Mechanisms 1, 2, and 3 employ an unsymmetrical dizinc complex. All three mechanisms are based on concerted SN2 addition-substitution pathways. Mechanism 1, which involves more electronegative oxygen atoms attached to the imine nitrogen atoms in the nucleophile-coordinated compartment, was found to be more competitive compared to the other two mechanisms. Mechanisms 4 and 5 are based on consideration of the substitution of the bivalent metal centers and the intrinsic flexibility of the ligand. Both mechanisms 4 and 5 are based on stepwise SN2-type reactions. Magnesium ions with hard base properties and more available coordination sites were found to be good candidates as a substitute in the M(II) dinuclear phosphatases. The reaction energy barriers for the more distorted complexes are lower than those of the less distorted complexes. The proper intermediate distance and a functional second coordination sphere lead to significant catalytic power in the reactions studied. More importantly, the mechanistic differences between the concerted and the stepwise pathways suggest that a better nucleophile with more available coordination sites (from either the metal centers or a functional second coordination sphere) favors concerted mechanisms for the reactions of interest. The results reported in the paper are consistent with and provide a reasonable interpretation for experimental observations in the literature. More importantly, our present results provide some practical suggestions for the selection of the metal centers and how to approach the design of a catalyst.
Persistent Identifierhttp://hdl.handle.net/10722/202572
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorZhang, Xen_US
dc.contributor.authorZhu, Yen_US
dc.contributor.authorZheng, Xen_US
dc.contributor.authorPhillips, DLen_US
dc.contributor.authorZhao, Cen_US
dc.date.accessioned2014-09-19T08:41:23Z-
dc.date.available2014-09-19T08:41:23Z-
dc.date.issued2014en_US
dc.identifier.citationInorganic Chemistry, 2014, v. 53, p. 3354-3361en_US
dc.identifier.urihttp://hdl.handle.net/10722/202572-
dc.description.abstractThe hydrolysis mechanisms of phosphor-monoester monoanions NPP(-) (p-nitrophenyl phosphate) catalyzed by unsymmetrical bivalent dinuclear complexes are explored using DFT calculations in this report. Four basic catalyst-substrate binding modes are proposed, and two optional compartments for the location of the nucleophile-coordinated metal center are also considered. Five plausible mechanisms are examined in this computational study. Mechanisms 1, 2, and 3 employ an unsymmetrical dizinc complex. All three mechanisms are based on concerted SN2 addition-substitution pathways. Mechanism 1, which involves more electronegative oxygen atoms attached to the imine nitrogen atoms in the nucleophile-coordinated compartment, was found to be more competitive compared to the other two mechanisms. Mechanisms 4 and 5 are based on consideration of the substitution of the bivalent metal centers and the intrinsic flexibility of the ligand. Both mechanisms 4 and 5 are based on stepwise SN2-type reactions. Magnesium ions with hard base properties and more available coordination sites were found to be good candidates as a substitute in the M(II) dinuclear phosphatases. The reaction energy barriers for the more distorted complexes are lower than those of the less distorted complexes. The proper intermediate distance and a functional second coordination sphere lead to significant catalytic power in the reactions studied. More importantly, the mechanistic differences between the concerted and the stepwise pathways suggest that a better nucleophile with more available coordination sites (from either the metal centers or a functional second coordination sphere) favors concerted mechanisms for the reactions of interest. The results reported in the paper are consistent with and provide a reasonable interpretation for experimental observations in the literature. More importantly, our present results provide some practical suggestions for the selection of the metal centers and how to approach the design of a catalyst.en_US
dc.languageengen_US
dc.relation.ispartofInorganic Chemistryen_US
dc.titleMechanismic Investigation on the Cleavage of Phosphate Monoester Catalyzed by Unsymmetrical Macrocyclic Dinuclear Complexes: The Selection of Metal Centers and the Intrinsic Flexibility of the Liganden_US
dc.typeArticleen_US
dc.identifier.emailPhillips, DL: phillips@hku.hken_US
dc.identifier.authorityPhillips, DL=rp00770en_US
dc.identifier.doi10.1021/ic402717xen_US
dc.identifier.pmid24649877-
dc.identifier.hkuros237036en_US
dc.identifier.volume53en_US
dc.identifier.spage3354en_US
dc.identifier.epage3361en_US
dc.identifier.isiWOS:000334092500019-

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats