skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Molybdenum binding site models for the molybdenum cofactor. Synthesis, spectroscopic characterization, and EHMO analysis of (NBu[sup n][sub 4])Na[Mo(O[sub 2]CC(S)Ph[sub 2])[sub 3]]

Abstract

The reaction of the cis-dioxo Mo(VI) complex [MoO[sub 2](O[sub 2]CC(S)Ph[sub 2])[sub 2]][sup 2[minus]] (1), having two coordinated thiobenzilate ligands, with an excess of thiobenzilic acid yields the monomeric monooxo Mo(V) complex [MoO(O[sub 2]CC(S)Ph[sub 2])[sub 2]][sup [minus]] (2), which is stable under these acidic conditions. However, partial neutralization of the thiobenzilic acid results in the reduction of 2, which, once formed, slowly yields the non-oxo tris-chelate Mo(IV) species [Mo(O[sub 2]CC(S)Ph[sub 2])[sub 3]][sup 2[minus]] (3). The generation of such a monomeric Mo(V) intermediate mimics the redox behavior of molybdenum hydroxylase enzymes. The pH dependence of the above Mo(V)-Mo(IV) conversion reaction as well as its relationship to the molybdenum center in nitrate reductase is discussed. The Mo site in 3 was revealed to be trigonal prismatic by a previous X-ray structure study. This structure constitutes the first example of a trigonal-prismatic geometry in a Mo(IV) complex whose ligands have no extensive intraligand [pi]-conjugation. The electronic structure as well as the spectroscopic and electrochemical properties are analyzed in terms of extended Hueckel molecular orbital calculations which are consistent with previous molecular orbital calculations for tris(dithiolene) complexes. Compared to the case of the dithiolene complexes, a stabilization of the prismatic structure is observed in themore » present thiobenzilate complex (3) as a result of improved [sigma]- and [pi]-bonding interactions between the Mo(IV) center and the sulfurs of the thiobenzilate ligands. The role of the solid packing interactions is also considered. 33 refs., 5 figs.« less

Authors:
; ; ;  [1]
  1. Universitat de Valencia (Spain)
Publication Date:
OSTI Identifier:
6234788
Resource Type:
Journal Article
Journal Name:
Inorganic Chemistry; (United States)
Additional Journal Information:
Journal Volume: 32:10; Journal ID: ISSN 0020-1669
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 59 BASIC BIOLOGICAL SCIENCES; MOLYBDENUM COMPLEXES; ELECTRONIC STRUCTURE; MOLECULAR STRUCTURE; BONDING; CHEMICAL PREPARATION; ENZYMES; MATHEMATICAL MODELS; MOLECULAR ORBITAL METHOD; ORGANIC ACIDS; ORGANIC SULFUR COMPOUNDS; PH VALUE; REDUCTION; STABILIZATION; CALCULATION METHODS; CHEMICAL REACTIONS; COMPLEXES; FABRICATION; JOINING; ORGANIC COMPOUNDS; PROTEINS; SYNTHESIS; TRANSITION ELEMENT COMPLEXES; 400201* - Chemical & Physicochemical Properties; 550200 - Biochemistry

Citation Formats

Cervilla, A, Ramirez, J A, Llopis, E, and Palanca, P. Molybdenum binding site models for the molybdenum cofactor. Synthesis, spectroscopic characterization, and EHMO analysis of (NBu[sup n][sub 4])Na[Mo(O[sub 2]CC(S)Ph[sub 2])[sub 3]]. United States: N. p., 1993. Web. doi:10.1021/ic00062a034.
Cervilla, A, Ramirez, J A, Llopis, E, & Palanca, P. Molybdenum binding site models for the molybdenum cofactor. Synthesis, spectroscopic characterization, and EHMO analysis of (NBu[sup n][sub 4])Na[Mo(O[sub 2]CC(S)Ph[sub 2])[sub 3]]. United States. https://doi.org/10.1021/ic00062a034
Cervilla, A, Ramirez, J A, Llopis, E, and Palanca, P. Wed . "Molybdenum binding site models for the molybdenum cofactor. Synthesis, spectroscopic characterization, and EHMO analysis of (NBu[sup n][sub 4])Na[Mo(O[sub 2]CC(S)Ph[sub 2])[sub 3]]". United States. https://doi.org/10.1021/ic00062a034.
@article{osti_6234788,
title = {Molybdenum binding site models for the molybdenum cofactor. Synthesis, spectroscopic characterization, and EHMO analysis of (NBu[sup n][sub 4])Na[Mo(O[sub 2]CC(S)Ph[sub 2])[sub 3]]},
author = {Cervilla, A and Ramirez, J A and Llopis, E and Palanca, P},
abstractNote = {The reaction of the cis-dioxo Mo(VI) complex [MoO[sub 2](O[sub 2]CC(S)Ph[sub 2])[sub 2]][sup 2[minus]] (1), having two coordinated thiobenzilate ligands, with an excess of thiobenzilic acid yields the monomeric monooxo Mo(V) complex [MoO(O[sub 2]CC(S)Ph[sub 2])[sub 2]][sup [minus]] (2), which is stable under these acidic conditions. However, partial neutralization of the thiobenzilic acid results in the reduction of 2, which, once formed, slowly yields the non-oxo tris-chelate Mo(IV) species [Mo(O[sub 2]CC(S)Ph[sub 2])[sub 3]][sup 2[minus]] (3). The generation of such a monomeric Mo(V) intermediate mimics the redox behavior of molybdenum hydroxylase enzymes. The pH dependence of the above Mo(V)-Mo(IV) conversion reaction as well as its relationship to the molybdenum center in nitrate reductase is discussed. The Mo site in 3 was revealed to be trigonal prismatic by a previous X-ray structure study. This structure constitutes the first example of a trigonal-prismatic geometry in a Mo(IV) complex whose ligands have no extensive intraligand [pi]-conjugation. The electronic structure as well as the spectroscopic and electrochemical properties are analyzed in terms of extended Hueckel molecular orbital calculations which are consistent with previous molecular orbital calculations for tris(dithiolene) complexes. Compared to the case of the dithiolene complexes, a stabilization of the prismatic structure is observed in the present thiobenzilate complex (3) as a result of improved [sigma]- and [pi]-bonding interactions between the Mo(IV) center and the sulfurs of the thiobenzilate ligands. The role of the solid packing interactions is also considered. 33 refs., 5 figs.},
doi = {10.1021/ic00062a034},
url = {https://www.osti.gov/biblio/6234788}, journal = {Inorganic Chemistry; (United States)},
issn = {0020-1669},
number = ,
volume = 32:10,
place = {United States},
year = {1993},
month = {5}
}