Synthesis, electrochemistry, and spectroscopic properties of six-coordinate monooxomolybdenum(VI) complexes containing tridentate Schiff base and bidentate catecholate ligands. Crystal and molecular structure of (N-salicylidene-2-aminophenolato)(naphthalene-2,3-diolato)oxomolybdenum(VI)

Journal Article · Wed Nov 02 04:00:00 EST 1988 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00295a014· OSTI ID:6236654

Mondal, J U; Schultz, F A; Brennan, T D; Scheidt, W R

Six-coordinate monooxomolybdenum(VI) complexes, MoO(cat)(Sap), where Sap/sup 2 -/ = the Schiff base dianion N-salicylidene-2-aminophenolate and cat/sup 2 -/ = catecholate Cat/sup 2 -/, naphthalene-2,3-diolate (Naphcat/sup 2 -/), or 3,5-di-tert-butylcatecholate (DTBcat/sup 2 -/), are prepared by reacting the Mo(VI) dimer. (MoO/sub 2/(Sap))/sub 2/, with the appropriate catechol. The products are characterized by cyclic voltammetry, mass spectrometry, and uv/vis, ir, and /sup 95/Mo NMR spectroscopy. The MoO(cat)(Sap) complexes represent the first examples of a mononuclear MoO/sup 4 +/ center with a coordination number of six. The crystal structure of the MoO-(Naphcat)(Sap) derivative is reported, confirming the six-coordinate, distorted octahedrla environment about Mo(VI). Bond angles in the coordination group deviate from the ideal value of 90/degrees/ as a consequence of the ligand bite constraints and because all four O-Mo-O angles involving the terminal oxo ligand are larger than the ideal 90/degrees/ value. MoO(cat)(Sap) complexes undergo reversible one-electronic reduction at -0.5 to -0.7 V versus Fc /sup +/0/ followed by irreversible one-electron reduction at -1.6 to -1.9 V. Reversible MoO/sup 4 +//MoO/sup 3 +/ electrochemistry is attributed to the fact that the Mo d/sub xy/orbital of MoO(cat)(Sap) can be singly occupied upon reduction to Mo(V) without unfavorable interaction with the four bonds in its equatorial plane. This contrasts with the irreversible electrochemical behavior of seven-coordinate MoO/sup 4 +/ complexes, which contain five such bonds. The /sup 95/Mo NMR chemical shift of MoO(Naphcat)(Sap) is +385 ppM versus external molybdate; this value is highly deshielded with respect to seven-coordinate MoO/sup 4 +/ and six-coordinate MoO/sub 2//sup 2 +/ complexes with O and N donors. 35 references, 4 figures, 5 tables.

• Research Organization: Florida Atlantic Univ., Boca Raton (USA)
• OSTI ID: 6236654
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 27:22; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
AROMATICS
COMPLEXES
CONDENSED AROMATICS
DATA
DEVELOPERS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HYDROCARBONS
HYDROXY COMPOUNDS
IMINES
INFORMATION
INFRARED SPECTRA
INTERMEDIATE MASS NUCLEI
ISOTOPES
MOLYBDENUM 95
MOLYBDENUM COMPLEXES
MOLYBDENUM ISOTOPES
NAPHTHALENE
NMR SPECTRA
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHENOLS
POLYPHENOLS
PYROCATECHOL
SCHIFF BASES
SPECTRA
STABLE ISOTOPES
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
ULTRAVIOLET SPECTRA