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Dioxo‐ and Oxovanadium(V) Complexes of Biomimetic Hydrazone ONO Donor Ligands: Synthesis, Characterisation, and Reactivity
Author(s) -
Maurya Mannar R.,
Khurana Shilpa,
Schulzke Carola,
Rehder Dieter
Publication year - 2001
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200103)2001:3<779::aid-ejic779>3.0.co;2-#
Subject(s) - chemistry , hydrazone , reactivity (psychology) , combinatorial chemistry , stereochemistry , medicinal chemistry , medicine , alternative medicine , pathology
The dioxovanadium(V) complexes M[VO 2 (L) solv ] ( 2 , 5 , 6 ) have been isolated along with dimeric, oxo‐bridged monooxovanadium complexes with the formula [{VOL} 2 µ‐O] ( 1 , 4 ), and characterised by their spectral and thermogravimetric properties and reactivity patterns. H 2 L is the hydrazone H 2 {(R‐sal)‐iNH} [sal derives from salicylaldehyde (R = H) or p ‐Cl‐salicylaldehyde (R = Cl)] or H 2 hap‐iNH, where hap is the o ‐hydroxyacetophenone moiety, and iNH stands for isonicotinic acid hydrazide. In the isolated potassium (M = K) complexes 2a , 5 and 6 , solv is a water molecule, which was exchanged for methanol or DMSO in the respective solutions as shown by 51 V NMR. Treatment of the dimeric ( 1 and 4 ) or anionic complexes ( 2a and 5) with H 2 O 2 yielded (unstable) oxoperoxovanadium complexes K[VO(O 2 )L] ( 7 , 8 ). Acidification of 1 and 4 afforded oxohydroxo complexes. When compound 2a is dissolved in methanol, it is partly deoxygenated to form [VO(OMe)(HOMe)L] ( 9 ), the crystal and molecular structures of which have been determined, confirming the ONO binding mode of L in its enolate form.