Vanadocene complexes of amino acids containing secondary amino group: the first evidence of O,O-bonded carboxylic group to vanadocene(IV) moiety.

Abstract Reaction of vanadocene dichlorides (Cp 2 VCl 2 and (η 5 -C 5 H 4 Me) 2 VCl 2 ) with amino acids containing secondary amino groups gives three types of complexes: a) compounds with N,O-bonded amino acid, b) O-bonded amino acids and c) O,O-bonded amino acid. The complexes with N,O-bonded amino acid and O-bonded amino acids were observed in the case of l -proline and N -methylglycine (NMG). Reactions with N -phenylglycine (NPG) give O,O-chelates as the sole products. All three types of the complexes were characterized by spectroscopic methods. Structures of [(η 5 -C 5 H 4 Me) 2 V( O -Pro)][BPh 4 ], [Cp 2 V( O -Pro) 2 ][PF 6 ] 2 , [Cp 2 V( N , O -NMG)][BPh 4 ]·MeOH, [(η 5 -C 5 H 4 Me) 2 V( N , O -NMG)][BPh 4 ]·MeOH, [Cp 2 V( O -NMG) 2 ][Cl] 2 ·2H 2 O, [(η 5 -C 5 H 4 Me) 2 V( O -NMG) 2 ][Cl] 2 ·H 2 O and [(η 5 -C 5 H 4 Me) 2 V( O , O -NPG)][BPh 4 ] were determined by X-ray crystallography.