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The First Crystal and Molecular Structure of a syn ‐Acetato‐Bridged Dinuclear Cyclometallated Complex [Pd{2,3,4‐(MeO) 3 C 6 HC(H)=NCH 2 CH 2 OH}(μ‐OAc)] 2
Author(s) -
Fernández Alberto,
VázquezGarcía Digna,
Fernández Jesús J.,
LópezTorres Margarita,
Suárez Antonio,
CastroJuiz Samuel,
Vila José M.
Publication year - 2002
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(200209)2002:9<2389::aid-ejic2389>3.0.co;2-m
Subject(s) - chemistry , imine , ligand (biochemistry) , palladium , substituent , medicinal chemistry , crystal structure , stereochemistry , chloroform , crystallography , catalysis , organic chemistry , biochemistry , receptor
Treatment of the Schiff base ligands 2,3,4‐(MeO) 3 C 6 H 2 C(H)=NR (R = CH 2 CH 2 OH, 1 ; R = Me, 17 ; R = Et, 18 ; R = Pr, 19 ; R = t Bu, 20 ) with palladium( II ) acetate in toluene gave the dinuclear cyclometallated complexes [Pd{2,3,4‐(MeO) 3 C 6 HC(H)=NR}(μ‐O 2 CMe)] 2 (R = CH 2 CH 2 OH, 2 ; R = Me, 21 ; R = Et, 22 ; R = Pr, 23 ; R = t Bu, 24 ), with the ligand bonded to the palladium atom through the imine nitrogen and the C6 carbon atoms. The 1 H and 13 C{ 1 H} NMR spectra of the complexes showed the presence of the anti and syn isomers in solution. The anti / syn ratio varies with the solvent and the nature of the imine nitrogen substituent R. Complex 24 with the bulky t Bu group showed a 28:1 ratio in chloroform whilst the less bulky substituted complexes showed lower ratios. The X‐ray crystal structure of the syn isomer of complex 2 is described. Reaction of the acetato‐bridged complex 2 with PPh 3 gave the mononuclear complex 4 , in a bridge‐splitting reaction. Reaction of 2 with the diphosphanes dppm, dppp and dppb in a 1:1 molar ratio gave the dinuclear cyclometallated complexes 5 , 6 and 7 , respectively. Treatment of 2 with an aqueous solution of sodium chloride gave the chloro‐bridged complex 3 . Treatment of the cyclometallated chloro‐bridged complex 3 with PPh 3 in acetone yielded the mononuclear complex 8 , and reaction of 3 with silver triflate gave the cyclometallated complex 9 , with the palladium atom bonded to four different atoms C, N, O and P. Treatment of 3 with the tertiary diphosphanes dppp, dppb and dppf, in a 1:1 molar ratio gave the dinuclear complexes 10 , 11 and 12 , respectively, with terminal chloride ligands. However, reaction of 3 with the small “bite” diphosphane dppm gave 13 , with a bridging chloride ligand. Reaction of 11 with silver triflate in acetone gave the new dinuclear complex 14 , with the Schiff base ligand as [C,N,O] terdentate. Reaction of 3 with the diphosphane dppe in a 1:2 molar ratio, and silver perchlorate, gave the mononuclear complex 15 . Treatment of 3 with the triphosphane bis(2‐diphenylphosphanylethyl)phenylphosphane in a 1:2 molar ratio, followed by treatment with sodium perchlorate, gave 16 , in which the palladium atom was bonded to the triphosphane through the three phosphorus atoms. The X‐ray crystal structures of complexes 8 , 9 , 15 and 16 are also reported. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)