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Chlorination of Platinum‐Bound Salicylaldoxime. The First Example of a Structurally Characterized Monodentate Salicylaldoxime‐Type Ligand
Author(s) -
Kaplan Savelii F.,
Kukushkin Vadim Yu.,
Shova Sergiu,
Suwinska Kinga,
Wagner Gabriele,
Pombeiro Armando J. L.
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(200104)2001:4<1031::aid-ejic1031>3.0.co;2-d
Subject(s) - chemistry , platinum , denticity , ligand (biochemistry) , intramolecular force , medicinal chemistry , benzene , oxidative addition , crystallography , nuclear magnetic resonance spectroscopy , stereochemistry , proton nmr , hydrogen bond , molecule , crystal structure , organic chemistry , biochemistry , receptor , catalysis
The reaction of K 2 [PtCl 4 ] and salicylaldoxime in an approximate 1:2 molar ratio in water resulted in the isolation of a mixture of four compounds from which [Pt( o ‐OC 6 H 4 CH=NOH) 2 ] ( 1 ) and [PtCl(OC 6 H 4 CH=NOH)(HOC 6 H 4 CH=NOH)] ( 2 ) were isolated, whereas the other two were shown to be unstable and decomposed both in solution and on SiO 2 during chromatography. Chlorination of 1 and 2 with Cl 2 resulted in the oxidative addition of chlorine to the platinum(II) center and in the chlorination of the benzene ring, giving the platinum(IV) complexes [PtCl 2 (3,5,2‐Cl,Cl,OC 6 H 2 CH=NOH) 2 ] ( 3 ) and [PtCl 3 (3,5,2‐Cl,Cl,OC 6 H 2 CH=NOH)(3,5,2‐Cl,Cl,HOC 6 H 2 CH=NOH)] ( 5 ), respectively, containing commercially unavailable 3,5‐dichloro‐2‐hydroxybenzaldehye oxime. Alternatively, treatment of 1 with NOCl resulted only in the oxidation of the platinum(II) center to furnish [PtCl 2 ( o ‐OC 6 H 4 CH=NOH) 2 ] ( 4 ), whereas the benzene rings of salicylaldoximato ligands remained intact. All complexes were characterized by C, H, N, Cl and Pt elemental analyses, FAB + mass spectrometry, IR and 1 H, 13 C{ 1 H} and 195 Pt NMR spectroscopy. Compounds 1 , 3 and 5 were analyzed by X‐ray crystallography. In 1 , the salicylaldoximato ligands adopt a trans configuration and the hydrogen atoms of the OH groups are involved in intramolecular hydrogen bonding, forming five‐membered rings. In 3 , every molecule of the complex forms the repeating unit for a self‐assembly that produces infinite one‐dimensional polymeric chains directed along the z axis held by hydrogen bonds. The complex 5 represents the first example of a structurally characterized metal complex with a monodentate salicylaldoxime‐type ligand, although the conventional bidentate N,O ‐coordination mode is a classical topic in coordination chemistry.