Premium
A family of thioxanthato ruthenium and osmium aryls
Author(s) -
Chattopadhyay Swarup,
Panda Bikash Kumar,
Ghosh Kaushik,
Chakravorty Animesh
Publication year - 2002
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1560/c80w-66cr-qhhl-gyu5
Subject(s) - chemistry , tautomer , steric effects , ligand (biochemistry) , ruthenium , osmium , aldimine , chelation , ring (chemistry) , medicinal chemistry , imine , stereochemistry , dihedral angle , carbanion , crystallography , hydrogen bond , molecule , catalysis , inorganic chemistry , organic chemistry , biochemistry , receptor
The title complexes of type M(RL 2 )(PPh 3 ) 2 (CO)(S 2 CSEt) ( 2a : M = Ru; 2b : M = Os) have been synthesized in excellent yields by reacting M(RL 1 )(PPh 3 ) 2 (CO)X ( 1a : M = Ru, × = Cl; 1b : M = Os, × = Br) with potassium ethyl thioxanthate and have been characterized with the help of spectral and electrochemical data. The RL 2 ligand in 2 is the imine‐phenol tautomer of N‐C 6 H 4 R( p )‐4‐methylsalicylaldimine (R = Me, MeO, Cl) coordinated at the carbanionic‐C2 atom only while RL 1 in 1 is the iminium‐phenolato tautomer chelated via carbanionic‐C2 and phenolato‐O atoms. The synthetic reaction is thus attended with tautomerization of the Schiff base ligand. It is also associated with a rotation of the ligand by ˜180° around the M–C bond in order to exclude steric repulsion. These features have been revealed by structure determination of 2a (R = Me). The metallated aldimine ring is found to be highly noncoplanar (dihedral angle ˜40°) with the thioxanthate chelate ring due to steric repulsion originating from the relatively large size of the sulfur atom. This phenomenon, which is absent in both the precursor 1 (R = Me) and in the carboxylate analogue Ru(MeL 2 )(PPh 3 ) 2 (CO)(O 2 CMe), 7 , has distinctive effects on bond parameters of 2a (R = Me). Thus the two Ru–P bonds in 2a (R = Me) differ in length by as much as 0.06 Å. The thioxanthate 2 is thermodynamically more stable than the precursor 1 as well as the carboxylate 7 . Accordingly, both of these are irreversibly transformed to 2a (R = Me) upon treatment with thioxanthate.