Molecular conformation of di-2-pyridyl sulphide. A dipole moment, 1H nuclear magnetic resonance, and CNDO/2 study

Abstract

Di-2-pyridyl sulphide has been prepared and its electric dipole moment measured a t 25 and 45" (3.50 D, in benzene solution). The 250 MHz variable temperature pulsed Fourier transform l H n.m.r. spectrum has been also measured and analysed. Results of theoretical energy calculations (CN D0/2 type) together with the experimental data have been interpreted in terms of molecular solute conformations. It has been found that the molecule prefers a twisted conformation in which the ring planes are rotated ca. 36" out of the CSC plane. A fast interconversion between the three conformers that correspond to the possible relative orientations of the pyridine rings in this structure was found to occur in the solution state.OUR current interest in the study of the relationship Now if the symmetry and typical linear structure of the between the conformational properties and the chelating U022+ systems is considered,1° it clearly appears that ability of sulphur compounds containing pyridine knowledge of the conformational properties of the chelatrings 1-5 has prompted us to examine the conformation ing molecule is a potentially useful tool for the prediction of di-2-pyridyl sulphide. This molecule has been shown of the stereochemistry of the co-ordination compounds. to be a complexing agent for transition metals6-8 and, Previous investigations of the conformation of the more recently, for uranyl In these complexes, di-similar diphenyl sulphide molecule have been reported. 2-pyridyl sulphide acts as a bidentate ligand, co-ordin-These used the EHMO approach l1 and experimental ation Occurring Only through the two nitrogen atoms'

Restricted Phenyl Rotation in Pyridyl Thioether Ligands N,S‐Chelated to Congested Diiminoruthenium Cores

“…General Remarks: Di-2-pyridyl sulfide, [25] di-2-pyrimidyl sulfide, [19] 2-pyridylmethyl p-tolyl sulfide, [26] p-chlorophenyl 2-pyridylmethyl sulfide, [26] 2-pyridyl 2-pyridylmethyl sulfide, [26] [RuCl 2 (dps) 2 ]· 2H 2 O [15] and [RuCl 2 (dprs) 2 ]·2H 2 O [19] were prepared by published methods. Other reagents and solvents were used as received.…”

Structure of bis(2-pyridylthio-2-pyridinium) tetrachlorodioxouranate(VI)

“…on the basis of energy calculations for the nonprotonated molecule (Chachaty, Pappalardo & Scarlata, 1976). On the other hand, theoretical calculations (Galasso, De Alti & Bigotto, 1971) and molar Kerr constant studies (Aroney, Le Fevre & Saxby, 1963;Le Fevre & Saxby, 1966) predict for the diphenyl sulphide molecule a non-planar structure with angles of ca 42-48 ° between the phenyl ring planes because of the steric contact between ortho H atoms.…”

Bis[bis(2-pyridyl-N) sulfide]palladium(II) Bis(tetrafluoroborate)

“…Di-2-pyridyl sulfide (Chachaty et al, 1976) and [Pd(1,5-C8HI2)C12] (Drew & Doyle, 1972) were prepared according to published methods. All other reagents and solvents are commercial products.…”

“…Recently, some crystal structure determinations (Tresoldi et al, 1992;De Munno et al, 1993;Bruno et al, 1995) have shown that the chelate ring of coordinated flexible bipyridinelike ligands adopts a boat conformation in the solid state, while NMR studies have shown that these flexible ligands favour dynamic processes in solution (Tresoldi et al, 1991(Tresoldi et al, , 1992De Munno et al, 1993). Concerning dps and its derivatives, it is known that the free dps ligand adopts three planar (N,N-inside, N,N-outside, N-inside~N-outside) and several twisted conformations in the three states of matter (Chachaty, Pappalardo & Scarlata, 1976;Amato, Bandoli, Grassi, Pappalardo & Scarlata, 1989;Bombieri, Forsellini & Graziani, 1978;Colonna, Distefano, Galasso, Pappalardo & Scarlata, 1977) which may be present when dps is bonded to the metal as a chelate or bridging ligand. The route followed for the synthesis of the dicationic complexes [MII(dps)2](BF4)2 [M = Pd, (I), and Pt, (II)] is…”