Influence of steric effect on the structural aspects of N,N `,N `'-triarylguanidine derived six-membered C,N] palladacycles

Gopi, Kanniyappan and Saxena, Priya and Nethaji, Munirathinam and Thirupathi, Natesan (2013) Influence of steric effect on the structural aspects of N,N `,N `'-triarylguanidine derived six-membered C,N] palladacycles. In: Polyhedron, 52 (SI). pp. 1041-1052.

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Abstract

Guanidine derived six-membered C,N] palladacycles of the types (C,N)Pd(mu-OC(O)R)](2) (1a-d), (C,N)Pd(mu-Br)](2) (2a,b), cis-(C,N)PdBr(L)] (3a-d, 4, and 5), and ring contracted guanidine derived five-membered C,N] palladacycle, (C,N)PdBr(C NXy)] (6) were prepared in high yield following the established methods with a view aimed at understanding the influence of the substituents on the aryl rings of the guanidine upon the solid state structure and solution behaviour of palladacycles. Palladacycles were characterised by microanalytical, IR, NMR and mass spectral data. The molecular structures of 1a, 1c, 2a, 2b, 3a, 3c, 3d, and 4-6 were determined by single crystal X-ray diffraction data. Palladacycles 1a and 1c were shown to exist as a dimer in transoid in-in conformation in the solid state but as a mixture of a dimer in major proportion and a monomer (kappa(2)-O,O'-OAc) in solution as deduced from H-1 NMR data. Palladacycles 2a and 2b were shown to exist as a dimer in transoid conformation in the solid state but the former was shown to exist as a mixture of a dimer and presumably a trimer in solution as revealed by a variable temperature H-1 NMR data in conjunction with ESI-MS data. The cis configuration around the palladium atom in 3a, 3c, and 3d was ascribed to steric influence of the aryl moiety of =NAr unit and that in 4-6 was ascribed to antisymbiosis. The solution behaviour of 3d was studied by a variable concentration (VC) H-1 NMR data.

Item Type:	Journal Article
Publication:	Polyhedron
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Guanidine; Palladacycle; Conformer; Lewis Base; n-pi Conjugation
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	26 Jun 2013 10:09
Last Modified:	26 Jun 2013 10:09
URI:	http://eprints.iisc.ac.in/id/eprint/46760

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