Six-membered cyclopalladated N, N′, N″-triarylguanidines, [{κ2(C, N)Pd}2(μ-OAc)(μ-Pz)], [κ2(C, N)Pd(μ-Pz)]2 and a novel [AgNO3⊂{{κ2(C, N)Pd}2(μ-NO3)(μ-Pz)}]: Syntheses, reactivity studies, structural aspects, and solution behavior. (15th October 2016)

• Record Type: Journal Article
• Authors: Agarwal, Pallavi; Thomas, Jisha Mary; Sivasankar, Chinnappan; Nethaji, Munirathinam; Thirupathi, Natesan
• Is Part Of: Polyhedron. Volume 117(2016)
• Page Start: 679
• Page End: 694
• Publication Date: 2016-10-15
• Subjects: Pyrazoles -- Conformers -- Fluxional behavior -- Palladium–silver complex -- Guanidine; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2016.07.008
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: Cyclopalladated N, N ′, N ″-tri(2-tolyl)guanidine, 6 encapsulates AgNO3 inside a cavity to afford complex12 due to stabilization attained through Pd → Ag (d 8 → d 10 ) and Ag- η 1 arene (soft–soft) interactions. Abstract: Six-membered cyclopalladated N, N ′, N ″-triarylguanidines, [{ κ 2 ( C, N )Pd}2 ( μ- OAc)( μ -Pz)] (1 –4 ), [ κ 2 ( C, N )Pd( μ -Pz)]2 (5 –11 ), and [AgNO3 ⊂{{ κ 2 ( C, N )Pd}2 ( μ- NO3 )( μ- Pz)}] (12 ) have been isolated in good yields and characterized by micro-analytical, IR, and NMR ( 1 H, 19 F, and 13 C) spectroscopic techniques. Molecular structures of ten complexes were determined by SCXRD, which revealed cisoid in–out (1 –4 ), transoid out–out (5, 6, 8 and11 ), transoid in–in (7 ) and cisoid (12 ) conformations. VT 1 H NMR spectra of1 revealed the presence of cisoid in–in as the major species and an equilibrating mixture of cisoid in–out and cisoid out–out as the minor species in solution and this was verified by DFT calculations. In solution, 4 indicated the presence of a mixture of cisoid, and transoid conformers, [ κ 3 ( C, N, O )Pd(OAc)], and [ κ 2 ( C, N )Pd( κ 2 O, O ′ - OAc)] (VT 1 H NMR), and a mixture of three conformers of each cisoid and transoid, and [ κ 3 ( C, N, O )Pd(Pz)] (VT 19 F NMR). Palladacycles5 and10 revealed the presence of a mixture of four and five species, respectively in solution and these species are a mixture of cisoid and transoid conformers as revealed by VT 1 H NMR. Factors that dictate the solid state conformations and number and nature of solution species of the new complexes are outlined.