Synthesis and NMR characterization of the novel mixed-ligand Pt(II) complexes cis- and trans-Pt(Ypy)(pyrimidine)Cl2 and trans,trans-Cl2(Ypy)Pt(μ-pyrimidine)Pt(Ypy)Cl2 (Ypy=pyridine derivative)

Structural correlations for 1H, 13C and 15N NMR coordination shifts in Au(III), Pd(II) and Pt(II) chloride complexes with lutidines and collidine

“…On the contrary, the opposite Δ H( ortho ) > Δ H( meta , para ) relation was noted for Pt(II)‐trichloride anions with 2,4lut or 2,6lut ([Pt(LUT)Cl 3 ] − )8; Pt(II)‐dichloride complexes with pyrazine or pyrimidine and lutidines or collidine ( trans ‐/ cis ‐[PtL(pyrazine)Cl 2 ], trans ‐/ cis ‐[PtL(pyrimidine)Cl 2 ], [( trans ‐PtLCl 2 ) 2 (µ‐pyrazine)], [( trans ‐PtLCl 2 ) 2 (µ‐pyrimidine)])30, 31; Pt(II)‐diodide compounds with 2,4‐lut or 3,5‐lut ( trans ‐/ cis ‐[Pt(LUT) 2 I 2 ]) 7. This Δ H( ortho ) > Δ H( meta , para ) dependency occurred also for Pt(II)‐dinitrate, ‐dihydroxo and ‐diaqua complexes with 2,4lut, while, surprisingly, that of Δ H( ortho ) < Δ H( meta , para ) for those with 3,5lut ( trans ‐/ cis ‐[Pt(LUT) 2 (ONO 2 ) 2 ], cis ‐[Pt(LUT) 2 (OD) 2 ] and cis ‐[Pt(LUT) 2 (D 2 O) 2 ] 2+ ) 32, 33.…”

“…Such deshielding of heterocyclic carbons (by maximum ca 10 ppm) was already observed in some other complexes with lutidines or collidine: [AuLCl], [29] [PtLCl 3 ] − , [9] trans-/cis-[PtL(pyrazine)Cl 2 ] and [(trans-PtLCl 2 ) 2 (µ-pyrazine)], [30] trans-/cis-[PtL(pyrimidine) Cl 2 ] and [(trans-PtLCl 2 ) 2 (µ-pyrimidine)], [31] trans-/cis-[Pt(LUT) 2 I 2 ], [7] trans-/cis-[Pt(LUT) 2 (ONO 2 ) 2 ], [32] (Table S3, supporting information). (Fig.…”

“…On the contrary, the opposite H(ortho) > [30,31] ; Pt(II)-diodide compounds with 2,4-lut or 3,5-lut (trans-/cis-[Pt(LUT) 2 I 2 ]). [7] 2+ ).…”

“…[7,8,26,30 -33] No literature 1 H NMR data concern Pd(II) and Pt(II) complexes of analogous structure, while they are available for some pairs of the corresponding Pt(II) isomers. Thus, the trans-→ cis-geometry could result in either increase or decrease of the deshielding effect for ortho-protons, as observed during trans-→ cis-[Pt(LUT)(pyrazine)Cl 2 ], [30] [30,31] as well as 3,5lut → 2,4lut for trans-/cis-[Pt(LUT) 2 I 2 ], [7] trans-/cis-[Pt(LUT) 2 (ONO 2 ) 2 ], [32] [33] The comparison of 1 H NMR spectra for Au(III), Pd(II) and Pt(II) chloride complexes with various tri-, di-and monomethylpyridines exhibits the enhancement of the deshielding effect for orthopositioned methyl groups with the increase of their number in these positions, i.e. in the series: L = 2pic or 2,4lut [8,13,29 -31] The proton deshielding was observed also upon AuCl 3 or PdCl 2 coordination of some 2,6lut analogues (Table S2, supporting information).…”

Gold(III) complexes with phenazine and quinoxaline: The role of molecular symmetry in intra- and intermolecular interactions

“…Five-membered azoles are p-excessive donor ligands and deprotonation of acidic NH groups results in anionic ligands that also form stable complexes [11][12][13]. On the other hand, the six-membered azines are p-electron deficient, being able to accept electron density from metal centers in metal-ligand backbonding [14,15]. Introduction of further heteroatoms into either the azine or azole ring systems, as well as the incorporation of two or more aromatic nitrogen heterocycles into a molecule, provides a broad spectrum of ligands with very different electronic and coordination properties [5].…”