Unique 2:1 Complex with a trans-Chelating Bis-Pyridine Ligand

Abstract

The trans-chelating ligand 1,2-bis(2‘-pyridylethynyl)benzene (1) was prepared in a single step by a Sonogashira cross-coupling reaction. Treatment of 1 with trans-bis(acetonitrile)palladium chloride provides the complex [Pd(1)Cl2] while treatment with tetrakis(acetonitrile)palladium(II) tetrafluoroborate provides the 2:1 complex [Pd(1)2](BF4]2. The structural, spectroscopic, and thermal properties of 1 and its Pd(II) complexes are examined.

Synthesis, Structure, and Complexation of an S‐Shaped Double Azahelicene with Inner‐Edge Nitrogen Atoms

“…The validity of the postulated structure of the ion pair (16)c an be discussed on the basis of how closely the expected EXFAS absorption spectrum of the palladium complex matches the experimentallyo bserved one. The structure of [(dl-1)-Pd] 2 + was optimized using DFT calculations (PBE0-D3BJ functional, def2-TZVP for Pd and N, def2-SVP for O, C, and H).…”

“…Then, we surveyed the optimal amounto fo xidantf or the coupling reaction (entries [11][12][13], and discovered that ac ombination of 3.0 equivalents of AgOAc and 4.0 equivalents of DMSO delivered the best results( entry 11). Undert he optimized conditions, various 1-aza [5]helicenes (4b-e)w ere synthesized in excellent yield, regardless of the nature of the substituent in 3 (entries [14][15][16][17].…”

“…Although single crystalso ft he resulting palladium complex suitable for single crystal X-ray diffraction analysisw ere not obtained,t he palladium complex consistingo ft he ion pair [(dl-1) (16)w as unequivocally determined by elemental analysis,I CP-MS, XPS, XAFS (including extended X-ray absorption fine structure (EXAFS)), DR UV/Vis, and FIR absorption spectroscopy.T he complex (16)w as formed by ad isproportionation between a trans-chelating (dl-1)•PdCl 2 complex and PdCl 2 (Scheme 5). [16] The experimental details that led us to this conclusion are described below.I nitially,w ec arriedo ut an elementala nalysis (for C, H, N, and Cl) and ICP-MS analysis( for Pd) ( Table 2). Initially,w ea ssumed the formation of a1 :1 complex between dl-1 and PdCl 2 .H owever,e specially the experimentally obtained ratio between chlorine and palladium deviated substantially from the theoretically expectedv alue ( Table 2).…”

Unique Metal‐Diyne, ‐Enyne, and ‐Enediyne Complexes: Part of the Remarkably Diverse World of Metal‐Alkyne Chemistry

“…The ability of this general suite of ligands to potentially build bridging structures, especially the rigid 3-pyridyl and quinoline R-groups constructs, coupled with the rigid 2-pyridyl trans-binding ligand reported by Thummel and co-workers (556), has contributed to the development of dimeric (557)(558)(559) and higher order (560-567) metal-containing architectures (Fig. 31).…”

Complexation of silver(I) cation by a series of heterosubstituted dipyridyl ligands

“…We earlier reported the design and synthesis of a simple trans coordinating ligand, 1,2-bis(2 0 -pyridylethynyl) benzene (1 in Scheme 1A), that was particularly well suited for the coordination of silver(I) and palladium(II) cation [1,2]. We modeled the planar conformation of the ligand as shown in Scheme 1 and noted that this conformation would position the pyridyl N-atoms in the ideal position at 4.3 Å apart to coordinate transition metal cations like silver(I) that favor linear coordination geometry [3].…”