Metal-Mediated Controllable Creation of Secondary, Tertiary, and Quaternary Carbon Centers: A Powerful Strategy for the Synthesis of Iron, Cobalt, and Copper Complexes with in Situ Generated Substituted 1-Pyridineimidazo[1,5-a]pyridine Ligands

Abstract

An efficient strategy for the synthesis of a wide variety of coordination complexes has been developed. The synthetic protocol involves a solvothermal in situ metal-ligand reaction of picolinaldehyde, ammonium acetate, and transition-metal ions, leading to the generation of 12 coordination complexes supported by a novel class of substituted 1-pyridineimidazo[1,5-a]pyridine ligands (L1-L5). The ligands L1-L5 were afforded by metal-mediated controllable conversion of the aldehyde group of picolialdehyde into a ketone and secondary, tertiary, and quaternary carbon centers, respectively. Complexes of various nuclearities were obtained: from mono-, di-, and tetranuclear to 1D chain polymers. The structures of the in situ formed complexes could be controlled rationally via the choice of appropriate starting materials and tuning of the ratio of the starting materials. The plausible mechanisms for the formation of the ligands L1-L5 were proposed.

Tracking the Process of a Solvothermal Domino Reaction Leading to a Stable Triheteroarylmethyl Radical: A Combined Crystallographic and Mass‐Spectrometric Study

“…Ligand L1 coordinates with FeCl 3 ⋅6 H 2 O to give intermediate [Fe II ( L1 ) 2 Cl] + (step i). The self‐condensation of the coordinated L1 to an imine (ii–iv) is followed by intramolecular cyclization (v), aromatization (vi), and dissociation (vii) to give 3 . Then, 3 could react with formaldehyde (viii) derived from methanol to give a primary alcohol (ix; Figure b).…”

Temperature‐induced formation of two dinuclear dysprosium complexes with different magnetic properties

“…In recent years, hydrothermal/solvothermal technology has gradually become an important synthetic means, and a directional construction of new organic frameworks, coordination polymers and coordination molecular clusters has been achieved . Under solvothermal conditions, owing to the effects of temperature and pressure, certain metal ions with strong catalytic ability can further catalyze the reaction of the starting ligand by coordinating under in situ conditions, which will produce several organic compounds that are difficult to build via traditional organic synthesis . In addition, the newly produced ligands can further participate in the assembly to form metal complexes with novel structures and excellent physical and chemical properties .…”

“…In addition, the newly produced ligands can further participate in the assembly to form metal complexes with novel structures and excellent physical and chemical properties . Therefore, solvothermal in situ metal/ligand reactions are called bridges between inorganic and organic reactions . While additional examples of organic ligands involved in coordination during the formation of complexes have been found, these examples are mostly involved in the formation of 3d metal complexes .…”

“…Therefore, solvothermal in situ metal/ligand reactions are called bridges between inorganic and organic reactions . While additional examples of organic ligands involved in coordination during the formation of complexes have been found, these examples are mostly involved in the formation of 3d metal complexes . Lanthanide metal ions have difficulty undergoing complex in situ ligand reactions during the formation of lanthanide complexes owing to their strong coordination ability, strong selectivity of coordination atoms, and complex and varied coordination configurations .…”

3‐(Pyridin‐2‐yl)imidazo[1,5‐a]pyridine (Pyridylindolizine) as Ligand in Complexes of Transition and Main‐Group Metals

“…[9] Shortly after the publication of our work in the preparation of Py-indz mediated by manganese, the preparation of substituted 1-pyridineimidazo[1,5-a]pyridine ligands was reported. [10] There are only a few examples of the use of 3-(pyridin-2-yl)imidazo[1,5-a]pyridines as ligands in Cu II , [11] Ni II , [12] V V , [13] Ir III , [14] and Re I complexes, [15] or analogues of Cd II , [16] to prepare boron complexes [17] or involved in a catalytic process to synthesize N-heterocycles. [18] Some related derivatives of 3-(pyridin-2-yl)imidazo[1,2-a]pyridine have been used in situ to regulate the metal-induced aggregation of amyloid-β.…”