Synthesis Of Transition Metal Carbonyl Complexes Based On Pyridine Imine Ligands And Their Catalytic Friedel-Crafts Acylation

The metal complexes containing schiff base play an important role in the transition metal coordination chemistry because of its easy preparation?good stability?diverse structure and diversity,especially in the biological ? functional materials and catalytic applications of concern,but the corresponding transition metal carbonyl complex reportedless.Since the N atoms in the pyridine imines contain lone pairs,they have strong coordination ability with the transition metals,and some of their complexes have played an important role in the application.In this paper,the reactivity of pyridine imine [C₅H₄N-2-C?H?=N-C₆H₄-R] with Ru₃?CO?₁₂ and Mo?CO?₆ was studied,eight kinds of dinuclear metal carbonyl ruthenium complexes and six kinds of mononuclear metal carbonyl molybdenum complexes were isolated.And the structure of seven kinds of metal carbonyl complexes was determined by X-ray single crystal diffractometer,and its structural characteristics were studied.The details are as follows:?1?The pyridine imines were studied [C₅H₄N-2-C?H?=N-C₆H₄-R] [R = H?1?;CH₃?2?;OMe?3?;CF₃?4?;Cl?5?;Br?6?;OH?7?;NH₂?8?],and then reacted with Ru₃?CO?₁₂ in toluene as solvent for 8 h.Eight kinds of dinuclear metal carbonyl ruthenium complexes were isolated { m-? ²-CH[?2-C₅H₄N??N-C₆H₅?]}₂Ru₂?CO?₄?m-CO??9??{ m-? ²-CH[?2-C₅H₄N??N-C₆H₄-4-CH₃?]}₂Ru₂?CO?₄?m-CO??10??{ m-? ²-CH[?2-C₅H₄N??N-C₆H₄-4-OMe?]}₂Ru₂?CO?₄?m-CO??11??{ m-? ²-CH[?2-C₅H₄N??N-C₆H₄-4-CF₃?]}₂Ru₂?CO?₄?m-CO??12??{ m-? ²-CH[?2-C₅H₄N??N-C₆H₄-4-Cl?]}₂Ru₂?CO?₄?m-CO??13??{ m-? ²-CH[?2-C₅H₄N??N-C₆H₄-4-Br?]}₂Ru₂?CO?₄?m-CO??14??{ m-? ²-CH[?2-C₅H₄N??N-C₆H₄-4-OH?]}₂Ru₂?CO?₄?m-CO??15??{m-?²-CH[?2-C₅H₄N??N-C₆H₄-4-NH₂?]}₂Ru₂?CO?₄?m-CO??16?,the composition and structure of compounds were characterized by IR?1H NMR?13C NMR and elemental analysis.The crystal structure of 9,12,13,14 metal carbonyl ruthenium complex was determined by X-ray single crystal diffractometer.The single crystal structure shows that: C-C bond coupling occurs in the two molecules of the ligand molecule,the imine C = N functional group,Thefour N atoms in the bridge chain are coordinated with two Ru atoms simultaneously with the a N nitrogen bridge of the triple electron donor,and the m2-N atom of each pyridine ring is coordinated with a Ru atom,Thus chelating the formation of two five-membered ring structure;The molecular weight of the Ru-Ru bond is 2.856?11??,2.858?5??,2.868?5??,2.866?9??.The four groups of complexes are monoclinic systems,of which 9 and 12 two single crystal space group P21/n,13 and 14 two single crystal space group C2/c.?2?The pyridine imines [C₅H₄N-2-C?H?=N-C₆H₄-R] [R = H?1?;CH₃?2?;OMe?3?;CF₃?4?;Cl?5?;Br?6?] were studied,and then reacted with Mo?CO?₆ in THF as solvent for 8 h.Six mononuclear carbonyl molybdenum complexes were isolated[??²-2-C₅H₄N?CH=N?C₆H₅?]Mo?CO?₄?17??[??²-2-C₅H₄N?CH=N?C₆H₄-4-CH₃?]Mo?CO?₄?18??[??²-2-C₅H₄N?CH=N?C₆H₄-4-OMe?]Mo?CO?₄?19?? [??²-2-C₅H₄N?CH=N?C₆H₄-4-CF₃?]Mo?CO?₄?20?? [??²-2-C₅H₄N?CH=N?C₆H₄-4-Cl?]Mo?CO?₄?21??[??²-2-C₅H₄N?CH=N?C₆H₄-4-Br?]Mo?CO?₄?22?,the composition and structure of compounds were characterized by IR?1H NMR?13C NMR and elemental analysis.The crystal structure of 17,18,20 metals carbonyl ruthenium complex were determined by X-ray single crystal diffractometer.The single crystal structure shows that: the 17,18,20 compounds are mononuclear complexes.The two N atoms in the ligand are coordinated with one Mo atom at the same time,thus chelating to form a stable five-membered ring structure.Complexes 17,18 and 20 are triclinic,space groups are P?.?3?The complexes 17²2 catalytic Friedel-Crafts alkylation reaction of Catalyzed anisole and its derivatives with a variety of acylation reagents were studied,respectively.The results indicated that cyclohexanoyl chloride> cinnamoyl chloride> benzoyl chloride> benzoyl chloride for acylating agents;For the anisole and its derivatives,the general trend is roughly anisole> o-methyl anisole> o-bromoanisole> p-methylanisole> p-bromoanisole?individual May be o-methyl anisole> anisole?,consistent with electrophilic substitution reaction characteristics.With the same acylating reagent,anisole and o-methyl anisole were significantly higher than o-bromoanisole,p-methyl anisole and p-bromoanisole,and anisole,o-bromoanisole,o-methyl anisole and the acylation reagent reaction product ispara-substituted,while the reaction product of p-methyl anisole,p-bromoanisole and acylating agent is ortho-substituted.As with the conventional Lewis acid catalyzed Friedel-Crafts acylation reaction,no multicomponent-substituted product is produced.This indicates that the catalytic system has a high regional selectivity.