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Synthesis, Characterization and Theoretical Investigation on Thiazoline‐Derived Palladium‐Complexes‐Catalyzed Denitrogenative Cross‐Coupling of Aryl Halides with Arylhydrazines
Author(s) -
Sudharsan Murugesan,
Thirumoorthy Krishnan,
Nethaji Munirathinam,
Suresh Devarajan
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201902137
Subject(s) - palladium , homoleptic , chemistry , aryl , thiazoline , catalysis , ligand (biochemistry) , medicinal chemistry , crystal structure , coupling reaction , stereochemistry , crystallography , organic chemistry , metal , alkyl , biochemistry , receptor
Homo‐ and heteroleptic palladium(II) complexes of thiazoline derived ligand were synthesized and their catalytic application was reported. The reactions of [1‐(C 3 H 4 NS)‐2‐OH‐C 6 H 4 ] ( 2 ) with PdCl 2 and [(1‐(CH 3 ) 2 NCH 2 C 6 H 4 )PdCl] 2 in 2:1 molar ratios afforded the homoleptic palladium complex, [Pd{κ 1 2 , κ 1 2 ‐ N ,O‐(1‐(C 3 H 4 NS)‐2‐O‐C 6 H 4 ) 2 }] ( 3 ) and the heteroleptic palladium complex [{κ 1 2 ‐ N ,O‐(1‐(C 3 H 4 NS)‐2‐O‐C 6 H 4 )}Pd{(κ 2 2 ‐ N ,C‐(1‐(CH 3 ) 2 NCH 2 C 6 H 4 )}] ( 4 ) respectively. Equimolar reactions of 2 with PdCl 2 and 8‐quinolinol or 2‐methyl‐8‐quinolinol under reflux condition produced the heteroleptic palladium complexes [{κ 1 2 ‐ N ,O‐(1‐(C 3 H 4 NS)‐2‐O‐C 6 H 4 )}Pd{(κ 2 2 ‐ N ,O‐(8‐O‐C 9 H 6 ‐1‐N)}] ( 5 ) or [{κ 1 2 ‐ N ,O‐(1‐(C 3 H 4 NS)‐2‐O‐C 6 H 4 )}Pd{(κ 2 2 ‐ N ,O‐(8‐O‐2‐CH 3 ‐C 9 H 5 ‐1‐N)}] ( 6 ) in good yields. The molecular structures of ligand 2 and palladium complexes 3–6 were confirmed through multinuclear NMR spectroscopic techniques and further the crystal structure for palladium complexes 3 and 4 were established. Under the optimized reaction condition, the heteroleptic palladium complex 4 display an excellent catalytic activity with a maximum turn over frequency of 49.5 h −1 for the conversion of bi‐aryls from aryl halides and unactivated phenylhydrazine. The energies, activation barriers and transition state structures of reaction involved in the catalytic cycle were assessed by utilizing quantum chemical method to confirm C sp 2 ‐C sp 2 bond formation reaction catalyzed by heteroleptic palladium complex 4 .