TY - JOUR
T1 - Complexes of Pd(II), 6 -C 6 H 6 Ru(II), and 5 -CpRh(III) with Chalcogenated Schiff Bases of Anthracene-9-carbaldehyde and Base-Free Catalytic Transfer Hydrogenation of Aldehydes/Ketones and N-Alkylation of Amines
AU - Dubey, Pooja
AU - Gupta, Sonu
AU - Singh, Ajai K.
N1 - Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/2/25
Y1 - 2019/2/25
N2 - The condensation of 2-(phenylsulfanyl)ethylamine and 2-(phenylselenyl)ethylamine with anthracene-9-carbaldehyde resulted in Schiff bases [PhS(CH 2 ) 2 C-N-9-C 14 H 9 ](L1) and [PhSe(CH 2 ) 2 C-N-9-C 14 H 9 ] (L2), respectively. Na 2 [PdCl 4 ] treatment of L1/L2 in acetone-water mixture for 3 h at room temperature gave palladacycle [PdCl(C - , N, S/Se)] (1/2; L1/L2-H = (C - , N, S)/(C - , N, Se)). The reaction of [( 6 -C 6 H 6 )RuCl(μ-Cl)] 2 with L1/L2 in methanol for 8 h at room temperature (followed by addition of NH 4 PF 6 ) afforded half-sandwich complex [( 6 -C 6 H 6 )Ru(L)Cl][PF 6 ], 3/4: (L = L1/L2 - (N, E) ligand). The reaction of [( 5 -Cp)RhCl(μ-Cl)] 2 with L1 /L2 in the presence of CH 3 COONa at 50 °C (followed by treatment with NH 4 PF 6 ) resulted in [( 5 -Cp)Rh(L-H)][PF 6 ], 5/6: (L = L1/L2). On carrying out the reaction of [( 5 -Cp)RhCl(μ-Cl)] 2 with these ligands at room temperature and in the absence of CH 3 COONa, complex [( 5 -Cp)Rh(L)Cl][PF 6 ], 7/8 (L = L1/L2 - (N, E) ligand), was formed. Complexes 1-8 were authenticated with 1 H, 13 C{ 1 H}, and 77 Se{ 1 H} NMR spectroscopy, high-resolution mass spectrometry, elemental analyses, and single-crystal X-ray diffraction. The moisture- And air-insensitive complexes of Pd(II) (1, 2), Ru(II) (3, 4) and Rh(III) (5-8) were thermally stable. Palladium and rhodium (under base-free condition) species efficiently catalyzed transfer hydrogenation (propan-2-ol as H-source). At room temperature conversion was 90% in TH catalyzed with 0.2 mol % of 2. N-Alkylation of aniline with benzyl alcohol under base-free condition was promoted by 3-8. The 7 was most efficient for the two base-free catalytic reactions. For TH optimum loading of 1-2 and 5-8 as catalyst is 0.05-0.2 and 0.2-0.5 mol % respectively. The optimum temperatures are 80 and 100 °C for TH and N-alkylation, respectively. The optimum loading of 3-8 for N-alkylation is 0.5 mol %. Mercury poisoning test supported homogeneous pathway for the two catalytic reactions. The rhodacycles probably gave real catalytic species by losing a Cp∗ group.
AB - The condensation of 2-(phenylsulfanyl)ethylamine and 2-(phenylselenyl)ethylamine with anthracene-9-carbaldehyde resulted in Schiff bases [PhS(CH 2 ) 2 C-N-9-C 14 H 9 ](L1) and [PhSe(CH 2 ) 2 C-N-9-C 14 H 9 ] (L2), respectively. Na 2 [PdCl 4 ] treatment of L1/L2 in acetone-water mixture for 3 h at room temperature gave palladacycle [PdCl(C - , N, S/Se)] (1/2; L1/L2-H = (C - , N, S)/(C - , N, Se)). The reaction of [( 6 -C 6 H 6 )RuCl(μ-Cl)] 2 with L1/L2 in methanol for 8 h at room temperature (followed by addition of NH 4 PF 6 ) afforded half-sandwich complex [( 6 -C 6 H 6 )Ru(L)Cl][PF 6 ], 3/4: (L = L1/L2 - (N, E) ligand). The reaction of [( 5 -Cp)RhCl(μ-Cl)] 2 with L1 /L2 in the presence of CH 3 COONa at 50 °C (followed by treatment with NH 4 PF 6 ) resulted in [( 5 -Cp)Rh(L-H)][PF 6 ], 5/6: (L = L1/L2). On carrying out the reaction of [( 5 -Cp)RhCl(μ-Cl)] 2 with these ligands at room temperature and in the absence of CH 3 COONa, complex [( 5 -Cp)Rh(L)Cl][PF 6 ], 7/8 (L = L1/L2 - (N, E) ligand), was formed. Complexes 1-8 were authenticated with 1 H, 13 C{ 1 H}, and 77 Se{ 1 H} NMR spectroscopy, high-resolution mass spectrometry, elemental analyses, and single-crystal X-ray diffraction. The moisture- And air-insensitive complexes of Pd(II) (1, 2), Ru(II) (3, 4) and Rh(III) (5-8) were thermally stable. Palladium and rhodium (under base-free condition) species efficiently catalyzed transfer hydrogenation (propan-2-ol as H-source). At room temperature conversion was 90% in TH catalyzed with 0.2 mol % of 2. N-Alkylation of aniline with benzyl alcohol under base-free condition was promoted by 3-8. The 7 was most efficient for the two base-free catalytic reactions. For TH optimum loading of 1-2 and 5-8 as catalyst is 0.05-0.2 and 0.2-0.5 mol % respectively. The optimum temperatures are 80 and 100 °C for TH and N-alkylation, respectively. The optimum loading of 3-8 for N-alkylation is 0.5 mol %. Mercury poisoning test supported homogeneous pathway for the two catalytic reactions. The rhodacycles probably gave real catalytic species by losing a Cp∗ group.
UR - http://www.scopus.com/inward/record.url?scp=85061915710&partnerID=8YFLogxK
U2 - 10.1021/acs.organomet.8b00908
DO - 10.1021/acs.organomet.8b00908
M3 - Article
AN - SCOPUS:85061915710
SN - 0276-7333
VL - 38
SP - 944
EP - 961
JO - Organometallics
JF - Organometallics
IS - 4
ER -
