Hanan A. Qaseer

Oxidation of ketone by palladium(II). α-Hydroxyketone synthesis catalyzed by a bimetallic palladium(II) complex

Abstract A bimetallic palladium(II) complex containing a triketone ligand and a bridging dinitrogen ligand oxidizes ketones in aqueous THF to α-hydroxyketone by a direct air oxidation. While the normal synthesis of α-hydroxyketones involves a series of reactions, this synthesis performs the transformation in one step in a catalytic air oxidation. This synthesis does not involve an olefin and is almost unprecedented in transition metal catalysis. Its main virtue is its simplicity and actually it is an enolization reaction. Methanesulfonic acid is used to accelerate the enolization of ketones. The reaction is carried out in the presence of CuCl 2 and/or dioxygen only. In particular, it is found that the hydroxyketone formation does not require the presence of CuCl 2 . Matrix assisted laser desorption ionization (MALDI) and time-of-flight mass spectrometry (TOFMS) are used to record the mass spectra of α-hydroxyketones products. α-Cyano-4-hydroxycinnamic acid (CHCA) matrix promoted the molecular ion detection when 180 pmol of α-hydroxyketones is introduced into the TOFMS.

Complexes of 2-(2′-pyridyl)quinoline and 3,6-Di(4′-pyridyl)-S-tetrazine

Abstract The reactions of 2-(2′-pyridyl)quinoline (pq) with RhCl 3 · 3 H 2 O, K 3 RhBr 6 (prepared in situ ), [Rh(CO) 2 Cl] 2 and M(PhCN) 2 X 2 (M=Pd, Pt; X= Cl, Br, I) and 3,6-di(4′-pyridyl)-1,2,4,5-S-tetrazine (s-dpt) with [Ru(bpy) 2 ClNO](PF 6 ) 2 have been investigated. The new complexes cis -[Rh(pq) 2 Cl 2 ]- (PF 6 ), cis -[Rh(pq) 2 Br 2 ]Br, cis -[Rh(pq) 2 Cl 2 ] [Rh- (CO) 2 Cl 2 ]·H 2 O, cis -Pd(pq)X 2 (X=Cl, Br), cis - Pt(pq)X 2 (X=Cl, Br, I) and [{(bpy) 2 ClRu} 2 -dpt]- (PF 6 ) 2 ·3H 2 O have been characterized by elemental analyses, conductivity and cyclic voltammetric measurements, infrared, electronic absorption and 1 H NMR data.

Complexes of palladium, platinum and rhodium with 2,2′-biquinoline and 2-(2′-pyridyl)quinoline

SummaryThe reactions of 2,2′-biquinoline(biq) with M(PhCN)2X2 (M=Pd; X=Cl or Br; M=Pt, X=Cl, Br or I), K2PtCl4 and RhCl3·3H2O and of 2-(2′-pyridyl)quinoline (pq) with K2PtCl4 and RhCl3·3H2O have been investigated. The isolated complexescis-[Pd(biq)X2] (X=Cl or Br),cis-[Pt(biq)Cl2],cis-[Pt(biq)Cl2]·H2O,trans-[Pt(biq)2Br2]·5H2O, [Pt3(biq)2I6],mer-[Rh(biq)Cl3-(H2O)] andmer-[Rh(pq)Cl3(H2O)] have been characterized by elemental analyses, conductivity measurements, i.r., electronic, and1H n.m.r. spectra. The reaction of pq with K2PtCl4 in 1M H2SO4 gave the salt 2-(2′-pyridyl) quinolinium tetrachloroplatinate(II) pentahydrate, (pqH)2[PtCl4]·5H2O; when the reaction was carried out in aqueous acetone,cis-[Pt(pq)Cl2] was obtained. A new method for the synthesis ofcis-[Rh(biq)2X2]X (X=Cl or Br) is described; both compounds have been further characterized by1H n.m.r.

Substituted dipyridylpyridazine rhodium(III) complexes

Abstract3,6-Bis(2′-pyridyl)pyridazine derivatives (n-dppn) react with hydrated rhodium(III) chloride and bromide (prepared in situ) to give cis-[Rh(n-dppn)2Cl2]PF6·xH2O (n = 5, 6, 7, 8) and cis-[Rh(n-dppn)2Br2]Br·xH2O (n = 5, 7) complexes, which have been characterized by elemental analyses, conductivity measurements, i.r., electronic and 1H- and 13C-n.m.r. spectra.

Complexes of substituted dipyridylpyridazines with palladium(II) and platinum(II)

Reactions of 3,6-bis(2′-pyridyl)pyridazine derivatives (n-dppn)¶ with MX2(PhCN)2 (M = Pd, Pt; X = Cl, Br) have been investigated. The new complexes cis-[PdCl2(n-dppn)] (n = 5, 6, 8, 12), cis-[PtCl2(n-dppn)] · H2O (n = 5, 6), cis-[PtCl2(8-dppn)] and cis-[PtBr2(5-dppn)] have been characterized by elemental analyses, conductivity measurements, infrared, electronic and 1H-NMR spectra. ¶For the n-dppn ligands, n stands for the size of the cyclic aliphatic ring on positions 4 and 5 of the pyridazine ring, n = 5, 6, 8, and 12.