Synthesis And Catalytic Activity Of Nickel(Ⅱ) Thiolate Complexes

In the presence of N-or P-donor ligand, reactions of [Zn(Tab)4](PF6)2(Tab=4-(trimethylammonio)benzenethiolate) with Ni(II) salts resulted in the formation of sixNi/Tab coordination complexes. Some of these complexes displayed high catalyticactivity toward the cross-coupling reactions of arylboronic acids and amines to formN-arylated amines. The main content of this thesis is described as follows:1) Reactions of [Zn(Tab)4](PF6)2with NiCl2·6H2O in the presence of2,2′-bipyridine (2,2′-bipy),1,10-phenanthroline (phen) or4,4′-dimethyl-2,2′-bipyridine(dmbipy) produced three complexes, namely[Ni3(Tab)4(2,2′-bipy)4]2Cl0.5(PF6)5.5·2.5MeCN (1·2.5MeCN),[Ni3(Tab)4(phen)4]2Cl0.5(PF6)5.5·2.5MeCN (2·2.5MeCN),[Ni3(Tab)4(dmbipy)4]2Cl0.5(PF6)5.5·2.5MeCN (3·2.5MeCN). Further reaction of[Zn(Tab)4](PF6)2with preformed mixture of nickel salt (NiCl2·6H2O or Ni(ClO4)2·6H2O)and diphosphine ligands (2-bis(diphenylphosphino)ethane (dppe) or1,4-bis(diphenylphosphino)butane (dppb)) resulted in the formation of a dinuclearcationic complex [Ni2(dppb)(μ-Tab)2(Tab)2](PF6)2(ClO4)2·2(CH2Cl2)0.5(4·2(CH2Cl2)0.5),and a mononuclear cationic complex [Ni(Tab)2(dppe)](PF6)2·CH2Cl2·0.5MeOH(5·CH2Cl2·0.5MeOH). Finally, reaction of NiCl2·6H2O with Tab followed by addition of2,2′-bipy resulted in the formation of [Tab-Tab][Ni(2,2′-bipy)3](PF6)4(6). Compounds13are structural analogs, with the central Ni(II) atoms in their hexacations connectedto two―Ni(2,2′-bipy)2‖units through two Tab ligand pairs, yielding a trinuclearstructure. Complex4has a dimeric structure in which the two Ni(II) atoms are linked bya pair of Tab ions and dppb ligand. The Ni(II) atom in5is coordinated by two S atomsfrom Tab ligands and two P atoms from one dppe ligand. In6, Tab is oxidized into[Tab-Tab]2+while the Ni(II) atom is coordinated by six N atoms from three2,2′-bipyligands. 2) Complexes1,4, and5displayed high catalytic activity toward cross-couplingreactions of arylboronic acids and amines to produce N-arylated amines. The optimalreaction conditions were identified as follows: catalyst loading ([Ni]=20mol%),2equiv. of DUB (as the base), and MeCN (as a solvent) with a reaction temperature of60°C. Under the optimized reaction conditions,13displayed high catalytic activity toproduce N-arylated amines with isolated yield up to70%.