Synthesis, Crystal Structures And Properties Of Coinage Metal Complexes Of Pyrazole Ligands

In this paper, we have synthesized five organic ligands and nineteen complexeswith the IB group metals(Cu(I), Ag(I), Au(I)). These ligands and complexes werecharacterized by IR spectra,1H NMR, CHN microanalyses, thermal analyses P-XRDet.al. The structures of these complexes were determined by X-ray diffraction.The five ligands and their abbreviation:3,5-diphenylpyrazole (Ph2pzH)4-chloro-3,5-diphenylpyrazole (ClPh2pzH)4-bromo-3,5-diphenylpyrazole (BrPh2pzH)4-iodo-3,5-diphenylpyrazole (IPh2pzH)4-(4-bromobenzyl)-3,5-diphenylpyrazole (HL)The nineteen complexes and their molecular formula:[Cu(ClPh2pz)]3（1,2,3）[Cu(BrPh2pz)]3（4）[CuL]3（5）[Cu(IPh2pz)]3（6）[Ag(ClPh2pz)]3·CH3CN （7）[Ag(ClPh2pz)]3·2CH2Cl2（8）[Ag(ClPh2pz)]3·PhCN （9）[Ag(ClPh2pz)]3·1/2CH2Br2（10）[Ag(IPh2pz)]3（11）[Au(ClPh2pz)]3·CH2Cl2（12）[Au(IPh2pz)]3（13）[{Cu(ClPh2pz)}(OMe)]6（14）[{Cu(BrPh2pz)}(OMe)]6（15）[{Cu(IPh2pz)}(OMe)]6（16）[{Cu(Ph2pz)}(OMe)]6（17）Cu5(ClPh2pz)6(OH)（18） Cu5(BrPh2pz)6(μ-OH)·CH3CN （19）The complexes are divided into three categories according to the styles ofcoordination:1. Trinuclear complexes:1-13are0-D trimer complexes. Complexes1,2and3are isomers which contain the same structural unit, but the space packing ways aredifferent; Complexes7,8,9and10have the same structural units, there are weakinteractions between [Ag(ClPh2pz)]3and solvent molecules CH3CN, CH2Cl2, PhCNand CH2Br2,which lead to the different space packing ways.2. Hexanuclear crown complexes:14-17are0-D six nuclear crown structurewhich include six ligands, six copper atoms and six methoxy groups.This is a resultof the trinuclear complexes Cu3pz3in methanol and oxidative atmosphere.3. Pentanuclear complexes:18,19are0-D five nuclear complexes, whichinclude six ligands, five copper atoms (three copper atoms are two coordinated andtwo copper atoms are four coordination) and a hydroxyl. This kind of structure is alsotransformed from trinuclear complexes Cu3pz3.Based on our work, we can draw some conclusions as follows:1. The trinuclear complexes M3N6are obtained from single pyrazole liginds,which are π acidity, and the trend: Ag> Cu> Au. The substituent (Cl, Br, I) iselectronic absorption, which can enhanc the π acidity of M3N6. Halogens can point tothe π acidic center of M3N6act as weak base.2. Some basic molecules with the M3N6of Ag, Au can formed a series oftrinuclear complexes, we can obtianed the basic trend, e.g. Ipz≥Brpz> Clpzfor coppertrimers；Ipz≥Brpz> CH3CN> Clpz≥Ph(PhCN)> Cl(CH2Cl2) for silver trimers andIpz> Brpz≥Clpzfor gold trimers.3. We obtained the MEP and frontier orbitals of some of the trinuclearpyrazolates by DFT method. According to the calculation results, we believe thenature of M3···X are ionic δ+···δ-attraction, covalent LUMO-HOMO overlap and π-πinteraction.4. The complexes of Cu3N6are unstable, and they can be transformed tohexanuclear crown complexes in methanol and oxidative atmosphere. Thepentanuclear complexes of mixed valence state of Cu(I)/Cu(II) were obtained in oxidative atmosphere.