The unsymmetric bis-imidazolium salts ligands 4a and b were prepared by stepwise reactions of 2,6-bis(bromomethylene)-4-(t-butyl)anisole (1) with two different N-substituted imidazoles. Reaction of the bis-imidazolium ligands with Ag2O in acetonitrile gave the dinuclear bis(N-heterocyclic carbene) complexes 5a and b. The molecular structure of complex 5a was determined by single-crystal X-ray diffraction analysis. In complex 5a and b, the two Ccarbene–Ag–Ccarbene axes are in a crossed conformation, two O atoms from phenoxyl groups weakly coordinate to different Ag ions and the two p-t-butylphenoxyl groups adopted a staggered conformation. To regulate the molecular shape of the N-heterocyclic carbene Ag(I) macrocyclic complexes, two tetradentate imidazolium ligands (9a and b) were prepared. The bimetallic NHC–Ag(I) complexes 10a and b were obtained by the reaction of 9a and b and Ag2O in acetonitrile. Constrained by the chain (the dioxoethylene or dioxomethylenebenzene chain in 10a or 10b, respectively) at the O-position of the phenoxyl group, the two p-methylphenoxyl groups in complexes 10a and b might be predicted to have a cone conformation. The ligands and the corresponding NHC metal complexes have been characterized by elemental analysis, 1H NMR and 13C NMR, HRMS spectra, as well as TGA and DTA spectra being determined for complexes 10a and b. The TGA curves show that these NHC–Ag complexes have good thermal stability.Two unsymmetrical bis-imidazolium ligands, two symmetric tetra-imidazolium ligands and their dinuclear NHC–Ag macrocyclic complexes have been prepared and characterized. The X-ray diffraction analysis showed that the molecule 5a adopts a twisted macrocyclic structure, in which the two Ccarbene–Ag–Ccarbene axials are crossed and the two p-t-butylphenoxyl groups are in a staggered conformation.

A novel long chain diphosphine ligand with a pyridine-diamino bridge, 2,6-bis(N-benzyl-N-diphenylphosphinomethylamino)pyridine (PNP1), was prepared conveniently using the Mannich reaction of HPPh2 with paraformaldehyde and 2,6-bis(N-benzylamino)pyridine in high yield. Reactions of the ligand with metal complexes, M(COD)Cl2 (M = Pd, Pt), M(CH3CN)4ClO4 (M = Cu, Ag) and M(CO)6 (M = Mo, W) afforded the corresponding 10-numbered monometallic macrocyclic complexes with an uncoordinated pyridyl bridge. The monometallic chelate PdCl2(PNP1) continued to react with Ag+ or Cu+ giving the μ-Cl bridged bicyclic metallic complex (μ-Cl)2[PdCl(PNP1)]2. The diphenylphosphine group coordinated with metal ion in cis-form in all the 10-numbered macrocyclic metal complexes. Ligand PNP1 and another known analogous 2,6-bis(N-diphenylphosphinoamino)pyridine (PNP2) reacted with Au(SMe2)Cl giving the corresponding bimetallic Au2Cl2(PNP1) and Au2Cl2(PNP2), respectively. The latter bimetallic complexes continued to react with Ag+ and diphosphine ligand to give the corresponding bimetallic macrocyclic complexes Au2(ligand)2(ClO4)2. All the complexes were characterized and the structures of some complexes were confirmed by X-ray single crystallography determination.A long chain diphosphine ligand with a pyridine-diamino bridge, 2,6-bis(N-benzyl-N-diphenylphosphinomethylamino)pyridine (PNP1), was prepared and was used to react with metal complexes, M(COD)Cl2 (M = Pd, Pt), M(CH3CN)4ClO4 (M = Cu, Ag) and M(CO)6 (M = Mo, W) to afford the corresponding 10-numbered monometallic macrocyclic complexes with an uncoordinated pyridyl bridge.

Reaction of a new large-bite P,N-ligand, 2-(N-diphenylphosphinomethyl-N-benzyl)aminopyridine (1) with (COD)PtCl2 and (COD)Pt(CCPh)2 give cis-(L)2PtCl2 (2) and trans-(L)2Pt(CCPh)2 (3), respectively. Complex 3 reacted with M(I) (M = Cu, Ag) perchlorate using its pyridyl and alkynyl groups to afford a novel type of mixed-metal macrocyclic complexes PtM2(L)2(CCPh)2(ClO4)2 (M = Cu, 4; M = Ag, 5). Complex 4 can be converted to the solvated complexes Pt[Cu(solvent)]2(μ-L)2(CCPh)2(ClO4)2 (solvent = H2O, 4; CH3CN, 4″) by recrystallization of 4 in the corresponding solvents. The crystal structures of complexes 2, 3, 4 and 4″·CH2Cl2 and luminescence properties of 3, 4 and 5 have been determined.