Phosphorus guiding palladium: [4 + 4] metallomacrocyclic PdII complex and self-assembly of heterometallic PdII/ZnII grid-type complex

The reaction of heteroditopic ligand 1 featuring a hard pyridine-hydrazone-pyrimidine (N,N,N) site and a softer pyrimidine-hydrazone-phosphane (N,N,P) pocket with [Pd(CH3CN)4](OTf)2 in different metal-to-ligand ratios (M : L) gave the homobimetallic PdII complex [Pd2(1)(CH3CN)2](OTf)4 (2, M : L ratio 2 : 1), the [4 + 4] metallomacrocyclic PdII complex [Pd(1)]4(OTf)8 (3, M : L ratio 1 : 1) and the monometallic complex [Pd(1)2](OTf)2 (4, M : L ratio 1 : 2). The soft N,N,P pocket preferably coordinates PdII, while the harder N,N,N coordination site selectively binds ZnII forming the homoleptic meridional "corner" complexes [Zn(1)2](OTf)2 (5) and [Pd2Zn(1)2](OTf)6 (6). The distinctive coordination behavior of ligand 1 is highlighted by the self-assembly of the heterometallic PdII/ZnII grid-type complex [Pd2Zn2(1)2](OTf)8 (7) in a one-pot reaction. Complexes 2-7 were characterized by mass spectrometry, UV/Vis and NMR spectroscopy including DOSY NMR, and single-crystal X-ray diffraction studies were performed for 2-4 and 7.