The different coordination behavior of the flexible yet sterically demanding, hemilabile P,N ligand bis(quinoline‐2‐ylmethyl)phenylphosphine ( bqmpp ) towards selected Cu I , Ag I and Au I species is described. The resulting X‐ray crystal structures reveal interesting coordination geometries. With [Cu(MeCN) 4 ]BF 4 , compound 1 [Cu 2 (bqmpp) 2 ](BF 4 ) 2 is obtained, wherein the copper(I) atoms display a distorted square planar and square pyramidal geometry. The steric demand and π‐stacking of the ligand allow for a short Cu⋅⋅⋅Cu distance (2.588(9) Å). Cu I complex 2 [Cu 4 Cl 3 (bqmpp) 2 ]BF 4 contains a rarely observed Cu 4 Cl 3 cluster, probably enabled by dichloromethane as the chloride source. In the cluster, even shorter Cu⋅⋅⋅Cu distances (2.447(1) Å) are present. The reaction of Ag[SbF 6 ] with the ligand leads to a dinuclear compound ( 3 ) in solution as confirmed by 31 P{ 1 H} NMR spectroscopy. During crystallization, instead of the expected phosphine complex 3 , a tris(quinoline‐2‐ylmethyl)bisphenyl‐phosphine ( tqmbp ) compound [Ag 2 (tqmbp) 2 ](SbF 6 ) 2 4 is formed by elimination of quinaldine. The Au(I) compound [Au 2 (bqmpp) 2 ]PF 6 ( 5 ) is prepared as expected and shows a linear arrangement of two phosphine ligands around Au I .

Aryl- and heteroaryl-dichlorophosphines are mildly and selectively made in a one-pot synthesis in moderate to good yields starting from the respective aryl bromides or five-membered heterocycles, following lithiation with nBuLi, transmetalation with ZnCl2, and subsequently the reaction with PCl3. Selected aryl- and heteroaryl-dichlorophosphines were successfully synthesized using this reaction method and could easily be purified after isolation. The intermediate formation of the organozinc species is essential, as it prevents the formation of multiple substitution products. Important are also the reaction conditions: the usage of the proper solvent for the respective aromatic precursors and removal of the remaining salts by addition of a dioxane/pentane mixture. Depending on the solvent and steric demand of the substituent, mono- and bis-substitution products can be formed but formation also prevented. Hereby, different organozinc species might play an important role.

Easily accessible blue-emitting materials are in the focus of ongoing research, as they still lack the efficiency and lifetime of their red and green counterparts. The new multidentate phosphine oxide ligands and two respective ZnCl 2 complexes presented here combine a straightforward synthesis with high yields and show interesting luminescent properties. The free ligand exhibits blue luminescence in the crystalline state, but not in amorphous films or diluted solution. In contrast, the Zn(II) complexes shows intense blue luminescence in the crystalline state as well as in amorphous thin films and in solution. Fluorescence lifetime imaging microscopy measurements show luminescence lifetimes of 3-6 ns indicative of fluorescence. By combining the experimental data with quantum chemical calculations, we propose a model where the conformation of the molecule is restricted, either via the crystal environment, aggregation, or the steric fixation by the coordinating central atom, blocking the nonradiative relaxation from the excited into the ground electronic state. However, this nonradiative relaxation is still possible in the gas phase via elongation of a PC bond. These results may provide a general mechanism to explain the luminescence properties in a whole class of organic phosphine oxides.