New Pb(II)‐Ammine complexes as intermediates from the interaction of CH 3 NH 2 with PbX 2 and CH 3 NH 3 PbX 3 (X=Cl, Br)

In continuation of our investigations of the “molten salt approach” for MAPbI 3 , we now report on the interaction of gaseous CH 3 NH 2 with Pb X 2 ( X =Cl, Br) and MAPb X 3 ( X =Cl, Br). We have characterized cubic [Pb(CH 3 NH 2 ) 6 ]Br 2 with a close similarity to the K 2 PtCl 6 type and partially disordered octahedra [Pb(CH 3 NH 2 ) 6 ] 2+ . Release of CH 3 NH 2 yields Pb(CH 3 NH 2 ) 3 Br 2 . Here Pb 2+ is octahedrally coordinated by 3 CH 3 NH 2 ligands and 3 Br − as a fac ‐isomer. Charge neutrality is achieved by one terminal and two bridging Br − forming edge‐sharing dimers. For the chloride there is only a partial exchange of the halide ligands. Pb(CH 3 NH 2 ) 2 Cl 2 , with a novel cubic structure, shows two different octahedra: PbCl 6 and Pb(CH 3 NH 2 ) 3 Cl 3 . Pb(CH 3 NH 2 ) 3 Cl 2 is closely related to Pb(CH 3 NH 2 ) 3 Br 2 , i. e. Pb(CH 3 NH 2 ) 3 Cl 3 octahedra in fac ‐geometry with one terminal and two bridging Cl − , but herez the polyhedra form a linear chain. In all representatives with mixed ligands the interaction with X − is significantly weaker than with CH 3 NH 2 . H‐bridges N−H⋅⋅⋅X contribute to the interaction between the Pb(CH 3 NH 2 ) 3 X 3 units. All compounds decompose in air to Pb(OH) X and MAPb X 3 ( X =Cl, Br).