Exploiting the versatility of pyridyl ligands for the preparation of diorganotin (IV) adducts: spectral, crystallographic and Hirshfeld surface analysis studies

Abstract

Diorganotin (IV) complexes SnR2X2 (R = Me, Ph; X = Cl, NCS) form a series of versatile complexes when react with bidentate substituted pyridyl ligands. The reaction of dimethyltin dichloride with 5,5′‐dimethyl‐2,2′‐bipyridine (5,5′‐Me2bpy) resulted in the formation of [SnMe2Cl2(5,5′‐Me2bpy)] (1). Moreover, the reaction of SnMe2(NSC)2 with 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine (bu2bpy), 1,10‐phenanthroline (phen) and 4,7‐diphenyl‐1,10‐phenanthroline (bphen) affords the hexa‐coordinated complexes [SnMe2(NCS)2(bu2bpy)] (2), [SnMe2(NCS)2(phen)] (3) and [SnMe2(NCS)2(bphen)] (4), respectively. The resulting complexes have been characterized using elemental analysis, IR, multinuclear NMR (1H, 13C, 119Sn) and DEPT‐135° NMR spectroscopy. On the other hand, the reaction of diphenyltin dichloride with 2,2′‐biquinoline (biq) and 4,7‐phenantroline (4,7‐phen) led to the formation of polymeric complexes of [SnPh2Cl2(4,7‐phen)]n (5) and [SnPh2Cl2(biq)]n (6). The NMR spectra, however, reveal the ligand lability in solution and suggest a coordination number of 5. The X‐ray crystal structures of complexes [SnMe2Cl2(5,5′‐Me2bpy)] (1), [SnMe2(NCS)2(bu2bpy)] (2) and [SnMe2(NCS)2(bphen)] (4) have been determined which reveal that the geometry around the tin atom is distorted octahedral with trans‐[SnMe2] configuration. Interestingly, the crystal structure of (H2biq)2[SnPh2Cl4]•2CHCl3 (7) was characterized by X‐ray crystallography from a chloroform solution of [SnPh2Cl2(biq)]n (6) indicating the formation of doubly protonated [H2biq]+ and [Ph2SnCl4]2− which are stabilized by a network of hydrogen bonds with a feature of trans‐[SnPh2]. The 3D Hirshfeld surface analysis and 2D fingerprint maps were used for quantitative mapping out of the intermolecular interactions for 1, 2, 4 and 7 which show the presence of π‐π and hydrogen bonding interactions which are associated between donor and acceptor atoms (N, S, Cl) in the solid state.