The molecular Sn(IV) complexes, [SnCl₄{ⁿBuS(CH₂)₃SⁿBu}] (2), [SnCl₄(ⁿBu₂S)₂] (3) and [SnCl₄(ⁿBu₂Se)₂] (4) have been prepared in good yield from reaction of SnCl₄ with the appropriate chalcogenoether ligand in anhydrous hexane and, together with the known [SnCl₄{ⁿBuSe(CH₂)₃SeⁿBu}] (1), employed as single source precursors for the low pressure chemical vapour deposition of the corresponding tin dichalcogenide thin films. At elevated temperatures the bidentate ligand precursors, (1) and (2), also form the tin monochalcogenides, SnSe and SnS, respectively. In contrast, (3) gave a mixture of phases, SnS₂, Sn₂S₃ and SnS and (4) gave SnSe₂ only. The morphologies, elemental compositions and crystal structures of the resulting films have been determined by scanning electron microscopy, energy dispersive X-ray spectroscopy, grazing incidence X-ray diffraction and Raman spectroscopy. Van der Pauw measurements on the SnS₂, SnS and SnSe₂ films confirm their resistivities to be 2.9(9), 266(3) and 4.4(3) Ω cm, respectively.

Reaction of SnF₂ in MeOH with the appropriate neutral N- or O-donor ligands produces [SnF(2,2′-bipy)]₂SnF₆, [SnF(1,10-phen)]₂SnF₄ and [SnF₂(L)] L = Me₃PO, dmso or pyNO). The X-ray structures of [SnF(2,2′-bipy)]₂SnF₆, [SnF(1,10-phen)]₂SnF₄ and [SnF₂(dmso)], reveal trigonal pyramidal Sn(II) cores with longer fluorine bridges completing distorted 5- or 6-coordination. Attempts to prepare SnF₂ adducts with various phosphine or diphosphine ligands in MeCN failed, whilst in CH₂Cl₂ solution complex reactions involving the solvent occurred. The NHC, 1,3-(2,6-di-isopropylphenyl)imidazol-2-ylidene (IDiPP) and SnF₂ produced the imidazolium salt, [IDiPPH]SnF₃, the crystal structure of which revealed the first example of a discrete trifluorostannate(II) ion. In contrast, diphosphine complexes of tin(II) chloride formed readily, including [SnCl₂{Me₂P(CH₂)₂PMe₂}], [SnCl₂{o-C₆H₄(PMe₂)₂}], [SnCl₂{o-C₆H₄(PPh₂)₂}] and [(SnCl₂)₂(μ-Ph₂P(CH₂)₂PPh₂)], which were characterised by X-ray crystallography. The structures of [SnCl₂{Me₂P(CH₂)₂PMe₂}] and [SnCl₂{o-C₆H₄(PMe₂)₂}] reveal chloride-bridged dimers, but [SnCl₂{o-C₆H₄(PPh₂)₂}], although also dimeric, has very asymmetric diphosphine coordination best described as κ¹. The structures of [(SnCl₂)₂(μ-Ph₂P(CH₂)₂PPh₂)] and of [SnCl{o-C₆H₄(AsMe₂)₂}]SnCl₃ reveal trigonal pyramidal cores, but with longer Sn⋯Cl bridges affording polymeric structures. The synthesis of [SnCl₂(R₃EO)₂] (R = Ph, E = P or As; and R = Me, E = P) are also reported, along with the structure of [SnCl₂(Me₃PO)₂], which contains distorted tetragonal pyramidal Sn(II) coordination. X-ray structures are also reported for [(PMe₃)₂CH₂][SnCl₃]₂ and [Ph₂P(H)(CH₂)₂P(H)Ph₂][SnCl₃]₂, obtained as by-products from the attempts to synthesise phosphine complexes, as well as [(o-C₆H₄(PMe₂)₂CH₂]I₂. All complexes were characterised by microanalysis, IR and multinuclear NMR spectroscopy (¹H, ¹⁹F{¹H}, ³¹P{¹H } and, where solubility allowed, ¹¹⁹Sn). Comparisons are drawn with corresponding Sn(IV) and Ge(II) complexes.

Six-coordinate pseudo-octahedral complexes trans-[AlX₂(L–L)₂][AlX₄] (X = Cl, Br or I; L–L = o-C₆H₄(PMe₂)₂, Me₂P(CH₂)₂PMe₂) are produced from reaction of AlX₃ with the diphosphine in CH₂Cl₂ (X = Cl) or toluene (X = Br or I) solution. Four-coordinate dimers [Cl₃Al(μ-L′–L′)AlCl₃] (L′–L′ = Me₂P(CH₂)₂PMe₂, Cy₂P(CH₂)₂PCy₂), and the tetrahedral cation [AlCl₂{o-C₆H₄(PPh₂)₂}][AlCl₄] were also obtained. Both four- and five-coordinate complexes [AlX₃(PMe₃)] and [AlX₃(PMe₃)₂] could be isolated with PMe₃ depending upon the ratio of reagents used. These extremely moisture sensitive complexes have been characterised by microanalysis, IR and multinuclear NMR (¹H, ³¹P{¹H} and ²⁷Al) spectroscopy. X-ray crystal structures are reported for [AlCl₂{o-C₆H₄(PMe₂)₂}₂][AlCl₄], [AlCl₂{Me₂P(CH₂)₂PMe₂}₂][AlCl₄], [Cl₃Al{μ-Me₂P(CH₂)₂PMe₂}AlCl₃], [Cl₃Al{μ-Cy₂P(CH₂)₂PCy₂}AlCl₃], [AlCl₃(PMe₃)], [AlCl₃(PMe₃)₂], and for the six-coordinate cation complex [AlCl₂{o-C₆H₄(PPh₂)₂}₂][AlCl₄], although a bulk sample of the last could not be isolated. Tertiary arsines (AsPh₃ or AsEt₃) form only 1 : 1 complexes even with excess arsine present. The unstable [AlCl₂{o-C₆H₄(AsMe₂)₂}][AlCl₄] is also described, and shown to decompose rapidly in CH₂Cl₂ solution to form the diquaternised diarsine cation [o-C₆H₄(AsMe₂)₂(CH₂)][AlCl₄]₂, which was fully characterised. Comparisons are drawn with the corresponding gallium(III) systems (Cheng et al., Inorg. Chem., 2007, 46, 7215–7223) and with AlX₃ complexes of Group 16 ligands (George et al., Dalton Trans., 2014, 43, 3637–3648), and it is concluded that the differences between the Al and Ga systems reflect the higher Lewis acidity of aluminium(III) towards soft donor ligands.

The first phosphane complexes of germanium(IV) fluoride, trans-[GeF₄(PR₃)₂] (R = Me or Ph) and cis-[GeF₄(diphosphane)] (diphosphane = R₂P(CH₂)₂PR₂, R = Me, Et, Ph or Cy; o-C₆H₄(PR₂)₂, R = Me or Ph) have been prepared from [GeF₄(MeCN)₂] and the ligands in dry CH₂Cl₂ and characterised by microanalysis, IR, Raman, ¹H, ¹⁹F{¹H} and ³¹P{¹H} NMR spectroscopy. The crystal structures of [GeF₄(diphosphane)] (diphosphane = Ph₂P(CH₂)₂PPh₂ and o-C₆H₄(PMe₂)₂) have been determined and show the expected cis octahedral geometries. In anhydrous CH₂Cl₂ solution the complexes are slowly converted into the corresponding phosphane oxide adducts by dry O₂. The apparently contradictory literature on the reaction of GeCl₄ with phosphanes is clarified. The complexes trans-[GeCl₄(AsR₃)₂] (R = Me or Et) are obtained from GeCl₄ and AsR₃ either without solvent or in CH₂Cl₂, and the structures of trans-[GeCl₄(AsEt₃)₂] and Et₃AsCl₂ determined. Unexpectedly, the complexes of GeF₄ with arsane ligands are very unstable and have not been isolated in a pure state. The behaviour of the germanium(IV) halides towards phosphane and arsane ligands are compared with the corresponding silicon(IV) and tin(IV) systems.