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Tri2-thienylphosphine 1 has been transformed into chlorotri2-thienylphosphonium chloride 3 in the reaction with hexachloroethane, into tetra2-thienylphosphonium bromide 4 in a NiBr2-catalyzed quaternization with 2-bromothiophene, and into the p-tolylsulfonyliminotri2-thienylphosphorane 6 using “chloramine T”. Attempts to generate the homoleptic penta2-thienylphosphorane 2-C4H3S5P 5 by treating 3, 4, 6or the known PhO3PNSO2C6H4-2-Me 9 with 2-thienyllithium were unsuccessful. Tri2-furylphosphine 2 was converted into the related imine 7, but the reaction of 7or of 9with 2-furyllithium failed to give 2-C4H3O5P 8. It was only with the strained phosphorane PhC12H8PNSO2C6H4-4-Me C12H8 2,2′-biphenylylene 10 that with 2-C4H3OLi the corresponding phosphorane PhC12H8PC4H3O-2211 could be obtained 31P NMR: δ−106.7 ppm. In the arsenic series, tri2-thienyl- and tri2-furylarsine 12, 13 were converted into the tosylimino compounds 14, 15 and successfully transformed into the homoleptic arsoranes with 2-C4H3E–Li: penta2-thienyl- 16 and penta2-furyl-arsorane 17 are stable colourless crystalline solids, the NMR spectra of which indicate rapid pseudo-rotation in solution. The single crystal structure analysis of 17shows an only slightly distorted trigonal-bipyramidal configuration. In crystals of the phosphine 2and the arsine 13the molecules have a propeller configuration with approximate C3vsymmetry for the former, but Cssymmetry for the latter. The crystal structures of the precursors or intermediates 3, 4, 6, 9and 10have also been determined.

Convenient high-yield syntheses of the primary and di-primary heteroaryl-phosphines R–PH2 and H2P–R′–PH2 (with R = 2-thienyl, 2-furyl, and R′ = 2,5-thiophenediyl, 2,5-furandiyl, respectively) are presented. The products and a set of precursor molecules have been characterized by analytical and spectral data, and the crystal structures of selected molecules have been determined: 2-C4H3O–PCl2, 2,5-(Cl2P)2C4H2O, 2,5-[(Et2N)2P]2C4H2E (with E = O, S). In the crystals, the two molecules with –PCl2 substituents adopt trans conformations, while the other two have the –P(NEt2)2 groups rotated into a twist conformation. The reaction of the thienyl compounds with tris[(tert-phosphine)gold]oxonium tetrafluoroborates gave almost quantitative yields of the tri- and hexanuclear gold complexes, respectively: {2-C4H3S–P[Au(PR3)]3}+BF4− and [2,5-{[(R3P)Au]3P}2C4H2S]2+(BF4−)2, (R = tBu, Ph). The structures of the compounds with R3P = tBu3P ligands have been determined. In both cases the [2-C4H3/2S–P] units cap triangles of gold atoms in an array that can be described as three [Au(PR3)]+ cations bridged by a phosphido dianion (RP)2−.

The weak base pyridine has been found to deprotonate trichlorogermane HGeCl3with quantitative formation of pyridinium trichlorogermanateii, Py-HGeCl3−, the pyramidal structure of the anion resembling that of the isoelectronic AsCl3molecule. This course of the reaction supports the assignment of an inverse polarization −Ge–H of the bond in HGeCl3as compared to the Si–H− bond in trichlorosilane HSiCl3, which is known to form a 1 2 adduct with pyridine instead. Germanium tetrachloride also undergoes simple addition reactions with pyridine leading ultimately e.g. to GeCl4L2with L 4-ethyl-pyridine. Dichlorogallane gives 1 1 addition compounds HGaCl2L with L pyridine, 4-dimethylamino-pyridine, 4-cyano-pyridine, and 3,5-dimethyl-pyridine, the molecular structures of which have been determined by single crystal X-ray diffraction. Simple tetrahedral arrays of substituents around the gallium center with only minor distortions, and characteristic Ga–H stretching vibrations in the IR spectra, show that the Ga–H bond is untouched in the addition reactions. The addition of two equivalents of 3,5-dimethyl-pyridine to HGaCl2affords the 1 2 complex which was shown to have a trigonal-bipyramidal geometry with the hydride ligand in an equatorial position. In order to provide benchmark data, the 1 1 adducts GaCl3L and GaH3L with L 3,5-dimethyl-pyridine were also prepared and structurally characterized. Pyridinium tetrachlorogallateiii takes up pyridine, but the extra ligand is attached to the cation viahydrogen bonding leaving the anion unchanged: Py-HPyGaCl4−.