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Syntheses and room-temperature single-crystal X-ray determinations are recorded for a number of adducts of BiX3/N,N′-bidentate 1 : 2 stoichiometry (N,N′-bidentate = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen)). BiX3/bpy (1 : 2), X = Br, I, are isomorphous, monoclinic, P21/c, a≈ 7·5, b≈ 31, c≈ 10·3 Å, β ≈ 113°, Z= 4; conventional Ron |F| were 0·058, 0·055 for No1744, 2068 independent ‘observed’ (I> 3σ(I)) reflections. BiCl3/phen (1 : 2) is monoclinic, P21/C, a9·675(3), b31·845(7), c7·756(2) Å, β 109·94(2), Z= 4, R0·071 for No2537, while BiBr3/phen (1 : 2), also monoclinic, P21/c, has a17·590(5), b8·812(2), c17·537(7) Å, β 117·58(3)°, Z= 4; R0·083 for No890. BiX3/phen (1 : 2).S, X/S= Br/MeCN, I/CH2Cl2, are isomorphous, orthorhombic, Pna21, a≈ 20·7, b≈ 14·2, c≈ 8·9 Å, Z= 4, R0·060, 0·046 for No1553, 2423 respectively. All complexes are mononuclear with seven-coordinate (N2)2BiX3bismuth environments. Bands in the far-infrared spectra due to the v(BiX) vibrations in [(phen)2BiCl3] and [(bpy)2BiX3] (X = Br, I) are assigned and discussed in relation to the structures of the complexes.

Syntheses and room-temperature single-crystal X-ray structural characterization of binuclear 1 : 2 adducts formed between silver(I) halides, AgX (X = Cl, Br, I), and triphenylstibine, SbPh3, are described. The three complexes are isomorphous, being triclinic, P-1, a≈ 18·5, b≈ 14·6, c≈ 14·5 Å, α ≈ 62·5, β ≈ 74, γ ≈ 77°, Z= 2 centrosymmetric dimers. Conventional Ron Fwere 0·043, 0·038 and 0·046 for 4984, 8479 and 4166 independent, ‘observed’ (I > 3σ(I)) reflections respectively. In [(Ph3b)2Ag(µ-X)2Ag(SbPh3)2], Ag–Sb range between 2·702(1) and 2·744(2) Å, lengthening slightly from chloride to iodide; Ag–X are 2·567(5)–2·628(4) (Cl), 2·684(1)–2·737(1) (Br) and 2·826(3)–2·869(3) Å (I). The far-infrared spectra of [(Ph3Sb)2Ag(µ-X)2Ag(SbPh3)2] show v(AgX) bands at 178, 158 (X = Cl), 121 (X = Br) and 110 cm-1(X = I). The splittings and band widths reflect a decrease in the degree of distortion of the Ag(µ-X)2Ag units from a symmetrically bridged structure from X = Cl to I.

Syntheses and room-temperature single-crystal X-ray structural characterization of a number of 1 : 1 ‘cube tetramer’ adducts of copper(I) and silver(I) halides, MX, with triphenylarsine, AsPh3, are recorded, being [XM(AsPh3)]4. The CuBr adduct, obtained unsolvated from toluene, orthorhombic Pbcn, a17·844(5), b20·778(8), c18·430(4) Å, Z= 4 tetramers, conventional Ron |F| 0·058 for No1309 independent ‘observed’ reflctions (I > 3σ(I)), is isomorphous with previously recorded [ClAg(PPh3)]4, the tetramer having crystallographically imposed 2symmetry. The CuI adduct, previously recorded as a monobenzene solvate, has been isolated unsolvated from toluene, monoclinic, P21/n, a19·70(5), b27·110(7), c13·59(2) Å, β 98·84(9)°, Z= 4 tetramers, R0·087 for No4359, isomorphous with previously recorded [ICu(PPh3)]4, as a 6? benzene solvate, triclinic, P-1 a26·688(2), b15·180(7), c13·090(1) Å, α 85·41(2), β 87·580(7), γ 77·63(2)°, Z= 2 tetramers, R0·049 for No11485, and as a chloroform disolvate, triclinic, P-1 a22·584(9), b13·979(2), c13·892(2) Å, α 68 ·99(2), β 77·31(3), γ 75·65(3)°, Z= 2, R0·041 for No8701. An unsolvated AgI complex, monoclinic, P21/c, a25·26(1), b12·506(5), c25·228(9) Å, β 113·54(4)°, Z= 4 tetramers, R0·054 for No5520, isomorphous with previously recorded [IAg(PPh3)]4(denoted ‘α’), was obtained from methanol/saturated potassium iodide solution, while a second ‘β’-form obtained from 2,4,6-trimethylpyridine, rhombohedral R3c, a17·048(7) Å, α 61·15(5)°, Z= 2 tetramers, R0·037 for No1622, is isomorphous with previously recorded [BrAg(PPh3)]4, for which a redetermination is described (R0·039 for No1289); the latter has also been obtained in the common orthorhombic Pbcnarray: a18·10(1), b2·08(1), c18·39(1) Å, Z= 4, R0·041 for No2877. A new ‘step’ form of [IAg(PPh3)]4, monoclinic, C2/c, a26·14(2), b16·340(9), c18·64(2) Å, β 114·04(8)°, R0·058 for No2107, obtained from acetonitrile and isomorphous with [BrCu(PPh3)]4(step), is also recorded. In the far-infrared spectra of [(Ph3As)4Cu4X4] bands which have been assigned to vibrations of the Cu4X4core are: 166, 150, 135, 114 (X = Br); 136, 85 cm-1(X = I; 2CHCl3solvate). The 166, 150, 135 cm-1bands in the bromide are only partially resolved. These, and the 136 cm-1band in the iodide are assigned to the T2v(CuX) mode of the Cu4X4core; the bands at 114 and 85 cm-1are assigned to the next highest frequency T2mode of the cluster. The splitting of the highest frequency T2band for the bromide is consistent with the greater degree of distortion of the Cu4X4core from ideal Tdsymmetry in this complex relative to the iodide.

1 : 2 Adducts of copper(I) chloride and bromide with triphenylarsine have been obtained as chloroform- solvated dimers [(Ph3As)2Cu(µ-X)2Cu(AsPh3)2].2CHCl3, characterized by room-temperature single- crystal X-ray studies, monoclinic C2/c, a≈ 21·4, b≈ 17·9, c≈ 19·3 Å, β ≈ 92°, Z= 4 dimers, conventional Ron Fbeing 0·041 and 0·055 for No3922 and 3130 independent ‘observed’ (I > 3σ(I)) reflections; the halogen atoms of the dimers are disposed on crystallographic 2axes, together with the associated hydrogen-bonded pair of disordered chloroform molecules. The structures form an interesting contrast with those of their silver(I)/phosphorus analogues, of similar symmetry but with aand cinterchanged, as is the metal · · · metal axis orientation which, in each case, lies parallel to the long crystallographic axis. An unsolvated nitrate [(Ph3As)2Cu(µ-O-ONO2)2Cu(AsPh3)2], monoclinic, P21/c, a14·867(8), b23·518(8), c21·86(1) Å, β 122·24(4)°, Z= 4 dimers, R0·056 for No3447, is also recorded, the structure being similar to that of its silver(I) bromide analogue. The far-infrared spectra of [(Ph3As)2Cu(µ-X)2Cu(AsPh3)2].2CHCl3(X = Cl, Br) show v(CuX) bands at 195 and 153 cm-1respectively. Shifts in the wavenumbers of the CHCl3vibrations which involve the hydrogen atom (or the deuterium atom in the corresponding CDC13compounds) are in the direction expected for hydrogen bonding of the chloroform to the halide ligand, and the magnitudes of the shifts in these and the corresponding Ph3P/AgX complexes appear to be sensitive to the degree of ionic character of the M-X bonds. A combined differential scanning calorimetry/infrared study suggests that the chloroform disolvates are converted into unsolvated compounds which have the same halogen-bridged dimeric structures as the parent compounds, with v(CuX) = 184, 141 cm-1for X = Cl, Br respectively.

Crystallization of 1 : 2 mixtures of the copper(I) halides CuX, X = Cl, Br, I, with triphenylstibine from acetonitrile yields adducts of 1 : 2 CuX/SbPh3stoichiometry, confirmed by single-crystal X-ray structure determinations. The three complexes are isomorphous, monoclinic, P21/c, a≈ 24·3, b≈ 14·2, c≈ 20 Å, β 110°, Z= 4 dimers; conventional Ron Fwere 0·047, 0·044 and 0·045 for No11247, 4673 and 10418 independent ‘observe’ (I > 3σ(I)) reflections respectively. The complexes, also isomorphous with some related species, e.g. 1 : 2 AgBr,I/AsPh3, are dimers: [(Ph3Sb)2Cu(µ-X)2Cu(SbPh3)2]. The chloride is also recorded as a chloroform disolvate, isomorphous with its arsine analogue, being monoclinic, C2/c, a21·486(9), b17· 925(9), c19·972(7) Å, β 91·31(3)°, Z= 4 dimers, R0·057 for No3756. The far-infrared spectra of [(Ph3Sb)2Cu(µ-X)2Cu(SbPh3)2] (X = Br, I) showed no clear v(CuX) bands, in contrast to the situation reported previously for the corresponding Ph3As compounds. A possible v(CuCl) band is observed in the X = Cl complex at 219 cm-1, but this occurs in a region where there is also significant absorption in the other two compounds. The absence of strong v(CuX) bands in these complexes is consistent with the situation observed previously for the 3 : 1 compounds [(Ph3Sb)3CuX].

Crystallization of some copper(I) salts, CuX, with triphenylarsine in 1 : 3 stoichiometry from acetonitrile has yielded an array of adducts, [(Ph3As)3CuX], characterized by room-temperature single crystal X-ray structure determinations. [(Ph3As)3CuCl] (1) has been characterized in two unsolvated phases, α and β, the second form previously recorded as monoclinic, P21/n, Z= 8. The ‘α’ phase, like the bromide (2) and iodide (3), adopts the trigonal P3 array, widespread among many [(Ph3E)3MX] adducts with a≈ 19, c≈ 11 Å; conventional Ron Fwas 0·037, 0·041, 0·056 for No3458, 3259, 3434 independent ‘observed’ (I > 3σ(I)) reflections for these three adducts respectively. A further form, γ, is a toluene hemisolvate, monoclinic, P21/c, a21·490(5), b10·218(7), c24·901(6) Å, β 117·53(2)°, Z= 4, R0·057 for No7207. The nitrate (4), obtained as a monosolvate from methanol, is monoclinic, P21/n, a15 ·115(9), b23·201(9), c14·170(14) Å, β 92·56(7)°, Z= 4, R0·049 for No5476. In all compounds, the copper atom is four-coordinate, E3CuX, the nitrate in (4) being -ONO2unidentate. The CuX bond lengthsr(CuX) in [(Ph3E)3CuX] (X = Cl, Br, I) show a decrease from the Ph3P to the corre3sponding Ph3As compound, and this is consistent with the observed increase in the v(CuX) wavenumbers in the far-infrared spectra. These trends are both consistent with an increase in the CuX bond strength from the Ph3P to the Ph3As complexes, and possible reasons for this are discussed.

The syntheses of adducts, [(Ph3Sb)3CuX], X = Br, I, NO3, obtained by crystallization of 1 : 3 CuX/SbPh3mixtures from appropriate solvents are described, together with their room-temperature single-crystal X-ray structure determinations. The bromide, obtained as a chloroform monosolvate from that solvent, is triclinic, P-1, a13·861(4), b14·306(4), c14·347(4) Å, α 84·40(2), β 86·93(2), γ 75·56(2)°, Z= 2 f.u., conventional Ron Fbeing 0·053 for No= 4136 independent ‘observed’ (I> 3σ(I)) reflections; this solvate is isomorphous with its previously recorded chloride counterpart. The iodide is triclinic, P-1, a14·55(1), b14·385(2), c23·626(6) Å, α 91·78(1), β 90·77(4), γ 92·54(5)°; Z= 4, R0·050 for No6917, and isomorphous with its phosphorus counterpart. The nitrate, although a methanol sesquisolvate, is also isomorphous with the chloride and bromide, a13·369(9), b14·398(3), c14· 504(12) Å, α 82·29(5), β 84·39(6), γ 75·11(4)°, R0·052 for No5672. Cu-X are (2·235(5) (Cl)), 2·366(3) (Br), 2· 556(2) ( 2 ) (I), 1·98(1) Å (ONO2), appreciably shorter than in their previously recorded EPh3, E = P, As counterparts. The far-infrared spectra of [(Ph3Sb)3CuX] showed no clear v(CuX) bands, in contrast to the situation reported previously for the corresponding Ph3P and Ph3As compounds. It is likely that v(CuCl) is masked by a strong band at 270 cm-1due to the Ph3Sb ligand. However, the region below 250 cm-1in which the v(CuX) bands are expected for the X = Br, I complexes contains no strong ligand bands. Possible reasons for the absence of v(CuX) bands in these complexes are considered.

The syntheses and room-temperature single-crystal X-ray structure determination of 1 : 3 adducts formed between silver(I) (pseudo-)halides, AgX, and triphenylarsine, AsPh3, are described (X = Cl, Br, I, SCN), [(Ph3As)3AgX], (1)–(4). The chloride (1) has been previously described as its acetone hemisolvate; other solvates (1a–d) (0·75 MeCN, MeOH, 1·5 pyridine, 0·75 2,6-dimethylpyridine) are isomorphous, being triclinic, P-1, a≈ 13·5, b≈ 14·0, c≈ 14·25 Å, α ≈ 83, β ≈ 87, γ ≈ 76°, V≈ 2600 Å3, Z= 2 f.u. The bromide (2), iodide (3) and thiocyanate (4) are isomorphous with [(Ph3P)3AgI], monoclinic, P21/n, a≈ 19·1, b≈ 14·0, c≈ 17·7 Å, β ≈ 97°, Z= 4 f.u. In the chlorides, Ag–Cl are 2·494(5)–2·525(6) Å, with appreciably different Cl–Ag–As ranges (99·7(1)–114·3(1)° in the acetonitrile solvate; 104·8(2)–110·2(1)° in the 2,6-dimethylpyridine solvate) and more compact As–Ag–As distributions (overall range: 109·93(8)–113·26(3)°). For the bromide and iodide, Ag–X are 2·627(1) and 2·779(1) Å respectively, while for the thiocyanate Ag–S is 2·550(5) Å with Ag–S–C 104·2(3)°; the latter complexes also display wide ranges for many of the associated bonding parameters about the silver atom. The far-infrared spectra of [(Ph3As)3AgX] (X = Cl, Br, I) show v(AgX) bands at 217, 145 and 124 cm-1respectively. The relationship between the v(AgX) wavenumbers and the Ag–X bond length r(AgX) is found to be the same as that for a range of AgX complexes with phosphine ligands, and is similar to that observed previously for analogous CuX complexes.

Syntheses and room-temperature single crystal X-ray structure determinations are recorded for adducts [M(EPh3)4] (ClO4), M = Cu, E = As (1), Sb (2); M = Ag, E = As (3), Sb (4), enabling comparison with analogous, previously studied MP4and MN4environments. The four complexes so characterized all crystallize in the familiar rhombohedral R-3 array (a≈ 14·4, c ≈ 52 Å, hexagonal setting) with the metal and chlorine atoms located on crystallographic threefold axes. In these arrays Cu–E (axial, off axis) are 2·493(2), 2·533(1) for (1), and 2·572(1), 2·577(1) Å for (2), the disparity in the two independent M-E distances being diminished relative to those of previously studied phosphorus analogues, perhaps in consequence of increasing E size. In (3) and (4), some cation disorder is evident in respect of the ligand pnictide atom (E); for the major components Ag-E are 2·652(3), 2·680(2) in (3); 2·732(2), 2·7295(8) Å in (4). Problems associated in defining the metal atom environment geometries in the latter are, nevertheless, more satisfactorily overcome in two further determinations of nitrate salts: [Ag(SbPh3)4] (NO3) (5) is of the rhombohedral family with no cation core disorder, Ag–E (axial, off axis) being 2·720(4), 2·725(2) Å, while the structural characterization of a 1 : 4 triphenylarsine adduct of silver nitrate is recorded as its tetraethanol solvate, namely [Ag(AsPh3)4] (NO3).~ 4C2H5OH(6), monoclinic, C2/c, a18·373(4), b20·786(5), c21·070(8) Å, β 108·18(3)°, Z= 4 f.u. The silver atom of the [Ag(AsPh3)4]+cation unusually lies on a crystallographic 2(rather than a 3) axis of the incipiently23(T) array, with Ag-As 2·649(2), 2·650(2) Å and As-Ag-As ranging from 108·22(4) to 111·41(6)°. The structure determination of a chloroform solvate of (2), denoted (2a), of low precision, is noted, together with the structure of an interesting artefact, isomorphous with the rhombohedral oxoanion array, modelled as [Ag(PPh3)4]2(SiF6).py (7). Bands in the far-infrared spectra of [M(AsPh3)4] (ClO4) are assigned to v(MAs) vibrations at 119 (M = Cu) and 103 cm¯1(M = Ag); this produces a more consistent picture of the variation in the wavenumbers of the v(ME) modes in [M(EPh3)4]+compounds than was available previously.