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The 1 H NMR spectra of C 2 H 5 InBr 2 · tmen ( 1 ) C 2 H 5 InI 2 · tmen ( 2 ) (tmen = N,N,N′,N′ -tetramethylethanediamme) and [(C 6 H 5 ) 4 P][C 2 H 5 InI 3 ] ( 3 ) show only a broad singlet for the ethyl protons at 60 MHz. Spectra run at 400 MHz resolve these into a triplet + quartet for 1 and 3 . The structure of each compound has been determined by X-ray crystallography; 1 and 2 are five-coordinate species, with InC 2 N 2 X (X = Br, I) nuclei, while 3 consists of [(C 6 H 5 ) 4 P] + cations and anions whose InCI 3 nucleus has C 3 v , symmetry.

The electrochemical oxidation of zinc, cadmium, or indium in the presence of Co2(CO)8 or Mn2(CO)10 in an organic solvent gives rise to the appropriate heteronuclear metal carbonyl M[M′(CO)n]m (M = Zn, Cd, In; M′ = Co, Mn; n = 4, 5; m = 2, 3). The advantages of this method are discussed, as is the mechanism of the processes which lead to the reaction products.

The electrochemical oxidation of magnesium into acetonitrile solutions containing alkyl or aryl halides (RX) and 2,2′-bipyridine (bipy) yields the neutral adducts RMgX · bipy. With α,ω-dihalides XR′X, the products are the corresponding R′Mg 2 X 2 · 2bipy compounds. The preparation proceeds equally well with either aryl or alkyl compounds, and with chlorides, bromides, or iodides, but the resultant adducts show none of the typical reactions of Grignard reagents other than alkane elimination with mineral acids. With solutions containing RX and R′ 4 NX, the products of electrochemical oxidation are the salts R′ 4 N[RMgX 2 · CH 3 CN], which also lack typical Grignard reagent chemistry.

The electrochemical oxidation of a nickel or palladium anode in the presence of certain organic halides yields the unstable RMX species, which can be stabilised by both mono and bidentate phosphorus(III) ligands. Cyanide compounds of the general formula RNiCN.L 2 can also be synthesised. The advantages of the method are outlined.

The molecular structure of trimethylindium has been redetermined by vapor phase electron diffraction. The independent structural parameters assuming three-fold axial symmetry based on the rg distances and their estimated uncertainties (2σ) are r(InC) = 209.3 ± 0.6 pm, r(CH) = 114 ± 3 pm, and < HCIn = 112.7 ± 0.8°. A slight nonplanarity (3.0 ± 2.5°) was attributed to a shrinkage effect in [Formula: see text] of 0.4 pm. The analysis was insensitive to the rotational position of the methyl groups relative to the InC3 frame. The root mean square amplitudes were not accurate due to a problem with the indium phase factor.

Tin reacts with tetrahalogeno-o-benzoquinones X4C6O2 (X = Cl, Br) in refluxing toluene to give the tin(IV) catecholato species Sn(O2C6X4)2, and neutral and anionic derivatives have also been obtained. A mixture of Sn + X4C6O2-o + I2 + 1,10-phenanthroline (phen) yields SnI2(O2C6X4)phen. With gallium or indium (= M), the corresponding experiments give derivatives of MII (e.g., [M(O2C6X4)phen]2), or MIII (e.g., MI(O2C6X4)phen). Intermediate paramagnetic species were detected in the case of [Formula: see text], and a reaction mechanism involving one-electron transfer processes is proposed on the basis of these results. Solvated crystals of the compound InCl(O2C6Cl4)(C6H7N)3 were obtained from CH2Cl2 solution, and the structure of this molecule has been determined by X-ray crystallographic methods. Keywords: gallium, indium, tin, benzoquinones, oxidation.

The electrochemical oxidation of either zinc or cadmium (= M) in acetone solutions of o -C 6 H 4 (OH) 2 (= R(OH) 2 ) gives M(O 2 R) in good yield. The advantages of this method are discussed. When neutral mono- or bidentate donors are present in the solution, the products are the 1:2 or 1:1 adducts of M(O 2 R). Similar results ar reported for 2,3-dihydroxynaphthalene and 2,2′dihydroxybiphenyl. A preliminary crystal structure determination on Zn(O 2 C 6 H 4 )(phen) 2 ·2C 6 H 4 (OH) 2 (phen) = 1.10-phenanthroline) shows the presence of a ZnO 2 N 4 kernel; each oxygen atom of the catecholate ligand is hydrogen-bonded to both hydrogens of a neutral C 6 H 4 (OH) 2 molecule.

In(SPh)3 is readily prepared by the reaction of InCl3 and NaSPh in methanol. The compound is a Lewis acid, forming 1:1 adducts with 2,2′-bipyridine, 1,10-phenanthroline, N,N,N′,N′-tetramethylethanediamine, bis(diphenylphosphino)ethane, and dimethylsulphoxide, and 1:2 adducts with pyridine, trimethylamine, and triphenylphosphine. Reaction with R4NX (X = Cl, Br, I) or similar salts gives R4N[XIn(SPh)3] salts, which are 1:1 electrolytes. The structure of Ph4P[BrIn(SPh)3] has been determined by X-ray methods. The crystals are monoclinic, space group P21/c, with cell dimensions a = 9.964(3) Å, b = 13.477(3) Å, c = 30.359(7) Å, α = 98.30(2)°, Z = 4, R = 0.0622 for 2924 unique observed reflections. The anion has distorted tetrahedral symmetry in the InBrS3 kernel, with In—Br = 2.527(2) Å, and In—S(av) = 2.450 Å. The vibrational spectra of In(SPh)3 and its derivatives in the region 500–200 cm−1 are discussed.

The cadmium β-diketonate complexes Cd(RCOCHCOR′)2 (R = CH3, R′ = CH3; R = CF3 R′ = CH3, i-C3H7, i-C4H9, t-C4H9, C6H5, 2-naphthyl) can be prepared in good yield by the direct room temperature electrochemical oxidation of the metal into a solution of the parent diketone in acetonitrile. Adducts of the type Cd(RCOCHCOR′)2L (L = 2,2′-bipyridine, 1,10-phenanthroline, N,N,N′,N′-tetramethylethylenediamine) can be prepared insitu, or by subsequent addition of the ligand to the electrolytic solution. X-ray studies show that the molecular structure of both Cd(acac)2phen and Cd(CF3COCHCOC6H5)2phen is based on a CdO4N2 kernel, distorted from octahedral stereochemistry by the bite of the ligands.

The salts [(C2H5)3NH]2[M4(SC6H5)10] (M = Zn, Cd) can be prepared by the electrochemical oxidation of the metal in an acetonitrile solution of triethylamine and benzenethiol. An X-ray crystal structure determination shows that the anion consists of a tetrahedron of metal atoms, each carrying a terminal -SC6H5 ligand, and connected to the three other metal atoms by bridging > SC6H5 groups. The results are compared with those for similar compounds reported in the literature.

The electrochemical oxidation of zinc or cadmium into acetonitrile solutions of RC 6 H 4 X (R  CN, NO 2 ; X  Cl, Br, I; not all combinations) gives the corresponding RC 6 H 4 MX compounds, which form stable 1 : 1 adducts with 2,2′-bi-pyridine. The method provides a simple and direct synthesis of these and related compounds.

A convenient electrochemical synthesis of various ML2, ML3, ML4 and MOL2 complexes (M = Ti, Zr,Hf, V,Cr, Mn,Fe, Co,Ni, Cu,In; L = acetylacetonate anion, 3-hydroxy-2-methyl-4-pyronate anion, 2-acetylpyrrolate anion, and other bidentate ligands) is described. The metal, as the anode of simple cell, is oxidised in the presence of the parent compound of the ligand (HL) in an organic solvent mixture. Gram quantities of complex can be produced in a few hours; other advantages of this method are discussed. Current efficiency measurements serve to identify the reaction mechanism.

The X-ray photoelectron spectra (metal and halogen energy levels) have been recorded for binary halides of indium in the +I, +II, and +III states, and for anionic halide complexes of indium(I) and (III). The results are internally consistent in terms of the relation between metal and ligand levels, but lattice effects prevent any detailed interpretation of indium levels in terms of oxidation state, ligand electronegativity, and/or coordination number.

CNDO calculations have been carried out for the molecule InC5H5 of C5υ symmetry. Overlap populations were calculated and compared with those for related species. The bonding between In and the organic moiety can be described as essentially a covalent interaction involving mainly indium 5s and 5p orbitals with ring pπ orbitals. A lone pair on indium is a dominant feature of the structure, and is largely responsible for a (calculated) dipole moment of 4.75 D. The calculated orbital energies are compared with experimental photoelectron spectra.

The reaction of indium(I) halides (InX; X = Cl, Br, I) with tetrahalogeno-ortho-quinones (Y4C6O2; Y = Cl, Br) gives the oxidative addition product Y4C6O2InX, These compounds have been isolated as adducts with neutral bidentate donor ligands (N,N,N′,N′-tetramethylethanediamine (tmen), 1,10-phenanthroline) or as salts of the anionic complexes [Y4C6O2InCl2]− or [Y4C6O2In(Cl)Br]−. The number of coordinated tmen molecules, and hence the structure, depends on the method of preparation. Infrared, 1H NMR, and 13C NMR spectroscopy all confirm that these products are all substituted-catecholato derivatives of indium(III), and the structure of these various neutral or anionic derivatives is discussed. The temperature dependence of the 13C NMR spectra shows that the dynamic behaviour of these compounds (in d6-dmso) is similar to that observed in previous studies of indium(III) chelate complexes.

Field ionisation/field desorption mass spectra are reported for Mn2(CO)10, Cd[Co(CO)4]2 and some adducts, In[Co(CO)4]3, bipy•Zn[Co(CO)4]2, and bipy•M[Mn(CO)5]2 (M = Zn, Cd). The spectra are extremely simple, and the small number of easily identified species includes the molecular ion in some cases. The relative abundance of the fragments is discussed in terms of known stabilising factors in such compounds. No spectra could be obtained from Co2(CO)8 or Fe2(CO)9, which may be the result of their carbonyl-bridged structures.

The electrochemical oxidation of a metal anode in a non-aqueous solution of dpaH (dpaH = 2,2′- dipyridylamine) under nitrogen gives M(dpa) n complexes in high yield (M = Cu, Ag, T1, n = 1; M = Zn, Cd, n = 2). In the presence of O 2 , copper yields Cu(dpa) 2 . When the oxidations were repeated in the presence of neutral ligands, adducts were only obtained for Cu I with phosphine donors. Both Cu(dpa) and Cu(dpa) 2 react with CS 2 to give dithiocarbamate complexes, as do the Ph 3 P and dppe adducts of Cu(dpa) (dppe = 1,2-bis(diphenylphosphino)ethane). The thallium(I) compound undergoes ligand exchange with C 6 H 5 OH, C 6 H 5 SH or C 5 H 11 SH to give TlOR or TlSR.

The reaction between SnX2 (X = Cl, Br, I), 1,10-phenanthroline (phen) and Y4C6O2 (Y = Cl, Br) yields Y4C6O2SnX2•phen with the o-quinone being converted to the corresponding catecholate anion. Reactions in which phen is replaced by Me2NC2H4NMe2 (tmen) are more complex, and the products depend in part on the solvent. These products include Cl4C6O2SnCl2•tmen, and products arising from solvation by ROH (R = CH3, C2H5). An X-ray crystallographic study of (tmenH)2[Sn(O2C6Cl4)3] shows that the anion contains a six-coordinate tin atom bonded to substituted catecholate anions. Hydrogen-bonding between cation and anion appears to be an important factor in the stability of the lattice.

Cristallisation dans le systeme triclinique, groupe P1 et affinement jusqu'a R=0,039. Les molecules sont planes et centrosymetriques

Adducts of bis(diphenylphosphino)methane (dppm) with copper(I) thiolates can be prepared by oxidizing anodic copper into an acetonitrile solution of dppm and RSH (R = n-C4H9, C5H11, C6H5, o,m,p-CH3C6H4, 2-naphthyl). The products are (CuSR)2·dppm for R = n-C4H9, C5H11 or C6H5, and CuSR·1.5dppm for R = o-CH3C6H4 or 2-naphthyl. No adducts were obtained for R = m- or p-CH3C6H4. Reaction between (CuSC5H11)2·dppm (C5H11 = C2H5C(CH3)2−) and CS2 gives the insertion product CuS2CSC5H11 · dppm. An X-ray crystallographic study of (CuSC5H11)2·dppm reveals the presence of a novel Cu4S4 ring, in which sulphur atoms are below a Cu4 plane; this Cu4S4 ring is capped by two six-membered Cu2SCP2 rings in the boat form.

The electrochemical oxidation of copper, silver, or gold into acetonitrile solutions of benzyl chloride or hydrogen halide plus triphenylphosphine leads to the formation of the adducts MXLn (M = Cu, Ag, Au; X = Cl, Br, I; L = Ph3P; n = 1, 1.5, 2; not all combinations). The value of n depends markedly on the mole ratio Ph3P:dissolved metal. The reaction pathway is discussed in the light of measurements of current efficiency. The results of X-ray structural studies of AuCl•L and AuClL2 are briefly reported.

Etude de la reaction dans la solution toluene |CH 2 Cl 2 |tmen (tmen=N,N,N',N'-tetramethylethanediamine) a basse temperature (

The electrochemical oxidation of Zn, Cd or Hg (= M) in a non-aqueous solution of Ph 3 SnCl yields the metal-metal bonded insertion product Ph 3 SnMCl which can be easily isolated as an adduct present in the solvent phase. The mechanism of this direct electrochemical synthesis is discussed. The far infrared spectra (500–50 cm −1 ) of these compounds are also reported.

The reactions of 1,4-dilithio-1,2,3,4-tetraphenylbutadiene with indium(III) species have been investigated. The neutral compound InCl 3 . 3py (py = p

Indium(I) halides (InX) react with Ph 3 SnX (X = Cl, Br, I) in toluene/tmed mixtures to give Ph 3 SnInX 2 ·tmed compounds (tmed = N , N , N′ , N′ -tetramethylethanediamine), and Ph 3 Sn(OAc) yields Ph 3 SnIn(OAc)X 2 ·tmed. Vibrational spectra and conductivities of these compounds, and of the salt Et 4 N[Ph 3 SnInCl 3 ], show that these are the first examples of SnIn bonded molecules. With Me 3 SnCl, Ph 3 SnH, Ph 3 GeCl, Ph 3 PbCl and Ph 2 PCl, no oxidative addition reaction was observed. The results are compatible with previous discussions of the mechanism of such reactions, based on the insertion of indium into the MX bond.

Cadmium(II) chloride reacts with toluene-3,4-dithiol (H2TDT) to give Cd (TDT), which is apparently a homopolymer in the solid state. Adducts with neutral monodentate and bidentate donors have been prepared. The structure of the salt (Ph4As)2 [Cd(TDT)2] was determined by X-ray crystallography. Crystals of this compound are monoclinic (P21/c), with a = 23.032 (4) Å, b = 12.396(4) Å, c = 22.529(5) Å, β = 111.106(2)°. The structure was refined by least-squares methods to a final R-valueof 0.0469 for 2523 "observed" reflections. The anion is a distorted tetrahedral, mononuclear species with Cd—S bond distances ranging from 2.488(5) Å to 2.531(4) Å. This anion is also a Lewis acid, forming complexes of the type [Cd(TDT)2L]2− with neutral bidentate ligands.

The copper(I) thiolate CuSC5H11 (CuSR; R = C(CH3)2CH2CH3) dissolves in carbon disulphide to yield Cu8(SR)4(S2CSR)4. The crystal structure of this substance is monoclinic, with a = 31.532(26), b = 20.700(6), c = 23.725(10) A, β = 114.16(3)°, V = 14129(13) A3, Z = 8 and space group C2/c. The molecule is a complex cage of copper atoms ligated by RS and RSCS2 ligands. The structure breaks down on thermal loss Of CS2 or on electrochemical oxidation. Reaction with PPh3 or PPhCy2 (Cy = cyclohexyl) gives the 1 : 2 adducts of CuS2CSR, which are also unstable to loss Of CS2.

The electrochemical oxidation of anodic uranium into acetonitrile solutions of X 2 (X = Cl, Br) under nitrogen gives rise to UCl 4 ·4CH 3 CN or UBr 4 ·2CH 3 CN in good yield. These compounds are easily converted to other UX 4 adducts. In the presence of oxygen, solutions of UO 2 X 2 are produced by the electrolysis, and the parent halide, or neutral addition compounds, are readily obtained from these. Addition of R 4 NX to the cell results in the direct synthesis of (R 4 N) 2 UX 6 under nitrogen, or (R 4 N) 2 UO 2 X 4 under oxygen. The only iodo compound which could be formed by electrolysis into N,N- dimethylformamide (=dmf) was UI 4 ·4dmf.

The electrochemical oxidation of anodic copper or silver (= M) into non-aqueous solutions of RSH (R = alkyl, axyl) gives MISR as insoluble materials in high yield. In the presence of 1,10-phenanthroline (= L), the products are MISR•phen for M = Cu, but not Ag. Gold resists oxidation under such conditions, and AuISR (R = n-C4H9, C6H5) was obtained in only poor yield. The crystal structure of the solvated dimeric adduct [Cu(SC6H4CH3-o)•phen]2•CH3CN is triclinic, with a = 10.682(3) Å, b = 11.729(4) Å, c = 15.608(5) Å, α = 76.87(2)°, β = 76.35(2)°, γ = 68.07(2)°, V = 1742(1) Å3, Z = 2 and space group [Formula: see text]. The structure is based on a folded Cu2S2 ring with an unusually short Cu—Cu distance of 2.613(3) Å Each copper atom has CuS2N2 pseudo-tetrahedral stereochemistry, with Cu—S = 2.337 Å(av) and Cu—N = 2.10 Å(av).

The electrochemical oxidation of anodic zinc into a solution of PhSH + Et3N in CH3CN yields *Et3NH)2[Zn4(SPh)10]. The structure, as determined by X-ray crystallography, shows that the anion is a novel cluster based on a tetrahedral Zn4S10 kernel.

A simple preparation of the title compound, its crystal structure, and nmr spectra are reported. The compound crystallizes in the space group P21/n, with a = 8.109(2) Å, b = 16.183(4) Å, c = 11.968(4) Å, β = 93.45(2)°, V = 1567.7(7) Å−3, ρ = 1.987 g cm−3, Z = 4 (MoKα, λ = 0.71069 Å). The structure was solved by the heavy atom method and refined to the final R = 0.0415 for 1261 "observed" reflections. The structure consists of five-membered cyclic C7H18N22+ cations, iodide anions, and methylene dichloride molecules which are held loosely in the lattice.

The electrochemical oxidation of thorium into solutions of halogen (X2; X = Cl, Br) in acetonitrile yields the adducts ThX4•4CH3CN in good yield. With solutions of X2 + R4NX, the products are (R4N)2ThX6. Neutral chelate complexes such as Th(acac)4 (acac = 2,4-pentanedionate) can also be prepared in a one-step synthesis from the metal, but cationic complexes could not be obtained by electrochemical methods.

The molecular structure of dicholoro(acetylacetonato)-2,2′-bipyridylindium(III) has been determined from three dimensional X-ray data collected by counter methods. The structure has been refined by least-squares techniques to a conventional R factor of 4.3% for the 3524 observed reflections. Crystals of Cl2In(acac)(bipy) are monoclinic, a = 11.340(3), b = 12.198(3), c = 14.330(3) Å, β = 120.25(2)°, z = 4, space group P21/c. The chloride ligands are cis, with In—Cl at distances of 2.443(1) and 2.394(1) Å; the In—O bond lengths are 2.124(3) and 2.164(3) Å, and the In—N bond distances are 2.276(4) and 2.299(4) Å.

Cobalt(II) and nickel(II) thiolates, M(SR)2, can be prepared in high yield by the electrochemical oxidation of a metal anode in an acetonitrile or acetone solution of RSH (R = C6H5, o-CH3C6H4, 2-C10H7, 2,3,4,5-C6F4H; not all combinations). When 2,2-bipyridine or 1,10-phenanthroline (=L) is added to the electrolyte phase, the products are the adducts M(SR)2L2. In the case of Co(SC6H5)2(phen)2, aerial oxidation leads to the formation of the cobalt(III) cation [Co(SC6H5)2(phen)2]+, isolated as the perchlorate salt. X-ray crystallographic analysis showed that this cation has a cis-CoS2(N2)2 kernel.

The neutral indium(II) compounds In2X4(Et3P)2, In2X4(TMED)2, and In2X4(TMED)2C6H6 (X = Br, I; TMED = N,N,N′,N′-tetramethylethylenediamine) have been prepared by the reaction of InX2 and donor in benzene or toluene. With several other neutral donors, and in all systems involving InCl2, decomposition to In0 is the predominant process. Analysis of the vibrational spectra demonstrates that these structures involve X2In-InX2 kernels. Slight revisions are proposed to previous discussions of the infrared spectra of In2X62− anions.

The bis-pyridine adduct of In(SC6H5)3 has been prepared. A crystal structure determination shows that the molecule has two different conformations in the solid state, related to the orientations of the phenyl rings of the SC6H5 ligand. The crystalline form of In(SeC6H5)3 is a homopolymer in which six-coordinate indium atoms are linked through bridging selenium atoms. The phenyl groups of the SeC6H5 ligand show an interesting disorder pattern. The structure of In(SC6H5)3 is discussed in this context.

Mr=465.1, orthorhombic, Pna2~, a= 20.069 (6), b= 10.633 (3), c=9.050 (2) A, V= 1931 (1) A 3, Z = 4, D x = 1.599, D m = 1.59 gcm -3, 2(Mo K~t) = 0.71069 A, p = 13.9 cm -1, F(000) = 920, T-- 295 K. Final R = 0.023 for 1362 unique observed reflections. The possible modes of bonding of the benzoate anion to In are discussed; a three-centre orbital interaction is proposed. Introduction. In a recent paper (Peppe, Tuck & Victoriano, 1982) we have described some of the synthetic applications of solutions of indium(I) halides in non-aqueous media. One reaction of particular interest corresponds formally to the oxidative insertion of InX (X= CI, Br or I) into an A-B bond to give species A InX(B). Although such reactions with alkyl halides (i.e. A-B = C-X) were reported some years ago (Waterworth & Worrall, 1971; Poland & Tuck, 1972), the availability of the solution-phase reaction has now allowed us to extend these investigations to substrates involving elements of Group V and VI. The products of the reaction between InC1 and dibenzoyl peroxide in dichloromethane/pyridine solution included the title compound CI2In(O2CC6Hs)py 2 (py = pyridine). We have established the structure of this substance by X-ray crystallographic methods. The results allow some interesting comparisons with results for pre- viously studied indium(III) complexes, and lead to a discussion of the bonding between In and the carboxy- late ligand. Experimental. Equimolar quantities of indium(I) chloride and dibenzoyl peroxide (ca 5 mmol) were mixed with 50 ml dichloromethane at 193 K. Pyridine (4 ml) was then added and the temperature allowed to rise slowly to ambient; after being stirred for 5 d, the reaction mixture was a deep-red solution over a brown solid. Addition of diethyl ether to the solution caused the precipitation of further brown solid, which was removed by filtration. The resultant solution slowly deposited a yellow solid, which was removed, and on further standing the filtrate deposited colourless acicular crystals of C12In(OzCC6Hs)py2, whose com- position was established by elemental analysis and * To whom correspondence should be addressed.

Chemical shift data and conductivities of acetylacetonates of some group IA, IIA, and IIIA metals in dimethylsulfoxide are recorded. It is concluded that nuclear magnetic resonance spectra cannot give definite information on π-bonding in these complexes, though the results for the group III elements are consistent with the presence of such bonds, as is the evidence from related spectroscopic studies.

The electrochemical oxidation of copper in the presence of RX (R = CH3, C6H5, C6H5CH2; X = Cl, Br, I, not all combinations) and either 2,2′-bipyridine or (C2H5)4NX gives rise to neutral or anionic copper(I) halide complexes. The current efficiency shows that CuX is produced at the anode; the subsequent solution chemistry influences the complex formation processes.

CH3)3NHIaInC16, M r = 507.9, tetragonal, 14Jacd, a = 22.464 (4), c = 17.551 (3) /~,, F = 8856.78 )k 3, Po = 1.52, Pc = 1.52 g cm -3, Z = 16, Mo Ka 1 radiation, 2 = 0.70926 A, g(Mo Ka) = 17.68 cm -~, R = 0.064 for 722 observed reflexions, t = 25°C. The structure is composed of Me3NH ÷ and InCl,- ions. The InCl,- ions are octahedral (In-C1 2.521 ,~) and occupy crystallographic centres of sym- metry. The M%NH + ions are of two types; half are in general positions, while the remainder fill disordered positions near a crystallographic twofold axis. Introduction. Crystals of the title compound are colourless parallelepipeds elongated along c. The space group was determined from Weissenberg photographs of layers hkO-hk3 and precession photographs of layers hOl-h3l and hhl taken with Cu Ka radiation (2 = 1.5418 A). The space group I4t/acd was determined from the systematic absences hkl when h + k + l = 2n + 1, hk0 when h = 2n + 1, Okl when l = 2n + l, and 001 when 2n + l 4: 4n. Reflexions for which hkl had h, k, l = 2n and h + k + l = 4n were, in general, very much stron- ger than the rest. A crystal, 0.20 × 0.24 × 0.40 mm, sealed in a Lin- demann-glass capillary was used for the determination of cell dimensions and for intensity collection (Mo Kay, 2 = 0.70926 ,~). To minimize multiple scattering, c* was offset approximately 12 ° from the tp axis of the diffractometer. Cell dimensions were determined from

The electrochemical oxidation of metal anodes in an acetonitrile solution of Ph2PH yields M(PPh2)(M = Cu, Ag, Au) or M(PPh2)2(M = Co, Zn, Cd); with a solution of Ph2PH and bis(diphenylphosphino)methane (dppm), this method gives Cu4(PPh2)4(dppm)2 whose structure is found to be very similar to that of Cu4(SC5H11)4(dppm)2.

Vanadium metal dissolves rapidly in a cell Pt/X2 in CH3CN/V (anode) (X = Cl, Br, I) under applied voltages of 5–50 V. The solution phase yields crystalline VCl2. 2CH3CN, VBr2. CH3CN, or VI2; the acetonitrile adducts decompose to VX2 on heating in vacuo. Overall yields of VX2, based on weight of metal dissolved, are 80–90%.