Search

Opaque blue crystals of a new mixed valence cerium germanate have been prepared at elevated temperatures (1555 K) under careful thermoanalytical control. Single crystal structure analysis shows three different types of germanate anions [GeO4]4-, [Ge2O7]6- and [Ge3O10]8-, all ger­manium atoms being in tetrahedral coordination. Due to the larger number of oxygens per unit cell (Ce2Ge2O7.2), with all the oxygens unambiguously located by X-ray single crystal structure analysis, this phase differs significantly from the corresponding cerium(III) germanate Ce2Ge2O7, which shows [GeO4]4- and [Ge3O10]8-, but no [Ge2O7]6- ditetrahedral groupings.

[Ru4(μ4-PPh)2(μ2-CO)(CO)10], in which an essentially square planar array of ruthenium atoms is capped by two phenylphosphinidene groups, readily and reversibly adds carbon monoxide to afford the tridecacarbonyl derivative [Ru4(μ3-PPh)2 (CO)13] ; crystal structure determinations on this compound and its arsenic analogue reveal that the CO addition is accompanied by a re arrangement of the cluster framework, and that these compounds can be considered as dirivatives of [Ru3(μ3-XPh)2(CO)9] (X  P or As) in which an Ru(CO)4 unit has been inserted into one of the three RuP or RuAs bonds.

The chloroarsinidene complexes (CO)5Cr⎓As(Cl)⎓Cr(CO)5 (I) and Cp(CO)2-Mn⎓As(Cl)⎓Mn(CO)2Cp (III) react with R3Al (R ⎓ alkyl, aryl) to give (CO)5Cr⎓As(R)⎓Cr(CO)5 (II) and Cp(CO)2Mn⎓As(R)⎓Mn(CO)2Cp (IV), respectively. The alkylarsinidene complexes obtained in this way for the first time are intensely coloured crystalline compounds, which contain trigonally planar coordinated arsenic(I) as shown by X-ray analysis of i-C4H9As[Cr(CO)5]2 (IIb). Reaction of Na2M2(CO)10 with RAsCl2 (R ⎓ alkyl; M ⎓ Cr, W) is another route to the alkylarsinidene compounds RAs[M(CO)5]2. Similarly AsCl3 and Na2Cr2(CO)10 react to give the chloroarsinidene complex I. The heterometallic arsinidene complex (CO)5Cr⎓As(Cl)⎓Mn(CO)2Cp (VIII) is obtained by thermally induced comproportionation from I and III. Like other chloroarsinidene complexes it reacts with tropolone to give an arsenic(I) chelate (IXa) stabilized by complexation. The structure of IXa has been determined by X-ray methods. In the presence of a base reaction of VIII with water leads to [(CO)5Cr] [Cp(CO)2Mn]AsOAs[Mn(CO)2Cp] [Cr(CO)5] (Xa). Under similar conditions I and III give analogous homometallic derivatives of As2O, an arsenic(I) oxide, not known in the free state. An X-ray analysis of [MeCp(CO)2Mn]2AsOAs[Mn(CO)2CpMe]2 (Xb) shows that in compounds X both arsenic atoms have a trigonal planar configuration. The arsenic atoms in X are thus coordinatively unsaturated and will add Lewis bases to give adducts like [(CO)5Cr]2As(PPh3)OAs(PPh3)[Cr(CO)5]2 (XI).

In (LnM)2X-Hal compounds which contain a trigonally planar coordinated bridging element (X = P, As, Sb) stabilized by two 16-electron LnM fragments the halogen may be substituted by monovalent organometallic groups. In the resulting molecules the bridging X atoms are coordinated to three metal atoms in a trigonal planar fashion. The syntheses and properties of 12 species of this type (I–IX) are described. The reaction of Na2W2(CO)10 with XCl4 (X = Ge, Sn) leads to [(Co)5W]3(μ3-X) compounds containing trigonally planar coordinated Ge (X) and Sn (XI), respectively. The trigonal planar coordination of the Main Group elements X is confirmed by eight X-ray analyses.

Photochemical reaction of thiols RSH or disulfides RSSR with W(CO)6 gives dinuclear complexes [W(CO)4(μ2-SR)2]2 and trinuclear open chain compounds (CO)4(μ2-SR)2W(CO)2(μ2-SR)2W(CO)4. Syntheses and properties, including solid state structures as determined by X-ray methods are described.

The complex [K(18-crown(6))][(PhSbI2)4I] (I) is obtained from the reaction of (CO)5CrPhSbI2 with K/18-crown(6). The central I− of the anion of 1 is coordinated by four PhSbI2 units in a square-planar fashion. The SbI2 parts of these ligands integrate to give an almost planar matrix via unsymmetrical SbISb bridges. The Ph groups of the centrosymmetric anion stick out on either side of this plane. EHT methods show that this unconventional square-planar coordination of I−, partly due to lattice effects, is stabilized by four 2-electron donor ligands.

Reactions of primary phosphines RPH2 (R = p-CH3OC6H4, p-BrC6H4) with Ru3(CO)12 yielded clusters of the type [(μ2-H)2Ru3(CO)9(μ3-PR)] and [Ru3-(CO)9(μ3-PR)2]. The reaction of C6H5AsH2 with Ru3(CO)12 gave [(μ2-H)2Ru3-(CO)9(μ3-AsC6H5)] and [Ru2(CO)6(μ2-As(C6H5)H)2]. All the compounds have been studied by IR and NMR (31P and 1H) spectroscopy and the structure of [(μ2-H)2Ru3(CO)9(μ3-P(p-CH3OC6H4))] has been determined by single crystal X-ray diffraction (R = 0.05). The overall molecular geometry is that of a trigonal pyramid with the phosphorus atom at the apex and two of the three basal RuRu bonds bridged by hydrogens. The average RuRu, RuP and RuC distances are 2.903 A, 2.289 A and 1.941 A, respectively.