Susan Jagner

On the coordination number of the metal in crystalline halogenocuprates(I) and halogenoargentates(I)

Publisher Summary This chapter presents a summary on the various structural motifs documented for halogenocuprate(I) and halogenoargentate(I) ions in the solid state, placing special emphasis on the variations in the coordination number of the metal. Anionic configurations in crystalline halogenocuprates(I) and halogenoargentates(I) appear to be strongly dependent on the nature of the cation, thus permitting, in principle, the preparation of a species, containing copper(1) or silver(I), with a desired coordination number by pertinent choice of cation. The interpretation and correlation of spectroscopic properties, in the context of structure and bonding, for compounds of group IB and group IIB metals, have been discussed in the chapter. Solid-state structures documented hitherto for halogenocuprate(I) and halogenoargentate(I) ions are described in the order of increasing coordination number of the metal. Possible correlations between the coordination number of copper(I) or silver(I) in the anion and properties of the cation with which it is coprecipitated, such as size, shape, and exposure of the positive charge, are also discussed. The most widespread method of preparation is reaction between the metal(I) halide and the halide salt of the appropriate cation dissolved in an organic solvent.

Lanthanide alkoxides. III: Four-coordinate anionic neodymium(III) alkoxides and amides

Abstract Tetracoordinate anionic neodymium(III) alkoxides and amides are obtained by adduct formation of Nd[OC(tBu)3]3 (1) and Nd[N(SiMe3)2]3 (2) with either LiCl or LiOSiMe3. The compounds (THF)3Li(μ-Cl)Nd[OC(tBu)3]3 (3), (THF)3Li(μ-Cl)Nd [N(SiMe3)2]3 (4) and [Li(THF)4][(Me3Si)2N3Nd(OSiMe3)] (5) have been characterized by single-crystal X-ray analyses.

Synthesis and molecular structure of Nd5(μ5-O)(μ3-OR)2(μ2-OR)6(OR)5(ROH)2 (R = Pri). The first example of a trigonal bipyramidal metal oxoalkoxide

Abstract Reaction between neodymium chips and isopropanol (Pri) led to the isolation of an oxoisopropoxide solvate Nd5(OPri)13(PriOH)2, which has been characterized by microanalysts and IR spectroscopy, as well as by X-ray diffraction. The molecule corresponds to a trigonal bipyramidal oxoalkoxide Nd5(μ5-O)(μ3-OR)2(μ2-OR)6(OR)5(ROH)2 (R = Pri), in which all metals achieve hexacoordination. The two alcohol molecules are linked to the same neodymium centre, thus leading to distortion of the M5O16 core.

A novel tetranuclear iodoargentate(I) ion, [Ag4I8]4-, with a cubane-type core

Abstract A novel tetranuclear iodoargentate(I) anion, [Ag4I8]4−, with a cubane-type Ag4I4 core has been isolated as the tetrapropylammonium salt and characterised by means of crystal structure determination. There are two crystallographically independent anions, each of which is situated around a two-fold axis. One of the terminal iodide ligands in one such [Ag4I8]4− anion is disordered, as are two of the tetrapropylammonium cations. The ordered terminal AgI bonds range from 2.748(2) to 2.765(2) A and the bridging AgI from 2.897(2) to 2.932(3) A, all four silver(I) centres exhibiting distorted tetrahedral coordination geometry. The compound crystallises in the monoclinic space group C2, with a=26.836(6), b=12.535(4), c=24.509(6) A, β=118.54(2)°, V=7243(4) A3, at −120 °C, and Z=4. Full-matrix least-squares refinement yielded a final R=0.042 (Rw=0.045) for 333 parameters and 3784 observed reflections.

Indanetricarbonylchromium: the effects of 1-syn- and 1-anti substituents on the regioselectivity of nucleophilic addition. Crystal structures of 1-syn- and 1-anti- methoxyindanetricarbonylchromium

A series of diastereomeric syn and anti Cr(CO)3 complexes of 1-substituted indanes have been prepared by thermolysis of Cr(CO)6 or by arene exchange with naphthalene-Cr(CO)3 (3). The regioselectivity of nucleophilic addition of a-nitrile carbon nucleophiles to syn and anti 1-R-indane Cr(CO)3 complexes (R = OMe 4, Me 10) has been investigated and compared with that of analogous reactions with indaneCr(CO)3 (1). The results of an X-ray study of syn- and anti-4 are presented. Nucleophilic additions are shown to be sensitive to the steric and electronic effects of the benzylic substituent and the nucleophile. When the reaction mixtures are warmed to 0°C, equilibration of the regioisomeric cyclohexadienyl intermediates takes place.

cis- and trans-Bis(benzoylacetonato)pyridinecopper(II): co-crystallisation of isomers and reversible pyridine loss with retention of crystallinity

The pyridine adduct of bis(benzoylacetonato-O,O′)copper(II) crystallises in both its cis- and trans-isomers within the same crystal. Copper(II) exhibits square pyramidal coordination geometry in both isomers with weak coordination of pyridine. The square planes of the isomers are mutually orthogonal, forming a square grid, in the channels of which the pyridine molecules are stacked, approximately perpendicular to the c-axis. Pyridine is readily lost from crystals unprotected by pyridine solvent, forming a crystalline powder. This powder absorbs pyridine vapour to reform microcrystalline bis(benzoylacetonato)pyridinecopper(II).

Three‐Coordinate [CuIIX3]− (X=Cl, Br), Trapped in a Molecular Crystal

Mixtures of [Ph(3)PNPPh(3)](+)Cl(-) with CuBr(2) (or CuBr(2)+CuCl(2)) in ethanol/dichloromethane yield crystals containing three-coordinate copper(II) with mixed chloride and bromide ligands, namely [Ph(3)PNPPh(3)](+)[CuCl(0.9)Br(2.1)](-) (1) and [Ph(3)PNPPh(3)](+)[CuCl(2.4)Br(0.6)](-) (2). The trigonal-planar coordination of copper(II) is angularly distorted but unambiguous, as there is no other halide ligand within 6.7 A of the copper atom. Density functional theory (DFT) calculations on planar [CuClBr(2)](-) show that the energy surface for angle bending is very soft. Crystallisation in the presence of CH(3)CN yields [Ph(3)PNPPh(3)](+)[CuCl(0.7)Br(2.3)(NCCH(3))](-) (3), in which there is additional secondary coordination by NCCH(3) (Cu-N 2.44 A). DFT calculations of the potential energy surface for this secondary coordination show that it is remarkably flat (<3 kcal mol(-1) for a variation of Cu-N by 0.8 A). The crystal packing in 1, 2 and 3, which involves multiple phenyl embraces between [Ph(3)PNPPh(3)](+) ions and numerous C-H...Cl and C-H...Br motifs, is associated with intermolecular energies that are larger than the variations in intramolecular energies. For reference, the crystal structures of [Ph(3)PNPPh(3)(+)](2)[Cu(2)Cl(6)](2-) (4) and [Ph(3)PNPPh(3)(+)](2)[Cu(2)Br(6)](2-) (5) are described. We conclude 1) that three-coordinate copper(II) with monatomic halide ligands, although uncommon, can be regarded as normal, 2) that steric control by ligands is not necessary to enforce three-coordination, 3) that a hydrophobic aryl environment stabilises [Cu(Cl/Br)(3)](-), and 4) that the energy change in the transition from three- to four-coordinate copper(II) is very small (ca 5 kcal mol(-1)).

Preparation and characterisation of tetraphenylphosphonium and tetraphenylarsonium halogenoargentates(I), including a new lodoargentate(I) cluster, [Ag4I8]4–, containing three- and four-co-ordinated silver(I)

A new iodoargentate(I) cluster [Ag4I8]4–, containing three- and four-co-ordinated silver(I) has been isolated with the tetraphenylphosphonium and tetraphenylarsonium cations and characterised by means of crystal structure determination. Tetrakis(tetraphenylphosphonium) and tetrakis(tetraphenylarsonium) hexa-µ-iodo-di-iodotetra-argentate(I)[(1) and (2)] are isostructural and crystallise in the triclinic space group P, with a= 13.453(7), b= 16.607(9), c= 11.068(7)A, α= 102.83(4), β= 103.94(4), γ= 82.96(4)°, Z= 1, and a= 13.446(3), b= 16.712(3), c= 11.293(4)A, α= 103.36(2), β= 103.84(2), γ= 83.43(2)°, Z= 1, respectively. The initial phases crystallising from solution during formation of [PPh4]4[Ag4I8] and [AsPh4]4[Ag4I8] are [PPh4][Ag3I4](3) and [AsPh4][Ag3I4](4), respectively. The latter compounds are also isostructural with one another and crystallise in the monoclinic space group P21/c with Z= 4 and a= 13.380(5), b= 26.536(5), c= 8.504(4)A, β= 108.09(4)° for (3), and a= 13.448(7), b= 26.723(4), c= 8.546(4), β= 107.99(4)° for (4). With tetraphenylarsonium as cation, discrete chloroargentate(I) and bromoargentate(I) anions, [Ag2X4]2–, X = Cl (5) or Br (6), containing distorted trigonal-planar co-ordinated silver(I), have been obtained. Bis(tetraphenylarsonium)di-µ-chloro-dichlorodiargentate(I)(5) and bis(tetraphenylarsonium) di-µ-bromo-dibromodiargentate(I)(6) both crystallise in the monoclinic space group P21/n with Z= 2 and a= 14.280(6), b= 8.200(4), c= 19.118(8)A, β= 101.19(3)°, and a= 14.546(4), b= 8.072(2), c= 19.854(5)A, β= 102.73(2)°, respectively. The tetranuclear [Ag4I8]4– anion is centrosymmetric and can be described in terms of two edge-sharing silver(I)–iodide tetrahedra, each linked via a common edge to an approximately planar silver(I)–iodide triangle. In the latter the silver(I) atom is displaced 0.054(1)(1) and 0.026(1)A(2) from the plane through the three iodide ligands. The Ag–I distances associated with the three-co-ordinated centre are 2.727(2), 2.763(2), and 2.765(2)A(1), and 2.721 (1), 2.757(1), and 2.766(1)A(2), while those involving the four-co-ordinated centre range from 2.842(2) to 2.991 (2)(1) and 2.846(1) to 2.973(1)A(2). The Ag ⋯ Ag separations are 3.171 (2) and 3.256(2), and 3.198(1) and 3.306(2)A in (1) and (2), respectively. The [Ag3I4]– polymers in [PPh4][Ag3I4](3) and [PPh4][Ag3I4](4) consist of triple chains of edge-sharing Ag–I tetrahedra, Ag–I distances ranging from 2.796(2)–2.972(3)(3) and 2.798(4)–2.966(4)A(4). The anions in [AsPh4]2[Ag2Cl4] and [AsPh4]2[Ag2Br4] are centrosymmetric, approximately planar entities in which silver(I) is displaced 0.004(1)(5) and 0.048(1)A(6) from the ligand plane, and the Ag ⋯ Ag separations are 3.659(2)(5) and 3.549(2)A(6). In [Ag2Cl4]2–, the bridging Ag–Cl distances differ considerably from one another, i.e. 2.446(2) and 2.809(2)A, the terminal Ag–Cl bond being 2.359(2)A. In [Ag2Br4]2–, there is less discrepancy between bridging distances: 2.614(1) and 2.741 (1)A; Ag–Br(terminal) is 2.481 (1)A.

Copper(I) alkoxides: preparation and structural characterisation of triphenylmethoxocopper(I) and of an octanuclear form of t-butoxocopper(I)

Two copper(I) alkoxides, the novel compound triphenylmethoxocopper(I) and an octanuclear form of t-butoxocopper(I), have been prepared from mesitylcopper(I) and the relevant alcohol. [Cu-4(OCPh3)(4)]. 2C(6)H(5)CH(3) (1) and [Cu-8((OBu)-Bu-t)(8)] (2) have been characterised by means of crystal structure determination. Compound 1 contains two crystallographically independent triphenylmethoxocopper(I) molecules, each with a planar Cu-4 core. The Cu4O4 unit is butterfly-shaped with the oxygen ligands situated alternately approximately 0.4 Angstrom above and below the plane through the copper atoms, and the triphenylmethyl groups spread out over both sides of the Cu4O4 core. The copper(I) centres are two-coordinated with distances of 1.83(1)-1.86(1) Angstrom and O-Cu-O angles of 169.4(5)degrees. [Cu-8((OBu)-Bu-t)(8)] (2) can be described as being composed of two approximately planar Cu4O4 cores, each with the t-butyl groups bent away in the same direction from the Cu4O4 plane. These units are related to one another by a centre of symmetry and with weak Cu-O interactions of 2.493(5) and 2.536(5) Angstrom, involving four of the eight coppers, thus yielding an octanuclear Cu8O8 core. These four copper(I) centres thus attain T-shaped three-coordination by oxygen, whereas the remaining four are approximately linearly coordinated. The short Cu-O bond lengths in 2 range from 1.844(5) to 1.888(5) Angstrom.

A comparative study of 1,7-octadiene and 1,7-octadiyne complexes of copper(I) chloride: preparation and molecular structures

Abstract Polymeric complexes, [Cu 2 Cl 2 (C 8 H 14 )] ( 1 ) and [Cu 2 Cl 2 (C 8 H 10 )] ( 2 ), prepared by direct reaction between copper(I) chloride and 1,7-octadiene and 1,7-octadiyne, respectively, have been between characterized by crystal-structure determinations and IR spectroscopy. In both structures the organic ligands act as bridges between copper(I). In 1 , there are two cystallographically independent copper(I) centres, one of which is three coordinated by CC and two chloride ligands, the olefin being twisted 4° out of the coordination plane. The other copper(I) centre is (3 + 1) coordinated and exhibits a larger olefin twist (10° from the trigonal plane). The CuC bond lengths lie in the range 2.036(4)-2.100(4) A, and the CC bond lengths are 1.353(6) and 1.356(6) A. In 2 , copper(I) is trigonally pyramidally coordinated, with the CC linkage in the trigonal plane; CuC = 2.029(6) and 2.053(6) A and CC = 1.196(9) A. The v (CC) and v (CC) frequencies are lowered by ca. 98 cm −1 and 135 cm −1 , respectively, on complexation. In contrast to v (C sp 2 H), which remains virtually unchanged, v (C sp H) is lowered by 117 cm −1 , indicating activation of the acetylenic CH bond; this feature is, however, not paralleled by a significant lengthening of the CH bond or bending back of the acetylenic hydrogen atom in the crystal structure.