The d6-Co(III)-species [tripodCo-(ortho-(X.)(Y)C6H4)]+ (X, Y = O, S, tripod = CH3C(CH2PPh2)3) 1 are reversibly reduced to the neutral d7-Co(II)-compounds [tripodCo-(ortho-(X)(Y)C6H4)] (X, Y = O, S) 2. Both species show fivefold coordination of cobalt with coordination polyhedra in between the limits of the square pyramid and the trigonal bipyramid respectively. The low-spin d7-species 2 give clearly resolved ESR-spectra revealing the coexistence of two geometric isomers above -8 0 °C, with only one isomer persistent at temperatures around 100 K. As an analogous d5-system [benzyltripodFe-(ortho-(S)(S)C()H4)]+ 3 (benzyltripod = C6H5CH2C(CH2PPh2)3) has been obtained from [öe«z_y/rr//70ö?Fe(NCCH3)3]2+ and C6H6S2. Alternatively complexes of this type, e.g. [m poJFe-(orf/io-(S)(S)C6H4)]+ 4, may be prepared from Fe(H 2Ö )6(BF4)2/rnpod/C6H6S2 when the reaction mixture is activated by acidification with HBF4. The geometry of the ds-species 3 and 4 is close to a trigonal bipyramid.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A virtually planar water tetramer in which the water molecules are virtually tetrahedrally coordinated could be realized in the solid in a three-dimensional network of [Tc4(CO)12-(mu3-OH)4.4H2O]. The network could be produced by cocrystallization of the new cubane-like cluster [Tc(CO)3-(mu3-OH)]4 and water as a complementary component. The amphiphilic behavior of cluster and water results in a highly ordered three-dimensional network. The complementary components, the water tetramer and the cubic cluster, independently of one another form two interpenetrating tetragonal lattice networks held together exclusively by hydrogen bonds.

A virtually planar water tetramer in which the water molecules are virtually tetrahedrally coordinated could be realized in the solid in a three-dimensional network of [Tc4(CO)12-(μ3−OH)4·4H2O]. The network could be produced by cocrystallization of the new cubane-like cluster [Tc(CO)3-(μ3-OH)]4 and water as a complementary component. The amphiphilic behavior of cluster and water results in a highly ordered three-dimensional network. The complementary components, the water tetramer and the cubic cluster, independently of one another form two interpenetrating tetragonal lattice networks held together exclusively by hydrogen bonds.

A set of 112 993 structures was analysed for a specific type of packing: Molecular structures for which the centres of molecules form layers of centred hexagons exceed a percentage of 30%. This result has been obtained by a newly developed algorithm, allowing the extraction of these structures automatically and showing correlations between molecular shape and the type of packing.

The reaction behaviour Of P(C6H4CH2NMe2-2)(3) (1) towards different copper(II) and copper(l) salts of the type CuX2 (2a: X = BF4, 2b: X = PF6, 2c: X = ClO4, 2d: X = NO3, 2e: X = Cl, 2f. X = Br, 13: X = O2CMe) and CuX (5a: X ClO4, 5b: X = NO3, 5c: X = Cl, 5d: X = Br) is discussed. Depending on X, the transition metal complexes [P(C6H4CH2NMe2-2)(3)Cu]X-2 (3a: X = BF4, 3b: X = PF6), {[P(C6H4CH2NMe2-2)(3)]CuX}X (4: X = ClO4, 11a: X = Cl, 11b: X = Br, 14: X = O2CMe), {[P(C6H4CH2NMe2-2)(3)]Cu}ClO4 (6), [P(C6H4CH2NMe2-2)(3)]CuX (7a: X = Cl, 7b: X = Br, 10: X = ONP2), [P(C6H4CH2NMe2-2)(2)(C6H4CH2-NMe2H+NO3--2)]CuONO2 (9) and [P(C6H4CH2NMe2-2)(3)]CuCl}-CuCl2 (12) are accessible. While in 3a, 3b and 6 the phosphane I preferentially acts as tetrapodale ligand, in all other species only the phosphorus atom and two of the three C6H4CH2NMe2 side-arms are datively-bound to the appropriate copper ion. In solution a dynamic behaviour of the latter species is observed. Due to the coordination ability of X in 3a, 3b and 6 non-coordinating anions X- are present. However, in 4 one of the two perchlorate ions forms a dative oxygen-copper bond and the second perchlorate ion acts as counter ion to {[P(C6H4CH2NMe2-2)(3)]CuOClO3}(+). In 7, 9 and 10 the fragments X (X = Cl, Br, ONO2) form a a-bond with the copper(l) ion. The acetate moiety in 14 acts as chelating ligand as it could be shown by IR-spectroscopic studies. All newly synthesised cationic and neutral copper(l) and copper(II) complexes are representing stable species. Redox processes are involved in the formation of 9 and 12 by reacting I with 2. The solid-state structures of 4, 6, 9 and 10 are reported. In the latter complexes the copper(II) (4) or copper(l) ion (6, 9, 10) possesses the coordination number 4. This is achieved by the formation of a phosphorus- and two nitrogen-copper- (4, 9, 10) or three (6) nitrogen-copper dative bonds and a coordinating (4) or a-binding (9, 10) ligand X. In 6 all three nitrogen and the phosphorus atoms are coordinatively bound to copper, while X acts as non-coordinating counter-ion. Based on this, the respective copper ion occupies a distorted tetrahedral coordination sphere. While in 4 and 10 a free, neutral Me2NCH2 side-arm is present, which rapidly exchanges in solution with the coordinatively-bound Me2NCH2 fragments, this unit is protonated in 10. NO3- acts as counter ion to the CH2NMe2H+ moiety. In all structural characterized complexes 6-membered boat-like CuPNC3 cycles are present.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The stereochemical flexibility of six-membered chelate cycles containing phosphorus donor groups has not yet been analysed in detail. With a number of compounds of the type [(kappa-PR2CH2CH(OH)CH2-K-PR'(2))Rh(eta(4)-COD)]+PF6- at hand, and since the solid state structures and the catalytic properties of these compounds are known, an ideal opportunity to study this topic was available. After assigning all of the important H-1, C-13, and P-31 NMR spectroscopic resonances by a combination of one- and two-dimensional NMR spectroscopic methods quantitative interpretation of the 2D NOESY/EXSY spectra was achieved for four compounds [PR2 = PMes(2); PR'(2) = PPh2 (1), DBP (2), PEt2 (3), P(o-anisyl)(2) (4)]. It is found that the conformations that these compounds adopt in solution are similar to the ones observed for them in the solid state. The conformational ensemble in solution comprises lambda twist and delta twist forms;) and 6 isomers are clearly differentiated by quantitative NOE-based structure analysis (distance geometry). Since the sense of chirality of the ligand is known, an absolute assignment of these conformations is possible. The equilibrium constants at 298 K for the delta reversible arrow lambda, isomerisation of compounds 1-4 are not very different from one another, with reaction enthalpies ranging from -8 to -2 kJ mol(-1) and the reaction entropies in the range of -10 to 8 J K-1 mol(-1). The activation barriers are again similar for 1-4 and lie at DeltaH(not equal) = 64 kJ mol(-1). It is observed that the mesityl entities at the PMes(2) donor groups behave as coupled rotors with two rotational pathways open to them during the 6 reversible arrow delta interconversion while they are rotationally fixed in the lambda and delta conformations themselves. Comparing the above results with the enantioselective discrimination found for the same compounds in hydrogenation experiments it becomes clear that there is no direct correlation between the preference of one twist form over the other in the precatalyst and its chiral performance. (C) Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.

Eleven solid state structures of eight compounds 1-8 of the type [{kappa-PAr2CH2CH(OH)CH2-x-PAr'(2))Rh-(eta(4)-COD)]+PF6- are used as a basis for deriving a force field model for this class of compound by Genetic Algorithms. By a complete search in the conformational space of [{kappa-PMes(2)CH(2-) CH(OH)CH2-K-PPh2)Rh-(eta(4)-COD)]+PF6- (1) it is shown that the model is not only capable of reproducing the structures but as well capable to predict the stability of individual conformers and the conformational reaction pathways in full agreement with experimental observations. The model predicts that the k twist conformation is the most stable conformation of 1. The delta twist conformation is calculated 3.1 kJ(.)mol(-1) above this minimum. The experimental value is 3.4 kJ.mol-1. The model predicts that there are two mechanistic pathways for the kJ(.)mol(-1) isomerization process. Both of them are characterised by a strictly coupled rotation of the mesityl groups of the PMes(2) entity of 1. These two pathways differ only in the sense of this rotation. The activation enthalpy for the lambda reversible arrow delta isomerization process as a whole is calculated as DeltaH(#) = 69.1 kJ-mol(-1). The experimental value is DeltaH(#) = 64.4 kJ(.)mol(-1). It is concluded therefore that the novel type of approach as described leads to models of very high predictive power. (C) Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.

The title compounds 3-5 are accessible by treatment of P(C6H4CH2NMe2)3(1) with CuX (2a: X = Cl, 2b: X = Br, 2c: X = I) in the ratio of 1:1 or 1:2 in very good yields. Reaction of 1 with equimolar amounts of 2a affords the copper(I) chloride [P(C6H4CH2NMe2)3]CuCl (3). With a further equivalent of 2a homobimetallic [P(C6H4CH2NMe2)3]Cu2Cl2 (4) is formed, which also can be synthesized by the reaction of 1 with two equivalents of 2a. Complex 3 reacts with CuX (X = Br, I)to afford [P(C6H4CH2NMe2)3]Cu2ClX (5a: X = Br; 5b: X = I) in which mixed halides are present. The newly synthesized complexes 3-5 were characterized by elemental analyses, by their IR-, 1H-, 13C{1H}- and 31P{1H}-NMR spectra as well as by mass spectrometrical studies. The solid-state structures of complexes 3 and 4 are reported. Mononuclear 3 crystallizes in the monoclinic space group P21/c with the cell parameters a = 14.285(2), b = 10.853(2), c = 17.425(2) A , β = 103.310(10)?, V = 2628.9(7) A 3 and Z = 4 with 4053 observed unique reflections; R1 = 0.0314. The crystal structure of 3 consists of monomeric molecules with planar coordinated copper(I) centres (CuClNP). Homobimetallic 4 crystallizes in the monoclinic space group P21/n with a = 23.905(4), b = 10.874(3), c = 25.314(5), β = 99.130(10)?, V = 6497(2) /Aring; 3 and Z = 4 with 9021 observed unique reflections; R1 = 0.0480. In 4 one of two copper(I) centres possesses a distorted trigonal-pyramidal environment, while the other one is almost square-pyramidal coordinated. The Cu2Cl2 segment resembles to a building block which is set up by a contact ion pair consisting of Cu+ and [CuCl2]- , respectively.

The reaction of [Ti](CCPh)2 (1) {[Ti]=(η5-C5H4SiMe3)2Ti} with equimolar amounts of CuBr, Ni(PPh3)3 or Pd(PPh3)4 produces the heterobimetallic early–late transition metal complexes of general type {[Ti](CCPh)2}MX [2: MX=CuBr, 3: MX=Ni(PPh3), 4: MX=Pd(PPh3)} in which the respective transition metal atoms are linked by σ,π-bound alkynyl ligands. The solid-state structure of 1 and 4 is reported. In heterobimetallic 4 the Pd(0) centre possesses a trigonal–planar environment caused by the two η2-coordinated Me3SiCC ligands and the datively bonded PPh3 group. The PPh3 moiety is thereby located out of the best Ti(CCSi)2Pd plane. Comparative cyclic voltammetric studies on complexes 1–4 as well as {[Ti](CCPh)2}Ni(CO), for comparison, are presented. These studies reveal a strong influence of the η2-coordinated low-valent transition metal complex fragments MX on the reduction behaviour of the Ti(IV) centre.

nThe preparation of numerous donor-functionalised acetylides with Ti(IV) and/or Group II transition metals is described. The reaction of [Ti]Cl-2 (1) {[Ti] = (eta (5)-C5H4SiMe3)(2)Ti} with two equivalents of LiC=CR1 [2a: R-1 = CMe=CH2; 2b: R-1 = C6H4C=N-4; 2c: R-1 = CH2NMe2; 2d: R = C5H4N-4] affords the bis(alkynyl)titanocenes [Ti](C=CR1)(2) [3a: R-1 = CMe=CH2; 3b: R-1 = C6H4C=N-4; 3c: R-1 = CH2NMe2] in good yields. While by treatment of 1 with 2d in a 1:2 molar ratio only non-characterisable products are formed, the use of [Ti](Cl)(CH2SiMe3) (4) produces [Ti](CH2SiMe3)(C=CC5H4N-4) (5) in excellent yields. Monomeric, donor-functionalised copper(I) acetylides of general type {[Ti](C=CR1)(2)}CuC=CR3 [R-1 = Bu-t, 7a: R-3 = C=CCH2CH3; 7b: R-3 = CMe=CH2; 7c: R-3=C6H4C=N-4: R-1 = SiMe3, 7d: R-3 = CMe=CH2; 7e: R-3=C6H4C=N-4] are accessible by (i) the reaction of {[Ti](C=(CBu)-Bu-t)(2)}CuSC6H4CH2NMe2-2 (6) with equimolar amounts of 2a-2c or (ii) treatment of the monomeric copper(I) methyl {[Ti](C=CR1)(2)}CuCH3 (8a: R-1 = SiMe3, 8b: R-1 = Bu-t) with HC=CR3 [9a: R-3 = C=CCH2CH3, 9b: R-3 = CMe=CH2, 9c: R-3 = C6H4C=N-4] in a 1:1 molar ratio. The reaction chemistry of these complexes towards selected transition metal compounds is described. The bis(alkynyl)titanocenes 3a-3c produce with MLn {10a: MLn = CuCl; 10b: MLn = CuI; 10c: MLn = [Cu(CH3C=N)(4)][PF6]; 10d: MLn = AgBF4; 10e: MLn = Ni(CO)(4)} the heterobimetallic tweezer complexes {[Ti](C=CR1)(2)}ML [R-1 = CMe=CH2; 11a: ML = CuCl; R-1 = C6H4C=N-4; 11b: ML = CuCl; 11c: ML = CuI; 11d: ML = Ni(CO); R-1 = CH2NMe2; 11e: ML = CuPF6; 11f: ML = AgBF4]. In complexes 11a-11f an early and a late transition metal centre [e.g. Ni(0)] are linked via the corresponding (RC)-C-1=C ligands of the organometallic pi -tweezer complexes. For complexes lie and 11f a dynamic behaviour is observed in solution. The solid state structures of 3c and 7a are reported. Both compounds crystallise in the triclinic space group P (1) over bar. They exhibit features that are characteristic for this class of complexes: (i) a tetrahedral environment around the Ti(IV) of 3c and 7a, (ii) a lengthening of the C=C triple bonds upon eta (2)-coordination to the transition metal complex fragment CuC=CC=CC2H5, (iii) a trans-deformation of the Ti-C=C-Bu-t unit, and (iv) a reduction of the bite angle C-C=C-Ti-C-C=C for 7a. (C) 2001 Elsevier Science B.V. All rights reserved.

Improved syntheses of the known clusters [{(OC)5Cr}6Ge6]2− (1) and [{(OC)5Cr}6Sn6]2− (4) are reported. The new synthetic procedures also allow for the preparation of the molybdenum and tungsten derivatives [{(OC)5M}6Ge6]2− (M = Mo: 2; M = W: 3) and [{(OC)5M}6Sn6]2− (M = Mo: 5; M = W: 6). Compounds 1−6 were obtained as crystalline [Ph4P] salts, whose structures were determined for the whole series 1−6 by single-crystal X-ray analyses. All six [Ph4P] salts crystallise in tetragonal space groups, with the site group symmetries of the cluster core ranging from C4h to D4h. The average octahedral symmetry of the cluster core in solution is evident from 119Sn NMR spectroscopic data. Reversible one-electron oxidation of the dianions is suggested by cyclovoltammograms, while reduction is irreversible throughout. Electronic transitions which could be due to the cluster core were not found in the experimentally accessible energy range above 300 nm (below 4 eV). These findings indicate a high intrinsic stability of the precise electron clusters [Ge6]2− and [Sn6]2−.

Na-2[M-2(CO)(10)] and GeCl4 react to give the compounds [(CO)(5)MGeCl3](-), 1a - 1c (M = Cr, Mo, W). From M(CO)(5) . THF and GeI2 in the presence of I- compounds [(CO)(5)MGeI3](-), 2a - 2c (M = Cr, Mo, W) are obtained. Compounds 2a and 2c react with alkoholates or thiolates to produce the cage compounds [{(CO)(5)Cr}(6)Ge-6(mu(2)-OH)(2)(mu(3)-O)(6)](2-), 3, [{(CO)(5)Cr}(6)Ge-6-(mu(2)-OEt)(2)(mu(2)-O)(4)(mu(3)-O)(2)](2-), 4, and [{(CO)(5)W}(6)Ge-6(OR)(2)(mu(2)-O)(2)(mu(3)-O)(4)](2-), 5. A structural pattern common to all these compounds is an idealised octahedral arrangement of six germanium atoms. Each of these six germanium atoms binds to an M(CO)(5) protective group. The germanium atoms are integrated in the core of the cage compounds by mu(3)-O, mu(2)-O and mu(2)-OH bridges. The co-ordination number of germanium is generally four, with one bond radiating to the external M(CO)(5) building block. In compounds 3 and 4 the remaining three germanium bonds radiate to the bridging groups within the cage. Compounds 5 contain two germanium centres which are linked to the cage by only two bonds and with the two remaining bonds to the external M(CO)(5) entity and to a terminal OR or SR group. Syntheses and structures of compounds 1 - 5 are described.

Treatment of the tetrapodal phosphane P(C6H4CH2NMe2-2)(3) (1) with equimolar amounts of the silver(I) halides AgX (2a: X = Cl, 2b: X = Br) produces in tetrahydrofuran at 25 degreesC the monomeric silver(I) complexes [P(C6H4CH2NMe2-2)(3)]AgX With planar coordination at the Ag atoms (3 a: X = Cl, 3b: X = Br) in excellent yields.From complex 3b a single X-ray crystal structure analysis was carried out. Mononuclear 3b crystallizes in the monoclinic space group P2(1)/c with the cell parameters a = 14.504(6) b = 11.034(3), c = 17.604(5) Angstrom, beta = 102.86(4)degrees; V = 2746.6(16) Angstrom (3); Z = 4; 2953 observed unique reflections, R-1 = 0.0805.Complex 3b consists of monomeric sub-units with a planar T-shaped arrangement formed by the atoms Ag1, N1, P1 as well as Br1, whereby the P1-Ag1-Br1 array is almost linear orientated.

The anion of 2,4-dicyano glutaconic acid diethyl ester, [NCC(COOEt)CHC(COOEt)CN](1(-)), as an alpha, omega -dinitrile with a three atom spacer is a highly variable ligand capable of binding in a monodentate eta (1)-fashion, in a bidentate chelate fashion, and as a mu (2)-bridging entity. TripodFe(1)(2), 2, [tripod = CH3C(CH2PPh2)(3)] contains one chelating ligand 1(-) and one terminally coordinated ligand 1(-.) Variable temperature NMR spectroscopy shows, that, while the structure is static at 193 K, dynamic exchange of the donor functions of chelating and terminally bonded ligands occurs at higher temperature. TripodFe(1)(2), 2, is obtained from a 1:1:2 mixture of tripod, Fe(II)(aq) (BF4)(2), and Na1 . 2H(2)O. With a stoichiometry 1:1:1 of these ingredients and an additional half equivalent of sodium cyanide, the dinuclear compound [tripodFe{mu -NCC(COOEt)CHC(COOEt)CN}(2){mu -CN}Fetripod]BF4, 3BF(4), is obtained. The structure of 3(+) shows a helical arrangement of the ligands 1(-) around the Fe . . . Fe axis which is a consequence of the incomensurability of the bridging ligands 1(-) and mu -CN. The two iron centers in 3BF(4) differ by their coordination to the carbon or to the nitrogen terminus of the bridging cyano group. This difference is reflected by the NMR spectra, Mossbauer spectra and cyclovoltammograms.

The starlike anion [{(CO)5Cr}3Pb]2− (1) with its trigonal-planar coordination at the central metal Pb and its short Pb−Cr bonds (273 pm; left-hand structure) is an organometallic equivalent of CO32−. The conjugated Pb-pπ–Cr-dπ bonding system in 1 corresponds to the conjungated pπ–pπ bonding system of the carbonate ion. The unsaturated character of 1 is revealed in the formation of the PMe3 adduct [{(CO)5Cr}3PbP(CH3)3]2− (2) (d(Cr−Pb)=282 pm; right-hand structure).

The triphos ligand CH3C(CH2PPh2)(3) reacts with Co(BF4)(2) (aq) or Fe(BF4)(2) (aq) in the presence of nitriles RCN to produce the pentacoordinate [triphosCo(NCR)(2)](BF4)(2) (1) or the hexacoordinate [triphosFe(NCR)(3)](BF4)(2) (2). With alpha,omega-dinitriles NC-X-CN dinuclear compounds [triphosFe(NC-X CN)(3)Fetriphos](BF4)(4) (X = (CH2)(3) (3a) X = O-C6H4 (3b) are formed. The compound [triphosFe((CH3)(2)C=C(CN)(2))(3)Fetriphos] (3c) is obtained from FeCl2 by addition of the triphos ligand, the dinitrile and NaPF6. All compounds are characterised by the usual analytical techniques including X-ray analyses. It is observed that the quadruply positively charged compounds 3 tend to associate the respective anions in pockets formed by the three segments of the Fe(NC-X-CN)(3)Fe bridging units.

Mesitylcopper reacts with flavonol (flaH) in the presence of 1,3-bis(2-pyridylimino)isoindoline (indH) to yield the diamagnetic complex CuI(fla)(indH), which on reaction with molecular oxygen undergoes oxidative splitting of the C2-C3 bond of the pyranone ring of the flavonolate ligand to give CuI(indH)(O-bs) (O-bs = O-benzoylsalicylate) (orthorhombic, P1, a = 8.048(7) A, b = 8.969(9) A, c = 19.240(2) A, alpha = 85.69 degrees, beta = 80.24(7) degrees, gamma = 77.87(7) degrees, V = 1337(2) A3, Z = 2) and carbon monoxide. The reaction of [CuI(CH3CN)4]ClO4, flaH, and indH with dioxygen at room temperature affords the paramagnetic complex [CuII(fla)(indH)]ClO4 (mu = 2.10 mu B), and after elimination of HClO4, CuII(fla)(ind) (orthorhombic, Pbca, a = 8.888(2) A, b = 19.169(7) A, c = 33.614(10) A, alpha = beta = gamma = 90 degrees, V = 5727(3) A3, Z = 8) with mu = 1.86 mu B is formed. The latter undergoes cleavage of the pyranone ring on oxygenation at 80 degrees C to give CuII(ind)(O-bs) (mu = 1.87 mu B, nu(CO) = 1742 cm-1, and nu(CO2) = 1581, 1387 cm-1) and carbon monoxide. CuII(fla)(ind) and [CuII(fla)(indH)]ClO4 serve as good catalysts for the oxygenation of flavonol to O-benzoylsalicyclic acid.