Tris(pentafluorosulfanyl)amine, N(SF5)(3), and the bis(pentafluorosulfanyl)aminyl radical, center dot N(SF5)(2), have been synthesized and characterized by gas electron diffraction, single crystal XRD, NMR, EPR, Raman, and UV-vis spectroscopy, and by their thermal decompositions. The amine possesses a planar molecular structure of D-3 symmetry with an unusually long N-S bond of 1.829(6) angstrom. The long N-S bonds are in accordance with the small Arrhenius activation barrier for the decay into center dot N(SF5)(2) and center dot SF5 radicals of 6.9 kcal mol(-1), and its half-life at room temperature is only 50 min. The aminyl radical possesses C-2 symmetry with N-S = 1.692(4) angstrom and S-N-S = 135.1(5)degrees, and its structure is similar to that of FN(SF5)(2). This radical is much more stable than the amine (half-life at room temperature is 130 min). Dimerization and formation of the corresponding hydrazine, (SF5)(2)NN(SF5)(2), was not observed, nor was the nitrene:NSF5 or its isomer FN=SF4. (C) 2016 Elsevier B.V. All rights reserved.

Primary and secondary phosphine complexes are convenient precursors of terminal phosphido-metal compounds by deprotonation. Recent work has shown that the chiral tertiary phosphido-metal group Fe —PMePh can be generated stereospecifically by deprotonation of a resolved secondary phosphine complex at —90 °C, and, furthermore, that it can be alkylated with retention of configuration and com­ plete stereoselectivity at that temperature [1 , 2 ]. Here we report the synthesis of (/?*,R *)-(± C5H 5){l,2-C 6H4(PMePh)2}Fe(PCl3)]Cl-2M eCN [3] and its crystal structure. The enantiomers of this compound are potential precursors of optically active phosphine complexes containing the Fe+<—PH 3 group, which we intend to investigate as sources of optically active tertiary phosphine complexes (Fe+<— P R 'R 2R ) by asymmetric synthesis. To our knowledge, this is the first structurally authenticated iron-phosphorus trichloride complex. The title complex was isolated by recrystallization from acetonitrile of the product obtained from the reaction between (/?*,/?*)-(±)-[(//;'-O H :s){ 1,2CftH4(PMePh)2}Fe(NCMe)]PF6 [4] and excess PC13 in boiling tetrahydrofuran (20 h under reflux). The

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 molecular structure of [Me2Al(mu-OPh)](2) has been determined. The phenoxide ring is parallel to the Al2O2 ring rather than the energetically favored perpendicular configuration determined by ab initio calculations. Ab initio calculations successfully predict the structures of sterically demanding analogs. The adoption of the parallel configuration allows for an estimation of the magnitude of crystal packing forces. A discussion of the parameters controlling the structures of dialkylaluminum phenoxides is presented. Crystal data: group Pbca, a = 12.127(2), b = 8.491(2), c = 17.299(4) angstrom, V = 1781.3(6) angstrom(3), Z = 4, R = 0.0695, wR(2) = 0.1390.

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 reaction of the methylidyne-bridged cluster HRu3(CO)(10)(mu-COMe) (1) with the diphosphine ligand 4,5-bis( diphenylphosphino)-4-cyclopenten-1,3-dione ( bpcd) and Me3NO furnishes HRu3(CO)(8) (mu-COMe)( bpcd) ( 2) and HRu3(CO)(8)(Ph2PH)[mu-PPh2C=CC(O)CH2C(O)] ( 3) as the major and minor products, respectively. The H-1 and P-31 NMR data indicate that the bpcd ligand in 2 is chelated to one of the ruthenium atoms that is bridged by the hydride and methylidyne ligands. Thermolysis of 2 is accompanied by P-Ph bond cleavage and elimination of benzene to yield Ru-3(CO)(7)(mu(3)-COMe) [mu-P(Ph)C=C(PPh2)C(O)CH2C(O)] ( 4). Compound 4 consists of a triangular ruthenium core that is face-capped by mu(3)-COMe methylidyne and mu-P(Ph)C=C(PPh2) C( O) CH2C( O) phosphido ligands. The kinetics for the conversion of 2 -> 4 have been measured in toluene solvent over the temperature range 320-343 K, and based on the observed activation parameters and the inhibitory effect of added CO on the reaction, a rate-limiting step involving a dissociative loss of CO is supported. Heating 4 in the presence of H-2 afforded the phosphinidene-capped cluster H3Ru3(CO)(7)(mu(3)-PPh)[mu-C=C(PPh2)C(O)CH2C(O)] ( 5). Crystallographic analysis of 5 has confirmed the loss of the methylidyne moiety and the cleavage of the phosphido PhP-C( dione) bond, and the presence of three edge-bridging hydrides is supported by H-1 NMR spectroscopy. The reaction of 4 with added PPh3 and PMe3 has been investigated; the uptake of a single phosphine ligand occurs regiospecifically at one of the phosphido-bound ruthenium centers to give Ru-3(CO)(6)L(mu(3)-COMe)[mu-P(Ph)C=C( PPh2)C( O) CH2C( O)] (PPh3, 6; PMe3, 7). Compound 6 contains 48e- and exhibits a structural motif similar to that found in 4. Compound 7 readily adds a second PMe3 ligand to yield the bis-substituted cluster Ru-3(CO)(6)( PMe3)(2)(mu(2)- COMe)[mu-P( Ph) C=C( PPh2) C( O) CH2C( O)] ( 8). The solid-state structure of 8 confirms the loss of two ruthenium-ruthenium bonds and the conversion of the original face-capping mu(3)-COMe ligand to a mu(2)-COMe moiety that tethers two non-bonding ruthenium centers. The two PMe3 ligands in 8 coordinate to the same ruthenium center, and the 9e- P( Ph) C=C( PPh2) C( O) CH2C( O) ligand binds all three ruthenium atoms through the phosphine, phosphido, alkene, and carbonyl moieties. Near-UV irradiation of 8 leads to loss of CO and polyhedral contraction of the triruthenium frame to yield the 48e- cluster Ru-3(CO)(5)(PMe3)(2)(mu(3)-COMe)[mu-P( Ph)C= C(PPh2) C( O) CH2C( O)] ( 9). (C) 2008 Elsevier B.V. All rights reserved.

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 ruthenium cluster Ru-3(CO)(12) reacts with the diphosphine ligand 3,4-bis(diphenylphosphino)5-methoxy-2(5H)-furanone (bmf) in refluxing toluene to furnish the donor-acceptor compound Ru-2(CO)(2)( bmf) as a 1:1 mixture of diastereomers. Photolysis of Ru2( CO) 2( bmf) using 366 nm light leads to the oxidative cleavage of a P-C bond and formation of the phosphido-bridged complex Ru-2(CO)(6)[mu-C=C(PPh2)C(O)OCH(OMe)](mu-PPh2). The regioselective Ph2P-C(furanone ring) bond activation attendant upon optical excitation is traced to the phosphine group that was beta to the furanone carbonyl group, as established by X-ray analysis of one of the diastereomers of Ru-2(CO)(6)[mu-C=C(PPh2)C(O)OCH(OMe)](mu-PPh2). Both diruthenium products have been fully characterized in solution by IR and NMR (H-1 and P-31) spectroscopies and elemental analyses. The observed regioselectivity associated with the P-C bond activation in Ru-2(CO)(2)( bmf) is discussed with respect to the chemistry of other bmf-substituted compounds prepared by our groups.

Me3NO activation of the methylidyne- bridged cluster HRu3(CO)(10)(mu-COMe) (1) in the presence of the unsaturated diphosphine ligand 2,3-bis(diphenylphosphino) maleic anhydride (bma) furnishes the bma- substituted cluster HRu3(CO)(8)(bma)(mu-COMe) (2) and the diphenylphosphine-substituted cluster HRu3(CO)(8)(Ph2PH)[mu- PPh2C = CC(O) OC(O)] (3) as the major and minor products, respectively. The H-1 and P-31 NMR data indicate that the bma ligand in cluster 2 is chelated to one of the ruthenium atoms that is bridged by the hydride and methylidyne ligands. Cluster 3 has been fully characterized in solution by IR and NMR spectroscopies, and the solid-state structure determined by X-ray crystallography. 3 crystallizes in the monoclinic space P2(1), a = 12.1467(7) angstrom, b = 19.284( 1) angstrom, c = 16.867(1) angstrom, beta = 109.639( 6)degrees, V = 3721.0( 4) angstrom(3), Z = 4, and d(calcd) = 1.774 g cm(-3); R = 0.0325, R-w = 0.0383 for 3518 reflections with I > 3 sigma(I). The X-ray data confirm that one of the P-C(maleic anhydride) bonds of the bma ligand has been cleaved and that cluster 3 contains Ph2PH and mu-PPh2C = CC(O)OC(O) ligands, the latter which functions as a face-Capping ligand to all three ruthenium atoms. Control experiments indicate that cluster 2 does not function as a precursor to cluster 3 under the employed reaction conditions.

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.

Interest in macrocyclic lanthanide complexes such as DOTA is driven largely through interest in their use as contrast agents for MRI. The lanthanide tetraamide derivatives of DOTA have shown considerable promise as PARACEST agents, taking advantage of the slow water exchange kinetics of this class of complex. We postulated that water exchange in these tetraamide complexes could be slowed even further by introducing a group to sterically encumber the space above the water coordination site, thereby hindering the departure and approach of water molecules to the complex. The ligand 8O(2)-bridged DOTAM was synthesized in a 34% yield from cyclen. It was found that the lanthanide complexes of this ligand did not possess a water molecule in the inner coordination sphere of the bound lanthanide. The crystal structure of the ytterbium complex revealed that distortions to the coordination sphere were induced by the steric constraints imposed on the complex by the bridging unit. The extent of the distortion was found to increase with increasing ionic radius of the lanthanide ion, eventually resulting in a complete loss of symmetry in the complex. Because this ligand system is bicyclic, the conformation of each ring in the system is constrained by that of the other; in consequence, inclusion of the bridging unit in the complexes means only a twisted square, antiprismatic coordination geometry is observed for lanthanide complexes of 8O(2)-bridged DOTAM.

Two series of isomeric, redox-responsive azacrown ethers based on ortho- and para-phenylenediamine (Wurster's crowns) have been synthesized and their properties explored through 13C NMR spectroscopy, electrospray ionization mass spectrometry, cyclic voltammetry, and X-ray crystallography. These crowns display strong affinity for alkali metal cations while maintaining comparable selectivity profiles to the parent crown ethers from which they are derived. Like Wurster's reagent (N,N,N',N'-tetramethyl-p-phenylenediamine or para-TMPD), the para-Wurster's crowns undergo two reversible one-electron oxidations. The integrity of the alkali metal ion complexes is maintained in the neutral and singly oxidized ligand states but not after removal of two electrons. In contrast, the oxidation of ortho-Wurster's crowns is scan rate dependent, occurring at potentials substantially higher than their para counterparts, with their complexes oxidizing irreversibly. X-ray crystal structures of representative complexes show, in all cases, participation of the redox-active phenylenediamine subunits in complex formation via direct bonding to the guest cation.

Treatment of the zwitterionic hydrocarbyl compound Co2(CO)4[μ-PhCC(H)PPh2CC(PPh2)C(O)OC(O)] (1) with PMe3 leads to CO insertion and formation of the acyl species Co2(CO)3(PMe3)[μ-PhC(CO)C(H)PPh2CC(PPh2)C(O)OC(O)] (2). Compound 2 is unstable at elevated temperatures and loses CO to produce the PMe3-substituted compound Co2(CO)3(PMe3)[μ-PhCC(H)PPh2CC(PPh2)C(O)OC(O)] (3) as the major product. Compounds 2 and 3 have been isolated and characterized in solution by IR and NMR (13C and 31P) spectroscopies and in the solid state by X-ray diffraction analyses.

Controlled thermolysis of the mixed-metal clusters RCCo2NiCp(CO)(6) (R = H, Ph) with the chiral diphosphine ligand 3,4-bis(diphenylphosphino)-5-methoxy-2(5H)-furanone (bmf) leads to CO substitution and formation of the corresponding bmf-bridged clusters RCCo2NiCp(CO)(4) (bmf) (R = H, Ph). These clusters exist in solution as a non-interconverting mixture of diastereomers, as determined by NMR spectroscopy. Whereas the benzylidyne-capped cluster PhCCo2NiCp(CO)(4)(bmf) decomposes in 1,2-dichloroethane (DCE) during prolonged heating at 83 degrees C, thermolysis of HCCo2NiCp(CO)(4)(bmf) affords the new phosphido-bridged cluster Co2NiCp-(CO)(4)[mu(2),eta(2),eta(1)-C(H)C=C(PPh2)C(O)OCH(OMe)](mu-PPh2) under the same conditions. This latter cluster has been isolated and characterized in solution by IR and NMR spectroscopies and the solid-state structure determined by X-ray diffraction analysis. The structural highlights for Co2NiCp(CO)(4)[mu(2),eta(2),eta(1)-C(H)C=C(PPh2)C(O)OCH(OMe)](mu-PPh2) include the regioselective cleavage of the P-C(furanone ring) bond, coupled with polyhedral opening of the CON core and attack on the CpNi center by the other phosphine moiety of the bmf ligand. The diastereoselectivity accompanying the formation of cluster Co2NiCp(CO)(4)[mu(2),eta(2),eta(1)-C(H)C=C(PPh2)C(O)OCH(OMe)](mu-PPh2) is discussed relative to steric effects within the cluster polyhedron. (c) 2005 Elsevier B.V. All rights reserved.

Thermolysis of the mixed-metal cluster PhCCo2MoCp(CO)(8) (1) with the diphosphine ligand 2,3-bis(diphenylphosphino)maleic anhydride (bma) in CH2Cl2 leads to the sequential formation of the phosphido-bridged cluster Co2MoCp(CO)(5)[mu(2),eta(2), eta(1)-C(Ph)C=C(PPh2)C(O)OC(O)](mu-PPh2) (3) and the bis(phosphido)-bridged cluster Co2MoCp(CO)(4)[eta(3), eta(1), eta(1)-C(Ph)C=CC(O)O-C(O)](mu-PPh2)(2) (4). 3 and 4 have been isolated and characterized in solution by IR and NMR (H-1, C-13, and P-31) spectroscopies, and the solid-state structures have been established by X-ray diffraction analyses. Both clusters contain 48e- and exhibit triangular Co2Mo cores. The structure of 3 reveals the presence of a phosphido moiety that bridges the Co-Co vector and a six-electron mu(2), eta(2), eta(1)-C(Ph)C=C(PPh2)C(O)OC(O) ligand that caps one of the Co2Mo faces. The X-ray structure of 4 confirms that the five-electron eta(3), eta(1), eta(1)-C(Ph)C=CC(O)OC(O) ligand is sigma-bound to the two cobalt centers in an eta(1) fashion and pi-coordinated to the molybdenum center through a traditional eta(3)-allylic interaction. The reaction between PhCCo2MoCp(CO)(8) and the chiral diphosphine ligand 3,4-bis(diphenylphosphino)-5-methoxy-2(5H)-furanone (bmf) proceeds similarly, furnishing the phosphido-bridged cluster Co2MoCp(CO)(5) [mu(2), eta(2),eta(1)-C(Ph)C=C(PPh2)C(O)OCH(OMe)](mu-PPh2) (6), followed by conversion to Co2MoCp(CO)(4)[eta(3), eta(1), eta(1)-C(Ph)C=CC(O)O-CH(OMe)](mu-PPh2)(2) (7). The identities of clusters 6 and 7 have been ascertained by solution spectroscopic methods and X-ray crystallography. The overall molecular structure of cluster 6 is similar to that of cluster 3, except that the P-C(furanone ring) bond cleavage occurs with high regioselectivity and high diastereoselectivity. The cleavage of the remaining P-C(furanone ring) bond in cluster 6 gives rise to the bis(phosphido) -bridged cluster 7, whose structure is discussed relative to its bma-derived analogue 4. The diastereoselectivity that accompanies the formation of 6 and 7 is discussed relative to steric effects within the Co2Mo polyhedron. The cyclic voltammetric properties of cluster 3 have been examined, with three well-defined one-electron processes for the 0/+1, 0/-1, -1/-2 redox couples found. The composition of the HOMO and LUMO in 3 was established by extended Hockel MO calculations, with the data discussed relative to the parent tetrahedrane cluster 1. (c) 2006 Elsevier B.V. All rights reserved.