John E. Ellis

University of Minnesota Duluth, Duluth, Minnesota, United States

Are you John E. Ellis?

Claim your profile

Publications (82)259.89 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Reduction of VCl3(THF)3 (THF is tetrahydrofuran) and NbCl4(THF)2 by alkali metal pyrene radical anion salts in THF affords the paramagnetic sandwich complexes bis[(1,2,3,3a,10a,10b-η)-pyrene]vanadium(0), [V(C16H10)2], and bis[(1,2,3,3a,10a,10b-η)-pyrene]niobium(0), [Nb(C16H10)2]. Treatment of tris(naphthalene)titanate(2−) with pyrene provides the isoelectronic titanium species, isolated as an (18-crown-6)potassium salt, namely catena-poly[[(18-crown-6)potassium]-μ-[(1,2-η:1,2,3,3a,10a,10b-η)-pyrene]-titanate(−I)-μ-[(1,2,3,3a,10a,10b-η:6,7-η)-pyrene]], {[K(C12H24O6)][Ti(C16H10)2]}n. The first two compounds have very similar packing, with neighboring molecules arranged orthogonally to one another, such that aromatic donor–acceptor interactions are likely responsible for the specific arrangement. The asymmetric unit contains a half-occupancy metal center η6-coordinated to one pyrene ligand, with the full M(pyrene)2 molecule generated by a crystallographic inversion center. In the titanium compound, the cations and anions are in alternating contact throughout the crystal structure, in one-dimensional chains along the [101] direction. As in the other two compounds, the asymmetric unit contains a half-occupancy Ti atom η6-coordinated to one pyrene ligand. Additionally, the asymmetric unit contains one half of an (18-crown-6)potassium cation, located on a crystallographic inversion center coincident with the K atom. The full formula units are generated by those inversion centers. In all three structures, the pyrene ligands are eclipsed and sandwich the metals in one of two inversion-related sites. These species are of interest as the first isolable homoleptic pyrene transition metal complexes to be described in the scientific literature.
    Acta Crystallographica Section C. 08/2014;
  • William W Brennessel, John E Ellis
    [Show abstract] [Hide abstract]
    ABSTRACT: Homoleptic 2,2'-bipyridine (bipy) metalates of iron and cobalt have been synthesized directly from the corresponding homoleptic anthracene metalates. In the iron structure, bis[([2.2.2]cryptand)potassium(I)] tris(2,2'-bipyridine)ferrate(-I) anthracene(-I), [K(C18H36N2O6)]2[Fe(C10H8N2)3](C14H10), the asymmetric unit contains one potassium complex cation in a general position, the Fe center and one and a half bipy ligands of the ferrate complex on a crystallographic twofold axis that includes the Fe atom, and one half of an anthracene radical anion whose other half is generated by a crystallographic inversion center. The cations and anions are well separated and the geometry about the Fe center is essentially octahedral. In the cobalt structure, ([2.2.2]cryptand)potassium(I) bis(2,2'-bipyridine)cobaltate(-I) anthracene hemisolvate tetrahydrofuran (THF) disolvate, [K(C18H36N2O6)][Co(C10H8N2)2]·0.5C14H10·2C4H8O, the asymmetric unit contains the cation, anion, and both cocrystallized THF solvent molecules in general positions, and one half of a cocrystallized anthracene molecule whose other half is generated by a crystallographic inversion center. The cation and anion are well separated and the ligand planes in the cobaltate anion are periplanar. Each anthracene molecule is midway between and is oriented perpendicular to a pair of symmetry-related bipy ligands such that aromatic donor-acceptor interactions may play a role in the packing arrangement. The lengths of the bonds that connect the bipy rings support the assertion that the ligands are bipy radical anions in the iron structure. However, in the case of cobalt, these lengths are between the known ranges for a bipy radical anion and a bipy dianion, and therefore no conclusion can be made from the crystallography alone. One cocrystallized THF solvent molecule in the cobalt structure was modeled as disordered over three positions with appropriate geometric and thermal restraints, which resulted in a refined component mass ratio of 0.412 (4):0.387 (3):0.201 (3).
    Acta crystallographica. Section C, Structural chemistry. 08/2014; 70(Pt 8):828-832.
  • Source
    William W Brennessel, John E Ellis
    [Show abstract] [Hide abstract]
    ABSTRACT: The title salt, [K(C18H36N2O6)][Co(CO)4], is an example of a classical carbonyl-metalate. The asymmetric unit contains one cation and one tetrahedral anion, both in general positions. Based on comparison of the four carbonyl C-O bond lengths and C-Co-C angles, the anion is unperturbed by the cation, which is normal for an alkali metal fully encased by a cryptand cage.
    Acta Crystallographica Section E Structure Reports Online 05/2014; 70(Pt 5):m180. · 0.35 Impact Factor
  • Source
    William W Brennessel, John E Ellis
    [Show abstract] [Hide abstract]
    ABSTRACT: The title salt, [K(C(12)H(24)O(6))][Fe(C(8)H(12))(C(10)H(8))], is the only known naphthalene complex containing iron in a formally negative oxidation state. Each (naphthalene)(1,5-cod)ferrate(-I) anion is in contact with one (18-crown-6)potassium cation via K⋯C contacts to the outer four carbon atoms of the naphthalene ligand (cod = 1,5-cyclo-octa-diene, 18-crown-6 = 1,4,7,10,13,16-hexa-oxacyclo-octa-deca-ne). When using the midpoints of the coordinating olefin bonds, the overall geometry of the coordination sphere around iron can be best described as distorted tetra-hedral. The naphthalene fold angle between the plane of the iron-coordinating butadiene unit and the plane containing the exo-benzene moiety is 19.2 (1)°.
    Acta Crystallographica Section E Structure Reports Online 10/2012; 68(Pt 10):m1230-1. · 0.35 Impact Factor
  • Source
    William W Brennessel, John E Ellis
    [Show abstract] [Hide abstract]
    ABSTRACT: The title salt, [K(C(18)H(36)N(2)O(6))][Co(C(2)H(4))(4)], is one of only two known homoleptic ethyl-enemetalates. The cation and anion are well separated, which gives an unperturbed tetra-hedral anion as is expected for a formally Co(-I)d(10) metal center. The considerable elongation of the C=C bonds of the ethyl-ene ligands [average 1.401 (6) Å], relative to that of free ethyl-ene (1.333 Å), is consistent with metal→π* back-bonding models. One arm of the 2.2.2-cryptand (4,7,13,16,21,24-hexa-oxa-1,10-diaza-bicyclo-[8.8.8]hexa-cosa-ne) complexant is disordered and was modeled over two positions with a refined occupancy ratio of 0.559 (2):0.441 (2). In the crystal, the cationic K(2.2.2-cryptand) units are linked via C-H⋯O hydrogen bonds, forming inversion dimers. There are no other significant inter-molecular inter-actions in the crystal structure.
    Acta Crystallographica Section E Structure Reports Online 10/2012; 68(Pt 10):m1257-8. · 0.35 Impact Factor
  • William W Brennessel, John E Ellis
    [Show abstract] [Hide abstract]
    ABSTRACT: Reductions of CoBr(2) or cobaltocene by 3 equiv of potassium anthracene radical anion in tetrahydrofuran (THF) afford 60-80% yields of bis(anthracene)cobaltate(1-) (1), of interest as a readily accessible and quite labile source of spin-paired atomic Co(-). Although the unsolvated potassium salt of 1 is thermally unstable at 20 °C, the [K(18-crown-6)(THF)(2)](+) salt of 1 functions as a useful storable crystalline reagent for Co(-) in several reactions. Previously known classic cobaltates, [CoL(4)](-), for L = 1/2 (1,3-butadiene) (2), PF(3) (3), and P(OiPr)(3) (5), were obtained directly from 1 and structurally characterized for the first time. Anion 3 is noteworthy because it appears to possess the shortest known Co-P distance, av = 2.012(4) Å. Although the naphthalene analogue of 1 is not yet available as a pure substance, low-temperature reductions of CoBr(2) or cobaltocene by naphthalene radical anion in the presence of 1,5-cyclooctadiene (COD) afford variable yields (80-90% from CoCp(2)) of (naphthalene)(COD)cobaltate(1-) (10). Ready displacement of naphthalene in 10 by L = 1,3-butadiene, 2,2'-bipyridine, and COD occurs to give good yields of the respective [Co(L)(COD)](-), all of which have been structurally characterized. Both ligands in 10 are displaced by tert-butylisocyanide to afford [Co(CNtBu)(4)](-) (16), the first isolable and structurally characterized homoleptic alkylisocyanometalate. The molecular structure of 16 shows unprecedented bending of the isocyanides, av C-N-C = 137(2)°, for homoleptic isocyanide complexes.
    Inorganic Chemistry 08/2012; 51(16):9076-94. · 4.59 Impact Factor
  • Source
    William W Brennessel, John E Ellis
    [Show abstract] [Hide abstract]
    ABSTRACT: The cation, anion, and solvent in the title compound, [K(C(18)H(36)N(2)O(6))][Co(C(8)H(12))(C(16)H(10))(2)]·0.5C(5)H(12), are well separated. The pentane solvent mol-ecules are found in channels along [100] and were modeled as disordered over crystallographic inversion centers. Using the mid-points of the coordinated olefins, the angle between the C(py)/C(py)-Co-C(py)/C(py) and the C(cod)/C(cod)-Co-C(cod)/C(cod) planes (py is pyrene and cod is cyclo-octa-diene) is 67.6 (2)°. Thus, the overall geometry of the coordination sphere around cobalt is best described as distorted tetra-hedral.
    Acta Crystallographica Section E Structure Reports Online 07/2012; 68(Pt 7):m1013-4. · 0.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The title compound, [Mo(C(10)H(8))(2)], was prepared from the naphthalene radical anion and MoCl(4)(thf)(2) (thf is tetra-hydro-furan). In the crystal, the mol-ecule is located on an inversion center. The Mo atom is equally disordered over two positions; the range of Mo-C distances is 2.2244 (19)-2.3400 (17) Å for both components of the disorder.
    Acta Crystallographica Section E Structure Reports Online 02/2012; 68(Pt 2):m220. · 0.35 Impact Factor
  • Victor J Sussman, John E Ellis
    [Show abstract] [Hide abstract]
    ABSTRACT: For the first time [N(PPh(3))(2)](+), or [PPN](+), has been shown to undergo an irreversible reaction with a transition metal complex under ambient conditions and affords a product containing a unique structural motif in which two phenyl groups on one PPh(3) substituent of [PPN](+) are ortho-metallated, while the third phenyl ring is hydrogenated to provide a tantalum bound 1,3-cyclohexadiene group.
    Chemical Communications 12/2008; · 6.38 Impact Factor
  • Angewandte Chemie International Edition 11/2008; 47(45):8692-5. · 11.34 Impact Factor
  • Victor J Sussman, John E Ellis
    Angewandte Chemie International Edition 02/2008; 47(3):484-9. · 11.34 Impact Factor
  • Victor J. Sussman, John E. Ellis
    Angewandte Chemie 01/2008; 120(3).
  • Jessica M. Allen, John E. Ellis
    [Show abstract] [Hide abstract]
    ABSTRACT: Oxidation of [CpTi(CO)4]− by I2, Ph3SnCl, and Me3SnCl in the presence of four equivalents of CNXyl, Xyl=2,6-dimethylphenyl, affords unprecedented titanium tetraisocyanide complexes, [CpTi(CNXyl)4E], E=I, SnPh3, SnMe3. These have been isolated and characterized by spectroscopic methods as well as single-crystal X-ray crystallography. A by-product of the iodine reaction was the Ti(III) complex, [CpTi(CNXyl)2I2], which was also characterized by X-ray crystallography.
    Journal of Organometallic Chemistry 01/2008; 693:1536-1542. · 2.00 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Oxidation of [Ti(CO)(6)](2-) by thiuram disulfides, (R(2)NCS(2))(2), affords the first isolable mononuclear six-coordinate titanium(0) carbonyls, [Ti(CO)(4)(S(2)CNR(2))](-), which have unusual trigonal prismatic geometries and chemical and spectral properties that are remarkably similar to those of the 18-electron and seven-coordinate anion [Ti(CO)(4)(eta(5)-C(5)H(5))](-).
    Chemical Communications 08/2007; · 6.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Treatment of [M(CO)(6)](-), M = Nb, Ta, with Ag(+), I(2) or NO(+) in the presence of CNXyl provided [M(CNXyl)(7)](+), M(CNXyl)(6)I, or cis-[M(CNXyl)(4)(NO)(2)](+), which are isocyanide analogues of the unknown carbonyl complexes [M(CO)(7)](+), M(CO)(6)I, or cis-[M(CO)(4)(NO)(2)](+), respectively. Reduction of M(CNXyl)(6)I by cesium graphite gave the respective Cs[M(CNXyl)(6)], which have been structurally characterized and represent the first isolable homoleptic isocyanidemetalates for second or third row transition metals. Nitrosylation of [Ta(CNXyl)(6)](-) affords a rare example of a mononitrosyl tantalum complex, Ta(CNXyl)(5)NO, which is an isocyanide analogue of the unknown Ta(CO)(5)NO. This study emphasizes, inter alia, the remarkable versatility of the CNXyl ligand compared to CO in stabilizing various electronic environments at heavier group 5 metal centers.
    Journal of the American Chemical Society 03/2007; 129(5):1141-50. · 10.68 Impact Factor
  • William W Brennessel, John E Ellis
    Angewandte Chemie International Edition 02/2007; 46(4):598-600. · 11.34 Impact Factor
  • Angewandte Chemie International Edition 02/2007; 46(32):6132-6. · 11.34 Impact Factor
  • Angewandte Chemie International Edition 12/2006; 45(43):7268-71. · 11.34 Impact Factor
  • John E Ellis
    [Show abstract] [Hide abstract]
    ABSTRACT: A brief history of substances containing s,p- and d-block metals in negative oxidation states is described. A classification of these species and discussions of formal oxidation state assignments for low-valent transition metals in complexes are included, along with comments on the innocent and noninnocent character of ligands in metalates. Syntheses of highly reduced carbonyl complexes formally containing transition metals in their lowest known oxidation states of III- and IV- are discussed. Atmospheric-pressure syntheses of early-transition-metal carbonyls involving alkali-metal polyarene-mediated reductions of non-carbonyl precursors have been developed. In the absence of carbon monoxide, these reactions afford homoleptic polyarenemetalates, including the initial species containing three aromatic hydrocarbons bound to one metal. In several instances, these metalates function as useful synthons for "naked" spin-paired atomic anions of transition metals.
    Inorganic Chemistry 05/2006; 45(8):3167-86. · 4.59 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The first tris(arene)niobium complex, [Nb(1-4-eta 4-anthracene)3]-, has been obtained by the sodium or potassium anthracene reduction of NbCl4(THF)2, structurally characterized by X-ray analysis and shown to undergo facile anthracene displacement reactions in the presence of excess CO, PF3, 1,3,5,7-cyclooctatetraene and P(OMe)3.
    Chemical Communications 11/2002; · 6.38 Impact Factor