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51.
Heroux KJ Woodin KS Tranchemontagne DJ Widger PC Southwick E Wong EH Weisman GR Tomellini SA Wadas TJ Anderson CJ Kassel S Golen JA Rheingold AL 《Dalton transactions (Cambridge, England : 2003)》2007,(21):2150-2162
A cross-bridged cyclam ligand bearing two N-carboxymethyl pendant arms (1) has been found to form a copper(II) complex that exhibits significantly improved biological behavior in recent research towards (64)Cu-based radiopharmaceuticals. Both the kinetic inertness and resistance to reduction of Cu-1 are believed to be relevant to its enhanced performance. To explore the influence of pendant arm length on these properties, new cross-bridged cyclam and cyclen ligands with longer N-carboxyethyl pendant arms, 2 and 4, and their respective copper(II) complexes have been synthesized. Both mono- as well as di-O-protonated forms of Cu-2 have also been isolated and structurally characterized. The spectral and structural properties of Cu-2 and Cu-4, their kinetic inertness in 5 M HCl, and electrochemical behavior have been obtained and compared to those of their N-carboxymethyl-armed homologs, Cu-1 and Cu-3. Only the cyclam-based Cu-1 and Cu-2 showed unusually high kinetic inertness towards acid decomplexation. While both of these complexes also exhibited quasi-reversible Cu(II)/Cu(I) reductions, Cu-2 is easier to reduce by a substantial margin of +400 mV, bringing it within the realm of physiological reductants. Similarly, of the cyclen-based complexes, Cu-4 is also easier to reduce than Cu-3 though both reductions are irreversible. Biodistribution studies of (64)Cu-labeled 2 and 4 were performed in Sprague Dawley rats. Despite comparable acid inertness to their shorter-armed congeners, both longer-armed ligand complexes have poorer bio-clearance properties. This inferior in vivo behavior may be a consequence of their higher reduction potentials. 相似文献
52.
Liu L Zakharov LN Golen JA Rheingold AL Watson WH Hanna TA 《Inorganic chemistry》2006,45(10):4247-4260
We report a series of calix[4]arene Mo(VI) dioxo complexes M2RC4MoO2 (M = alkali metal, R = H or Bu(t)) that were fully characterized by NMR, X-ray, IR, UV/vis, and elemental analysis. Molybdocalix[4]arene structures can be controlled via lower rim deprotonation, groups at para positions of calix[4]arene, and alkali metal counterions. Mono deprotonation at the lower rim leads to calix[4]arene Mo(VI) monooxo complexes RC4MoO (R = H, Bu(t), or allyl), and full deprotonation gives rise to calix[4]arene Mo(VI) dioxo complexes. Structural studies indicate that HC4 Mo(VI) dioxo complexes easily form polymeric structures via cation-pi interaction and coordination between different calixarene units. However, Bu(t)C4 Mo(VI) dioxo complexes tend to form dimers or tetramers due to steric hindrance of the tert-butyl groups at para positions in calixarene. The structures of the reduced side products A and C were determined by X-ray diffraction studies. The mechanism of RC4MoO formation from the reaction of calixarene monoanions with MoO2Cl2 appears to include the addition of a calixarene -OH group across a Mo=O bond. 相似文献
53.
Childress MV Millar D Alam TM Kreisel KA Yap GP Zakharov LN Golen JA Rheingold AL Doerrer LH 《Inorganic chemistry》2006,45(10):3864-3877
Two thallium aryloxide compounds TlOC6F5 (TlOAr(F)) and bis-3,5-TlOC6H3(CF3)2 (TlOAr') have been recrystallized from THF and crystallographically characterized in different isomeric forms. The latter compound forms a solvated tetrameric cubane, [TlOAr']4.THF, 1. The TlOAr(F) compound crystallized with a similar stoichiometry, [TlOAr(F)]4.2 THF, 2, but contains a [Tl2(mu2-OAr(F))4] unit that includes a thallophilic interaction at a distance of 3.5943(15) angstroms. Solution 205Tl and 203Tl NMR studies of 1 and 2 support the retention of a cubane structure for 1 in solution and suggest a similar structure for 2 with coupled thallium centers down to -90 degrees C. Fluorescence spectroscopy data for both compounds 1 and 2 in THF are consistent with LMCT. DFT calculations of 1, 2, and three models of the [Tl2(mu2-OAr(F))4] unit show a bonding overlap of the bridged thallium atoms in 2 and are also used to describe the bonding in 1. The structures of two heterobimetallic compounds, Tl2Cu(OAr(F))4, 4, and Tl2Cu(OAr')4, 5, with the [Tl2(mu2-OAr(F))4] structural motif and thallophilic contacts of 3.86(6) and 3.564(1) angstroms, respectively, are described. The crystal structures of the unsolvated of TlOAr(F), 2b, solvated heterobimetallic derivative Tl2Cu(OAr')4.2THF, 5b, and the monomeric (18-crown-6)TlOAr(F), 3, and 205Tl NMR spectra of TlOC6H5, 6, are also reported for comparison purposes. 相似文献
54.
Samson O. Owalude Adedibu C. Tella Ezekiel O. Odebunmi Uche B. Eke James E. Golen Arnold L. Rheingold 《Journal of Coordination Chemistry》2017,70(7):1260-1269
New ruthenium(II) complexes containing labile nitrile ligands have been prepared by treatment of either the polymer [{RuCl2(COD)}x] (COD = cycloocta-1,5-diene) (1) or its derivative [RuCl2(COD)(NCCH3)2]·NCCH3 (2) with the appropriate nitrile ligands in refluxing acetonitrile under argon. A new route to synthesis of trans-dichlorotetrakis(diphenylphosphine)ruthenium(II) (7) was also reported. A redetermination of the structure of 7 was undertaken and X-ray crystallographic data revealed that the complex crystallizes in the triclinic space group P-1 with unit cell dimensions a = 12.7016(9) Å, b = 13.0847(10) Å, c = 14.1498(10) Å, α = 101.46(3)°, V = 2080.6(3) Å3, Z = 2 and R = 0.0309. Its polymorph 7′ was also obtained. The crystal structure of 4 was also determined. This complex crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 27.0510(3) Å, b = 11.0984(13) Å, c = 13.0450(16) Å, α = 90°, V = 3886.5(8) Å3, Z = 8 and R = 0.0282. 相似文献
55.
Hydrogen‐Bonding Pincer Complexes with Two Protic N‐Heterocyclic Carbenes from Direct Metalation of a 1,8‐Bis(imidazol‐1‐yl)carbazole by Platinum,Palladium, and Nickel
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David C. Marelius Evan H. Darrow Dr. Curtis E. Moore Prof. James A. Golen Prof. Arnold L. Rheingold Prof. Douglas B. Grotjahn 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):10988-10992
Pincer protic N‐heterocyclic carbene (PNHC) complexes were synthesized by direct metalation, the formation of a metal carbon bond from an unfunctionalized C?H bond in a single synthetic step. Significantly, direct metalation succeeded even for a first‐row metal, nickel. The chloride complexes were isolated and then converted to the acetate, triflate, or in the platinum case, a hydride analogue. Crystal structures and 1H, 13C, and 15N NMR data, as well as IR spectra, document the effects of intramolecular hydrogen bonding and the planar but flexible pincer framework. Anti‐Markovnikov addition of O?H bonds to alkynes, including catalyzed alkyne hydration, were demonstrated on the Pt triflate analog. 相似文献
56.
U. Ibotomba Singh R. K. Bhubon Singh M. J. Borah J. P. Jasinski J. A. Golen 《Journal of Structural Chemistry》2013,54(1):116-122
A new monoclinic Cu(II) salt complex (C6H6N2) 2 + [Cu(2,6-dipico)2]2?·6H2O, (2,6-dipico=pyridine-2,6-dicarboxylic acid) is synthesized and characterised by CHN analyses, IR, UV-Vis, magnetic susceptibility measurements, and single crystal X-ray crystallography. The structure contains two pyridine-2,6-dicarboxylate species as tridentate ligands with protonated aniline acting as a counter cation and six uncoordinated water molecules. The complex crystallizes in the monoclinic space group C2/c with unit cell parameters a = 20.9393(4) Å, b = 7.94330(10) Å, c = 19.9093(4) Å, V(Å3) = 2932.32(9), Z = 4. Crystal packing is stabilized by N-H…O, O-H…O intermolecular hydrogen bonds and weak π…π interactions. The water molecules are trapped by a cooperative association of coordination interactions forming water clusters as well as by a hydrogen bond to the Cu (II) complex. 相似文献
57.
This paper obtains solitons as well as other solutions to a few nonlinear evolution equations that appear in various areas of mathematical physics. The two analytical integrators that are applied to extract solutions are tan–cot method and functional variable approaches. The soliton solutions can be used in the further study of shallow water waves in (1+1) as well as (2+1) dimensions. 相似文献
58.
Mehrdad Pourayoubi Atekeh Tarahhomi Arnold L. Rheingold James A. Golen 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(10):998-1002
In N,N,N′,N′‐tetraethyl‐N′′‐(4‐fluorobenzoyl)phosphoric triamide, C15H25FN3O2P, (I), and N‐(2,6‐difluorobenzoyl)‐N′,N′′‐bis(4‐methylpiperidin‐1‐yl)phosphoric triamide, C19H28F2N3O2P, (II), the C—N—C angle at each tertiary N atom is significantly smaller than the two P—N—C angles. For the other new structure, N,N′‐dicyclohexyl‐N′′‐(2‐fluorobenzoyl)‐N,N′‐dimethylphosphoric triamide, C21H33FN3O2P, (III), one C—N—C angle [117.08 (12)°] has a greater value than the related P—N—C angle [115.59 (9)°] at the same N atom. Furthermore, for most of the analogous structures with a [C(=O)NH]P(=O)[N(C)(C)]2 skeleton deposited in the Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B 58 , 380–388], the C—N—C angle is significantly smaller than the two P—N—C angles; exceptions were found for four structures with the N‐methylcyclohexylamide substituent, similar to (III), one structure with the seven‐membered cyclic amide azepan‐1‐yl substituent and one structure with an N‐methylbenzylamide substituent. The asymmetric units of (I), (II) and (III) contain one molecule, and in the crystal structures, adjacent molecules are linked via pairs of N—H...O=P hydrogen bonds to form dimers. 相似文献
59.
Mitchell A. Pet Russell P. Hughes James A. Golen 《Journal of organometallic chemistry》2009,694(14):2279-5343
Syntheses of the known ferrocenylmethylphosphines FcCH2PH2 (2, Fc = (η5-C5H4)Fe(η5-C5H5)), (FcCH2)2PH (3), and (FcCH2)3P (4) have been reinvestigated. The reaction of [FcCH2NMe3][I] with P(CH2OH)3, generated from [P(CH2OH)4][Cl] and KOH, gave a mixture of the major product (FcCH2)P(CH2OH)2 (1) and over-alkylated (FcCH2)2P(CH2OH) (9). Treatment of pure 9 with Na2S2O5 gave the secondary phosphine 3; slow addition of Na2S2O5 to 1 gave 2 in improved yield. Reaction of 1 with [FcCH2NMe3][I], followed by treatment with NEt3, gave the tertiary phosphine (FcCH2)3P (4), along with the known phosphonium salt [(FcCH2)4P][I] (5), which could be prepared in higher yield by adjusting the stoichiometry. Phosphine 4 oxidized slowly in air to yield (FcCH2)3P(O) (12), was protonated by HBF4(OMe2) to give [(FcCH2)3PH][BF4] (13), and reacted with Pt(COD)Cl2 or PtCl2 to yield a mixture of cis- and trans-Pt(P(CH2Fc)3)2Cl2 (14). Silylation of 2 with n-BuLi/Me3SiCl gave FcCH2P(SiMe3)2 (10); treatment of 1 with Me3SiCl/Et3N gave FcCH2P(CH2OSiMe3)2 (11). The phosphine-borane adducts FcCH2PH2(BH3) (6), (FcCH2)2PH(BH3) (7), (FcCH2)3P(BH3) (8) and (FcCH2)P(CH2OSiMe3)2(BH3) (15) were prepared from the corresponding phosphines and BH3(SMe2). The phosphines 2, 3, and 4, phosphonium salts 5 and 13, phosphine oxide 12, Pt complex trans-14, and phosphine-boranes 6, 7 and 8 were structurally characterized by X-ray crystallography. The solid cone angle of (FcCH2)3P, 139°, in Pt complex 14 showed that 4 was bulkier than PPh3, but less sterically demanding than P(t-Bu)3. The structural changes observed on quaternization of P (shorter P-C bonds and larger angles at P), along with results from NMR and IR spectroscopy and DFT calculations, were consistent with the expected rehybridization at phosphorus. Related observations for analogous methylphosphines suggest that methyl and ferrocenylmethyl phosphorus substituents have similar properties. 相似文献