A rare uranium(III) alkyl complex, Tp*2U(CH2Ph) (2) (Tp* = hydrotris(3,5-dimethylpyrazolyl)borate), was synthesized by salt metathesis from Tp*2UI (1) and KCH2Ph fully characterized using 1H NMR, infrared, electronic absorption spectroscopies as well X-ray crystallography. This complex has a uranium−carbon distance of 2.57(2) Å, which is comparable to other uranium alkyls reported. Treating this compound with either carbon dioxide or disulfide results in insertion into the bond generate...

Uranium compounds supported by redox-active α-diimine ligands, which have methyl groups on the ligand backbone and bulky mesityl substituents nitrogen atoms {MesDABMe = [ArN═C(Me)C(Me)═NAr], where Ar 2,4,6-trimethylphenyl (Mes)}, are reported. The addition of 2 equiv MesDABMe, 3 KC8, 1 UI3(THF)4 produced bis(ligand) species (MesDABMe)2U(THF) (1). metallocene derivative, Cp2U(MesDABMe) (2), was generated an equimolar ratio MesDABMe KC8 to Cp3U. bond lengths in molecular structure both confirm...

Grafting (ArO)2W(═O)(═CHtBu) (ArO = 2,6-mesitylphenoxide) on partially dehydroxylated silica forms mostly [(≡SiO)W(═O)(═CHtBu)(OAr)] along with minor amounts of [(≡SiO)W(═O)(CH2tBu)(OAr)2] (20%), both fully characterized by elemental analysis and IR NMR spectroscopies. The well-defined oxo alkylidene surface complex [(≡SiO)W(═O)(═CHtBu)OAr] is among the most active heterogeneous metathesis catalysts reported to date in self-metathesis cis-4-nonene ethyl oleate, sharp contrast classical based...

We report an examination of the ring-opening metathesis polymerization (ROMP) endo-dicyclopentadiene (DCPD) by 10 well-defined molybdenum-based and 16 tungsten-based alkylidene initiators. Five MAP (monoaryloxide pyrrolide) initiators with general formula W(X)(CHCMe2Ph)(Me2Pyr)(OAr) (X = arylimido, alkylimido, or oxo; Me2Pyr =2,5-dimethylpyrrolide; OAr aryloxide) were found to yield >98% cis, syndiotactic poly(DCPD); they are W(N-t-Bu)(CHCMe3)(pyr)(OHMT) (2, OHMT O-2,6-(2,4,6-Me3C6H2)2C6H3,...

Abstract The reaction of [W(O)(CHCMe 2 Ph)(dAdPO) ], containing bulky 2,6‐diadamantyl aryloxide ligands, with partially dehydroxylated silica selectively yields a well‐defined silica‐supported alkylidene complex, [(SiO)W(O)(CHCMe Ph)(dAdPO)]. This fully characterized material is very active and stable alkene metathesis catalyst, thus allowing loadings as low 50 ppm in the internal alkenes. Ph)(dAdPO)] also efficiently catalyzes homocoupling terminal alkenes, turnover numbers exceeding...

Trivalent Cp*(2)U(2,2'-bpy) (2) (Cp* = C(5)Me(5), 2,2'-bpy 2,2'-bipyridine), which has a monoanionic bipyridine, was treated with p-tolualdehyde (a), furfuraldehyde (b), acetone (c), and benzophenone (d). Reduction of the C[double bond, length as m-dash]O bond followed by radical coupling bipyridine forms U(iv) derivatives [Cp*(2)U(2,2'-bpy)(OCRR')] (3a-d).

We have employed 2,3-dicarbomethoxynorbornadiene (DCMNBD) as a monomer to explore new tungsten oxo alkylidene complexes initiators for stereoregular ROMP (ring-opening metathesis polymerization). The include MAP (monoaryloxide pyrrolide) with the general formula W(O)(CHCMe2Ph)(Me2Pyr)(OAr) (Me2Pyr = 2,5-dimethylpyrrolide, OAr an aryloxide) and W(O)(CHCMe2Ph)(OR)2 (OR aryloxide or OC(CF3)3), PPh2Me CH3CN adducts thereof. found that yield cis,syndiotactic-poly(DCMNBD) consequence of...

We report here the polymerization of several 7-isopropylidene-2,3-disubstituted norbornadienes, 7-oxa-2,3-dicarboalkoxynorbornadienes, and 11-oxa-benzonorbornadienes with a single tungsten oxo alkylidene catalyst, W(O)(CH-t-Bu)(OHMT)(Me2Pyr) (OHMT = 2,6-dimesitylphenoxide; Me2Pyr 2,5-dimethylpyrrolide) to give cis, stereoregular polymers. The tacticities menthyl ester derivatives two polymers were determined for types. For poly(7-isopropylidene-2,3-dicarbomenthoxynorbornadiene) structure was...

A family of rare uranium(III) alkyl complexes, Tp*2UR (R = CH2SiMe3 (3-CH2SiMe3), CH3 (4-CH3), (CH2)3CH3 (5-(CH2)3CH3); Tp* hydrotris(3,5-dimethylpyrazolyl)borate), was synthesized by salt metathesis with alkylsodium reagents and Tp*2UI (2). All compounds were fully characterized using 1H NMR, infrared, electronic absorption spectroscopies. Compounds 3-CH2SiMe3 4-CH3 structurally X-ray crystallography have U–C bond distances 2.601(9) 2.54(3) Å, respectively.

We have found that coordination of B(C6F5)3 to an oxo ligand in tungsten alkylidene bis(aryloxide) complexes, where the aryloxide is O-2,6-(mesityl)2C6H3 (HMTO) or 2,6-diadamantyl-4-methylphenoxide (dAdPO), accelerates formation metallacyclobutane complexes from alkylidenes as well rearrangement complexes. In contrast, a tungstacyclopentane complex, W(O)(C4H8)(OHMT)2, relatively stable toward presence B(C6F5)3. A careful balance steric factors allows single isomer...

The synthesis of a rare uranium(III) bis(benzyl), Tp*U(CH2Ph)2(THF) (2), was achieved by salt metathesis Tp*UI2(THF)2 with 2 equiv KCH2Ph at low temperature. This characterized 1H NMR, infrared, and electronic absorption spectroscopy as well X-ray crystallography. Addition benzophenone to forms the uranium(IV) radical coupling product Tp*U(CH2Ph)2(OC(Ph)2CH2Ph) (3), whereas N3Mes produces imido derivative Tp*U(NMes)(CH2Ph)(THF) (4). Adding further 1 tetravalent 4 results in U–C insertion...

Abstract Reported herein are the preparation and characterization of trans ‐[Cr(cyclam)(X‐ gem ‐DEE) 2 ]OTf compounds ( ‐DEE = σ‐ geminal ‐diethynylethene, OTf trifluoromethanesulfonate) 1 , which first examples 3d metal complexes containing ligands. All reported were characterized by visible, emission, infrared spectroscopy, electrochemistry (CV DPV), high‐resolution mass spectrometry, compound was further studied single‐crystal X‐ray diffraction. Both photophyiscal data structural indicate...

Alkynyl complexes of the type [M(cyclam)(CCR)(2)]OTf (where cyclam = 1,4,8,11-tetraazacyclotetradecane; M Rh(III) or Cr(III); and R phenyl, 4-methylphenyl, 4-trifluoromethylphenyl, 4-fluorophenyl, 1-naphthalenyl, 9-phenanthrenyl, cyclohexyl) were prepared in 49% to 93% yield using a one-pot synthesis involving addition 2 equiv RCCH 4 BuLi appropriate [M(cyclam)(OTf)(2)]OTf complex THF. The cis trans isomers alkynyl separated solubility differences, stereochemistry was characterized infrared...

We previously communicated the preparation and characterization of two trans-[Fe(cyclam)(C≡CR)2]OTf compounds, 2b 2c (where cyclam = 1,4,8,11-tetraazacyclotetradecane, R −SiiPr3 (2b) or −Ph (2c), OTf trifluoromethanesulfonate), which were first examples Fe(III) bis-alkynyl complexes. In this work, series has been expanded to include −H (2a), −C2SiMe3 (2d), −C4SiMe3 (2e), −Fc (2f), prepared from reaction between cis/trans-[Fe(cyclam)(OTf)2]OTf (1) LiC≡CR (NaC≡CH for 2a). Compounds 2a–2f...

The electronic structures of two uranium compounds supported by redox-active α-diimine ligands, ((Mes)DAB(Me))(2)U(THF) (1) and Cp(2)U((Mes)DAB(Me)) (2) ((Mes)DAB(Me) = [ArN═C(Me)C(Me)═NAr]; Ar 2,4,6-trimethylphenyl (Mes)), have been investigated using both density functional theory multiconfigurational self-consistent field methods. Results from these studies established that centers are tetravalent, the ligands reduced electrons, ground states molecules triplets. Energetically low-lying...

Imido alkylidene complexes of Mo and W oxo that contain thiophenoxide ligands the type S-2,3,5,6-Ph4C6H (STPP) S-2,6-(mesityl)2C6H3 (SHMT = S-hexamethylterphenyl) have been prepared in order to compare their metathesis activity with analogous phenoxide complexes. All thiolate were significantly slower (up ∼10× slower) for homocoupling 1-octene or polymerization 2,3-dicarbomethoxynorbornene, none them was Z-selective. The rates could be attributed greater σ-donating ability a versus...

Reported in this Article are the preparation and characterization of a series new Ru2(II,III) compounds bearing one cross-conjugated σ-geminal-diethynylethene ligand (gem-DEE), namely, Ru2(Xap)4(Y-gem-DEE) (Xap = N,N'-anilinopyridinate (ap) or 2-(3,5-dimethoxy)anilinopyridinate (DiMeOap), Y Si(i)Pr3 (1) H (2)) [Ru2(ap)4]2(μ-gem-DEE) (3). Compounds 1-3 were characterized by spectroscopic voltammetric techniques as well single crystal X-ray diffraction study 2a. The structural data 2a...

Reported in this contribution are the preparation and characterization of a series Ru(2)(DMBA)(4) (DMBA = N,N'-dimethylbenzamidinate) bis(alkynyl) compounds, trans-Ru(2)(DMBA)(4)(X-gem-DEE)(2) [gem-DEE σ-geminal-diethynylethene; X H (1), Si(i)Pr(3) (2), Fc (3); 4-C(6)H(4)NO(2) (4), 4-C(6)H(4)NMe(2) (5)]. Compounds 1-5 were characterized by spectroscopic voltammetric techniques as well single-crystal X-ray diffraction studies 2 3. Both structural data compounds 3 spectroscopic/voltammetric...

Gas-phase modification of carboxylic acid functionalities is performed via ion/ion reactions with carbodiimide reagents [N-cyclohexyl-N′-(2-morpholinoethyl)carbodiimide (CMC) and [3-(3-Ethylcarbodiimide-1-yl)propyl]trimethylaminium (ECPT)]. covalent chemistry requires the formation a long-lived complex. In this instance, complex stabilized by an electrostatic interaction between fixed charge quaternary ammonium group reagent cation analyte dianion. Subsequent activation results in...

A substituted TREN has been prepared in which the aryl groups (ArylNHCH2CH2)3N are at 3- and 5-positions with a total of six OCH2(CH2)nCH═CH2 (n = 1, 2, 3). Molybdenum nitride complexes, [(ArylNCH2CH2)3N]Mo(N), have isolated as adducts that contain B(C6F5)3 bound to nitride. Two these [(ArylNCH2CH2)3N]Mo(NB(C6F5)3) complexes 1 3) were crystallographically characterized. After removal borane from PMe3, ring-closing olefin metathesis (RCM) was employed join rings OCH2(CH2)nCH═CH(CH2)nCH2O...

Reported herein are the preparation and characterization of trans-[Fe(cyclam)(X-gem-DEE)2]OTf (where cyclam = 1,4,8,11-tetraazacyclotetradecane, gem-DEE σ-geminal-diethynylethene, OTf trifluoromethanesulfonate) compounds 2a, 2b, 2c (X −Ph (2a), −SiiPr3 (2b), −Fc (2c)), which first examples redox-active 3d metal complexes containing ligands. These were prepared from reaction between cis/trans-[Fe(cyclam)(OTf)2]OTf (1) X-gem-DEE-Li. Compounds 2a–2c characterized by spectroscopic/voltammetric...

Abstract The reaction of [W(O)(CHCMe 2 Ph)(dAdPO) ], containing bulky 2,6‐diadamantyl aryloxide ligands, with partially dehydroxylated silica selectively yields a well‐defined silica‐supported alkylidene complex, [(SiO)W(O)(CHCMe Ph)(dAdPO)]. This fully characterized material is very active and stable alkene metathesis catalyst, thus allowing loadings as low 50 ppm in the internal alkenes. Ph)(dAdPO)] also efficiently catalyzes homocoupling terminal alkenes, turnover numbers exceeding...

New trans-[Fe(cyclam)(C≡CR)(2)]OTf compounds 2a/2b [cyclam = 1,4,8,11-tetraazacyclotetradecane, R Si(i)Pr(3) (a) or Ph (b), and OTf trifluoromethanesulfonate] were prepared from the reaction between trans-[Fe(cyclam)(OTf)(2)]OTf (1) LiC≡CR. The trans arrangement of acetylide ligands in 2 was established X-ray diffraction study 2a, density functional theory calculations revealed significant dπ-π(C≡C) interactions.

Injectable sustained release dosage forms have emerged as desirable therapeutic routes for patients that require life-long treatments. The prevalence of drug molecules with low aqueous solubility and bioavailability has added momentum toward the development suspension-based long-acting parenteral (LAP) formulations; previously undesirable physicochemical properties Biopharmaceutics Classification System (BCS) Class II/IV compounds are best suited extended applications. Effective in vitro...