A5047094325- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Organometallic Complex Synthesis and Catalysis
- Synthesis and characterization of novel inorganic/organometallic compounds
- Organophosphorus compounds synthesis
- Oxidative Organic Chemistry Reactions
- Crystallography and molecular interactions
- Catalytic Cross-Coupling Reactions
- Coordination Chemistry and Organometallics
- Synthesis and Catalytic Reactions
- Asymmetric Hydrogenation and Catalysis
- Organoboron and organosilicon chemistry
- Cyclopropane Reaction Mechanisms
- Radical Photochemical Reactions
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Metal complexes synthesis and properties
- Synthetic Organic Chemistry Methods
- Phosphorus compounds and reactions
- Catalytic C–H Functionalization Methods
- Magnetism in coordination complexes
- Fluorine in Organic Chemistry
- Porphyrin and Phthalocyanine Chemistry
- Synthesis and Reactivity of Sulfur-Containing Compounds
- Luminescence and Fluorescent Materials
- Asymmetric Synthesis and Catalysis
Case Western Reserve University
2014-2024
University of California, San Diego
2004-2021
Clemson University
2010-2013
University of Auckland
2010-2013
University of Toledo
1999-2011
Pennsylvania State University
2010
Cleveland State University
2009
Purdue University West Lafayette
2006-2007
Youngstown State University
2007
University of Miami
2006
Cyano-substituted oligo(p-phenylene vinylene) derivatives can display piezochromic fluorescence. This rare and desirable effect is achieved by balancing π–π aliphatic interactions in these molecules through the variation of electron density central ring length peripheral tails. leads to fluorophores which adopt different supramolecular structures as a result change their solid-state emission characteristics upon compression.
A new sterically encumbered bifunctional ligand has been developed, and its ability to provide simultaneous stabilization for two low-coordinate phosphorus centers allowed the synthesis of hybrid inorganic-organic conjugated materials. The phosphaalkene polymers have prepared from a diphospha-Wittig reagent are exclusively E-configured about P=C bonds. An unprecedented polymer having diphosphene (-P=P-) units in main chain is also reported. soluble were characterized by UV-visible...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCleavage of the Nitrous Oxide NN Bond by a Tris(amido)molybdenum(III) ComplexCatalina E. Laplaza, Aaron L. Odom, William M. Davis, Christopher C. Cummins, and John D. ProtasiewiczCite this: J. Am. Chem. Soc. 1995, 117, 17, 4999–5000Publication Date (Print):May 1, 1995Publication History Published online1 May 2002Published inissue 1 1995https://pubs.acs.org/doi/10.1021/ja00122a033https://doi.org/10.1021/ja00122a033research-articleACS...
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTADDITION / CORRECTIONThis article has been corrected. View the notice.A New Class of Iodonium Ylides Engineered as Soluble Primary Oxo and Nitrene SourcesDainius Macikenas, Ewa Skrzypczak-Jankun, John D. ProtasiewiczView Author Information Department Chemistry, Case Western Reserve University Cleveland, Ohio 44106-7078 Toledo Toledo, 43606-3390 Cite this: J. Am. Chem. Soc. 1999, 121, 30, 7164–7165Publication Date (Web):July 16,...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe 15 years of reductive coupling: what have we learned?Edmund M. Carnahan, John D. Protasiewicz, and Stephen J. LippardCite this: Acc. Chem. Res. 1993, 26, 3, 90–97Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published inissue 1 March 1993https://pubs.acs.org/doi/10.1021/ar00027a003https://doi.org/10.1021/ar00027a003research-articleACS PublicationsRequest reuse permissionsArticle...
Syntheses and characterizations are reported for dimolybdenum(II) compounds supported by the diarylformamidinate (ArNC(H)NAr(-)) ligand, where Ar is XC(6)H(4)(-), with X as p-OMe (1), H (2), m-OMe (3), p-Cl (4), m-Cl (5), m-CF(3) (6), p-COMe (7), p-CF(3) (8), or 3,4-Cl(2)C(6)H(3)(-) (9) 3,5-Cl(2)C(6)H(3)(-) (10). The (quasi)reversible oxidation potentials measured Mo(2)(5+)/Mo(2)(4+) couple were found to correlate Hammett constant (sigma(X)) of aryl substituents according following equation:...
ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionA New Class of Iodonium Ylides Engineered as Soluble Primary Oxo and Nitrene SourcesDainius Macikenas, Ewa Skrzypczak-Jankun, John D. Protasiewicz*Cite this: J. Am. Chem. Soc. 2011, 133, 11, 4151Publication Date (Web):February 25, 2011Publication History Published online25 February 2011Published inissue 23 March...
Phosphaalkenes (RP=CR 2 ) and diphosphenes (RP=PR) are main group analogues of alkenes (R C=CR ). Molecules featuring such multiply bonded phosphorus functionalities often display structural features chemical reactivities that mimic their purely organic counterparts, lending credence to the claim these compounds “carbon copies”. We have been expanding this analogy include oligomers polymers with extended conjugation directly involve P=C P=P units. Many materials, however, little or no...
Solubility is not the only advantage imparted on iodosylbenzene upon introduction of intramolecular I⋅⋅⋅O secondary bonds. These bonds also enabled first single-crystal structural determination such a species. The structure 2-(tBuSO2)C6H4IO (1) reveals how can compete with intermolecular which normally dominate properties iodosylbenzene. corresponding iodylbenzene shows similar features.
Phosphoranylidenephosphines DmpPPMe3 (1a, Dmp = 2,6-Mes2C6H3) and Mes*PPMe3 (1b, Mes* 2,4,6-But3C6H2) act as 'Phospha-Wittig' reagents with aldehydes providing phosphaalkenes [ArPC(H)R] in high yields.
A soluble (E)-poly(p-phenylenephosphaalkene) having sterically encumbering ligands has been prepared by a phospha-Wittig reaction. This material exhibits bathochromic shift with respect to E-PPV and representative model oligomers. We also report the first fluorescence study of poly(p-phenylenephosphaalkene) find that this fluorescence, though modest intensity relative similarly sized carbon-based analogues.
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTThree Different Fates for Phosphinidenes Generated by Photocleavage of Phospha-Wittig Reagents ArPPMe3Shashin Shah, M. Cather Simpson, Rhett C. Smith, and John D. ProtasiewiczView Author Information Department Chemistry Case Western Reserve University Cleveland, Ohio 44106-7708 Cite this: J. Am. Chem. Soc. 2001, 123, 28, 6925–6926Publication Date (Web):June 20, 2001Publication History Received6 March 2001Published online20 June inissue 1 July...
The phosphanylidene-sigma(4)-phosphorane reagents Me(3)P[double bond, length as m-dash]PAr (Ar = 2,4,6-(t)Bu(3)C(6)H(2) and 2,6-Mes(2)C(6)H(3)) are good delivery vehicles of the terminal phosphinidene moiety, PAr, to early-transition metals composed zirconium vanadium.
Abstract This microreview examines chemistry of phosphane adducts phosphinidenes (phosphanylidene‐σ 4 ‐phosphoranes, RP=PR 3 ) whose formation or reactions are reminiscent the coordination ligands in transition metal complexes.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNitric Oxide Cleavage: Synthesis of Terminal Chromium(VI) Nitrido Complexes via Nitrosyl DeoxygenationAaron L. Odom, Christopher C. Cummins, and John D. ProtasiewiczCite this: J. Am. Chem. Soc. 1995, 117, 24, 6613–6614Publication Date (Print):June 1, 1995Publication History Published online1 May 2002Published inissue 1 June 1995https://pubs.acs.org/doi/10.1021/ja00129a034https://doi.org/10.1021/ja00129a034research-articleACS PublicationsRequest...
Abstract Sterically‐encumbered ligands tethered to conjugated segments have been developed and employed in concert with existing bulky prepare a series of phospha ‐PPV oligomers. A study the variation λ π‐π* values along this indicates that low‐coordinate phosphorus centres can support conjugation across extended systems, generally confirms expected red shift from all‐carbon oligomers phosphaalkenes diphosphenes. These findings provide experimental evidence are fact capable supporting...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTVanadium-promoted reductive coupling of carbon monoxide and facile hydrogenation to form cis-disiloxyethylenesJohn D. Protasiewicz Stephen J. LippardCite this: Am. Chem. Soc. 1991, 113, 17, 6564–6570Publication Date (Print):August 1, 1991Publication History Published online1 May 2002Published inissue 1 August 1991https://pubs.acs.org/doi/10.1021/ja00017a030https://doi.org/10.1021/ja00017a030research-articleACS PublicationsRequest reuse...
The syntheses of benzoxaphospholes and new benzobisoxaphospholes that display blue fluorescence are presented. latter compounds were accessed by the use a precursor, 2,5-diphosphinohydroquinone. fully characterized, including structural study 2,6-tert-butylbenzo[1,2-d;4,5-d′]bisoxaphosphole. Quantum yields for photoluminescence determined series compounds. These materials feature bona fide P═C p−p π bonds suitable conjugated having phosphorus as participatory atom can thus "photocopy"...
Tetraarylphenyls of the form 2,3,5,6-Ar4C6 (Ar = p-tert-butylphenyl) are investigated as sterically demanding ligands for syntheses compounds having two p-phenylene-bridged phosphorus centers. The precursor to such materials, 1,4-diiodo-2,3,5,6-tetrakis(p-tert-butylphenyl)benzene (1), is readily obtained via a one-pot procedure in 68% yield. Compound 1 then used provide bis(dichlorophosphine) 1,4-bis(dichlorophosphino)-2,3,5,6-tetrakis(p-tert-butylphenyl)benzene (2) and derived...
The new sterically encumbered dichlorophosphine ArPCl2 (Ar = 2,6-dimesitylphenyl Dmp,l) has been prepared from the corresponding aryliodide, n-butyllithium, and phosphorus trichloride. DmpPC12 served as a precursor for phosphinic acid DmpP(O)(O
The reduction products of two diphosphaalkenes (1 and 2) a bis(diphosphene) (3) containing sterically encumbered ligands corresponding to the general formulas Ar-X=Y-Ar'-Y=X-Ar, have been investigated by EPR spectroscopy. Due steric constraints in these molecules, at least one dihedral angles between CXYC plane either Ar or Ar' is largely nonzero and, hence, discourages conformations that are optimal for maximal conjugation P=X (or P=Y) aromatic pi systems. Comparison experimental hyperfine...
Diphosphinite PCP-pincer pro-ligands anchored by a meta-terphenyl backbone were synthesized. These pro-ligands, [2,6-(2-Ph2POC6H4)2C6H3X] (3a X = I, 3b Br) and [2,6-(2-iPr2POC6H4)2C6H3X] (4a 4b upon reaction with Pd2(dba)3 yield PCP palladium pincer complexes [2,6-(2-Ph2POC6H4)2C6H3PdX] (5a 5b [2,6-(2-iPr2POC6H4)2C6H3PdX] (6a 6b Br). The structures of 5a−b 6a−b determined single crystal X-ray diffraction analyses. Complexes evaluated for their efficacy in promoting catalytic Suzuki−Miyaura...
The synthesis and characterization of the new diphosphenes DmtPPDmt (2a) (Dmt = 2,6-dimesityl-p-tolyl) DxpPPDxp (3a) (Dxp 2,6-di(m-xylyl)phenyl) are described. electrochemical behavior 2a, 3a, DmpPPDmp (1a) (Dmp 2,6-dimesitylphenyl) has been examined by cyclic voltammetry. Compounds 1a−3a display reversible reductions in THF (room temperature, 0.1 M nBu4NBF4) at −2.08, −2.15, −2.08 V vs SCE, respectively. Chemical reduction solutions led to stable radical anions [DmpPPDmp]•- (1b),...