A5019971746- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Crystallography and molecular interactions
- Organometallic Complex Synthesis and Catalysis
- Catalytic C–H Functionalization Methods
- Inorganic Chemistry and Materials
- Synthesis and Catalytic Reactions
- Catalytic Cross-Coupling Reactions
- Asymmetric Hydrogenation and Catalysis
- Asymmetric Synthesis and Catalysis
- Cyclopropane Reaction Mechanisms
- Catalytic Alkyne Reactions
- Inorganic Fluorides and Related Compounds
- Marine Sponges and Natural Products
- Chemical Synthesis and Analysis
- Chemical synthesis and alkaloids
- Organic Light-Emitting Diodes Research
- Fluorine in Organic Chemistry
- Magnetism in coordination complexes
- Synthesis and characterization of novel inorganic/organometallic compounds
- Synthetic Organic Chemistry Methods
- Chemical Reactions and Mechanisms
- Carbon dioxide utilization in catalysis
- Microbial Natural Products and Biosynthesis
- Metal complexes synthesis and properties
University of North Texas at Dallas
2015-2024
University of North Texas
2024
The University of Texas at Arlington
2011-2020
Rice University
2016
The University of Texas Southwestern Medical Center
2012-2014
Brigham Young University
2014
Division of Chemistry
2012
California Institute of Technology
2005-2010
Scripps Research Institute
2009-2010
University of Southern California
2004-2010
The synthesis and photophysical characterization of a series (N,C(2')-(2-para-tolylpyridyl))2 Ir(LL') [(tpy)2 Ir(LL')] (LL' = 2,4-pentanedionato (acac), bis(pyrazolyl)borate ligands their analogues, diphosphine chelates tert-butylisocyanide (CN-t-Bu)) are reported. A smaller [(dfppy)2 (dfppy N,C(2')-2-(4',6'-difluorophenyl)pyridyl) complexes were also examined along with two previously reported compounds, (ppy)2 Ir(CN)2- Ir(NCS)2- (ppy N,C(2')-2-phenylpyridyl). (tpy)2 Ir(PPh2CH2)2 BPh2...
Two approaches are reported to achieve efficient blue near-UV emission from triscyclometalated iridium(III) materials related the previously complex, fac-Ir(ppz)3 (ppz = 1-phenylpyrazolyl-N,C2'). The first involves replacement of phenyl group ppz ligand with a 9,9-dimethyl-2-fluorenyl group, i.e., fac-tris(1-[(9,9-dimethyl-2-fluorenyl)]pyrazolyl-N,C2')iridium(III), abbreviated as fac-Ir(flz)3. Crystallographic analysis reveals that both fac-Ir(flz)3 and have similar coordination environment...
Despite the prevalence of N-H aziridine motif in bioactive natural products and clear advantages this unprotected parent structure over N-protected derivatives as a synthetic building block, no practical methods have emerged for direct synthesis compound class from unfunctionalized olefins. Here, we present mild, versatile method stereospecific conversion structurally diverse mono-, di-, tri-, tetrasubstituted olefins to aziridines using O-(2,4-dinitrophenyl)hydroxylamine (DPH) via...
Abstract We disclose an efficient and operationally simple protocol for the preparation of fused N‐heterocycles starting from readily available 2‐nitrobiaryls PhMgBr under mild conditions. More than two dozen N‐heterocycles, including bioactive natural products, have been synthesized using this method. A stepwise electrophilic aromatic cyclization mechanism was proposed by DFT calculations.
A new 3D fluorescent amide-functionalized Cd(II)-based metal–organic framework (MOF) with molecular formula [Cd5Cl6(L)(HL)2]·7H2O (1) was synthesized under solvothermal conditions using CdCl2·H2O and 4-(1H-tetrazol-5-yl)-N-[4-(1H-tetrazol-5-yl)phenyl]benzamide (H2L) in DMF/methanol the presence of conc. HCl. Single-crystal X-diffraction analysis reveals that structure 1 is constructed from octahedrally coordinated Cd2+ ions interconncted by chloride anions ditopic tetrazolate-based ligand...
A new series of luminescent mu-pyrazolate-bridged cyclometalated platinum binuclear complexes having the formula CwedgeNPt(mu-pz')2PtCwedgeN (CwedgeN = 2-(2,4-difluorophenyl)pyridyl, pz' pyrazolate for 1, 3,5-dimethylpyrazolate 2, 3-methyl-5-tert-butylpyrazolate 3, and 3,5-bis(tert-butyl)pyrazolate 4) have been synthesized characterized. The two Pt(CwedgeN) moieties are bridged by mu-pyrazolate ligands in an exo-bidentate fashion. mononuclear complex with isolated Pt center,...
The crystal structure of solvent-free Li2B12H12 has been determined by powder X-ray diffraction and confirmed a combination neutron vibrational spectroscopy first-principles calculations. This compound is possible intermediate in the dehydrogenation LiBH4, its structural characterization crucial for understanding decomposition regeneration LiBH4. Our results reveal that differs from other known alkali-metal (K, Rb, Cs) derivatives.
Abstract An organic acid catalyzed direct arylation of aromatic C(sp 2 )H bonds in phenols and naphthols for the preparation 1,1′‐linked functionalized biaryls was developed. The products are non‐C ‐symmetrical, atropoisomeric, represent previously untapped chemical space. Overall this transformation is operationally simple, does not require an external oxidant, readily scaled up (up to 98 mmol), structurally diverse 2,2′‐dihydroxy biaryl (i.e., BINOL‐type), as well 2‐amino‐2′‐hydroxy...
A transition-metal-free, regioselective direct aryl-aryl bond-forming process for the synthesis of halogenated 2-amino-2'-hydroxy-1,1'-biaryls that are currently either inaccessible or challenging to prepare using conventional methods is disclosed. The addition ArMgX an o-halonitrobenzene at low temperature generates a transient N,O-biarylhydroxylamine rapidly undergoes [3,3]- [5,5]-sigmatropic rearrangement in one-pot form 2-amino-2'-hydroxy-1,1'-biaryl 1-amino-1'-hydroxy-4,4'-biaryl,...
The Worldwide Protein Data Bank (wwPDB; wwpdb.org) is the international collaboration that manages deposition, processing and distribution of PDB archive. online archive at ftp://ftp.wwpdb.org repository for coordinates related information more than 47 000 structures, including proteins, nucleic acids large macromolecular complexes have been determined using X-ray crystallography, NMR electron microscopy techniques. members wwPDB–RCSB (USA), MSD-EBI (Europe), PDBj (Japan) BMRB (USA)–have...
(IPI)Ru(II)(OH)n(H2O)m, 2, where IPI is the NNN-pincer ligand, 2,6-diimidizoylpyridine, shown to catalyze H/D exchange between hydrocarbons and strongly basic solvents at higher rates than in case of solvent alone. Significantly, catalysis by 2 accelerated rather inhibited increasing basicity. The evidence consistent with reaction proceeding base modulated nucleophilic CH activation.
N-Heterocyclic carbene (NHC) ligand precursors, namely, HImACl [1,3-bis(2-ethoxy-2-oxoethyl)-1H-imidazol-3-ium chloride] and HImBCl {1,3-bis[2-(diethylamino)-2-oxoethyl]-1H-imidazol-3-ium chloride}, functionalized with hydrophilic groups on the imidazole rings have been synthesized were used in synthesis of corresponding complexes silver(I) copper(I), {[ImA]AgCl}, {[ImA]CuCl}, {[ImB]2Ag}Cl. Related AuINHC {[ImA]AuCl} {[ImB]AuCl} obtained by transmetalation using silver precursor. These...
We disclose a facile, aerobic, transition-metal-free, direct, and regiospecific mono-α-arylation of ketones to yield aryl benzyl (cyclo)alkyl with substitution patterns that are currently inaccessible or challenging prepare using conventional methods. The transformation is operationally simple, scalable, environmentally friendly. There no need for pre-functionalization (i.e., α-halogenation silyl enol ether formation) the use specialized arylating agents diaryliodonium salts). DFT...
N-heterocyclic carbene ligand SIDipp (SIDipp = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) and trimesitylphosphine have been used in the synthesis of gold(I) cyanide, t-butylisocyanide, cyclooctyne complexes (SIDipp)Au(CN) (3), (Mes(3)P)Au(CN) (4), [(Mes(3)P)(2)Au][Au(CN)(2)] (5), [(SIDipp)Au(CN(t)Bu)][SbF(6)] ([6][SbF(6)]), [(SIDipp)Au(cyclooctyne)][SbF(6)] ([8][SbF(6)]), [(Mes(3)P)Au(cyclooctyne)][SbF(6)] ([9][SbF(6)]). A detailed computational study has carried out on these...
Given the importance of amines in a large number biologically active natural products, pharmaceutical ingredients, agrochemicals, and functional materials, development efficient C–N bond-forming methods with wide substrate scope continues to be at frontier research synthetic organic chemistry. Here, we present general fundamentally new approach for direct, transition-metal-free preparation symmetrical unsymmetrical diaryl-, arylalkyl-, dialkylamines that relies on facile single or double...
Syntheses, structural, and photoluminescence properties of {[4-X-3,5-(CF3)2Pz]M}3 (X = Cl or Br, M Cu Ag) containing a heavier halide at the pyrazolyl ring 4-positions are reported. The Cu2O Ag2O react with [4-Cl-3,5-(CF3)2Pz]H [4-Br-3,5-(CF3)2Pz]H to form corresponding metal pyrazolates, which trinuclear adducts type nine-membered M3N6 metallacyclic core. They also feature relatively short M···Cl M···Br intertrimer separations (∼ 3.6 Å) leading supramolecular aggregates in solid state....
Bang on target: The highly explosive Group 6 azides Mo(N3)6 and W(N3)6 are prepared by the reaction of Me3SiN3 with MoF6 WF6, respectively. structure has perfect rhombohedral C3 symmetry (see picture). ionic leads to formation [Mo(N3)7]− [W(N3)7]−, respectively, first binary heptaazides. Controlled decomposition these anions produces [NMo(N3)4]− [NW(N3)4]−.
Discoidin domain receptor 2 (DDR2) is a tyrosine kinase involved in variety of cellular response pathways, including regulation cell growth, proliferation, and motility. Using newly developed platform to identify the signaling pathway/molecular target natural products, we identified family alkaloid discoipyrroles A-D (1-4), from Bacillus hunanensis that inhibit DDR2 pathway. The structure 1-4, determined by detailed two-dimensional (2D) NMR methods confirmed X-ray crystallographic analysis...
The tris(alkyne) copper complex [(cyclooctyne)3Cu][SbF6] has been synthesized using cyclooctyne and in situ generated CuSbF6. Tris(alkyne) silver complexes [(cyclooctyne)3Ag]+ involving weakly coordinating counterions such as [SbF6]− [PF6]− have also isolated good yield commercially available AgSbF6 AgPF6. These coinage metal adducts trigonal-planar sites. alkyne carbon atoms the site form distorted spoke-wheel (rather than upright trigonal-prismatic) structures solid state. In...
A new 3D zinc-organic framework [Zn(QDA)]·0.5H2O·0.7DMF (1, H2QDA = quinoline-2,6-dicarboxylic acid, DMF N,N-dimethylformamide) was synthesized under solvothermal conditions. The single crystal X-ray diffraction analysis reveals that the structure of 1 has a PtS topology and contains Zn(ii) ions having distorted square pyramidal geometry with ZnO4N configuration. phase purity bulk sample characterized by powder (XRPD), thermogravimetric (TGA) Fourier transform infrared (FT-IR) spectroscopy....
After all, neat As(N3)5 can be isolated: By analogy with AsCl5, was predicted to a highly unstable compound, and previous attempts at its synthesis had resulted in intense explosions. The successful syntheses characterization of Sb(N3)5 the crystal structure [Sb(N3)6]− ion (see picture) are now described.
Out of line? Theory predicts that [Ti(N3)4] should exhibit unprecedented linear TiNNN bond angles as a consequence the α-N atoms azide groups acting tridentate donors into empty tetrahedral d0 orbitals (+IV) Group 4 metal atom. The title compounds were prepared and characterized (see structure). They do not possess because their coordination numbers exceed four.
Cationic gold carbonyl complexes supported by N-heterocyclic carbene ligands, SIDipp and IDipp, have been synthesized. [(SIDipp)Au(CO)][SbF6] has a linear, two-coordinate center. [(IDipp)Au(CO)][SbF6] display CO values at 2197 2193 cm−1, respectively. Computational studies on [(SIMe)Au(CO)]+ indicate the presence of strong Au(I)–CO bond.
Golden trefoils: Tris(alkyne)gold complex [(coct)(3)Au][SbF(6)] (see picture; 1-SbF(6)) can be synthesized from cyclooctyne (coct) and AuSbF(6) generated in situ. Treatment of AuCl with led to the bis(alkyne)gold [Au(coct)(2)Cl] (2). DFT analysis indicates that ligands are net electron donors 1 but overall acceptors 2. is shown mediate [2+2+2] cycloaddition reactions alkynes.
Abstract An organic acid catalyzed direct arylation of aromatic C(sp 2 )H bonds in phenols and naphthols for the preparation 1,1′‐linked functionalized biaryls was developed. The products are non‐C ‐symmetrical, atropoisomeric, represent previously untapped chemical space. Overall this transformation is operationally simple, does not require an external oxidant, readily scaled up (up to 98 mmol), structurally diverse 2,2′‐dihydroxy biaryl (i.e., BINOL‐type), as well 2‐amino‐2′‐hydroxy...