Genetic Engineering & Biotechnology NewsVol. 33, No. 9 Legal AffairsDo Patents Control Self-Replicating Technologies?Supreme Court Hears Argument that Sale of Patented Seed Exhausts Future Patent RightsWilliam L. Warren and David E. WigleyWilliam L. WarrenSearch for more papers by this author and David E. WigleySearch for more papers by this authorPublished Online:29 Apr 2013https://doi.org/10.1089/gen.33.9.02AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View articleFiguresReferencesRelatedDetails Volume 33Issue 9May 2013 Information© 2013 by GEN PublishingTo cite this article:William L. Warren and David E. Wigley.Do Patents Control Self-Replicating Technologies?.Genetic Engineering & Biotechnology News.May 2013.8-8.http://doi.org/10.1089/gen.33.9.02Published in Volume: 33 Issue 9: April 29, 2013PDF download

Hydrodenitrogenation (HDN) catalysis is the process of removing nitrogen from petroleum feed-stocks in the form of NH3 to provide more processable and environmentally compatible liquid fuels. In practice, HDN is carried out simultaneously with other catalytic hydrotreating reactions such as hydrodesulfurization (HDS), yet HDN is significantly less well-studied than HDS. This contribution provides an overview of the heterogeneous HDN process, then outlines various homogeneous models for hydrodenitrogenation catalysis including binding modes of HDN substrates, catalytic hydrogenation processes and recent CN bond cleavage reactions of nitrogen heterocycles. Emphasis is placed on aryloxide and alkoxide complexes of the early metals that afford some of the best homogeneous models for hydrodenitrogenation catalysis to date.

We report the preparation of a stable metallapyridine complex of tantalum prepared in the coarse of model studies of hydrodenitrogenation reactions. Monomeric Ta(=NCtBu=CHCtBu=CH︹)(OAr)2(THF)(5⋅THF) is isolated upon thermolyzing the η2(N,C)-pyridine complex [η2(N,C)-2,4,6-NC5tBu3H2]Ta(OAr)2Me (2) in THF, while the metallapyridine dimer [Ta(μ−NCtBu=CH−−CtBu=CH︹)(OAr)2]2 (6) is isolated when this reaction is carried out in benzene. Complete NMR characterization of 5 · THF is described, along with its conversion into 6.

Hydrodenitrogenation (HDN) catalysis is the process of removing nitrogen from petroleum feedstocks in the form of NH3 to provide more processable and environmentally compatible liquid fuels. In practice, HDN is carried out simultaneously with other catalytic hydrotreating reactions such as hydrodesulfurization (HDS), yet HDN is significantly less well-studied than HDS. This contribution provides an overview of the heterogeneous HDN process, then outlines various homogeneous models for hydrodenitrogenation catalysis including binding modes of HDN substrates, catalytic hydrogenation processes and recent C--N bond cleavage reactions of nitrogen heterocycles. Emphasis is placed on aryloxide and alkoxide complexes of the early metals that afford some of the best homogeneous models for hydrodenitrogenation catalysis to date. (C) 1997 Elsevier Science Ltd.

The heterocyclic complexes [eta(1)(N)-QUIN]Ta(OAr)(3)Cl-2 (1) and [eta(1)(N)-6MQ] Ta(OAr)(3)Cl-2 (2) (where Ar = 2,6-diisopropylphenyl, QUIN = quinoline, and 6MQ = 6-methylquinoline) are prepared from Ta(OAr)(3)Cl-2(OEt(2)) and QUIN or 6MQ in pentane. [eta(1)(N)-6MQ]Ta(OAr)(2)Cl-3 (4) is prepared similarly from Ta(OAr)(3)Cl-2(OEt(2)). Upon rapid, two-electron reduction of these complexes, an eta(1)(N) --> eta(2)(N,C) bonding rearrangement is effected and the thermally sensitive, d(2) species [eta(2)(N,C)-QUIN]Ta(OAr)(3) (5), [eta(2)(N,C)-6MQ]Ta(OAr)(3) (6), and [eta(2)(N,C)-6MQ]Ta(OAr)(2)Cl(OEt(2)) (9) can be isolated. Alternatively, [eta(2)(N,C)-6MQ]Ta(OAr)(2)Cl(Oet(2)) (9) can be prepared in higher yield from (eta(6)-C(6)Me(6))Ta(OAr)(2)Cl and 6MQ. The trimethylphosphine adducts [eta(2)(N,C)-QUIN] Ta(OAr)(3)(PMe(3)) (7) and [eta(2)(N,C)-6MQ]Ta(OAr)(3)(PMe(3)) (8) can be prepared by simple coordination of PMe(3) to the base-free compounds 5 and 6. When Ta(OAr)(2)Cl-3(OEt(2)) is reduced by one electron in the presence of QUIN, 6MQ, or pyridine, the d(1) bis(ligand) complexes [eta(1)(N)-QUIN]Ta-2(OAr)(2)Cl-2 (10), [eta(1)(N)-6MQ]Ta-2(OAr)(2)Cl-2 (11), and [eta(1)(N)-py]Ta-2(OAr)(2)Cl-2 (12) can be isolated. Complexes 10 and 11 are not readily converted to the eta(2)(N,C) analogues 5 and 6 by further reduction. Under mild hydrogenation conditions, the only heterocyclic ligands which are hydrogenated are those bound in the eta(2)(N,C) mode to a d(2) metal. Structural studies on [eta(2)(N,C)-6MQ]Ta(OAr)(3)(PMe(3)) (8) and [eta(2)(N,C)-6MQ]Ta(OAr)(2)Cl (OEt(2)) (9) have been undertaken. [eta(2)(N,C) -6MQ]Ta(OAr)(3)(PMe(3)) (8) crystallizes in the monoclinic space group C2(1)/c (No. 15) with a = 32.849 (3) Angstrom, b = 19.579 (2) Angstrom, c = 23.822 (2) Angstrom, beta = 135.69 (49)degrees, and V = 10702 (2) Angstrom(3) with Z = 8 and rho(calcd) = 1.16 g cm(-3). [eta(2)(N,C)-6MQ]Ta(OAr)(2)Cl(OEt(2)) (9) crystallizes in the monoclinic space group P2(1)/n (No. 14) with a = 12.059 (9) Angstrom, b = 17.975 (14) Angstrom, c = 17.949 (13) Angstrom, beta = 100.29 (3)degrees, and V = 3828 (9) Angstrom(3) with Z = 4 and rho(calcd) = 1.37 g cm(-3). Both structures indicate an interruption of aromaticity to the heterocyclic ring only when bound in this fashion, consistent with the observation of 1,2,3,4-tetrahydroquinoline as the principal hydrogenation product of [eta(2)(N,C)-QUIN]Ta(OAr)(3) (5) with no decahydroquinoline being observed.

The bis(imido) complex of tungsten, W([double bond]NAr)[sub 2]Cl[sub 2](THF)[sub 2] (Ar = 2,6-C[sub 6]H[sub 3][sup i]Pr[sub 2]) reacts with Li[C[sub 5]Me[sub 5]] to provide burgundy ([eta][sup 5]-C[sub 5]Me[sub 5])W([double bond]NAr)[sub 2]Cl (1) in high yield. Compound 1 may be functionalized using MeLi, PhLi, or LiBEt[sub 3]H[sub *] (H[sup *] = H or D) to provide ([eta][sup 5]-C[sub 5]Me[sub 5])W([double bond]NAr)[sub 2]Me (2), ([eta][sup 5]-C[sub 5]Me[sub 5])W([double bond]NAr)[sub 2]Ph (3), ([eta][sup 5]-C[sub 5]Me[sub 5])W([double bond]NAr)[sub 2]H (4), and ([eta][sup 5]-C[sub 5]Me[sub 5])W([double bond]NAr)[sub 2]D (4-d) in moderate to high yields. ([eta][sup 5]-C[sub 5]Me[sub 5])W([double bond]NAr)[sub 2]Cl (1) crystallizes in the monoclinic P2[sub 1]/n (no. 14) [Angstrom][sup 3] with Z = 4 and [rho][sub calcd] = 1.46 g cm[sup [minus]3]. The molecular structure of 1 is characterized by nearly identical imido ligands with W-N-C[sub ipso] angles averaging 169.3 (4)[degrees] and W-N bonds averaging 1.783 (4) [Angstrom]. Upon reaction of ([eta][sup 5]-C[sub 5]Me[sub 5])W([double bond]NAr)[sub 2]Cl (1) with LiNHAr, the tucked-in complex ([eta][sup 5],[eta][sup 1]-C[sub 5]Me[sub 4]CH[sub 2])W([double bond]NAr)[sub 2] (5) is formed in nearly quantitative yield. Experiments are presented which indicate the most likely mechanism of formation of 5 involves the intermediacy of the substituted complex, ([eta][sup 5]-C[sub 5]Me[sub 5])W([double bond]NAr)[sub 2](NHAr).more » 48 refs., 1 fig., 3 tabs.« less

The bis(imido) complex of tungsten, W(=NAr)2Cl2(THF)2 (Ar = 2,6-C6H3iPr2) reacts with Li[C5Me5] to provide burgundy (eta5-C5Me5)W(=NAr)2Cl (1) in high yield. Compound 1 may be functionalized using MeLi, PhLi, or LiBEt3H* (H* = H or D) to provide (eta5-C5Me5)W(=NAr)2-Me (2), (eta5-C5Me5)W(=NAr)2Ph (3), (eta5-C5Me5)W(=NAr)2H (4), and (eta5-C5Me5)W(=NAr)2D (4-d) in moderate to high yields. (eta5-C5Me5)W(=NAr)2Cl (1) crystallizes in the monoclinic P2(1)/n (no. 14) with a = 11.880 (1) angstrom, b = 15.946 (1) angstrom, c = 17.703 (i) angstrom, beta = 73.65 (15)-degrees, and V = 3218.1 (17) angstrom3 with Z = 4 and rho(calcd) = 1.46 g CM-3. The molecular structure of 1 is characterized by nearly identical imido ligands with W-N-C(ipso) angles averaging 169.3 (4)-degrees and W-N bonds averaging l.783 (4) angstrom. Upon reaction of (eta5-C5Me5)W(=NAr)2Cl(l) with LiNHAr,the "tucked-in" complex (eta5,eta1-C5Me4CH2)W(=NAr)2 (5) is formed in nearly quantitative yield. Experiments are presented which indicate the most likely mechanism of formation of 5 involves the intermediacy of the substituted complex, (eta5-C5Me5)W(=NAr)2(NHAr).

The kinetic product from reducing Ta(DIPP)2Cl3(OEt2) (where DIPP = O-2,6-C6H3(i)Pr2) in the presence of HC = CCMe3 is the alpha,alpha' metallacyclopentadiene complex (DIPP)2Cl activated Ta(CCMe3 = CHCH = CCMe3) (1). Thermolysis of 1 provides the alpha,beta' isomer (DIPP)2Cl activated Ta(CCMe3 = CHCCMe3 = CH) (2). Kinetic and mechanistic studies of the 1 --> 2 isomerization are presented which lead to the proposal that the rearrangement proceeds by the disruption of the metallacycle and the formation of an intermediate Ta(V) metallacyclopropene (DIPP)2ClTa(HC = CCMe3) adduct, followed by its reaction with free HC = CCMe3 to reform the metallacycle. Compound 1 crystallizes in the monoclinic space group P2(1)/n (No. 14) with a = 12.130 (2) angstrom, b = 18.541 (3) angstrom, c = 15.844 (3) angstrom, beta = 95.48 (1)-degrees, and V = 3547.1 angstrom 3 with Z = 4 and rho(calcd) = 1.38 g cm-3. The final R = 0.029 and R(w) = 0.033 for 6835 reflections (6456 unique). Complex 1 assumes a TBP structure in the solid state with metallacyclic C(alpha) carbons occupying equatorial sites. Complex 2 (but not 1) engages in cycloaddition chemistry with HC = CCMe3 to afford the eta(6)-arene complex (eta(6)-1,3,5-C6H3(t)Bu3)Ta(DIPP)2Cl (6). 6 can be alkylated with MeMgBr to afford purple crystals of (eta(6)-1,3,5-C6H3(t)Bu3)Ta(DIPP)2(CH3) (7). Compound 7 crystallizes in the monoclinic space group P2(1)/n (No. 14) with a = 13.555 (1) angstrom, b = 20.607 (1) angstrom, c = 14.595 (1) angstrom, beta = 97.91 (6)-degrees, V = 4037.8 angstrom 3 with Z = 4 and rho(calcd) = 1.31 g cm-3. The final R = 0.024 and R(w) = 0.026 for 7686 reflections (6769 unique). The arene ligand in 7 exhibits a diene-diyl distortion and thus resembles a purported intermediate in the [2 + 2 + 2] cycloaddition of alkynes, the 7-metallanorbornadiene. Complex 2 (but not 1) forms adducts with THF and N = CCMe3, viz. (DIPP)2Cl(THF) activated Ta(CCMe3 = CHCCMe3 = CH) (5) and (DIPP)2Cl(Me3CC = N) activated Ta-(CCMe3 = CHCCMe3 = CH) (8). Compound 8 undergoes a cycloaddition reaction upon warming to room temperature to afford (eta(2)(N,C)-2,4,6-NC5H2(t)Bu3)Ta(DIPP)2Cl (9). Compound 9 crystallizes in the orthorhombic space group Pca2(1) (No. 29) with a = 20.674 (2) angstrom, b = 10.087 (5) angstrom, c = 19.908 (5) angstrom, and V = 4151.6 angstrom 3 with Z = 4 and rho(calcd) = 1.31 g cm-3. The final R = 0.037 and R(w) = 0.041 for 4153 reflections (3799 unique). The eta(2)-pyridine ligand in 9 is severely distorted, and spectroscopic and electrochemical studies on 9 reveal that the metal is in a higher effective oxidation state than the metal in the eta(6)-arene complex 6.

Ta(DIPP)3Cl2(OEt2) (DIPP = 2,6-diisopropylphenoxide) can be reduced by two electrons in the presence of the bulky alkynes PhC = CPh and Me3SiC = CMe to provide the pale yellow adducts (DIPP)3Ta-(PhC = CPh) (1) and (DIPP)3Ta(Me3SiC = CMe) (2). The reduction of Ta(DIPP)3Cl2(OEt2) in the presence of smaller internal alkynes (viz. EtC = CEt) or the terminal alkynes Me3SiC = CH or Me3CC = CH affords the metallacyclopentadienes (DIPP)3Ta-activated-(CEt = CEtCet = CEt) (3) or (DIPP)3Ta-activated-(CR = CHCR = CH) (4, R = SiMe3; 5, R = CMe3) directly. The molecular structure of the PhC = CPh adduct 1 is approximately tetrahedral (L-Ta-L angles average 109.4-degrees) and features very short Ta-C(alkyne) distances (2.070 (3) and 2.076 (3) angstrom, respectively) and an elongated "C = C" bond (1.346 (5) angstrom), which indicate a strongly bound and substantially reduced alkyne ligand. The molecular structure of metallacycle 3 reveals a trigonal bipyramidal geometry (L(ax)-Ta-L(ax) = 164.9 (3)-degrees) with the metallacyclic alpha carbons occupying one axial and one equatorial site. The alkyne complex (DIPP)3Ta(PhC = CPh) (1) reacts with MeC = CMe, EtC = CEt, Me3CC = CH, Me3SiC = CH, or PhC = CH to afford high yields of the metallacyclization products (DIPP)3Ta-activated-a(CPh = CPhCMe = CMe) (6), (DIPP)3Ta(CPh = CPhCEt = CEt) (7), (DIPP)3 Ta-activated (CPh = CPhCH = CCMe3) (8), (DIPP)3Ta-activated-(CPh = CPh CPhCH=?? = CSiMe3) (9), and (DIPP)3 Ta-acitvated-(CPh = CPhCH = CPh) (10), respectively, while 1,7-octadiyne HC = C(CH2)4C = CH reacts with 2 equiv of (DIPP)3Ta(PhC = CPh) to provide the unusual bimetallic complex (DIPP)3T-activated-a(CPh = CPhCH = C(CH2)4- C = CHCPh = PhC)Ta(DIPP)3 (11). The alkyne adduct (DIPP)3 Ta(Me3SiC = CMe) (2) also engages in metallacyclization chemistry as it reacts with MeC = CMe to afford (DIPP)3T-activated-a(CMe = CSiMe3CMe = CMe) (12), with PhC = CH to provide (DIPP)3T-activated-a(CSiMe3 = CMeCPh = CH) (13), and with Me3CC = CH to afford (DIPP)3T-activated-a(CCMe3 = CHCSiMe3 = CMe) (14). All of the metallacyclopentadiene complexes can be hydrolyzed with H2O/ acetone solutions to afford the corresponding 1,3-dienes in essentially quantitative yields. However, iodination of metallacycles 6, 7, and 13 does not yield the expected 1,4-diiodo-1,3-dienes but rather the ring-opened monoiodinated butadienyl compounds (DIPP)3(I)TaCPh = CPhCMe = CMe(I) (15), (DIPP)3(I)TaCPh = CPhCEt = CEt(I) (16), and (DIPP)3(I)TaCSiMe3 = CMeCPh = CH(I) (17), respectively. The subsequent hydrolysis of compounds 15-17 provides the corresponding 1-iodo-1,3-dienes.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and structural characterization of a Meerwein-Ponndorf-Verley/Oppenauer redox intermediate at a tantalum(V) centerJamie R. Strickler, Michael A. Bruck, Pamela A. Wexler, and David E. WigleyCite this: Organometallics 1990, 9, 1, 266–273Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Published inissue 1 January 1990https://doi.org/10.1021/om00115a039Request reuse permissionsArticle Views176Altmetric-Citations38LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

AbstractStarting with the tetrachloroalkyne complexes (III) or the tetrakis(arenethiolate) complexes (VII), the title complexes (I) and (II) are prepared as shown in the scheme.

AbstractDie Titelkomplexe (III) und (V) werden ausgehend von den Pentakis‐[isonitrill‐Komplexen (I) wie aufgezeichnet synthetisiert.

Treatment of ethanolic solutions of chromium(II) which are derived from the reduction of CrCl3 · 6H2O solutions) with excess phenyl isocyanide in the presence of KPF6 affords the complex [Cr(CNPh)5 Cl]PF6. Under similar conditions, p-tolyl isocyanide yields the chromium(I) complex [Cr(CN-p-tol)6PF6. The paramagnetic, yellow-green compound [Cr(CNPh)5 Cl]PF6 decomposes in dichloromethane solution to yield the chromium(II) species [Cr(CNPh)6](PF6)2. Treatment of dichloromethane solutions of [Cr(CNPh)5 Cl]PF6 with tertiary phosphines PR3 (PR3 = P-n-BU3, P-n-Pr3, PEt3 or PEt2 Ph) and with 1,2-bis(diphenylphosphino)ethane (dppe) gives paramagnetic trans-[Cr(CNPh)4(PR3)Cl]PF6 and [Cr(CNPh)3 (dppe)Cl]PF6. However, bis(diphenylphosphino)methane (dppm) reacts with [Cr(CNPh)5 Cl]PF6 to yield the diamagnetic, seven-coordinate complex [Cr[CNPh)5(dppm)(PF62. In the presence of excess P(OR)3 (R = Me or Et), ethanolic chromium(II) solutions and PhNC react to form [Cr(CNPh)5 Cl]PF6 whereas amines and phosphines lead to the formation of the homoleptic 18-electron compound Cr(CNPh)6.

AbstractDie Reaktionen der Nitrosyl‐Isocyanid‐Komplexe (I) mit einzähnigen Phosphinen führen zu den Substitutionsprodukten (II).