Guochen Jia

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Organization: The Hong Kong University of Science and Technology , HongKong

Department: Department of Chemistry

Title: Professor(PhD)

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Organic Chemistry

Chemicals
References

Reactions of (Cyclopentadienylidenehydrazono)triphenylphosphorane with Chlororuthenium(II) Complexes and Substituent Effect on the Thermodynamic Trend in the Migratory-Insertion Reactions of Chlororuthenium–Alkylidene Complexes

Co-reporter:Wei Bai, Ka-Ho Lee, Jiangxi Chen, Herman H. Y. Sung, Ian D. Williams, Zhenyang Lin, and Guochen Jia

Organometallics September 11, 2017 Volume 36(Issue 17) pp:3266-3266

Publication Date(Web):August 29, 2017

DOI:10.1021/acs.organomet.7b00427

Reactions of (cyclopentadienylidenehydrazono)triphenylphosphorane with RuCl2(PPh3)3 or (η6-cymene)RuCl2(PPh3) in toluene produced the chlorocyclopentadienyl complex (η5-C5H4Cl)RuCl(PPh3)2, which was likely formed through the cyclopentadienylidene intermediate RuCl2{═C(C4H4)}(PPh3)2. Treatment of (η6-cymene)RuCl2(PPh3) with (cyclopentadienylidenehydrazono)triphenylphosphorane in methanol gave [(η5-C5H4Cl)Ru(η6-cymene)]+. Computational studies reveal that the thermodynamic stability of the analogous chlororuthenium complexes RuCl2(═CRR′)(PPh3)2 and [RuCl(═CRR′)(PMe3)(η6-C6H6)]+, with respect to the formation of the corresponding η5-chloropentadienyl complexes via a migratory carbene-insertion reaction is in the order of cyclopentadienylidene < indenylidene < fluorenylidene < phenylcarbene.

Synthesis and Reactivities of Polyhydrido Osmium Arylsilyl Complexes Prepared from OsH3Cl(PPh3)3

Co-reporter:Guomei He, Linlin Wu, Wei Bai, Jiangxi Chen, Herman H. Y. Sung, Ian D. Williams, Zhenyang Lin, and Guochen Jia

Organometallics October 9, 2017 Volume 36(Issue 19) pp:3729-3729

Publication Date(Web):September 25, 2017

DOI:10.1021/acs.organomet.7b00512

Reactions of silanes with transition-metal complexes are of interest because their relevance to Si–H bond activation, the structural properties of polyhydrides, and catalytic hydrosilylation reactions. This work presents the results derived from reactions of arylsilanes Ph2SiH2 and PhSiH3 with OsH3Cl(PPh3)3 (1). Reaction of 1 with 1 equiv or excess Ph2SiH2 affords OsH3(SiClPh2)(PPh3)3 (2) or OsH4(SiClPh2)(SiHPh2)(PPh3)2 (3), respectively. These silyl complexes are formed via the oxidative addition of Si–H bonds and H/Cl exchange via silylene intermediates. Similarly, reaction of 1 with excess PhSiH3 produced the analogous bis(silyl) complex OsH4(SiClHPh)(SiH2Ph)(PPh3)2 (4). The bis(silyl) complexes are dodecahedral tetrahydride complexes containing weak Si···H interactions. The complex 3 reacts with PPh3 and CH3CN to selectively eliminate Ph2SiH2. Computational studies show that the preference for reductive eliminations from 3 follows the order Ph2SiH2 > H2 > Ph2SiHCl > Ph2HSi-SiClPh2.

Reactions of Osmium Carbyne Complexes OsCl3(≡CR)(PPh3)2 (R = CH═CPh2, CH2Ar) with Bromine and Hydrogen Peroxide

Co-reporter:Wei Bai;Ka-Ho Lee;Wai Yiu Hung;Herman H. Y. Sung;Ian D. Williams;Zhenyang Lin

Organometallics February 13, 2017 Volume 36(Issue 3) pp:657-664

Publication Date(Web):January 18, 2017

DOI:10.1021/acs.organomet.6b00860

The reactions of the trichloro carbyne complexes OsCl3(≡CR)(PPh3)2 (R = CH═CPh2, CH2Ar) with bromine and hydrogen peroxide were studied. Unlike monochloro carbyne complexes OsCl(≡CAr)(CO)(PPh3)2, the trichloro complexes OsCl3(≡CR)(PPh3)2 do not undergo oxidation reactions at the metal center or the metal–carbyne bond. Treatment of OsCl3(≡CCH═CPh2)(PPh3)2 with Br2/H2O and H2O2/HCl produced OsBr3(≡CCH═CPh2)(H2O)(PPh3) and OsCl3(≡CCCl═CPh2)(PPh3)2, respectively. Reactions of OsCl3(≡CCH2-C6H4-p-R)(PPh3)2 (R = H, CMe3) with H2O2/HCl or H2O2 gave OsCl3{≡CC(O)-C6H4-p-R}(PPh3)2. Computational studies suggest that the difference in the reactivity of OsCl(≡CAr)(CO)(PPh3)2 and OsCl3(≡CR)(PPh3)2 is mainly of thermodynamic origin.

Preparation of Osmium η3-Allenylcarbene Complexes and Their Uses for the Syntheses of Osmabenzyne Complexes

Co-reporter:Ting Bin Wen, Ka-Ho Lee, Jiangxi Chen, Wai Yiu Hung, Wei Bai, Huacheng Li, Herman H. Y. Sung, Ian D. Williams, Zhenyang Lin, and Guochen Jia

Organometallics 2016 Volume 35(Issue 10) pp:1514-1525

Publication Date(Web):March 29, 2016

DOI:10.1021/acs.organomet.6b00102

Treatment of OsCl2(PPh3)3 with HC≡CAr (Ar = Ph, p-tolyl) produced the η3-allenylcarbene complexes OsCl2(═CAr-η2-CH═C═CHAr)(PPh3)2. Reactions of the η3-allenylcarbene complexes with gold alkynyls Au(C≡CR)(PPh3) (R = Ph, p-tolyl, TMS, nBu, CH(OEt)2) or copper(I) alkynyls Cu(C≡CR) (R = Ph, TMS) in the presence of HNEt3Cl produced the osmabenzynes Os{≡CC(R)═C(CH2Ar)CH═CAr}Cl2(PPh3)2. Computational studies suggest that the osmabenzynes are formed through electrocyclization of osmium alkynyl-allenylcarbene intermediates followed by protonation with HNEt3Cl.

Synthesis of Rhenium Vinylidene and Carbyne Complexes from Reactions of [Re(dppm)3]I with Terminal Alkynes and Alkynols

Co-reporter:Ka Wing Chan, Wei Bai, Kui Fun Lee, Ka-Ho Lee, Herman H. Y. Sung, Ian D. Williams, Zhenyang Lin, and Guochen Jia

Organometallics 2016 Volume 35(Issue 20) pp:3520-3529

Publication Date(Web):October 3, 2016

DOI:10.1021/acs.organomet.6b00568

Treatment of [Re(dppm)3]I (dppm = PPh2CH2PPh2) with HC≡CPh produced the rhenium vinylidene complex ReI(═C═CHPh)(dppm)2. In the presence of HI, [Re(dppm)3]I reacted with HC≡CR (R = Ph, p-tolyl, C6H4-o-CHO, (CH2)5CH3) to give the rhenium carbyne complexes [ReI(≡CCH2R)(dppm)2]I and with HC≡CSiMe3 to give [ReI(≡CMe)(dppm)2]I. One-pot reactions of [Re(dppm)3]I, HC≡CC(OH)RR′ (RR′ = Ph2, Me2, PhMe), and HI produced the vinylcarbyne complexes [ReI(≡CCH═CRR′)(dppm)2]I.

Alkyne Metathesis Reactions of Rhenium(V) Carbyne Complexes

Co-reporter:Wei Bai, Ka-Ho Lee, Herman H. Y. Sung, Ian D. Williams, Zhenyang Lin, and Guochen Jia

Organometallics 2016 Volume 35(Issue 22) pp:3808-3815

Publication Date(Web):November 15, 2016

DOI:10.1021/acs.organomet.6b00653

Although alkyne metathesis reactions mediated by high-valent d0 carbyne complexes are well established, similar reactions mediated by well-defined low-valent (non-d0) carbyne complexes are rare. This work demonstrates that d2 Re(V) carbyne complexes Re(≡CR)Cl2(PMe2Ph)3 (R = CH2(o-C6H4Br), Ph, CO2Et) can undergo stoichiometric alkyne metathesis reactions. For example, reactions of Re{≡CCH2(o-C6H4Br)}Cl2(PMe2Ph)3 with TMSC≡CR (R = CO2Et, CH2Ph) and PhC≡CPh produced carbyne complexes Re(≡CR)Cl2(PMe2Ph)3 and Re(≡CPh)Cl2(PMe2Ph)3, respectively. Theoretical studies suggest that the metathesis reactions most likely proceed through six-coordinate alkyne-carbyne intermediates Re(≡CR)Cl2(η2-alkyne)(PMe2Ph)2 that undergo reversible cycloaddition reactions.

Ruthenium-catalyzed β-alkylation of secondary alcohols with primary alcohols

Co-reporter:Wei Bai, Guochen Jia

Inorganica Chimica Acta 2015 Volume 431() pp:234-241

Publication Date(Web):24 May 2015

DOI:10.1016/j.ica.2015.03.023

•The catalytic properties of 19 ruthenium complexes are compared.•RuCl2(PPh3)2(2-NH2CH2Py) is the most active catalytic precursor found in this study.•β-Alkylation of secondary alcohols with benzylic and alkyl primary alcohols can be achieved.The catalytic properties of a series of ruthenium complexes for β-alkylation of secondary alcohols with primary alcohols were studied. The catalytic activities of the ruthenium complexes were found to be dependent on the auxiliary ligands. The most active catalytic precursor found in this study is the ruthenium complex RuCl2(PPh3)2(2-NH2CH2Py) [2-NH2CH2Py = 2-aminomethyl pyridine], which effectively catalyzed the β-alkylation of both aryl- and alkyl-substituted secondary alcohols with benzylic and alkyl primary alcohols.The ruthenium complex RuCl2(PPh3)2(2-NH2CH2Py) [2-NH2CH2Py = 2-aminomethyl pyridine] effectively catalyzed the β-alkylation of both aryl- and alkyl-substituted secondary alcohols with benzylic and alkyl primary alcohols.

Ruthenium-Catalyzed Deuteration of Alcohols with Deuterium Oxide

Co-reporter:Wei Bai, Ka-Ho Lee, Sunny Kai San Tse, Ka Wing Chan, Zhenyang Lin, and Guochen Jia

Organometallics 2015 Volume 34(Issue 15) pp:3686-3698

Publication Date(Web):July 20, 2015

DOI:10.1021/acs.organomet.5b00134

The catalytic properties of a series of ruthenium complexes for H/D exchange between D2O and alcohols were studied. The catalytic activity of the ruthenium complexes and the regioselectivity of the H/D exchange reactions were found to be dependent on the auxiliary ligands. While ruthenium η6-cymene complexes such as [(η6-cymene)RuCl(NH2CH2CH2NTs)]Cl, (η6-cymene)RuCl2/NH2CH2CH2OH, and (η6-cymene)Ru{(S,S)-NHCHPhCHPhNTs} catalyzed regioselective deuteration of alcohols with D2O at the β-carbon positions only, octahedral ruthenium complexes such as RuCl2(2-NH2CH2Py)(PPh3)2 (2-NH2CH2Py = 2-aminomethylpyridine) and RuCl2(NH2CH2CH2NH2)(PPh3)2 catalyzed regioselective H/D exchange reactions of D2O with alcohols at both the α- and β-carbon positions of alcohols. The H/D exchange reactions proceed through reversible dehydrogenation of alcohols and hydrogenation of carbonyl compounds involving hydride species and H/D exchange among D2O and carbonyl and hydride species. The different regioselectivities of the H/D exchange reactions can be related to the relative ease of H/D exchange of ruthenium hydride intermediates with D2O.

Rearrangement of Metallabenzynes to Chlorocyclopentadienyl Complexes

Co-reporter:Jiangxi Chen, Ka-Ho Lee, Tingbin Wen, Feng Gao, Herman H. Y. Sung, Ian D. Williams, Zhenyang Lin, and Guochen Jia

Organometallics 2015 Volume 34(Issue 5) pp:890-896

Publication Date(Web):February 27, 2015

DOI:10.1021/om501181u

Treatment of the osmabenzyne complex Os{≡C-C(SiMe3)═C(CH3)-C(SiMe3)═CH−}Cl2(PPh3)2 with Mo(CO)6 in refluxing benzene produced the η5-chlorocyclopentadienyl complex Os{η5-C5HCl(CH3)(SiMe3)2}Cl(CO)(PPh3) and Mo(CO)5(PPh3). A computational study suggests that the chlorocyclopentadienyl complex is most likely produced via the carbene intermediate Os{═C(C(SiMe3)═C(CH3)-C(SiMe3)═CH−)}Cl2(CO)(PPh3) formed by a migratory insertion reaction of the osmabenzyne complex Os{≡C-C(SiMe3)═C(CH3)-C(SiMe3)═CH}Cl2(CO)(PPh3). DFT calculations show that the relative thermal stability of metallabenzynes Os(≡C-CH═CHCH═CH)Cl2(L)2 and the corresponding isomeric carbene complexes Os{═C(−CH═CHCH═CH−)}Cl2(L)2 as well as the chlorocyclopentadienyl complexes Os(η5-C5ClH4)Cl(L)2 (L = CO, phosphine, pyridine, amine) is strongly dependent on ligand L.

Rhenabenzenes and Unexpected Coupling Products from the Reactions of Rhenacyclobutadienes with Ethoxyethyne

Co-reporter:Ran Lin, Ka-Ho Lee, Herman H. Y. Sung, Ian D. Williams, Zhenyang Lin, and Guochen Jia

Organometallics 2015 Volume 34(Issue 1) pp:167-176

Publication Date(Web):December 24, 2014

DOI:10.1021/om501034e

Treatment of Na[Re(CO)5] with methyl 3-(naphthalen-1-yl)propiolate (NpC≡CCO2Me) followed by acetyl chloride and alcohols ROH (R = Me, nPr) afforded the rhenacyclobutadiene complexes Re{-C(Np)═C(CO2Me)C(OR)═}(CO)4. Reactions of these rhenacyclobutadiene complexes with HC≡COEt produced the rhenabenzene complexes Re{-C(Np)═C(CO2Me)C(OR)═CHC(OEt)═}(CO)4 and new rhenacyclobutadienes with a pendant vinyl substituent Re{-C(Np)═C(C(OR)═CH(CO2Et))C(OMe)═}(CO)4. In the vinyl-substituted rhenacyclobutadiene products, the ethyl of the ester group is from the alkyne HC≡COEt, the alkyl of the ReC(OR) group is from the ester group of the starting rhenacyclobutadienes, and the alkyl group of the OR of the vinyl substituent is from the ReC(OR) group of the starting rhenacyclobutadienes. A plausible mechanism for the formation of the vinyl-substituted rhenacyclobutadienes is discussed.

Iridium-Catalyzed Intermolecular AzideAlkyne Cycloaddition of Internal Thioalkynes under Mild Conditions

Co-reporter:Shengtao Ding; Guochen Jia; Jianwei Sun

Angewandte Chemie International Edition 2014 Volume 53( Issue 7) pp:1877-1880

Publication Date(Web):

DOI:10.1002/anie.201309855

Abstract

An iridium-catalyzed azide–alkyne cycloaddition reaction (IrAAC) of electron-rich internal alkynes is described. It is the first efficient intermolecular AAC of internal thioalkynes. The reaction exhibits remarkable features, such as high efficiency and regioselectivity, mild reaction conditions, easy operation, and excellent compatibility with air and a broad spectrum of organic and aqueous solvents. It complements the well-known CuAAC and RuAAC click reactions.

Synthesis of Rhenabenzenes from the Reactions of Rhenacyclobutadienes with Ethoxyethyne

Co-reporter:Dr. Ran Lin;Ka-Ho Lee;Dr. Ka Chun Poon;Dr. Herman H. Y. Sung; Ian D. Williams; Zhenyang Lin; Guochen Jia

Chemistry - A European Journal 2014 Volume 20( Issue 45) pp:14885-14899

Publication Date(Web):

DOI:10.1002/chem.201403186

Abstract

Treatment of Na[Re(CO)₅] with RCCCO₂Et (R=phenyl, naphthalen-1-yl, phenanthren-9-yl and pyren-1-yl) followed by reaction with acetyl chloride and ethanol afforded the rhenacyclobutadienes Re{-C(R)C(CO₂Et)C(OEt)}(CO)₄. Reactions of these rhenacyclobutadienes with HCCOEt produced rhenabenzenes Re{-C(R)C(CO₂Et)C(OEt)CHC(OEt)}(CO)₄. Except for R=Ph, new rhenacyclobutadienes with pendant alkenyl substituents Re{-C(R)C(C(OEt)CH(CO₂Et))C(OEt)}(CO)₄ were also isolated from these reactions. The NMR spectroscopic and X-ray structural data, as well as the aromatic stabilization energy (ASE) values suggest that the rhenabenzenes are aromatic, with extensive delocalized π character.

Theoretical Studies on the Regioselectivity of Iridium-Catalyzed 1,3-Dipolar Azide–Alkyne Cycloaddition Reactions

Co-reporter:Qiong Luo, Guochen Jia, Jianwei Sun, and Zhenyang Lin

The Journal of Organic Chemistry 2014 Volume 79(Issue 24) pp:11970-11980

Publication Date(Web):September 15, 2014

DOI:10.1021/jo5018348

Iridium-catalyzed cycloaddition of thioalkynes and bromoalkynes with azides have been investigated with the aid of density functional theory (DFT) calculations at the M06 level of theory. Our investigation focused on the different regioselectivity observed for the reactions of the two classes of alkynes. The DFT results have shown that the mechanisms of cycloaddition reactions using thioalkynes and bromoalkynes as substrates are similar yet different. The reactions of thioalkynes occur via a metallabicyclic Ir–carbene intermediate formed through alkyne–azide oxidative coupling via attack of the azide terminal nitrogen toward the β alkyne carbon, whose carbene ligand is stabilized by an alkylthio/arylthio substituent. Reductive elimination from the intermediate leads to the formation of the experimentally observed 5-sulfenyltriazole. In the reactions of bromoalkynes RC≡CBr, the reaction mechanism involves the initial formation of a six-membered-ring metallacycle intermediate in the oxidative coupling step. The six-membered-ring intermediate then undergoes isomerization via migrating the terminal azide nitrogen from the β carbon to the α carbon to form a much less stable metallabicyclic Ir–carbene species from which reductive elimination gives 4-bromotriazole.

Synthesis and characterization of MH⋯HOR dihydrogen bonded ruthenium and osmium complexes (η5-C5H4CH2OH)MH(PPh3)2 (M = Ru, Os)

Co-reporter:Wei Bai;Sunny Kai San Tse;Ka Ho Lee;Herman Ho-Yung Sung

Science China Chemistry 2014 Volume 57( Issue 8) pp:1079-1089

Publication Date(Web):2014 August

DOI:10.1007/s11426-014-5143-6

Treatment of RuCl2(PPh3)3 with 6-dimethylaminopentafulvene in THF in the presence of water produced (η5-C5H4CHO) RuCl(PPh3)2, which was reduced by NaBH4 to give the Ru-H⋯HO dihydrogen bonded complex (η5-C5H4CH2OH) RuH(PPh3)2. The dihydrogen bonded complex (η5-C5H4CH2OH)RuH(PPh3)2 could also be synthesized by the reduction of complex (η5-C5H4CHO)RuH(PPh3)2, which was obtained by the reaction of RuHCl(PPh3)3 with 6-dimethylaminopentafulvene in the presence of water. The analogous dihydrogen bonded osmium complex (η5-C5H4CH2OH)OsH(PPh3)2 was similarly prepared. Single crystal structures and DFT calculations support the presence of intra-molecular H…H interaction, with separations of around 1.9 to 2.0 Å.

Iridium-Catalyzed Intermolecular AzideAlkyne Cycloaddition of Internal Thioalkynes under Mild Conditions

Co-reporter:Shengtao Ding; Guochen Jia; Jianwei Sun

Angewandte Chemie 2014 Volume 126( Issue 7) pp:1908-1911

Publication Date(Web):

DOI:10.1002/ange.201309855

Abstract

Chemistry of rhenium carbyne complexes

Co-reporter:Chuan Shi, Guochen Jia

Coordination Chemistry Reviews 2013 Volume 257(3–4) pp:666-701

Publication Date(Web):February 2013

DOI:10.1016/j.ccr.2012.08.005

There has been much interest in the chemistry of rhenium carbyne complexes, complexes with a rhenium–carbon triple bond. A number of rhenium carbyne complexes have been obtained from various synthetic routes. A variety of interesting chemical properties of rhenium carbyne complexes have also been reported. This review summarizes the work related to the synthesis and reactivity of mononuclear rhenium carbyne complexes.Highlights► The synthesis and reactivities of mononuclear rhenium carbyne complexes are reviewed. ► Synthetic routes to rhenium carbyne complexes are summarized. ► Chemical properties of rhenium carbyne complexes are discussed. ► The structural properties of rhenium carbyne complexes are addressed.

Recent development in the chemistry of transition metal-containing metallabenzenes and metallabenzynes

Co-reporter:Jiangxi Chen, Guochen Jia

Coordination Chemistry Reviews 2013 Volume 257(17–18) pp:2491-2521

Publication Date(Web):September 2013

DOI:10.1016/j.ccr.2013.01.014

Transition metal-containing metallabenzenes and metallabenzynes are organometallic compounds derived from formal replacement of a CH group or a C atom in benzene and benzyne by an isolobal transition metal fragment. The chemistry of these interesting metallaaromatics has received considerable attention in recent years. A number of such complexes have been obtained from various synthetic routes. Interesting chemical properties of these complexes have also been reported. This review summarizes recent progress in the synthesis and reactivity of metallabenzenes and metallabenzynes.Highlights► The recent progress in the chemistry of metallabenzenes and metallabenzynes are reviewed. ► Synthetic routes to metallabenzenes and metallabenzynes are summarized. ► Chemical properties of metallabenzenes and metallabenzynes are described. ► The aromatic properties of metallabenzenes and metallabenzynes are discussed.

Our Journey to the Chemistry of Metallabenzynes

Co-reporter:Guochen Jia

Organometallics 2013 Volume 32(Issue 23) pp:6852-6866

Publication Date(Web):October 14, 2013

DOI:10.1021/om400716v

This personal account summarizes our work on the chemistry of transition-metal-containing metallabenzynes, organometallic compounds derived from formal replacement of a C atom in benzyne by an isolobal transition-metal fragment. Metallabenzynes with osmium and rhenium have been synthesized and well characterized. They have aromatic character on the basis of the criteria of reactivity, geometry, aromatic stabilization energy, and magnetic properties. They can undergo typical reactions of aromatic systems (e.g., electrophilic substitution reactions) and organometallic complexes (e.g., reductive elimination reactions to form carbene complexes).

Palladium-Catalyzed Decarboxylation of Allenyl 3-Oxoalkanoates: An Efficient Synthesis of 3,4-Allenyl Ketones

Co-reporter:Baoqiang Wan, Guochen Jia, and Shengming Ma

Organic Letters 2012 Volume 14(Issue 1) pp:46-49

Publication Date(Web):December 16, 2011

DOI:10.1021/ol202786y

An efficient synthesis of 3,4-allenyl ketones via the Pd-catalyzed decarboxylative coupling of the readily available 3-oxoalkanoates is reported. The C–C bond forming reaction occurs under mild conditions producing CO2 as the only byproduct.

RuH2(CO)(PPh3)3 Catalyzed Selective Formation of 1,4-Disubstituted Triazoles from Cycloaddition of Alkynes and Organic Azides

Co-reporter:Pei Nian Liu, Hai Xiao Siyang, Li Zhang, Sunny Kai San Tse, and Guochen Jia

The Journal of Organic Chemistry 2012 Volume 77(Issue 13) pp:5844-5849

Publication Date(Web):June 6, 2012

DOI:10.1021/jo3008572

The ruthenium hydride complex RuH2(CO)(PPh3)3 was found to be an effective catalyst for the cycloaddition reactions of terminal alkynes and azides. In the presence of RuH2(CO)(PPh3)3, various azides reacted with a range of terminal alkynes to produce 1,4-disubstituted 1,2,3-triazoles with 100% selectivity and moderate to excellent yields.

Selective Formation of 1,4-Disubstituted Triazoles from Ruthenium-Catalyzed Cycloaddition of Terminal Alkynes and Organic Azides: Scope and Reaction Mechanism

Co-reporter:Pei Nian Liu, Juan Li, Fu Hai Su, Kun Dong Ju, Li Zhang, Chuan Shi, Herman H. Y. Sung, Ian D. Williams, Valery V. Fokin, Zhenyang Lin, and Guochen Jia

Organometallics 2012 Volume 31(Issue 13) pp:4904-4915

Publication Date(Web):June 26, 2012

DOI:10.1021/om300513w

The catalytic activity of a series of ruthenium complexes lacking cyclopentadienyl ligands has been evaluated for the cycloaddition of terminal alkynes and azides to give selectively 1,4-disubstituted 1,2,3-triazoles. The complex RuH(η2-BH4)(CO)(PCy3)2 was found to be an effective catalyst for the cycloaddition reactions. In the presence of RuH(η2-BH4)(CO)(PCy3)2, primary and secondary azides reacted with a range of terminal alkynes containing various functionalities to selectively produce 1,4-disubstituted 1,2,3-triazoles. The ruthenium-catalyzed azide–alkyne cycloaddition appears to proceed via a Ru–acetylide species as the key intermediate, which undergoes formal cycloaddition with an azide to give a ruthenium triazolide complex. The 1,4-disubstituted 1,2,3-triazole product is generated by metathesis of the triazolide complex with a terminal alkyne. In support of the reaction mechanism, the acetylide complex Ru(C≡CCMe3)2(CO)(PPh3)3 reacts cleanly with benzyl azide to give a ruthenium triazolide complex, which reacts with excess tert-butylacetylene in the presence of PPh3 to give 4-tert-butyl-1-benzyl-1,2,3-triazole and the diacetylide complex Ru(C≡CCMe3)2(CO)(PPh3)3. The mechanism is also supported by DFT calculations.

Hydrogen Shift Reactions of Rhenium Hydrido Carbyne Complexes

Co-reporter:Jiangxi Chen, Chuan Shi, Herman Ho-Yung Sung, Ian Duncan Williams, Zhenyang Lin, and Guochen Jia

Organometallics 2012 Volume 31(Issue 5) pp:1817-1824

Publication Date(Web):February 9, 2012

DOI:10.1021/om201184m

Rhenium hydrido carbyne complexes Re(≡CCH═C(CMe3)C≡CR)HCl(PMe2Ph)3 (R = H, n-pentyl) undergo 1,2-hydrogen shift reactions from the metal to the carbyne carbon atom to give complexes Re(HCCHC(CMe3)CCR)HCl(PMe2Ph)3, which have two isomeric forms, namely, a metallabicyclo[3.1.0]hexatriene complex, in which the chloride is cis to the metal-bonded CH, and an alkyne–carbene complex, in which the chloride is trans to the metal-bonded CH. In contrast, a similar transformation does not occur for the analogous complex Re(≡CCH═C(CMe3)C≡CSiMe3)HCl(PMe2Ph)3, which has a SiMe3 group on the C≡C moiety. A computational study suggests that the difference in the reactivity of the hydrido carbyne complexes is related to steric effects in the corresponding hydride-shift products. Formation of Re(HCCHC(CMe3)CCSiMe3)HCl(PMe2Ph)3 is not favored, mainly due to the steric interactions of the SiMe3 group with CMe3 and one of the phosphine ligands in the resulting metallabicyclo[3.1.0]hexatriene complex, and of the SiMe3 group with the chloride ligand in the resulting alkyne–carbene complex.

Synthesis and Characterization of Rhenabenzyne Complexes

Co-reporter:Dr. Jiangxi Chen;Chuan Shi;Dr. Herman H. Y. Sung; Ian D. Williams; Zhenyang Lin; Guochen Jia

Chemistry - A European Journal 2012 Volume 18( Issue 44) pp:14128-14139

Publication Date(Web):

DOI:10.1002/chem.201202012

Abstract

Reactions of [ReH₅(PMe₂Ph)₃] with alkynols HC≡CC(OH)(R)C≡CSiMe₃ (R=tBu, iPr, 1-adamantyl) in the presence of HCl give the vinylcarbyne complexes [Re{≡CCHC(R)C≡CSiMe₃}Cl₂(PMe₂Ph)₃], which react with tBuMgCl to give [Re{≡CCHC(R)C≡CSiMe₃}HCl(PMe₂Ph)₃]. Treatment of [Re{≡CCHC(R)C≡CSiMe₃}HCl(PMe₂Ph)₃] with nBu₄NF gives [Re{≡CCHC(R)C≡CH}HCl(PMe₂Ph)₃], which first isomerizes to the bicyclic complexes [Re{CHCHC(R)CCH}Cl(PMe₂Ph)₃], and then to the rhenabenzynes [Re{≡CCHC(R)CHCH}Cl(PMe₂Ph)₃]. The NMR spectroscopic and structural data as well as the aromatic stabilization energy (ASE) and nucleus-independent chemical-shift (NICS) values suggest that these rhenabenzynes have aromatic character.

Electrophilic Substitution Reactions of Metallabenzynes

Co-reporter:Wai Yiu Hung ; Bin Liu ; Wangge Shou ; Ting Bin Wen ; Chuan Shi ; Herman H.-Y. Sung ; Ian D. Williams ; Zhenyang Lin

Journal of the American Chemical Society 2011 Volume 133(Issue 45) pp:18350-18360

Publication Date(Web):October 13, 2011

DOI:10.1021/ja207315h

The electrophilic substitution reactions of metallabenzynes Os(≡CC(R)═C(CH3)C(R)═CH)Cl2(PPh3)2 (R = SiMe3, H) were studied. These metallabenzynes react with electrophilic reagents, including Br2, NO2BF4, NOBF4, HCl/H2O2, and AlCl3/H2O2 to afford the corresponding bromination, nitration, nitrosation, and chlorination products. The reactions usually occur at the C2 and C4 positions of the metallacycle. These observations support the notion that metallabenzynes exhibit aromatic properties.

Palladium-Catalyzed Highly Chemo-, Regio- and Stereoselective Synthesis of Eight- to Ten-Membered Lactones from Allenyl 3-Oxoalkanoates and Organic Halides

Co-reporter:Baoqiang Wan;Shengming Ma

Advanced Synthesis & Catalysis 2011 Volume 353( Issue 10) pp:1763-1774

Publication Date(Web):

DOI:10.1002/adsc.201100075

Abstract

A highly chemo-, regio-, and stereoselective synthesis of eight- to ten-membered lactones via the coupling cyclization of readily available allenyl 3-oxoalkanoates and organic halides through an anti-π-allylic palladium intermediate is reported. The yields ranged from moderate to good.

Theoretical study on the rearrangement of metallabenzenes to cyclopentadienyl complexes

Co-reporter:Chuan Shi, Tongxun Guo, Ka Chun Poon, Zhenyang Lin and Guochen Jia

Dalton Transactions 2011 vol. 40(Issue 42) pp:11315-11320

Publication Date(Web):18 Aug 2011

DOI:10.1039/C1DT10535C

The thermodynamic and kinetic aspects of the rearrangement reactions of a series of metallabenzenes to cyclopentadienyl complexes have been investigated by DFT computational study in order to reveal how substituents on the metallacycle, ligands around the metal center, and metals affect the transformation. We found that substitutents and their locations on the metallacycle have a significant effect on the thermodynamics and kinetics of the rearrangement reactions.

Synthesis and Characterization of a Rhenabenzyne Complex

Co-reporter:Dr. Jiangxi Chen;Dr. Herman H. Y. Sung;Dr. Ian D. Williams;Dr. Zhenyang Lin;Dr. Guochen Jia

Angewandte Chemie 2011 Volume 123( Issue 45) pp:10863-10866

Publication Date(Web):

DOI:10.1002/ange.201104587

Ruthenium-Catalyzed Regioselective Deuteration of Alcohols at the -Carbon Position with Deuterium Oxide

Co-reporter:Dr. Sunny Kai San Tse;Dr. Peng Xue;Christy Wai Sum Lau;Dr. Herman H. Y. Sung; Ian D. Williams ; Guochen Jia

Chemistry - A European Journal 2011 Volume 17( Issue 49) pp:13918-13925

Publication Date(Web):

DOI:10.1002/chem.201101542

Abstract

A convenient method for regioselective H/D exchange between D₂O and alcohols at the β-carbon position using the catalytic system [(p-cymene)RuCl₂]/ethanolamine/KOH is described. This method is applicable for deuteration of both primary and secondary alcohols. The H/D exchange reactions proceed through an oxidation/modification/reduction reaction sequence. Alcohols are first temporarily oxidized to carbonyl compounds by the hydrogen transfer catalyst. The carbonyl compounds then undergo deuteration at the carbon adjacent to the carbonyl group by keto–enol tautomerization in the presence of D₂O and a catalytic amount of base. The deuterated carbonyl compounds are then reduced to produce deuterated alcohols. In support of the reaction mechanism, a well-defined bimetallic ruthenium complex was isolated from the reaction of [{(p-cymene)RuCl₂}₂] with ethanolamine. The activity of this complex is similar to that of [{(p-cymene)RuCl₂}₂]/ethanolamine.

Synthesis and Characterization of a Rhenabenzyne Complex

Co-reporter:Dr. Jiangxi Chen;Dr. Herman H. Y. Sung;Dr. Ian D. Williams;Dr. Zhenyang Lin;Dr. Guochen Jia

Angewandte Chemie International Edition 2011 Volume 50( Issue 45) pp:10675-10678

Publication Date(Web):

DOI:10.1002/anie.201104587

Hydrolysis of Osmium and Ruthenium Carbyne Complexes

Co-reporter:Jiangxi Chen, Herman Ho-Yung Sung, Ian Duncan Williams, and Guochen Jia

Organometallics 2011 Volume 30(Issue 22) pp:6159-6165

Publication Date(Web):November 3, 2011

DOI:10.1021/om200685v

Hydrolysis reactions of MCl3(≡CCH═C(ArCl)2)(PPh3)2 (M = Ru, Os) were investigated. Treatment of OsCl3(≡CCH═C(o,o′-C6H3Cl2)2)(PPh3)2 with water produced the six-membered metallacycle OsCl(κC,κCl-CH═C(o,o′-C6H3Cl2)2)(CO)(PPh3)2. Reactions of MCl3(≡CCH═C(o-C6H4Cl)2)(PPh3)2 (M = Ru, Os) produced the related six-membered metallacycles MCl(κC,κCl-CH═C(o-C6H4Cl)2)(CO)(PPh3)2.

Mechanism Investigations of the Endo Cycloisomerization of Alkynols through Isolation and Characterization of Ruthenium Complexes from the Reactions of Alkynes with a Ruthenium Complex

Co-reporter:Pei Nian Liu, Ting Bin Wen, Kun Dong Ju, Herman H.-Y. Sung, Ian D. Williams, and Guochen Jia

Organometallics 2011 Volume 30(Issue 9) pp:2571-2580

Publication Date(Web):April 5, 2011

DOI:10.1021/om2001684

In our efforts to probe the reaction mechanism of the endo cycloisomerization of alkynols catalyzed by the complex [Ru(N3P)(OAc)](BPh4) (1; NP3 = N,N-bis[(pyridin-2-yl)methyl][2-(diphenylphosphino)phenyl]methanamine), the reactions of 1 with alkynes were investigated. Several complexes related to intermediates in the catalytic reactions were isolated and characterized. In the presence of DIPEA (N,N-diisopropylethanamine), complex 1 reacted with 3-butyn-1-ol to afford the Ru−oxocyclocarbene complex {Ru(N3P)[═C(CH2)3O](OAc)}(BPh4) (4). Under anhydrous conditions, the reaction of complex 1 with tert-butylacetylene afforded [Ru(N3P)(η3-tBuC≡CC═CHBut)](BPh4) (8). In the presence of water, the reaction of complex 1 with tert-butylacetylene afforded [Ru(N3P)(CO)(η1-CH2But)](BPh4) (13). All the reactions are likely to proceed through ruthenium vinylidene intermediates. These results support that ruthenium vinylidene complexes are involved as the key intermediates in the cycloisomerization of alkynols catalyzed by complex 1.

Conversion of Metallabenzynes into Carbene Complexes

Co-reporter:Dr. Jiangxi Chen;Chuan Shi;Dr. Herman H. Y. Sung;Dr. Ian D. Williams;Dr. Zhenyang Lin;Dr. Guochen Jia

Angewandte Chemie International Edition 2011 Volume 50( Issue 32) pp:7295-7299

Publication Date(Web):

DOI:10.1002/anie.201101844

Hydrogen/Deuterium Exchange Reactions of Olefins with Deuterium Oxide Mediated by the Carbonylchlorohydrido- tris(triphenylphosphine)ruthenium(II) Complex

Co-reporter:Sunny Kai San Tse;Peng Xue;Zhenyang Lin

Advanced Synthesis & Catalysis 2010 Volume 352( Issue 9) pp:1512-1522

Publication Date(Web):

DOI:10.1002/adsc.201000037

Abstract

The catalytic properties of several ruthenium, osmium and rhodium hydride complexes for hydrogen/deuterium (H/D) exchange between olefins and deuterium oxide (D₂O) were investigated. The most effective catalytic precursor was found to be the carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) complex. Through H/D exchange between metal hydride and D₂O, and reversible olefin insertion into an RuH(D) bond, protons attached to olefinic carbons and alkyl chains of olefins can all undergo H/D exchange with D₂O. The catalytic reactions can be used to deuterate both terminal and internal olefins, for example, styrene, stilbene and cyclooctene.

Selective and Efficient Cycloisomerization of Alkynols Catalyzed by a New Ruthenium Complex with a Tetradentate NitrogenPhosphorus Mixed Ligand

Co-reporter:PeiNian Liu Dr.;FuHai Su Dr.;TingBin Wen Dr.;HermanH.-Y. Sung Dr.;IanD. Williams Dr. Dr.

Chemistry - A European Journal 2010 Volume 16( Issue 26) pp:7889-7897

Publication Date(Web):

DOI:10.1002/chem.200903441

Abstract

The new ruthenium complex [Ru(N₃P)(OAc)][BPh₄] (4), in which N₃P is the N,P mixed tetradentate ligand N,N-bis[(pyridin-2-yl)methyl]-[2-(diphenylphosphino)phenyl]methanamine was synthesized. The complex was found to be catalytically active for the endo cycloisomerization of alkynols. The catalytic reactions can be used to synthesize five-, six-, and seven-membered endo-cyclic enol ethers in good to excellent yields. A catalytic cycle involving a vinylidene intermediate was proposed for the catalytic reactions. Treatment of complex 4 with PhCCH and H₂O gave the alkyl complex [Ru(CH₂Ph)(CO)(N₃P)][BPh₄] (30), which supports the assumption that the catalytic reactions involve addition of a hydroxyl group to the CC bond of vinylidene ligands.

Synthesis and Characterization of Rhenabenzenes

Co-reporter:KaChun Poon;Liangxian Liu Dr.;Tongxun Guo;Juan Li Dr.;HermanH.Y. Sung Dr.;IanD. Williams Dr.;Zhenyang Lin Dr. Dr.

Angewandte Chemie International Edition 2010 Volume 49( Issue 15) pp:2759-2762

Publication Date(Web):

DOI:10.1002/anie.200907014

Substituted Cyclopentadienyl Osmium Complexes from the Reactions of OsH3Cl(PPh3)3 with Fulvenes and Cyclopentadienes

Co-reporter:Sunny Kai San Tse, Wei Bai, Herman Ho-Yung Sung, Ian Duncan Williams and Guochen Jia

Organometallics 2010 Volume 29(Issue 16) pp:3571-3581

Publication Date(Web):July 15, 2010

DOI:10.1021/om1005066

Two methodologies were developed for the preparation of half-sandwich osmium complexes with the general formula (η5-cyclopentadienyl)OsCl(PPh3)2. The first approach involves the reactions of OsH3Cl(PPh3)3 with cyclopentadienes. Treatment of OsH3Cl(PPh3)3 with cyclopentadienes gives (η5-cyclopentadienyl)OsCl(PPh3)2 via C−H oxidative addition of cyclopentadienes followed by reductive elimination of hydrogen. The methodology has enabled us to synthesize a series of half-sandwich osmium complexes containing Cp, Cp*, indenyl, and C5Me4R (R = H, Et, n-Pr). The second approach involves the insertion reactions of OsH3Cl(PPh3)3 with fulvenes. Treatment of OsH3Cl(PPh3)3 with C6-substituted fulvenes produces cleanly monosubstituted cyclopentadienyl osmium complexes (η5-C5H4CHRR′)OsCl(PPh3)2 (R = H, R′ = p-C6H4CH3, p-C6H4OCH3, CMe3; R = R′ = Ph) via hydride transfer to the electrophilic exocyclic carbon of fulvenes. Under similar conditions, OsH3Cl(PPh3)3 reacts with C6-monosubstituted 1,2,3,4-tetramethylfulvenes to give pentasubstituted cyclopentadienyl osmium complexes (η5-C5Me4CH2R)OsCl(PPh3)2 (R = p-C6H4CH3, p-C6H4OCH3, pyrenyl).

Rhenium Carbyne and η2-Vinyl Complexes from One-Pot Reactions of ReH5(PMe2Ph)3 with Terminal Alkynes

Co-reporter:Jiangxi Chen, Guomei He, Herman Ho-Yung Sung, Ian Duncan Williams, Zhenyang Lin and Guochen Jia

Organometallics 2010 Volume 29(Issue 12) pp:2693-2701

Publication Date(Web):May 25, 2010

DOI:10.1021/om100122a

Treatment of the rhenium polyhydride complex ReH5(PMe2Ph)3 with HC≡CR (R = Ph, SiMe3, (CH2)4Me) in the presence of 2.2 equiv of HCl produces a mixture of the carbyne complexes Re(≡CCH2R)Cl2(PMe2Ph)3 and the η2-vinyl complexes Re(η2-CH2CR)Cl2(PMe2Ph)3. When HC≡CC(OH)Ph2 was used, the reaction gave the carbyne complexes Re(≡CCH═CPh2)Cl2(PMe2Ph)3 and Re(≡CCH2C(OH)Ph2)Cl2(PMe2Ph)3 along with the η2-vinyl complex Re(η2-CH2CC(OH)Ph2)Cl2(PMe2Ph)3.

Insertion reactions of allenes with transition metal complexes

Co-reporter:Tao Bai, Shengming Ma, Guochen Jia

Coordination Chemistry Reviews 2009 Volume 253(3–4) pp:423-448

Publication Date(Web):February 2009

DOI:10.1016/j.ccr.2008.04.003

Recently, allenes have been widely used as starting materials to synthesize various organic compounds and polymeric materials, especially through reactions catalyzed by transition metal catalysts. In many of the catalytic reactions, insertion of allenes is one of the most important elementary steps. In this review, stoichiometric insertion reactions of transition metal complexes with allenes affording well-defined inserted products are summarized, which may help chemists to understand the mechanisms of catalytic reactions of allenes and to design new catalytic reactions of allenes.

Synthesis of Monosubstituted Cyclopentadienyl Ruthenium Complexes from the Reactions of 6-Substituted Fulvenes with RuHCl(PPh3)3

Co-reporter:Sunny Kai San Tse, Tongxun Guo, Herman Ho-Yung Sung, Ian Duncan Williams, Zhenyang Lin and Guochen Jia

Organometallics 2009 Volume 28(Issue 18) pp:5529-5535

Publication Date(Web):August 6, 2009

DOI:10.1021/om900527v

Reactions between 6-substitued fulvenes and the hydride complex RuHCl(PPh3)3 are described. Treatment of RuHCl(PPh3)3 with fulvenes without sp3-CH protons at the carbon α to the exocyclic carbon of fulvene produces cleanly monosubstituted cyclopentadienyl ruthenium complexes (η5-C5H4R)RuCl(PPh3)2 via hydride transfer to the electrophilic exocyclic carbon of fulvenes. When fulvenes containing sp3-CH protons at the carbon α to the exocyclic carbon were used, the reactions produce the expected (η5-C5H4R)RuCl(PPh3)2 complexes along with minor amounts of vinylcyclopentadienyl ruthenium complexes due to dehydrogenation.

O-Abstraction Reactions of Nitrous Oxide with Cp2Ti(II) and Other Middle Transition Metal Complexes

Co-reporter:Haizhu Yu, Guochen Jia and Zhenyang Lin

Organometallics 2009 Volume 28(Issue 4) pp:1158-1164

Publication Date(Web):January 29, 2009

DOI:10.1021/om800897s

DFT calculations have been carried out to study the detailed mechanisms of the O-abstraction reaction of N2O with Cp2Ti(II). The reaction is initiated by coordination of N2O to Cp2Ti via the N-end to form a linear N2O-coordinated species Cp2Ti(N2O), from which the metal center transfers one of its metal d electrons to one π* orbital of the N2O ligand and gives a bent N2O-coordinated intermediate Cp2Ti←N═N−O. The intermediate then reacts barrierlessly with another molecule of Cp2Ti to form an N2O-bridged intermediate Cp2Ti←N═N−O−TiCp2, from which the singly oxo-bridged product (Cp2Ti)2O is formed with a release of N2. Reactions of N2O with other middle transition metal complexes have also been calculated and discussed. General mechanisms for O-abstraction reactions of N2O with early and middle transition metal complexes have been provided.

Ruthenium-Catalyzed Intramolecular Amination Reactions of Aryl- and Vinylazides

Co-reporter:Wang Ge Shou, Juan Li, Tongxun Guo, Zhenyang Lin and Guochen Jia

Organometallics 2009 Volume 28(Issue 24) pp:6847-6854

Publication Date(Web):November 24, 2009

DOI:10.1021/om900275j

The catalytic activity of a series of ruthenium complexes for C−H amination reactions of organic azides was investigated. The most active catalyst was found to be RuCl3, which promotes C−H amination reactions of ortho-aryl phenylazides, 1-azido-2-arylvinylazides, and 1-azido-1,3-butadienes to give carbazoles, indoles, and pyrroles, respectively. Both computational and experimental results support that a two-step process involving formal electrocyclization is involved in the catalytic reaction.

An efficient synthesis of 2-vinylic cyclic 1,3-alkadienes via the Cp*Ru(II)-catalyzed intermolecular coupling reactions of alkynes and cyclic allenes

Co-reporter:Tao Bai, Peng Xue, Li Zhang, Shengming Ma and Guochen Jia

Chemical Communications 2008 (Issue 25) pp:2929-2931

Publication Date(Web):16 Apr 2008

DOI:10.1039/B801500G

2-Vinylic cyclic 1,3-alkadienes can be obtained with moderate to good yields via the Cp*RuCl(PPh3)2-catalyzed coupling reaction of alkynes with cyclic allenes.

Theoretical Studies on O-Insertion Reactions of Nitrous Oxide with Ruthenium Hydride Complexes

Co-reporter:Haizhu Yu ; Guochen Jia ;Zhenyang Lin

Organometallics 2008 Volume 27(Issue 15) pp:3825-3833

Publication Date(Web):July 1, 2008

DOI:10.1021/om8000845

DFT calculations have been carried out to study the mechanism of the N2O O-insertion into the Ru−H bonds of ruthenium hydride complexes (dmpe)2Ru(H)(X) (X = OH, H). The reaction pathways for the formation of the monoinsertion product (dmpe)2Ru(H)(OH) and the bis(hydroxo) complex (dmpe)2Ru(OH)(OH), which were obtained directly from the reactions of N2O with the ruthenium hydride complexes, have been investigated in detail. Focus has been made to understand how the kinetically inert N2O is activated by the hydride complexes. It is found that N2O is activated through the hydride ligand nucleophilically attacking the terminal nitrogen of N2O followed by coordination of the activated N2O via the O-end.

Reactions of Cp*RuCl(COD) with Alkynes: Isolation of Dinuclear Metallacyclopentatriene Complexes

Co-reporter:Li Zhang ; Herman Ho-Yung Sung ; Ian Duncan Williams ; Zhenyang Lin

Organometallics 2008 Volume 27(Issue 19) pp:5122-5129

Publication Date(Web):September 4, 2008

DOI:10.1021/om8002202

The reactions of Cp*RuCl(COD) with alkynes in different solvents were investigated. Treatment of Cp*RuCl(COD) with phenylacetylene in benzene or dichloromethane gives the ruthenacyclopentatriene complex Cp*RuCl(2,5-Ph2C4H2) and free COD. In methanol, a formal [2+2+2] cycloaddition of the COD ligand with PhC≡CH occurred and the reaction produces a tricyclo[4.2.2.02,5]dec-7-ene (C6H5-C10H13) and its complex [Cp*Ru(η6-C6H5-C10H13)]Cl along with the dinuclear ruthenacyclopentatriene complex [Cp*RuCl(η2,η4,μ-2,5-Ph2C4H2)RuCp*]Cl. 3-Hexyne was found to be unreactive toward Cp*RuCl(COD) in benzene or dichloromethane at room temperature. In methanol, it reacts with Cp*RuCl(COD) to give a tricyclo[4.2.2.02,5]dec-7-ene (Et2-C10H12) and the dinuclear ruthenacyclopentatriene complex [Cp*RuCl(η2,η4,μ-C4Et4)RuCp*]Cl. 1-Hexyne was found to react with Cp*RuCl(COD) in C6D6, CD2Cl2, and diethyl ether to give the neutral dinuclear ruthenacyclopentadiene complex Cp*RuCl2(η2,η4,μ-C4H2Bu2)RuCp* along with free COD, while in methanol it gives a tricyclo[4.2.2.02,5]dec-7-ene (Bu-C10H13) and Cp*RuCl2(η2,η4,μ-C4H2Bu2)RuCp*.

Theoretical Studies on Coupling Reactions of Carbon Dioxide with Alkynes Mediated by Nickel(0) Complexes

Co-reporter:Juan Li ; Guochen Jia ;Zhenyang Lin

Organometallics 2008 Volume 27(Issue 15) pp:3892-3900

Publication Date(Web):July 15, 2008

DOI:10.1021/om8002224

A computational study with the Becke3LYP DFT functional theory was carried out on Ni(0)-mediated coupling reactions of both terminal and internal alkynes with CO2. We studied the mechanism for the formation of the five-membered metallacyclic intermediates in order to understand the regioselectivity. The steric and electronic factors that determine the regioselectivity have been discussed. The calculations indicate that electronic factors nicely explain the trend observed in the barriers calculated for the coupling reactions of CO2 with the three terminal alkyne substrates having substituents with different electronic properties, but steric factors are dominant in the regioselectivity for the reaction of a given terminal alkyne substrate. For silyl-substituted internal alkynes, both electronic and steric effects favor the formation of compounds in which CO2 couples with the silyl-substituted carbon.

Insertion Reactions of Allenes with Palladium Aryl Complexes [PdI(Ph)(PPh3)]2 and PdI(Ph)(dppe)

Co-reporter:Tao Bai, Liqin Xue, Peng Xue, Jun Zhu, Herman Ho-Yung Sung, Shengming Ma, Ian Duncan Wiliams, Zhenyang Lin and Guochen Jia

Organometallics 2008 Volume 27(Issue 11) pp:2614-2626

Publication Date(Web):May 3, 2008

DOI:10.1021/om800030a

Treatment of [PdI(Ph)(PPh3)]2 with allenes CH2═C═CHR (R = CMe3, CO2Et, P(O)(OEt)2, and SO2Ph) in dichloromethane at room temperature produces a mixture of cis and trans isomers of the π-allyl palladium complexes PdI(η3-CH2C(Ph)CHR)(PPh3) in which the R group is anti to the Ph group. The disubstituted allenes MeCH═C═CHR (R = P(O)(OEt)2 and SO2Ph) similarly react with [PdI(Ph)(PPh3)]2 to give the π-allyl palladium complexes PdI(η3-MeCHC(Ph)CHR)(PPh3) in which the R group is anti and the Me group is syn to the Ph group. PdI(Ph)(dppe) alone was found to be unreactive toward allenes such as CH2═C═CHSO2Ph and MeCH═C═CHSO2Ph at room temperature. In contrast, in the presence of TlPF6, PdI(Ph)(dppe) readily reacts with allenes CH2═C═CHR (R = CMe3, CO2Et, COPh, and SO2Ph) and MeCH═C═CHSO2Ph to give the π-allyl palladium complexes [Pd(η3-CH2C(Ph)CHR)(dppe)]PF6 and [Pd(η3-MeCHC(Ph)CHR)(dppe)]PF6, respectively. Although mechanistically possible, vinyl complexes were not observed as the insertion products in all cases. The substituents of allenes appear to have no effect on the reaction pathways, at least for the allenes used in this study. The insertion reactions involving PdI(Ph)(PR3)(allene) have been studied by computational chemistry using the model complex PdI(Ph)(MeCH═C═CHSO2H)(PH3).

Coupling Reactions of an Allenylcarbene Complex with Alkynes and Styrene

Co-reporter:Ting Bin Wen;Wai Yiu Hung;Herman H.-Y. Sung;Zhongyuan Zhou;Ian D. Williams

European Journal of Inorganic Chemistry 2007 Volume 2007(Issue 18) pp:

Publication Date(Web):23 APR 2007

DOI:10.1002/ejic.200601251

The allenylcarbene complex [OsCl₂{=CPh(η²-CH=C=CHPh)}(PPh₃)₂] undergoes coupling reactions with HC≡CSiMe₃ and PhC≡CC≡CPh to produce the fulvene complexes [OsCl₂{η⁶-C₅H₂(Ph)(SiMe₃)(=CHPh)}(PPh₃)] and [OsCl₂{η⁶-C₅H(Ph)₂(C≡CPh)(=CHPh)}(PPh₃)], respectively. A similar coupling reaction also occurs between [OsCl₂{=CPh(η²-CH=C=CHPh)}(PPh₃)₂] and styrene.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

A Metallanaphthalyne Complex from Zinc Reduction of a Vinylcarbyne Complex

Co-reporter:Guomei He;Jun Zhu;Wai Yiu Hung Dr.;Ting Bin Wen Dr.;Herman Ho-Yung Sung Dr.;Ian Duncan Williams Dr.;Zhenyang Lin Dr. Dr.

Angewandte Chemie 2007 Volume 119(Issue 47) pp:

Publication Date(Web):24 OCT 2007

DOI:10.1002/ange.200703289

Cl verhindert Insertion: Das erste Metalladehydronaphthalin, 2, wurde durch zinkvermittelte Reduktion des Osmium-Carbinkomplexes 1 erhalten. Entscheidend war die Verwendung von o-Chlorphenyl- anstelle von Phenylsubstituenten, da so die nach DFT-Rechnungen erwartete Bildung eines Hydrido-Metalladehydronaphthalins vermieden wurde. Ein solches Intermediat würde durch migratorische Insertion des Carbins in die Os-H-Bindung und anschließende Umlagerung einen Indenylliganden als Endprodukt liefern.

DFT Studies on the Mechanism of Reactions between N2O and Cp2M(η2-alkyne) (M = Ti, Zr)

Co-reporter:Haizhu Yu, Guochen Jia and Zhenyang Lin

Organometallics 2007 Volume 26(Issue 27) pp:6769-6777

Publication Date(Web):December 7, 2007

DOI:10.1021/om7010134

DFT calculations have been carried out to study the activation of N2O by the transition-metal alkyne complexes Cp2M(η2-alkyne) (M = Ti, Zr). The mechanism for the formation of the five-membered metallacyclic complexes Cp2M(RC═CR′NN(O)), which were obtained directly from the reactions of N2O with the metal alkyne complexes, and the conversion of the five-membered metallacyclic complexes Cp2M(RC═CR′NN(O)) via N2 loss to the oxametallacyclobutene complexes Cp2M(RC═CR′O) have been investigated in detail. An effort has been made to understand how the kinetically inert N2O can be activated. We concluded that N2O is best activated by metal fragments that possess high capability of π-back-bonding interactions with the π* orbitals of N2O.

A Metallanaphthalyne Complex from Zinc Reduction of a Vinylcarbyne Complex

Co-reporter:Guomei He;Jun Zhu;Wai Yiu Hung Dr.;Ting Bin Wen Dr.;Herman Ho-Yung Sung Dr.;Ian Duncan Williams Dr.;Zhenyang Lin Dr. Dr.

Angewandte Chemie International Edition 2007 Volume 46(Issue 47) pp:

Publication Date(Web):24 OCT 2007

DOI:10.1002/anie.200703289

Cl prevents insertion: The first metallanaphthalyne 2 has been obtained by Zn reduction of Os carbyne complex 1. The key to its isolation was the use of o-chlorophenyl instead of phenyl substituents to avoid formation of a putative hydrido metallanaphthalyne intermediate (supported by DFT calculations), which undergoes migratory insertion of the carbyne into the OsH bond and rearrangement to give an indenyl complex as the final product.

Osmium-Mediated Hexamerization of Phenylacetylene

Co-reporter:Ting Bin Wen Dr.;Zhong Yuan Zhou Dr.

Angewandte Chemie 2006 Volume 118(Issue 35) pp:

Publication Date(Web):31 JUL 2006

DOI:10.1002/ange.200601542

Größer als übliche Oligomere: Übergangsmetallkatalysierte Reaktionen von Alkinen zu Dimeren, Trimeren, Tetrameren und Polymeren sind reichlich bekannt, Umsetzungen von Alkinen zu definierten Oligomeren mittleren Molekulargewichts (Pentameren, Hexameren) hingegen kaum. Die selektive Hexamerisierung von HCCPh bei der Reaktion mit [OsCl(PCP)(PPh₃)] (PCP=2,6-(Ph₂PCH₂)₂C₆H₃; siehe Schema) ist ein seltenes Beispiel dafür.

Synthesis and Characterization of Stable Ruthenabenzenes

Co-reporter:Hong Zhang;Haiping Xia Dr.;Guomei He;Ting Bin Wen Dr.;Lei Gong Dr.

Angewandte Chemie 2006 Volume 118(Issue 18) pp:

Publication Date(Web):27 MAR 2006

DOI:10.1002/ange.200600055

Eine seltene Spezies: Während viele stabile Metallabenzolderivate mit einem Metallatom aus der dritten Übergangsmetallreihe bekannt sind, gibt es nur wenige mit einem Metallatom aus der ersten oder zweiten Übergangsmetallreihe. Hier wird die Synthese und Charakterisierung luftstabiler Ruthenabenzole (z. B. 1 und 2) vorgestellt.

Synthesis and Characterization of Stable Ruthenabenzenes

Co-reporter:Hong Zhang;Haiping Xia Dr.;Guomei He;Ting Bin Wen Dr.;Lei Gong Dr.

Angewandte Chemie International Edition 2006 Volume 45(Issue 18) pp:

Publication Date(Web):27 MAR 2006

DOI:10.1002/anie.200600055

A rare breed: Although many stable metallabenzene derivatives with a metal atom from the third transition series are known, those with a metal atom from the first and the second transition series are rare. Air-stable ruthenabenzenes (e.g. 1 and 2) have now been isolated and characterized.

Osmium-Mediated Hexamerization of Phenylacetylene

Co-reporter:Ting Bin Wen Dr.;Zhong Yuan Zhou Dr.

Angewandte Chemie International Edition 2006 Volume 45(Issue 35) pp:

Publication Date(Web):31 JUL 2006

DOI:10.1002/anie.200601542

A larger oligomer: Although transition-metal-mediated reactions of alkynes to give dimers, trimers, tetramers, and polymers are well-known, reactions of alkynes to give well-defined oligomers of medium molecular weight (e.g. pentamers, hexamers) are very scarce. The selective hexamerization of HCCPh in the reaction with [OsCl(PCP)(PPh₃)] (PCP=2,6-(Ph₂PCH₂)₂C₆H₃; see scheme) is a rare example thereof.

A Neutron Diffraction Study of [OsClH3(PPh3)3]: A Complex Containing a Highly “Stretched” Dihydrogen Ligand

Co-reporter:Muhammed Yousufuddin;Ting Bin Wen Dr.;Sax A. Mason Dr.;Garry J. McIntyre Dr. Dr.;Robert Bau Dr.

Angewandte Chemie 2005 Volume 117(Issue 44) pp:

Publication Date(Web):17 OCT 2005

DOI:10.1002/ange.200502297

Elastische Bindungen: Die Struktur von [OsClH(η²-H₂)(PPh₃)₃] wurde durch Neutronenbeugung bestimmt (siehe Bild). Mit einem ungewöhlichen H⋅⋅⋅H-Kontakt von 1.48(2) Å kann die Verbindung als stark gedehnter Diwasserstoffkomplex oder als komprimierter Dihydridkomplex angesehen werden.

A Neutron Diffraction Study of [OsClH3

Co-reporter:Muhammed Yousufuddin, Ting Bin Wen, Sax A. Mason, Garry J. McIntyre, Guochen Jia,Robert Bau

Angewandte Chemie International Edition 2005 44(44) pp:7227-7230

Publication Date(Web):

DOI:10.1002/anie.200502297

Theoretical Studies on the Metathesis Processes, [Tp(PH3)MR(η2-HCH3)] [Tp(PH3)M(CH3)(η2-HR)] (M=Fe, Ru, and Os; R=H and CH3)

Co-reporter:Wai Han Lam ;Zhenyang Lin ;Chak Po Lau ;Odile Eisenstein

Chemistry - A European Journal 2003 Volume 9(Issue 12) pp:

Publication Date(Web):6 JUN 2003

DOI:10.1002/chem.200204570

Theoretical calculations on the metathesis process, [Tp(PH₃)MR(η²-HCH₃)] [Tp(PH₃)M(CH₃)(η²-HR)] (M=Fe, Ru, and Os; R=H and CH₃), have been systematically carried out to study their detailed reaction mechanisms. Other than the one-step mechanism via a four-center transition state and the two-step mechanism through an oxidative addition/reductive elimination pathway, a new one-step mechanism, with a transition state formed under oxidative addition, has been found. Based on the intrinsic reaction coordinate calculations, we found that the trajectories of the transferring hydrogen atom in the metathesis processes studied are similar to each other regardless of the nature of reaction mechanisms.

A Triple-Decker Complex with a Central Metallabenzene

Co-reporter:Sheng Hua Liu Dr.;Weng Sang Ng Dr.;Hei Shing Chu Dr.;Ting Bin Wen;Haiping Xia;Zhong Yuan Zhou ;Chak Po Lau

Angewandte Chemie International Edition 2002 Volume 41(Issue 9) pp:

Publication Date(Web):2 MAY 2002

DOI:10.1002/1521-3773(20020503)41:9<1589::AID-ANIE1589>3.0.CO;2-4

Although their existence was suggested eight years ago, triple-decker complexes with a central metallabenzene have not been synthesized before. The ruthenabenzene-bridged complex 1 appears to be the first well-characterized example of a complex of this type with a bridging metallabenzene. The unusual central ligand was formed from coordinated norbornadiene via vinylcyclopentadiene.

Theoretical study on the rearrangement of metallabenzenes to cyclopentadienyl complexes

Co-reporter:Chuan Shi, Tongxun Guo, Ka Chun Poon, Zhenyang Lin and Guochen Jia

Dalton Transactions 2011 - vol. 40(Issue 42) pp:NaN11320-11320

Publication Date(Web):2011/08/18

DOI:10.1039/C1DT10535C

An efficient synthesis of 2-vinylic cyclic 1,3-alkadienes via the Cp*Ru(II)-catalyzed intermolecular coupling reactions of alkynes and cyclic allenes

Co-reporter:Tao Bai, Peng Xue, Li Zhang, Shengming Ma and Guochen Jia

Chemical Communications 2008(Issue 25) pp:NaN2931-2931

Publication Date(Web):2008/04/16

DOI:10.1039/B801500G

2-Vinylic cyclic 1,3-alkadienes can be obtained with moderate to good yields via the Cp*RuCl(PPh3)2-catalyzed coupling reaction of alkynes with cyclic allenes.

Phosphine-catalyzed cage carbon functionalization of o-carborane: facile synthesis of alkenylcarboranes

Co-reporter:Fangrui Zheng, Tsz-Fai Leung, Ka-Wing Chan, Herman H. Y. Sung, Ian D. Williams, Zuowei Xie and Guochen Jia

Chemical Communications 2016 - vol. 52(Issue 71) pp:NaN10770-10770

Publication Date(Web):2016/08/02

DOI:10.1039/C6CC05283E

A phosphine-catalyzed alkenylation reaction of o-carborane with electron-deficient alkynes at the C–H vertex of the o-carborane cage has been developed, which led to the preparation of a series of 1-alkenyl-o-carboranes in moderate to very good yields with excellent regio- and stereoselectivity. This highly efficient and simple method represents the first example of organophosphine catalyzed C–H functionalization of o-carborane.