@article { ISI:000351442700019, title = {A New Side-on End-On Ditantalum Dinitrogen Complex and Its Reaction with BuSiH3}, journal = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, volume = {641}, number = {1, SI}, year = {2015}, month = {JAN}, pages = {123-127}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

The formation of the P-cyclohexyl dinitrogen complex, (CyPh{[}NPN]Ta)(2)(mu-eta(2):eta(1)-N-2)(mu-H)(2) ((CyPh){[}NPN] = {[}CyP(CH2SiMe2NPh)(2)], and Cy = C6H11) is described and its reaction with butylsilane (BuSiH3) explored. The reaction was monitored by multinuclear NMR spectroscopy and showed the formation of a number of intermediates. The final product is a hydride-bridged imidoamido silyated species that has the imido bridging between the two central tantalum atoms. The origin of the bridging hydrides in the product is likely to arise from the excess silane present, on the basis of labeling studies.

}, keywords = {DINITROGEN, DINUCLEAR, Hydride route, HYDROSILYLATION, tantalum}, issn = {0044-2313}, doi = {10.1002/zaac.201400167}, author = {Yeo, Alyssa and Shaver, Michael P. and Fryzuk, Michael D.} } @article {2629, title = {Rhodium(I)-(N-heterocyclic carbene)-diphosphine complexes}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {87}, number = {9}, year = {2009}, note = {ISI Document Delivery No.: 493QBTimes Cited: 0Cited Reference Count: 45Sun, Hongsui Yu, Xiao-Yan Marcazzan, Paolo Patrick, Brian O. James, Brian R.}, month = {Sep}, pages = {1248-1254}, type = {Article}, abstract = {{Les reactions du [RhCl(COE)(IPr)](2) (1) et du [RhCl(COE)(IMes)](2) (2) [COE = cyclooctene; IPr = N,N{\textquoteright}-bis(2,6-diisopropylphenyl)imidazoline-2-ylidene; IMes = N,N{\textquoteright}-bis(2,4,6-trimethylphenyl)imidazoline-2-ylidene] avec les diphosphines Ph2P(CH2)(n)PPh2 et 1,2-bis(diphenylphosphino)benzene (dppbz) conduisent a la formation de complexes carbene N-heterocyclique (NHC) - diphosphine - rhodium(I): RhCl(NHC)[Ph2P(CH2)(n)PPh2] [NHC = IPr}, keywords = {C-H ACTIVATION, CATALYTIC-ACTIVITY, HETEROCYCLIC CARBENE COMPLEXES, HYDROFORMYLATION, HYDROGENATION REACTIONS, HYDROSILYLATION, iridium complexes, LIGANDS, phosphine, RHODIUM(I) COMPLEXES}, isbn = {0008-4042}, url = {://000269751100008}, author = {Sun, H. S. and Yu, X. Y. and Marcazzan, P. and Patrick, B. O. and James, Brian R.} } @article {23411, title = {Side-on End-on Bound Dinitrogen: An Activated Bonding Mode That Facilitates Functionalizing Molecular Nitrogen}, journal = {Accounts of Chemical Research}, volume = {42}, year = {2009}, month = {Jan}, pages = {127-133}, type = {Review}, abstract = {

Molecular nitrogen is the source of all of the nitrogen necessary to sustain life on this planet. How it is incorporated into the biosphere is complicated by its intrinsic inertness. For example, biological nitrogen fixation takes N-2 and converts it into ammonia using various nitrogenase enzymes, whereas industrial nitrogen fixation converts N-2 and H-2 to NH3 using heterogeneous iron or ruthenium surfaces. In both cases, the processes are energy-intensive. Is it possible to discover a homogeneous catalyst that can convert molecular nitrogen into higher-value organonitrogen compounds using a less energy-intensive pathway? If this could be achieved, it would be considered a major breakthrough in this area. In contrast to carbon monoxide, which is reactive and an important feedstock in many homogeneous catalytic reactions, the ischelectronic but inert N-2 molecule is a very poor ligand and not a common industrial feedstock, except for the above-mentioned industrial production of NH3. Because N-2 is readily available from the atmosphere and because nitrogen is an essential element for the biosphere, attempts to discover new processes involving this simple small molecule have occupied chemists for over a century. Since the first discovery of a dinitrogen complex in 1965, inorganic chemists have been key players in this area and have contributed much fundamental knowledge on structures, binding modes, and reactivity patterns. For the most part, the synthesis of dinitrogen complexes relies on the use of reducing agents to generate an electron-rich intermediate that can interact with this rather inert molecule. In this Account, a facile reaction of dinitrogen with a ditantalum tetrahydride species to generate the unusual side-on end-on bound N-2 moiety is described. This particular process is one of a growing number of new, milder ways to generate dinitrogen complexes. Furthermore, the resulting dinitrogen complex undergoes a number of reactions that expand the known patterns of reactivity for coordinated N-2. This Account reviews the reactions of ([NPN]Ta)(2)(mu-H)(2)(mu-eta(1):eta(2)-N-2), 2 (where NPN = PhP(CH2SiMe2NPh)(2)), with a variety of simple hydride reagents, E-H (where E-H = R2BH, R2AlH, RSiH3, and Cp2ZrCl(H)), each of which results in the cleavage of the N-N bond to form various functionalized imide and nitride moieties. This work is described in the context of a possible catalytic cycle that in principle could generate higher-value nitrogen-containing materials and regenerate the starting ditantalum tetrahydride. How this fails for each particular reagent is discussed and evaluated.

}, keywords = {ammonia, CLEAVAGE, CONVERSION, COORDINATED N-2 LIGAND, H-2, HYDROSILYLATION, MOLYBDENUM, REACTIVITY, REDUCTION, TANTALUM COMPLEX}, isbn = {0001-4842}, author = {Fryzuk, MD} } @article {4651, title = {Dimeric rhodium mu-silylene and mu-eta(2)-silyl complexes: Catalytic silicon-silicon bond formation and x-ray structures of [{Pr(i)(2)PCH2CH2PPr(i)(2)}Rh](2)(mu-SiRR {\textquoteright})(2) (R = R {\textquoteright} = Ph and R = Me, R {\textquoteright} = Ph) and [{Pr(i)(2)PCH2CH2PPr(i)(2)}Rh(H)](2)(}, journal = {Organometallics}, volume = {18}, number = {6}, year = {1999}, note = {ISI Document Delivery No.: 178FRTimes Cited: 29Cited Reference Count: 32}, month = {Mar}, pages = {958-969}, type = {Article}, abstract = {The stoichiometric and catalytic reactions of secondary silanes with the rhodium hydride bridged dimer [(dippe)Rh](2)(mu-H)(2) (1; dippe = 1,2-bis(diisopropylphosphino)ethane) are described. The reaction of 1 with Ph2SiH2 results in the formation of the bis(mu-silylene) complex [(dippe)Rh](2)(mu-SiPh2)(2) (2a); a similar reaction ensues upon addition of MePhSiH2 or Me(p)TolSiH(2) ((P)Tol =p-tolyl) to 1 except that the bis(silylene) complexes exist as a mixture of cis and trans stereoisomers. Dimethylsilane reacts with 1 to generate the dinuclear complex [(dippe)Rh(H)](2)(mu-eta(2)-SiMe2)(2) (4d). The hydride dimer acts as a catalyst precursor for the dimerization of excess Ph2SiH2 to tetraphenyldisilane (Ph2SiHSiHPh2). A catalytic cycle is proposed that consists of dinuclear intermediates.}, keywords = {BONDS, hydride complexes, HYDROSILYLATION, REACTIVITY, SECONDARY SILANES, SI, TRANSITION-METAL COMPLEXES}, isbn = {0276-7333}, url = {://000079256000005}, author = {Rosenberg, L. and Fryzuk,Michael D. and Rettig, S. J.} } @article {3352, title = {CATALYSIS OF HYDROSILYLATION .28. THE ROLE OF DIOXYGEN IN HYDROSILYLATION OF ALKENES CATALYZED BY RUTHENIUM PHOSPHINE COMPLEXES}, journal = {Journal of Organometallic Chemistry}, volume = {499}, number = {1-2}, year = {1995}, note = {ISI Document Delivery No.: RR624Times Cited: 3Cited Reference Count: 24}, month = {Sep}, pages = {173-179}, type = {Article}, abstract = {Catalytic hydrosilylation of C=C bonds in alkenes in the presence of Ru(II)-phosphine complexes takes place only for alkoxy-substituted silanes in the absence of solvent and in the presence of small amounts of O-2. The activation effect of {\textquoteright}{\textquoteright}trace{\textquoteright}{\textquoteright} O-2, noted previously for rhodium and other transition metal phosphine complex catalysts for several catalytic processes, has been little studied to date. In this work, oxygen is considered to cause removal of phosphine as its oxide, formation of intermediate dioxygen complexes (followed by oxygenation of Ru-Si= to an Ru-O-Si= moiety with elimination of disiloxane) and possible formation of Ru(IV) species. The studies include the characterization of isolated intermediates (well defined complexes or their mixtures) from an RuCl2(PPh(3))(3)-HSi(OC2H5)(3) system and general mechanisms for the hydrosilylation of alkenes in the presence of Ru(II) precursors are discussed.}, keywords = {ALKENES, CATALYSIS, CHEMISTRY, DIOXYGEN, HYDROSILYLATION, rhodium, ruthenium, SILANE}, isbn = {0022-328X}, url = {://A1995RR62400025}, author = {Gulinski, J. and James, Brian R. and Marciniec, B.} }