@article {2528, title = {Synthesis and Characterization of a New Thiophene-Bridged Diamidophosphine [NPN] Donor Set and Its Coordination Chemistry with Zirconium(IV): Unexpected Deprotonation-Lithiation Sequence with a Mesitylaminothiophene Precursor}, journal = {Organometallics}, volume = {28}, number = {17}, year = {2009}, note = {ISI Document Delivery No.: 489MMTimes Cited: 1Cited Reference Count: 43Menard, Gabriel Jong, Howard Fryzuk, Michael D.}, month = {Sep}, pages = {5253-5260}, type = {Article}, abstract = {The synthesis and characterization of the thiophene-bridged diamidophosphine proligand [NPN]H-S(2) (2) (where [NPN]H-S(2) = {[N-(2,4,6-Me3C6H2)(3-NH-SC4H2-2-)](2)PPh}) along with several [NPN](ZrX2)-Zr-S (X = NMe2, Cl, I) complexes are presented. The ligand precursor [NPN]H-S(2) was prepared from N-(2,4,6-Me3C6H2)(3-NH-4-Br-SC4H2) (1),(BuLi)-Bu-t, and PhPCl2 in Et2O in 50\% yield; the stereochemistry of the ligand precursor was unexpected and likely resulted from a competitive bromine-lithium exchange and deprotonation sequence with the thiophene starting material I and (BuLi)-Bu-t. A mechanism to rationalize the observed stercochemistry of the product is proposed following deuteration experiments. [NPN]Zr-S(NMe2)(2) (8) can be prepared in 80\% yield by the direct reaction of [NPN]H-S(2) and Zr(NMe2)(4) in toluene. Both [NPN](ZrCl2)-Zr-S (9) and [NPN](ZrI2)-Zr-S (10) are prepared in high yield by the reaction of 8 with excess Me3SiCl or Me3SiI, respectively.}, keywords = {DIARYLAMIDO-PHOSPHINE-LIGANDS, DIRECTED ORTHO-LITHIATION, END-ON, hafnium, HALOGEN EXCHANGE, lithium, METAL-COMPLEXES, MOLECULAR NITROGEN, ON-BOUND DINITROGEN, PALLADIUM-CATALYZED AMINATION, SIDE-ON}, isbn = {0276-7333}, url = {://000269424200046}, author = {Menard, G. and Jong, H. and Fryzuk,Michael D.} } @article {1475, title = {Substituent effects in the hydrosilylation of coordinated dinitrogen in a ditantalum complex: Cleavage and functionalization of N-2}, journal = {Journal of the American Chemical Society}, volume = {128}, number = {29}, year = {2006}, note = {ISI Document Delivery No.: 064WLTimes Cited: 19Cited Reference Count: 44MacKay, Bruce A. Munha, Rui F. Fryzuk, Michael D.}, month = {Jul}, pages = {9472-9483}, type = {Article}, abstract = {{The dinitrogen complex ([NPN]Ta)(2)(mu(1)-eta(2):eta(2)-N-2)(mu-H)(2), 1, (where [NPN] = (PhNSiMe2CH2)(2)PPh) undergoes hydrosilylation with primary and secondary alkyl- and arylsilanes, giving a new N-Si bond and a new terminal tantalum hydride derived from one Si-H unit. Various primary silanes can be employed to give isolable complexes of the general formula ([NPN]TaH)(mu-N-N-SiHnR3-n)(mu-H)(2)(Ta[NPN]) (5}, keywords = {CATALYTIC-REDUCTION, END-ON, LIGAND, METAL-COMPLEXES, MOLECULAR NITROGEN, MOLYBDENUM, N BOND-CLEAVAGE, SIDE-ON, TERMINAL ALKYNES, TRIAMIDOAMINE COMPLEXES}, isbn = {0002-7863}, url = {://000239120700063}, author = {MacKay, B. A. and Munha, R. F. and Fryzuk,Michael D.} } @article {1476, title = {Synthesis and reactivity of side-on-bound dinitrogen metal complexes}, journal = {Organometallics}, volume = {25}, number = {7}, year = {2006}, note = {ISI Document Delivery No.: 025SVTimes Cited: 59Cited Reference Count: 107}, month = {Mar}, pages = {1530-1543}, type = {Review}, abstract = {An up-to-date account of the Synthesis of side-on-bound dinitrogen complexes of the lanthanides, the actinides, and the transition elements over the past 40 years is given. In addition, the reactivity of these derivatives is summarized. There have been many complicated multinuclear Cluster complexes with the N-2 imbedded in a fashion that corresponds to side-on N-2. There have been some suggestions, as early as 1960. that side-on dinitrogen complexes should exist. However, a key date in this area is 1988, which is when the disamarium Complex (CP*Sm-2)(2)(mu-eta(2):eta(2)-N-2) was reported. It is this date that is used in this account as the real starting point for the area of side-on dinitrogen coordination chemistry. After 1988, side-on dinitrogen complexes are reviewed from the point of view of Synthesis, structure (N-N bond lengths, where applicable), and reactivity. What becomes apparent is that while there have been many new side-on dinitrogen complexes discovered recently, investigations into their reactivity patterns are still at a primitive stage.}, keywords = {BRIDGING N-2 UNIT, COORDINATED DINITROGEN, DINUCLEAR TANTALUM COMPLEX, ELECTRONIC-STRUCTURE, END-ON, MOLECULAR NITROGEN, NICKEL-LITHIUM COMPLEX, RAY CRYSTAL-STRUCTURE, REDUCTION SYSTEM, X-RAY}, isbn = {0276-7333}, url = {://000236288100002}, author = {MacLachlan, E. A. and Fryzuk,Michael D.} } @article {1185, title = {Functionalization and cleavage of coordinated dinitrogen via hydroboration using primary and secondary boranes}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {83}, number = {4}, year = {2005}, note = {ISI Document Delivery No.: 921DLTimes Cited: 14Cited Reference Count: 30}, month = {Apr}, pages = {315-323}, type = {Article}, abstract = {The reaction of the side-on, end-on ditantalum dinitrogen complex ([NPN]Ta)(2)(mu-eta(1):eta(2)-N-2)(mu-H)(2) (where NPN = PhP(CH2SiMe2NPh)(2)) with a variety of secondary and primary boranes is reported. With 9-BBN, hydroboration of the Ta2N2 unit occurs via B-H addition, which in turn triggers a cascade of reactions that result in N-N bond cleavage, ancillary ligand rearrangement involving silicon group migration, and finally elimination of benzene from the N-Ph group and a B-H moiety to generate the imide-nitride derivative. In the presence of excess 9-BBN, the Lewis acid - base adduct of the imide-nitride ([NP mu-N]Ta(=NBC8H14)(mu-NB(H)C8H14)Ta[NPN]) is formed. A similar set of reactions is observed for dicyclohexylborane (Cy2BH), which hydroborates the dinitrogen complex to generate [NPN]Ta(H)(mu-eta(1):eta(2)-NNBCy2)(mu-H)(2)Ta[NPN], followed by loss of H-2 and silicon group migration to yield the imide-nitride [NP mu-N]Ta(=NBCy2)(mu-N)(Ta[NPN]. With thexyl borane (H2BCMe2CHMe2), a similar sequence of reactions is suggested starting with hydroboration to generate [NPN]Ta(H)(mu-eta(1):eta(2)-NNB(H)C6H13)(mu-H)(2)Ta[NPN], followed by loss of H-2 and ancillary ligand rearrangement. When bis(pentafluorophenyl)borane (HB(C6F5)(2)) is used, no hydroboration of coordinated N-2 is observed, rather simple adduct formation to give ([NPN]Ta)(2)(mu-eta(1):eta(2)-NN-B(H)(C6F5)(2))(mu-H)(2) occurs.}, keywords = {ACTIVATION, ammonia, CHEMISTRY, DINITROGEN, END-ON, FIXATION, hydroboration, METAL-COMPLEXES, MOLECULAR NITROGEN, MOLYBDENUM, N-2, N-N bond cleavage, SIDE-ON, tantalum}, isbn = {0008-4042}, url = {://000228744300008}, author = {MacKay, B. A. and Johnson, S. A. and Patrick, B. O. and Fryzuk,Michael D.} } @article {1186, title = {Hydroalumination of a dinuclear tantalum dinitrogen complex: N-N bond cleavage and ancillary ligand rearrangement}, journal = {Organometallics}, volume = {24}, number = {16}, year = {2005}, note = {ISI Document Delivery No.: 949ZKTimes Cited: 15Cited Reference Count: 32}, month = {Aug}, pages = {3836-3841}, type = {Article}, abstract = {The addition of diisobutylaluminum hydride (DIBAL) to the side-on end-on dinitrogen complex ([NPN]Ta)(2)(mu-eta(1):eta(2)-N-2)(mu-H)(2), 1 (where [NPN] = (PhNSiMe2CH2)(2)PPh), is described. The two end products are diastereomeric rotational isomers in which N-N bond cleavage has occurred with an Al(Bu-i)H group attached to one of the nitride atoms. The reaction proceeds through addition of DIBAL to 1 to generate a thermally sensitive intermediate that has been characterized in solution as the result of Al-H addition across the TaN2 moiety, namely, ([NPN]TaH)(mu-eta(1):eta(2)-NNA1(i)Bu(2))(mu-H)(2)(Ta[NPN), 2. This material subsequently rearranges via a second thermally labile intermediate to ultimately generate two diastereomeric end products that show N-N bond cleavage, loss of H-2, loss of an aluminum isobutyl group, and NPN ligand migration from tantalum to aluminum. Both of these complexes have been isolated in crystalline form and analyzed by single-crystal X-ray diffraction. The second thermally sensitive intermediate has been characterized on the basis of multinuclear NMR spectroscopy as ([NPN]TaH)(mu-eta(1):eta(2)-(NNAlBu)-Bu-i(mu-H))(mu-H)(2)(Ta[NPN), 3.}, keywords = {ACTIVATION, ATMOSPHERIC NITROGEN, CHEMISTRY, COORDINATED DINITROGEN, END-ON, FUNCTIONALIZATION, METAL-COMPLEXES, MOLECULAR NITROGEN, N-2, SIDE-ON}, isbn = {0276-7333}, url = {://000230827200007}, author = {MacKay, B. A. and Patrick, B. O. and Fryzuk,Michael D.} } @article {1187, title = {A new arene-bridged diamidophosphine ligand and its coordination chemistry with zirconium(IV)}, journal = {Organometallics}, volume = {24}, number = {6}, year = {2005}, note = {ISI Document Delivery No.: 904YFTimes Cited: 15Cited Reference Count: 48}, month = {Mar}, pages = {1112-1118}, type = {Article}, abstract = {The arene-bridged dilithium diamidophosphine ligand, [(2,4,6-Me3C6H2)NLi-2-(5-MeC6H3)](2)PPh, [NPN]*Li-2, was prepared from (2,4,6-Me3C6H2)(2-Br-4-MeC6H3)NH, (BuLi)-Bu-n, and PhPCl2 in Et2O and isolated as a dioxane adduct in similar to 85\% yield. The solid-state structure of [NPN]*Li-2(THF)2 as determined by X-ray diffraction shows both lithiums bridged by the amido nitrogens with one Li ion coordinated to the phosphine donor. The reaction of [NPN]*H-2 and Zr(NMe2)(4) in toluene produced [NPN]*Zr(NMe2)(2) in 90\% isolated yield. Addition of excess Me3SiCl to [NPN]*Zr(NMe2)(2) converts it to [NPN]*ZrCl2 in high yield. The solid-state structure of [NPN] *ZrCl2 as determined by X-ray diffraction shows the Zr center is a distorted trigonal bipyramid with the phosphine and the chloride apical. The ortho-Me{\textquoteright}s on the N-mesityl moiety are inequivalent in both the Li and Zr complexes of [NPN]* by NMR spectroscopy, while in [NPN]*H-2 MesN ortho-Me{\textquoteright}s appear as broad singlets. VT-NMR of [NPN]*H-2 indicated that Delta G(rot)(double dagger) of MesC(ipso)-N is approximately 15.5 +/- 0.3 kcal mol(-1). The thermally labile and light-sensitive zirconium dimethyl complex [NPN]*ZrMe2 was prepared from [NPN]*ZrCl2 and MeMgCl in Et2O in 80\% yield.}, keywords = {CLEAVAGE, COMPLEX, COUPLING REACTIONS, DINITROGEN LIGAND, END-ON, METAL-COMPLEXES, MOLECULAR NITROGEN, N-2 UNIT, palladium, SIDE-ON, tantalum}, isbn = {0276-7333}, url = {://000227533800014}, author = {MacLachlan, E. A. and Fryzuk,Michael D.} } @article {947, title = {Carbon-nitrogen bond formation via the reaction of terminal alkynes with a dinuclear side-on dinitrogen complex}, journal = {Journal of the American Chemical Society}, volume = {126}, number = {31}, year = {2004}, note = {ISI Document Delivery No.: 843TSTimes Cited: 27Cited Reference Count: 21}, month = {Aug}, pages = {9480-9481}, type = {Article}, keywords = {ACTIVATION, COORDINATION, FIXATION, FUNCTIONALIZATION, HETEROCYCLES, HYDROAMINATION, METAL-COMPLEXES, MOLECULAR NITROGEN, MOLYBDENUM, N-2}, isbn = {0002-7863}, url = {://000223110100007}, author = {Morello, L. and Love, J. B. and Patrick, B. O. and Fryzuk,Michael D.} }