Results 81 to 90 of about 902,813 (269)

Atomic‐scale structure elucidation of refractory metal carbides derived from metallocene‐based preceramics

Journal of the American Ceramic Society, Volume 108, Issue 12, December 2025.
Abstract Polymer‐derived ceramics (PDCs) are becoming an alluring class of materials that can incorporate the ceramic chemistries found in ultra‐high‐temperature ceramics, such as Ti, Zr, and Hf carbides. The use of polymeric materials intrinsically enables processing techniques with a higher degree of complexity in a more straightforward fashion, such
Stephanie L. Chua, Haira G. Hackbarth, James F. Ponder Jr., Nicholas D. Posey, Yuwei Yang, Pierre‐Olivier Autran, Matthew B. Dickerson, Timothy L. Pruyn, Nicholas M. Bedford   +8 more
wiley   +1 more source

Catalisadores metalocênicos: aspectos gerais e heterogeneização Metallocene catalysts: general aspects and heterogenization

Polímeros, 1998
Este trabalho apresenta uma discussão sobre aspectos gerais da nova tecnologia de síntese de polímeros com microestrutura e propriedades controladas, obtidos via sistema catalítico metaloceno/MAO.
Maria de Fátima V. Marques, Patricia Aragão C. Junior, Maria José C. Guimarães, Fernanda M. B. Coutinho   +3 more
doaj   +1 more source

Cat-CrNP as new material with catalytic properties for 2-chloro-2-propen-1-ol and ethylene oligomerizations

Scientific Reports, 2021
The contemporary search for new catalysts for olefin oligomerization and polymerization is based on the study of coordinating compounds and/or organometallic compounds as post-metallocene catalysts.
Jacek Malinowski, Dagmara Jacewicz, Artur Sikorski, Mariusz Urbaniak, Przemysław Rybiński, Patrycja Parnicka, Adriana Zaleska-Medynska, Barbara Gawdzik, Joanna Drzeżdżon   +8 more
doaj   +1 more source

2,3‐Diboratabutadiene Complexes of Group 4 Metals and their Donor‐Induced Oxidative Cleavage to Methyleneboranes

ChemistryEurope, Volume 3, Issue 6, November 11, 2025.
GA: We here report the first perarylated 2,3‐diboratabutadiene dianion and its reaction with Cp2MCl2 (M = Zr, Hf) to afford unprecedented 2,3‐diboratabutadiene π‐complexes with unique coordination modes. Addition of an N‐heterocyclic carbene (NHC) to the complexes gives rise to the donor‐induced oxidation of the BB bond, resulting in two separate NHC ...
Philipp Grewelinger, Carsten Präsang, Bernd Morgenstern, David Scheschkewitz   +3 more
wiley   +1 more source

Six-coordinated half-metallocene catalyst for ethylene polymerization and its mechanism study

Giant
The demand for catalysts capable of enabling olefin polymerization at elevated temperatures to meet industrial requirements continues to grow. Among emerging candidates, novel six-coordinated half-metallocene catalysts, which combine the advantages of ...
Qian Li, Zifang Guo, Shuzhang Qu, Xinwei Li, Jian Chen, Yiming Wei, Cui Zheng, Zhihui Song, Yue Lan, Zhao Wen, Chaofan Yu   +10 more
doaj   +1 more source

In situ synthesis of nanoclay filled polyethylene using polymer supported metallocene catalyst system

Química Nova, 2011
In situ ethylene polymerizations were performed using bis(cyclopentadiene)titanium dichloride supported on polyethersulfone as catalyst. The bis(cyclopentadiene)titanium dichloride supported on polyethersulfone catalyst activity estimated by ethylene ...
Z. V. P Murthy, Parimal A Parikh, Smitha Rajesh   +2 more
doaj   +1 more source

Cp* Noninnocence Leads to a Remarkably Weak C–H Bond via Metallocene Protonation [PDF]

, 2019
Metallocenes, including their permethylated variants, are extremely important in organometallic chemistry. In particular, many are synthetically useful either as oxidants (e.g., Cp_2Fe^+) or as reductants (e.g., Cp_2Co, Cp*_2Co, and Cp*_2Cr).
Chalkley, Matthew J., Oyala, Paul H., Peters, Jonas C.   +2 more
core   +5 more sources

Predicting Ti‐49 NMR Chemical Shift With New NMR‐DKH Basis Set

Journal of Computational Chemistry, Volume 46, Issue 29, 05 November 2025.
A new NMR‐DKH basis set was proposed for Ti atom and the δ49Ti was studied in a set of 41 + 9 (calibration‐blue/validation‐red) Ti(IV) complexes, resulting in a mean absolute deviation of only 50 ppm with the GIAO‐OLYP/NMR‐DKH/IEF‐PCM(UFF)//BLYP/def2‐SVP/IEF‐PCM(UFF) protocol.
Matheus Gunar Ramalho Gomes, Catherine Rodrigues Siqueira de Souza, Diego Fernando da Silva Paschoal, Wagner Batista De Almeida   +3 more
wiley   +1 more source

Fe-Mediated Nitrogen Fixation with a Metallocene Mediator: Exploring pK_a Effects and Demonstrating Electrocatalysis [PDF]

, 2018
Substrate selectivity in reductive multi-electron/proton catalysis with small molecules such as N_2, CO_2, and O_2 is a major challenge for catalyst design, especially where the competing hydrogen evolution reaction (HER) is thermodynamically and ...
Chalkley, Matthew J., Del Castillo, Trevor J., Matson, Benjamin D., Peters, Jonas C.   +3 more
core   +1 more source

Dibora[2]ferrocenophane: a carbene-stabilized diborene in a strained cis-configuration [PDF]

, 2016
Unsaturated bridges that link the two cyclopentadienyl ligands together in strained ansa metallocenes are rare and limited to carbon-carbon double bonds. The synthesis and isolation of a strained ferrocenophane containing an unsaturated two-boron bridge,
Braunschweig, Holger, Krummenacher, Ivo, Lichtenberg, Crispin, Mattock, James D, Schmidt, Uwe, Schneider, Christoph, Schäfer, Marius, Steffenhagen, Thomas, Ullrich, Stefan, Vargas, Alfredo   +9 more
core   +1 more source