00603nas a2200169   4500008004100000245007700041210006900118260000800187300001500195490000700210100002200217700002500239700002300264700002400287700002400311856009800335       2016                        eng d00aImpact of modular substitution on crystal packing: the tale of two ureas0 aImpact of modular substitution on crystal packing the tale of tw  cAUG  a 7078-70940 v181 aKoshti, Vijay, S.1 aThorat, Shridhar, H.1 aGote, Ravindra, P.1 aChikkali, Samir, H.1 aGonnade, Rajesh, G.  uhttps://library.ncl.res.in/content/impact-modular-substitution-crystal-packing-tale-two-ureas01794nas a2200157   4500008004100000022001500041245009300056210006900149260000800218300001400226520120700240100002201447700002301469700002401492856012001516       2018                        eng d  a 1434-193X00aAccelerated and enantioselective synthesis of a library of p-stereogenic urea phosphines0 aAccelerated and enantioselective synthesis of a library of pster  cDEC  a6768-67793 aChiral phosphorus ligands play a central role in majority of the asymmetric transformations. However, access to chiral phosphorus ligands is limited due to their challenging synthesis. Reported here is a highly efficient and accelerated catalytic asymmetric synthesis of P-stereogenic urea containing phosphines leading to a small library of 18 chiral phosphorus compounds. Characteristic two doublets in a P-31 NMR spectrum, spectroscopic and analytical evidences authenticated the formation of [Pd-{(S,S) Me-FerroLANE}(m-phenylurea)(I)] complex. Indeed, [Pd-{(S,S) Me-FerroLANE}(m-phenylurea)(I)] was found to catalyze the C-P coupling reaction and quantitative conversion was observed within 18 hours. Under optimized conditions, iodophenyl urea's (2a-2j) were treated with secondary phosphines (1a-1c) in presence of [Pd-{(S,S) Me-FerroLANE}(m-phenylurea)(I)] to obtain P-stereogenic urea phosphines 5a-5r. The identity of these urea derived phosphines was unambiguously ascertained using a combination of spectroscopic and analytical methods. The catalyst tolerated various functional groups and yielded corresponding urea containing phosphines with an enantiomeric excess in the range of 15-62 %.1 aKoshti, Vijay, S.1 aGote, Ravindra, P.1 aChikkali, Samir, H.  uhttps://library.ncl.res.in/content/accelerated-and-enantioselective-synthesis-library-p-stereogenic-urea-phosphines02653nas a2200217   4500008004100000022001400041245012000055210006900175260000900244300001400253490000700267520188500274100002302159700001702182700001702199700002702216700001802243700002102261700002402282856012902306       2018                        eng d  a0024-929700aJudicious reduction of supported Ti catalyst enables access to disentangled ultrahigh molecular weight polyethylene0 aJudicious reduction of supported Ti catalyst enables access to d  cJUN   a4541-45520 v513 a<p>Heterogeneous Ziegler-Natta and homogeneous metallocene catalysts are known to produce ultrahigh molecular weight polyethylene (UHMWPE) in the entangled state. On the other hand, only (two) homogeneous single-site catalysts are reported to yield disentangled UHMWPE (dis-UHMWPE). This disparity between the two types of catalysts and the two states of polyethylene can be bridged if a heterogeneous single-site catalyst that can yield dis-UHMWPE is made accessible. Here, one-pot two-step synthesis of a MgCl2 supported [Ti(OEt)(4)] derived catalyst 1 with a two-stage activation strategy is reported to produce dis-UHMWPE. Second activation of catalyst 1 was performed by adding excess modified methylaluminoxane (MMAO12), and XPS analysis indicated that the catalyst existed in only Ti(III) state at [A1]/[Ti] ratio of 600. Catalyst 1 after second activation with MMAO12 was found to be highly active in ethylene polymerization and produced dis-UHMWPE. Polymerization conditions were tailored to obtain molecular weight (M-w) as high as 13 million g/mol PE. To the best of our knowledge, this is the first time a heterogeneous catalyst (catalyst 1) that displays pseudosingle site nature is able to produce dis-UHMWPE. The thus-prepared nascent polyethylene revealed a melting temperature of 141-144 degrees C, which is a characteristic melting transition for a dis-UHMVVPE. The disentangled state of the nascent PE and its M-w and MVVD were further authenticated by rheological investigations. Isothermal time, sweep oscillatory experiments in linear viscoelastic limit revealed a rapid rise in elastic modulus followed by equilibration to plateau modulus, which are characteristic features of the disentangled state. Thus, a pseudo-singlesite heterogeneous catalyst has been accessed, which upon second activation with excess MMAO12 led to the production of dis-UHMWPE.</p>1 aGote, Ravindra, P.1 aMandal, Dipa1 aPatel, Ketan1 aChaudhuri, Krishnaroop1 aVinod, C., P.1 aLele, Ashish, K.1 aChikkali, Samir, H.  uhttps://library.ncl.res.in/content/judicious-reduction-supported-ti-catalyst-enables-access-disentangled-ultrahigh-molecular