Synthesis, Characterization and Monoalkene Polymerization Activity of Bis-[(1,2,3,4-tetraphenyl)-η5-cyclopentadienyl]zirconium(IV) Dichloride

1995 ◽  
Vol 50 (3) ◽  
pp. 411-414 ◽  
Author(s):  
Giuseppe Conti ◽  
Guillermo Arribas ◽  
Angelina Altomare ◽  
Bernardo Mendez ◽  
Francesco Ciardelli
Keyword(s):  
Catalytic System ◽  
Active Site ◽  
Title Complex ◽  
Electronic Effects ◽  
Ethylene Oligomers

The title complex (1) has been prepared by reaction of ZrCl4 with 1,2,3,4-(tetraphenyl)- cyclopenta-1,3-dienyl lithium (2). The phenyl substituents on the metallocene ligands exert both steric and electronic effects on the active site obtained by activation of 1 with MAO. Thus this catalytic system shows lower polymerization activity than in case of unsubstituted or methyl-substituted ligands and leads to the formation of ethylene oligomers.

ChemInform Abstract: Stereoselective Addition of Aliphatic Thiols to Internal Alkynes in a Catalytic System with Palladium “Nanosalt” as an Active Site.

ChemInform ◽  
2014 ◽  
Vol 45 (14) ◽  
pp. no-no
Author(s):  
N. V. Orlov ◽  
I. V. Chistyakov ◽  
Z. A. Starikova ◽  
V. P. Ananikov ◽  
I. P. Beletskaya
Keyword(s):  
Catalytic System ◽  
Active Site ◽  
Stereoselective Addition ◽  
Internal Alkynes ◽  
Aliphatic Thiols

Vibrational Spectra of the Layered Compound [(VO2)2(4,4-bipy)0.5(4,4′- Hbipy)(PO4)]·H2O

2003 ◽  
Vol 58 (5) ◽  
pp. 485-488 ◽  
Author(s):  
Enrique J Baran ◽  
Kwang-Hwa Lii
Keyword(s):  
Raman Spectra ◽  
Vibrational Spectra ◽  
Active Site ◽  
Spectroscopic Properties ◽  
Title Complex ◽  
Layered Compound ◽  
Infrared And Raman Spectra

The infrared and Raman spectra of the title complex were recorded and assignments for the VO+2 , PO3-4 and V-O and V-N skeletal vibrations are proposed. The results are of interest in relation to the vibrational-spectroscopic properties of the active site of vanadium haloperoxidases.

Stereoselective addition of aliphatic thiols to internal alkynes in a catalytic system with palladium “nanosalt” as an active site

2013 ◽  
Vol 62 (1) ◽  
pp. 47-54 ◽  
Author(s):  
N. V. Orlov ◽  
I. V. Chistyakov ◽  
Z. A. Starikova ◽  
V. P. Ananikov ◽  
I. P. Beletskaya
Keyword(s):  
Catalytic System ◽  
Active Site ◽  
Stereoselective Addition ◽  
Internal Alkynes ◽  
Aliphatic Thiols

Chiral carbon dots - a functional domain for tyrosinase Cu active site modulation via remote target interaction

Nanoscale ◽  
2021 ◽  
Author(s):  
Yurong Ma ◽  
Mengling Zhang ◽  
Zhixiong Deng ◽  
Xiting Wang ◽  
Hui Huang ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Catalytic System ◽  
Active Site ◽  
Carbon Dots ◽  
Functional Domain ◽  
Target Interaction ◽  
Hybrid Enzyme ◽  
Chiral Carbon

Nano-hybrid-enzyme is an ideal catalytic system that integrates various advantages from biocatalysis, nanocatalysis to homogeneous and heterogeneous catalysis. However, great efforts are still needed to fully understand the interactions between...

scholarly journals Crystal structure of NiFe(CO)5[tris(pyridylmethyl)azaphosphatrane]: a synthetic mimic of the NiFe hydrogenase active site incorporating a pendant pyridine base

2019 ◽  
Vol 75 (4) ◽  
pp. 438-442 ◽  
Author(s):  
Natwara Sutthirat ◽  
Joseph W. Ziller ◽  
Jenny Y. Yang ◽  
Zachary Thammavongsy
Keyword(s):  
Crystal Structure ◽  
Ir Spectroscopy ◽  
Hydrogen Bonds ◽  
Active Site ◽  
Title Complex ◽  
Reduced Form ◽  
Supramolecular Framework ◽  
Complex Molecules ◽  
Π Interactions

The reaction of Ni(TPAP)(COD) {where TPAP = [(NC5H4)CH2]3P(NC2H4)3N} with Fe(CO)5 resulted in the isolation of the title heterobimetallic NiFe(TPAP)(CO)5 complex di-μ-carbonyl-tricarbonyl[2,8,9-tris(pyridin-2-ylmethyl)-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane]ironnickel, [FeNi(C24H30N7P)(CO)5]. Characterization of the complex by 1H and 31P NMR as well as IR spectroscopy are presented. The structure of NiFe(TPAP)(CO)5 reveals three terminally bound CO molecules on Fe0, two bridging CO molecules between Ni0 and Fe0, and TPAP coordinated to Ni0. The Ni—Fe bond length is 2.4828 (4) Å, similar to that of the reduced form of the active site of NiFe hydrogenase (∼2.5 Å). Additionally, a proximal pendant base from one of the non-coordinating pyridine groups of TPAP is also present. Although involvement of a pendant base has been cited in the mechanism of NiFe hydrogenase, this moiety has yet to be incorporated in a structurally characterized synthetic mimic with key structural motifs (terminally bound CO or CN ligands on Fe). Thus, the title complex NiFe(TPAP)(CO)5 is an unique synthetic model for NiFe hydrogenase. In the crystal, the complex molecules are linked by C—H...O hydrogen bonds, forming undulating layers parallel to (100). Within the layers, there are offset π–π [intercentroid distance = 3.2739 (5) Å] and C—H...π interactions present. The layers are linked by further C—H...π interactions, forming a supramolecular framework.

Angiotensin as a model for hormone – receptor interactions

1985 ◽  
Vol 5 (5) ◽  
pp. 407-416 ◽  
Author(s):  
Graham J. Moore ◽  
John M. Matsoukas
Keyword(s):  
Magnetic Resonance ◽  
Protease Inhibitors ◽  
Active Site ◽  
Serine Proteases ◽  
Proton Magnetic Resonance ◽  
Chemical Reactivity ◽  
Receptor Activation ◽  
Electronic Effects ◽  
Relay System ◽  
Receptor Interactions

Proton magnetic resonance and chemical reactivity studies have demonstrated the presence of a tyrosine charge relay system in angiotensin which is analogous to the serine charge relay system present at the active site of serine proteases. Receptor activation by angiotensin can be explained by electronic effects deriving from an interaction of the charge relay system with stacking of the histidine and phenylalanine rings. Experiments with serine protease inhibitors suggest the possibility that mechanistic features of the interaction of angiotensin with its receptors may apply to other ‘phenoxyl’ hormones including certain peptides, steroids and catecholamines.

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