scholarly journals X-ray crystallography and electrochemistry reveal electronic and steric effects of phosphine and phosphite ligands in complexes RuII(κ4-bda)(PR3)2 and RuII(κ3-bda)(PR3)3 (bda = 2,2′-bipyridine-6,6′-dicarboxylato)

Polyhedron ◽  
2019 ◽  
Vol 161 ◽  
pp. 63-70 ◽  
Author(s):  
Sima Yazdani ◽  
Braden E. Silva ◽  
Thomas C. Cao ◽  
Arnold L. Rheingold ◽  
Douglas B. Grotjahn
Keyword(s):  
Steric Effects ◽  
X Ray ◽  
X Ray Crystallography ◽  
Phosphite Ligands ◽  
Electronic And Steric Effects

Study of naphthopyran derivatives: structure and photochromic properties in solution and in polymer film

2021 ◽  
Vol 77 (7) ◽  
Author(s):  
Linqi Shi ◽  
Zipei Sun ◽  
Jiajie Tian ◽  
Yaodong Huang ◽  
Jiben Meng
Keyword(s):  
Uv Light ◽  
Steric Effects ◽  
Pmma Film ◽  
Structure Property ◽  
Photochromic Properties ◽  
X Ray ◽  
Structure Property Relationships ◽  
Substituent Group ◽  
Uv Light Irradiation ◽  
Electronic And Steric Effects

Four naphthopyran derivatives, namely, 3,3-bis(naphthalen-1-yl)-3H-naphtho[2,1-b]pyran, C33H22O, NP1, 3,3-bis([1,1′-biphenyl]-4-yl)-3H-naphtho[2,1-b]pyran, C37H26O, NP2, 3,3-bis(4-phenoxyphenyl)-3H-naphtho[2,1-b]pyran, C37H26O2, NP3, and 3,3-bis(4-methoxy-2-methylphenyl)-3H-naphtho[2,1-b]pyran, C29H26O3, NP4, were synthesized and their photochromic properties investigated. NP1–NP4 exhibited good photochromism in different solutions and in poly(methyl methacrylate) (PMMA) film under UV light irradiation. Solvatochromism and the electronic and steric effects of the substituent group on photochromism were analyzed and decolouration curves were found to fit a monoexponential kinetic decay in most cases. Single-crystal X-ray analysis of NP1 and NP2 revealed the structure–property relationships. Good fatigue resistance of NP1, both in solution and in the PMMA film, endows it with potential value for applications.

Reaction of [Fe(CO)4(η2-Me3SiC≡CSiMe3)] with PMe3 — CO rather than alkyne substitution

2005 ◽  
Vol 83 (6-7) ◽  
pp. 862-868 ◽  
Author(s):  
James NL Dennett ◽  
Michael J Ferguson ◽  
Robert McDonald ◽  
Josef Takats
Keyword(s):  
Iron Carbonyl ◽  
Steric Effects ◽  
X Ray ◽  
Co Substitution ◽  
X Ray Crystallography

Reaction of [Fe(CO)4(η2-BTMSA)] (1) (BTMSA = Me3SiCCSiMe3) with trimethylphosphine proceeds by stepwise loss of CO ligands yielding [Fe(CO)3(PMe3)(η2-BTMSA)] (2) and [Fe(CO)2(PMe3)2(η2-BTMSA)] (3), respectively. This demonstrates the CO dissociative nature of substitution in 1 toward PMe3, as established in analogous M(CO)4(η2-alkyne) (M = Fe, Ru, Os) compounds. The structures of all three compounds have been determined by X-ray crystallography to assess the effect of CO substitution by PMe3 on the metal–alkyne bonding in these molecules.Key words: iron, carbonyl, alkyne, substitution, phosphine, steric effects.

scholarly journals Steric Effects of Alkyl Substituents at N-Donor Bidentate Amines Direct the Nuclearity, Bonding and Bridging Modes in Thiocyanato-Copper(II) Complexes

2018 ◽  
Author(s):  
Franz A. Mautner ◽  
Roland C. Fischer ◽  
Ana Torvisco ◽  
Maher M. Henary ◽  
Andrew Milner ◽  
...  
Keyword(s):  
Density Functional ◽  
Steric Effects ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Crystallography ◽  
Monomeric Complex ◽  
Vis Spectroscopy ◽  
Specific Geometry ◽  
Bonding And Bridging

A series of Cu(II)-thiocyanato complexes derived from sterically hindered N-donors diamines were synthesized and characterized: catena-[Cu(Me3en)(μ-NCS)(NCS)] (1), catena-[Cu(NEt2Meen)(μ-NCS)(NCS)] (2), catena-[Cu(N,N,2,2-Me4pn)(μ-NCS)(NCS)] (3), the dimeric: [Cu2(N,N′-isp2en)2(μ-NCS)2(NCS)2] (4) and the monomeric complex [Cu(N,N′-t-Bu2en)(NCS)2] (5), where Me3en = N,N,N′-Trimethylethylenediamine, NEt2Meen = N,N-diethyl-N′-methylethylenediamine, N,N,2,2-Me4pn = N,N,2,2-tetramethylpropylenediamine, N,N′-isp2en = N,N′-diisopropylethylenediamine and N,N′-t-Bu2en = N,N′-di(tert-butyl)ethylenediamine. The complexes were characterized by elemental microanalyse, IR and UV-Vis spectroscopy and single crystal X-ray crystallography. Density Functional Theory was used to evaluate the role of steric effects in compounds 4 and 5 and how this may affect the adaption of a specific geometry, NCS-bonding mode and the dimensionality of the resulting complex.

scholarly journals Steric Effects of Alkyl Substituents at N-Donor Bidentate Amines Direct the Nuclearity, Bonding and Bridging Modes in Isothiocyanato-Copper(II) Coordination Compounds

Crystals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 38 ◽  
Author(s):  
Franz Mautner ◽  
Roland Fischer ◽  
Ana Torvisco ◽  
Maher Henary ◽  
Andrew Milner ◽  
...  
Keyword(s):  
Coordination Compounds ◽  
Density Functional ◽  
Steric Effects ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Crystallography ◽  
Vis Spectroscopy ◽  
Specific Geometry ◽  
Bonding And Bridging

A series of Cu(II)-isothiocyanato coordination compounds derived from sterically hindered N-donor diamines were synthesized and characterized: catena-[Cu(Me3en)(μ-NCS)(NCS)] (1), catena-[Cu(NEt2Meen)(μ-NCS)(NCS)] (2), catena-[Cu(N,N,2,2-Me4pn)(μ-NCS)(NCS)] (3), the dimeric: [Cu2(N,N′-isp2en)2(µ-NCS)2(NCS)2] (4) and the monomeric compound [Cu(N,N′-t-Bu2en)(NCS)2] (5), where Me3en = N,N,N′-trimethylethylenediamine, NEt2Meen = N,N-diethyl-N′-methylethylenediamine, N,N,2,2-Me4pn = N,N,2,2-tetramethylpropylenediamine, N,N′-isp2en = N,N′-diisopropylethylenediamine and N,N′-t-Bu2en = N,N′-di(tert-butyl)ethylenediamine. The coordination compounds were characterized by elemental microanalyses, IR, and UV–Vis spectroscopy as well as single crystal X-ray crystallography. Density Functional Theory (DFT) was used to evaluate the role of steric effects in compounds 4 and 5 and how this may affect the adaption of a specific geometry, NCS-bonding mode, and the dimensionality of the resulting coordination compound.

Phosphine–phosphite ligands in the palladium-catalyzed asymmetric allylic alkylation: Electronic and steric effects

2013 ◽  
Vol 36 ◽  
pp. 94-97 ◽  
Author(s):  
Gergely Farkas ◽  
Zsófia Császár ◽  
Szabolcs Balogh ◽  
Áron Szöllősy ◽  
Maryse Gouygou ◽  
...  
Keyword(s):  
Steric Effects ◽  
Allylic Alkylation ◽  
Asymmetric Allylic Alkylation ◽  
Palladium Catalyzed ◽  
Phosphite Ligands ◽  
Electronic And Steric Effects

scholarly journals Aza-Diels–Alder reaction between N-aryl-1-oxo-1H-isoindolium ions and tert-enamides: Steric effects on reaction outcome

2014 ◽  
Vol 10 ◽  
pp. 848-857 ◽  
Author(s):  
Amitabh Jha ◽  
Ting-Yi Chou ◽  
Zainab ALJaroudi ◽  
Bobby D Ellis ◽  
T Stanley Cameron
Keyword(s):  
Molecular Modelling ◽  
Alder Reaction ◽  
Diels Alder ◽  
Probable Mechanism ◽  
Steric Effects ◽  
X Ray ◽  
X Ray Crystallography ◽  
Diels Alder Reaction ◽  
Steric Hinderance ◽  
Mechanism Of The Reaction

The synthesis of 5-substituted 6,6a-dihydroisoindolo[2,1-a]quinolin-11(5H)-ones via [4 + 2] imino-Diels–Alder cyclization from N-aryl-3-hydroxyisoindolinones and N-vinyl lactams under Lewis acid-catalysed anhydrous conditions is reported. Reactions of N-(2-substituted-aryl)-3-hydroxyisoindolinones with N-vinylpyrrolidone under identical conditions resulted in the formation of 2-(2-substitued-aryl)-3-(2-(2-oxopyrrolidin-1-yl)vinyl)isoindolin-1-one analogues indicating steric hinderance as the cause of deviation. The probable mechanism of the reaction based on the results from X-ray crystallography and molecular modelling is discussed.

Difference Fourier Analysis of Glucose Embedded and Frozen Hydrated Purple Membrane

1982 ◽  
Vol 40 ◽  
pp. 74-75
Author(s):  
Jules S. Jaffe ◽  
Robert M. Glaeser
Keyword(s):  
Purple Membrane ◽  
Data Set ◽  
High Resolution Data ◽  
X Ray ◽  
X Ray Crystallography ◽  
Fourier Techniques ◽  
Versus Protein ◽  
The Difference ◽  
Difference Fourier ◽  
Ideal Method

Although difference Fourier techniques are standard in X-ray crystallography it has only been very recently that electron crystallographers have been able to take advantage of this method. We have combined a high resolution data set for frozen glucose embedded Purple Membrane (PM) with a data set collected from PM prepared in the frozen hydrated state in order to visualize any differences in structure due to the different methods of preparation. The increased contrast between protein-ice versus protein-glucose may prove to be an advantage of the frozen hydrated technique for visualizing those parts of bacteriorhodopsin that are embedded in glucose. In addition, surface groups of the protein may be disordered in glucose and ordered in the frozen state. The sensitivity of the difference Fourier technique to small changes in structure provides an ideal method for testing this hypothesis.

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