Octahedral metal carbonyls. 63. Chelate ring displacement of DTHp from cis-(DTHp)W(CO)4 by Lewis bases (DTHp = 2,2,6,6-tetramethyl-3,5-dithiaheptane, Lewis base = L (phosphine, phosphite))

1988 ◽  
Vol 27 (19) ◽  
pp. 3308-3314 ◽  
Author(s):  
Gerard R. Dobson ◽  
Jose E. Cortes
Keyword(s):  
Chelate Ring ◽  
Lewis Base ◽  
Metal Carbonyls ◽  
Lewis Bases

scholarly journals Relativistic Effects on NMR Parameters of Halogen-Bonded Complexes

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4399 ◽  
Author(s):  
Ibon Alkorta ◽  
José Elguero ◽  
Manuel Yáñez ◽  
Otilia Mó ◽  
M. Merced Montero-Campillo
Keyword(s):  
Relativistic Effects ◽  
Lewis Base ◽  
Coupling Constants ◽  
Basic Site ◽  
Lewis Bases ◽  
Nmr Parameters ◽  
Quadrupolar Coupling ◽  
Binary Complexes ◽  
Computational Level ◽  
Bonded Complexes

Relativistic effects are found to be important for the estimation of NMR parameters in halogen-bonded complexes, mainly when they involve the heavier elements, iodine and astatine. A detailed study of 60 binary complexes formed between dihalogen molecules (XY with X, Y = F, Cl, Br, I and At) and four Lewis bases (NH3, H2O, PH3 and SH2) was carried out at the MP2/aug-cc-pVTZ/aug-cc-pVTZ-PP computational level to show the extent of these effects. The NMR parameters (shielding and nuclear quadrupolar coupling constants) were computed using the relativistic Hamiltonian ZORA and compared to the values obtained with a non-relativistic Hamiltonian. The results show a mixture of the importance of the relativistic corrections as both the size of the halogen atom and the proximity of this atom to the basic site of the Lewis base increase.

scholarly journals 5-Nitrosalicylic Acid and its Proton-Transfer Compounds with Aliphatic Lewis Bases

2005 ◽  
Vol 58 (1) ◽  
pp. 47 ◽  
Author(s):  
Graham Smith ◽  
Andy W. Hartono ◽  
Urs D. Wermuth ◽  
Peter C. Healy ◽  
Jonathan M. White ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Lewis Base ◽  
Unusual Structure ◽  
Lewis Bases ◽  
Carboxylate Oxygen ◽  
Hydrogen Bonding Interactions ◽  
Polymer Compound ◽  
Proton Transfer Compounds ◽  
Centrosymmetric Dimers

The crystal structures of the proton-transfer compounds of 5-nitrosalicylic acid (5-nsa) with morpholine (morph), hexamethylenetetramine (hmt), and ethylenediamine (en) have been determined and their solid-state packing structures described. The compounds are [(morph)+(5-nsa)–] 1, [(hmt)+(5-nsa)–·H2O] 2, and [(en)2+2(5-nsa)–·H2O] 3. In all compounds, protonation of the hetero-nitrogen of the Lewis base occurs. With 1, the 5-nsa anions and the morpholine cations lie, respectively, in or across crystallographic mirror planes and are linked within the planes by hydrogen-bonding interactions through the aminium group and the carboxylic and phenolic oxygens of the anionic 5-nsa species giving a two-dimensional sheet polymer. Compound 2 is an unusual structure with the planar 5-nsa anions lying within pseudo mirror planes and cyclically linked by duplex water bridges through a single carboxylate oxygen into centrosymmetric dimers. The hmt cation molecules are disordered across the pseudo mirror and are strongly linked by N+–H···O hydrogen bonds only to the water molecules with peripheral weak hmt C–H···O hydrogen bonds extending the dimer within and between the dimer planes. Compound 3 is a network polymer comprised of the 5-nsa anions, the en dianions, and the water molecule in an extensive hydrogen-bonded structure.

scholarly journals Recent Synthesis Developments of Organoboron Compounds via Metal-Free Catalytic Borylation of Alkynes and Alkenes

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 101 ◽  
Author(s):  
Yanmei Wen ◽  
Chunmei Deng ◽  
Jianying Xie ◽  
Xinhuang Kang
Keyword(s):  
Lewis Acids ◽  
Heterocyclic Carbenes ◽  
Lewis Base ◽  
Organoboron Compounds ◽  
Lewis Bases ◽  
Metal Free ◽  
Recent Synthesis

Diboron reagents have been traditionally regarded as “Lewis acids”, which can react with simple Lewis base to create a significant nucleophilic character in one of boryl moieties. In particular, bis(pinacolato)diboron (B2pin2) reacts with simple Lewis bases, such as N-heterocyclic carbenes (NHCs), phosphines and alkoxides. This review focuses on the application of trivalent nucleophilic boryl synthon in the selective preparation of organoboron compounds, mainly through metal-free catalytic diboration and the β-boration reactions of alkynes and alkenes.

Dioxouranium(VI) complexes with N-salicylsalicylaldimines and their Lewis base adducts

1975 ◽  
Vol 28 (4) ◽  
pp. 885 ◽  
Author(s):  
ATT Hsieh ◽  
RM Sheahan ◽  
BO West
Keyword(s):  
Schiff Bases ◽  
Metal Atom ◽  
Lewis Base ◽  
Donor Ligands ◽  
Chelate Complexes ◽  
Nitrogen Donor Ligands ◽  
Uranium Metal ◽  
Lewis Bases ◽  
Nitrogen Donor ◽  
Weak Coordination

New dioxouranium(VI) complexes with the dibasic terdentate Schiff bases, XC6H3(2-OH)CH=N-CH2C6H4(2?-OH) (X = H, 5-Cl or 3-MeO), have been synthesized and characterized as their 1 : 1 alcohol adducts. The labile alcohol molecules in these complexes are readily replaced by various oxygen or nitrogen donor ligands, affording six- or seven- coordinate complexes. Evidence is presented for the rather weak coordination of these Lewis bases to the uranium metal atom. The various possible conformations for these [6,6]-membered chelate complexes are also discussed.

Octahedral metal carbonyls. XVI. Kinetic investigation of the second step of the reaction of o-phenanthrolinetetracarbonylmolybdenum with Lewis bases

1970 ◽  
Vol 9 (5) ◽  
pp. 1286-1289 ◽  
Author(s):  
Douglas Shrader ◽  
Earl P. Ross ◽  
Robert T. Jernigan ◽  
Gerard R. Dobson
Keyword(s):  
Second Step ◽  
Kinetic Investigation ◽  
Metal Carbonyls ◽  
Lewis Bases
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