Electronic versus steric control in palladium complexes of carboranyl phosphine-iminophosphorane ligands

2019 ◽  
Vol 48 (2) ◽  
pp. 486-503
Author(s):  
José Luis Rodríguez-Rey ◽  
David Esteban-Gómez ◽  
Carlos Platas-Iglesias ◽  
Antonio Sousa-Pedrares

Subtle changes in the electronic properties of C- and B3-carboranyl phosphineiminophosphoranes allows a fine control of the donor ability of the imine nitrogen atom, which results in Pd complexes with the ligands providing (P,N)-chelating or P-terminal coordination.

2009 ◽  
Vol 64 (11-12) ◽  
pp. 1381-1386 ◽  
Author(s):  
Zureima García-Hernández ◽  
François P. Gabbaï

Lithiation of 2-(2-bromophenyl)-dioxolane (1) followed by reaction with dimesitylboron fluoride afforded 2-(2-dimesitylborylphenyl)-dioxolane (2) which was deprotected to afford 2- dimesitylboryl-benzaldehyde (3). Compound 3 reacts with aliphatic amines such as n-butylamine and ethanolamine to afford the corresponding imines 2-(dimesitylboryl)benzylidenebutylamine (4) and 2-(dimesitylboryl)benzylideneethanolamine (5), respectively. Structural studies indicate coordination of the imine-nitrogen atom to the boron center. Imines 4 and 5 emit a green fluorescence near 510 nm with quantum yields approaching 10%. TD-DFT calculations suggest that this emission arises from an intramolecular charge-transfer excited state


Author(s):  
Sarr Mamour ◽  
Diop Mayoro ◽  
Thiam Elhadj Ibrahima ◽  
Gaye Mohamed ◽  
Barry Aliou Hamady ◽  
...  

The 2-hydrazinopyridine precursor has been widely used to prepare ligands of various kinds by condensation with carbonyl compounds. These types of ligands are suitable for synthesizing novel transition metal (II) complexes with interesting magnetic properties. In this context we have synthesized the ligand 1-(2-hydroxyphenyl-2-ethylidene)-2-(pyridin-2-yl)hydrazine (HL) which was used in the preparation of the mononuclear title complex, [Ni(C13H12N3O)(C13H13N3O)]NO3·0.5H2O. As a result of the presence of HL and L in the [{Ni(HL)(L)}]+ unit, the complex appears to be a supramolecular dimer composed of the Δ(−) and Λ(−) optical isomers, which are linked by strong hydrogen-bonds. As well as the dimer generated by two mononuclear [{Ni(HL)(L)}]+ cations, the asymmetric unit also contains two nitrate anions and one water molecule. Each Ni atom is coordinated to two ligand molecules by a nitrogen atom of the pyridine ring, an imine nitrogen atom and a phenolic oxygen atom of one of the ligand molecules and a phenolate oxygen atom of the other organic molecules. The environment around the cation is a distorted octahedron. The basal planes are defined by the two nitrogen atoms of the pyridine rings and the two phenolic oxygen atoms of the ligand, the apical positions being occupied by the azomethine atoms. The O atoms of one of the nitrate ions are disordered over two sets of sites in a 0.745 (9):0.255 (9) ratio. In the crystal, the dimers are linked by numerous hydrogen bonds, forming a three-dimensional framework.


Author(s):  
Uwe Böhme ◽  
Anke Schwarzer ◽  
Betty Günther

The reaction of dichlorodimethylsilane with a polydentate Schiff base ligand derived from pyridoxal and 2-ethanolamine yielded the macrocyclic silicon compound (8E,22E)-4,4,12,18,18,26-hexamethyl-3,5,17,19-tetraoxa-8,13,22,27-tetraaza-4,18-disilatricyclo[22.4.0.010,15]octacosa-1(24),8,10,12,14,22,25,27-octaene-11,25-diol, C24H36N4O6Si2. The asymmetric unit contains the half macrocycle with an intramolecular O—H...N hydrogen bond between the imine nitrogen atom and a neighbouring oxygen atom. The crystal structure is dominated by C—H...O and C—H...π interactions, which form a high ordered molecular network.


2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
Neil F. Curtis ◽  
Jan Wikaira

Copper(II) chloride and perchlorate, N,N-diethylethane-1,2-diamine, react in (m)ethanol with acetone and ammonia to form [(2,4-dimethyl-8-ethyl-5,8-diazadec-4-ene-2-amine)chlorocopper(II)] perchlorate, C12H27Cl2CuN3O4, , monoclinic, C2/c, (Hall-C2/c); a, 26.418(1), b, 9.7385(4); c, 14.0993(5) Å; β, 91.134(3)°. This has copper(II) in tetrahedrally distorted square-planar coordination by one primary, one tertiary, and one imine nitrogen atom and the chloride ion.


2001 ◽  
Vol 56 (3) ◽  
pp. 229-232 ◽  
Author(s):  
Elena Labisbal ◽  
Alfonso Castiñeiras ◽  
Christine A. Brown ◽  
Douglas X. West

Abstract Zinc, 2,6-Diacetylpyridine Bis{N(4)-dimethylthiosemicarbazone}, Electrochemical Synthesis Zinc metal was oxidized in the presence of 2,6-diacetylpyridine bis{N(4)-dimethylthiosemi-carbazone} (2 ,6H2Ac4DM) in an acetonitrile solution, to produce a complex of the formula [Zn(2 ,6Ac4DM)]2-CH3CN. One of the zinc atoms is distorted octahedrally 6-coordinate and the coordination involves both pyridyl nitrogen atoms of the two ligands, the imine nitrogen atom and the thiolato sulfur atom of one thiosemicarbazone moiety of each ligand. The other zinc center is distorted tetrahedrally 4-coordinate with NS coordination of the two remaining thiosemicarbazone moieties. The complex crystallizes in the monoclinic space group C2/c with a = 14.952(2), b = 17.656(3), c = 15.553(4) Å, ß = 111.456(16)°, V= 3821.5(13) Å3 and Z = 4.


2010 ◽  
Vol 82 (3) ◽  
pp. 541-554 ◽  
Author(s):  
Toshiaki Murai

This review illustrates the ready availability of thioamide dianions and their versatility as carbon nucleophiles adjacent to the nitrogen atom. The products derived from the addition of thioamide dianions to a range of electrophiles can participate in a cyclization reaction to form nitrogen-containing heterocycles. The electronic properties of thioamide dianions are also considered.


2020 ◽  
Vol 56 (61) ◽  
pp. 8524-8536 ◽  
Author(s):  
Wentao Xu ◽  
Muzi Li ◽  
Liancheng Qiao ◽  
Jin Xie

In this highlight, we provide a current perspective of synthetic methodology development catalyzed by dinuclear Ni- and Pd-complexes in the past decade. The new catalytic reactivities of dinuclear Ni- and Pd-complexes are discussed.


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