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1.
Inorg Chem ; 59(1): 244-253, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31814406

RESUMO

A flexible bidentate cyclic phosphine, namely, 1,5-bis(p-tolyl)-3,7-bis(pyridin-2-yl)-1,5-diaza-3,7-diphosphacyclooctane (PNNP), was used as a template to construct a family of binuclear heteroleptic phosphine alkynyl complexes [PNNP(AuC2R)2], with R = Ph, C6H10OH, C5H8OH, (CH3)2COH, Ph2COH. All complexes obtained were characterized by CHN elemental analysis, NMR spectroscopy, and single-crystal X-ray analysis. It was found that the gold(I) complexes demonstrate a different organization of the crystal structure depending on the nature of the cocrystallized solvent (dichloromethane, acetone, and acetonitrile) because of formation of the supramolecular complexes through hydrogen bonding. These weak interactions appear to determine the conformation, packing, and spatial cooperation of flexible complex molecules that are reflected in the photophysical properties, which were carefully investigated in solution and in the solid state. The complexes demonstrate weak emission in solution at room temperature, and freezing results in blue shifting of the emission, which is accompanied by a significant increase in the luminescence intensity. Being isolated from dichloromethane, all gold(I) complexes exhibit green phosphorescence in the solid state, and the complexes with R = Ph and Ph2COH display substantial variation of their emission color after recrystallization from acetone and acetonitrile, respectively, which manifests itself as a significant bathochromic shift of up to 120 nm. The structural nonrigidity of the gold(I) complexes obtained and its impact on the properties of low-energy excited states were investigated in detail by density functional theory calculations, which indicate the significant role of the structural flexibility of the PNNP ligand in the formation of the low-energy excited states and confirm the impact of rotation of the functional groups in the coordination sphere on the emission properties of complexes.

2.
Inorg Chem ; 58(2): 1048-1057, 2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30601648

RESUMO

The unique L2Cu6I6 complexes containing two Cu3I3 units have been obtained via reaction of 1,5-diaza-3,7-diphosphacyclooctanes bearing ethylpyridyl substituents at phosphorus atoms with an excess of copper iodide. The structure of one of the complexes was confirmed by X-ray diffraction. It was shown that the complexes can exist in two crystalline phases with different parameters of the unit cell, which were detected by the PXRD data analyses. The solvent-free crystalline phases of the complexes display rare solid-state white emission at room temperature, which is observed due to the presence of two broad bands in the emission spectra with maxima at 464 and 610 nm. Quantum chemical computations show that the high-energy band has 3(M+X)LCT origin, whereas the low-energy band is interpreted as 3CC. The quantum yields of white luminescence of complexes reach 15-20%.

3.
Dalton Trans ; 44(30): 13565-72, 2015 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-26135988

RESUMO

A novel type of 14-membered cyclic polyphosphine, namely 1,8-diaza-3,6,10,13-tetraphosphacyclotetradecanes 2a­4ahas been synthesized by the condensation of 1,2-bis(phenylphosphino)ethane, formaldehyde and alkylamines (isopropylamine, ethylamine and cyclohexylamine) as a RRRR/SSSS-stereoisomer. The structure of macrocycle 2a was investigated by NMR-spectroscopy and X-ray crystal structure analysis. The unique reversible processes of macrocycles 2a­4a splitting onto the corresponding rac- (2b­4b) and meso- (2c­4c) stereoisomers of 1-aza-3,6-diphosphacycloheptanes were discovered.


Assuntos
Aminas/química , Cicloeptanos/química , Compostos Macrocíclicos/química , Fosfinas/química , Aminas/síntese química , Cristalografia por Raios X , Ciclização , Compostos Macrocíclicos/síntese química , Metilação , Modelos Moleculares , Fosfinas/síntese química , Estereoisomerismo
4.
Chemistry ; 20(11): 3169-82, 2014 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-24523072

RESUMO

Eight-membered cyclic functional bisphosphines, namely 1,5-di-aryl-3,7-di(2-pyridyl)-1,5-diaza-3,7-diphosphacyclooctanes (aryl=2-pyridyl, m-tolyl, p-tolyl, diphenylmethyl, benzyl, (R)-(+)-(α-methyl)benzyl), with 2-pyridyl substituents on the phosphorus atoms have been synthesized by condensation of 2-pyridylphosphine, formaldehyde, and the corresponding primary amine. The structures of some of these bisphosphines have been investigated by X-ray crystallography. The bisphosphines readily form neutral P,P-chelate complexes [(κ(2)-P,P-L)MCl2], cationic bis-P,P-chelate complexes [(κ(2)-P,P-L)2 M](2+), or a five-coordinate complex [(κ(2)-P,P-L)2 NiBr]Br. The electrochemical behavior of two of the nickel complexes, and their catalytic activities in electrochemical hydrogen evolution and hydrogen oxidation, including the fuel-cell test, have been studied.

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