Pyridyl Containing 1,5-Diaza-3,7-diphosphacyclooctanes as Bridging Ligands for Dinuclear Copper(I) Complexes

Abstract

1,5-bis(R)-3,7-bis[2-(pyridine-2Ј-yl)ethyl)-1,5-diaza-3,7-diphosphacyclooctanes 1 and 2 and their copper(I) complexes 3 and 4 were developed. The butterfly-shaped copper-iodide core and unusual P,N-chelate and P,P-bridged coordination mode of the heterocyclic ligand in the dinuclear complexes 3 and 4 were revealed. Complexes 3 895 and 4 display emission in green range of spectra, with lifetimes in a microsecond domain and quantum yields of luminescence in solidstate up to 38 %. Thermochromic effects found for the phosphorescence of 4 in solutions are ascribed to rigidochromism.

Assembly of Heterometallic AuICu2I2 Cores on the Scaffold of NPPN-Bridging Cyclic Bisphosphine

“…Our previous works demonstrated that N-aryl-substituted 1,5-diaza-3,7-diphosphacyclooctanes 1 and 2 are structurally preorganized for a bridging coordination of copper­(I) and gold­(I) cations. ,− The 1:1 reaction of ligands 1 and 2 with [AuCl­(tht)] (tht = tetrahydrothiophene) or AuI in acetone led to the formation of macrocyclic P,P-bridged bimetallic gold­(I) complexes 3 – 6 , respectively (Scheme ).…”

“…Most of the P,N-ligands used for the synthesis of heterometallic Au I /Ag I or Au I /Cu I complexes are the pyridine-2-ylphosphine and analogous phosphines with an N-heterocycle, where an N-heterocyclic group is directly connected toward a P-donor center. ,, Spatial distancing of the pyridyl group from the phosphorus coordination center opens the way to the principally different coordination properties. , Surprisingly, ligands, such as PyCH 2 PR 2 or Py­(CH 2 ) 2 PR 2 with spatial outlying of P- and N-donor centers, are not well studied concerning the synthesis of copper­(I) and gold­(I) complexes . Heterocyclic bisphosphines with exocyclic pyridylethyl groups are promising P,P- or P,N-bridging platforms for the construction of polynuclear complexes displaying intensive luminescence and/or stimuli-responsive luminescence. ,, In 2019, we presented the synthesis and structure of the hexanuclear copper­(I) complexes containing two Cu 3 I 3 units based on tetradentate N Py ,P,P,N Py -bridging 1,5-diaza-3,7-diphosphacyclooctanes bearing two exocyclic pyridylethyl substituents at the phosphorus atoms. The structure of the obtained complexes was unusual due to the assembly of novel trinuclear copper­(I) moieties stabilized by four donor centers of two ligands.…”

“…39 Heterocyclic bisphosphines with exocyclic pyridylethyl groups are promising P,P-or P,N-bridging platforms for the construction of polynuclear complexes displaying intensive luminescence and/or stimuli-responsive luminescence. 37,38,40 In 2019, we presented the synthesis and structure of the hexanuclear copper(I) complexes containing two Cu 3 I 3 units based on tetradentate N Py ,P,P,N Py -bridging 1,5-diaza-3,7-diphosphacyclooctanes bearing two exocyclic pyridylethyl substituents at the phosphorus atoms. The structure of the obtained complexes was unusual due to the assembly of novel trinuclear copper(I) moieties stabilized by four donor centers of two ligands.…”

Investigation on the photophysical properties of Cu(I) complexes supported by N‐heterocyclic carbene ligands with electron‐donating/withdrawing groups on imidazolylidene unit

“…Unlike the low‐energy CT absorption bands, the emission spectra of these complexes do not exhibit red‐shift compared to that of [Cu(Pyim)(POP)](PF 6 ), which may be caused by the interactions between the complexes and PMMA. Four‐coordinate Cu(I) complexes undergo a coordination geometry relaxation at excited state, which leads to the flattening of tetrahedral coordination geometry and decreases the energy level of excited state [13,39–40] . The relaxation can be more impeded in crystal than in PMMA film, thus the emission spectra acquired in PMMA film show obviously red‐shift compared to those acquired in crystal.…”

“…Four-coordinate Cu(I) complexes undergo a coordination geometry relaxation at excited state, which leads to the flattening of tetrahedral coordination geometry and decreases the energy level of excited state. [13,[39][40] The relaxation can be more impeded in crystal than in PMMA film, thus the emission spectra acquired in PMMA film show obviously redshift compared to those acquired in crystal.…”