6 research outputs found
Luminescence Solvato- and Vapochromism of Alkynyl-Phosphine Copper Clusters
The reaction of [Cu(NCMe)4][PF6] with aromatic acetylenes HC2R and triphosphine 1,1,1-tris(diphenylphosphino)methane in the presence of NEt3 results in the formation of hexanuclear Cu(I) clusters with the general formula [Cu6(C2R)4{(PPh2)3CH}2][PF6]2 (R = 4-X-C6H4 (1-5) and C5H4N (6); X = NMe2 (1), OMe (2), H (3), Ph (4), CF3 (5)). The structural motif of the complexes studied consists of a Cu6 metal core supported by two phosphine ligands and stabilized by σ- and π-coordination of the alkynyl fragments (together with coordination of pyridine nitrogen atoms in cluster 6). The solid state structures of complexes 2-6 were determined by single crystal XRD analysis. The structures of the complexes in solution were elucidated by (1)H, (31)P, (1)H-(1)H COSY NMR spectroscopy, and ESI mass spectrometry. Clusters 1-6 exhibit moderately strong phosphorescence in the solid state with quantum yields up to 17%. Complexes 1-5 were found to form solvates (acetone, acetonitrile) in the solid state. The coordination of loosely bound solvent molecules strongly affects emission characteristics and leads to solvato- and vapochromic behavior of the clusters. Thus, solvent-free and acetonitrile solvated forms of 3 demonstrate contrasting emission in orange (615 nm) and blue (475 nm) regions, respectively. The computational studies show that alkynyl-centered IL transitions mixed with those of MLCT between the Cu6 metal core and the ligand environment play a dominant role in the formation of excited states and can be considerably modulated by weakly coordinating solvent molecules leading to luminescence vapochromism.This research has been supported by St. Petersburg State University Research Grant 0.37.169.2014, and Russian Foundation for Basic Research Grants 13-03-00970, 14-03-32077, and 13-03-12411. Academy of Finland (Grant 268993/2013, I.O.K), University of Eastern Finland (strategic funding—Russian–Finnish collaborative project), is also gratefully acknowledged. The work was carried out using equipment of the Analytical Center of Nano- and Biotechnologies of SPbSPU with financial support of the Ministry of Education and Science of Russian Federation; Centers for Magnetic Resonance, X-ray Diffraction Studies, Chemical Analysis and Materials Research, Optical and Laser Materials Research; and Computer Center of St. Petersburg State University
Luminescence solvato-and vapochromism of alkynyl-phosphine copper clusters
The reaction of [Cu(NCMe)4][PF6] with aromatic acetylenes HC2R and triphosphine 1,1,1-tris(diphenylphosphino)methane in the presence of NEt3 results in the formation of hexanuclear Cu(I) clusters with the general formula [Cu6(C2R)4{(PPh2)3CH}2][PF6]2 (R = 4-X-C6H4 (1–5) and C5H4N (6); X = NMe2 (1), OMe (2), H (3), Ph (4), CF3 (5)). The structural motif of the complexes studied consists of a Cu6 metal core supported by two phosphine ligands and stabilized by σ- and π-coordination of the alkynyl fragments (together with coordination of pyridine nitrogen atoms in cluster 6). The solid state structures of complexes 2–6 were determined by single crystal XRD analysis. The structures of the complexes in solution were elucidated by 1H, 31P, 1H–1H COSY NMR spectroscopy, and ESI mass spectrometry. Clusters 1–6 exhibit moderately strong phosphorescence in the solid state with quantum yields up to 17%. Complexes 1–5 were found to form solvates (acetone, acetonitrile) in the solid state. The coordination of loosely bound solvent molecules strongly affects emission characteristics and leads to solvato- and vapochromic behavior of the clusters. Thus, solvent-free and acetonitrile solvated forms of 3 demonstrate contrasting emission in orange (615 nm) and blue (475 nm) regions, respectively. The computational studies show that alkynyl-centered IL transitions mixed with those of MLCT between the Cu6 metal core and the ligand environment play a dominant role in the formation of excited states and can be considerably modulated by weakly coordinating solvent molecules leading to luminescence vapochromism
Silver Alkynyl-Phosphine Clusters: An Electronic Effect of the Alkynes Defines Structural Diversity
The face-capping triphosphine, 1,1,1-tris(diphenylphosphino)methane
(tppm), together with bridging alkynyl ligands and the counterions,
facilitates the formation of a family of silver complexes, which adopt
cluster frameworks of variable nuclearity. The hexanuclear compounds
[Ag<sub>6</sub>(C<sub>2</sub>C<sub>6</sub>H<sub>4</sub>-4-X)<sub>3</sub>(tppm)<sub>2</sub>(An<sup>–</sup>)<sub>3</sub>] (X = H (<b>1</b>), CF<sub>3</sub> (<b>2</b>), OMe (<b>3</b>), An<sup>–</sup> = CF<sub>3</sub>SO<sub>3</sub><sup>–</sup>; X = OMe (<b>4</b>), An<sup>–</sup> = CF<sub>3</sub>COO<sup>–</sup>) are produced for the electron-accepting
to moderately electron-donating alkynes and the appropriate stoichiometry
of the reagents. <b>1</b> and <b>3</b> undergo an expansion
of the metal core when treated with 1 equiv of Ag<sup>+</sup> to give
the species [Ag<sub>7</sub>(C<sub>2</sub>C<sub>6</sub>H<sub>4</sub>-4-X)<sub>3</sub>(tppm)<sub>2</sub>(CF<sub>3</sub>SO<sub>3</sub>)<sub>3</sub>](CF<sub>3</sub>SO<sub>3</sub>) (X = H (<b>5</b>), OMe (<b>6</b>)). The electron-donating
substituent (X = NMe<sub>2</sub>) particularly favors this Ag<sub>7</sub> arrangement (<b>7</b>) that undergoes geometry changes
upon alkynylation, resulting in the capped prismatic cluster [Ag<sub>7</sub>(C<sub>2</sub>C<sub>6</sub>H<sub>4</sub>-4-NMe<sub>2</sub>)<sub>4</sub>(tppm)<sub>2</sub>(CF<sub>3</sub>SO<sub>3</sub>)](CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub> (<b>8</b>). Alternatively, for the aliphatic <i><sup>t</sup></i>Bu-alkyne, only the octanuclear complex [Ag<sub>8</sub>(C<sub>2</sub>Bu<sup><i>t</i></sup>)<sub>4</sub>{(PPh<sub>2</sub>)<sub>3</sub>CH}<sub>2</sub>(CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub>](CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub> (<b>9</b>) is observed. The structures
of <b>1</b>–<b>4</b> and <b>6</b>–<b>9</b> were determined by X-ray diffraction analysis. In solution,
all the studied compounds were found to be stereochemically nonrigid
that prevented their investigation in the fluid medium. In the solid
state, clusters <b>2</b>, <b>3</b>, <b>5</b>–<b>8</b> exhibit room temperature
luminescence of triplet origin (maximum Φ<sub>em</sub> = 27%,
λ<sub>em</sub> = 485–725 nm). The observed emission is
assigned mainly to [<i>d</i>(Ag) → π*(alkyne)]
electronic transitions on the basis of TD-DFT computational analysis
Silver Alkynyl-Phosphine Clusters: An Electronic Effect of the Alkynes Defines Structural Diversity
The face-capping triphosphine, 1,1,1-tris(diphenylphosphino)methane
(tppm), together with bridging alkynyl ligands and the counterions,
facilitates the formation of a family of silver complexes, which adopt
cluster frameworks of variable nuclearity. The hexanuclear compounds
[Ag<sub>6</sub>(C<sub>2</sub>C<sub>6</sub>H<sub>4</sub>-4-X)<sub>3</sub>(tppm)<sub>2</sub>(An<sup>–</sup>)<sub>3</sub>] (X = H (<b>1</b>), CF<sub>3</sub> (<b>2</b>), OMe (<b>3</b>), An<sup>–</sup> = CF<sub>3</sub>SO<sub>3</sub><sup>–</sup>; X = OMe (<b>4</b>), An<sup>–</sup> = CF<sub>3</sub>COO<sup>–</sup>) are produced for the electron-accepting
to moderately electron-donating alkynes and the appropriate stoichiometry
of the reagents. <b>1</b> and <b>3</b> undergo an expansion
of the metal core when treated with 1 equiv of Ag<sup>+</sup> to give
the species [Ag<sub>7</sub>(C<sub>2</sub>C<sub>6</sub>H<sub>4</sub>-4-X)<sub>3</sub>(tppm)<sub>2</sub>(CF<sub>3</sub>SO<sub>3</sub>)<sub>3</sub>](CF<sub>3</sub>SO<sub>3</sub>) (X = H (<b>5</b>), OMe (<b>6</b>)). The electron-donating
substituent (X = NMe<sub>2</sub>) particularly favors this Ag<sub>7</sub> arrangement (<b>7</b>) that undergoes geometry changes
upon alkynylation, resulting in the capped prismatic cluster [Ag<sub>7</sub>(C<sub>2</sub>C<sub>6</sub>H<sub>4</sub>-4-NMe<sub>2</sub>)<sub>4</sub>(tppm)<sub>2</sub>(CF<sub>3</sub>SO<sub>3</sub>)](CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub> (<b>8</b>). Alternatively, for the aliphatic <i><sup>t</sup></i>Bu-alkyne, only the octanuclear complex [Ag<sub>8</sub>(C<sub>2</sub>Bu<sup><i>t</i></sup>)<sub>4</sub>{(PPh<sub>2</sub>)<sub>3</sub>CH}<sub>2</sub>(CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub>](CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub> (<b>9</b>) is observed. The structures
of <b>1</b>–<b>4</b> and <b>6</b>–<b>9</b> were determined by X-ray diffraction analysis. In solution,
all the studied compounds were found to be stereochemically nonrigid
that prevented their investigation in the fluid medium. In the solid
state, clusters <b>2</b>, <b>3</b>, <b>5</b>–<b>8</b> exhibit room temperature
luminescence of triplet origin (maximum Φ<sub>em</sub> = 27%,
λ<sub>em</sub> = 485–725 nm). The observed emission is
assigned mainly to [<i>d</i>(Ag) → π*(alkyne)]
electronic transitions on the basis of TD-DFT computational analysis
Silver Alkynyl-Phosphine Clusters: An Electronic Effect of the Alkynes Defines Structural Diversity
The face-capping triphosphine, 1,1,1-tris(diphenylphosphino)methane
(tppm), together with bridging alkynyl ligands and the counterions,
facilitates the formation of a family of silver complexes, which adopt
cluster frameworks of variable nuclearity. The hexanuclear compounds
[Ag<sub>6</sub>(C<sub>2</sub>C<sub>6</sub>H<sub>4</sub>-4-X)<sub>3</sub>(tppm)<sub>2</sub>(An<sup>–</sup>)<sub>3</sub>] (X = H (<b>1</b>), CF<sub>3</sub> (<b>2</b>), OMe (<b>3</b>), An<sup>–</sup> = CF<sub>3</sub>SO<sub>3</sub><sup>–</sup>; X = OMe (<b>4</b>), An<sup>–</sup> = CF<sub>3</sub>COO<sup>–</sup>) are produced for the electron-accepting
to moderately electron-donating alkynes and the appropriate stoichiometry
of the reagents. <b>1</b> and <b>3</b> undergo an expansion
of the metal core when treated with 1 equiv of Ag<sup>+</sup> to give
the species [Ag<sub>7</sub>(C<sub>2</sub>C<sub>6</sub>H<sub>4</sub>-4-X)<sub>3</sub>(tppm)<sub>2</sub>(CF<sub>3</sub>SO<sub>3</sub>)<sub>3</sub>](CF<sub>3</sub>SO<sub>3</sub>) (X = H (<b>5</b>), OMe (<b>6</b>)). The electron-donating
substituent (X = NMe<sub>2</sub>) particularly favors this Ag<sub>7</sub> arrangement (<b>7</b>) that undergoes geometry changes
upon alkynylation, resulting in the capped prismatic cluster [Ag<sub>7</sub>(C<sub>2</sub>C<sub>6</sub>H<sub>4</sub>-4-NMe<sub>2</sub>)<sub>4</sub>(tppm)<sub>2</sub>(CF<sub>3</sub>SO<sub>3</sub>)](CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub> (<b>8</b>). Alternatively, for the aliphatic <i><sup>t</sup></i>Bu-alkyne, only the octanuclear complex [Ag<sub>8</sub>(C<sub>2</sub>Bu<sup><i>t</i></sup>)<sub>4</sub>{(PPh<sub>2</sub>)<sub>3</sub>CH}<sub>2</sub>(CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub>](CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub> (<b>9</b>) is observed. The structures
of <b>1</b>–<b>4</b> and <b>6</b>–<b>9</b> were determined by X-ray diffraction analysis. In solution,
all the studied compounds were found to be stereochemically nonrigid
that prevented their investigation in the fluid medium. In the solid
state, clusters <b>2</b>, <b>3</b>, <b>5</b>–<b>8</b> exhibit room temperature
luminescence of triplet origin (maximum Φ<sub>em</sub> = 27%,
λ<sub>em</sub> = 485–725 nm). The observed emission is
assigned mainly to [<i>d</i>(Ag) → π*(alkyne)]
electronic transitions on the basis of TD-DFT computational analysis