RESUMEN
A bis(diphenyl)-phosphine functionalized ß-diketimine ligand (PNac-H) was applied for the synthesis of a subvalent Ni(I) complex [PNac-Ni]. Here, the Ni(I) center is stabilized by a tetradentate PNNP-type pocket, forming a square planar coordination sphere. Subsequently, the Ni(I) complex was investigated with regard to its reactivity and the activation of small molecules. The reductive potential of Ni(I) enabled an activation of different substrate classes, such as CH2 X2 (X=Br, I), I2 or Ph2 E2 (E=S, Se). The ligand's design allows a stabilization of the reactive Ni(I) species while at the same time enabling activation processes due to a hemilabile coordination behavior and accessible axial coordination sites. The activation products have been characterized by single crystal X-ray diffraction, NMR and IR spectroscopy as well as elemental analysis.
RESUMEN
The versatile metalloligand [{HCîCC(NDipp)2}2Au2] (dipp = 2,6-diisopropylphenyl) was converted into early-late heterotetrametallic complexes [{ClCp2MCîCC(NDipp)2}2Au2] (M = Ti, Zr). These compounds show photoluminescence with either remarkably different (Ti) or similar (Zr) features as compared to related solely coinage metal containing acetylide amidinate complexes.
RESUMEN
Reaction of the PNNP ligand system N,N'-bis[(2-diphenylphosphino)phenyl]formamidinate (dpfam) featuring different coordination compartments with [AuCl(tht)], [CuMes]5, [AgMes]4, or [AuC6F5(tht)] (tht = tetrahydrothiophene) resulted in tetranuclear homo- and heterometallic coinage metal complexes, as well as a hexanuclear gold complex. All of them feature a metal string conformation. Photophysical investigation revealed a significant dependence of the photoluminescence properties on the metal composition. Below 100 K, the PL efficiency of three compounds approaches nearly 100%.
RESUMEN
This review covers the compound class of one-dimensional gold strings. These compounds feature a formally infinite repetition of gold complexes as monomers/repeating units that are held together by aurophilic interactions, i.e. direct gold-gold contacts. Their molecular structures are primarily determined in the solid state using single crystal X-ray diffraction. The chemical composition of the employed gold complexes is diverse and furthermore plays a key role in terms of structure characteristics and the resulting properties. One of the most common features of gold strings is their photoluminescence upon UV excitation. The emission energy is often dependent on the distance of adjacent gold ions and the electronic structure of the whole string. In terms of gold strings, these parameters can be fine-tuned by external stimuli such as solvent, pH value, pressure or mechanical stress. This leads to direct structure-property correlations, not only with regard to the photophysical properties, but also electric conductivity for potential application in nanoelectronics. Concerning these correlations, gold strings, consisting of self-assembled individual complexes as building blocks, are the ideal compound class to look at, as perturbations by an inhomogeneity in the ligand sphere (such as the end of a molecule) can be neglected. Therefore, the aim of this review is to shed light on the past achievements and current developments in this area.
RESUMEN
The synthesis of linear symmetric ethynyl- and acetylide-amidinates of the coinage metals is presented. Starting with the desilylation of the complexes [{Me3 SiC≡CC(NDipp)2 }2 M2 ] (Dipp=2,6-diisopropylphenyl) (M=Cu, Au) it is demonstrated that this compound class is suitable to serve as a versatile metalloligand. Deprotonation with n-butyllithium and subsequent salt metathesis reactions yield symmetric tetranuclear gold(I) acetylide complexes of the form [{(PPh3 )AuC≡CC(NDipp)2 }2 M2 ] (M=Cu, Au). The corresponding Ag complex [{(PPh3 )AuC≡CC(NDipp)2 }2 Ag2 ] was obtained by a different route via metal rearrangement. All compounds show bright blue or blue-green microsecond long phosphorescence in the solid state, hence their photophysical properties were thoroughly investigated in a temperature range of 20-295â K. Emission quantum yields of up to 41 % at room temperature were determined. Furthermore, similar emissions with quantum yields of 15 % were observed for the two most brightly luminescent complexes in thf solution.
RESUMEN
Diphenylphosphine functionalized propionic acid was applied for the synthesis of heteromultimetallic dimolybdenum(ii) complexes. The ligand features both carboxylic acid and phosphine functionalities, allowing the selective synthesis of a tetracarboxylate bridged Mo2(ii)-paddlewheel structure in a first step. Due to the symmetrically arranged phosphine functionalities, the dimolybdenum(ii) complex was utilized as a metalloligand. Subsequent coordination of late transition metal ions, such as gold(i), rhodium(i), iridium(i) or ruthenium(ii) to the phosphine moieties allowed the formation of heteromultimetallic structures. The flexibility of the diphenylphosphino propionate ligand system enabled intermolecular aurophilic interactions in the Au(i) functionalized dimolybdenum(ii) complexes. Depending on the Au(i) species applied, either a dimeric structure or a 1D coordination polymer was formed in the solid state. These structures represent the first examples of heterometallic dimolybdenum(ii) complexes, forming supramolecular structures via aurophilic interactions.
RESUMEN
A series of homo- and hetero-polynuclear coinage metal complexes based on a phosphine-substituted 1,2,3-triazole system is presented. Besides the P,N-ligand 1-benzyl-4-(diphenylphosphanyl)-1H-1,2,3-triazole (LPN), the P,C-donor ligand 1-benzyl-4-(diphenylphosphanyl)-3-methyl-1H-1,2,3-triazolium (LPCH+), featuring a potential mesoionic carbene moiety, was obtained by methylation of LPN. Starting from the monogold chloride complexes AuCl(LPN/LPC), the syntheses of a heterotrinuclear Au2Cu complex as well as a digold carbene complex are described. The multinuclear complexes show metallophilic interactions. Their photophysical properties were investigated by temperature-dependent photoluminescence (PL) measurements. In particular, the digold complex shows interesting PL properties including narrow exciton peaks arising in the excitation and emission spectra below 50 K. These might be related to the molecular 'chains' in the crystal structure of the digold complex, formed by phenyl ligand stacking.
RESUMEN
Ethynylferrocene (FcC≡CH) was utilized as a redox-active metalloligand for the synthesis of polynuclear coinage metal complexes. The reaction of [FcC≡CLi] with tri- tert-butylphosphine metal chlorides [tBu3P-MCl] (M = Au, Ag, Cu) yielded different heteronuclear ferrocene-funtionalized alkyne complexes featuring metallophilic interactions. Furthermore, the redox properties of the ferrocenyl-functionalized tetracopper complex were investigated by cyclic voltammetry and UV-vis-near-IR spectroelectrochemistry. They indicate the compounds' redox-rich nature and a weak electronic coupling between the redox-active ferrocenyl units over a large distance.
RESUMEN
Bis(acetylido) aurates(I) and thallium(I) trifluoromethylsulfonates were used to synthesize AuI -TlI metallopolymers, displaying novel and unusual structural motifs of the metal-metal backbones in the solid state: a discrete molecular cluster, 1D chains of interconnected dimers, tetramers, or dodecamers of Au-Tl units, and a 2D-plane network, consisting of alternating edge-linked (AuTl)6 and (AuTl)4 cycles. The formation of the different architectures was primarily controlled by the steric demand of the acetylide-substituent groups. Thus, the bulkiest 2,6-diisopropylphenyl derivative yielded a molecular cluster [Tl2 Au3 ]. Most compounds showed bright visible photoluminescence with quantum yields of up to 25 % at ambient temperature. The color of the emitted light significantly differs with the network structure. Furthermore, theoretical studies of singlet excitations in the molecular cluster, as well as NMR and mass-spectrometric investigations of the fragmentation of the metallopolymers in solution are described in detail.
RESUMEN
The ligand [{Me3SiC[triple bond, length as m-dash]CC(NDipp)2}Li(thf)3] (Dipp = 2,6-diisopropylphenyl) was used for salt metathesis reactions with [AuCl(tht)] (tht = tetrahydrothiophene) to obtain the dinuclear alkyne functionalized bisamidinate [{Me3SiC[triple bond, length as m-dash]CC(NDipp)2}2Au2]. This compound serves as a building block for the polynuclear carbide bridged gold(i) amidinate complex [Au8{µ3-(η1:η2-C[triple bond, length as m-dash]C)}2(Me3SiC[triple bond, length as m-dash]CC(NDipp)2)4(tht)2], which is the first gold(i) complex with a µ3-η1:η2 carbide coordination. Both gold(i) compounds show distinct aurophilic interactions and are remarkably stable at ambient conditions. Photophysical investigations revealed intense luminescence with notable high quantum yields both in the solid state and in solution.