Trinuclear Gold–Carborane Cluster as a Host Structure

This work encompasses a comprehensive study of host–guest interactions between cyclic trimer metal–carborane [Au3(1, 2-C2B10H10)3]3– and several guest species such as cations (H+, Li+, Be2+, Hg2+), anions (F–, H–, Cl–, Br–, I–, HCC–), and neutral molecules (H2, CO2, I2, HCCH, N2). A computational study has been carried out to evaluate energetic profiles and determine the contribution of attractive or repulsive interactions between guest and host. The energy minima obtained call our attention to several cases. For instance, all above cations form stable minima as guest complexes with the three gold atoms of the host. Unexpectedly, pyramidal H– or F– species are obtained as energy minima, while other anions give completely repulsive interactions. Finally, the CO2 molecule is also trapped inside the trinuclear ring

Hydride donating abilities of the tetracoordinated boron hydrides

The hydride donating ability (HDA), determined as Gibbs free energy (ΔG°H −) for the reaction of H− dissociation, was assessed via the DFT/M06/6-311++G (d,p) calculations for 90 tetracoordinated borohydrides Li [L3B-H] taking into account the solvent effects via the optimization in MeCN and CH2Cl2 under SMD model. Obtained this way, the HDAMeCN values vary from 118.2 to 13.4 kcal/mol and correlate well with the Lewis acidity parameters (AN, HA and FA) of parent trigonal boranes (L3B). These data show numerically how the variation of the substituents at the boron atom allows the fine-tuning the B–H bond reactivity (reduction power) in the reactions involving hydride transfer as well as the selectivity of the reduction processes. The analysis of the data obtained shows that by varying the number of substituents and their nature, it is possible not only to change the properties of neutral trisubstituted boranes from highly electrophilic (represented by halogenide- and pseudohalogenide-boranes) to highly nucleophilic (exemplified by alkoxy-an amidoboranes), but also to repolarize the boron-bound hydrogen and make the proton transfer process more favourable than the hydride transfer. © 2018 Elsevier B.V

Macrocyclic copper(I) and silver(I) pyrazolates: Principles of supramolecular assemblies with Lewis bases

Macrocyclic copper(I) and silver(I) pyrazolates represent an important class of coordination compounds used in numerous fundamental areas, such as acid-base chemistry, metallophilic bonding, supramolecular assemblies. In this review we discuss the host-guest complexes of the macrocyclic copper(I) and silver(I) pyrazolates with a wide range of organic and organometallic bases possessing hydride, halide, carbonyl and π-electronic ligands. The purpose of our review is to show the relationship between the solution and solid state chemistry of the target complexes using our approach. The study in solution takes into account a competition between different basic sites of the guest and selectivity of trinuclear macrocycles complexation with certain basic centers. It also allows determining the complexes compositions and their thermodynamic parameters (formation constants, ΔH°, ΔS°). Peculiar features of crystal packing depending on the base type, the complex strength, and the presence of a secondary basic center are summarized and analyzed in this review. This analysis shows how the information on the complexes structure and stability in solution can be used to predict and control the supramolecular architecture in the solid state. © 2017 Elsevier B.V

Synthesis, structures and luminescence of multinuclear silver(i) pyrazolate adducts with 1,10-phenanthroline derivatives

A set of silver(i) 3,5-bis(trifluoromethyl) pyrazolate adducts with 1,10-phenanthroline (L2), 2,9-dimethyl-1,10-phenanthroline (neocuproine, L3) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, L4) was synthesized starting from trimeric silver pyrazolate Ag3Pz3. Reactions with sterically hindered L3 and L4 cause the destruction of the original trimeric core, yielding a dinuclear Ag2Pz2 cycle with an unprecedented chair configuration for L3, while bathocuproine L4 leads to the drastic rearrangement of the silver pyrazolate core into cationic Ag(L4)2 and anionic Ag5Pz6 subunits. All complexes obtained exhibit phosphorescence in the solid state. Time-dependent density functional theory calculations demonstrate their different possible emission processes, explaining their emission behavior as well as their lifetimes. © 2019 The Royal Society of Chemistry

Copper(I) complex with BINAP and 3,5-dimethylpyrazole: synthesis and photoluminescent properties

A reaction of [Cu(MeCN)4]BF4 with PzH (3,5-dimethylpyrazole) and BINAP [2,20-bis(diphenylphosphino)-1,10-binaphthyl] leads to the formation of mononuclear CuI complex [Cu(PzH)(BINAP)]BF4 containing the molecule of nondeprotonated pyrazole and one BINAP ligand with two phosphorus atoms chelating the metal. This complex exhibits a bright phosphorescence originating from the 3(M+L)LCT state at room temperature. At 77 K, the emission is splitted into two components: 3(M+L)LCT and 3LC transitions. © 201

Macrocyclic copper(I) and silver(I) pyrazolates: Principles of supramolecular assemblies with Lewis bases

Macrocyclic copper(I) and silver(I) pyrazolates represent an important class of coordination compounds used in numerous fundamental areas, such as acid-base chemistry, metallophilic bonding, supramolecular assemblies. In this review we discuss the host-guest complexes of the macrocyclic copper(I) and silver(I) pyrazolates with a wide range of organic and organometallic bases possessing hydride, halide, carbonyl and π-electronic ligands. The purpose of our review is to show the relationship between the solution and solid state chemistry of the target complexes using our approach. The study in solution takes into account a competition between different basic sites of the guest and selectivity of trinuclear macrocycles complexation with certain basic centers. It also allows determining the complexes compositions and their thermodynamic parameters (formation constants, ΔH°, ΔS°). Peculiar features of crystal packing depending on the base type, the complex strength, and the presence of a secondary basic center are summarized and analyzed in this review. This analysis shows how the information on the complexes structure and stability in solution can be used to predict and control the supramolecular architecture in the solid state. © 2017 Elsevier B.V

Hydride donating abilities of the tetracoordinated boron hydrides

The hydride donating ability (HDA), determined as Gibbs free energy (ΔG°H −) for the reaction of H− dissociation, was assessed via the DFT/M06/6-311++G (d,p) calculations for 90 tetracoordinated borohydrides Li [L3B-H] taking into account the solvent effects via the optimization in MeCN and CH2Cl2 under SMD model. Obtained this way, the HDAMeCN values vary from 118.2 to 13.4 kcal/mol and correlate well with the Lewis acidity parameters (AN, HA and FA) of parent trigonal boranes (L3B). These data show numerically how the variation of the substituents at the boron atom allows the fine-tuning the B–H bond reactivity (reduction power) in the reactions involving hydride transfer as well as the selectivity of the reduction processes. The analysis of the data obtained shows that by varying the number of substituents and their nature, it is possible not only to change the properties of neutral trisubstituted boranes from highly electrophilic (represented by halogenide- and pseudohalogenide-boranes) to highly nucleophilic (exemplified by alkoxy-an amidoboranes), but also to repolarize the boron-bound hydrogen and make the proton transfer process more favourable than the hydride transfer. © 2018 Elsevier B.V

Comprehensive Insight into the Hydrogen Bonding of Silanes

The interaction of a set of mono-, di- and trisubstituted silanes with OH proton donors of different strength was studied by variable temperature (VT) FTIR and NMR spectroscopies at 190–298 K. Two competing sites of proton donors coordination: SiH and π-density of phenyl rings—are revealed for phenyl-containing silanes. The hydrogen bonds SiH⋅⋅⋅HO and OH⋅⋅⋅π(Ph) are of similar strength, but can be distinguished in the νSiH range: the νSiH⋅⋅⋅HO vibrations appear at lower frequencies while OH⋅⋅⋅π(Ph) complexes give Si–H vibrations shifted to higher frequency. The calculations showed the manifold picture of the noncovalent interactions in hydrogen-bonded complexes of phenylsilanes. As OH⋅⋅⋅HSi bonds are weak, the other noncovalent interactions compete in the stabilization of the intermolecular complexes. Still, the structural and electronic parameters of “pure” DHB complexes of phenylsilanes are similar to those of Et3SiH. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinhei

Oxidative Coupling of Anionic Abnormal N-Hetero-cyclic Carbenes: Efficient Access to Janus-Type 4,4'-Bis(2H-imidazol-2-ylidene)s

The oxidative coupling of anionic imidazol-4-ylidenes protected at the C2 position with [MnCp(CO)(2)] or BH3 led to the corresponding 4,4'-bis(2H-imidazol-2-ylidene) complexes or adducts, in which the two carbene moieties are connected through a single C-C bond. Subsequent acidic treatment of the later species led to the corresponding 4,4'-bis(imidazolium) salts in good yields. The overall procedure offers practical access to a novel class of Janus-type bis(NHC)s. Strikingly, the coplanarity of the two NHC rings within the mesityl derivative 4,4'-bis(IMes), favored by steric hindrance along with stabilizing intramolecular C-H center dot center dot center dot pi aryl interactions, allows the alignment of the pi-systems and, as a direct consequence, significant electron communication through the bis(carbene) scaffold