Synthetic Modification of Acyclic Bent Allenes (Carbodicarbenes) and Further Studies on Their Structural Implications and Reactivities

The paper describes the synthetic development of Bertrand-type acyclic carbodicarbene scaffolds derived from an unsymmetrical bis­(benzimidazol-2-yl)­methane bearing two sterically demanding pendant arms, isopropyl (<b>6a</b>) or cyclohexyl (<b>6b</b>). X-ray crystallographic analysis shows that the impact of these pendant arms on the overall structural parameters of carbodicarbenes is minimal. The chemical reactivity of the carbodicarbenes was evaluated with iodomethane to afford compound <b>7</b>, illustrating its nucleophilic properties. Finally, experiments were also undertaken to investigate the coordination ability of carbodicarbene toward the formation of rhodium carbonyl (<b>10</b>) and palladium allyl complexes (<b>11</b>). The crystal structures of the metal complexes have been determined, revealing that their metal–carbene distances are elongated only slightly, this fact was rationalized on the basis of geometrical steric considerations with regard to the ligand

Synthetic Modification of Acyclic Bent Allenes (Carbodicarbenes) and Further Studies on Their Structural Implications and Reactivities

The paper describes the synthetic development of Bertrand-type acyclic carbodicarbene scaffolds derived from an unsymmetrical bis­(benzimidazol-2-yl)­methane bearing two sterically demanding pendant arms, isopropyl (<b>6a</b>) or cyclohexyl (<b>6b</b>). X-ray crystallographic analysis shows that the impact of these pendant arms on the overall structural parameters of carbodicarbenes is minimal. The chemical reactivity of the carbodicarbenes was evaluated with iodomethane to afford compound <b>7</b>, illustrating its nucleophilic properties. Finally, experiments were also undertaken to investigate the coordination ability of carbodicarbene toward the formation of rhodium carbonyl (<b>10</b>) and palladium allyl complexes (<b>11</b>). The crystal structures of the metal complexes have been determined, revealing that their metal–carbene distances are elongated only slightly, this fact was rationalized on the basis of geometrical steric considerations with regard to the ligand

The Elusive Three-Coordinate Dicationic Hydrido Boron Complex

The formation of a hitherto unknown three-coordinate dicationic hydrido boron complex is described. Interestingly, supporting ligand carbodicarbene gave unprecedented reaction with BH₃ without using more highly electrophilic Lewis acid precursors. Spectroscopic, crystallographic, and computational analysis was performed to understand the electronic features of these species

The Elusive Three-Coordinate Dicationic Hydrido Boron Complex

The formation of a hitherto unknown three-coordinate dicationic hydrido boron complex is described. Interestingly, supporting ligand carbodicarbene gave unprecedented reaction with BH₃ without using more highly electrophilic Lewis acid precursors. Spectroscopic, crystallographic, and computational analysis was performed to understand the electronic features of these species

The Regioselective Switch for Amino-NHC Mediated C–H Activation of Benzimidazole via Ni–Al Synergistic Catalysis

We have disclosed a new mode of a chemically regioselective switch for C–H bond functionalization of benzimidazole derivatives via a cooperative effect invoked by Ni–Al bimetallic catalysis to create a steric requirement for obtaining the linear product of styrene insertion. Yet, excluding the AlMe₃ cocatalyst switches the reaction toward branch selectivity

Cerebral white matter burden is linked to cognitive function in patients undergoing hemodialysis

Chronic kidney disease is related to neurodegeneration and structural changes in the brain which might lead to cognitive decline. The Fazekas scale used for assessing white matter hyperintensities (WMHs) was associated with poor cognitive performance. Therefore, this study investigated the associations between the mini-mental status examination (MMSE), Montreal cognitive assessment (MoCA), cognitive abilities screening instrument (CASI), and Fazekas scale in patients under hemodialysis (HD). The periventricular (PV) WMHs and deep WMHs (DWMHs) in brain magnetic resonance images of 59 patients under dialysis were graded using the Fazekas scale. Three cognition function tests were also performed, then multivariable ordinal regression and logistic regression were used to identify the associations between cognitive performance and the Fazekas scale. There were inverse associations between the three cognitive function tests across the Fazekas scale of PVWMHs (p = .037, .006, and .008 for MMSE, MoCA, and CASI, respectively), but the associations were attenuated in the DWMHs group. In CASI, significant differences were identified in short-term memory, mental manipulation, abstract thinking, language, spatial construction, and name fluency in the PVWMHs group. However, DWMHs were only significantly correlated with abstract thinking and short-term memory. An inverse correlation existed between the Fazekas scale, predominantly in PVWMHs, and cognition in patients undergoing HD. The PVWMHs were associated with cognitive performance assessed by MMSE, MoCA, and CASI, as well as with subdomains of CASI such as memory, language and name fluency in patients undergoing HD. An inverse correlation existed between the Fazekas scale and cognition in patients undergoing hemodialysis, predominantly in periventricular white matter hyperintensities. The periventricular white matter hyperintensities were associated with cognitive performance assessed by mini-mental status examination (MMSE), Montreal cognitive assessment (MoCA), cognitive abilities screening instrument (CASI), as well as with subdomains of CASI such as memory, language and name fluency in patients undergoing HD.</p

Carbodicarbenes: Unexpected π‑Accepting Ability during Reactivity with Small Molecules

An investigation of carbodicarbenes, the less explored member of the carbenic complex/ligand family has yielded unexpected electronic features and concomitant reactivity. Observed 1,2-addition of E–H bonds (E = B, C, Si) across the carbone central carbon and that of the flanking N-heterocyclic carbene (NHC) fragment, combined with single-crystal X-ray studies of a model Pd complex strongly suggests a significant level of π-accepting ability at the central carbon of the NHC moiety. This feature is atypical of classic NHCs, which are strong σ-donors, with only nominal π-accepting ability. The unanticipated π-acidity is critical for engendering carbodicarbenes with reactivity more commonly observed with frustrated Lewis pairs (FLPs) rather than the more closely related NHCs and cyclic (alkyl)­(amino)­carbenes (CAACs)