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In a recent communication (Angew. Chem. Int. Ed. 2024, 63, e202317312), Kalita et al. studied In4H+ system within the frame of single‐reference approximation (SRA) and found that the global energy minimum (1 a) adopted the singlet state and a planar tetracoordinate hydrogen (ptH), while the second lowest isomer (1 b) located 3.0 kcal/mol above 1 a and adopted the triplet state as well as non‐planar structure with a quasi‐ptH. They assessed the reliability of SRA by checking the T1‐diagnostic values of coupled cluster calculations. However, according to our multi‐configurational second‐order perturbation theory calculations at the CASPT2(12,13)/aug‐cc‐pVQZ (aug‐cc‐pVQZ‐PP for In) level, both 1 a and 1 b exhibit obvious multi‐referential characters, as reflected by their largest reference coefficients of 0.928 (86.1 %) and 0.938 (88.0 %), respectively. Moreover, 1 b is 5.05 kcal/mol lower than 1 a at this level, that is, what can be observed in In4H+ system is the quasi‐ptH. [ABSTRACT FROM AUTHOR]

Boron has been found to be able to form multiple bonds with lead. To probe Pb–B bonding, here we report an investigation of three Pb-doped boron clusters, PbB2−, PbB3O−, and PbB4O2−, which are produced by a laser ablation cluster source and characterized by photoelectron spectroscopy and ab initio calculations. The most stable structures of PbB2−, PbB3O−, and PbB4O2− are found to follow the formula, [PbB2(BO)n]− (n = 0–2), with zero, one, and two boronyl ligands coordinated to a triangular and aromatic PbB2 core, respectively. The PbB2− cluster contains a B＝B double bond and two Pb–B single bonds. The coordination of BO is observed to weaken Pb–B bonding but strengthen the B＝B bond in [PbB2(BO)n]− (n = 1, 2). The anionic [PbB2(BO)2]− and its corresponding neutral closed-shell [PbB2(BO)2] contain a B≡B triple bond. A low-lying Y-shaped isomer is also observed for PbB4O2−, consisting of a central sp2 hybridized B atom bonded to two boronyl ligands and a PbB unit. [ABSTRACT FROM AUTHOR]

Doxazosin used in benign prostatic hyperplasia has the side effects of causing hypotension and the risk of heart failure. The 3 targets of [α.sub.1A]-adrenoceptors (in the prostate), [α.sub.1D]-adrenoceptors (in the aorta), and an unknown mechanism (in the heart) are involved, respectively. We hypothesized that there is a chiral recognition of doxazosin enantiomers in the 3 targets. Using isolated rat aorta ([α.sub.1D]-adrenoceptors) and rabbit prostate ([α.sub.1A]-adrenoceptors), we examined [pA.sub.2] and [pK.sub.B] values of doxazosin enantiomers. We observed chronotropic and inotropic effects of doxazosin enantiomers in isolated rat and rabbit heart tissues. (-)Doxazosin and (+)doxazosin produced a shift to the right of concentration-contraction curves for noradrenalin (aorta) and phenylephrine (prostate smooth muscle). The [pA.sub.2] value of (-)doxazosin (8.625 [+ or -] 0.053) was smaller than (+)doxazosin (9.503 ± 0.051) in rat aorta, but their [pK.sub.B] values in rabbit prostate were the same. In rat and rabbit heart tissues, (+)doxazosin (3-30 (µmol x [L.sup.-1]) significantly decreased atrial rate, and produced negative inotropic effects; however, (-)doxazosin did not affect the atrial rate, and produced positive inotropic effects in the atria. Thus, the chiral carbon atom of doxazosin does not affect its activity at the therapeutic target of [α.sub.1A]-adrenoceptors in the prostate, but significantly changes its blocking activity against [α.sub.1D]-adrenoceptors in the aorta, and produces opposite inotropic effects in the atria via an [α.sub.1]-adrenoceptor-independent mechanism. Key words: doxazosin, enantiomer, prostate, aorta, heart. La doxazosine utilisee dans l'hyperplasie benigne de la prostate exerce un effet secondaire hypotenseur et un augmente le risque d'insuffisance cardiaque, et trois cibles des recepteurs [α.sub.1A]-adrenergiques (dans la prostate), [α.sub.1D]-adrenergiques (dans l'aorte) ainsi qu'un mecanisme inconnu (dans le coeur) sont respectivement impliques. Nous avons verifie l'hypothese d'une reconnaissance chirale des enantiomeres de la doxazosine par les trois cibles. Nous avons examine les valeurs de [pA.sub.2] et [pK.sub.B] des enantiomeres de la doxazosine sur l'aorte de rat isolee (recepteurs [α.sub.1D]-adrenergiques) et la prostate de lapin (recepteurs [α.sub.1A]-adrenergiques). Nous avons observe les effets chronotopes et inotropes des enantiomeres de la doxazosine sur les tissus cardiaques isoles du rat et du lapin. La (-)doxazosine et la (+)doxazosine deplacaient vers la droite les courbes de concentration-contraction de la noradrenaline (aorte) et de la norepinephrine (muscle lisse de la prostate). La valeur de [pA.sub.2] de la (-)doxazosine (8,625 [+ ou -] 0,053) etait inferieure a celle de la (+)doxazosine (9,503 [+ ou -] 0,051) dans l'aorte de rat, mais leurs valeurs de pKB etaient les memes dans la prostate de lapin. Dans les tissus cardiaques de rat et de lapin, la (+)doxazosine (3-30 (µmol x [L.sup.-1]) diminuait significativement le rythme atrial et exercait des effets inotropes negatifs sur l'atrium ; cependant, la (-)doxazosine n'affectait pas le rythme atrial et exercait des effets inotropes positifs sur l'atrium. Le carbone chiral de la doxazosine n'affecte pas son activite comme cible therapeutique des recepteurs [α.sub.1A]-adrenergiques dans la prostate mais change significativement son activite bloquante envers les recepteurs [α.sub.1A]-adrenergiques dans l'aorte et exerce des effets inotropes opposes dans l'atrium par l'intermediaire d'un mecanisme independant des recepteurs [α.sub.1]-adrenergiques. Mots-cles: doxazosine, enantiomere, prostate, aorte, coeur. [Traduit par la Redaction], Introduction (±)Doxazosin ((±)DOX), a quinazoline based compound, is a long lasting inhibitor of a adrenoceptors that is widely used in the treatment of benign prostatic hyperplasia/lower urinary tract symptoms (LUTS/BPH) [...]

Despite its electron deficiency, boron can form multiple bonds with a variety of elements. However, multiple bonds between boron and main-group metal elements are relatively rare. Here we report the observation of boron-lead multiple bonds in PbB2O– and PbB3O2–, which are produced and characterized in a cluster beam. PbB2O– is found to have an open-shell linear structure, in which the bond order of B☱Pb is 2.5, while the closed-shell [Pb≡B–B≡O]2– contains a B≡Pb triple bond. PbB3O2– is shown to have a Y-shaped structure with a terminal B = Pb double bond coordinated by two boronyl ligands. Comparison between [Pb≡B–B≡O]2–/[Pb=B(B≡O)2]– and the isoelectronic [Pb≡B–C≡O]–/[Pb=B(C≡O)2]+ carbonyl counterparts further reveals transition-metal-like behaviors for the central B atoms. Additional theoretical studies show that Ge and Sn can form similar boron species as Pb, suggesting the possibilities to synthesize new compounds containing multiple boron bonds with heavy group-14 elements. Despite its electron deficiency, boron can form multiple bonds with a variety of elements, but such bonds between boron and main-group metal elements are relatively rare. Here, the authors characterize boron–lead multiple bonds in PbB2O- and PbB3O2- produced by laser vaporization. [ABSTRACT FROM AUTHOR]

Boron allotropes are known to be predominately constructed by icosahedral B12 cages, while icosahedral-B12 stuffing proves to effectively improve the stability of fullerene-like boron nanoclusters in the size range between B98–B102. However, the thermodynamically most stable core-shell borospherenes with a B12 icosahedron at the center still remains unknown. Based on the structural motif of D5h C70 and extensive first-principles theory calculations, we predict herein the high-symmetry C5v B111+ (3) which satisfies the Wade's n+1 and n+2 skeletal electron counting rules exactly and the approximately electron sufficient Cs B111 (4), Cs B112 (5), Cs B113 (6), and Cs B114 (7) which are the most stable neutral core-shell borospherenes with a B12 icosahedron at the center reported to date in the size range between B68–B130, with Cs B112 (5) being the thermodynamically most favorite species in the series. Detailed orbital and bonding analyses indicate that these spherically aromatic species all contain a negatively charged icosahedral B122− core at the center which exhibits typical superatomic behaviors in the electronic configuration of 1S21P61D101F8, with its dangling valences saturated by twelve radial B-B 2c-2e σ bonds between the B12 inner core and the B70 outer shell. The infrared (IR) and Raman spectra of the concerned species are computationally simulated to facilitate their future characterizations. [ABSTRACT FROM AUTHOR]

The newly discovered cage-like borospherene D2d B40 with two η6-B6 hexagons and four η7-B7 heptagons on the surface may serve as an effective multi-dentate ligand to coordinate transition metals. Based upon extensive density functional theory calculations, we present herein the possibility of the exohedral complex series (C6H6Cr)n&B40 (n = 1–6) with n Cr centres sandwiched between the central η6/7-B40 unit and n planar η6-C6H6 ligands. C6H6Cr fragments in (C6H6Cr)n&B40 occupy the η6-B6 hexagonal coordination site atop the B40 cage first, the four neighboring η7-B7 heptagons on the waist next, and finally the η6-B6 hexagon at the bottom, forming a multinuclear complex series effectively stabilized by n C6H6Cr fragments. The two η6-B6 hexagons and four η7-B7 heptagons on the spherical surface of B40 can be practically viewed as six independent coordination sites to coordinate Cr centers with almost the same coordination energies. Detailed bonding analyses indicate that the eclipsed C2v C6H6Cr&B40 (1-1) possesses a coordination bonding pattern similar to that of dibenzenechromium, with the B40 ligand inheriting the σ + π double delocalization bonding pattern of the parent borospherene. The IR, Raman, and UV–vis absorption spectra of C2v C6H6Cr&B40 (1-1) are theoretically simulated to facilitate its future experimental characterization. [ABSTRACT FROM AUTHOR]

As the first all-boron fullerene observed in experiments, cage-like borospherene B40 has attracted considerable attention in recent years. However, B40 has been proved to be chemically reactive and tends to coalesce with one another via the formation of covalent bonds. We explore herein the possibility of low-dimensional functional networks of B40 with effective transition-metal intercalations. We find that the four equivalent B7 heptagons on the waist of each B40 can serve as effective ligands to coordinate various transition metal centers in exohedral motifs. The intercalated metal atoms entail these networks with a variety of intriguing properties. The two-dimensional (2D) Cr2B40 network is a ferromagnetic metal while the 2D Zn2B40 network becomes semiconducting. In contrast, other 2D M2B40 (M = Sc, Ti, V, Mn, Fe, Co, Ni and Cu) networks and 1D CrB40 belong to nonmagnetic metals. The 3D Cr3B40 network is a magnetic metal. This work presents the viable possibility of assembling Mn&B40 metalloborospherenes into stable functional nanomaterials via effective transition-metal intercalations with potential applications in electronic and spintronic devices. [ABSTRACT FROM AUTHOR]

Inspired by recent discoveries of alkaline-earth octacarbonyls and based on extensive first-principles theory investigations, we predict herein the possibility of perfect cube-like alkali octacarbonyls M(CO)8− (Oh, 3A1g) (1) (M = K, Rb) which satisfy the 18-electron rule in an octacoordinate cubic field with (n − 1)d-orbital participation of alkali metal center playing an important role in M–CO coordination interaction. The slightly elongated neutral M(CO)8 (D4h, 2B1g) (3) turn out to be similar with the experimentally observed Ba(CO)8+ monocation in an octacoordinate tetragonal field. Detailed orbital analyses indicate that, similar to neutral alkaline-earth octacarbonyls, M(CO)8− monoanions possess the superatomic electronic configuration of S2P6D8F2, with the alkali–CO coordination interaction mainly originating from M(dπ) → (CO)8(π*) backdonations which result in strong red shifts of the C–O stretching frequencies relative to free CO. [ABSTRACT FROM AUTHOR]

Based on detailed bonding analyses on the fluxional behaviors of planar B19−, tubular Ta@B20−, and cage‐like B39−, we propose the concept of fluxional bonds in boron nanoclusters as an extension of the classical localized bonds and delocalized bonds in chemistry. © 2018 Wiley Periodicals, Inc. Detailed bonding analyses on fluxional boron nanoclusters suggest the existence of fluxional bonds in electron‐deficient systems with low energy barriers as an extension of the classical localized bonds and delocalized bonds in chemistry. [ABSTRACT FROM AUTHOR]

Transition-metal-doped boron clusters have received considerable attention in recent years. The experimentally observed planar or quasi-planar C2h B10(I), C2v B11−(II), C3v B12(III), and C2v B13+ (IV) are known to be boron analogs of benzene. Extensive global minimum searches and first-principles theory investigations performed herein indicate that doping these aromatic boron clusters with a nickel atom generates the closed-shell half-sandwich complexes C2v NiB10(1,1A1), Cs NiB11−(2, 1A′), C3v NiB12(3, 1A1), and Cs NiB13+ (4, 1A′) which are all well-defined global minima of the systems with the coordination numbers of CN = 10, 11, 12, and 13, respectively. Detailed bonding analyses indicate that these Ni-doped boron complexes are effectively stabilized by coordination interactions between the Ni center and aromatic Bn−/0/+ ligands (n = 10-13) and follow the universal coordination bonding pattern of σ plus π double delocalization. Molecular dynamics simulations show that, among these complex clusters, NiB11−(2) behaves like a Wankel motor at room temperature with the B3 inner wheel rotating almost freely inside the quasi-rotating B8 outer bearing in a concerted mechanism, revealing typical bonding fluctuations/fluxionalities in a molecular motor due to thermal vibrations. The IR, Raman and electronic spectra of the concerned species are computationally simulated to facilitate their experimental characterizations. [ABSTRACT FROM AUTHOR]