Structural insight into the magnesium borohydride - ethylenediamine solid-state Mg-ion electrolyte system.

A highly complex crystal structure of stoichiometric Mg5(en)6(BH4)10 was solved from single crystal synchrotron X-ray diffraction and confirmed by neutron powder diffraction (NPD) on isotopically substituted Mg(en)1.2(11BD4)2. We highlight the role of the amorphous Mg(BH4)2 in the reactivity of the Mg(BH4)2-en system and characterized a previously overlooked phase, Mg(en)2(BH4)2.

Effectiveness of the Fast Track Surgery Program for Patients with Planned Cholecystectomy.

PURPOSE: This study analyzed the effectiveness of minimizing surgical trauma, reducing the severity of the stress reaction, and restoring the normal functioning of the body after planned gallbladder operations under an enhanced recovery program. MATERIALS AND METHODS: This prospective comparison study included 30 patients from the surgical department of Irkutsk Clinical Hospital No. 1 who had been diagnosed with cholelithiasis in 2019-2020. All 30 patients completed the study and were randomly assigned to one of two groups: the FTS group (group I, n = 15) and the standard group (group II, n = 15). The comparison groups were statistically homogeneous in terms of preoperative parameters. All patients underwent prescribed surgeries. In the early and late postoperative period, there were no cases of mortality or significant complications. RESULTS: A comparison of the groups with respect to the effectiveness of treatment according to established criteria showed good treatment results for 13 (86.6%) patients in group I and 2 (13.3%) patients in group II (p = 0.016). The FTS treatment protocol was a significant predictor of treatment success (OR 3.1; 95% CI 0.2; 6.0; p = 0.033). CONCLUSION: The fast track surgery protocol gave superior results for surgical treatment in comparison with the standard protocol in patients with cholelithiasis.

The Reaction of Hydrogen Halides with Tetrahydroborate Anion and Hexahydro-closo-hexaborate Dianion.

The mechanism of the consecutive halogenation of the tetrahydroborate anion [BH4]- by hydrogen halides (HX, X = F, Cl, Br) and hexahydro-closo-hexaborate dianion [B6H6]2- by HCl via electrophile-induced nucleophilic substitution (EINS) was established by ab initio DFT calculations [M06/6-311++G(d,p) and wB97XD/6-311++G(d,p)] in acetonitrile (MeCN), taking into account non-specific solvent effects (SMD model). Successive substitution of H- by X- resulted in increased electron deficiency of borohydrides and changes in the character of boron atoms from nucleophilic to highly electrophilic. This, in turn, increased the tendency of the B-H bond to transfer a proton rather than a hydride ion. Thus, the regularities established suggested that it should be possible to carry out halogenation more selectively with the targeted synthesis of halogen derivatives with a low degree of substitution, by stabilization of H2 complex, or by carrying out a nucleophilic substitution of B-H bonds activated by interaction with Lewis acids (BL3).

Urinary System Iatrogenic Injuries: Problem Review.

INTRODUCTION: From May to December 2019, a literature review of the urinary system iatrogenic injury problem was performed. The most cited, representative articles in PubMed, Scopus, and WoS databases dedicated to this problem were selected. Urinary system iatrogenic injuries include ureter, bladder, urethra, and kidney traumas. It is widely thought that the main causes of such injuries are urological, obstetric, gynecological, and surgical operations on the retroperitoneal space, pelvis, or perineum. METHODS: The purpose of the study is to describe all aspects of the iatrogenic injure problem, under the established scheme and for each of the most damaged organs: the urethra, bladder, kidney, and ureter. The treatment of confirmed iatrogenic injuries largely depends on the period of its detection. Modern medical procedures provide conservative or minimally invasive treatment. An untimely diagnosis worsens the treatment prognosis. "Overlooked" urinary system trauma is a serious threat to society and a particular patient. Thus, incorrect or traumatic catheterization can lead to infection (RR 95%) and urethral stricture (RR ≥11-36%), and percutaneous puncture nephrostomy can cause the risk of functional renal parenchyma loss (median 5%), urinary congestion (7%), or sepsis (0.6-1.5%). RESULTS: Lost gain, profits, long-term and expensive, possibly multistage treatment, stress and depression, and the risks of suicide put a heavy financial, moral, and ethical burden on a person and society. Also, iatrogenic injury might have legal consequences. DISCUSSION/CONCLUSION: Thus, the significant problem of urinary tract iatrogenic injuries is still difficult to solve. There is a need to implement mandatory examining algorithms for patients at risk, as well as the multidisciplinary principle for all pelvic surgery.

Dichotomous Si-H Bond Activation by Alkoxide and Alcohol in Base-Catalyzed Dehydrocoupling of Silanes.

The activation of silanes in dehydrogenative coupling with alcohols under general base catalysis was studied experimentally (using multinuclear NMR, IR, and UV-visible spectroscopies) and computationally (at DFT M06/6-311++G(d,p) theory level) on the example of Ph4-nSiHn (n = 1-3) interaction with (CF3)2CHOH in the presence of Et3N. The effect of the phenyl groups' number and H- substitution by the electron-withdrawing (CF3)2CHO- group on Si-H bond hydricity (quantified as hydride-donating ability, HDA) and Lewis acidity of silicon atom (characterized by maxima of molecular electrostatic potential) was accessed. Our results show the coordination of Lewis base (Y = Me3N, ROH, OR-) leads to the increased hydricity of pentacoordinate hypervalent Ph4-nSi(Y)Hn complexes and a decrease of the reaction barrier for H2 release. The formation of tertiary complexes [Ph4-nSi(Y)Hn]···HOR is a critical prerequisite for the dehydrocoupling with alkoxides being ideal activators. The latter can be external or internal, generated by in situ HOR deprotonation. The mutual effect of tetrel interaction and dihydrogen bonding in tertiary complexes (RO-)Ph4-nSiHn···HOR leads to dichotomous activation of Si-H bond promoting the proton-hydride transfer and H2 release.

Thermodynamic Hydricity of Small Borane Clusters and Polyhedral closo-Boranes.

Thermodynamic hydricity (HDAMeCN) determined as Gibbs free energy (ΔG°[H]-) of the H- detachment reaction in acetonitrile (MeCN) was assessed for 144 small borane clusters (up to 5 boron atoms), polyhedral closo-boranes dianions [BnHn]2-, and their lithium salts Li2[BnHn] (n = 5-17) by DFT method [M06/6-311++G(d,p)] taking into account non-specific solvent effect (SMD model). Thermodynamic hydricity values of diborane B2H6 (HDAMeCN = 82.1 kcal/mol) and its dianion [B2H6]2- (HDAMeCN = 40.9 kcal/mol for Li2[B2H6]) can be selected as border points for the range of borane clusters' reactivity. Borane clusters with HDAMeCN below 41 kcal/mol are strong hydride donors capable of reducing CO2 (HDAMeCN = 44 kcal/mol for HCO2-), whereas those with HDAMeCN over 82 kcal/mol, predominately neutral boranes, are weak hydride donors and less prone to hydride transfer than to proton transfer (e.g., B2H6, B4H10, B5H11, etc.). The HDAMeCN values of closo-boranes are found to directly depend on the coordination number of the boron atom from which hydride detachment and stabilization of quasi-borinium cation takes place. In general, the larger the coordination number (CN) of a boron atom, the lower the value of HDAMeCN.

A multidisciplinary approach to urinary system iatrogenic injuries.

INTRODUCTION: Urinary system iatrogenic injuries appear because of urological, obstetric-gynecological, and surgical manipulations in the retroperitoneal space, pelvis, or perineum. The purpose of this research was to analyze and obtain knowledge about the issue of iatrogenic injuries, to apply injury prevention algorithms, and to assess multidisciplinary perspectives in modern surgery. MATERIAL AND METHODS: The research was interdisciplinary and consisted of several modules: a prospective, single-centre study of urinary system iatrogenic injuries (476 patients) along with four interregional and international procedural types of research. RESULTS: The analysis results indicate an extremely high significance of urinary system injuries evoking numerous negative consequences that are hard to eliminate. A comparative assessment of interdisciplinary interaction demonstrates the more effective interpretation of examination results, more comprehensive and credible clinical diagnosis, more qualitative evaluation of a patient's condition, more effective choice of initial treatment policy, and more satisfactory treatment in patients' opinion. The research allowed for the identification of a typical procedural mistake in the urethral catheter setting causing a high risk of urethra injuries followed by urethra strictures or consecutive infections of the urinary tract. CONCLUSIONS: More complicated treatment procedures cause a higher probability of urinary system iatrogenic injuries. The absence of unified algorithms and typical procedural mistakes cause such incidents. A partial solution to this issue could be found in a more profound interdisciplinary interaction in all treatment phases as well as in identifying and eliminating procedural mistakes.

Synthesis, structural properties and reactivity of ruthenocene-based pincer Pd(ii) tetrahydroborate.

Two novel ruthenocene-based pincer palladium tetrahydroborates were characterized by XRD, NMR and FTIR. The alcoholysis of Pd(ii) tetrahydroborate LPd(BH4) (L = κ3-[{2,5-(tBu2PCH2)2C5H2}Ru(C5H5)]) yields the dinuclear cationic Pd(ii) tetrahydroborate with the bridging BH4- ligand [(LPd)2(µ,η1,2:η1,2-BH4)]+. The bifurcate dihydrogen-bonded complexes are the active intermediates of the first proton transfer in the step-wise alcoholysis of LPd(BH4), yielding eventually [(LPd)2(µ,η1,2:η1,2-BH4)]+. According to the X-ray and DFT/M06 geometry analysis, the BH4- ligand in both palladium tetrahydroborates has a mixed coordination mode η1,2. The possibility of BH3-group abstraction from LPd(BH4) by an excess of organic base (THF, Py) with the formation of hydride LPdIIH is shown. This Pd(ii) hydride is a very reactive compound able to rapidly capture CO2 (ca. 15 min) converting into the formate complex LPdII(η1-OC(O)H). The hydrolysis of LPdH with subsequent CO2 insertion yields a hydrocarbonate complex LPdII(η1-OC(O)OH). The hydrocarbonate complex forms hydrogen-bonded dimers in the crystal due to hydrogen bonds between the OC(O)OH fragments.

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 Et3 SiH.

Ammonia Borane Dehydrogenation Catalyzed by (κ4-EP3)Co(H) [EP3 = E(CH2CH2PPh2)3; E = N, P] and H2 Evolution from Their Interaction with NH Acids.

Two Co(I) hydrides containing the tripodal polyphosphine ligand EP3, (κ4-EP3)Co(H) [E(CH2CH2PPh2)3; E = N (1), P (2)], have been exploited as ammonia borane (NH3BH3, AB) dehydrogenation catalysts in THF solution at T = 55 °C. The reaction has been analyzed experimentally through multinuclear (11B, 31P{1H}, 1H) NMR and IR spectroscopy, kinetic rate measurements, and kinetic isotope effect (KIE) determination with deuterated AB isotopologues. Both complexes are active in AB dehydrogenation, albeit with different rates and efficiency. While 1 releases 2 equiv of H2 per equivalent of AB in ca. 48 h, with concomitant borazine formation as the final "spent fuel", 2 produces 1 equiv of H2 only per equivalent of AB in the same reaction time, along with long-chain poly(aminoboranes) as insoluble byproducts. A DFT modeling of the first AB dehydrogenation step has been performed, at the M06//6-311++G** level of theory. The combination of the kinetic and computational data reveals that a simultaneous B-H/N-H activation occurs in the presence of 1, after a preliminary AB coordination to the metal center. In 2, no substrate coordination takes place, and the process is better defined as a sequential BH3/NH3 insertion process on the initially formed [Co]-NH2BH3 amidoborane complex. Finally, the reaction of 1 and 2 with NH-acids [AB and Me2NHBH3 (DMAB)] has been followed via VT-FTIR spectroscopy (in the -80 to +50 °C temperature range), with the aim of gaining a deeper experimental understanding of the dihydrogen bonding interactions that are at the origin of the observed H2 evolution.

Unusual Tri-, Hexa-, and Nonanuclear Cu(II) Cage Methylsilsesquioxanes: Synthesis, Structures, and Catalytic Activity in Oxidations with Peroxides.

Three types of unusual cagelike copper(II) methylsilsesquioxanes, namely, nona- [(MeSiO1.5)18(CuO)9] 1, hexa- [(MeSiO1.5)10(HO0.5)2(CuO)6(C12H8N2)2(MeSiO1.5)10(HO0.5)1.33(CH3COO0.5)0.67(CuO)6(C12H8N2)2] 2, [(MeSiO1.5)10(CuO)6(MeO0.5)2(C10H8N2)2] 3, and trinuclear [(MeSiO1.5)8(CuO)3(C10H8N2)2] 4, were obtained in 44%, 27%, 20%, and 16% yields, respectively. Nuclearity and structural fashion of products was controlled by the choice of solvent system and ligand, specifically assisting the assembling of cage. Structures of 1-4 were determined by single-crystal X-ray diffraction analysis. Compounds 1 and 4 are the first cage metallasilsesquioxanes, containing nine and three Cu ions, respectively. Product 1 is the first observation of nonanuclear metallasilsesquioxane ever. Unique architecture of 4 represents early unknown type of molecular geometry, based on two condensed pentamembered siloxane cycles. Topological analysis of metal clusters in products 1-4 is provided. Complex 1 efficiently catalyzes oxidation of alcohols with tert-butylhydroperoxide TBHP to ketones or alkanes with H2O2 to alkyl hydroperoxides in acetonitrile.

Cage-like Fe,Na-Germsesquioxanes: Structure, Magnetism, and Catalytic Activity.

A series of four unprecedented heterometallic metallagermsesquioxanes were synthesized. Their cage-like architectures have a unique type of molecular topology consisting of the hexairon oxo {Fe6 O19 } core surrounded in a triangular manner by three cyclic germoxanolates [PhGe(O)O]5 . This structural organization induces antiferromagnetic interactions between the FeIII ions through the oxygen atoms. Evaluated for this first time in catalysis, these compounds showed a high catalytic activity in the oxidation of alkanes and the oxidative formation of benzamides from alcohols.

Dihydrogen bond intermediated alcoholysis of dimethylamine-borane in nonaqueous media.

Dimethylamine-borane (DMAB) acid/base properties, its dihydrogen-bonded (DHB) complexes and proton transfer reaction in nonaqueous media were investigated both experimentally (IR, UV/vis, NMR, and X-ray) and theoretically (DFT, NBO, QTAIM, and NCI). The effects of DMAB concentration, solvents polarity and temperature on the degree of DMAB self-association are shown and the enthalpy of association is determined experimentally for the first time (-ΔH°assoc = 1.5-2.3 kcal/mol). The first case of "improper" (blue-shifting) NH···F hydrogen bonds was observed in fluorobenzene and perfluorobenzene solutions. It was shown that hydrogen-bonded complexes are the intermediates of proton transfer from alcohols and phenols to DMAB. The reaction mechanism was examined computationally taking into account the coordinating properties of the reaction media. The values of the rate constants of proton transfer from HFIP to DMAB in acetone were determined experimentally [(7.9 ± 0.1) × 10(-4) to (1.6 ± 0.1) × 10(-3) mol(-1)·s(-1)] at 270-310 K. Computed activation barrier of this reaction ΔG(‡theor)298 K(acetone) = 23.8 kcal/mol is in good agreement with the experimental value of the activation free energy ΔG(‡exp)270 K = 21.1 kcal/mol.

Dihydrogen bonding in complex (PP3)RuH(η(1)-BH4) featuring two proton-accepting hydride sites: experimental and theoretical studies.

Combining variable-temperature infrared and NMR spectroscopic studies with quantum-chemical calculations (density functional theory (DFT) and natural bond orbital) allowed us to address the problem of competition between MH (M = transition metal) and BH hydrogens as proton-accepting sites in dihydrogen bond (DHB) and to unravel the mechanism of proton transfer to complex (PP3)RuH(η(1)-BH4) (1, PP3 = κ(4)-P(CH2CH2PPh2)3). Interaction of complex 1 with CH3OH, fluorinated alcohols of variable acid strength [CH2FCH2OH, CF3CH2OH, (CF3)2CHOH (HFIP), (CF3)3COH], and CF3COOH leads to the medium-strength DHB complexes involving BH bonds (3-5 kcal/mol), whereas DHB complexes with RuH were not observed experimentally. The two proton-transfer pathways were considered in DFT/M06 calculations. The first one goes via more favorable bifurcate complexes to BHterm and high activation barriers (38.2 and 28.4 kcal/mol in case of HFIP) and leads directly to the thermodynamic product [(PP3)RuHeq(H2)](+)[OR](-). The second pathway starts from the less-favorable complex with RuH ligand but shows a lower activation barrier (23.5 kcal/mol for HFIP) and eventually leads to the final product via the isomerization of intermediate [(PP3)RuHax(H2)](+)[OR](-). The B-Hbr bond breaking is the common key step of all pathways investigated.

Dimerization mechanism of bis(triphenylphosphine)copper(I) tetrahydroborate: proton transfer via a dihydrogen bond.

The mechanism of transition-metal tetrahydroborate dimerization was established for the first time on the example of (Ph(3)P)(2)Cu(η(2)-BH(4)) interaction with different proton donors [MeOH, CH(2)FCH(2)OH, CF(3)CH(2)OH, (CF(3))(2)CHOH, (CF(3))(3)CHOH, p-NO(2)C(6)H(4)OH, p-NO(2)C(6)H(4)N═NC(6)H(4)OH, p-NO(2)C(6)H(4)NH(2)] using the combination of experimental (IR, 190-300 K) and quantum-chemical (DFT/M06) methods. The formation of dihydrogen-bonded complexes as the first reaction step was established experimentally. Their structural, electronic, energetic, and spectroscopic features were thoroughly analyzed by means of quantum-chemical calculations. Bifurcate complexes involving both bridging and terminal hydride hydrogen atoms become thermodynamically preferred for strong proton donors. Their formation was found to be a prerequisite for the subsequent proton transfer and dimerization to occur. Reaction kinetics was studied at variable temperature, showing that proton transfer is the rate-determining step. This result is in agreement with the computed potential energy profile of (Ph(3)P)(2)Cu(η(2)-BH(4)) dimerization, yielding [{(Ph(3)P)(2)Cu}(2)(µ,η(4)-BH(4))](+).