π-Bonding and the Lone Pair Effect in Multiple Bonds between Heavier Main Group Elements

Electron-precise coordination modes of boron-centered ligands.

Recent years have seen rapid advances in the chemistry of small molecules containing electron-precise boron-boron bonds. This Review provides an overview of the latest methods for the controlled synthesis of B-B single and multiple bonds as well as the ever-expanding range of reactivity displayed by B-B multiple bonds.

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Formation and Reactivity of Electron-Precise B-B Single and Multiple Bonds.

The study of main-group molecules that behave and react similarly to transition-metal (TM) complexes has attracted significant interest in recent decades. Most notably, the attractive idea of replacing the all-too-often rare and costly metals from catalysis has motivated efforts to develop main-group-element-mediated reactions. Main-group elements, however, lack the electronic flexibility of TM complexes that arises from combinations of empty and filled d orbitals and that seem ideally suited to bind and activate many substrates. In this review, we look at boron, an element that despite its nonmetal nature, low atomic weight, and relative redox staticity has achieved great milestones in terms of TM-like reactivity. We show how in interelement cooperative systems, diboron molecules, and hypovalent complexes the fifth element can acquire a truly metallomimetic character. As we discuss, this character is powerfully demonstrated by the reactivity of boron-based molecules with H2, CO, alkynes, alkenes and even...

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Metallomimetic Chemistry of Boron

Boron compounds are widely used in a range of tribological applications such as friction modifiers, antioxidants, antiwear additives, and in many cases as environmentally friendly lubricants. The chemical nature and structure of boron compounds provide multifunctionality. They are used as (1) solid lubricants such as boric acid and hexagonal boron nitride, (2) liquid lubricants such as ionic liquids, (3) lubricant additives such as borate derivatives of various organic and inorganic compounds, and (4) coatings such as cubic boron nitride and different metal borides. Boron is also one of the most favorable elements for coatings and thin films in biotribological and biomedical applications. This review outlines the growing role of boron in lubrication over the past several decades, summarizes the main findings, and identifies future challenges related to boron chemistry.

Boron in tribology: from Borates to ionic liquids

A novel approach to an oxoborane and its Lewis base complex

Formation of a borylene by photolysis of an overcrowded bis(methylseleno)borane

Synthesis, Structure, and Reactions of the First Stable Dimercaptoborane

The prevalence of umbilical cord cysts at 7-13 weeks' gestation is approximately 3%. More than 20% of such cases are complicated by structural defects and/or chromosomal abnormalities such as trisomy 18. These cysts usually have a single cavity and are 5 cm) in a patient with a normal karyotype, 46XY. These anomalies were diagnosed by fetal ultrasonography. However, the cyst was difficult to diagnose as an umbilical cord pseudocyst because it was very large and multilobulated. At 38.5 weeks of gestation, the patient was delivered by Cesarean section. The cyst was resected, and the omphalocele was closed by staged surgeries. Pathologic diagnosis of the cyst was the degeneration of Wharton's jelly. This diagnosis was made by the absence of epithelial lining inside the cyst wall, since the existence of epithelial cells correlates with true cysts.

Mitsuhiro Ito

Papers

A novel approach to an oxoborane and its Lewis base complex

Formation of a borylene by photolysis of an overcrowded bis(methylseleno)borane

Synthesis, Structure, and Reactions of the First Stable Dimercaptoborane

Omphalocele associated with a large multilobular umbilical cord pseudocyst.

Formation and reactions of a thioxoborane, a novel boron-sulfur double-bond compound