Jacob S. Alexander

Not Just Heavy “Grignards”: Recent Advances in the Organometallic Chemistry of the Alkaline Earth Metals Calcium, Strontium and Barium

Since their initial development in the early 1900’s, Grignard reagents have proven to be immensely useful and are among the most common organometallic reagents. The nature of the reagents in solution is complex and depends on substituents, solvent, concentration and temperature. Despite continuing questions about their solid state and solution composition and conformation, organomagnesium reagents find new applications continually. In contrast, little information about the heavier alkaline earth organometallic compounds RMX and R2M (R = alkyl, aryl; M = Ca, Sr, Ba, X = halide) exists. High reactivity due to the predominantly ionic character of the metal-ligand bond and increased lability complicates synthetic access. Recent interest in the organometallic chemistry of the alkaline earth metals calcium, strontium and barium has been sparked by the realization that heavy alkaline earth metal organometallics play unique roles in synthetic applications, such as polymerization initiators and as reagents to modify polymers. As a result, the organometallic chemistry of calcium, strontium and barium has received significant attention over the last few years. This article summarizes recent results in this emerging area of chemistry. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Barium Triphenylmethanide: An Examination of Anion Basicity

Differences in anion basicity seem to be key for the formation of the first charge-separated barium triphenylmethanide versus a novel heteroleptic vinyl ether which results from cleavage of the attendant [18]crown-6. Ba: green; O: red; P: yellow; N: blue.

When VSEPR Fails: Experimental and Theoretical Investigations of the Behavior of Alkaline‐Earth‐Metal Acetylides

The synthesis, structural, and spectral characterization as well as a theoretical study of a family of alkaline-earth-metal acetylides provides insights into synthetic access and the structural and bonding characteristics of this group of highly reactive compounds. Based on our earlier communication that reported unusual geometry for a family of triphenylsilyl-substituted alkaline-earth-metal acetylides, we herein present our studies on an expanded family of target derivatives, providing experimental and theoretical data to offer new insights into the intensively debated theme of structural chemistry in heavy alkaline-earth-metal chemistry.

(1R,2S)-(+)-cis-1-Methoxycarbonyl-2-methylcyclobutane

An X-ray crystallographic structure determination for the related (R)-(−)-2-phenylglycinol derived amide demonstrates that (+)-cis-1-methoxycarbonyl-2-methylcyclobutane is the (1R,2S) isomer.