Changes in Tricarbastannatrane Transannular N–Sn Bonding upon Complexation Reveal Lewis Base Donicities

Abstract

Hypercoordinated complexes involving tricarbastannatrane cation [N(CHCHCH)Sn] with various Lewis bases are investigated in the gas and solution phases using a combination of infrared multiple photon dissociation (IRMPD) spectroscopy, NMR spectroscopy, and density functional theory calculations. Coordination is found to occur at the apical position leading to a pentacoordinated Sn center. Strongly electron donating Lewis bases disrupt the N···Sn transannular interaction and induce higher degrees of geometric distortion at the metal center than weakly donating Lewis bases, an effect that manifests as anharmonic shifts in the vibrational spectra. Once characterized in the gas phase, [N(CHCHCH)Sn(Lewis base)] structures were embedded in a dichloroethane polarizable continuum model to investigate solution phase properties. Calculated Sn NMR chemical shifts were found to be in good agreement with those measured experimentally, thus suggesting that the bonding properties of [N(CHCHCH)Sn] are essentially the same in the gas and solution phases.

Understanding Nontraditional Differential Mobility Behavior: A Case Study of the Tricarbastannatrane Cation, N(CH2CH2CH2)3Sn+

“…All computational results that were used for dispersion plot calculations are provided in the Supporting Information. As expected based on the measured dispersion plots and from the work of Simidzija et al, 25 solvent binding via the Sn center of the tricarbastannatrane cage is relatively strong for both ACE and ACN. Analogous calculations wherein the solvent molecule was bound to the N center indicate substantially reduced interactions with ACN and ACE owing predominantly to steric hindrance at the binding site and significantly poorer overlap between the solvent HOMO and cage LUMO (see Figure 2).…”

“…As can be seen in the middle and bottom panels of Figure3, the ACE-and ACN-modified environments yield clusters of tricarbastannatrane and a single solvent molecule. This result, which indicates that the DMS cell is acting as a pick-up cell for the solvent molecules, accords with expectations based on Simidzija's IRMPD work 25. This result is also noteworthy because ion−solvent complexes are typically not observed in hybrid triple quadrupole linear ion trap instruments; they are observed here owing to the relatively strong complexation between the Lewis basic solvent molecules and the Lewis acidic N(CH 2 CH 2 CH 2 ) 3 Sn + cation.…”

“…24 These species and other analogous complexes were subsequently studied via infrared multiple photon dissociation (IRMPD) spectroscopy. 25 This work demonstrated that ion−solvent complexation occurred at the vacant apical site of the Sn center via a large accepting lobe of the LUMO (see Figure 2).…”

“…In 2015, Kavoosi and Fillion published the synthesis and characterization of a variety of tricarbastannatrane-containing species, including several [N­(CH 2 CH 2 CH 2 ) 3 Sn + LB] + coordination complexes [Lewis Base (LB) = acetonitrile, THF, DACBO, diphenylacetylene] . These species and other analogous complexes were subsequently studied via infrared multiple photon dissociation (IRMPD) spectroscopy . This work demonstrated that ion–solvent complexation occurred at the vacant apical site of the Sn center via a large accepting lobe of the LUMO (see Figure ).…”

Preparation of Enantioenriched Alkylcarbastannatranes via Nucleophilic Inversion of Alkyl Mesylates for Use in Stereospecific Cross-Coupling Reactions

“…Building upon the pioneering work of Jurkschat and Vedejs, in 2013, our laboratory developed a Stille cross-coupling reaction of enantioenriched secondary alkylcarbastannatrane nucleophiles and aryl electrophiles (Figure ). − This method afforded arylation products in high yields and with high enantiospecificity. The unique reactivity of alkylcarbastannatranes is attributed to the selective labilization of its apical alkyl substituent as a consequence of the dative N–Sn interaction in the “atrane” tin backbone .…”