Dative Bonding in Quasimetallatranes Containing Group 15 Donors (Y = N, P, and As) and Group 14 Acceptors (M = Si, Ge, Sn, and Pb).

Metallatranes and their analogous fused ring [3.3.0] bicyclic compounds, quasimetallatranes, have emerged as fascinating molecular systems with intriguing structural, bonding, and conformational properties. We present a comprehensive investigation aimed at unraveling the nature of dative bonding and exploring the conformational flexibility of these compounds. We extensively characterize the dative bond between the metal center and the electron pair donor, using a range of modeling techniques. Our analyses involve structural optimizations, molecular orbital examinations, and covalency ratio calculations, which provide a thorough understanding of the bonding interactions responsible for the stability of these systems. The results confirmed the presence of dative bonds, supported by the close proximity between the metal and the electron-donating group, and the observation of overlapping electron density. Our studies reveal a correlation between the size of the electron-donor and the coordinating metal atom, and the strength of the dative interaction, as indicated by the bond length and the Wiberg bond indices. This bond strength, in turn, influences the conformational preferences adopted by these compounds. This investigation sheds light on the fundamental aspects of the fused ring [3.3.0] bicyclic quasimetallatrane compounds and offers valuable insights into their unique properties.