title: New Insight into the Nature of Bonding in the Dimers of Lappert's Stannylene and Its Ge Analogs: A Quantum Mechanical Study.
abstract: The strength and nature of the connection in Lappert's stannylene dimer ({Sn[CH(SiMe3)2]2}2) and its smaller analogs, simplified stannylenes, as well as similar Ge complexes were studied by means of DFT-D3 calculations, energy decomposition analysis (EDA), electrostatic potential (ESP), and natural population analysis. The trans-bent structure of the investigated molecules was rationalized by means of EDA, ESP, and molecular orbital (MO) analyses. The different ESPs for the monomers studied are a result of different hybridization of the Sn (Ge) atoms. The comparably strong stabilization in the largest and the smallest systems with a dramatically different substituent size is explained by the different nature of the binding between monomers. For all complexes, it has been found that the total attractive interaction is mostly provided by the electrostatic component (>50%), followed by orbital interaction and dispersion. In the largest molecule (Lappert's stannylene), the dispersion interaction plays a more significant role in stabilization and its magnitude is comparable to that of orbital interaction; on the other hand in the smallest molecule (SnH2), where bulky substituents are replaced by H only, the dispersion energy is less important and the E-E bond is more of a charge-transfer character, caused by donor-acceptor orbital interactions. The charge transfer in Ge dimers is greater than in the Sn ones due to shorter distances between monomers, which cause better ⟨HOMO/LUMO⟩ overlaps. The easier dimerization of Lappert's stannylene as compared to Kira's ({Sn[(Me3Si)2CHCH2CH2CH(SiMe3)2-κ(2)C,C']}) stannylene is explained by the different orientation of their substituents-asymmetry promotes dimerization.
authors.affiliation: Institute of Organic Chemistry and Biochemistry , Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic.|Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Palacký University , 771 46 Olomouc, Czech Republic.
authors.forename: Robert
authors.initials: R
authors.lastname: Sedlak
authors.affiliation: Institute of Organic Chemistry and Biochemistry , Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic.
authors.forename: Olga A
authors.initials: OA
authors.lastname: Stasyuk
authors.affiliation: Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, VU Amsterdam , De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
authors.forename: Célia
authors.initials: C
authors.lastname: Fonseca Guerra
authors.affiliation: Institute of Organic Chemistry and Biochemistry , Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Řezáč
authors.affiliation: Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice , Studentská 573, CZ-532 10, Pardubice, Czech Republic.
authors.forename: Aleš
authors.initials: A
authors.lastname: Růžička
authors.affiliation: Institute of Organic Chemistry and Biochemistry , Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic.|Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Palacký University , 771 46 Olomouc, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Hobza