title: Synthesis, X-ray diffraction studies, and DFT calculations on hexacoordinated germanium derivatives: the case of germaspirobis(ocanes).
abstract: Synthesis of the title compounds, viz. [RN(CH2CHR'O)2]2Ge (1, R = Me, R' = H; 2, R = Me, R' = Ph; 3, R = Ph, R' = H), by the reaction of 2 equiv of corresponding dialkanolamines RN(CH2CHR'OH)2 (4, R = Me, R' = H; 5, R = Me, R' = Ph; 6, R = Ph, R' = H) with (AlkO)4Ge is reported. Composition and structures of all novel compounds were established by 1H and 13C NMR spectroscopy and mass spectrometry as well as elemental analysis data. The single-crystal X-ray diffraction of 2 has clearly indicated the presence of two transannular interactions Ge<--N in the compound. N atoms are cis-orientated. The compound 3 possesses long Ge...N distances. The structural data obtained from geometry optimizations by DFT calculations on 1-3 reproduces experimental results. Both cis- and trans-isomers were studied, and cis-configuration was found to be more thermodynamically stable for all three compounds. The transition states for possible cis <--> trans rearrangement processes in 1-3 were calculated. The properties of the Ge-O and Ge<--N bonds in 1-3 were analyzed by the AIM approach. The interactions between the Ge atom and N atoms as well as O atoms possess predominantly ionic character.
authors.affiliation: Chemistry Department, Moscow State University, B-234, Leninskie Gory, 119899 Moscow, Russia. sergej@org.chem.msu.su
authors.forename: Sergey S
authors.initials: SS
authors.lastname: Karlov
authors.forename: Elmira Kh
authors.initials: EKh
authors.lastname: Lermontova
authors.forename: Maxim V
authors.initials: MV
authors.lastname: Zabalov
authors.forename: Anastasia A
authors.initials: AA
authors.lastname: Selina
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Churakov
authors.forename: Judith A K
authors.initials: JA
authors.lastname: Howard
authors.forename: Mikhail Yu
authors.initials: MY
authors.lastname: Antipin
authors.forename: Galina S
authors.initials: GS
authors.lastname: Zaitseva