Heptacoordinate Structures of Organotin Halides with Three Phosphine Donors: Halogen‐Substituent Effect on Geometry

Abstract

Structural studies were performed on heptacoordinate compounds of triorganotin halides {(o-Ph 2 P)C 6 H 4 } 3 SnX [X = F (1), Cl (3), Br (4), I (5)] with three phosphine donors. The fluorostannane (1) has an unusual heptacoordinate geometry, in which the three phosphine donors interact with the Sn center around the opposite coordination site of the Sn-F bond (a form). In contrast, the chloro (3) and bromo (4) analogues have highly distorted pentagonal-bipyramidal geometries (b form), while the iodo analogue (5) has a tricapped tetrahedral geometry (c form). Although both b and c forms have two phosphine donors coordinating to the Sn center around the opposite site of the C ipso atoms and one phosphine donor coordinating to [a]

Synthesis, Structure, and Bonding Properties of Hypercoordinate Triorganotin Compounds Featuring Three O→Sn Interactions

“…Elemental analyses were conducted using a J‐Science Lab JM‐10 or FISONS Instrument EA108 elemental analyzer. { o ‐(Ph 2 P)C 6 H 4 } 3 SnX (X=F [5a] ( 1 a ), Cl [5e] ( 1 b ), Me [19] ( 1 f )) and { o ‐(Ph 2 P)C 6 H 4 }Li⋅Et 2 O [25] were prepared as described in the literature.…”

“…For example, fluorostannane 1 a , bearing three phosphine donors, adopts an unusual heptacoordinate structure (tricapped trigonal pyramidal geometry), in which three lone pairs (LPs) of phosphines simultaneously interact with relatively low antibonding orbital of Sn−F bond [5a] . Contrarily, the chloro 1 b and bromo 1 c analogues of 1 a adopted a pentagonal pyramidal geometry, and the iodo 1 d and hydride 1 e analogues adopted a tricapped tetrahedral geometry [5e] . Note that more electronegative substituents, X, afforded more distorted structure (∑(CSnC)=358.23(7) ( 1 a , X=F), 346.58(15) ( 1 b , X=Cl), 347.19(17) (X=Br), 339.7(3) (X=I), 314.86(12) (X=H)), suggesting that the accumulated p character in Sn−X bonds (Bent's rule) [8] enabled access to highly distorted structures from the tetrahedral geometry.…”