Organo-Tricyanoborates as Tectons: Illustrative Coordination Polymers Based on Copper(I) Derivatives

The first systematic study on the use of tricyanoborates as ligands is presented. The tricyanoborates [RB(CN)3]-
(R = oct and Ph) can be prepared by direct cyanation of RBCl2 precursors as well as by thermolysis of the
corresponding isocyanides [RB(NC)3]-. The first organo-cyanogallates [RGa(CN)3]- (R = Bu, C6H2-2,4,6-Me3) were
prepared from the corresponding dichloride, the structure of Et4N[mesGa(CN)3] being confirmed crystallographically.
The reaction of equimolar [RB(CN)3]- (R = oct, Ph) and [Cu(MeCN)4]+ afforded two-dimensional polymers [RB(CN)3Cu(NCMe)]. The sheets arise via conjoined hexagonal B3Cu3(CN)6 rings with chair conformations. The reaction
of excess [PhB(CN)3]- and [Cu(MeCN)4]+ gives the polymer [K(18-crown-6)]{Cu[PhB(CN)3]2}. Treatment of
[PhB(CN)3]- with [Cu(PCy3)2(NCMe)x]PF6 gave the one-dimensional polymer [PhB(CN)3Cu(PCy3)2], wherein two of
the three BCN substituents are coordinated.