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

Abstract

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(CN3] 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.

Preparation and Characterization of Group 13 Cyanides

“…Two C‐Ga‐C angles are slightly widened to 111.41(7)°, while the remaining four C‐Ga‐C angles are slightly contracted to 108.51(3)°. The observed Ga−C distance of 1.970(1) Å in the [PPh 4 ][Ga(CN) 4 ] salt is significantly shorter than those reported for Li[Ga(CN) 4 ] (2.021(5)/2.00(1) Å), [(py) 2 Ga(CN) 3 ] (1.991(4) Å), and [Et 4 N][mesGa(CN) 3 ] (2.004(3) Å) . The observed C−N distance of 1.145(2) Å in [PPh 4 ](Ga(CN) 4 ] is significantly longer than those of 1.07(1) Å reported for Li[Ga(CN) 4 ] and 1.075(5) Å reported for [(py) 2 Ga(CN) 3 ], but is in good agreement with that in open framework [Ga(CN) 3 ] (1.148(1) Å) …”

“Umpolung” at Boron by Reduction of [B(CN)4]− and Formation of the Dianion [B(CN)3]2−

“…À , [34,35] [HB(CN) 2 (C{NH} 2 )] 2À [36] (Table S1 and Figure S2 in 4 OH] is formed; [37] see the NMR spectroscopy data in Table S2 and structural data in Table S1 and Figure S3 in Table 2 with data calculated for the free dianion (for Raman spectra of the Li and Na salts, see There are seven Raman-active (all observed) and six IRactive (four observed) bands. The vibrational spectrum is disturbed by Fermi resonances in the regions around 2030 and 1100 cm À1 , and the E modes (n 6 , n 7 , n 9 , n 10 ) are split into two components.…”

Cyanohydridoborate Anions: Synthesis, Salts, and Low‐Viscosity Ionic Liquids

“…The syntheses of salts of 2 and 3 known, so far, are summarized in Scheme . In 1983 the first syntheses for salts of both anions were reported . Na 3 ⋅2 dioxane was obtained starting from Na[BH 4 ] and Hg(CN) 2 .…”

“…AgCN was applied as an alternative CN source and reacted with Me 2 S⋅BH n Br 3− n ( n= 1, 2) to give the corresponding silver isocyanohydridoborates Ag[BH n (NC) 4− n ] . These silver salts were converted into Na[BH n (NC) 4− n ] with sodium metal in the presence of benzophenone or in case of Ag[BH(NC) 3 ] sodium sulfide was used, as well . The isocyanohydridoborate anions [BH n (NC) 4− n ] − were isomerized into the corresponding cyanohydridoborate anions 2 and 3 by refluxing in dibutyl ether (Scheme ) .…”

“…These silver salts were converted into Na[BH n (NC) 4− n ] with sodium metal in the presence of benzophenone or in case of Ag[BH(NC) 3 ] sodium sulfide was used, as well . The isocyanohydridoborate anions [BH n (NC) 4− n ] − were isomerized into the corresponding cyanohydridoborate anions 2 and 3 by refluxing in dibutyl ether (Scheme ) . More convenient approaches to dicyanodihydridoborates have been developed in 1984 and 1999 .…”