Inorganic Supramolecular Host Architectures: [(M@18c6)2][TlI4]·2H2O, M = 0.5 Tl, (NH4,NH3), (H3O,H2O)

Easy Access to Versatile Catalytic Systems for C-H Activation and Reductive Amination Based on Tetrahydrofluorenyl Rhodium(III) Complexes

On the basis of the 1,2,3,4-tetrahydrofluorenyl ligand, a simple approach was developed to new effective rhodium catalysts for the construction of C-C and C-N bonds. The halide compounds [(η⁵ -tetrahydrofluorenyl)RhX₂ ]₂ (2 a: X=Br; 2 b: X=I) were synthesized by treatment of the bis(ethylene) derivative (η⁵ -tetrahydrofluorenyl)Rh(C₂ H₄ )₂ (1 a) with halogens. An analogous reaction of the cyclooctadiene complex (η⁵ -tetrahydrofluorenyl)Rh(cod) (1 b) with I₂ is complicated by the side formation of [(cod)RhI]₂ . The reaction of 2 b with 2,2'-bipyridyl leads to cation [(η⁵ -tetrahydrofluorenyl)Rh(2,2'-bipyridyl)I]⁺ (3). The halide abstraction from 2 a,b with thallium or silver salts allowed us to prepare sandwich compounds with incoming cyclopentadienyl, dicarbollide and mesityleneligands [(η⁵ -tetrahydrofluorenyl)RhCp]⁺ (4), (η⁵ -tetrahydrofluorenyl)Rh(η-7,8-C₂ B₉ H₁₁ ) (5), and [(η⁵ -tetrahydrofluorenyl)Rh(η-mesitylene)]²⁺ (6). The structures of 1 b, 2 b ⋅ 2I₂ , 3PF₆ , 4TlI₄ , 5, and [(cod)RhI]₂ were determined by X-ray diffraction. Compounds 2 a,b efficiently catalyze the oxidative coupling of benzoic acids with alkynes to selectively give isocoumarins or naphthalenes, depending on the reaction temperature. Moreover, they showed moderate catalytic activity in other annulations of alkynes with aromatic compounds (such as benzamide, acetanilide, etc.) which proceed through CH activation. Compound 2 b also effectively catalyzes the reductive amination of aldehydes and ketones in the presence of carbon monoxide and water via water-gas shift reaction, giving amines in high yields (67-99 %).

Polyether complexes of groups 13 and 14

Notable aspects of the chemistry of polyether complexes of group 13 and 14 elements are reviewed.

Bis(adamantan-1-aminium) tetrachloridozincate(II) 18-crown-6 monohydrate clathrate

The structure of the title compound [systematic name: bis(adamantan-1-aminium) tetrachloridozincate(II)-1,4,7,10,13,16-hexaoxacyclooctadecane-water (1/1/1)], (C(10)H(18)N)(2)[ZnCl(4)] x C(12)H(24)O(6) x H(2)O, consists of supramolecular rotator-stator assemblies and ribbons of hydrogen bonds parallel to [010]. The assemblies are composed of one protonated adamantan-1-aminium cation and one crown ether molecule (1,4,7,10,13,16-hexaoxacyclooctadecane) to give an overall [(C(10)H(18)N)(18-crown-6)](+) cation. The -NH(3)(+) group of the cation nests in the crown and links to the crown-ether O atoms through N-H...O hydrogen bonds. The 18-crown-6 ring adopts a pseudo-C(3v) conformation. The second adamantan-1-aminium forms part of ribbons of adamantan-1-aminium-water-tetrachloridozincate units which are interconnected by O-H...Cl, N-H...O and N-H...Cl hydrogen bonds via three different continuous rings with R(5)(4)(12), R(4)(3)(10) and R(3)(3)(8) motifs.

Metal–organic frameworks incorporating Cu3(μ3-OH) clusters

Interaction of 4,4-bi(1,2,4-triazole) (btr) with copper(II) chloride (bromide) in aqueous or aqueous alcohol media led to a series of coordination polymers featuring the formation of mu 3-hydroxotricopper(II) clusters and their integration into 3D frameworks. These unprecedented structures originate in the propagation of trigonal hydroxotricopper(II) clusters bridged by tri- or tetradentate organic ligands. Complex [{Cu3(mu3-OH)}{Cu3(mu3-O)}(mu4-btr)3(H2O)4(OH)2Cl6]Cl.0.5H2O adopts a structure of SrSi2 topology, with eight-fold interpenetration of the coordination frameworks. The structure of [{Cu3(mu3-OH)}2(mu3-btr)6(mu4-btr)(mu-X)X4]X5.nH2O (X = Br, n = 6; X = Cl, n = 8) involves 2D coordination layers [{Cu3(mu3-OH)}(mu3-btr)3]n with an exceptional (3,6)-net topology, which are cross-linked by tetradentate btr ligands and bridging chloride (bromide) ions.