Coinage Metal Pyrazolates [(3,5-(CF₃)₂Pz)M]₃ (M = Au, Ag, Cu) as Buckycatchers

The synthesis and characterization of supramolecular assemblies {C₆₀<b>[M₃]₄</b>}_∞ consisting of C₆₀ and coinage metal pyrazolates <b>[M₃]</b> (i.e., [(3,5-(CF₃)₂Pz)­M]₃, where Pz = pyrazolate and M = Au, Ag, and Cu) are reported. {C₆₀<b>[Cu₃]₄</b>}_∞, {C₆₀<b>[Ag₃]₄</b>}_∞ and {C₆₀<b>[Au₃]₄</b>}_∞ form isomorphous crystals. The <b>[M₃]</b> moieties adopt a concave conformation to complement the convex C₆₀ surface. They exist as dimers of trimers (i.e., hexanuclear <b>[M₃]₂</b> units) that are held together by three close M···M metallophilic interactions at 3.1580(17), 3.2046(7), and 3.2631(7) Å for copper, silver, and gold systems, respectively. The <b>[M₃]₂</b> moieties surround each C₆₀ in a tetrahedral fashion, while each <b>[M₃]₂</b> is sandwiched by two C₆₀ molecules to form a supramolecular 3D assembly

Synthesis and Structure of [Fe(TPA)Cl2](ClO4) and [{Fe(TPA)Cl}2O](ClO4)2 Where TPA = Tris-(2-pyridylmethyl)amine

Abstract: [Fe(TPA)Cl2](ClO4), where TPA is tris-(2-pyridylmethyl)amine, crystallizes in the orthorhombic space group P212121 with Z = 4, a = 8.6264(10) Å, b = 15.459(3) Å, and c = 16.008(3) Å. The structure was determined at 110 K from 4333 reflections (3520 observed) with R = 0.041 (Rw = 0.082). The iron is pseudo-octahedral with the two chloride ions cis. The Fe-Cl bond trans to the tertiary amine is shorter. [{Fe(TPA)Cl}2O](ClO4)2 exhibits two polymorphic monoclinic forms, and the monohydrate also crystallizes in a monoclinic form. For the P21/c polymorph, Z = 2, a = 10.839(2) Å, b = 15.956(3) Å, c = 12.416(2) Å, β = 107.024(10)°, and the structure was determined at 95 K from 6514 reflections (3974 observed) with R = 0.052 (Rw = 0.099). For the C2/c polymorph, Z = 4, a = 20.5023(17) Å, b = 15.2711(13) Å, c = 16.1069(11) Å, β = 124.465(4)°, and the structure was determined at 161 K from 6250 reflections (3130 observed) with R = 0.0632 (Rw = 0.1229). For the hydrate, P21/n, Z = 4, a = 16.201(2) Å, b = 16.980(3), c = 16.451(3), β = 112.234(5)°, and the structure was determined at 100 K from 12,745 reflections (6600 observed) with R = 0.097 (Rw = 0.190). In each of the [{Fe(TPA)Cl}2O]2+ units, each iron is pseudo-octahedral with the chloride and oxide ions cis. The oxide bridge is linear, and the two chlorides are anti. The Fe-N distance for the pyridyl ring trans to the oxide bridge is quite long due to the trans influence of the oxide. Graphic Abstract: The X-ray structures of [Fe(TPA)Cl2](ClO4), where TPA is tris-(2-pyridylmethyl)amine, and three polymorphs of dimeric [{Fe(TPA)Cl}2O](ClO4)2 are presented and discussed. [Figure not available: see fulltext.

Zinc-Mediated Carbene Insertion to C–Cl Bonds of Chloromethanes and Isolable Zinc(II) Isocyanide Adducts

The zinc adduct {[HB­(3,5-(CF₃)₂Pz)₃]­Zn}⁺, which was generated from [HB­(3,5-(CF₃)₂Pz)₃]­ZnEt and [Ph₃C]­{B­[3,5-(CF₃)₂C₆H₃]₄}, catalyzes the activation of C–halogen bonds of chloromethanes via carbene insertion. Ethyl diazoacetate serves as the carbene precursor. The presence of {[HB­(3,5-(CF₃)₂Pz)₃]­Zn}⁺ in the reaction mixture was confirmed by obtaining {[HB­(3,5-(CF₃)₂Pz)₃]­Zn­(CN^tBu)₃}⁺ using CN^tBu as a trapping agent. {[HB­(3,5-(CF₃)₂Pz)₃]­Zn­(CN^tBu)₃}⁺ loses one zinc-bound CN^tBu easily to produce five-coordinate {[HB­(3,5-(CF₃)₂Pz)₃]­Zn­(CN^tBu)₂}⁺

Syntheses and Structures of [Fe(TPA)X2](ClO4) and [{Fe(TPA)Y}2O](ClO4)2 Where TPA = Tris-(2-pyridylmethyl)amine, X = N3, or Br, and Y = N3, Br, NCO, or NCS

[Fe(TPA)(N3)2](ClO4) and [Fe(TPA)Br2](ClO4), where TPA is tris-(2-pyridylmethyl)amine, crystallize in the monoclinic space group P21/c with a = 8.7029(5) Å, b = 19.168(1) Å, c = 13.5728(7) Å, β = 101.472(3)°, and a = 8.944(3) Å, b = 16.578(6) Å, c = 15.108(6) Å, β = 103.18(2)°, respectively. The structures were determined at 150 K from 3397 reflections (1426 observed) with R = 0.063 (Rw = 0.097), and at 115 K from 5617 reflections (2261 observed) with R = 0.057 (Rw = 0.065), respectively. In both cases, the iron is pseudo-octahedral with the two halide/pseudohalide ions cis. The Fe–X bond trans to the tertiary amine is shorter. The structures of [{Fe(TPA)X}2O](ClO4)2 where X = N3, Br, NCO, and two polymorphic forms of NCS, are also reported. The azide derivative [CH3CN solvate, monoclinic P21/n, a = 11.8038(11) Å, b = 22.547(2) Å, c = 17.344(2) Å, β = 106.972(4)°, determined at 100 K from 8972 reflections (4404 observed) with R = 0.087 (Rw = 0.145)] has two distinct Fe environments—the tertiary amine is cis to the oxido bridge at one site and is trans to the oxido bridge at the other site; the trans Fe–N3° distance is longer. Both the Br and NCO derivatives are monoclinic, C2/c [with a = 16.1480(17), b = 17.2036(13), c = 16.8521(12), β = 111.204(10), data collected at 293 K, 3753 reflections (2404 observed), R = 0.069 (Rw = 0.151), and a = 15.7470(9), b = 18.2270(11), c = 16.8950(8), β = 110.666(3), data collected at 90 K, 5392 reflections (3028 observed), R = 0.064 (Rw = 0.091), respectively]. Both polymorphs of the NCS derivative are monoclinic—one is P21/c and the other P21/n [a = 11.075(2), b = 15.436(2), c = 12.351(2), β = 95.528(7), data collected at 90 K, 5378 reflections (4345 observed), R = 0.068 (Rw = 0.198), and a = 12.396(2), b = 15.428(3), c = 44.505(8), β = 95.211(7), data collected at 110 K, 16,527 reflections (6540 observed), R = 0.069 (Rw = 0.105), respectively]. For the Br, NCO and NCS dimers, each iron of the [{Fe(TPA)X}2O]2+ unit is pseudo-octahedral with the halide/pseudohalide and oxide ions cis. The oxide bridge is linear, and the two halides/pseudohalides are anti. The ranking of trans influence of the ligands is O2− ≫ Br− \u3e Cl− \u3e N3− \u3e NCO− ≥ NCS− \u3e pyridyl \u3e tertiary amine and the ranking of cis influence of the ligands is O2− ≫ N3− \u3e NCO− \u3e Cl− ≥ Br− \u3e NCS−. Graphical Abstract: The X-ray structures of two monomeric [Fe(TPA)(X)2](ClO4), where TPA is tris-(2-pyridylmethyl)amine and X = N3, and Br, and four dimeric [{Fe(TPA)Y}2O](ClO4)2, where Y =N3, Br, NCO, and NCS are presented and discussed. [Figure not available: see fulltext.

Silver(I) and Copper(I) Adducts of a Tris(pyrazolyl)borate Decorated with Nine Trifluoromethyl Groups

Silver and copper ethylene adducts and the silver carbonyl complex of the tris­(pyrazolyl)­borate [HB­(3,4,5-(CF₃)₃Pz)₃]⁻ (which is based on one of the most acidic pyrazoles known) have been synthesized. ¹³C NMR resonance signals of metal-bound ethylene carbon atoms of [HB­(3,4,5-(CF₃)₃Pz)₃]­Ag­(C₂H₄) and [HB­(3,4,5-(CF₃)₃Pz)₃]­Cu­(C₂H₄) appear at δ 111.6 and 94.9, respectively. The CO stretching frequency of the silver adduct [HB­(3,4,5-(CF₃)₃Pz)₃]­Ag­(CO) is significantly higher than that of free CO, but it appears at a region less sensitive to the ligand electronic effects of tris­(azolyl)­borate silver adducts

Zinc(II)-Mediated Carbene Insertion into C–H Bonds in Alkanes

The cationic zinc adduct {[HB­(3,5-(CF₃)₂Pz)₃]­Zn­(NCMe)₂}­ClO₄ catalyzes the functionalization of tertiary, secondary, and primary C–H bonds of alkanes via carbene insertion. Ethyl diazoacetate serves as the :CHCO₂Et carbene precursor. The counteranion, supporting ligand, and coordinating solvents affect the catalytic activity. An in situ generated {[HB­(3,5-(CF₃)₂Pz)₃]­Zn}⁺ species containing a bulkier {B­[3,5-(CF₃)₂C₆H₃]₄}⁻ anion gives the best results among the zinc catalysts used