As you like it: Ag(η2‐As4)2+pftb− can be used to store yellow arsenic (As4). From it, As4 can be easily released to give concentrated, light‐stable solutions. These As4 solutions, and those of white ...phosphorus (P4), allowed molecular As4 and P4 to be encapsulated inside giant, spherical aggregates and polymeric matrices, enabling the first determination of their EE (E=P, As) bond lengths by diffraction methods.
Slow diffusion reactions of the pentaphosphaferrocene Cp*Fe(η5‐P5) (Cp*=η5‐C5Me5 (1)) with CuX (X=Cl, Br, I) in different stoichiometric ratios and solvent mixtures result in the formation of one‐ ...and two‐dimensional polymeric compounds 2–6 with molecular formula {Cu(μ‐X)}{Cp*Fe(μ3,η5:η1:η1‐P5)}n (X=Cl (2 a), I (2′c)), {Cu(μ‐I)}{Cp*Fe(μ3,η5:η1:η1‐P5)}n (3), {CuX}{Cp*Fe(μ4,η5:η1:η1:η1‐P5)}n (X=Cl (4 a), Br (4 b), I (4 c), Br (4′b), I (4′c)), {Cu3(μ‐I)2(μ3‐I)}{Cp*Fe(μ5,η5:η1:η1:η1:η1‐P5)}n (5) and {Cu4(μ‐X)4(CH3CN)}{Cp*Fe(μ7,η5:η2:η1:η1:η1:η1:η1‐P5)}n (X=Cl (6 a), Br (6 b)), respectively. The polymeric compounds have been characterised by single‐crystal X‐ray diffraction analyses and, for selected examples, by magic angle spinning (MAS) NMR spectroscopy. The solid‐state structures demonstrate the versatile coordination modes of the cyclo‐P5 ligand of 1, extending from two to five coordinating phosphorus atoms in either σ or σ‐and‐π fashion. In compounds 2 a, 2′c and 3, two phosphorus atoms of 1 coordinate to copper atoms in a 1,2 coordination mode (2 a, 2′c) and an unprecedented 1,3 coordination mode (3) to form one‐dimensional polymers. Compounds 4 a–c, 4′b, 4′c and 5 represent two‐dimensional coordination polymers. In compounds 4, three phosphorus atoms coordinate to copper atoms in a 1,2,4 coordination mode, whereas in 5 the cyclo‐P5 ligand binds in an unprecedented 1,2,3,4 coordination mode. The crystal structures of 6 a,b display a tilted tube, in which all P atoms of the cyclo‐P5 ligand are coordinated to copper atoms in σ‐ and π‐bonding modes.
The right tool for the job: Small changes in the reaction conditions of pentaphosphaferrocene with Cu halides have a decisive impact on the supramolecular self‐assembly process to form 1D and 2D polymers. The novel products have been systematically investigated using single‐crystal X‐ray structure analyses and high‐resolution 31P solid‐state NMR techniques including R‐TOBSY experiments (see figure).
The pnictogen-centered nucleophiles LiE(SiMe3)2 (E = N, P, or As) substitute a cyclopentadienide ligand of chromocene (Cp2Cr), with elimination of lithium cyclopentadienide, to give the series of ...pnictogen-bridged compounds (μ:η2:η5-Cp)Cr{μ-N(SiMe3)2}2Li (1) and (η5-Cp)Cr{μ-E(SiMe3)2}2, with E = P (2) or E = As (3). Whereas 1 is a heterobimetallic coordination polymer, 2 and 3 are homometallic dimers, with the differences being due to a structure-directing influence of the hard or soft character of the bridging group 15 atoms. For compound 1, the experimental magnetic susceptibility data were accurately reproduced by a single-ion model based on high-spin chromium(II) (S = 2), which gave a g-value of 1.93 and an axial zero-field splitting parameter of D = −1.83 cm–1. Determinations of phosphorus- and arsenic-mediated magnetic exchange coupling constants, J, are rare: in the dimers 2 and 3, variable-temperature magnetic susceptibility measurements identified strong antiferromagnetic exchange between the chromium(II) centers, which was modeled using the spin Hamiltonian H = −2J(S CrA·S CrB), and produced large coupling constants of J = −166 cm–1 for 2 and −77.5 cm–1 for 3.
As you like it: Ag( eta super(2)-As sub(4) ) sub(2) super(+)pftb super(-) can be used to store yellow arsenic (As sub(4)). From it, As sub(4) can be easily released to give concentrated, light-stable ...solutions. These As sub(4) solutions, and those of white phosphorus (P sub(4)), allowed molecular As sub(4) and P sub(4) to be encapsulated inside giant, spherical aggregates and polymeric matrices, enabling the first determination of their E--E (E=P, As) bond lengths by diffraction methods.
Slow diffusion reactions of the pentaphosphaferrocene Cp*Fe(η5-P5) (Cp*=η5-C5Me5 (1)) with CuX (X=Cl, Br, I) in different stoichiometric ratios and solvent mixtures result in the formation of one- ...and two-dimensional polymeric compounds 2-6 with molecular formula {Cu(µ-X)}{Cp*Fe(µ3,η5:η1:η1-P5)}n (X=Cl (2a), I (2'c)), {Cu(µ-I)}{Cp*Fe(µ3,η5:η1:η1-P5)}n (3), {CuX}{Cp*Fe(µ4,η5:η1:η1:η1-P5)}n (X=Cl (4a), Br (4b), I (4c), Br (4'b), I (4'c)), {Cu3(µ-I)2(µ3-I)}{Cp*Fe(µ5,η5:η1:η1:η1:η1-P5)}n (5) and {Cu4(µ-X)4(CH3CN)}{Cp*Fe(µ7,η5:η2:η1:η1:η1:η1:η1-P5)}n (X=Cl (6a), Br (6b)), respectively. The polymeric compounds have been characterised by single-crystal X-ray diffraction analyses and, for selected examples, by magic angle spinning (MAS) NMR spectroscopy. The solid-state structures demonstrate the versatile coordination modes of the cyclo-P5 ligand of 1, extending from two to five coordinating phosphorus atoms in either σ or σ-and-π fashion. In compounds 2a, 2'c and 3, two phosphorus atoms of 1 coordinate to copper atoms in a 1,2 coordination mode (2a, 2'c) and an unprecedented 1,3 coordination mode (3) to form one-dimensional polymers. Compounds 4a-c, 4'b, 4'c and 5 represent two-dimensional coordination polymers. In compounds 4, three phosphorus atoms coordinate to copper atoms in a 1,2,4 coordination mode, whereas in 5 the cyclo-P5 ligand binds in an unprecedented 1,2,3,4 coordination mode. The crystal structures of 6a,b display a tilted tube, in which all P atoms of the cyclo-P5 ligand are coordinated to copper atoms in σ- and π-bonding modes.
PDF
