Synthesis, Structure, and Magnetic Behavior of Bis(2-amino-5-fluoropyridinium) Tetrachlorocuprate(II)

Abstract

Reaction of CuCl2 with 2-amino-5-fluoropyridine and HCl in aqueous solution yields bis(2-amino-5-fluoropyridinium) tetrachlorocuprate(II), (5FAP)2CuCl4, (1). The complex crystallizes in the monoclinic space group P21/c with cell dimensions a = 6.926(7) A, b = 21.73(2) A, c = 10.911(10) A, beta = 100.19(2) degrees , V = 1616(3) A3, and R1 = 0.0424 based on 2640 independent reflections. The crystal packing shows that each tetrachlorocuprate ion has four nearest-neighbor Cu(II) ions through three types of Cu-Cl...Cl-Cu potential magnetic interactions: one short Cl...Cl distance (d1 = 3.657 A) and two longer Cl...Cl distances (d2 = 4.073 A) that form a layered distorted honeycomb structure. The third nearest neighbor (d3 = 4.239 A) links these layers into a three-dimensional structure. Both powder and single-crystal magnetic susceptibility measurements on 1, over the temperature range of 1.8-325 K, show significant antiferromagnetic interactions. Attempts to analyze the data using a variety of models showed a best fit to the strong-rung ladder model, with 2Jrung = -17.170(14) and 2Jrail = -5.94(5) K [-11.92(1) and -4.13(3) cm(-1), respectively] for the powder, although a comparable result is obtained using an alternate chain model. However, neither of these two models is compatible with a layered distorted honeycomb crystal packing structure. A first-principles bottom-up theoretical study using the 165 K crystallographic data reproduces the macroscopic properties and reveals that at low temperature the crystal has a 3D magnetic topology (all three magnetic pathways are significant) and a singlet ground state.

Copper(II) complexes of 2-amino-5-chloro-3-fluoropyridine: syntheses and magnetic properties of (3,5-FCAP)2CuX2 and (3,5-FCAPH)2CuX4

“…Fluorine is an excellent hydrogen bond acceptor and can change the packing structure and therefore magnetism of a Cu(II) complex. However, only three copper pyridine complexes using fluorine as a substituent have been synthesized and studied for magnetism and structural correlations: (2-amino-5-trifluoromethylpyridinium) 2 [CuX 4 ] [20] (X = Cl or Br) and (2-amino-5-fluoropyridinium) 2 [CuCl 4 ] [21]. This family must be expanded to determine the utility of fluorine as a substituent for directing crystal packing and, as a result, magnetic interactions.…”

Synthesis, structure and magnetic properties of copper(II) complexes of 2-amino-5-trifluoromethylpyridine (5-TFMAP): (5-TFMAP)2CuX2 (X=Cl or Br), (5-TFMAP)3CuBr2 and [(5-TFMAP)2CuBr2](5-TFMAPH)Br

“…Data on this family is known for 2-amino-5-methylpyridinium and 2-amino-5-chloropyridinium CuX 4 À2 salts (X = Cl, Br) and for the 2-amino-5-bromopyridinium tetrabromocuprate salt where two-dimensional magnetic layers were formed [9]. Related compounds where S@H [10], CN [11], NO 2 [12], F [13], and I [14] have also been reported which generate a wide variety of lattice types.…”

Syntheses, crystal structures, weak interaction, magnetic and photoluminescent properties of two new organic–inorganic molecular solids with disubstituted benzyl triphenylphosphinium and tetra(isothiocyanate)cobalt(II) anion

“…In the recent past, the rational design and synthesis of molecular solids based on inorganic complex anions and organic cations have attracted much attention not only due to particular physical properties such as magnetism, ferroelectricity, nonlinear optical activity and conductivity but also for their capability of exploring the new fields of condensed physics and materials science [1][2][3][4][5][6]. The structural topology of the molecular solids can be tuned by judicious selection of the anions and the counter organic cation, and some weak interactions such as directional hydrogen bonds, XÁ Á ÁX (X = S, Cl, Br, etc.…”

“…), pÁ Á Áp or pÁ Á Áp interactions, etc. may also often play an important role in the construction of these molecular materials [3,[6][7][8][9][10]. The transition metal coordination chemistry of thiocyanate or isothiocyanate ligands has extensively been developed for several decades mostly in view of the significance of the corresponding complexes in new fields like crystal engineering, supramolecular chemistry and host-gust chemistry [1,[11][12][13][14][15][16].…”