Iron(III), chromium(III) and cobalt(II) complexes with squarate: Synthesis, crystal structure and magnetic properties

Synthesis and Characterization of [M2(OH)2(C4O4)2(H2O)4]·2H2O (M = Al or Ga)

“…The M –O distances for 1 (1.876(3)–1.906(2) Å) and 2 (1.973(6) and 2.044(8) Å) compare well with values reported in the literature , , . The intramolecular M ··· M distances in compounds 1 and 2 are 2.924(2) and 3.018(2) Å, respectively, which are within the range of the M ··· M distances of the isostructural compounds [Fe 2 (OH) 2 (C 4 O 4 ) 2 (H 2 O) 4 ] · 2H 2 O (3.0722(6) Å) and [Cr 2 (OH) 2 (C 4 O 4 ) 2 (H 2 O) 4 ] · 2H 2 O (2.998 Å) …”

“…The hydrogen bonding network corresponds to the one described for the isostructural compound [Fe 2 (OH) 2 (C 4 O 4 ) 2 (H 2 O) 4 ] · 2H 2 O where D ··· A distances and the D –H ··· A angles of 2.661(4)–2.840(4) Å and 160.4(2)–176.4(2)° have been reported …”

“…Due to the comparably short distance between the donor oxygen atoms and the small size of the linker only few porous metal squarates are known, such as [Ca(C 4 O 4 )(H 2 O)], [Zr 6 O 4 (OH) 4 (C 4 O 4 ) 6 ], [Fe 3 (OH) 3 (C 4 O 4 )(C 4 O 4 ) 0.5 ], or [ M (H 2 O) 2 (C 4 O 4 )] ( M = Co 2+ , Mn 2+ , Zn 2+ ). Metal squarates containing trivalent metal ions have been exclusively reported as molecular complexes containing the metal ions Fe 3+ , Cr 3+ , and V 3+ , . In addition, transition metal squarates have also been intensively studied for their magneto‐structural properties since the C 4 O 4 2– ion is also known to mediate strong magnetic interactions among the central metal atoms …”

“…Metal squarates containing trivalent metal ions have been exclusively reported as molecular complexes containing the metal ions Fe 3+ , Cr 3+ , and V 3+ . [23,24] In addition, transition metal squarates have also been intensively studied for their magneto-structural properties since the C 4 O 4 2ion is also known to mediate strong magnetic interactions among the central metal atoms. [23][24][25][26][27] In this work, we present the synthesis and characterization of the aluminum and gallium squarate complexes, [Al 2 (OH) 2…”

Synthesis, structural characterization and computational studies of layered metal phosphonates: [M(HO3P–C5H4N–PO3H)2(H2O)2]n[MII= Co, Zn, Cd]

“…Tetragonally elongated Co II complexes are less common than the compressed, but it certainly can be concluded, that the a, D and l parameters are within the ranges of those reported for high-spin complexes. [33][34][35][36] The measured effective moment at 1.71 K (3.80m B ) is close to the calculated moment 3.68m B of the lowest Kramers doublet (S eff ¼ 1/2, g ¼ 4.25), which further validates the model with the virtually isolated metal ions.…”