0000000000139809
AUTHOR
Theocharis C. Stamatatos
New structural motifs in Mn cluster chemistry from the ketone/gem-diol and bis(gem-diol) forms of 2,6-di-(2-pyridylcarbonyl)pyridine: {MnII4MnIII2} and {MnII4MnIII6} complexes
The employment of the tripyridyl/diketone ligand 2,6-di-(2-pyridylcarbonyl)pyridine [(py)CO(py)CO(py)], in conjunction with azides (N3−), in Mn cluster chemistry has afforded the mixed-valence (II/III) complexes [MnII4MnIII2(N3)6Cl4(L1)2(DMF)4] (1) and [MnII4MnIII6O2(N3)12(L1)2(L2H)2(DMF)6] (2) in good yields. The resulting ligands L12− and L2H3− are the dianion and trianion of the ketone/gem-diol (L1H2) and bis(gem-diol) (L2H4) forms of (py)CO(py)CO(py), respectively, as derived from the metal-assisted hydrolysis of the parent dicarbonyl organic compound. Under the same synthetic conditions (i.e., reaction solvents, temperature and stirring time), the chemical identity of the two complexes…
Experimental determination of single molecule toroic behaviour in a Dy8 single molecule magnet
The enhancement of toroic motifs through coupling toroidal moments within molecular nanomagnets is a new, interesting and relevant approach for both fundamental research and potential quantum computation applications. We investigate a Dy8 molecular cluster and discover it has a antiferrotoroic ground state with slow magnetic relaxation. The experimental characterization of the magnetic anisotropy axes of each magnetic center and their exchange interactions represents a considerable challenge due to the non-magnetic nature of the toroidal motif. To overcome this and obtain access to the low energy states of Dy8 we establish a multi-orientation single-crystal micro Hall sensor magnetometry ap…
The first member of a second generation family of ligands derived from metal-ion assisted reactivity of di-2,6-(2-pyridylcarbonyl)pyridine: Synthesis and characterization of a MnII/III4 rhombus
Abstract Nucleophilic attack by the carbanion −CH2COCH3 at the carbonyl carbon atoms of 2,6-di-(2-pyridylcarbonyl)pyridine, pyCOpyCOpy, in the presence of Mnn+ ions under basic conditions has yielded the cationic cluster [Mn4(OH)2(L)2(H2O)2](ClO4)4 (1), where L2− is the (py)C(CH2COCH3)(O−)(py)C(CH2COCH3)(O−)(py) dianion. The cluster cation possesses a planar {MnII2MnIII2(μ3-OH)2(μ-OR)4}4+ rhombus core, resulting from two μ3-OH− ions and two η1:η2:η1:η1:η1:η2:η1:μ3 bridging L2− groups from the in situ formed ligand. Complex 1 is antiferromagnetically coupled with an unusual S = 2 ground state resulting from spin frustration effects within the triangular Mn3 subunits of the cluster.
Increasing the nuclearity and spin ground state in a new family of ferromagnetically-coupled {Ni10} disk-like complexes bearing exclusively end-on bridging azido ligands
The synthesis of a new family of ferromagnetically-coupled {Ni10} clusters counterbalanced by various [Ln(NO3)5]2− ions is herein described. The resulting compounds are organic chelate-free and the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology reminiscent of the structure of the brucite mineral.
Further synthetic investigation of the general lanthanoid(iii) [Ln(iii)]/copper(ii)/pyridine-2,6-dimethanol/carboxylate reaction system: {CuII5LnIII4} coordination clusters (Ln = Dy, Tb, Ho) and their yttrium(iii) analogue
In addition to previously studied {CuII3Gd6}, {CuII8Gd4}, {CuII15Ln7} and {CuII4Ln8} coordination clusters (Ln = trivalent lanthanide) containing pdm2− or Hpdm− ligands (H2pdm = pyridine-2,6-dimethanol) and ancillary carboxylate groups (RCO2−), the present work reports the synthesis and study of three new members of a fifth family of such complexes. Compounds [Cu5Ln4O2(OMe)4(NO3)4(O2CCH2But)2(pdm)4(MeOH)2] (Ln = Dy, 1; Ln = Tb, 2; Ln = Ho, 3) were prepared from the reaction of Ln(NO3)3·xH2O (x = 5, 6), CuX2·yH2O (X = ClO4, Cl, NO3; y = 6, 2 and 3, respectively), H2pdm, ButCH2CO2H and Et3N (2 : 2.5 : 2 : 1 : 9) in MeCN/MeOH. Rather surprisingly, the copper(II)/yttrium(III) analogue has a sli…
Organic chelate-free and azido-rich metal clusters and coordination polymers from the use of Me3SiN3: a new synthetic route to complexes with beautiful structures and diverse magnetic properties
In this Feature Article, we highlight the feasibility of a new, recently developed approach towards the synthesis of high-spin molecules and single-molecule magnets (SMMs). The key to the preparation of such molecular compounds is the organic azide precursor Me3SiN3, which fosters the formation of 3d-metal azido clusters and coordination polymers without requiring the assistance of any organic chelating/bridging group. All the isolated compounds contain metallic cores which are surrounded by end-on bridging N3− groups. Consequently, the reported molecular materials exhibit ferromagnetic exchange interactions between the spin carriers, resulting in the stabilization of the maximum possible s…
Slow Magnetization Relaxation in a 1-D Double-Chain Coordination Polymer Composed of {Dy<sup>III</sup> <sub>4</sub>} Repeating Units
The "unsuccessful" synthesis of the non-commercially available 'Dy(O2CPh)3' precursor from the stoichiomet- ric reaction of Dy(NO3)3·5H2O with 3 equivalents of NaO2CPh in MeCN/H2O has led instead to the "successful" isolation and structural characterization of the 1-D coordination polymer (Dy4(O2CPh)12(H2O)8)n·2n(PhCO2H)·n(MeCN) (1·2n(PhCO2H)·n(MeCN)) in excellent yields (~90%). The one-dimensional double-chain structure of 1 was resulted from the linkage of two parallel chains by syn,anti-� 1 :� 1 :μ PhCO2 - groups. The lattice structure of 1 is further extended to a 2-D network through hydrogen bonding and - stacking interactions. The observation of out-of-phase (� �� M) ac susceptibility…
CCDC 1864765: Experimental Crystal Structure Determination
Related Article: Jasmin Krause, Dimitris I. Alexandropoulos, Luca M. Carrella, Eva Rentschler, Theocharis C. Stamatatos|2018|Chem.Commun.|54|12499|doi:10.1039/C8CC07722C
CCDC 2038607: Experimental Crystal Structure Determination
Related Article: Despina Dermitzaki, Catherine P. Raptopoulou, Vassilis Psycharis, Albert Escuer, Spyros P. Perlepes, Julia Mayans, Theocharis C. Stamatatos|2021|Dalton Trans.|50|240|doi:10.1039/D0DT03582C
CCDC 1869182: Experimental Crystal Structure Determination
Related Article: Jasmin Krause, Dimitris I. Alexandropoulos, Luca M. Carrella, Eva Rentschler, Theocharis C. Stamatatos|2018|Chem.Commun.|54|12499|doi:10.1039/C8CC07722C
CCDC 1503292: Experimental Crystal Structure Determination
Related Article: Dimosthenis P. Giannopoulos, Luís Cunha-Silva, Rafael Ballesteros-Garrido, Rafael Ballesteros, Belén Abarca, Albert Escuer, Theocharis C. Stamatatos|2016|RSC Advances|6|105969|doi:10.1039/C6RA22953K
CCDC 1864766: Experimental Crystal Structure Determination
Related Article: Jasmin Krause, Dimitris I. Alexandropoulos, Luca M. Carrella, Eva Rentschler, Theocharis C. Stamatatos|2018|Chem.Commun.|54|12499|doi:10.1039/C8CC07722C
CCDC 1864767: Experimental Crystal Structure Determination
Related Article: Jasmin Krause, Dimitris I. Alexandropoulos, Luca M. Carrella, Eva Rentschler, Theocharis C. Stamatatos|2018|Chem.Commun.|54|12499|doi:10.1039/C8CC07722C
CCDC 1503291: Experimental Crystal Structure Determination
Related Article: Dimosthenis P. Giannopoulos, Luís Cunha-Silva, Rafael Ballesteros-Garrido, Rafael Ballesteros, Belén Abarca, Albert Escuer, Theocharis C. Stamatatos|2016|RSC Advances|6|105969|doi:10.1039/C6RA22953K
CCDC 2038608: Experimental Crystal Structure Determination
Related Article: Despina Dermitzaki, Catherine P. Raptopoulou, Vassilis Psycharis, Albert Escuer, Spyros P. Perlepes, Julia Mayans, Theocharis C. Stamatatos|2021|Dalton Trans.|50|240|doi:10.1039/D0DT03582C