Facile cyclization of sodium aminodiboranate to construct a boron-nitrogen-hydrogen ring.

A facile and efficient cyclization of sodium aminodiboranate to construct a boron-nitrogen-hydrogen ring is presented. This new strategy can be developed into a general method to prepare aminodiborane and its derivatives. Theoretical calculations show that a one-step cyclization mechanism is favored, where the dihydrogen bond plays an important role.

Phosphine Oxide Ligand Based Tetrahedral CoII Complexes with Field-induced Slow Magnetic Relaxation Behavior Modified by Terminal Ligands.

Two isostructural mononuclear CoII complexes, [Co(xantpo)(NCE)2 ] (E=S (1) and O (2); xantpo=9,9-dimethyl-4,5-bis(diphenylphosphoryl) xanthene), supported by a bidentate phosphine oxide ligand are reported. The cobalt complexes exhibit characteristic tetrahedral structures coordinated with two oxygen and two nitrogen atoms. Magnetic property measurements show their similar static magnetic behaviours but very different dynamic magnetic behaviours. Both complexes show field-induced slow magnetic relaxation behaviours, but the relaxation of 2 is much slower than that of 1. Fittings to the magnetic data and ab initio CASSCF calculations reveal significant changes in the zero field splitting (ZFS) parameters (D and E), which can be attributed to the small geometrical changes of the Co ions and the different ligand field strength of the two terminal ligands.

Pd supported on carbon containing nickel, nitrogen and sulfur for ethanol electrooxidation.

Carbon material containing nickel, nitrogen and sulfur (Ni-NSC) has been synthesized using metal-organic frameworks (MOFs) as precursor by annealing treatment with a size from 200 to 300 nm. Pd nanoparticles supported on the Ni-NSC (Pd/Ni-NSC) are used as electrocatalysts for ethanol oxidation in alkaline media. Due to the synergistic effect between Pd and Ni, S, N, free OH radicals can form on the surface of Ni, N and S atoms at lower potentials, which react with CH3CO intermediate species on the Pd surface to produce CH3COO- and release the active sites. On the other hand, the stronger binding force between Pd and co-doped N and S is responsible for enhancing dispersion and preventing agglomeration of the Pd nanoparticles. The Pd(20 wt%)/Ni-NSC shows better electrochemical performance of ethanol oxidation than the traditional commercial Pd(20 wt%)/C catalyst. Onset potential on the Pd(20 wt%)/Ni-NSC electrode is 36 mV more negative compared with that on the commercial Pd(20 wt%)/C electrode. The Pd(20 wt%)/Ni-NSC in this paper demonstrates to have excellent electrocatalytic properties and is considered as a promising catalyst in alkaline direct ethanol fuel cells.

Magnetic and luminescent properties of lanthanide coordination polymers with asymmetric biphenyl-3,2',5'-tricarboxylate.

Eight isostructural lanthanide coordination polymers [Ln(bptc)(phen)(H2O)]n (Ln = Dy for , Eu for , Tb for , Gd for , Sm for , Nd for , Yb for , Pr for ) were successfully prepared based on bridging asymmetric polycarboxylate ligand biphenyl-3,2',5'-tricarboxylic acid (H3bptc) and chelating 1,10-phenanthroline (phen) coligand. Single crystal X-ray analysis reveals that complexes have a (3,6)-connected CdI2-type coordination network consisting of paddle-wheel dimers [Ln2(CO2)4]. The magnetic and fluorescent properties of have been investigated. Significantly, the Dy(iii) complex behaves with slow relaxation of the magnetization, where the frequency-dependent out-of-phase signals are noticed.

High symmetry superoctahedron cluster [Mn(III)18O14]26+ from the use of N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine.

The use of flexible N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine has provided one new high symmetry superoctahedron with unprecedented aesthetically-pleasing Mn(III)18 clusters, which exhibits out-of-phase signals indicative of the slow magnetic relaxation.

High-spin tetranuclear Mn(II)(2)Mn(IV)(2) clusters with unique Mn(ii)-Mn(iv) magnetic exchange: synthesis, structures and magnetism.

Reactions of N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine (H(4)edte) with MnCl(2).4H(2)O or FeCl(3).6H(2)O in MeOH or MeCN with different bases yield four butterfly-like tetranuclear clusters with fused defective dicubane M(4)O(6) cores: [Mn(II)(2)Mn(IV)(2)(mu(4)-Hedte)(2)(thme)(2)].MeCN () (H(4)edte = N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine, H(3)thme = 1,1,1-tris(hydroxymethyl)ethane), [Mn(II)(2)Mn(IV)(2)(mu(4)-Hedte)(2)(thme)(2)].2MeOH (), [Fe(III)(4)(mu(4)-Hedte)(2)(N(3))(6)].2MeCN () and [Fe(III)(4)(mu(4)-edte)(2)(N(3))(4)(MeOH)(2)] (). Both and crystallize in the triclinic space group P1[combining macron], while and crystallize in the monoclinic space group P2(1)/c and P2(1)/n, respectively. The hexadentate Hedte(3-) ligand in , and the edte(4-) ligand in acts in a similar mu(4):eta(1):eta(1):eta(1):eta(2):eta(2):eta(3) coordination mode to bridge four metal ions into butterfly-like tetranuclear clusters with fused defective dicubane M(4)O(6) cores. Magnetic studies show that has the spin ground state S(T) = 8 while has the spin ground state S(T) = 0. Within the Mn(4)O(6) cluster core of , both Mn(iv)Mn(ii) and Mn(ii)Mn(ii) ferromagnetic interactions (J(Mn(iv)Mn(ii)) = +2.91 cm(-1) and J(Mn(ii)Mn(ii)) = +7.94 cm(-1)) occur contrary to the Fe(4)O(6) core, where antiferromagnetic exchange exists (J(aptical-Fe(iii)central-Fe(iii)) = -15.4 cm(-1) and J(central-Fe(iii)central-Fe(iii)) = -4.5 cm(-1)).

New Mn12 clusters with tunable oxidation states via the use of N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine.

Room-temperature reactions of N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine with manganese(II) salts yield a novel family of Mn(12) clusters incorporating the same Mn(12)O(4) core and tunable oxidation states of Mn(III)(x)Mn(II)(12-x) (x = 8, 10, and 12). Magnetic susceptibility data indicate that the spin of the ground state increases as the number of Mn(III) ions is increased, leading to increases in the magnitude of the out-of-phase ac susceptibility signal as the number of Mn(III) ions is increased.

Molecular tectonics: self-complementary supramolecular Se...N synthons directing assembly of 1D silver chains into 3D porous molecular architectures.

Reaction of 2,1,3-benzoselenadiazole (bsd) with AgNO3 results in the formation of a novel model example of a Se...N synthon directed molecular network of different polymorphs at different temperatures. Alpha-[Ag(bsd)2(NO3)] x 0.5bsd formed at ambient temperature, has a 3D porous molecular network constructed with monomeric [Ag(bsd)2(NO3)] motif, and has 1D channels that are encapsulated with 1D arrays of two-fold-disordered dimeric (bsd)2 guests aggregated by the self-complementary nonbonded Se...N interactions. This is the first molecular net directed by supramolecular Se...N synthons. The second polymorph, beta-[Ag(bsd)2(NO3)] x 0.5bsd, formed from an analogous reaction at 50 degrees C, contains a similar 3D molecular network constructed with tetrameric [Ag4(bsd)8(NO3)4] motif and 1D arrays of well-ordered dimeric (bsd)2 guests are encapsulated in the channels. Such ordered (bsd)2 dimers provide an excellent simplified dimeric model for MO calculations of intermolecular nonbonded Se...N interactions.