Semiconductive 2D arrays of pancake-bonded oligomers of partially charged TCNQ radicals

Multicentre two-electron (mc/2e or pancake bonding) bonding between 7, 7, 8, 8- tetracyanoquinodimethane (TCNQ) radical anions was studied on its 14 novel salts with planar organic cations. Formal charges of the TCNQδ− moieties are −1/2 and −2/3, and they form mc/2e bonded dimers, trimers and tetramers which are further stacked into extended arrays. Multicentre bonding within these oligomers is characterised by short interplanar separations of 2.9 − 3.2 Å ; distances between the oligomers are larger, typically > 3.3 Å. The stacks are laterally connected by C−H···N hydrogen bonding, forming 2D arrays. The nature of mc/2e bonding is characterised by structural, magnetic and electrical data. The compounds are found to be semiconductors, and high conductivity [10-2 Scm-1] correlates with short interplanar distances between pancake-bonded oligomers

Properties of homo- and heterometallic complexes prepared using tris(oxalato) and tris(chloranilato) building blocks

Istražene su reakcije građevnog bloka A3[ML3]·3H2O {A = K+, NH4+ ili [(C4H9)4N)4]+; M = Cr3+ ili Fe3+; L = C2O42– ili C6O4Cl22–}, bakrove(II) soli i N-donorskog liganda (imidazola, 2,2'-bipiridina, 1,10-fenantrolina ili 2,2':6',2''-terpiridina), uz dodatak tetraklorkinona i KI u nekim reakcijama, tehnikom nadslojavanja ili u hidrotermalnim uvjetima. Priređen je 51 novi spoj: 35 oksalatnih, od čega je 29 heterometalnih (19 [CuIICrIII] i 10 [CuIIFeII/III]), i 12 kloranilatnih, od čega je 7 heterometalnih (4 [CuIICrIII] i 3 [CuIIFeIII]). Pripravljeno je 9 kompleksa s mononuklearnim, 11 s dinuklearnim, 5 s trinuklearnim, 2 s tetranuklearnim i 1 s heksanuklearnim jedinkama. Priređeno je i 13 jednodimenzijskih te 6 trodimenzijskih koordinacijskih polimera. Svi su spojevi okarakterizirani IR spektroskopijom, te su im određene molekulske i kristalne strukture. Za 15 spojeva su njihova svojstva ispitana metodama termičke analize te magnetska svojstva za 14 spojeva koji sadrže premošćujuću oksalatnu skupinu, odnosno električna svojstva za 7 spojeva. 5 heterometalnih oksalatnih kompleksa je proučavano u obliku molekulskih prekursora za dobivanje mješovitih metalnih oksida termičkom razgradnjom; dobivenom jednofaznom sustavu CuCrO2 istražena je fotokatalitička aktivnost u reakciji cijepanja vode. Kod 2 spoja je uočen fotokromizam, odnosno termokromizam kod 1.The reactions of building block A3[ML3]·3H2O {A = K+, NH4+ or [(C4H9)4N)4]+; M = Cr3+ or Fe3+; L = C2O42– or C6O4Cl22–}, copper(II) salt and N-donor ligand (imidazole, 2,2'-bipyridine, 1,10-phenanthroline or 2,2':6',2"-terpyridine), with the addition of tetrachloroquinone and KI in some reactions were studied, in layering technique or in hydrothermal conditions. 51 new compounds were prepared: 35 oxalate-based {29 heterometallic [19 (CuIICrIII) and 10 (CuIIFeII/III)]}, and 12 chloranilate {7 heterometallic [4 (CuIICrIII) and 3 [CuIIFeIII]} were isolated. In these reactions 9 complexes with mononuclear, 11 with dinuclear, 5 with trinuclear, 2 with tetranuclear and 1 with hexanuclear units were obtained. 13 one-dimensional and 6 three-dimensional coordination polymers were formed. IR and structural characterization was done for all the complexes. For 15 compounds thermal properties were investigated, for 14 compounds with bridging oxalate group magnetic properties, and for 7 compounds electric properties were studied. 5 selected heterometallic oxalate complexes were tested as molecular precursors for mixed-metal oxides and single-phased CuCrO2 was obtained. Its photocatalytic activity in water splitting reaction was tested. 2 compounds showed photochromism and 1 thermochromism

Properties of homo- and heterometallic complexes prepared using tris(oxalato) and tris(chloranilato) building blocks

Istražene su reakcije građevnog bloka A3[ML3]·3H2O {A = K+, NH4+ ili [(C4H9)4N)4]+; M = Cr3+ ili Fe3+; L = C2O42– ili C6O4Cl22–}, bakrove(II) soli i N-donorskog liganda (imidazola, 2,2'-bipiridina, 1,10-fenantrolina ili 2,2':6',2''-terpiridina), uz dodatak tetraklorkinona i KI u nekim reakcijama, tehnikom nadslojavanja ili u hidrotermalnim uvjetima. Priređen je 51 novi spoj: 35 oksalatnih, od čega je 29 heterometalnih (19 [CuIICrIII] i 10 [CuIIFeII/III]), i 12 kloranilatnih, od čega je 7 heterometalnih (4 [CuIICrIII] i 3 [CuIIFeIII]). Pripravljeno je 9 kompleksa s mononuklearnim, 11 s dinuklearnim, 5 s trinuklearnim, 2 s tetranuklearnim i 1 s heksanuklearnim jedinkama. Priređeno je i 13 jednodimenzijskih te 6 trodimenzijskih koordinacijskih polimera. Svi su spojevi okarakterizirani IR spektroskopijom, te su im određene molekulske i kristalne strukture. Za 15 spojeva su njihova svojstva ispitana metodama termičke analize te magnetska svojstva za 14 spojeva koji sadrže premošćujuću oksalatnu skupinu, odnosno električna svojstva za 7 spojeva. 5 heterometalnih oksalatnih kompleksa je proučavano u obliku molekulskih prekursora za dobivanje mješovitih metalnih oksida termičkom razgradnjom; dobivenom jednofaznom sustavu CuCrO2 istražena je fotokatalitička aktivnost u reakciji cijepanja vode. Kod 2 spoja je uočen fotokromizam, odnosno termokromizam kod 1.The reactions of building block A3[ML3]·3H2O {A = K+, NH4+ or [(C4H9)4N)4]+; M = Cr3+ or Fe3+; L = C2O42– or C6O4Cl22–}, copper(II) salt and N-donor ligand (imidazole, 2,2'-bipyridine, 1,10-phenanthroline or 2,2':6',2"-terpyridine), with the addition of tetrachloroquinone and KI in some reactions were studied, in layering technique or in hydrothermal conditions. 51 new compounds were prepared: 35 oxalate-based {29 heterometallic [19 (CuIICrIII) and 10 (CuIIFeII/III)]}, and 12 chloranilate {7 heterometallic [4 (CuIICrIII) and 3 [CuIIFeIII]} were isolated. In these reactions 9 complexes with mononuclear, 11 with dinuclear, 5 with trinuclear, 2 with tetranuclear and 1 with hexanuclear units were obtained. 13 one-dimensional and 6 three-dimensional coordination polymers were formed. IR and structural characterization was done for all the complexes. For 15 compounds thermal properties were investigated, for 14 compounds with bridging oxalate group magnetic properties, and for 7 compounds electric properties were studied. 5 selected heterometallic oxalate complexes were tested as molecular precursors for mixed-metal oxides and single-phased CuCrO2 was obtained. Its photocatalytic activity in water splitting reaction was tested. 2 compounds showed photochromism and 1 thermochromism

Properties of homo- and heterometallic complexes prepared using tris(oxalato) and tris(chloranilato) building blocks

Istražene su reakcije građevnog bloka A3[ML3]·3H2O {A = K+, NH4+ ili [(C4H9)4N)4]+; M = Cr3+ ili Fe3+; L = C2O42– ili C6O4Cl22–}, bakrove(II) soli i N-donorskog liganda (imidazola, 2,2'-bipiridina, 1,10-fenantrolina ili 2,2':6',2''-terpiridina), uz dodatak tetraklorkinona i KI u nekim reakcijama, tehnikom nadslojavanja ili u hidrotermalnim uvjetima. Priređen je 51 novi spoj: 35 oksalatnih, od čega je 29 heterometalnih (19 [CuIICrIII] i 10 [CuIIFeII/III]), i 12 kloranilatnih, od čega je 7 heterometalnih (4 [CuIICrIII] i 3 [CuIIFeIII]). Pripravljeno je 9 kompleksa s mononuklearnim, 11 s dinuklearnim, 5 s trinuklearnim, 2 s tetranuklearnim i 1 s heksanuklearnim jedinkama. Priređeno je i 13 jednodimenzijskih te 6 trodimenzijskih koordinacijskih polimera. Svi su spojevi okarakterizirani IR spektroskopijom, te su im određene molekulske i kristalne strukture. Za 15 spojeva su njihova svojstva ispitana metodama termičke analize te magnetska svojstva za 14 spojeva koji sadrže premošćujuću oksalatnu skupinu, odnosno električna svojstva za 7 spojeva. 5 heterometalnih oksalatnih kompleksa je proučavano u obliku molekulskih prekursora za dobivanje mješovitih metalnih oksida termičkom razgradnjom; dobivenom jednofaznom sustavu CuCrO2 istražena je fotokatalitička aktivnost u reakciji cijepanja vode. Kod 2 spoja je uočen fotokromizam, odnosno termokromizam kod 1.The reactions of building block A3[ML3]·3H2O {A = K+, NH4+ or [(C4H9)4N)4]+; M = Cr3+ or Fe3+; L = C2O42– or C6O4Cl22–}, copper(II) salt and N-donor ligand (imidazole, 2,2'-bipyridine, 1,10-phenanthroline or 2,2':6',2"-terpyridine), with the addition of tetrachloroquinone and KI in some reactions were studied, in layering technique or in hydrothermal conditions. 51 new compounds were prepared: 35 oxalate-based {29 heterometallic [19 (CuIICrIII) and 10 (CuIIFeII/III)]}, and 12 chloranilate {7 heterometallic [4 (CuIICrIII) and 3 [CuIIFeIII]} were isolated. In these reactions 9 complexes with mononuclear, 11 with dinuclear, 5 with trinuclear, 2 with tetranuclear and 1 with hexanuclear units were obtained. 13 one-dimensional and 6 three-dimensional coordination polymers were formed. IR and structural characterization was done for all the complexes. For 15 compounds thermal properties were investigated, for 14 compounds with bridging oxalate group magnetic properties, and for 7 compounds electric properties were studied. 5 selected heterometallic oxalate complexes were tested as molecular precursors for mixed-metal oxides and single-phased CuCrO2 was obtained. Its photocatalytic activity in water splitting reaction was tested. 2 compounds showed photochromism and 1 thermochromism

Magnetic and Electrical Behaviors of the Homo- and Heterometallic 1D and 3D Coordination Polymers Based on the Partial Decomposition of the [Cr(C2O4)3]3− Building Block

One-dimensional (1D) oxalate-bridged homometallic {[Mn(bpy)(C2O4)]·1.5H2O}n (1) (bpy = 2,2’-bipyridine) and heterodimetallic {[CrCu3(bpy)3(CH3OH)(H2O)(C2O4)4][Cu(bpy)Cr(C2O4)3]·CH2Cl2·CH3OH·H2O}n (2) coordination polymers, as well as the three-dimensional (3D) heterotrimetallic {[CaCr2Cu2(phen)4(C2O4)6]·4CH3CN·2H2O}n (3) (1,10-phenanthroline) network, have been synthesized by a building block approach using a layering technique, and characterized by single-crystal X-ray diffraction, infrared (IR) and impedance spectroscopies and magnetization measurements. During the crystallization process partial decomposition of the tris(oxalato)chromate(III) happened and 1D polymers 1 and 2 were formed. The antiferromagnetic interactions between the manganese(II) ions were mediated by oxalate ligands in the chain [Mn(bpy)(C2O4)]n of 1, with intra-chain super-exchange interaction ? = (−3.134 ± 0.004) K; magnetic interaction between neighbouring chains is negligible making this system closer than other known Mn-chains to the ideal 1D Heisenberg antiferromagnet. Compound 2 comprises a 1D coordination anion [Cu(bpy)Cr(C2O4)3]nn− (Cr2–Cu4) with alternating [Cr(C2O4)3]3− and [Cu(bpy)]2+ units mutually bridged through the oxalate group. Another chain (Cr1–Cu3) is similar, but involves a homodinuclear unit [Cu(bpy)(H2O)(µ-C2O4)Cu(bpy)(CH3OH)]2+ (Cu1–Cu2) coordinated as a pendant group to a terminal oxalate oxygen. Magnetic measurements showed that the Cu1−Cu2 cationic unit is a strongly coupled antiferromagnetic dimer, independent from the other magnetic ions within ferromagnetic chains Cr1–Cu3 and Cr2–Cu4. A 3D polymer {[CaCr2Cu2(phen)4(C2O4)6]·4CH3CN·2H2O}n (3) comprising three different metal centers (Ca2+, Cr3+ and Cu2+) oxalate-bridged, contains Ca2+ atoms as nodes connected with four Cr3+ atoms through oxalate ligands. The network thus formed can be reduced to an underlying graph of diamondoid (dia) or (66) topology. Magnetization of 3 shows the ferromagnetic oxalate-bridged dimers [CuIICrIII], whose mutual interaction could possibly originate through the spin polarization of Ca2+ orbitals. Compounds 1 and 3 exhibit lower electrical conductivity at room temperature (RT) in comparison to compound 2

Effect of oral antiseptics on the corrosion stability of nickel‐titanium orthodontic alloys

The aim was to explore the influence of the interaction of oral antiseptics and various coatings on the corrosion behavior of nickel‐ titanium (NiTi) orthodontic alloys. NiTi archwires with uncoated, rhodium‐coated, and nitride‐coated surface were exposed to artificial saliva pH 4.8 at the temperature of 37 °C, and to saliva with the addition of three commercial oral antiseptics (Curaspet, Gengigel, and Listerine). Electrochemical impedance spectroscopy and cyclic polarization were performed. Released nickel and titanium ions after a period of 7 days were measured by inductively coupled optical emission spectroscopy. Results demonstrate that the rate and degree of corrosion mainly increase with the addition of antiseptics. Electrochemical impedance spectroscopy indicates the biggest corrosion resistance in Gengigel. Rhodium‐coated NiTi demonstrates higher corrosion rate in saliva and in all antiseptics than uncoated and nitride‐ coated NiTi. The highest tendency toward localized corrosion is seen in rhodium‐coated NiTi in all media, and least in nitride‐coated NiTi. The release of titanium ions mainly supports findings of general corrosion rate. These results indicate that both antiseptics and coating modify corrosion

Ladder-like [CrCu] coordination polymers containing unique bridging modes of [Cr(C2O4)3]3− and Cr2O72−

Three heterometallic one-dimensional (1D) coordination polymers {; ; ; A[CrCu2(bpy)2(C2O4)4]·H2O}; ; ; n [A = K+ (1) and NH4+ (2) ; bpy = 2, 2’-bipyridine] and [(Cr2O7)Cu2(C2O4)(phen)2]n (3 ; phen = 1, 10- phenanthroline) with uncommon topology have been synthesized using a building block approach and characterized by single-crystal X- ray diffraction, IR and impedance spectroscopies, magnetization measurements, and DFT calculations. Due to the partial decomposition of the building block [Cr(C2O4)3]3−, all three compounds contain oxalate-bridged [Cu2(L)2(μ-C2O4)]2+ units [L = bpy (1 and 2) and phen (3)]. In compounds 1 and 2 these cations are mutually connected through oxalate groups from [Cr(C2O4)3]3−, thus forming ladderlike topologies. Unusually, three different bridging modes of the oxalate ligand are observed in these chains. In compound 3 copper(II) ions from cationic units are bridged through the oxygen atoms of Cr2O72− anions in a novel ladder-like mode. Very strong antiferromagnetic coupling observed in all three compounds, determined from the magnetization measurements and confirmed by DFT calculations (J = −343, −371 and −340 cm−1 for 1, 2 and 3, respectively), appears between two copper(II) ions interacting through the oxalate bridge