Bis(triphenylphosphine)iminium salts of dioxothiadiazole radical anions : preparation, crystal structures, and magnetic properties

Phenanthroline dioxothiadiazoles are redox active molecules that form stable radical anions suitable for the construction of supramolecular magnetic materials. Herein, the preparation, structures and magnetic properties of bis(triphenylphosphine)iminium (PPN) salts of [1,2,5]thiadiazole[3,4-f][1,10]phenanthroline 1,1-dioxide (L), [1,2,5]thiadiazole[3,4-f][4,7]phenanthroline 1,1-dioxide (4,7-L), 5-bromo-[1,2,5]thiadiazolo[3,4-f][1,10]phenanthroline 2,2-dioxide (BrL), and 5,10-dibromo-[1,2,5]thiadiazolo[3,4-f][1,10]phenanthroline 2,2-dioxide (diBrL) are reported. The preparation of new bromo derivatives of the L: 5-bromo-[1,2,5]thiadiazolo[3,4-f][1,10]phenanthroline 2,2-dioxide (BrL) and 5,10-dibromo-[1,2,5]thiadiazolo[3,4-f][1,10]phenanthroline 2,2-dioxide (diBrL)—suitable starting materials for further derivatization—are described starting from a commercially available and cheap 1,10-phenanthroline. All PPN salts show antiferromagnetic interactions between the pairs of radical anions, which in the case of PPN(diBrL) are very strong (−116 cm−1; using Ĥ = −2JSS type of exchange coupling Hamiltonian) due to a different crystal packing of the anion radicals as compared to PPN(L), PPN(4,7-L), and PPN(BrL)

Magnetization dynamics and coherent spin manipulation of a propeller Gd(III) complex with the smallest helicene ligand

A homoleptic gadolinium(III) complex with the smallest helicene-type ligand, 1,10-phenanthroline-N,N'-dioxide (phendo) [Gd(phendo)(4)](NO3)(3)center dot xMeOH (phendo = 1,10-phenanthroline-N,N'-dioxide, MeOH = methanol), shows slow relaxation of the magnetization characteristic for Single Ion Magnets (SIM), despite negligible magnetic anisotropy, confirmed by ab initio calculations. Solid state dilution magnetic and EPR studies reveal that the magnetization dynamics of the [Gd(phendo)(4)](3+) cation is controlled mainly by a Raman process. Pulsed EPR experiments demonstrate long phase memory times (up to 2.7 mu s at 5 K), enabling the detection of Rabi oscillations at 20 K, which confirms coherent control of its spin state.</p

Prognosis of and Demand on Educated Manpower

One of the many factors which are greatly influencing the development of economic growth is the standard of manpower education. Between the years 1955 - 1966 Poland was not among those countries in Europe which had a rapidly developing higher school system. There is a great demand for educated manpower. The continuous drop in the secondary level age group causes a greater need. The basic aim of national economic development in educated manpower should be higher than the increase in general employment. The problem of planning for educated manpower was taken from the model of J. Tinbergen and H. Correa. The prognosis was given in two variants: 1) on the basis of 46% growth in total production, 2) on the basis of 50% growth of total production. The results in table 5 show that the increase in development in total production is equal in proportion to the increase in educated manpower.Digitalizacja i deponowanie archiwalnych zeszytów RPEiS sfinansowane przez MNiSW w ramach realizacji umowy nr 541/P-DUN/201

Synthesis and characterization of hexa- and nonadecanuclear cyanido - bridged molecular clusters

Metodą samoorganizacji uzyskano cztery nowe bimetaliczne układy dyskretne. Trzy z nich to klastry sześciocentrowe powstałe z oktacyjanoniobianu(IV) i kompleksu [MII(tmphen)2X2]0/2+ (X = Cl- lub cząsteczka rozpuszczalnika; tmphen = 3,4,7,8-tetrametylo-1,10-fenantrolina; M = Mn, Fe, Co) o wzorze [MII(tmphen)2]4[NbIV(CN)8]2•solv (solv – cząsteczki wody i/lub metanolu). Klastry Mn4Nb2, Fe4Nb2, Co4Nb2 (odpowiednio związki 1, 2, 3) scharakteryzowano magnetycznie. Okazało się, że 1, posiada wysoki spin S=18/2 i wykazuje silny efekt magnetokaloryczny, 2 wykazuje dwu etapowe przejście spinowe typu spin crossover (SCO) i efekt fotomagnetyczny w niskich temperaturach, a 3 wykazuje silne sprzężenie spinowo – orbitalne i najprawdopodobniej antyferromagnetyczne oddziaływania wewnątrz cząsteczkowe. Ostatni uzyskany układ (związek 4) stanowi pierwszy przykład dziewiętnastocentrowego klastra o wzorze [Co(1,10-tdapO2)2]6[Co(1,10-tdapO2)]6[Fe(CN)2(μ-CN)4]6[Fe(μ-CN)¬6)]n+ (1,10-tdapO2 = 1,1-diokso[1,2,5]thiadiazolo[3,4-f][1,10]fenantrolina; MeCN = acetonitryl). Taki związek może potencjalnie wykazywać przejścia spinowe z przeniesieniem ładunku, oraz efekt fotomagnetyczny. Dla wszystkich związków rozwiązano struktury na podstawie pomiarów dyfrakcji rentgenowskiej na monokryształach.Four new bimetallic clusters were obtained by the self - assembly method. Three of them comprise of two octacyanoniobate(IV) building blocks and four [MII(tmphen)2]2+ units (M = Mn, Fe, Co), leading to compounds of general formula [MII(tmphen)2]4[NbIV(CN)8]2•solv (solv – solvent molecules, water and/or methanol) 1 (M = Mn), 2 (M = Fe), 3 (M = Co). The magnetic measurements revealed that 1 is a high spin S = 18/2 molecule presenting strong magnetocaloric effect , 2 presents rare gradual two step spin-crossover (SCO) and light induced excited spin state trapping (LIESST) phenomena, and finally 3 presents significant magnetic anisotropy. Last compound, cluster 4 is an unprecendented nonadecanuclear cluster of a simplified formula [Co(1,10-tdapO2)2]6[Co(1,10-tdapO2)]6[Fe(CN)2(μ-CN)4]6[Fe(μ-CN)¬6)]n+ (1,10-tdapO2 = [1,2,5]Thiadiazolo[3,4-f ][1,10]phenanthroline 1,1-Dioxide; MeCN = acetonitryl). Preliminary magnetic measurements reveal charge transfer induced spin transitions (CTIST) and it is expected that 4 will exhibit photomagnetic effect. For all compounds structure was solved by means of single crystal X-ray diffraction measurements

Electroactive dioxothiadiazole ligands in the construction of multifunctional molecular magnets

W pracy zaprezentowano syntezę i charakterystykę pięciu nowych związków opartych na elektroaktywnych ligandach dioksotiadiazolowych [1,1]diokso[1,2,5]tiadiazolo[3,4-f][1,10]fenantrolina (1,10-tdapO2) i [1,1]diokso[1,2,5]tiadiazolo[3,4-f][4,7]fenantrolina (4,7-tdapO2): dwie sole PPN(1,10-tdapO2∙) i PPN(4,7-tdapO2∙), dwa jednocentrowe kompleksy z jonami Co(II) i Co(III), odpowiednio: [CoCl2(1,10-tdapO2)2] i PPN[Co(CN)2(1,10-tdapO2∙)2] oraz dziewiętnastocentrową cząsteczkę [Co(1,10-tdapO2)2]6[Co(1,10-tdapO2)(MeCN)]6[Fe(CN)6]7](BF4)3 (w skrócie Co12Fe7). Związki te przygotowują podłoże do racjonalizacji procesów samoskładania z udziałem ligandów dioskotiadiazolowych. Ponadto PPN[Co(CN)2(1,10-tdapO2∙)2] może zostać użyty jako blok budulcowy drugiej generacji do konstrukcji materiałów funkcjonalnych, natomiast sole PPN+ rodników dioksotiadiazolowych stanowią dobrze rozpuszczalne źródło anionów 1,10-tdapO2∙- i 4,7-tdapO2∙- w polarnych rozpuszczalnikach organicznych. Pomiary magnetyczne wykazały słabe oddziaływania antyferromagnetyczne między rodnikami w obydwu solach. W syntezie klastra Co12Fe7 zastosowano aniony [Fe(CN)6]3-i kationy [CoII(1,10-tdapO2)2]2+ otrzymując kompleks z mostkami FeIII-CN-CoII, tworzącymi strukturę o kształcie gwiazdy. Tego typu mostki znane są z przejścia spinowego indukowanego przeniesieniem ładunku między centrami metalicznymi (z ang. CTIST).Five new compounds based on electroactive dioxothiadiazole ligands: [1,1]dioxo[1,2,5]thiadiazole[3,4-f][1,10]phenanthroline (1,10-tdapO2) and [1,1]dioxo[1,2,5]thiadiazole[3,4-f][4,7]phenanthroline (4,7-tdapO2) are reported. Two salts PPN(1,10-tdapO2∙) and PPN(4,7-tdapO2∙), two mononuclear complexes with cobalt(II) and cobalt(III) ions: [CoCl2(1,10-tdapO2)2] and PPN[Co(CN)2(1,10-tdapO2∙)2] respectively, and a nonadecanuclear cluster [Co(1,10-tdapO2)2]6[Co(1,10-tdapO2)(MeCN)]6[Fe(CN)6]7](BF4)3 (Co12Fe7). These compounds are pioneering the field of rational design and self-asembly of dioxothiadiazole based compounds. Moreover, PPN[Co(CN)2(1,10-tdapO2∙)2] can be used as a secondary building unit for construction of functional materials and PPN+ salts of dioxothiadiazole radicals are soluble sources of 1,10-tdapO2∙-, 4,7-tdapO2∙- anions in common polar organic solvents. Magnetic measurements revealed weak antiferromagnetic interactions between radical molecules in PPN(1,10-tdapO2∙) and PPN(4,7-tdapO2∙). In the synthesis of Co12Fe7 cluster the [Fe(CN)6]3- anions and [CoII(1,10-tdapO2)2]2+ cations were used resulting in the compound built of FeIII-CN-CoII motifs, resembling a hexagonal star. This kind of structural motifs are known for the charge transfer induced spin transition (CTIST)

Visible to near-infrared emission from LnIII(Bis−oxazoline)−[MoV(CN)8]Ln^{III}(Bis-oxazoline)-[Mo^{V}(CN)_{8}] (Ln=Ce-Yb) magnetic coordination polymers showing unusual lanthanide-dependent sliding of cyanido-bridged layers

Complexes of lanthanides(III) (Ce–Yb) with 2,2′-bis(2-oxazoline) (Box) combined with octacyanidomolybdate(V) gave a series of magneto-luminescent coordination polymers, {[LnIII(Box)n(DMF)m][MoV(CN)8]}·x(solvent) (1–12). They are built of cyanido-bridged layers of a mixed 4- and 8-metal rings topology and show unique sliding of layers dependent on a 4f metal ion. For light lanthanides, dominant phase A, {[LnIII(Box)2(DMF)2][MoV(CN)8]}·1.5MeCN (Ln = Ce, 1; Pr, 2; Nd, 3), consists of ideally aligned, not shifted layers, giving large channels (13.7 × 14.0 Å). Intermediate lanthanides reveal phase B, {[LnIII(Box)2(DMF)2] [MoV(CN)8]}·H2O (Ln = Sm, 4; Eu, 5; Gd, 6; Tb, 7; Dy, 8), of smaller pores (8.4 × 10.6 Å) due to layer-H2O hydrogen bonding, which induces sliding of CN–-bridged layers. Heavy lanthanides show phase C, {[LnIII(Box)(DMF)3][MoV(CN)8]}·MeCN (Ln = Ho, 9; Er, 10; Tm, 11; Yb, 12), with large channels (13.7 × 13.7 Å) of a similar size to light lanthanides. This effect comes from the changes in LnIII coordination sphere affecting solvent–layer interactions. Compounds 1–12 reveal diverse emission depending on the interaction between LnIII and Box luminophors. For 2–5, 9, and 12, the ligand-to-metal energy-transfer-induced visible f-centered emission ranging from green for HoIII-based 9, orange from SmIII-based 4, to red for PrIII- and EuIII-containing 2 and 5, respectively. Near-infrared emission was found for 2–4, 9, and 12. Red phosphorescence of Box was detected for GdIII-based 6, whereas the selective excitation of ligand or LnIII excited states resulting in the switchable red to green emission was found for TbIII-based 7. The materials revealed LnIII–MoV magnetic coupling leading to ferromagnetism below 2.0 and 2.2 K for 4 and 7, respectively. The onset of magnetic ordering at low temperatures was found for 6 and 8. Compounds 1–12 form a unique family of cyanido-bridged materials of a bifunctional magneto-luminescence character combined with dynamic structural features

Single-Ion Magnetism in a Three-Dimensional Thiocyanate-Bridged Dysprosium(III) Framework

New three-dimensional (3D) lanthanide framework compounds supported by bridging thiocyanate ligand and K+ cations, K4[Ln(NCS)4(H2O)4](NCS)3(H2O)2(1: Ln = Dy, 2: Ln = Tb, 3: Ln = Gd) have been synthesized. A single-crystal X-ray diffraction study showed that all three compounds were isostructural and crystallized in the I 2/a space group. The K+ ion form 2D layers with thiocyanates which are further linked by [Ln(NCS)4(H2O)4]- complexes and additional thiocyanate ions to generate an interesting 3D framework structure. Compound 1 shows slow magnetic relaxation behavior under a zero direct current (DC) field, indicating that 1 behaves as a single-ion magnet (SIM). As estimated from AC magnetic measurements, the effective energy barrier for spin reversal in 1 was Ueff = 42 cm–1. Slow relaxation of magnetization under a small external DC field was also detected for 2 and 3 at 1.8 K