2-(1′-Pyrenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (PyrNN) was reacted with M(hfac)2 (M = Mn(II) and Co(II), hfac = hexafluoracetylacetonate) to give two isostructural ML2 stoichiometry M(hfac)2(PyrNN)2 complexes and a ML stoichiometry one-dimensional (1-D) polymer chain complex [Mn(hfac)2(PyrNN)]. The ML2 complexes have similar crystal structures with monoclinic unit cells, in which one NO unit from each PyrNN ligand is bonded to the transition metal on cis vertices of a distorted octahedron. The major magnetic interactions are intracomplex metal-to-radical exchange (J), and intermolecular exchange across a close contact between the uncoordinated NO units (J′). For M = Mn(II) an approximate chain model fit gives g = 2.0, J = (−)125 cm–1 and J′ = (−)49 cm–1; for M = Co(II), g = 2.4, J = (−)180 cm–1, and J′ = (−)70 cm–1. Hybrid density functional theory (DFT) computations modeling the intermolecular exchange by using only the radical units across the close contact are in good accord with the estimated values of J′. The chain type complex structure shows solvent incorporation for overall structure [Mn(hfac)2(PyrNN)]n·0.5(CHCl3)·0.5(C7H16). Both NO groups of the PyrNN ligand are complexed to form helical chains, with very strong metal to radical antiferromagnetic exchange that gives overall ferrimagnetic behavior.

The reaction of K2[PtCl4] and HO(H)NCMe2CMe2N(H)OH·H2SO4 (BHA·H2SO4; 2) in a molar ratio 1:2 at 20−25 °C in water affords a mixture of [Pt(BHA)2][PtCl4] (5) and [Pt(BHA-H)2] (6) (BHA-H = anionic monodeprotonated form of BHA) which, upon heating at 80−85 °C for 12 h or on prolonged keeping at 20−25 °C for 2 weeks, is subject to a slow transformation giving [PtCl2(BHA)] (7). The latter compound is also obtained from the reaction between K[PtCl3(Me2SO)] and 2. The chlorination of [PtCl2(BHA)] (7) in freshly distilled dry chloroform leads to the selective oxidation of one N(H)OH group yielding [PtCl2{HO(H)NCMe2CMe2N=O}] (13), while the chlorination in water produces the complex [PtCl2(O=NCMe2CMe2N=O)] (14) bearing the unexplored dinitrosoalkane species. Treatment of 14 with 2 equiv of 1,2-bis-(diphenylphosphino)ethane (dppe) in CH2Cl2 results in the liberation of the dinitrosoalkane ligand followed by its fast cyclization giving the α-dinitrone (3,3,4,4-tetramethyl-1,2-diazete-1,2-dioxide) in solution and the solid [Pt(dppe)2](Cl)2. The PtII complexes with hydroxylamino∩oximes [PtCl2{HO(H)NC(Me)2C(R)=NOH}] (R = Me 8; R = Ph 9) upon their oxidation with Cl2 in CHCl3 afford the nitrosoalkane derivatives [PtCl2{O=NCMe2C(R)=NOH}] (R = Me 16; Ph 17), respectively, while the corresponding chlorination of the bis-chelates [Pt{HO(H)NCMe2C(R)=NOH}2] (R = Me 10; Ph 11) gives [Pt{O=NCMe2C(R)=NO}2] (R = Me 18; Ph 19). The formulation of 5−19 is based on C, H, and N microanalyses, IR, 1D (1H, 13C{1H}, 195Pt) and 2D (1H,1H-COSY,1H,13C-HSQC) NMR spectroscopies, and X-ray diffraction for five complexes (5, 7, and 12−14).

2-(1′-Pyrenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (PyrNN) was reacted with M(hfac)2 (M = Mn(II) and Co(II), hfac = hexafluoracetylacetonate) to give two isostructural ML2 stoichiometry M(hfac)2(PyrNN)2 complexes and a ML stoichiometry one-dimensional (1-D) polymer chain complex [Mn(hfac)2(PyrNN)]. The ML2 complexes have similar crystal structures with monoclinic unit cells, in which one NO unit from each PyrNN ligand is bonded to the transition metal on cis vertices of a distorted octahedron. The major magnetic interactions are intracomplex metal-to-radical exchange (J), and intermolecular exchange across a close contact between the uncoordinated NO units (J′). For M = Mn(II) an approximate chain model fit gives g = 2.0, J = (−)125 cm–1 and J′ = (−)49 cm–1; for M = Co(II), g = 2.4, J = (−)180 cm–1, and J′ = (−)70 cm–1. Hybrid density functional theory (DFT) computations modeling the intermolecular exchange by using only the radical units across the close contact are in good accord with the estimated values of J′. The chain type complex structure shows solvent incorporation for overall structure [Mn(hfac)2(PyrNN)]n·0.5(CHCl3)·0.5(C7H16). Both NO groups of the PyrNN ligand are complexed to form helical chains, with very strong metal to radical antiferromagnetic exchange that gives overall ferrimagnetic behavior.

Three kinds of para-phenylenediamine (PDA) derivatives bearing nitronyl nitroxide (NN) groups were prepared and characterized on the basis of the electrochemical, electron spin resonance (ESR) spectroscopic, absorption spectroscopic, and magnetic susceptibility measurements. It was clarified that the oxidation potential of the central PDA unit is strongly influenced by the numbers of substituted electron–withdrawing NN groups. In addition, the intervalence charge transfer in the central PDA unit was detected in the monocationic states of the PDAs with two NN groups, indicating the coexistence of the localized spins and the delocalized spin on theses molecules. Moreover, pulsed ESR measurements confirmed that the delocalized spin on the central PDA unit and the localized two spins on the NN groups were ferromagnetically coupled in the monocationic states.