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Reaction of Cu(ClO_4)_2 6H_2O with 1-alkyl-2-(arylazo)imidazole [RaaiR' where R = H(a),Me(b);R' = Me(1),Et(2)] and NaN_3/NH_4SCN(1 :2:2 mole ratio)form mononuclear complexes [Cu(RaaiR')_2(N_3)_2](3,4)and [Cu(RaaiR')_2(SCN)_2].DMF(...
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Reaction of Cu(ClO_4)_2 6H_2O with 1-alkyl-2-(arylazo)imidazole [RaaiR' where R = H(a),Me(b);R' = Me(1),Et(2)] and NaN_3/NH_4SCN(1 :2:2 mole ratio)form mononuclear complexes [Cu(RaaiR')_2(N_3)_2](3,4)and [Cu(RaaiR')_2(SCN)_2].DMF(5,6).The complexes are characterized by elemental,spectral,electrochemical and other physicochemical results.The structures of both the complexes are confirmed by the single crystal X-ray diffraction studies of [Cu(MeaaiEt)_2(N_3)_2](4b)and [Cu(HaaiMe)_2(SCN)_2].DMF(5a).The complexes are reduced to [Cu(RaaiR')_2]~+ by ascorbic acid.However,air oxidation of [Cu(MeaaiEt)_2](ClO_4)in presence of N_3~-/SCN~-produces [Cu(MeaaiEt)_2(N_3/NCS)_2].
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1-Ethyl-2-(p-tolylazo)imidazole [p-Me-C6H4-N=N-C_3H_2N_2- Et-1; TaiEt], an unsymmetrical N,N-blocker, and azide (N3-), a versatile intermediary, coordinate to manganese(II) forming an alternating chain with the formula [Mn(TaiEt)(...
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1-Ethyl-2-(p-tolylazo)imidazole [p-Me-C6H4-N=N-C_3H_2N_2- Et-1; TaiEt], an unsymmetrical N,N-blocker, and azide (N3-), a versatile intermediary, coordinate to manganese(II) forming an alternating chain with the formula [Mn(TaiEt)(N_3)_2]_n (1). The compound crystallizes in the triclinic P space group with a = 7.9297(7) A, b = 9.5883(9) A, c = 11.8366(11) A, = 103.555(2)°, = 105.811(2)°, = 104.280(2)°, and Z = 2. The structure consists of neutral chains in which each manganese(II) center is alternately bridged by two end-on and two end-to-end azide ligands. The unsymmetrical arylazo heterocycle chelator creates a strong distortion around the metal center [N-Mn-N bite 67.7°; Mn-N(azo) distance 2.562 A]. The magnetic properties of 1 have been investigated over the temperature range 2-300 K. Magnetic data are analyzed on the basis of an alternating ferro- and antiferromagnetic Heisenberg chain of the manganese(II) ions, described by the spin Hamiltonian H = -J_1ΣS_(2i)S_(2i+1)-J_2ΣS_(2i+1)S_(2i+2). The J exchange parameters are 2.65 ± 0.12 cm~(-1) and -14.5 ± 0.15 cm~(-1), respectively. Magnetic studies at low temperatures indicate long-range ordering (canting) with a remnant magnetism that vanishes above 40 K. The canting phenomenon has been studied by various techniques including an EPR spectroscopic investigation at different temperatures and appears to be due to the local distortion around each metal center and the π-π stacking in the 3-D network.
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Reaction of M(OAc)_2-4H_2O (M = Mn, Zn) and l-alkyl-2-(arylazo)imidazole [RaaiR' where R = H (a), Me (b); R' = Me (1/3/5), Et (2/4/6)] and NaNCO in methanol at 1 :2:2 mol ratio gave [Mn(RaaiR')2(NCO)_2] (3,4) and [Zn(RaaiR')_2(NCO...
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Reaction of M(OAc)_2-4H_2O (M = Mn, Zn) and l-alkyl-2-(arylazo)imidazole [RaaiR' where R = H (a), Me (b); R' = Me (1/3/5), Et (2/4/6)] and NaNCO in methanol at 1 :2:2 mol ratio gave [Mn(RaaiR')2(NCO)_2] (3,4) and [Zn(RaaiR')_2(NCO)_2](5,6) complexes. The structures of these species were confirmed by single-crystal X-ray studies of 4b and 5a.
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Zn(ClO_4)_2 centre dot 6H_2O reacts with l-alkyl-2-(arylazo)imidazoles [RaaiR', where R = H (a), Me (b); R' = Me (1), Et (2)] affording orange-yellow [Zn(RaaiR')_4](ClO_4)_2 (3,4) complexes. When excess sodium azide is added to th...
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Zn(ClO_4)_2 centre dot 6H_2O reacts with l-alkyl-2-(arylazo)imidazoles [RaaiR', where R = H (a), Me (b); R' = Me (1), Et (2)] affording orange-yellow [Zn(RaaiR')_4](ClO_4)_2 (3,4) complexes. When excess sodium azide is added to the reaction, orange-red, dimeric azido-complexes of the type [Zn(RaaiR')(N_3)(mu-l,1-N_3)]_2 (5,6) are obtained. Both types of complex were characterized. Structures were confirmed by single-crystal X-ray diffraction studies of [Zn(HaaiEt)_4](ClO_4)_2 (3b) and [Zn(HaaiMe)(N_3,)(mu-l,l-N_3)]_2 (5a).
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The reaction of Mn(OAc)2 · 4H2O and 1-alkyl-2-(arylazo)imidazole [RaaiR' where R=H (a), Me (b); R' = Me (1/3/), Et (2/4/)] and NH4NCS in MeOH in a 1:2:2 mole ratio afforded [Mn(RaaiR')2(NCS)2] (3) and (4) complexes. They were cha...
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The reaction of Mn(OAc)2 · 4H2O and 1-alkyl-2-(arylazo)imidazole [RaaiR' where R=H (a), Me (b); R' = Me (1/3/), Et (2/4/)] and NH4NCS in MeOH in a 1:2:2 mole ratio afforded [Mn(RaaiR')2(NCS)2] (3) and (4) complexes. They were characterized by different physicochemical methods and the structure has been confirmed by single crystal X-ray diffraction study for title compound. One of the primary ligands was also characterised by an X-ray diffraction study.
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A new Schiff base, 2-pyridyl bis(pyrazineamino)methane (L1) has been synthesized and characterized by elemental analysis, spectroscopic investigations and singfe crystal X-ray diffraction measurements. Reaction of cobalt(II) perch...
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A new Schiff base, 2-pyridyl bis(pyrazineamino)methane (L1) has been synthesized and characterized by elemental analysis, spectroscopic investigations and singfe crystal X-ray diffraction measurements. Reaction of cobalt(II) perchlorate hexahydrate with two molar equivalents of L1 under ambient conditions resulted concurrent oxidation of divalent Co~(II) metal ion with oxygenation and deamination of the animal polydentate ligand to produce bis[2-pyridyl(pyrazineamino)methanolato]cobalt(III) perchlorate trihydrate designated as [Co(L2)]ClO4.3H2O (1). The complex 1 is also characterized by spectroscopy, elemental analysis and X-ray crystallography. X-Ray crystal structure of the complex cation, [Co(L2)2]~+) shows that the two L2 ligands are coordinated to the central cobalt(III) metal ion in a facial mode to afford a slightly distorted octahedral geometry. The two pyridyl and two pyrazine N atoms constitute the equatorial plane on which the cobalt(III) ion lies whereas methanolate O atoms occupy the axial positions.
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1-Alkyl-2-(arylazo) imidazoles are pi-acidic, bidentate chelating molecules. In acid medium imidazole-N centers are protonated and can extract heavy anions. One such example is the binding with ReO_4~- in acidic medium. 1-Alkyl-2-...
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1-Alkyl-2-(arylazo) imidazoles are pi-acidic, bidentate chelating molecules. In acid medium imidazole-N centers are protonated and can extract heavy anions. One such example is the binding with ReO_4~- in acidic medium. 1-Alkyl-2-(arylazo) imidazolium-perrehenate shows hydrogen obnded 1D network. Inclusion of H_2O into the molecular frame of 1D increases the dimensionality to 2D network.
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2-(Arylazo)pyrimidines (aapm) react with AgNO_3 in methanol and crystallises in single strand right-handed helical coordination polymer,[Ag(aapm)(NO_3)]_n.The X-ray structure determination of Ag[2-(phenylazo)pyrimidine] (papm)(NO_...
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2-(Arylazo)pyrimidines (aapm) react with AgNO_3 in methanol and crystallises in single strand right-handed helical coordination polymer,[Ag(aapm)(NO_3)]_n.The X-ray structure determination of Ag[2-(phenylazo)pyrimidine] (papm)(NO_3)(abbreviated, Ag(papm)(NO_3)) suggests the triangular coordination around Ag(I) which is made up of chelated azoimine,-N=N-C=N-,function from one ligand and the third donor centre is coming from meta-related pyrimidine-N of the adjacent papm of the second Ag(papm)-unit.Teh coordination polymer is propagated through pyrimidine-N->Ag bonding.
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Title complexes have been synthesised on reacting 1-ethyl-2-(arylazo)imidazoles (RL, where R = H, Me, Ome, Cl) with (NH_4)_2[OsCL_6]. Two isomers, blue-violet (isomer-A) and redviolet (isomer-B) of the composition OsCl_2(RL)_2 hav...
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Title complexes have been synthesised on reacting 1-ethyl-2-(arylazo)imidazoles (RL, where R = H, Me, Ome, Cl) with (NH_4)_2[OsCL_6]. Two isomers, blue-violet (isomer-A) and redviolet (isomer-B) of the composition OsCl_2(RL)_2 have been chromatographically separated. IR spectra show the presence of two v(Os-Cl) (300-310 and 320-330 cm~(-1)) and suggest the complexes with cis-OsCl_2 configuration. Three geometrical isomers with cis-OsCl_2 configuration are possible; with consideration of co-ordination pairs in the order of Cl, N [N(imidazole)] and N'[N(azo)] they are cis-tans-cis (ctc), cis-cis-trans (cct) and cis-cis-cis (ccc). The ~1H-NMR spectra identify isomer-A and isomer-B as ctc- and ccc- configurations, respectively. Absorption spectra exhibit multiple MLCT [t_2(Os)->#pi#~*(RL)] transitions in the visible region and the energy of transition follows the order ccc > ctc. Redox studies show Os(III)/Os(II) and Os(IV)/Os(III) couples at 0.4-0.6V and 1.6-1.7 V versus SCE, respectively along with ligand reductions.
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