Spin crossover in iron(II) complexes of 3,5-di(2-pyridyl)-1,2,4-triazoles and 3,5-di(2-pyridyl)-1,2,4-triazolates

The iron coordination chemistry of 3,5-di(2-pyridyl)-1,2,4-triazoles and 3,5-di(2-pyridyl)-1,2,4-triazolates is reviewed. This includes both mononuclear and dinuclear complexes, and both iron(II) and iron(III) oxidation states. The main focus is on the synthesis, structure and magnetic properties of these complexes.     

Crystal Structure of Diethyl [2,3-Di(Ethoxycarbonyl)-2,3-di(p-nitrophenyl)] Succinate

Controlled free radical polymerization (CFRP) is an effective means to synthesize polymers of predetermined molecular weight, narrow molecule weight distribution and well-defined architecture. One of the most important milestones in the development of CFRP was the discovery of the iniferter (initiation-transfer-termination) reactions1. Iniferter avoi- ds ordinary bimolecular termination and undergoes initiation, chain tran- sfer to the initiator, and primary radical termination, so it may…     

The reduction products of 2-phenyl-1,3-di(4-pyridyl)-2-propanol

A number of chemical modifications of 2-phenyl-1,3-di(4-pyridyl) - 2 - propanol are described. Dehydration, alkylation and hydrogenation, concomitant and independent, gave a variety of novel compounds. Independent syntheses produced the related compounds X and XVI which were subjected to some of the same reactions. Structural assignments (spectral) were corroborated by the synthesis of common reaction products.     

Synthesis of 2-phenyl-1,3-di(4-pyridyl)naphthvalene by photoinduced reversible valence isomerization of 2-phenyl-1,3-di(4-pyridyl)naphthalene

2-Phenyl-1,3-di(4-pyridyl)naphthvalene 3a was synthesized by the photoinduced reversible valence isomerization of 2-phenyl-1,3-di(4-pyridyl)naphthalene 2a. Then, 3a was converted into 3-phenyl-1,2-di(4-pyridyl)naphthalene 4a and 2a simultaneously. The t_1/2 of 3a in DMSO-d₆ at 90 °C was 2 h, while that at 110 °C was approximately 10 min.     

Near-infrared absorbing and emitting Ru(II)-Pt(II) heterodimetallic complexes of dpdpz (dpdpz = 2,3-di(2-pyridyl)-5,6-diphenylpyrazine)

The reaction of 2,3-di(2-pyridyl)-5,6-diphenylpyrazine (dpdpz) with K(2)PtCl(4) in a mixture of acetonitrile and water afforded mono-Pt complex (dpdpz)PtCl(2)4 in good yield, with two lateral pyridine nitrogen atoms binding to the metal center. Two types of Ru(II)-Pt(II) heterodimetallic complexes bridged by dpdpz, namely, [(bpy)(2)Ru(dpdpz)Pt(C≡CC(6)H(4)R)](2+) (7-9, R = H, NMe(2), or Cl, respectively) and [(tpy)Ru(dpdpz)Pt(C≡CPh)] (+) (12), were then designed and prepared, where bpy = 2,2'-bipyridine and tpy = 2,2';6',2'-terpyridine. In both cases, the platinum atom binds to dpdpz with a C(∧)N(∧)N tridentate mode. However, the coordination of the ruthenium atom with dpdpz could either be noncyclometalated (N(∧)N bidentate) or cyclometalated (C(∧)N(∧)N tridentate). The electronic properties of these complexes were subsequently studied and compared by spectroscopic and electrochemical analyses and theoretical calculations. These complexes exhibit substantial absorption in the visible to NIR (near-infrared) region because of mixed MLCT (metal-to-ligand-charge-tranfer) transitions from both the ruthenium and the platinum centers. Complexes 7 and 9 were found to emit NIR light with higher quantum yields than those of the mono-Ru complex [(bpy)(2)Ru(dpdpz)](2+) (5) and bis-Ru complex [(bpy)(2)Ru(dpdpz)Ru(bpy)(2)](4+) (13). However, no emission was detected from complex 8 or 12 at room temperature in acetonitrile.     

Reactions of 3-methyl-1-(2-pyridyl)-4-chloro-5-formyl-6,7-dihydroindazole

The reactions of 3-methyl-1-(2-pyridyl)-, 3-methyl-1-phenyl-, and 3-methyl-1,6-diphenyl-4-chloro-5-formyl-6,7-dihydroindazoles with guanidine and benzo- and 3- and 4-pyridinecarbamidines gave the corresponding 8-substituted 1-methyl-3-(2-pyridyl)-and 1-methyl-3-phenyl-4,5-dihydropyrazolo[5,4-h]quinazolines. With acetic anhydride the same indazole derivatives gave the 4-acetoxy-5-formyl derivatives, and with hydroxylamine they gave4-chloro-5-hydroxyiminomethyl-6,7-dihydroindazoles. Thereactionof4-acetoxyl-1-(2-pyridyl)-5-formyl-6,7-dihydroindazole with hydroxylamine gave 8-methyl-6-(2-pyridyl)-4,5-dihydroisoxazolo[5,4-e]indazole, while dehydration of 5-hydroxyiminomethyl-3-methyl-4-chloro-6,7-dihydroindazole gave the 4-chloro-5-cyano derivative. The reaction of the latter with nucleophilic reagents was investigated.Riga Technical University, Riga, Latvia LV-1658. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1209–1213, September, 1998.     

Syntheses Based on 4-Chloro-1-[3,5-di(trifluoromethyl)phenyl]-, 4-Chloro-1-(2,4-difluorophenyl)-5-formyl-3-methyl-6,7-dihydroindazoles,and 4-Chloro-5-formyl-3-methyl-1-(2-pyridyl)-6,7-dihydroindazoles

Vilsmeier formylation of 1-[3,5-di(trifluoromethyl)phenyl]- and 1-(2,4-difluorophenyl)-3-methyl-4-oxo-4,5,6,7-tetrahydroindazoles gave the corresponding 1-aryl-4-chloro-5-formyl-3-methyl-6,7-dihydroindazoles. Reaction of the latter with amidines, o-phenylenediamine, hydrazine, or hydroxylamine gave a series of 1-aryl-3-methyl-6,6-dihydroindazoles annelated at positions 4 and 5. The reaction of 4-chloro-5-formyl-3-methyl-1-(2-pyridyl)-6,7-dihydroindazole with substituted anilines gave 5-arylaminomethylene-4-oxo- or 5-arylaminomethylene-4-arylimino-3-methyl-1-(2-pyridyl)-4,5,6,7-tetrahydroindazoles depending on the molar ratio of reagents and the nucleophilicity of the amines.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 740–750, May, 2005.     

1,4-dibutoxy-2,3-di(4-pyridyl)-8,11,15,18,22,25-hexakis(hexyl)- phthalocyaninato zinc,a self-assembled coordination polymer in the solid state

The title compound forms intermolecular zinc-nitrogen coordinated species in solution and self-assembles to form a coordination polymer in the solid state, the X-ray structure for which shows that the unit cell contains eight macrocycle units in two chains comprising both enantiomeric forms as ABBA/BAAB sequences.     

2,3-二硫苄基-6,7-二(2-氰基乙硫基)四硫富瓦烯的合成及其性质研究

设计合成了2,3-二硫苄基-6,7-二(2-氰基乙硫基)四硫富瓦烯. 以UV-Vis, ¹H NMR, IR, MS和元素分析进行了表征, 测定了产物的循环伏安图. 运用Gaussian 98量子化学程序包, 采用密度泛函 (DFT) 的方法, 在B3LYP/6-31G(d) 水平上对分子的几何构型进行了优化. 计算结果表明, 由于取代基的引入使体系的HOMO能量降低, 分子趋于稳定, 这与分子的设计是一致的.     

两个2-取代-4,6-二吡啶基-1,3,5-三嗪桥联的双核钌配合物的晶体结构、光谱和电化学性质

合成并表征了2个基于2-取代-4,6-二吡啶基-1,3,5-三嗪的双核钌配合物,[Ru₂（OBPT）（bpy）₄]（PF₆）₃·3H₂O·0.5CH₃CH₂OH（1）和[Ru₂（HABPT）（bpy）₄]（PF₆）₄·0.5H₂O（2）,其中bpy=2,2''-联吡啶,HOBPT=2-羟基-4,6-（2-吡啶基）-1,3,5-三嗪,HABPT=2-氨基-4,6-（2-吡啶基）-1,3,5-三嗪。分析了2个配合物的单晶结构,其中,1是单斜晶系C2/c空间群,属于外消旋-（ΔΔ）型;2属于正交晶系Pca2₁空间群,属于内消旋-（ΔΛ）型。单晶结构表明1中的配体HOBPT是脱质子的,而2中的HABPT没有脱质子。2个配合物的电化学和光谱性质呈现明显的不同,所有数据均表明配合物中2个金属中心间存在电子耦合。     

Synthesis and reactions of 1-(2-pyridyl)-3-methyl-4-chloro-5-formyl-6,7-dihydroindazoles

The Vilsmeier formylation of 1-(2-pyridyl)-3-methyl-4-oxo-4,5,6,7-tetrahydroindazole and its 6-phenyl derivative gives 1-(2-pyridyl)-3-methyl-4-chloro-5-formyl-6,7-dihydroindazoles. Reactions of these derivatives with different N- and C-nucleophilic agents, including bisnucleophiles, were studied as a means of obtaining new 4- and 5-functional derivatives of indazole and its condensed systems.Riga Technical University, Riga LV-1658, Latvia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 768–773, June, 1998.     

Electron impact mass spectrometry of 2-(2-pyridyl)-2,3-dihydroxy-5-phenyl-4-pentene

The mass spectrometric behaviour of 2-(2-pyridyl)-2,3-dihydroxy-5-phenyl-4-pentene has been studied with the aid of B/E, B²/E linked scans, exact mass measurements, collisionally activated dissociation mass-analysed ion kinetic energy spectra, and labelling experiments. The primary loss of water is proved to involve both hydroxylic hydrogens, thus suggesting the formation of an epoxidic radical ion and the presence of extensive skeletal rearrangements.     

1-(2-pyridyl)-3,4-dihydro-6,7-dimethoxyisoquinoline and some of its hydrogenated and N-substituted derivatives

The preparation of 1-(2-pyridyl)- and 1-(2-piperidyl)-substituted, partly hydrogenated derivatives of 6,7-dimethoxyisoquinoline is described.