We study luminescent properties of complexes with 2,1,3-benzothiadiazole-5,6-dithiolate (btdt2-) that combines chromophore heterocyclic unit and chelating thiolate groups. A series of new heteroligand complexes with the general formula [M(dppx)(btdt)] were chosen (M = Pt, Pd; dppx = diphenylphosphinomethane (dppm), diphenylphosphinoethane (dppe) and diphenylphosphinoethilene (dppen). Combined experimental and TD-DFT studies reveal negligible effect of the diphosphine ligands on the absorption spectra of the complexes in the solid state and solutions. The first non-dark absorption band at 410-430 nm is attributed to an intraligand (localized on btdt moiety) transition with a minor contribution of a metal-to-ligand charge transfer. In solid state, all complexes exhibit vibrationally-resolved phosphorescence at room temperature in the range of 650-800 nm with a large Stokes shift of ca. 8800 cm- 1, and with the observed lifetimes of the excited state of 5-110 mu s. The presence of an emission signal for [Pd(dppx)(btdt)] is a rare case of room-temperature phosphorescent Pd complexes. In the THF solutions under an argon atmosphere, only the Pt complexes reveal luminescent signal peaked at 650-800 nm, which is quenched upon contact with air.

This work contributes to luminescent molecular switches featuring several emission pathways, which can be activated by external stimuli. We designed Zn complexes with phenylbenzothiazole-based α-aminomethylphosphine oxide (L) and isolated them as crystalline phases, α-[ZnL2Cl2], [ZnL(EtOAc)Cl2], [ZnL2Cl2]·1.5CH2Cl2, and [ZnL2Cl2]·1.5CHCl3. They feature an intramolecular hydrogen bond of medium strength, capable of excited-state intramolecular proton transfer (ESIPT), as well as able for intersystem crossing between singlet and triplet states. Since neither of these processes is predominant, one or the other can occur depending on a slight change in a molecular geometry. The crystalline phases reveal red-colored ESIPT fluorescence, while a metastable amorphous phase β-[ZnL2Cl2] with a similar structure of the coordination center reveals yellow-colored room-temperature phosphorescence. Combined experimental and quantum-chemical TD-DFT study clarified the dual emission behavior for the polymorphs α-[ZnL2Cl2] and β-[ZnL2Cl2], which is attributed to the high dependence of the probability of the excited-state processes on the geometry of the phenylbenzothiazole moiety. The reversible phase transition, accompanied by the change in the emission mechanism (ESIPT fluorescence vs phosphorescence), can be manipulated by fuming with CHCl3 and Et2O, respectively. We have demonstrated good adhesive properties of the polymer-free β-[ZnL2Cl2] film toward glass and plastic, naked-eye color response to fuming with Et2O, and easy recovery with CHCl3.

2-(2′-aminophenyl)benzothiazole is a readily tunable fluorescent core with widespread applications in coordination chemistry, sensing, light-emitting processes, medicinal chemistry, and catalysis. This review provides an overview of the synthetic methodologies to access 2-(2′-aminophenyl)benzothiazole and its organic derivatives, including various phosphorous and silane pincer ligands. The luminescent properties will be discussed, with a special focus on ESIPT and AIE processes. The coordination of transition metals and lanthanides is presented, as well as their influence on biological and light-emitting properties. 2-(2′-aminophenyl)benzothiazole derivatives have also been employed as sensors for a range of cations and anions due to their various binding modes, as well as for bioimaging purposes. Recently, the first application in photocatalysis has emerged, showing one of the many openings for these organic building blocks in the future.

The dinuclear β-diketiminato complex [L1ClDy(μ-Cl)3DyL1(THF)] (1) (L1 = {2,6-iPr2C6H3-NC(Me)CHC(Me)N-2,6-iPr2C6H3}-) was obtained by reaction of DyCl3 with KL1 in a molar ratio of 1:1 and used for the preparation of the mixed-ligand complex [L1Dy(μ-3,5-Cat)]2 (2) by salt metathesis reaction with 3,5-CatK2 (3,5-Cat -3,5-di-tert-butyl-catecholate). Reactions of 3,5-CatNa2 with [L2LnCl2(THF)2] (Ln3+ = Dy, Y) ligated with the less bulky ligand L2 = {2,4,6-Me3C6H2-NC(Me)CHC(Me)N-2,4,6-Me3C6H2}- afforded the mixed-ligand THF-containing complexes [L2Ln(μ-3,5-Cat)(THF)]2 (Ln3+ = Dy (3a), Y (3b)). All new complexes were fully characterized, and the solid-state structures were determined by single-crystal X-ray diffraction. Magnetic measurements revealed single-molecule magnet behavior for the dysprosium complexes. Sub-Kelvin μSQUID studies confirm the SMM character of the systems, while CASSCF calculation along with simulation of the experimental data yields an antiferromagnetic interaction operating between the Dy3+ ions.

Asymmetric aminoiminophosphorane Ph2P(NHPbt)(=NMes) (HL) is synthesized by the reaction of Pbt–NHPPh2 and MesN3 (Pbt = 2-(benzothiazol-2-yl)phenyl; Mes = mesityl). Then it is used to obtain [Y(L)Cl2(THF)] complex (1, THF - tetrahydrofuran). The compounds are isolated as crystalline phases: HL, HL·0.5PhMe, 1, and 1·PhMe. They are characterized by single crystal X-ray diffraction, NMR, and IR techniques. A hydrogen bond between the hydrogen atom of the NH group bonded to Pbt and the nitrogen atom of the heterocycle is present in HL. In complex 1, all three nitrogen atoms of the ligand coordinate to the yttrium cation and form a planar structure of chelate rings. The π-stacking is observed between the aromatic moieties of the molecules in both HL and complex 1.

Deprotonation of SiMe2(HNPbt)2 proligand (1) by Li(NTms2) (Tms = SiMe3) base results in the formation of SiMe2(LiNPbt)2 (Pbt = 2-(1,3-benzothiazol-2-yl)phenyl) in solution, which further reacts with GdCl3 yielding [Li(THF)4][Gd(SiMe2(NPbt)2)2] complex (2). In an attempt to obtain 2 with the use of n-butyllithium as a base, an unexpected product with an intricate structure - [GdMe2Si(NPbt)(o-NC6H4-C(Bu)2(o-NHC6H4S))(μ-NHPbt)Li(THF)] complex (3) is isolated and structurally characterized. The thiazole ring of one of the substituents of the silandiamide ligand is open in it, while two butyl groups are attached to the thiazole C2 carbon atom. In the reaction of 1 with an excess of butyllithium and YCl3, a product with the ligand also containing the C(Bu)2 moiety is formed, which is shown by 1H NMR. Apart from it, double complex salt [Li(THF)4][Y(SiMe2(NPbt)2)2] (4) crystallized as a solvate with Et2O is isolated from the reaction mixture. In an attempt to obtain a monosubstituted [Y(SiMe2(NPbt))Cl] complex, compound 4·2THF forms along with several crystals of [Y(SiMe2(NPbt)2)2(μ-OBu)2] complex (5) the structure of which is characterized by single crystal X-ray diffraction. The photophysical properties of compound 2 are studied in the THF solution and in the crystalline state.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

We report a three-stage scheme (1) Pbt–NH2 + CS2 → (Pbt–NH)2C=S (1) (Pbt = 4-(1′,3′-benzothiazole-2′-yl)phenyl), (2) 1 + PPh3 + I2 → Pbt–N=C=N–Pbt (2), (3) 2 + Ph2PH → (Pbt–N)(Pbt–NH)CPPh2 (3) for the synthesis of a novel luminescent phosphoguanidine 3 with an unprecedentedly high yield (90

Diamidophosphine tBuP(NHMes)2(H2L) is synthesized by the treatment of tBuPCl2 with two equivalents of KNHMes (Mes = 2,4,6-Me3C6H2). The reaction of H2L with potassium hydride in THF (THF is tetrahydrofuran) affords the anionic form HL− with the hydrogen atom migrating from nitrogen to phosphorus, which is confirmed by the 1H and 31P NMR data. The structure of the formed iminophosphonamidinate anion HL− is determined by X-ray diffraction (XRD) in the crystalline phase of K[K(THF)2](tBuPH(NMes)2)2 · C7H8 (KHL). The reaction of KHL with yttrium chloride gives complex [Y(tBuPH(NMes)2)2Cl] ([Y(HL)2Cl]) in which, according to the XRD data, ligands HL− are in the iminophosphonamidinate PH form. The 1H and 31P NMR spectra confirm that this structure of the complex exists in the solution.

A new iminophosphonamine bearing chromophore 2-(phen-2′-yl)-1,3-benzothiazole substituents was synthesized and introduced into lanthanide complexes. The photophysical properties of the obtained compounds were studied.

In an attempt to synthesize a new iminomethylphosphine, tBuC(Ph2P)=N-Btd (Btd = 2,1,3-benzothiadiazole) by a three-step procedure including (1) NH2-Btd + tBuC(=O)Cl → tBuC(=O)NH-Btd, (2) tBuC(=O)NH-Btd + SOCl2 → tBuC(Cl)=N-Btd, and (3) tBuC(Cl)=N-Btd + Ph2PSiMe3 → tBuC(Ph2P)=N-Btd, it was found that the second step is accompanied by the chlorination of the carbocycle in the benzothiadiazole moiety. The reaction of the imidoyl chloride tBuC(Cl)=N-(7-Cl-Btd) formed in this reaction with Ph2PSiMe3 gave 1,3-iminomethylphosphine tBuC(Ph2P)=N-(7-Cl-Btd) (PC=N). The by-products formed in this step include 1,3-aminomethylphosphine oxide tBuCPh2P(O)NH-(7-Cl-Btd) (POCN) and (Ph2POx)2, resulting from partial oxidation and hydrolysis. The reactions of PC=N and POCN with [Pt(COD)Cl2] (COD = 1.3-cyclooctadiene) were studied. In the case of PC=N, the reaction affords the [Pt(PC=N)2Cl2] complex. In the latter case, cleavage of the P–C bond in POCN takes place, and [PtCl2(Ph2POH)2](POCN) and [Pt(CH3CN)tBuC-NH-(7-Cl-Btd)Cl] are isolated from the reaction mixture. The structures of the new compounds were established by single-crystal X-ray diffraction (CCDC nos 2335150 (tBuC(Cl)N-(7-Cl-Btd)), 2335152 (POCN·Et2O), 2335149 (Ph2POx)2, 2335153 ([Pt(PC=N)2Cl2]), 2335154 ([PtCl2(Ph2POH)2](POCN)), and 2335151 ([Pt(CH3CN)(tBuC-NH-(7-Cl-Bbtd))Cl]).

We have studied 2-(2-aminophenyl)benzothiazole and related derivatives for their photophysical properties in view of employing them as new and readily tunable organic photocatalysts. Their triplet energies were estimated by DFT calculations to be in the range of 52-57 kcal mol-1, suggesting their suitability for the [2+2] photocycloaddition of unsaturated acyl imidazoles with styrene derivatives. Experimental studies have shown that 2-(2-aminophenyl)benzothiazoles comprising alkylamino groups (NHMe, NHiPr) or the native amino group provide the best photocatalytic results in these visible-light mediated [2+2] reactions without the need of any additives, yielding a range of cyclobutane derivatives. A combined experimental and theoretical approach has provided insights into the underlying triplet-triplet energy transfer process.

New silanediamide complexes of rare-earth elements are synthesized: [Dy(Me2Si(NMes)2)(THF)22(μ-Cl)2] (Dy1), [Ln(Me2Si(NMes)2)(THF)22(μ-BH4)2] (Ln2, Ln = Y, Dy), and [Ln(Me2Si(NMes)2)(THF)22 (μ-SPh)2] (Ln3, Ln = Y, Tb, Dy), Mes = 2,4,6-(CH3)C6H2=mesityl. The compounds are isolated as crystalline phases Dy1, Ln2 (Ln = Y, Dy), Y3·2THF, Tb3·2C7H8, Dy3·2THF, and Dy3·2C7H8 and characterized by single crystal X-ray diffraction. All complexes have a binuclear structure; a silanediamide ligand is chelated to each Ln atom, and Cl–, BH_4^- , or SPh– act as bridges. By photoluminescence spectroscopy of the solutions of Tb and Dy complexes in THF it is shown that (Me2Si(NMes)2)2– is an effective ligand antenna, which sensitizes metal-centered emission of these lanthanides.

Синтезированы новые силандиамидные комплексы редкоземельных элементов: [{Dy(Me2Si(NMes)2)(thf)2}2(μ-Cl)2] (Dy1), и [{Ln(Me2Si(NMes)2)(thf)2}2(μ-BH4)2] (Ln2, Ln = Y, Dy) и [{Ln(Me2Si(NMes)2)(thf)2}2(μ-SPh)2] (Ln3, Ln = Y, Tb, Dy), Mes = 2,4,6-(CH3)C6H2 = мезитил. Соединения были выделены в виде кристаллических фаз Dy1, Ln2 (Ln = Y, Dy), Y3·2thf, Tb3·2C7H8, Dy3·2thf и Dy3·2C7H8 и охарактеризованы методом РСА. Все полученные комплексы имеют биядерное строение; к каждому атому Ln хелатно координирован силандиамидный лиганд, а мостиковыми выступают Cl–, BH4– или SPh–. С помощью фотолюминесцентной спектроскопии растворов комплексов Tb и Dy в ТГФ показано, что (Me2Si(NMes)2)2– является эффективным лигандом-антенной, который сенсибилизирует металл-центрированную эмиссию этих лантаноидов.

New silanediamide complexes of rare-earth elements are synthesized: [{Dy(Me2Si(NMes)(2))(THF)(2)}(2)(mu-Cl)(2)] (Dy1), [{Ln(Me2Si(NMes)(2))(THF)(2)}(2)(mu-BH4)(2)] (Ln2, Ln = Y, Dy), and [{Ln(Me2Si(NMes)(2))(THF)(2)}(2) (mu-SPh)(2)] (Ln3, Ln = Y, Tb, Dy), Mes = 2,4,6-(CH3)C6H2=mesityl. The compounds are isolated as crystalline phases Dy1, Ln2 (Ln = Y, Dy), Y32THF, Tb32C(7)H(8), Dy32THF, and Dy32C(7)H(8) and characterized by single crystal X-ray diffraction. All complexes have a binuclear structure; a silanediamide ligand is chelated to each Ln atom, and Cl-, BH4-, or SPh- act as bridges. By photoluminescence spectroscopy of the solutions of Tb and Dy complexes in THF it is shown that (Me2Si(NMes)(2))(2-) is an effective ligand antenna, which sensitizes metal-centered emission of these lanthanides.

The complex formation of the redox-active ligand bis(N, N’-2,6-diisopropylphenyl)-9,10-phenanthrenediimine (DippPDI) with alkaline metal (Li, K) and lanthanide (Sm, Dy) cations is studied. The reduction of DippPDI with an alkaline metal excess affords the dianionic form of the ligand (DippPDA2–), which crystallizes with the potassium cation as the coordination polymer [K2(DippPDA)(Thf)3] (Thf is tetrahydrofuran, THF). The reaction of equimolar amounts of the lithium salt with the dianionic form of the ligand and neutral diimine affords the lithium complex with the radical-anion form (DippPSI•–) crystallized as [Li(DippPSI)(Thf)2]. The samarium(III) complex [SmCp*(DippPDA)(Тhf)] (I) is formed by the reduction ofDippPDI with samarocene [Sm (Thf)2] (Cp* is pentamethylcyclopentadienide): both the samarium(II) cation and Cp*– anion are oxidized in the reaction.DippPDI does not react with similar ytterbocene. The dysprosium(III) complexes are synthesized by the ion exchange reactions between DyI3(Thf)3.5 and potassium or lithium salt with theDippPDA2-dianion. Similar complexes [Dy(DippPDA)I(Thf)2] (IIThf) and [Dy(DippPDA)I(Thf)(Et2O)] () are formed in the reactions with the potassium salt depending on the solvent used: a THF-hexane or a diethyl ether-n-hexane mixture, respectively. The coordination of the dysprosium cation by the π system of the conjugated fragment of the NCCN ligand is observed in IIThf, whereas in this coordination is absent. The reaction with Li2(DippPDA) affords the binary complex salt [Li(Тhf)3(Et2O)][DyI2(DippPDA)(Тhf)] (III, crystallization from a THF-Et2O mixture). The crystallization from THF gives the [Li(Тhf)4][DyI2(DippPDA)(Thf)] salt (III') containing the same anion as III. The structures of all new complexes are studied by X-ray diffraction (XRD, CIF files CCDC nos. 2260307–2260313).

The reaction of samarocene [SmCp*(2)(thf)(n)] (1, Cp* = eta(5)-C5Me5, thf = tetrahydrofuran, n = 0, 2) with a redox-active ligand 9,10-phenanthrenequinone (phenQ) was investigated. Reaction products strongly depend on the reactant ratio and the presence of donor solvent (thf). The 1:1 reaction in toluene leads to the trinuclear complex [Sm3Cp*(3)(phenCat)(3)] (4, phenCat(2-) is a doubly reduced form of phenQ), while in thf, the binuclear complex [Sm2Cp*(2)(phenCat)(2)(thf)(3)] (5) is formed with the same metal-to-ligands ratio Sm:Cp*:phenCat = 1:1:1. The same reaction in hexane leads to a mixture of products with a greater number of {SmCp*(2)} fragments; the major ones are the binuclear complex [Sm2Cp*(4)(phenCat)] (6) and the heterovalent complex [Sm3Cp*(4)(phenCat)(2)] (7), and the minor product is the complex salt [SmCp*(2)](+)[Sm2Cp*(3)(phenCat)(2)](-) ([SmCp*(2)][8](-)). Sm2+ in all cases and the Cp*(-) ligand in most cases are oxidized. Simultaneous crystallization of two stable geometrical isomers of 7 was discovered, differing in the position of one phenCat(2-) ligand. For the reactions in toluene, several byproducts were found: two structurally equivalent complexes with the anion 8(-) as the sole ligand, [Sm(8)(2)] (9) and [K(8)(2)](-) (10(-), crystallized with the samarocenium cation), and a cocrystal of two neutral complexes [Sm2Cp*(3)(phenCat)(thf)(mu-OH)](2)[Sm4Cp*(4)(phenCat)(4)] ((11)(2)12). Complex 12 has the same metal-to-ligands ratio as 4 but has a different total composition. The single-crystal structures are compared with the known ones for bulkier 3,6-bis-t-butyl-o-benzoquinone and reveal a crucial influence of ligand steric properties and interligand pi-stacking on the geometry and composition of the complexes.

N-(2-(diphenylphosphino)ethyl)-4,6,7-trifluoro-2,1,3-benzothiadiazol-5-amine (Ph2PCH2CH2NH-btd-F3 (PCCN)) is prepared by the reaction of 4,5,6,7-tetrafluoro-2,1,3-benzothiadiazole (btd-F4) with 2-(diphenylphosphino)ethyl-1-amine (Ph2PCH2CH2NH2) leading to the nucleophilic substitution of F– by a phosphinamide fragment (Ph2PCH2CH2NH)– in btd-F4. Phase 1 (a product of cocrystallization of PCCN (85