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Reduction of (NP)PCl2 (NP=phosphinoamidinate [PhC(NAr)(=NPPri2)]−) with KC8 affords the phosphinoamidinato‐supported phosphinidene (NP)P (9). Reaction of 9 with a N‐heterocyclic carbene (MeC(NMe))2C: results in the NHC‐adduct NHC→P−P(Pri2)=NC(Ph)=NAr featuring an iminophosphinyl group. Reactions of 9 with HBpin and H3SiPh led to the metathesis products (NP)Bpin and (NP)SiH2Ph, respectively, whereas with HPPh2 a base‐stabilized phosphido‐phosphinidene, the product of N−P and H−P bond metathesis, was obtained. Reaction of 9 with tetrachlorobenzaquinone results in oxidation of P(I) to P(III), accompanied by oxidation of the amidophosphine ligand into P(V). Addition of benzaldehyde to 9 results in a phospha‐Wittig reaction affording a product of P=P and C=O bond metathesis. Related reaction with phenylisocyanate results in a product of N−P(=O)Pri2 addition to the C=N bond of an intermediate iminophosphaalkene to produce a phosphinidene intramolecularly stabilized by a diaminocarbene. [ABSTRACT FROM AUTHOR]

The AlI compound NacNacAl (1, NacNac = [ArNC(Me)CHC(Me)NAr]−, Ar = 2,6‐iPr2C6H3) serves as a template for the chemoselective coupling between carbonyls (benzophenone, fenchone, isophorone, p‐tolyl benzoate, N,N‐dimethylbenzamide, (1‐phenylethylidene)aniline) and pyridine. With the CH‐acidic ketone (1R)‐(+) camphor, the reaction affords a hydrido alkoxide compound of Al, formed as the result of enolization, whereas an enolizable imine, (1‐phenylethylidene)aniline, and the bulky ketone isophorone, still chemoselectively couple with pyridine. In contrast, reaction with the ester p‐tolyl benzoate results in cleavage of the ester bond together with replacement of the alkoxy group by a hydrogen atom of the pyridine moiety. This study demonstrates that for carbonyl substrates featuring phenyl substituents, the reaction proceeds via intermediate formation of η2(C,X)‐coordinated (X = O, N) carbonyl adducts, whereas the reaction of 1 with (R)‐(−)‐fenchone in the absence of pyridine leads to CH activation in the pendant isopropyl group of the Ar substituent of the NacNac ligand. [ABSTRACT FROM AUTHOR]

[Display omitted] The reactivity of an aluminium(I) diketiminate compound NacNacAl (NacNac is [ArNC(Me)CHC(Me)NAr]−, where Ar is 2,6-diisopropylphenyl) towards arenes has been systematically explored. Heating NacNacAl in benzene results in a fragmentation of the NacNac moiety due to cleavage of the C N bond, while anthracene adds to the main group carbenoid in a [4+1] fashion. Reactions with phenanthrene, triphenylene and fluoranthene demonstrate a reversible [4+1] addition process. [ABSTRACT FROM AUTHOR]

The aluminum(I) compound NacNacAl (NacNac=[ArNC(Me)CHC(Me)NAr]−, Ar=2,6‐iPr2C6H3, 1) shows diverse and substrate‐controlled reactivity in reactions with N‐heterocycles. 4‐Dimethylaminopyridine (DMAP), a basic substrate in which the 4‐position is blocked, induces rearrangement of NacNacAl by shifting a hydrogen atom from the methyl group of the NacNac backbone to the aluminum center. In contrast, C−H activation of the methyl group of 4‐picoline takes place to produce a species with a reactive terminal methylene. Reaction of 1 with 3,5‐lutidine results in the first example of an uncatalyzed, room‐temperature cleavage of an sp2 C−H bond (in the 4‐position) by an AlI species. Another reactivity mode was observed for quinoline, which undergoes 2,2′‐coupling. Finally, the reaction of 1 with phthalazine produces the product of N−N bond cleavage. [ABSTRACT FROM AUTHOR]

The aluminum(I) compound NacNacAl (NacNac=[ArNC(Me)CHC(Me)NAr]−, Ar=2,6‐iPr2C6H3, 1) shows diverse and substrate‐controlled reactivity in reactions with N‐heterocycles. 4‐Dimethylaminopyridine (DMAP), a basic substrate in which the 4‐position is blocked, induces rearrangement of NacNacAl by shifting a hydrogen atom from the methyl group of the NacNac backbone to the aluminum center. In contrast, C−H activation of the methyl group of 4‐picoline takes place to produce a species with a reactive terminal methylene. Reaction of 1 with 3,5‐lutidine results in the first example of an uncatalyzed, room‐temperature cleavage of an sp2 C−H bond (in the 4‐position) by an AlI species. Another reactivity mode was observed for quinoline, which undergoes 2,2′‐coupling. Finally, the reaction of 1 with phthalazine produces the product of N−N bond cleavage. [ABSTRACT FROM AUTHOR]

Three macrocyclic complexes DyCl 3 (N 5 )·4H 2 O ( 4 ), DyCl 3 (N 3 O 2 )·6H 2 O ( 5 ) and DyCl 3 (db-N 3 O 3 )·6H 2 O ( 6 ) (where db = dibenzo) have been prepared in which the Dy III ion is equatorially bound by the Schiff-base macrocycles conferring a pseudo - D 5h geometry on complexes 4 and 5 that is supported by TGA, molar conductance measurements, as well as Raman and far-IR spectroscopy. In contrast the coordination geometry of 6 is less clear with analytical data supporting 7-, 8- or 9-coordination depending on whether the L 3 macrocycle chelates in a tetra-, penta- or hexa-dentate manner. For all three complexes, ac susceptibility data reveal slow relaxation of the magnetisation in zero field below 15 K with a distribution of relaxation rates. [ABSTRACT FROM AUTHOR]

Oxidation of a base‐stabilized phosphinidene (κ2‐NNP)P (12, NNP=phosphinoamidinate) with N2O afforded a labile phosphinidene oxide (κ2‐NNP)P=O (16) which was characterized by NMR spectroscopy. Further oxidation of 16 by N2O or reaction of 12 with two equivalents of pyridine oxide afforded the isolable dioxide (κ2‐NNP)PO2 which was characterized by NMR and SC XRD. Trapping of 16 with tolyl isocyanate resulted in P=O/N=C metathesis, eventually affording a urea‐ligated phosphine (κ1‐NNP)P(NTol)2C=O (17) The mechanism of this reaction was elucidated by DFT calculations. Reactions of phosphinidene 12 with azides generated transient imines (NNP)P=NR, which in the case of R=Tol underwent cycloaddition with tolyl Isocyanate to afford the urea product 17, and in the case of R=SiMe3 reacts with N3SiMe3 via the addition of N−Si across the P=N bond affording, after the extrusion of dinitrogen, a P,N‐heterocyclic compound. Both products of the reactions with azides have been fully characterized, both in solution and the solid‐state. Finally, reaction of phosphinidene 12 with one equivalent of sulfur resulted in the isolation of the base‐stabilized phosphinidene sulfide (κ2‐NNP)P=S that has also been fully characterized. [ABSTRACT FROM AUTHOR]

A novel bidentate amine‐imine ligand precursor LH has been synthesized. This compound was reacted with ZnMe2 to generate the zinc methyl complex, LZnMe (4). The latter compound was fully characterized by NMR spectroscopy and single crystal X‐ray diffraction. Compound 4 is a catalyst for the hydroboration and hydrosilylation of N‐heterocycles, but with moderate catalytic activity. A more active catalyst, the zinc hydride complex LZnH (5) was synthesized by reacting the lithium salt LLi with ZnCl2 followed by sequential reaction with tBuOK and PhMeSiH2. Compound 5 catalyzes the selective 1,2‐hydroboration of nitrogen heteroaromatics with decreased catalyst load and under mild conditions. Deuterium‐labeling experiments and kinetic studies provided insight into the possible reaction mechanism. It is proposed that hydride transfer to the substrate proceeds directly from the reductant (borane) via a six‐membered transition state facilitated by the catalyst, in which it plays an ambiphilic role, activating the substrate via coordination to the Lewis acidic zinc and enhancing the hydricity of the borane through coordination to the zinc hydride. [ABSTRACT FROM AUTHOR]

The preparation and characterization of a novel chiral macrocycle S,S-[FeII(PhCH2OCH2)2(N3O2)(CN)2] (4) is presented. Magnetic susceptibility studies reveal that this complex undergoes a gradual spin crossover in the solid state with no thermal hysteresis. Variable temperature X-ray diffraction studies on single crystals of 4 reveal that at 150 K the complex is comprised of two crystallographically independent octahedral Fe(ii) centres. Warming the crystal to 300 K results in a subtle change in coordination geometry of one of the octahedral Fe(ii) centers towards a 7-coordinate, pentagonal bipyramidal geometry that is accompanied by a conformation change in one of the PhCH2OCH2 substituents. [ABSTRACT FROM AUTHOR]

Two classes of complexes of 15-membered Schiff base macrocycles with a pentadentate (N 3 X 2 ) cavity (where X = O, N, S) prepared via a metal templated condensation reaction between suitably functionalized 2,6-diacetylpyridine and polyamines are surveyed. The structures and properties of transition metal and lanthanide complexes are presented. Particular emphasis is placed on the unique structural changes accompanying the thermal and light induced spin crossover transition of a [Fe(N 3 O 2 )(CN) 2 ] complex as well as a detailed exploration of Mn(II) complexes that in addition to their magnetic properties have been investigated for potential applications in biomedical diagnostics, as enzyme mimics for superoxide dismutase as well as for their antimicrobial activity. The remarkable versatility of this family of complexes as building blocks for the self-assembly of discrete and polymeric systems which include clusters, chains and photoswitchable molecule-based magnets is also reviewed. [ABSTRACT FROM AUTHOR]

The use of a previously unexplored Schiff-base ligand in Ni(II) carboxylate chemistry has afforded a Ni26 cluster with a record nuclearity that crystallizes with a unique 'rabbit-face'-like topology, and a Ni18 compound that adopts an unusual 'molecular chain' structure. [ABSTRACT FROM AUTHOR]

The spin-spin interactions in a complex consisting of a metalloporphyrin with a verdazyl radical attached at one of the β positions of the porphyrin ring are investigated. The X-ray crystal structure of the copper porphyrin complex shows that the plane of the verdazyl moiety is oriented such that it is ready perpendicular to the plane of the porphyrin ring so that weak magnetic interactions between the metal and radical ace expected. Consistent with this expectation, magnetic susceptibility and continuous-wave electron paramagnetic resonance (EPA) measurements of the copper (d9) and vanadyl (&) versions of the porphyrin show that the metal and radical are weakly antiferroniagnetically coupled. Thus, the ground state is a single, but the triplet state is thermally accessible above ∼5 K. Spin-polarized transient EPR measurements of the tree-base analogue show that its lowest excited state is a quartet, indicating that the verdazyl radical couples ferromagnetically to the triplet excited state of the porphyrin. Low-temperature transient EPA measurements on the vanadyt porphyrin reveal that the lowest excited quintet state is populated. This implies that the antiferromagnetic coupling between the metal and radical observed in the ground state is switched to a ferromagnetic arrangement in the excited state by the presence of the unpaired electrons in the π and π orbitals of the porphyrin. [ABSTRACT FROM AUTHOR]

A high‐nuclearity {Ni18} complex (1) with a unique ‘flying saucer’ motif has been prepared from the organic chelate, α‐methyl‐2‐pyridine‐methanol (mpmH), in conjunction with bridging azido (N3−) and peroxido (O22−) ligands. Magnetic susceptibility measurements revealed the presence of both ferro‐ and antiferromagnetic exchange interactions between the metal centres in 1, and the stabilization of spin states with appreciable S values at two different temperature regimes. The end‐on bridging azido and alkoxido groups are in all likelihood the ferromagnetic mediators, while the η3:η3:μ6‐bridging peroxides most likely promote the antiparallel alignment of the metals’ spin vectors, yielding an overall non‐zero spin ground state for the centrosymmetric compound 1. Furthermore, the {Ni18} nanosized cluster behaves as a single‐molecule magnet, exhibiting magnetic hysteresis at low temperatures and two relaxation processes at 15 K and 1.3 K, a very rare phenomenon in polynuclear magnetic 3d‐metal clusters. [ABSTRACT FROM AUTHOR]

Reactions of silicon and germanium dichlorides L⋅ECl2 (E=Si, L=IPr; E=Ge, L=dioxane) with the phosphinoamidinato‐supported disilylene ({κ2(N,P)‐NNP}Si)2 resulted in formal tetrylene insertions into the Si−Si bond. In the case of the reaction with silylene, two products were isolated. The first product ({κ2(N,P)‐NNP}Si)2SiCl2, is the formal product of direct SiCl2 insertion into the Si−Si bond of ({κ2(N,P)‐NNP}Si)2 and thus features two separated silylamido silylene centers. Over time, migration of the SiCl2 group to a lateral position afforded the second product, the disilylene {κ2(Si,P)−SiCl2NNP}Si−Si{κ2(N,P)‐NNP}. In contrast, insertion of GeCl2 resulted only in the isolation of the germanium analogue of {κ2(Si,P)−SiCl2NNP}Si−Si{κ2(N,P)‐NNP}, containing a Ge atom in the central position namely, compound {κ2(Si,P)−SiCl2NNP}Ge−Si{κ2(N,P)‐NNP}, which is a rare example of a silylene‐germylene. Finally, reaction of disilylene ({κ2(N,P)−NNP}Si)2 with SiCl4 and SiHCl3 led to the formation of the new bis(silyl)silylene, ({NNP}SiCl2)2Si:. All four new products from these insertion reactions have been characterized by multinuclear NMR and single‐crystal X‐ray diffraction studies. [ABSTRACT FROM AUTHOR]

The germylone dimNHCGe (5, dimNHC=diimino N‐heterocyclic carbene) undergoes a [2+2] cycloaddition with isocyanates RNCO (R=4‐tolyl or 3,5‐xylyl) to furnish novel alkyl carboxamido germylenes 7 (R=4‐tolyl) and 8 (R=3,5‐xylyl), featuring a C−C bond between the former carbene carbon and the isocyanate moiety. Heating a mixture of 8 with 4‐tolyl isocyanate to 100 °C results in isocyanate metathesis, demonstrating reversible C−C bond formation on the reduced germanium compound. DFT calculations suggest that this process occurs via the reductive dissociation of isocyanate from 8 that regenerates the parent Ge(0) compound 5. [ABSTRACT FROM AUTHOR]

An unsymmetrical guanidine‐cyclopropenimine proton sponge DAGUN and the related BF2‐chelate DAGBO are reported. Insight into the structural, electronic, bonding and photophysical properties of these two molecules are presented. Joint experimental and theoretical studies reveal the protonated form of DAGUN possesses an intramolecular N⋅⋅⋅H−N hydrogen bond which affords a high experimental pKBH+ of 26.6 (computed=26.3). Photophysical studies show that in solution DAGUN displays a green emission at 534 nm, with a large Stokes shift of 235 nm (14,718 cm−1). In contrast, the conjugate acid DAGUN‐H+ is only weakly emissive due to attenuated intramolecular charge transfer. X‐ray diffraction studies reveal that DAGBO contains a stable tetracoordinate boronium cation, reminiscent of the well‐established BODIPY family of dyes. In solution, DAGBO exhibits a strong blue emission at 450 nm coupled with a large Stokes shift (Δλ=158 nm, Δν=11,957 cm−1) and quantum yield of 62 %, upon excitation at 293 nm. DAGBO sets the stage as the first entry into a new class of boron‐difluoride diaminonaphthalenes (BOFDANs) that represent highly fluorescent and tunable next‐generation dyes with future promise for biosensing and bioimaging applications. [ABSTRACT FROM AUTHOR]

A linear Cu 4 complex containing a combination of square pyramidal and octahedrally coordinated Cu(II) ions is reported. The metal centres are linked via diazine and chloride bridges. Magnetic studies reveal the presence of strong antiferromagnetic interactions via the diazine bridge and moderate ferromagnetic interactions via the chloro bridges. The pyrimidinyl hydrazone ligand O C{NHN C(Me)(pm)} 2 (pm = 2-pyrimidinyl) (L 3 H 2) has two potentially protic H atoms and multiple donor atoms. The reaction of L 3 H 2 with CuCl 2 ·2H 2 O yielded the tetranuclear complex [Cu 4 (L 3 H) 2 Cl 6 (CH 3 OH) 2 ] (1). Structural studies on 1 reveal the molecule is located about a crystallographic inversion centre, affording two crystallographically independent Cu(II) centres with the two symmetry equivalent [Cu 2 (L 3 H)Cl 3 CH 3 OH] units connected via µ 2 -Cl bridges to generate a linear tetranuclear copper complex. The ligand is singly deprotonated (L 3 H−) and twisted around the diazine N N′ bond, affording an N 3 donor set for the Cu1 centre and an N 2 O donor set for the Cu2 centre. The Cu1 ion is five coordinate with an [N 3 ] donor set from the L 3 H− ligand and the remaining two sites occupied by Cl− anions. The Cu2 ion is six coordinate with the L 3 H− ligand offering a mer [N 2 O] donor set, with the three remaining sites occupied by two Cl− anions and a MeOH molecule. Magnetic studies reveal the presence of strong antiferromagnetic interactions via the diazine bridge linking the Cu1 and Cu2 ions and moderate ferromagnetic interactions via the chloro bridges located about the inversion centre, connecting the Cu2 and Cu2i ions. [ABSTRACT FROM AUTHOR]

Cover Feature: Base-Stabilized Phosphinidene Oxide, Imide and Sulfide (Chem. Eur. J. 59/2023) Iminophosphorane, phosphinidene, phosphinidene imide, phosphinidene oxide, phosphinidene sulfide Keywords: Iminophosphorane; phosphinidene; phosphinidene imide; phosphinidene oxide; phosphinidene sulfide EN Iminophosphorane phosphinidene phosphinidene imide phosphinidene oxide phosphinidene sulfide 1 1 1 10/26/23 20231023 NES 231023 B Phosphinidene conducts an auction for the best P=X bond b : Cyclic phosphinoamidinate-supported phosphinidene (NP)P is a natural precursor to base-stabilized P SP III sp compounds (NP)P=X (X=O, NR, S). [Extracted from the article]

Reaction of NacNacGa with phenylisocyante generates a transient species amenable to unusual 1,3-C–H bond addition of unactivated sp3 C–H and sp2 C–H bonds of substrates featuring a hard donor atom. This reaction proceeds for pyridine oxide, dimethylsulfoxide, and dimethylacetamide, but not for pyridine, cyclohexanone, and ethyl acetate. C–H activation was also not observed for reactions with triethylphosphine oxide but, interestingly, in the presence of this compound isocyanate undergoes self-coupling on Ga(I) with a regioselectivity that is different when carried out in the absence of Et3PO. [ABSTRACT FROM AUTHOR]

The germylone dimNHCGe (dimNHC=diimino N‐heterocyclic carbene) reacts with azides N3R (R=SiMe3 or p‐tolyl) to furnish the first examples of germanium π‐complexes, i. e. guanidine‐ligated compounds (dimNHI−SiMe3)Ge (NHI=N‐heterocyclic imine, R=SiMe3) and (dimNHI−Tol)Ge (R=p‐tolyl). DFT calculations suggest that these species are formed by a Staudinger type replacement of dinitrogen in the azide by a nucleophilic germylone, leading to a transient carbene adduct of iminogermylidene. Heating a solution of compound (dimNHI−SiMe3)Ge to 70 °C results in extrusion of the iminogermylidene that further aggregates to produce the known [Me3SiNGe]4 tetramer, whereas the imidazolylidene fragment transforms into an unusual heptatriene species that can be considered as a product of carbene insertion into the C−C bond of a pendant Ar substituent at the imidazolylidene nitrogen of the dimNHC. Reaction of (dimNHI−SiMe3)Ge with tetrachloro‐o‐benzoquinone results in the net transfer of a germanium atom and formation of the free diimino‐guanidine ligand. This ligand also forms when (dimNHI−SiMe3)Ge is treated with azide N3(p−Tol), with the germanium product being [(p−Tol)NGe]n [ABSTRACT FROM AUTHOR]

Diimino−carbene‐supported germylone dimNHCGe does not react with BPh3 and does not activate dihydrogen in the FLP mode in the combination with this borane. However, it reacts with B(C6F5)3 to give the zwitterionic borate dimNHCGe−(C6F4)BF(C6F5)2. This compound can be converted into the hydroborate dimNHCGe−(C6F4)BH(C6F5)2 (8) and further into [dimNHCGe−(C6F4)B(C6F5)2]+ (4). Compound 4 is a Ge/B analogue of Stephan's FLP parent P/B compound (C6H2Me3)2P−C6F4−B(C6F5)2 but unlike the latter cannot split dihydrogen. Moreover, attempts to prepare a Ge/B analogue of the zwitterion (C6H2Me3)2HP−C6F4−BH(C6F5)2 by protonation of borate 8 resulted in immediate elimination of H2. [ABSTRACT FROM AUTHOR]

Review: 141 refs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Syntheses of a series of dibromo- and diiodo-BODIPY derivatives. • Compared photostability and photosensitization efficiency of BODIPY derivatives. • Antibacterial activity against B. subtilis by BODIPY containing tertiary amine. A series of 2,6-dibromo-, 2,6-diiodo-4,4-difluoro-4-bora-3a,4a-diaza- s -indacene, together with the 4,4-dicyano analogs were synthesized. The photostability of these BODIPY derivatives and their efficiencies in generating singlet oxygen species were determined. Among these, 2,6-dibromo-4,4-dicyano-4-bora-3a,4a-diaza- s -indacene (BODIPY 6) was found to be similarly photostable as Rose Bengal, while 2,6-diiodo-8-iodomethyl-1,3,5,7-tetramethyl-4,4-difluoro-4-bora-3a,4a-diaza- s -indacene (BODIPY 10) and 1,3,5,7,8-pentamethyl-2,6-diiodo-4,4-dicyano-4-bora-3a,4a-diaza- s -indacene (BODIPY 5) were found to be the least stable. For the ability to generate singlet oxygen species, 2,6-dibromo- (BODIPY 3) and 2,6-diiodo-4,4-difluoro-4-bora-3a,4a-diaza- s -indacene (BODIPY 2) were found to be more efficient than Rose Bengal, while BODIPY 10 and 1,3,5,7,8-pentamethyl-2,6-diiodo-4,4-dicyano-4-bora-3a,4a-diaza- s -indacene (BODIPY 5) were quite poor photosensitizers. When Bacillus subtilus cultures were supplemented with the photosensitizers and exposed to light, it was found that the presence of a positive charge in the photosensitizers was essential in order for them to be effective bacterialcidal agents. [ABSTRACT FROM AUTHOR]

A series of imino-POCNR, amino-POCNR2, and bis(phosphinite) POCOP pincer complexes of Ni(II) were prepared and tested in catalytic deoxygenative hydroboration of amides with HBPin to the corresponding amines. In contrast to the deoxygenative hydrosilylation approach, primarily developed for tertiary amides, superior reactivity in Ni-catalyzed deoxygenative hydroboration was demonstrated for secondary carboxamides. The bis(phosphinite) hydride complex (POCOP)NiH proved the most active in these reactions, tolerating potentially reducible functionalities such as internal alkenes, esters, nitriles, heteroaromatic compounds, and tertiary amides. Preferable hydroboration of secondary amides was also demonstrated in the presence of primary amide functionalities. The reactions were conducted at 60–80 °C, representing a rare example of a base-metal catalytic system for selective deoxygenation of secondary amides to the corresponding amines under mild conditions. In contrast to secondary amides, deoxygenative hydroboration of primary amides was demonstrated using an iminophosphinite pre-catalyst (POCNDmp)Ni(CH2TMS) (Dmp = 2,6-Me2C6H3). Deoxygenation reactions were suggested to proceed via a direct C–O bond cleavage mechanism, which is triggered by dehydrogenative N-borylation to access more electrophilic N-borylamides amenable to the addition of HBPin to the carbonyl group. [ABSTRACT FROM AUTHOR]

A new asymmetrically substituted ONOO Schiff base ligand N-(2′-hydroxy-1′-naphthylidene)-3-amino-2-naphthoic acid (nancH2) was prepared from the condensation of 2–hydroxy–1–naphthaldehyde and 3–amino–2–naphthoic acid. nancH2 reacts with Cu2(O2CMe)4·2H2O in the presence of Gd(O2CMe)3·6H2O to afford a uniform one-dimensional homometallic chain, [CuII(nanc)]n (1). The structure of 1 was elucidated via single crystal X-ray diffraction studies, which revealed that the Cu(II) ions adopt distorted square planar geometries and are coordinated in a tridentate manner by an [ONO] donor set from one nanc2− ligand and an O− of a bridging carboxylate group from a second ligand. The bridging carboxylato group of the nanc2− ligand adopts a syn, anti-η1:η1:μ conformation linking neighboring Cu(II) ions, forming a 1D chain. The magnetic susceptibility of 1 follows Curie–Weiss law in the range 45–300 K (C = 0.474(1) emu K mol-1, θ = +7.9(3) K), consistent with ferromagnetic interactions between S = ½ Cu(II) ions with g = 2.248. Subsequently, the data fit well to the 1D quantum Heisenberg ferromagnetic (QHFM) chain model with g = 2.271, and J = +12.3 K. DFT calculations, implementing the broken symmetry approach, were also carried out on a model dimeric unit extracted from the polymeric chain structure. The calculated exchange coupling via the carboxylate bridge (J = +13.8 K) is consistent with the observed ferromagnetic exchange between neighbouring Cu(II) centres. [ABSTRACT FROM AUTHOR]

A 1,1'‐disubstituted ferrocenyl pyrroloimidazolone with syn stereochemistry undergoes double lithiation–electrophile quench in a one‐pot procedure to give C2‐symmetric 1,1',2,2'‐tetrasubstituted products in >95 : 5 diastereomeric ratio (dr). These results represent an extension of double lithiation to access tetrasubstituted planar chiral ferrocenes for the first time to a nitrogen‐linked (pyrroloimidazolone) chiral directing group. The stereochemistry of the products was determined by X‐ray crystallography of distannane and dibromide adducts in combination with deuteration, elimination, and transmetalation experiments. Results support that products arise from selective deprotonation of the pro‐Sp position of each cyclopentadienyl (Cp) ring. [ABSTRACT FROM AUTHOR]

Keywords: chlorosilanes; disilylenes; insertion; tetrelenes EN chlorosilanes disilylenes insertion tetrelenes 1 1 1 12/20/22 20221215 NES 221215 B Insertion of silylene b : SiCl SB 2 sb into the Si-Si bond of a phosphinoamidinate-supported disilylene affords a SiCl SB 2 sb -bridged bis(silylene) that, upon heating, rearranges into a silyl-substituted disilylene. More information can be found in the Research Article by S. F. Vyboishchikov, G. I. Nikonov and co-workers (DOI: 10.1002/chem.202202799). Front Cover: The Insertion of EII and EIV Chlorides (E=Si, Ge) into the Si-Si Bond of Disilylene (Chem. Eur. J. 70/2022). [Extracted from the article]

Reactions of silicon and germanium dichlorides L⋅ECl2 (E=Si, L=IPr; E=Ge, L=dioxane) with the phosphinoamidinato‐supported disilylene ({κ2(N,P)‐NNP}Si)2 resulted in formal tetrylene insertions into the Si−Si bond. In the case of the reaction with silylene, two products were isolated. The first product ({κ2(N,P)‐NNP}Si)2SiCl2, is the formal product of direct SiCl2 insertion into the Si−Si bond of ({κ2(N,P)‐NNP}Si)2 and thus features two separated silylamido silylene centers. Over time, migration of the SiCl2 group to a lateral position afforded the second product, the disilylene {κ2(Si,P)−SiCl2NNP}Si−Si{κ2(N,P)‐NNP}. In contrast, insertion of GeCl2 resulted only in the isolation of the germanium analogue of {κ2(Si,P)−SiCl2NNP}Si−Si{κ2(N,P)‐NNP}, containing a Ge atom in the central position namely, compound {κ2(Si,P)−SiCl2NNP}Ge−Si{κ2(N,P)‐NNP}, which is a rare example of a silylene‐germylene. Finally, reaction of disilylene ({κ2(N,P)−NNP}Si)2 with SiCl4 and SiHCl3 led to the formation of the new bis(silyl)silylene, ({NNP}SiCl2)2Si:. All four new products from these insertion reactions have been characterized by multinuclear NMR and single‐crystal X‐ray diffraction studies. [ABSTRACT FROM AUTHOR]

A new ligand, 3,3′-di(pyrazinamoyl)-2,2′-bipyridine, L3H2 has been prepared and is comprised of distinct binding domains capable of facilitating the formation of coordination polymers. Reaction of L3H2 with [Cu2(OAc)4(H2O)2] in the presence of Et3N·HCl affords the complex {[Cu6(L3)2(Cl)2(OAc)6]·2H2O·2MeOH}n (1) in which the [L3]2− anion binds two unique copper ions in a bis-tridentate fashion via amide and pyridyl N atoms. This bimetallic unit is linked to an equivalent unit via a pair of 1,3-acetato and μ-chloro bridges to afford a tetrameric [Cu4(L3)2Cl2(OAc)2] core. Coordination of one of the pyrazole substituents from each ligand to a third copper centre of a rigid paddlewheel [Cu2(OAc)4] unit leads to a unique 1-D polymeric structure. Magnetic studies of 1 reveal that the magnetism can be described in terms of two sets of exchange interactions; strong antiferromagnetic interactions between the two copper centres within the “paddle-wheel” (J/k = −190 K) and a combination of weaker ferro- and antiferro-magnetic interactions within the tetrameric core (J′/k = −5.7 K and J′′/k = +2.1 K). [ABSTRACT FROM AUTHOR]

In recent years, the dramatic increase in power conversion efficiency (PCE) coupled with a decrease in the total cost of third-generation solar cells has led to a significant increase in the collaborative research efforts of academic and industrial researchers. Such interdisciplinary studies have afforded novel materials, which in many cases are now ready to be brought to the marketplace. Within this framework, the field of perovskite solar cells (PSCs) is currently an important area of research due to their extraordinary light-harvesting properties. In particular, PSCs prepared via facile synthetic procedures, containing hole transport materials (HTMs) with versatile triphenylamine (TPA) structural cores, amenable to functionalization, have become a focus of intense global research activity. To optimize the efficiency of the solar cells to achieve efficiencies closer to rival silicon-based technology, TPA building blocks must exhibit favourable electrochemical, photophysical, and photochemical properties that can be chemically tuned in a rational manner. Although PSCs based on TPA building blocks exhibit attractive properties such as high-power efficiencies, a reduction in their synthetic costs coupled with higher stabilities and environmental considerations still need to be addressed. Considering the above, a detailed summary of the most promising compounds and current methodologies employed to overcome the remaining challenges in this field is provided. The objective of this review is to provide guidance to readers on exploring new avenues for the discovery of efficient TPA derivatives, to aid in the future development and advancement of TPA-based PSCs for commercial applications. [ABSTRACT FROM AUTHOR]

The targeted replacement of acetate groups in the optically inactive [MnIII3O(O2CMe)3(mpko)3](ClO4) single-molecule magnet with their naphthalene, anthracene, and pyrene fluorescent analogues has led to three new emissive SMMs with enhanced photo-luminescence properties and potential applications in the field of molecular electronics. [ABSTRACT FROM AUTHOR]

Reaction of NacNacGa with azide N3SiMe3 results in the generation of a transient imide NacNacGa(＝NSiMe3) that can cleave unactivated sp3 C–H and sp2 C–H bonds of different substrates, affording gallium amides. Pyridine, cyclohexanone, ethyl acetate, DMSO, and triethylphosphine oxide were activated in this process producing corresponding gallium amides. All new compounds were characterised by multinuclear NMR and X-ray diffraction. [ABSTRACT FROM AUTHOR]

Reaction of the Ga(I) compound NacNacGa (9) with the diazo compound N2CHSiMe3 affords the nitrilimine compound NacNacGa(N‐NCSiMe3)(CH2SiMe3) (10). Carrying out this reaction in the presence of pyridine does not lead to C−H activation on the transient alkylidene NacNacGa=CHSiMe3 but generates a metallated diazo species NacNacGa(NHN=CHSiMe3)(CN2SiMe3) (13) that further rearranges into the isonitrile compound NacNacGa(NHN=CHSiMe3)(N(NC)SiMe3) (15). Reactions of 10 with the silane H3SiPh and the borane HBcat furnished products of 1,3 addition to the nitrilimine moiety NacNacGa{N(ERn)NCSiMe3}(CH2SiMe3), whereas reaction with the diborane B2cat2 gave the product of formal nitrene insertion into the B−B bond. DFT calculations suggest that the interaction of 9 with N2CHSiMe3 proceeds through intermediate formation of an alkylidene compound that undergoes CH activation with a second molecule of N2CHSiMe3. Insertion into the B−B bond likely proceeds through an initial 1,3‐addition of the diborane, followed by boryl migration to the former nitrene center. [ABSTRACT FROM AUTHOR]

Carbon–carbon bonding forming reactions of two cyclic sulfate esters and a cyclic sulfamidate are reported, the former with lithium dianions to give substituted tetrahydrofuran derivatives with displacement of sulfate, and the latter undergoes ring-opening monosubstitution reactions with stabilised organolithiums and an organocuprate species. [Copyright &y& Elsevier]

An N‐propargyl pyrroloimidazolone with syn stereochemistry derived from L‐proline serves as a starting material for the diastereoselective synthesis (>95:5 dr) of propargyl alkynes or allenamides by direct quench of its lithiated intermediate with alkylating agents or aldehydes/ketones, respectively. Use of the epimeric anti pyrroloimidazolone starting material results in reversal of stereochemistry at the propargyl position in the products, without the need to prepare a separate substrate from D‐proline. Lithiation of the syn pyrroloimidazolone and quench with prochiral benzaldehydes without prior transmetalation gives allenamides with crystallographically verified atypical stereochemistry of the benzylic alcohol in >95:5 dr. The epimeric series of benzylic alcohols may also be obtained in >95:5 dr by employing transmetalation with chlorotitanium triisopropoxide prior to aldehyde quench. Density Functional Theory (DFT) computational studies provide a rationale for the change in benzylic alcohol stereochemistry by virtue of differing stereofacial attack in 6,5‐bicyclic (Li) or 6‐membered (Ti) transition states. [ABSTRACT FROM AUTHOR]

Examines the synthesis of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) derivatives. Condition on the preparation of tetrathionate; Outcome on the reaction of compound one with primary alkyl halides; Characterization of BEDT-TTF derivatives by elemental analysis.

The development of near‐infrared (NIR) luminescent materials has emerged as a promising research field with important applications in solid‐state lighting (SSL), night‐vision‐readable displays, and the telecommunication industry. Over the past two decades, remarkable advances in the development of light‐emitting electrochemical cells (LECs) have stunned the SSL community, which has in turn driven the quest for new classes of stable, more efficient NIR emissive molecules. In this review, an overview of the state of the art in the field of near‐infrared light‐emitting electrochemical cells (NIR‐LEC) is provided based on three families of emissive compounds developed over the past 25 years: i) transition metal complexes, ii) ionic polymers, and iii) host–guest materials. In this context, ionic and conductive emitters are particularly attractive since their emission can be tuned via molecular design, which involves varying the chemical nature and substitution pattern of their ancillary ligands. Herein, the challenges and current limitations of the latter approach are highlighted, particularly with respect to developing NIR‐LECs with high external quantum efficiencies. Finally, useful guidelines for the discovery of new, efficient emitters for tailored NIR‐LEC applications are presented, together with an outlook towards the design of new NIR‐SSL materials. [ABSTRACT FROM AUTHOR]

The preparation of a series of 4,4′,5,5′-substituted benzo-fused 1,2,5,6-tetrathiocins X2C6H2S4C6H2X2 (1a–1g) were prepared from the reaction of S2Cl2 with 1,2-C6H4X2 (X = OMe, OEt; X2 = OCH2O, OCH2CH2O, OCH2CH2CH2O, MeNC(＝O)NMe, O(CH2CH2O)4). The oxidative addition of 1a–1g to zero-valent Pd2dba3 or Pt2dba3 (dba = dibenzylideneacetone) in the presence of bis (diphenylphosphino)ethane (dppe) resulted in formation of the substituted mononuclear benzenedithiolate complexes M(L)(dppe) [L = dithiolate ligand; 2a–2g (M = Pd) and 3a–3g (M = Pt)] in 37–89% yield based on recrystallized material. Representative examples of M(L)(dppf) [dppf = bis-diphenylphosphinoferrocene; 4a, 4g (M = Pd) and 5g (M = Pt)] were prepared in a similar fashion. The structures of all derivatives were determined by X-ray diffraction, multinuclear NMR and elemental analysis. The reactivity of the two crown ether dithiolate complexes, 2g and 4g, with 1 equivalent of NaBPh4 led to isolation of the 1 : 1 complexes in which the Na+ cation is bound in the macrocyclic crown, [Na(2g)(MeOH)2][BPh4] and [Na(4g)][BPh4] whose structures were determined by X-ray diffraction. Electrochemical studies supported through DFT calculations on the crown ether derivatives revealed a series of ligand-based oxidation waves corresponding to the dithiolate ligand (and dppf for 4g and 5g) whose redox potentials were shifted by ca. +0.1 V on binding to Na+. [ABSTRACT FROM AUTHOR]

In situ oxidation of the GaI compound NacNacGa by either N2O or pyridine oxide results in the generation of a labile monomeric oxide, NacNacGa(O), which can easily cleave the C−H bonds of aliphatic and aromatic substrates featuring good donor sites. The products of this reaction are gallium organyl hydroxides. DFT calculations show that these reactions start with the formation of NacNac‐Ga(O)(L) adducts, the oxo ligand of which can easily abstract protons from nearby C−H bonds, even for sp2‐hybridized carbon centers. Aliphatic amines do not enter this reaction for kinetic reasons, presumably because of the unfavorable sterics. [ABSTRACT FROM AUTHOR]

In situ oxidation of the GaI compound NacNacGa by either N2O or pyridine oxide results in the generation of a labile monomeric oxide, NacNacGa(O), which can easily cleave the C−H bonds of aliphatic and aromatic substrates featuring good donor sites. The products of this reaction are gallium organyl hydroxides. DFT calculations show that these reactions start with the formation of NacNac‐Ga(O)(L) adducts, the oxo ligand of which can easily abstract protons from nearby C−H bonds, even for sp2‐hybridized carbon centers. Aliphatic amines do not enter this reaction for kinetic reasons, presumably because of the unfavorable sterics. [ABSTRACT FROM AUTHOR]

A tridentate ligand LH3 (C11H13N3O4) comprising o-vanillin, hydrazone and oxime donor groups has been employed to prepare a new class of di- and tetranuclear LnIII complexes. The reaction of LH3 with Ln(NO3)3·xH2O in the presence of a suitable base yields the dinuclear DyIII complex [Dy2(LH2)4(CH3OH)][NO3]2 (1) and the tetranuclear complexes [Dy4(LH)4(LH2)2(OH)2]·2H2O (2) and [Gd4(LH)4(LH2)2(OMe)2]·nH2O, (3). In these complexes, LH3 is either monodeprotonated (1) or a mixture of mono- and doubly-deprotonated ligands (2 and 3) binding lanthanide ions via Ndiazine, Ohydrazone, and Ovanillin donors, while the remaining vacant coordination sites are occupied by OMeOH (1), Ohydroxide (2) and methoxides (3). DC magnetic susceptibility studies on the isotropic tetranuclear GdIII complex (3) reveal weak antiferromagnetic exchange interactions between the LnIII ions. AC studies reveal that the dinuclear complex (1) exhibits field-induced slow relaxation of magnetization with Ueff = 43.4 K, whereas 2 is a single molecule magnet, exhibiting slow relaxation of magnetization under zero field below 18 K, which is modelled using a combination of Orbach (Ueff/kB = 26.7 K) and Raman relaxation processes. [ABSTRACT FROM AUTHOR]

The replacement of inorganic semiconductors with molecule-based compounds for applications in current-to-light conversion has led to a significant increase in interdisciplinary collaborations worldwide, affording new improved organic-light emitting diodes (OLEDs) ripe for commercial applications, as well as light-emitting electrochemical cells (LECs) that have recently started to head to the market. This review highlights the role that transition metal coordination complexes (TMCs) have played in advancing the field of molecular electronics, from early conception to the advanced development of several polypyridyl complexes currently pursued for both OLED and LEC concepts. In this context, the design and synthesis of Ir(III), Pt(II), Cu(I) and Ag(I) complexes as the emissive components of OLEDs and LECs are thoughtfully presented. We discuss how molecular design is pivotal for fine-tuning color and optimizing power efficiencies, highlighting the key roles of the metal, cyclometalate, and ancillary polypyridyl ligands. We provide insight into the strategies exploited for the development of new, improved emitters and their fabrication into OLEDs/LECs with high external quantum efficiencies and stabilities. In addition, we have surveyed the remarkable photophysical properties of third generation TMCs capable of undergoing thermally activated delayed fluorescence (TADF). Since previous reviews of TADF materials are strongly biased towards organic-based systems, this overview compliments other synopses of light emitting TADF materials. Finally, we shed light onto the conceptual challenges that still need to be overcome to advance the rational design of TMC-based TADF emitters with tunable ligands and the subsequent fabrication of OLEDs/LECs, which are tailor-made for each specific application. [ABSTRACT FROM AUTHOR]

Two homochiral M–O–M bridged mixed valence complexes [CoIII 2 CoII(mpm) 6 ]·(ClO 4) 2 (1) and [CoII 2 CoIII 2 (μ 3 -OMe) 2 (μ-mpm) 4 (NO 3) 2 (MeO) 2 ] (2) with linear and defect dicubane topologies respectively were prepared and characterized from the reaction of R - and S -mpmH (where mpmH = -methyl-2- pyridinemethanol) with an appropriate Co(II) salt. Two mixed-valence cobalt complexes, [CoIICoIII 2 (mpm) 6 ](ClO 4) 2 (1) and [CoII 2 CoIII 2 (μ 3 -OMe) 2 (μ-mpm) 4 (NO 3) 4 ] (2), where mpm is the deprotonated form of R or S α-methyl-2-pyridinemethanol, have been structurally and magnetically characterized. Both complexes crystallize in chiral space groups, where 1 is a trinuclear compound with a linear Co(III)–Co(II)–Co(III) topology and 2 is a tetranuclear cluster with a defect dicubane-type structure that has two missing vertices. In both cases the mpm− ligand bridges adjacent Co ions in a η1:η2:μ manner. The molecular geometries of the complexes reveal the Co ions are octahedral, where the greatest deviation from O h symmetry is apparent for the HS d7 Co(II) ions. The chirality of 1 and 2 were studied by circular dichroism spectroscopy where opposite Cotton effects are observed for the R- and S -enantiomers of both complexes. Magnetic susceptibility studies reveal the presence of largely quenched first order orbital angular momentum together with weak ion or intermolecular dipole exchange. [ABSTRACT FROM AUTHOR]

The synthesis of a new {Ni8} cluster bearing tetrazolate- and azido-bridging ligands, and supported by chelating α-methyl-2-pyridine-methanol (mpmH) groups, is described herein. The reported compound has a unique trapezoidal prismatic topology, resulting from an unexpected in situ click reaction between the MeCN reaction solvent and the N3− ions under mild, room-temperature conditions. Such a click chemistry approach to the preparation of 0-D compounds is relatively unexplored and represents a fruitful strategy for the synthesis of new coordination clusters and molecule-based magnetic materials. [ABSTRACT FROM AUTHOR]

Homometallic {NiII4} cubane-like clusters with a rare chiral core have been prepared via the employment of enantiomerically pure 2-(1-hydroxyethyl)pyridine (Hmpm). Comparison with the achiral cubanes derived from the related 2-pyridinemethanol (Hpym) ligand reveals drastic structural changes as a consequence of the transfer of chirality from the ligands to the whole structure. Their magnetic properties have been related to the structural features of their cubane-type cores. [ABSTRACT FROM AUTHOR]

Reaction of 2,6-dicyanopyridine with 2 equiv. of 2-(propylthio)benzenamine in the presence of lithium bis(trimethylsilyl)amide, followed by ring-closing oxidation with N-chlorosuccinimide affords the novel tridentate ligand, 2,6-bis-(1′,2′,4′-benzothiadiazinyl)pyridine (LH2). Electrochemical studies on the free ligand LH2 reveal a single well-defined 2e− oxidation process with E1/2 = +0.90 V. EPR studies of the in situ chemical oxidation of LH2 reveal the generation of a benzotriazinyl radical. Reactions of ligand LH2 with a range of divalent transition metal salts in either MeOH or MeCN in a 2 : 1 ratio at ambient temperatures afforded mononuclear complexes with general formula [M(LH2)2][X]2 (M = Mn, X = CF3SO3 (1); Fe, X = CF3SO3 (2); Fe, X = BF4 (3); Co, X = Cl (4); Ni, X = Cl (5); Zn, X = CF3SO3 (6)) and the 1 : 1 complex [Cu(LH2)(NO3)2] (7). In all cases the LH2 ligand binds in a tridentate N,N′,N′′ chelate fashion via benzothiadiazinyl NBTDA and pyridyl Npy atoms. The low spin FeII complexes (2 and 3) were implemented for NMR and UV-Vis solution studies of ligand reactivity as well as cyclic voltammetry which reveal two 1e-oxidation waves. The metal complexes 1–6 are discussed and reveal a range of geometries between octahedral and trigonal prismatic with the greatest deviation from octahedral symmetry apparent for ions with no crystal field stabilisation energy, i.e. d10 ZnII and high spin d5 MnII ions. [ABSTRACT FROM AUTHOR]

A versatile synthetic methodology to access the first family of chiral verdazyl N,N′-chelate ligands is described and exemplified by N,N′-dimethyl-, N,N′-di-isopropyl- and N,N′-diphenyl oxoverdazyls bearing two isomers of the pinene-pyridine functional group. Their physical properties were probed by X-band EPR spectroscopy, cyclic voltammetry and DFT calculations. Preliminary reactivity studies show they can act as N,N′-chelate ligands affording a chiral 1 : 1 complex (3b) with CuCl2, which was characterized by single-crystal X-ray diffraction. Variable temperature EPR studies on (3b) confirm the presence of antiferromagnetic interactions between the spins of the Cu(ii) ion and the verdazyl radical. [ABSTRACT FROM AUTHOR]

The synthesis and coordination chemistry of a new series of open chain diazine based ligands (L3aH2, L3bH2, and L3cH2) is reported. The ligands comprise a central disubstituted bipyridine moiety with two bridging alkoxide oxygen donors, together with diazine and pyridine terminal groups strategically located to coordinate three metal centres. Reactions of L3aH2 and L3bH2 with CuX2 (X− = ClO4, Cl, NO3) yield a trinuclear complex (1) and 1-D copper chains (2, 3). In these complexes the ligands bind copper ions via Nbipyridne, trans Ndiazine, Ohydrazone, and Npyridne donors while vacant sites are occupied by counter ions or solvent molecules (methanol, water, acetonitrile). Reaction of L3cH2 with MnCl2 affords a linear trinuclear Mn complex (4), where the Mn(ii) ions are connected viaμ2-Ohydrazone linkers with no N–N bridging. Reaction of L3aH2 with Fe(SO3CF3)2 yields a tetranuclear mixed valence Fe complex (5), in which both trans N–N and Ohydrazone bridging is observed. Magnetic studies reveal the presence of moderate to strong antiferromagnetic interactions in complexes 1–4 while a mix of ferromagnetic and antiferromagnetic interactions is observed in complex 5. [ABSTRACT FROM AUTHOR]

The first {Mn[sub 31]} cluster (1) has been prepared from carboxylate ions and the chelating/bridging ligand α-methyl-2-pyridine-methanol. Compound 1 possesses a unique nanosized structural topology with one of the largest energy barriers reported to-date for high-nuclearity 3d-metal clusters. Single-crystal magnetic hysteresis studies reveal the presence of hysteresis loops below 5 K, one of the highest temperatures below which molecular hysteresis has been observed for 3d-based SMMs. [ABSTRACT FROM AUTHOR]