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Variation of a single ligand in the W(ii) alkyne complexes of bis(diphenylphosphino)acetylene leads to W(ii)/W(iii) redox potentials spanning a window of 850 mV. The corresponding dinuclear complexes with PdCl2 show differing catalytic activity.

A new synthetic route to 1H-1,2,3-triazole-4,5-dithiols (tazdtH2) as ligands for the coordination of NiII, PdII, PtII and CoIII via the dithiolate unit is presented. Different N-protective groups were introduced with the corresponding azide via a click-like copper-catalyzed azide-alkyne [3 + 2] cycloaddition (CuAAC) and fully characterized by NMR spectroscopy. Possible isomers were isolated and an alternative synthetic route was investigated and discussed. After removal of the benzyl protective groups on sulfur by in situ-generated sodium naphthalide, complexes at the [(dppe)M] (M = Ni, Pd, Pt), [(PPh3)2Pt] and [(η5-C5H5)Co] moieties were prepared and structurally characterized by XRD analysis. In this process, the by-products 11 and 12 as monothiolate derivatives were isolated and structurally characterized as well. With regioselective coordination via the dithiolate unit, the electronic influence of different metals or protective groups at N was investigated and compared spectroscopically by means of UV/Vis spectroscopy and cyclic voltammetry. Complex [(η5-C5H5)Co(5c)] (10), is subject to a dimerization equilibrium, which was investigated by temperature-dependent NMR and UV/Vis spectroscopy (solution and solid-state). The thermodynamic parameters of the monomer/dimer equilibrium were derived.

1,2,3-Triazole dithiol derivatives, which are straightforwardly accessible by 1,3-dipolar addition of azides with sulfide substituted alkynes, show dithiolene-type coordination behaviour.

The cycloaddition of aldehydes to the singlet biradical [P(μ-NTer)]2 is demonstrated experimentally. High-level ab initio calculations reveal a minimal electronic activation barrier.

Reaction of [(μ-NR)P˙]2 with CSCl2 and Mg gives a deep blue, highly labile cyclic thioketone with singlet biradical character. It can be converted to a housane-type isomer by light and to bicyclic cage compounds by addition of CS2 and benzaldehyde.

The synthesis and reactivity of sterically demanding phosphaarsanes TerR1P-AsR2 (3) is described. These species were selectively synthesized via metathesis reactions of Ter-stabilized [Ter = 2,6-bis(2,4,6-trimethylphenyl)phenyl] potassium phosphides TerR1PK (1) with the N-heterocyclic chloroarsane ClAs{N(tBu)CH2}2 (2). Conversion of the n-butyl-substituted phosphaarsane 3c with the reactive heterocumulene CS2 leads to an insertion into the P-As bond, yielding the phosphane arsanyldithiocarboxylate TerR1P-C(S)S-AsR2 (4c) as a new structural motif. Because full conversion of 3c with CS2 requires long reaction times, an alternative synthetic route is reported herein, involving the conversion of 2 with phosphane dithiocarboxylates TerR1-C(S)SK (5), enabling synthetic access to a wider range of phosphane arsanyldithiocarboxylates. These interpnictogen dithiocarboxylates show an interesting bonding situation with a significantly elongated As-S bond due to negative hyperconjugation within the molecule. All products along the reaction path were fully characterized.

Sterically demanding secondary potassium phosphides (4) were synthesized and investigated. Reaction with halophosphanes (5) yields diphosphanes (6), whereas reaction with CS2 yields phosphanyl dithioformates (10). These can be further converted to the corresponding phosphanyl esters of dithioformic acid R2P-C(S)S-PR2 (8). One of these thioesters (8) was found to undergo a migration reaction, resulting in the formation of a phosphanylthioketone with an additional phosphanylthiolate group (9), which was used as a chiral ligand in gold coordination chemistry. The phosphanyl migration reaction was investigated by spectroscopic and theoretical methods, revealing a first-order reaction via a cyclic transition state. All species mentioned were fully characterized.

Functionalized imidazolium cations were combined with the hexacyanidosilicate anion, [Si(CN)6]2���, by salt metathesis reactions with K2[Si(CN)6], yielding novel ionic compounds of the general formula [R���Ph(nBu)Im]2[Si(CN)6] {R = 2-Me (1), 4-Me (2), 2,4,6-Me = Mes (3), 2-MeO (4), 2,4-F (5), 4-Br (6); Im = imidazolium}. All synthesized imidazolium hexacyanidosilicates decompose upon thermal treatment above 95 ��C (96 ��� 164 ��C). Furthermore, the hexa-borane-adduct [Mes(nBu)Im]2{Si[(CN)B(C6F5)3]6}��6CH2Cl2 (7), which is thermally stable up to 215 ��C, was obtained from the reaction of 3 with Lewis acidic B(C6F5)3. In CH3CN solution, decomposition of the hexaadduct to the Lewis-acid-base adduct CH3CN���B(C6F5)3 and [(C6F5)3B��(��-CN)��B(C6F5)3]��� was observed. All synthesized compounds were isolated in good yields and were completely characterized including single crystal structure elucidations. �� 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

The reaction of TMP-NH2 [TMP = m,m-(CF3)2-C6H3] with 2 equiv of n-BuLi led to the in situ formation of Li2[N-TMP], which, after the addition of BiCl3, formed a [Cl-Bi(μ3-N-TMP)]4-type heterocubane in up to 30% yield. Transmetalation reactions, thought of as alternatives, starting from the analogous tin–nitrogen heterocubane [Sn(μ3-N-TMP)]4 and BiCl3 resulted in the isolation of a complex reaction mixture from which different Bi–N and Bi–Sn–N cage compounds could be isolated. The structures of all cage compounds that contain bismuth are discussed, and the thermodynamics of the formation of [Cl-Bi(μ3-N-TMP)]4 are highlighted. In an attempt to isolate Li2[N-TMP], generated in situ from TMP-NH2 and 2 equiv of n-BuLi, it was possible to isolate a lithium salt with a negatively charged lithium cluster of the type [Li9(N-TMP)5F]2– with an unusual Li9N5F skeleton.

The trapping of classical hydrogen pseudohalides (HX, X = pseudohalogen = CN, N3, NCO, NCS, and PCO) utilizing a phosphorus-centered cyclic biradicaloid, [P(μ-NTer)]2, is reported. These formal Brønsted acids were generated in situ as gases and passed over the trapping reagent, the biradicaloid [P(μ-NTer)]2, leading to the formation of the addition product [HP(μ-NTer)2PX] (successful for X = CN, N3, and NCO). In addition to this direct addition reaction, a two-step procedure was also applied because we failed in isolating HPCO and HNCS addition products. This two-step process comprises the generation and isolation of the highly reactive [HP(μ-NTer)2PX]+ cation as a [B(C6F5)4]- salt, followed by salt metathesis with salts such as [cat]X (cat = PPh4, n-Bu3NMe), which also gives the desired [HP(μ-NTer)2PX] product, with the exception of the reaction with the PCO- salt. In this case, proton migration was observed, finally affording the formation of a [3.1.1]-hetero-propellane-type cage compound, an OC(H)P isomer of a HPCO adduct. All discussed species were fully characterized.

The photo-isomerization of an isolable five-membered singlet biradical based on C, N, and P ([TerNP]2CNDmp, 2a) selectively afforded a closed-shell housane-type isomer (3a) by forming a transannular P-P bond. In the dark, the housane-type species re-isomerized to the biradical, resulting in a fully reversible overall process. In the present study, the influence of tBuNC on the thermal reverse reaction was investigated: the isonitrile acted as a catalyst, thus allowing control over the thermal reaction rate. Moreover, tBuNC also reacted with the biradical to form an adduct species ([TerNP]2CNDmp·CNtBu, 4a), which can be regarded as the resting state of the system. The reactive species 2a and 3a could be re-generated in situ by irradiation with red light. The results of this study extend our understanding of this new class of molecular switches.

Formal addition reactions between the open-shell singlet biradical [P(μ-NTer)]

The preparative assembly and electrochemical and photophysical behavior of di- and tetranuclear complexes held together by minimalist ditopic ligands based on 1-phosphine- or 1-pyridine-substituted prop-1-ynes are presented.

The reactivity of the secondary phosphide KP(iPr)Ter (1) (Ter = 2,6-bis-(2,4,6-trimethylphenyl)phenyl) toward small molecules is reported. Phosphide 1 displays distinct nucleophilic character and reacts selectively with chalcogens (S8, Sex), heteroallenes (CO2, nPrNCS), and an acyl chloride (AdCOCl) to give the corresponding dichalcogenophosphinates (2a, 3), phosphanyl formate (5), thiocarbamoylphosphane (6a), or acylphosphane (7a), respectively. Furthermore the follow-up chemistry of these products was investigated. 2a was converted to a PSPS ligand (2b) which forms a Au(I) complex (2c) with (Me2S)AuCl. Likewise, a gold complex of 7a was prepared. All species were isolated and fully characterized.

Recently, alkyne complexes with terminal thiolate/amide substitution have been shown to act as S,N-chelate ligands in dinuclear complexes. In this study, the detailed synthesis and reactivity of W(...

A facile synthesis and full characterization of a series of [Ag(arene)3][B(C6F5)4] salts (arene = C6H6, MeC6H5, EtC6H5, i-PrC6H5, n-PrC6H5, 1,2-Me2C6H4, 1,3-Me2C6H4, 1,4-Me2C6H4, 1,2,3-Me3C6H3, 1,2...

The synthesis of Bbp stabilized biradicals of the type [E(μ-NBbp)]2 (E = P, As) (Bbp = 2,6-bis[bis(trimethylsilyl)methyl]phenyl) was investigated. Contrary to the established synthetic protocol for terphenyl substituted biradicals [E(μ-NTer)]2 by reduction of [ClE(μ-NTer)]2, the analogous Bbp substituted precursor [ClE(μ-NBbp)]2 could only be obtained in low yields. For this reason, a new synthesis had to be found to generate [E(μ-NBbp)]2. Instead of using cyclic [ClE(μ-NBbp)]2 we prepared the acyclic Bbp–N(ECl2)2 species starting from Bbp–NH2 and ECl3 and studied the reduction with magnesium chips, which led to the formation of the desired biradicals [E(μ-NBbp)]2. All species along the reaction path were fully characterized.

Various tin(ii) compounds such as Mes*2Sn (Mes* = 2,4,6-tri-tert-butylphenyl), Sn[N(SiMe3)2]2 and TerSnCl (Ter = 2,6-bis(2,4,6-trimethylphenyl)phenyl) could be readily oxidised by organic azides to release N2, forming nitrogen-tin compounds. Depending on the used Sn(ii) compound, the reactions with two equivalents of azide led to the formation of tetrazastannoles (R2N4SnR'2) or cyclo-distannadiazanes [R2Sn(μ-NR')]2. The reactivity was independent of the electronic situation of the organic azide. Additionally, Mes*2Sn formed an amido-azido compound of the type R(R')Sn(N(SiMe3)2)N3 in the presence of Me3SiN3. Presumably, the corresponding tetrazastannole was formed in the first step followed by a ring opening reaction. The same holds true for the reaction of Sn[N(SiMe3)2]2 with Me3SiN3 while TerSnCl showed no reaction in the presence of Me3SiN3, even after prolonged heating.

The reaction of TerN(SiMe3)BiCl2 (1) (Ter = 2,6-bis(2,4,6-trimethylphenyl)phenyl) with Lewis acids such as GaCl3 and Ag[OTf] (OTf = OSO2CF3) was studied. While the reaction of 1 with GaCl3 led to d...

The terminal phosphine groups at the tungsten bisphosphine alkyne complex [Tp*W(CO)(I)(η2-C,C′-Ph2PC2PPh2)] (2) {Tp* = hydridotris(3,4,5-trimethylpyrazolyl)borate} were selectively oxidized by common methods to form the alkyne complexes 2EE (E = O, S) with either two phosphine oxide or two phosphine sulfide substituents. The respective mono-oxidized analogues 2E (E = O, S) were obtained by subjecting the already oxidized intermediates [Tp*W(CO)(I)(η2-C,C′-Ph2P(E)C2H)] 1E (E = O, S) to a late-stage phosphine introduction at the complex template. These modulations of the peripheral alkyne moiety have a clear impact on the redox potential of the metal-based oxidation altering the W(II/III) potential by +0.1 V on average per oxidized phosphine. In contrast to the comparable redox behavior of 2O and 2S, the coordination behavior of these complex ligands differs substantially. XRD studies show that complex 2 and the sulfide 2S act either as a P,P’- or P,S-chelate ligand leading to the dinuclear complexes [(2)Pd...

The chemistry of arsenic cyanides has been investigated and is found to be completely different to the chemistry of the heavier analogs antimony and bismuth as well as phosphorus. The reaction of As(CN)3 with cyanide salts resulted in the formation of an unknown cyanido arsazolide heterocycle, which represents a structure isomer of the desired [As(CN)4 ]- . The structure, bonding, and formation of this unusual heterocycle is discussed featuring an arsenic mediated C-C coupling of cyanides. [AsC4 N4 ]- salts with different counterions such as [PPh4 ]+ , [PPN]+ =[Ph3 P-N-PPh3 ]+ , Ag+ , and [BMIm]+ are reported with [BMIm][AsC4 N4 ] being a low-temperature ionic liquid (Tm =-62 °C).

The synthesis of N-trimethylstannylamines of the type RN(SnMe3)H (stannylated anilines) with the sterically encumbered substituents R such as Ter [terphenyl, 2,6-bis(2,4,6-trimethylphenyl)-phenyl], Ar* [2,6-bis(diphenylmethyl)-4-methylphenyl], and Mes* (supermesityl, 2,4,6-tri-tert-butylphenyl) is described. These stannylated anilines were treated with BiCl3 leading to the formation of RN(H)BiCl2 (for R = Ter), (RNH)3Bi (for R = Mes*), and RN(BiCl2)2 (for R = Ar*). The synthesis and structure of the starting material RN(SnMe3)H and the new aminobismuthanes are reported.

We present the synthesis and coordination chemistry of a series of WII alkyne complexes with symmetric and asymmetric acetylene diphosphines. Chelate-like P,P'-coordination of PtCl2 cause a drastic potential change of the W centered oxidation proving intermetallic cooperativity. The choice of peripheric P-substituents has a measurable influence on the potential itself as well on the respective potential change upon coordination. The enlarged deviation of the diphosphino alkyne from linearity in the dinuclear complexes unlock alkyne rotation making different isomers accessible.

When [PPN]SCN (1; PPN = [Ph3P–N–PPh3]) is treated with Me3Si–SCN in methanol, [PPN][H(NCS)2] (2), a hydrogen diisothiocyanate salt bearing the [H(NCS)2]− anion, was generated, isolated, and fully c...

Dalton Transactions, 48 (28), ISSN:1477-9226, ISSN:1477-9234

Herein, we report on the synthesis, isolation and comprehensive characterization (M.p., ATR-IR/Raman, elemental analysis, 14N NMR) of tetraazido zincate anions [Zn(N3)4]2− in a series of [Ph4P]+ and [PNP]+ (PNP = bis(triphenylphosphine)iminium) salts. The phase polymorphism in [Ph4P]2[Zn(N3)4] was investigated by temperature dependent Raman, powder and single crystal X-ray diffraction experiments, which indicate the occurrence of five room-temperature stable, and one common high-temperature phase, besides two polymorphs of the acetonitrile solvate [Ph4P]2[Zn(N3)4] · MeCN. Moreover, the synthesis of zinc azide solvates Zn(N3)2 · n solvent (solvent = DMSO, n = 1, 3/2, 3; MeCN, n = 2/3) is presented for the first time. Single crystal X-ray structures of all new compounds were determined. For a better understanding of structure and bonding in E(N3)2, [E(N3)3]− and [E(N3)4]2− (E = Zn, Cd, Hg), theoretical calculations at the M06-2X/aug-cc-pVDZ level were carried out.

The reaction of in situ generated E(CN)3 (E = Sb, Bi) with different amounts of [Ph4P]CN and [PPN]CN ([PPN]+ = [Ph3P–N–PPh3]+) was studied, affording salts bearing the novel ions [E(CN)5]2–, [Bi2(CN)11]5–, and [Bi(CN)6]3–. The valence lone pair of electrons on the central atom of antimony and bismuth(III) compounds can be either sterically active in an unsymmetric fashion (three shorter bonds + x longer bonds) or symmetric (with rather long averaged bonds). In the presence of weakly coordinating cations (e.g., [Ph4P]+ and [PPN]+), the solid-state structures of salts with [E(CN)5]2– anions contain well-separated cations and monomeric anions, which display a sterically active lone pair and a monomeric square-based pyramidal (pseudo-octahedral) structure. The [Bi(CN)5·MeCN]2– acetonitrile adduct ion exhibits a strongly distorted octahedral structure, which is better understood as a [5 + 1] coordination. The intriguing [Ph4P]6[Bi2(CN)11]CN salt consists of separated cations and anions as well as well-separate...

The heavy pnictogen tricyanides, E(CN)3 (E = Sb, Bi), were synthesized from EF3 and Me3SiCN in ionic liquids, e.g. 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIm][OTf]), which prevents the oligomerization of the molecular E(CN)3 species by formation of [BMIm][E(CN)3(OTf)] salts in solution. Recrystalli¬sation of [BMIm][E(CN)3(OTf)] from tetrahydrofuran (thf) led to the isolation and full characterization of the molecular species E(CN)32thf.

Reduction of silylated 1,3-dichloro-1,3-diphospha-2,4-diazane, [ClP(µ-NHyp)]2 [Hyp = Si(SiMe3)3], with activated magnesium in dimethoxyethane allowed the isolation and full characterization of the first stable silylated biradicaloid, [P(µ-NHyp)]2. The oxidation of [P(µ-NHyp)]2 with selenium and sulfur was studied. Activation of molecules bearing double bonds was achieved in the reaction with acetone and carbon disulfide, yielding heteroatom cage compounds.

The synthesis and some key reactions of the cyclotetraphosphane [ClP(μ-PMes*)]2 (2, Mes* = 2,4,6-tri-tert-butylphenyl) with Lewis acids and reducing agents are discussed. All products were fully ch...

A complete series of terphenyl-substituted 1,3-dichloro-1,3-dipnicta-2,4-diphosphanes {[ClE(μ-P-Ter)]2, where E = P, As, Sb, or Bi and Ter = 2,6-bis(2,4,6-trimethylphenyl)phenyl} was prepared and fully characterized. While the heavy derivatives with E = Sb or Bi can be accessed via conversion of silylated phosphanes with amino-dichloropnictanes and subsequent elimination of TerNH2, the lighter congeners could be prepared only by a metathesis reaction of [ClBi(μ-P-Ter)]2 with PCl3 and AsCl3. Spectroscopic and structural data indicate the existence of cis and trans isomers of [ClP(μ-P-Ter)]2 in contrast to all heavier derivatives, for which only the trans isomer was obtained.

The reactions of [BF4]– salts with Me3SiCN were studied at different temperatures and in the presence of several different Lewis acids, which led to the generation of the well-known [BF4–n(CN)n]– (n = 1–4) salts. Depending on the catalyst and the reaction conditions, the whole series of [BF4–n(CN)n]– salts is now accessible under ambient conditions, and long preparation times and the excessive production of waste materials can be avoided. The best results were obtained when the F–/CN– substitution reactions were performed in ionic liquids.

The reaction of lithium N-trimethylsilyl-amides of the type RN(SiMe3)Li with bismuth(iii) chloride yielded mono-, di- or triaminobismuthanes depending on the sterical demand of the anilide ligand R and the used stoichiometry. For the bulky Mes* substituent the reaction with BiCl3 resulted in the formation of a C-C coupling product as the main product besides a small amount of the expected Mes*N(SiMe3)BiCl2.