From Neutral Diarsenes to Diarsene Radical Ions and Diarsene Dications.

Diarsene [L(MeO)GaAs] (L=HC[C(Me)N(Ar)], Ar=2,6-PrCH, 4) reacts with MeOTf and NHC (NHC=1,3,4,5-tetra-methylimidazol-2-ylidene) to the diarsene [L(TfO)GaAs] (5) and the carbene-coordinated diarsene [L(MeO)GaAsAs(NHC)Ga(OMe)L] (6). The NHC-coordination results in an inversion of the redox properties of the diarsene 4, which shows only a reversible reduction event at E=-2.06 V vs Fc, whereas the carbene-coordinated diarsene 6 shows a reversible oxidation event at E=-1.

Gallaphosphene L(Cl)GaPGaL: A novel phosphinidene transfer reagent.

Gallaphosphene L(Cl)GaPGaL 1 (L=HC[C(Me)N(Ar)]; Ar=2,6-iPrCH) reacts with N-heterocyclic carbenes NHC (NHC=[CMeN(R)]C; R=Me, iPr) to NHC-coordinated phosphinidenes NHC→PGa(Cl)L (R=Me 2 a, iPr 2 b) and with isonitriles RNC (R=iPr, Cy) to 1,3-phosphaazaallenes L(Cl)GaP=C=N-R (R=iPr 3 a, Cy 3 b), respectively. Quantum chemical calculations reveal that 2 a/2 b possess two localized lone pair of electrons, whereas 3 a/3 b only show one localized lone pair as was reported for gallaphosphene 1. 2 b reacts with 2.

Syntheses and Structures of 5-Membered Heterocycles Featuring 1,2-Diphospha-1,3-Butadiene and Its Radical Anion.

LGa(P OC)cAAC 2 features a 1,2-diphospha-1,3-butadiene unit with a delocalized π-type HOMO and a π*-type LUMO according to DFT calculations. [LGa(P OC)cAAC][K(DB-18-c-6)] 3[K(DB-18-c-6] containing the 1,2-diphospha-1,3-butadiene radical anion 3⋅ was isolated from the reaction of 2 with KC and dibenzo-18-crown-6. 3 reacted with [Fc][B(C F ) ] (Fc=ferrocenium) to 2 and with TEMPO to [L Ga(P OC)cAAC][K(DB-18-c-6)] 4[K(DB-18-c-6] containing the 1,2-diphospha-1,3-butadiene anion 4 .

Metal-coordinated distibene and dibismuthene dications - isoelectronic analogues of butadiene dications.

We report the synthesis and solid-state structures of DMAP-coordinated ([L(DMAP)GaPn][OTf]; Pn = Sb 3, Bi 4) and base-free dipnictene dications ([LGaPn][BArF], Pn = Sb: = 24, 5a; 20, 5b; Bi: = 24, 6a; 20, 6b). Quantum chemical calculations indicate that the dications 5 and 6 represent isoelectronic analogues of the butadiene dication.

Modulating the frontier orbitals of L(X)Ga-substituted diphosphenes [L(X)GaP] (X = Cl, Br) and their facile oxidation to radical cations.

Modulating the electronic structures of main group element compounds is crucial to control their chemical reactivity. Herein we report on the synthesis, frontier orbital modulation, and one-electron oxidation of two L(X)Ga-substituted diphosphenes [L(X)GaP] (X = Cl 2a, Br 2b; L = HC[C(Me)N(Ar)], Ar = 2,6-PrCH). Photolysis of L(Cl)GaPCO 1 gave [L(Cl)GaP]2a, which reacted with MeSiBr with halide exchange to [L(Br)GaP]2b.

Bisstibane-distibane conversion consecutive single-electron oxidation and reduction reaction.

-Substituted naphthalene complexes (TripPn)Naph (Pn = Sb 1, Bi 2) were synthesised and their redox behaviour investigated. Oxidation of 1 with [Fc][BAr] (BAr = B(CF)) yielded [(TripSb)(TripSb)Naph][BAr] (3) containing the stibane-coordinated stibenium cation [(TripSb)(TripSb)Naph]. Subsequent reduction of 3 with KC yielded distibane (TripSb)Naph (4).

Synthesis of distibiranes and azadistibiranes by cycloaddition reactions of distibenes with diazomethanes and azides.

Cycloaddition reactions of distibene [L(MeN)GaSb] (L = HC[C(Me)NDipp]; Dipp = 2,6--PrCH)[double bond, length as m-dash] with a series of organoazides RN (R = Ph, -CFPh, 1-adamantyl (ada)) yielded azadistibiranes [L(MeN)GaSb]NR (R = Ph 1, -CFPh 2, ada 3), whereas MeSiN reacted with insertion into one Ga-Sb bond and formation of L(MeN)GaSbSb(NSiMe)Ga(NMe)L (4). Analogous compounds 5 and 6 formed after heating of 1 and 2 above 60 °C. Prolonged heating of 5 resulted in a [2 + 2] cycloaddition accompanied by elimination of LGa(NMe) and formation of tetrastibacyclobutane 7, while the reaction of 5 with a second equivalent of PhN gave heteroleptic azadistibirane 9, which isomerized at elevated temperature to distibene 10.

Synthesis and redox activity of carbene-coordinated group 13 metal radicals.

Carbenes are known to stabilize main group element compounds with unusual electronic properties. Herein, we report the synthesis of carbene-stabilized group 13 metal radicals (cAAC)MX(IPr) (M = Al, X = Br 3; M = Ga, X = Cl 4) and the corresponding cations [(cAAC)MX(IPr)][B(CF)] (M = Al, X = Br 5; M = Ga, X = Cl 6), which were characterized spectroscopically and by sc-XRD. Quantum chemical calculation gave insights into their electronic structures.

Synthesis, structure and bonding nature of heavy dipnictene radical anions.

Cyclic voltammetry (CV) studies of two L(X)Ga-substituted dipnictenes [L(RN)GaE] (E = Sb, R = Me ; E = Bi; R = Et ; L = HC[C(Me)NDipp]; Dipp = 2,6--PrCH) showed reversible reduction events. Single electron reduction of and with KC in DME in the presence of benzo-18-crown-6 (B-18-C-6) gave the corresponding dipnictenyl radical anions (DME)[K(B-18-C-6)][L(RN)GaE] (E = Sb, R = Me ; E = Bi, R = Et ). Radical anions and were characterized by EPR, UV-vis and single crystal X-ray diffraction, while quantum chemical calculations gave deeper insight into the nature of the chemical bonding.