Hetero Diels-Alder Reactions of Masked Dienes Containing Heavy Group 15 Elements.

Treatment of N,C,N-chelated organopnictogen(I) compounds ArE (1-3) (Ar=2,6-(RN=CH) C H , E/R=As/Dmp (1), Sb/tBu (2), and Bi/tBu (3), where Dmp=2,6-Me C H ) with various electron-deficient alkynes RC≡CR' (R/R'=CO Me (DMAD), R/R'=H/CO Me, or R/R'=NC F ) affords different types of heterocyclic compounds. In these reactions, 1-3 act as hidden dienes and participate in hetero-Diels-Alder (DA) reactions, a feature that has been only rarely reported for heavier pnictogen compounds. In this way, reactions of 1 furnished the set of 1-arsanaphthalenes 4-6.

Reversible C=C Bond Activation by an Intramolecularly Coordinated Antimony(I) Compound.

The reaction of N,C,N-chelated stibinidene ArSb (1) (Ar=C H -2,6-(CH=NtBu) ) with selected N-alkyl/aryl-maleimides RN(C(O)CH) (R=Me, tBu, Ph) gave the addition products with bridged bicyclic [2.2.1] structure containing an antimony atom at the bridgehead position, fused with a 6-membered benzene and a 5-membered N-alkyl/aryl-pyrrolidine ring.

Antimony(i) → Pd(ii) complexes with the (μ-Sb)Pd coordination framework.

The reaction of the antimony(i) compound ArSb (1) (where Ar = CH-2,6-(CH[double bond, length as m-dash]NtBu)) with various dimeric allyl palladium(ii) complexes [Pd(η-allyl)(μ-X)] (where allyl = CH or CHMe; X = Cl or CFCO) in a 1 : 1 stoichiometric ratio gave unique complexes with the μ-ArSb moiety bridging two palladium fragments, i.e. [{Pd(η-CH)Cl}(μ-ArSb)] (2), [{Pd(η-CHMe)Cl}(μ-ArSb)] (3) and [{Pd(η-CH)(CFCO)}(μ-ArSb)] (4).

Heavier pnictinidene gold(i) complexes.

N,C,N-Chelated pnictinidenes ArE [where E = As, Sb or Bi; Ar = 2,6-(tBuN[double bond, length as m-dash]CH)2C6H3] were used as ligands for the coordination of various gold(i) complexes. Thus, the reaction of ArE with [AuCl(Me2S)] gave complexes [AuCl(ArE)] [where E = As (1) or Sb (2)] that exhibited only limited stability in solution. By contrast, the reaction of ArBi with [AuCl(Me2S)] led to the immediate deposition of gold metal and the oxidation of the bismuth atom giving ArBiCl2.

Synthesis and non-conventional structure of square-planar Pd(ii) and Pt(ii) complexes with an N,C,N-chelated stibinidene ligand.

The N,C,N-chelated stibinidene, ArSb (Ar = C6H3-2,6-(CH[double bond, length as m-dash]NtBu)2), reacts with Pt(ii) compounds [PtCl2L2] resulting in the formation of 1 : 1 complexes, cis-[PtCl2L(ArSb)] (L = Me2S (1), dmso (2)). In contrast, attempts to synthesize similar Pd(ii) complexes failed, resulting only in the formation of elemental palladium. To increase the stability of the ArSb complexes, in particular those containing Pd(ii), the simple auxiliary ligands were replaced with C,N-chelating ones, which led to a set of four compounds of the type [RMCl(ArSb)], where R = C6H4-2-(CH2NMe2) or Fe(η5-C5H4)(η5-C5H3-2-(CH2NMe2)) and M = Pd (3, 5) or Pt (4, 6).

Synthesis of heteroboroxines with MB₂O₃ core (M = Sb, Bi, Sn)--an influence of the substitution of parent boronic acids.

The synthesis and structure of stiba-, stanna- and bismaheteroboroxines of a general formula L(E)M[(OBR)2O] supported by a N,C,N-chelating ligand L [where L = C6H3-2,6-(CH2NMe2)2, M, E = Sb, lone pair or Sn, Ph or Bi, lone pair] is reported. The target compounds are prepared by straightforward one-step reactions between oxides (LMO)2 (M = Sb or Bi) or organotin(iv) carbonate L(Ph)Sn(CO3) with four or two molar equivalents of corresponding organoboronic acid. All compounds were characterized with the help of elemental analysis, multinuclear NMR spectroscopy and on several occasions the molecular structure was determined using single-crystal X-ray diffraction analysis.