Evgeni V. Avtomonov

Syntheses and structures of cyclopentadienyl arsenic compounds Part I: pentamethylcylopentadienyl arsenic dihalides (Cp*AsX2,X=F, Cl, Br, I)

Abstract Treatment of 1,2,3,4,5-pentamethylcyclopenta-2,4-dien-1-yl arsenic(III) dichloride (II) with two equivalents of cobaltocenium fluoride or potassium iodide affords the analogous compounds Cp*AsF2 (I) and Cp*AsI2 (IV) in 85% and 98% yield respectively. Cp*AsBr2 (III) has been synthesized by direct metathesis reaction between AsBr3 and Cp*Li in 70% yield. The new compounds have been characterized by spectroscopic methods (1H,13C,19F NMR, El-MS) and elemental analyses. The crystal structures ofI–IV were determined by X-ray diffraction methods. The AsX2-moiety inI–IV is σ-bound to the cyclopentadienyl ligand, indicating remarkable π-interaction with the diene fragment of the cyclopentadienyl ring. In addition, weak intermolecular contacts are observed inI andIV, completing the coordination sphere around the arsenic atom to pseudo-tetrahedral.

Organoplatinum compounds VII: Trimethylplatinum fluoride [(CH3)3PtF]4, the missing link in organoplatinum cluster chemistry: its synthesis, crystal structure and a comparison to the crystal structure of [(CH3)3PtOH]4

Abstract The structural chemistry of organoplatinum clusters [Me 3 PtX] 4 (X=halide) has been completed with the synthesis and X-ray investigation of [Me 3 PtF] 4 ( 1 ) and its structural comparison to the well-known hydroxide [Me 3 PtOH] 4 ( 2 ), all members of the ‘organoplatinum cubane’ family. Compound 1 , long withstanding its attempted synthesis, has been obtained by the reaction of [Me 3 PtI] 4 with XeF 2 as a mild fluorinating agent in form of colourless crystals: space group I 4 3m, Z =2, a =10.0878(7) A, R 1 =0.0242, wR 2 =0.0563. In order to discriminate 1 from its possible hydrolysis product, viz. [Me 3 PtOH] 4 ( 2 ), the latter was also synthesised according to literature procedures and re-investigated by X-ray crystallography: colourless crystals, space group I 4 3m, Z =2, a =10.1400(10) A, R 1 =0.0238, wR 2 =0.0586. NMR spectroscopic, mass spectrometric and, in part, IR data are reported for 1 and 2 . A crystalline solid obtained from equimolar chloroform solutions of both 1 and 2 did not reveal any new structural features, e.g. lattice parameters. From this mixture one might have expected a possible formation of strong hydrogen bonds of the type Me 3 Pt–F···H–O–PtMe 3 .

Carbonyl insertion into zirconium–nitrogen bonds; synthesis and X-ray structure of a carbene complex composed of [Zr(NMe2)4]2 and three Fe(CO)5 units containing Fe→Zr donor–acceptor interactions

Abstract The reaction of [Zr(NMe 2 ) 4 ] 2 with Fe(CO) 5 leads to the multicarbene complex ( 1 ) containing two zirconium and three iron atoms. The crystal structure revealed that 1 results from the insertion of five CO groups into ZrN bonds generating chelating biscarbene ligands at two iron atoms and one terminal carbene ligand at the third iron atom. Thus, a planar and a boat-configured ring are formed ( A and B ) with relatively short FeZr distances of 284 and 282 pm, respectively, indicating early–late transition-metal interactions.

Polyelement substituted cyclopentadienes and indenes — Novel ligand precursors for organotransition metal chemistry

Abstract A series of polyelement substituted cyclopentadienyl and indenyl boranes and arsanes containing Me 3 Si-, Me 3 Sn- was synthesised; (C 5 H 4 SiMe 3 )BX 2 ( 2 , X = Cl; 3 , X = Br) and (C 9 H 6 SiMe 3 )BX 2 ( 4 , X = Cl; 5 , X = Br) were obtained by Si/B exchange reaction in a low yield when X = Cl and in a moderate yield when X = Br, whereas Flu(SIMe 3 ) 2 does not react with BBr 3 at all. PhB(C 5 H 4 SiMe 3 ) 2 ( 6 ) and PhB[C 5 H 3 (SiMe 3 ) 2 ] 2 ( 7 ) were synthesised using appropriate thallium cyclopentadienides in high yields, 81% and 99% respectively. More bulky indenyl derivatives TrsB(C 9 H 7 ) 2 ( 8 , Trs = (Me 3 Si) 3 C—), PhB(C 9 H 6 SiMe 3 ) 2 ( 9 ), Ph 2 B(C 9 H 6 SiMe 3 ) ( 10 ) were prepared by metathesis reactions of lithium indenides with boron halides in high yields. A subsequent transmetallation of C 9 H 6 (SnMe 3 ) 2 with PhBCl 2 followed by addition of ZrCl 4 gave (η 5 -C 9 H 6 SnMe 2 Cl) 2 ZrCl 2 ( 11 ) in the form of one of two possible diastereomers in high yield. C 9 H 6 (SiMe 3 )SnMe 3 reacts with BCl 3 to give the appropriate bis-indenyl derivative, that was easily converted to the ansa -zirconocene complex [MeB(η 5 -C 9 H 6 ) 2 ]ZrCl 2 ( 12 ). The sterically demanding bis-indenyl ligand 8 underwent direct deprotonation by t -BuLi, affording [TrsB(η 5 -C 9 H 6 ) 2 ]ZrCl 2 ( 13 ) by in situ reaction with Me 3 SnCl and ZrCl 4 . Indenylarsanes (C 9 H 7 ) 3 As ( 14 ), t -BuAs(C 9 H 7 ) 2 ( 15 ), C 9 H 7 AsMe 2 ( 16 ) and (C 9 H 6 SiMe 3 )AsMe 2 ( 17 ) were synthesised by reactions of lithium indenides with asenic halides in good to excellent yields. All these compounds were characterized by analytical and spectroscopic data (NMR, MS). 14 and 15 exist as complex isomeric mixtures with the arsenic atom in the allylic position of the indenyl ring; the crystal structure of a meso form of 15 was determined by X-ray diffraction methods. 17 consists of two isomers with a vinylic ( 17a ) and an allylic ( 17b ) Me 3 Si substituent. Stannylation of 16 by Me 3 SnNEt 2 led exclusively to the diallylic derivative (C 9 H 6 AsMe 2 )SnMe 3 ( 18 ) in quantitative yield. The latter was readily converted to a polymeric, half-sandwich indenyl zirconocene [η 5 -(C 9 H 6 AsMe 2 )ZrCI 3 ] n ( 19 ) in high yield. Further reaction of 19 with Cp * Li resulted in the formation of a new arsano substituted bent metallocene complex [η 5 -(C 9 H 6 AsMe 2 )-η 5 -(C 5 Me 5 )]ZrCl 2 ( 20 ) in good yield.

Synthesis and crystal structure of dimeric 2,4,6-triphenylphenylbismuthdichloride

Reaction of BiCl3 with one equivalent of 2,4,6-triphenylphenyllithium in toluene results in the formation of crystalline 2,4,6-triphenyl-phenylbismuthdichloride toluene disolvate (1). The crystal structure of 1 has been determined by X-ray diffraction. In spite of the extremely bulky substituents at the bismuth atom, complex 1 is dimeric in the solid state with intramolecular Bi-Cl bond lengths of 2.530(1) A and bridging Bi-Cl of 3.074(1) A.

Syntheses and structures of cyclopentadienyl arsenic compounds II. Pentamethyl- and tetraisopropylcyclopentadienyl arsenic amido derivatives ☆ ☆☆

A series of amido derivatives of arsenic cyclopentadienyls (Cp′AsNR) n (4–6)(4: Cp′ = C 5 Me 5 , R = H, n = 4; 5 : Cp′ = C 5 Me 5 , R = Me; n = 2; 6 : Cp′ = C 5 i -Pr 4 H, R = Me, n = 2) has been synthesized by the reaction of Cp′AsX 2 ( 1–2 )( 1 : Cp′ = C 5 Me 5 , X = Cl; 2 : Cp′ = C 5 i -Pr 4 H, X = 1) with an excess of amine. The reaction proceeds via a diamido substituted intermediate which eliminates in vacuum one equivalent of free amine to give in situ imino arsanes which rapidly oligomerize to octa- or tetracyclic compounds in almost quantitative yield. In the case of bulky amines, viz t -BuNH 2 and (Me 3 Si) 2 NH, monoamido substituted arsanes Cp AsCl(NR 1 R 2 ) ( 7–8 ) ( 7 : R 1 = H, R 2 = t -Bu; 8 : R 1 = R 2 = SiMe 3 ) have been obtained by treatment of 1 with an excess of t -BuNH 2 or with one equivalent of NaN(SiMe 3 ) 2 . The fluorine substituted analogue of 8 , Cp AsF[N(SiMe 3 ) 2 ]( 9 ), has been synthesized either by reaction of one equivalent of NaN(SiMe 3 ) 2 with Cp AsF 2 ( 3 ) or by a substitution reaction between 8 and Cp 2 CoF in moderate yields. 7 reacts with strong bases, e.g. Li(Na)N(SiMe 1 ) 2 or Me 3 SnNEl 2 , giving an imino arsane as an intermediate which quickly dimerizes to diazadiarselane (Cp AsN t -Bu) 2 ( 10 ). The reaction of 1 with Ph 2 C = NNH 2 in the presence of Et 1 N as a base gives the disubstituted hydrazonato arsane Cp As(NHN = CPh 2 ) 2 ( 11 ), independent of the reagent ratio. All new compounds were characterized by spectroscopic methods ( 1 H, 13 C NMR, MS) and elemental analyses. The crystal structures of 4–8 have been determined by X-ray diffraction methods. Bonding of the arsenic fragment to the cyclopentadienyl ligand can be described as a primary σ-interaction with an additional π-interaction between the cyclopentadienyl ligand and the arsenic atom, resulting in pseudo- η 2 to η 3 -coordination. Short intramolecular AsAs contacts are found for 5 and 6 .

Synthesis of 1-cyclopropylmethylsilatrane and 1-cyclopropylmethyl-3,7,10-trimethylsilatrane. Crystal structure of 1-cyclopropylmethylsilatrane

Abstract 1-Cyclopropylmethylsilatrane ( 2a ) and 1-cyclopropylmethyl-3,7,10-trimethylsilatrane ( 2b ) have been prepared in good yields by the reaction of the corresponding 1-allylsilatranes N(CH 2 CHRO) 3 SiCH 2 CHCH 2 ( 1 ) (R  H ( a ), Me ( b )) with diazomethane in the presence of Pd(OAc) 2 as a catalyst. 1-Cyclopropylmethylsilatrane ( 2a ) has also been synthesized from the reaction of cyclopropylmethyltriethoxysilane ( 3 ) with triethanolamine. Compounds 2a, 2b and 3 have been characterized by 1 H and 13 C NMR spectroscopy and elemental analyses. An X-ray structure determination of 2a indicates the presence of an N → Si bond length of 2.149(4) A.

TIN(IV) COMPLEXES WITH O-ETHYL(N-ETHYL-N, N-DIMETHYLAMMONIOMETHYL)PHOSPHONATE

Abstract O,O-Diethyl-(N,N-dimethylaminomethyl)phosphonate undergoes ethyl migration leading to O-ethyl-(N-ethyl-N,N-dimethylammoniomethyl)phosphonate (L). Several new complexes of tin(IV) and organotin(IV) chlorides with the title ligand have been synthesized. The stoichiometry of the obtained complexes is as follows: (R3SnCl)2 · L (R=Me, Bu, Ph), R2SnCl2 · L (R=Me, Bu, Ph), RSnCl3 L (R=Me, Ph) and SnCl4 · L. All the complexes have been studied in solution by means of 1H-, 13C-, 31P- and 119Sn-NMR spectroscopy. Their solid state structures have been investigated by means of Mossbauer spectroscopy and the molecular structure of the complex (Ph3SnCl)2 · L has been determined by X-ray crystallography. The ligand behaves as a bidentate ligand, bridging two pentacoordinate trigonal bipyramidal organotin moieties through an O–P–O fragment. The spectroscopic data for R2SnCl2 · L, RSnCl3 · L and SnCl4 · L suggest hexacoordinate structures with an octahedral tin environment, the complexes probably being polymeric according to the bridging ligand behavior.

1-Allylgermatrane. Synthesis, Structure and Reaction with Diazomethane

Reaction of allyltribromogermane (2), readily available from dibromo(1,4-dioxane)germanium(II) (1) and allylbromide, with tris(2-tributylstannoxyethyl)-amine (4) gives 1-allylgermatrane (3) in almost quantitative yield. 3 crystallizes from n-pentane as a colourless crystalline solid which was characterized by 1H and 13C NMR spectroscopy and by an X-ray crystal structure study. The “atrane” skeleton shows a strong conformational disorder; the Ge-N distance of 2.208(3) Å suggests the presence of a coordinative Ge-N bond. Treatment of 1-allylgermatrane (3) with CH2N2 in the presence of catalytic amounts of Pd(OAc)2 affords 1-cyclopropylmethylgermatrane (5) in high yield

Zirconium Reagents for Organometallic Synthesis. Crystal Structures of ZrCl4 ·2Et2O and (Et2N)ZrCl3·Et2O

Reaction of 3 equivalents of ZrCl4 · 2Et2O (1) with 1 equivalent of (Et2N4Zr in diethyl ether readily affords crystalline (Et2N)ZrCl3 · 2Et2O (2) in almost quantitative yield. The product was characterised by elemental analysis and by 1H. 13 C NMR, and MS techniques. The reactivity of this reagent towards C-H acidic compounds has been studied using cyclopentadiene as a C-H acid. The crystal structures of both 1 and 2 have been determined by X-ray diffractometry. The coordination polyhedra reveal a nearly perfect octahedral geometry with a trans Et2O ligation for 1 and a cis one for 2.