Konstantin A. Rufanov

Synthesis and structure of a series of new haloaryl imido complexes of molybdenum

Abstract The synthesis of a series of mono- and bis-haloarylimido molybdenum(VI) complexes is described. Two methods of introducing the electron poor imido functionality are employed, first the condensation of substituted anilines with Na2MoO4 in the presence of Me3SiCl/NEt3, secondly the sulfinyl amine metathesis with [Mo(O)2Cl2(dme)] (1). The latter method works even in cases, when the first one does not work. Crystal structures of three complexes [Mo(NC6F5)(O)Cl2(dme)] (2a), [Mo(N-2,6-Cl2C6H3)2Cl2(dme)] (3b) and [Mo(N-2,4,6-Br3C6H2)2Cl2(dme)] (4) are reported. The unusually small MoNC(Ar) angle of 149.1(5)° has been found in the structure of 4.

Hetero-ansa-metallocenes: I. Synthesis of the novel [1]-borylidene-bridged ansa-zirconecene dichloride

Abstract The first ansa -[1]-zirconecene dichloride with the boron bridge atom, [( μ −PhB)( η 5 −C 5 H 4 ) 2 ]ZrCl 2 (5) is synthesised via subsequent transmetallation of C 5 H 4 (SnMe 3 ) 2 by PhBCl 2 and ZrCl 4 . The unstable corresponding ligand — PhB(C 5 H 5 ) 2 (1) — was synthesised and isolated in the form of pyridine (1:1) (2) and DABCO (2:1 (3) adducts.

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 molecular structures of the first phosphoranylidene complexes of rare earth metals

Metallation of the donor-functionalised ylide ligand Ph3PCH–(o-CH3OC6H4) with homoleptic alkyl and aryl complexes of yttrium and lutetium furnished unprecedented phosphoranylidene complexes, featuring a central μ2-M2C2 core.

Unusual reactivity of tritylcyclopentadienylmetal derivatives. Molecular structure of Ph3CC5H4SnMe3 and Ph3CC5H4TiCl3

The preparative synthetic routes to tritylcyclopentadienyl metal derivatives of sodium, tin and titanium have been studied. Molecular structures of Ph3CC5H4SnMe3 (3) and Ph3CC5H4TiCl3 (4) have been defined. The ClPh agostic interaction in the structure of 4 provides an unprecedented low reactivity of 4 to nucleophiles of different natures.

Synthesis of highly crowded cyclopentadienes via reactions of Cp2Ni and CpSn(CH3)3 with triarylmethylhalogenides. Molecular structure of 1-(CH3)3Si(3-Ph3C)C5H4

Abstract Triphenylmethylcyclopentadiene Ph 3 CC 5 H 5 ( 1 ) and 2-[tris-(2′-methoxyphenyl)methyl]cyclopentadiene 2-((2′-CH 3 OC 6 H 4 ) 3 C) C 5 H 5 ( 2 ) have been prepared in high yields via reactions of the corresponding triarylmethyl-halogenides with Cp 2 Ni (and CpSn(CH 3 ) 3 in the case of 1 ). It is shown that 3-tritylsubstituted 6,6-dimethylfulvene formed exclusively in the reaction between the lithium salt of 1 and acetone. Cyclopentadiene 2 exists only as the 2-triarylmethylsubstituted isomer in a mixture of two enantiomeric forms caused by the C 3v -asymmetry type in the relative orientation of the aryl groups. Cyclopentadiene 1-Si(CH 3 ) 3 -(3-Ph 3 C)-C 5 H 4 was obtained by reaction of the sodium salt of 1 with (CH 3 ) 3 SiCl; it crystallizes from hexane in the monoclinic space group P2 1 /c with cell dimensions a = 11.635(5), b = 12.400(7), c = 15.531(7)A, V = 2240.09(9)A 3 and Z = 4; the Si atom is in the allylic position with d(C Cp Si) = 1.891(8)A,Si C(3) C(2) = 109.7(6)°,Si C(3) C(4) = 110.3(6)°,C(2) C(3) C(4) = 100.2(7)°.

First transition-metal complexes of SP(NHBut)3

The first transition-metal (Rh(I), Mo(VI), Ni(II)) complexes of S[double bond, length as m-dash]P(NHBu(t))(3) have been synthesized via metathetical reactions of mono-lithiated and [Rh(CO)(2)Cl](2), (Bu(t)N)(2)MoCl(2)(dme) and NiBr(2)(dme). Surprisingly in the molecular structure of the Ni(II)-complex both hard-soft (N,S) and hard-hard (N,N[prime or minute]) chelation modes of are realized.

Synthesis of the novel bifunctional ligand, dicyclopentadienylsulfide (C5H5)2S, and its dilithium salt

Abstract The dicyclopentadienylsulfide ligand (C5H5)2S (1) was synthesized via reaction of CpTl with SCl2. The dilithium salt Li2[(C5H4S] (2) was obtained by the reaction of 1 with nBuLi and was characterized spectroscopically.

Dichloro(1,2-dimethoxyethane)bis(tosylimido)molybdenum(VI), a versatile nitrene transfer reagent.

In the title compound, [Mo(C7H7NO2S)2Cl2(C4H10O2)], the Mo-Cl bond lengths are 2.3730 (8) and 2.3842 (8) A, the former being the shortest within the series of analogous structurally characterized bis(imido) Mo complexes. This fact clearly explains the very strong Lewis acidity of the metal centre in this complex and, as a result, its synthetic versatility as a nitrene transfer reagent towards different phosphanes and strained cycloolefins.

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.