From Sn(II) to Sn(IV): Enhancing Lewis Acidity Via Oxidation.

We demonstrate the increased Lewis acidity on going from Sn(II) to Sn(IV) by oxidizing TpSnOTf (OTf = SOCF) to TpSnF(OTf). Replacement of the fluoride ion in TpSnF(OTf) by a triflate, resulting in TpSn(OTf) further enhances the Lewis acidity at tin. Sn NMR spectroscopy, modified Gutmann-Beckett test, computational analysis, and catalytic phosphine oxide deoxygenation support the claims.

Chemistry of group 5 metallaboranes with heterocyclic thiol ligands: a combined experimental and theoretical study.

Thermolysis of [(Cp*Nb)(BH)], 1b (Cp* = η-CMe), with 2-mercaptobenzothiazole, CHNSCSH (MBT), and 2-mercaptobenzoxazole, CHNOCSH (MBO), yielded hydrogen substituted compounds 2 and 3 with a general formula [(Cp*Nb)(BH)(BHL)] (2: L = CHNSCS and 3: L = CHNOCS). A similar reaction of 1b with PhSe yielded the monosubstituted derivative [(Cp*Nb)(BH){BH(PhSe)}], 4. All further efforts towards persubstitution of 1b under various drastic conditions were unfruitful.

Triple-Decker Sandwich Complexes of Tungsten with Planar and Puckered Middle Decks.

A triple-decker complex of tungsten, [(Cp*W){μ-η:η-BHCo(CO)}(H)] (; Cp* = η-CMe), with a planar middle deck has been isolated by thermolysis of an in situ formed intermediate from the reaction of Cp*WCl and LiBH with Co(CO). In addition, we have also isolated another triple-decker complex, [(Cp*W){μ-η:η-BHFe(CO)}(H)] (), having a puckered central ring, from a similar reaction with Fe(CO). Clusters and are unprecedented examples of a triple-decker complex having a 24-valence electron with bridging hydrogen atoms.

"Triple-Decker Sandwich" Containing Planar {BEPd} Ring (E = S or Se).

In an effort to generate triple-decker complexes comprising a {PdCl}moiety in the middle deck, we have explored the reactivity of [(Cp*M){μ-BHE}], - (: M = Co, E = S; : M = Co, E = Se; : M = Rh, E = Se; and : M = Ir, E = Se; Cp* = η-CMe), with [PdCl(COD)] (COD = 1,5-cyclooctadiene). The reactions led to the formation of a series of trinuclear heterometallic triple-decker complexes, [(Cp*M){μ-BHEPd(Cl)}], - (: M = Co, E = S; : M = Co, E = Se; : M = Rh, E = Se; and : M = Ir, E = Se). Formation of the complexes - occurred almost instinctively as a single product with the elimination of the COD ligand.

Chalcogen Stabilized bis-Hydridoborate Complexes of Cobalt: Analogues of Tetracyclo[4.3.0.0 .0 ]nonane.

Treatment of Li[BH ER] (E=Se or Te, R=Ph; E=S, R=CH Ph) with [Cp*CoCl] led to the formation of hydridoborate complexes, [{CoCp*Ph}{Cp*Co}{μ-EPh}{μ-κ -E,H-EBH }], 1a and 1 b (1 a: E=Se; 1 b: E=Te) and a bis-hydridoborate species [Cp*Co{μ-κ -Se,H-SeBH }] , 2. All the complexes, 1 a, 1 b and 2 are stabilized by β-agostic type interaction in which 1 b represents a novel bimetallic borate complex with a rare B-Te bond. QTAIM analysis furnished direct proof for the existence of a shared and dative B-chalcogen and Co-chalcogen interactions, respectively.

Polyhedral [MB] Metallaborane Clusters and Derivatives: An Overview of Their Structural Features and Chemical Bonding.

A large number of metallaborane clusters and their derivatives with various structural arrangements are known. Among them, MB clusters and derivatives constitute a significant class. Transition metals present in these species span from group 4 to group 7.

Diborane(6) and Its Analogues Stabilized by Mono-, Bi-, and Trinuclear Group 7 Templates: Combined Experimental and Theoretical Studies.

Irradiation of [Re(CO)] in the presence of BH·thf resulted in the formation of several rhenium diborane(6) species, for example, [{(OC)Re}{Re(CO)}(μ-η:η:η-BH)(μ-H)], ; [{(OC)Re}{Re(CO)}(μ-η:η:η-BH)(μ-H)], ; and [{(OC)Re}(μ-η:η-BH)], , comprising diverse coordination modes of the [BH] ligand. Compound contains a tris(bidentate) [BH] unit, whereas consists of an unsymmetrically bound [μ-η:η:η-BH] ligand. In contrast, the irradiation of [Mn(CO)] with BH·thf yielded only the Mn analogue of , [{(OC)Mn}{Mn(CO)}(μ-η:η:η-BH)(μ-H)], .

Metal-Rich Oxametallaboranes of Group 5 Metals: Synthesis and Structure of a Face-Fused μ-Boride Cluster.

Aerobic oxidation of metallaborane compounds is an unexplored field apart from the few reports on accidental oxidation leading to oxametallaboranes. An effective method for the synthesis of group 5 oxametallaboranes has been developed by the oxidation of [(Cp*M)(BH)] (M = Ta/Nb) (Cp* = η-CMe). The reaction of [(Cp*M)(BH)] (M = Ta/Nb) with O gas at room temperature yielded oxametallaboranes [(Cp*M)(BHO)] (for 1, M = Nb; for 2, M = Ta).

New Trinuclear Complexes of Group 6, 8, and 9 Metals with a Triply Bridging Borylene Ligand.

Trinuclear complexes of group 6, 8, and 9 transition metals with a (μ3 -BH) ligand [(μ3 -BH)(Cp*Rh)2 (μ-CO)M'(CO)5 ], 3 and 4 (3: M'=Mo; 4: M'=W) and 5-8, [(Cp*Ru)3 (μ3 -CO)2 (μ3 -BH)(μ3 -E)(μ-H){M'(CO)3 }] (5: M'=Cr, E=CO; 6: M'=Mo, E=CO; 7: M'=Mo, E=BH; 8: M'=W, E=CO), have been synthesized from the reaction between nido-[(Cp*M)2 B3 H7 ] (nido-1: M=Rh; nido-2: M=RuH, Cp*=η(5) -C5 Me5 ) and [M'(CO)5 ⋅thf] (M'=Mo and W). Compounds 3 and 4 are isoelectronic and isostructural with [(μ3 -BH)(Cp*Co)2 (μ-CO)M'(CO)5 ], (M'=Cr, Mo and W) and [(μ3 -BH)(Cp*Co)2 (μ-CO)(μ-H)2 M''H(CO)3 ], (M''=Mn and Re). All compounds are composed of a bridging borylene ligand (B-H) that is effectively stabilized by a trinuclear framework.

Hypoelectronic 8-11-Vertex Irida- and Rhodaboranes.

A series of novel isocloso-diiridaboranes [(Cp*Ir)2B6H6], 1, 2; [1,7-(Cp*Ir)2B8H8], 4; [1,4-(Cp*Ir)2B8H8], 5; [(Cp*Ir)2B9H9], 8; isonido-[(Cp*Ir)2B7H7], 3; and 10-vertex cluster [5,7-(Cp*Ir)2B8H12], 6 (Cp* = η(5)-C5Me5) have been isolated and structurally characterized from the pyrolysis of [Cp*IrCl2]2 and BH3·thf. On the other hand, the corresponding rhodium system afforded 10- and 11-vertices clusters [5-(Cp*Rh)B9H13)], 7, and [(Cp*Rh)2B9H9], 9, respectively. Clusters 1 and 2 are topological isomers.

All-metallagermoxane with an adamantanoid cage structure: [(Cp*Ru(CO)2Ge)4(μ-O)6] (Cp* = η(5)-C5Me5).

In an attempt to synthesize a zero valent germanium compound, we have carried out the reaction of [(Cp*RuCO)(GeCl2)]2, 1 with potassium metal that led to the formation of a metallagermoxane [(Cp*Ru(CO)2Ge)4(μ-O)6], 2. Compound 2 is the first example of a tetrametallagermoxane with an exo-{Cp*Ru(CO)2} fragment. DFT calculations were used to examine the key intermediates associated with the formation of 2.