Reactions of the IrVhydride [MeBDIDipp]IrH4{BDI=(Dipp)NC(Me)CH(Me)CN(Dipp); Dipp=2,6‐
- Award ID(s):
- 1827875
- NSF-PAR ID:
- 10280075
- Date Published:
- Journal Name:
- The Texas Journal of Science
- Volume:
- 73
- Issue:
- 1
- ISSN:
- 0040-4403
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract i Pr2C6H3} with E[N(SiMe3)2]2(E=Sn, Pb) afforded the unusual dimeric dimetallotetrylenes ([MeBDIDipp]IrH)2(μ 2‐E)2in good yields. Moreover, ([MeBDIDipp]IrH)2(μ 2‐Ge)2was formed in situ from thermal decomposition of [MeBDIDipp]Ir(H)2Ge[N(SiMe3)2]2. These reactions are accompanied by liberation of HN(SiMe3)2and H2through the apparent cleavage of an E−N(SiMe3)2bond by Ir−H. In a reversal of this process, ([MeBDIDipp]IrH)2(μ 2‐E)2reacted with excess H2to regenerate [MeBDIDipp]IrH4. Varying the concentrations of reactants led to formation of the trimeric ([MeBDIDipp]IrH2)3(μ 2‐E)3. The further scope of this synthetic route was investigated with group 15 amides, and ([MeBDIDipp]IrH)2(μ 2‐Bi)2was prepared by the reaction of [MeBDIDipp]IrH4with Bi(NMe2)3or Bi(Ot Bu)3to afford the first example of a “naked” two‐coordinate Bi atom bound exclusively to transition metals. A viable mechanism that accounts for the formation of these products is proposed. Computational investigations of the Ir2E2(E=Sn, Pb) compounds characterized them as open‐shell singlets with confined nonbonding lone pairs at the E centers. In contrast, Ir2Bi2is characterized as having a closed‐shell singlet ground state. -
null (Ed.)Salt metathesis reactions between a low-valent rhenium( i ) complex, Na[Re(η 5 -Cp)(BDI)] (BDI = N , N ′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate), and a series of amidinate-supported tetrylenes of the form ECl[PhC(N t Bu) 2 ] (E = Si, Ge, Sn) led to rhenium metallotetrylenes Re(E[PhC(N t Bu) 2 ])(η 5 -Cp)(BDI) (E = Si ( 1a ), Ge ( 2 ), Sn ( 4 )) with varying extents of Re–E multiple bonding. Whereas the rhenium–stannylene 4 adopts a σ-metallotetrylene arrangement featuring a Re–E single bond, the rhenium–silylene ( 1a ) and –germylene ( 2 ) both engage in π-interactions to form short Re–E multiple bonds. Temperature was found to play a crucial role in reactions between Na[Re(η 5 -Cp)(BDI)] and SiCl[PhC(N t Bu) 2 ], as manipulation of reaction conditions led to isolation of an unusual rhenium–silane, (BDI)Re(μ-η 5 :η 1 -C 5 H 4 )(SiH[PhC(N t Bu) 2 ]) ( 1b ) and a dinitrogen bridged rhenium–silylene, (η 5 -Cp)(BDI)Re(μ-N 2 )Si[PhC(N t Bu) 2 ] ( 1c ), in addition to 1a . Finally, the reaction of Na[Re(η 5 -Cp)(BDI)] with GeCl 2 ·dioxane led to a rare μ 2 -tetrelido complex, μ 2 -Ge[Re(η 5 -Cp)(BDI)] 2 ( 3 ). Bonding interactions within these complexes are discussed through the lens of various spectroscopic, structural, and computational investigations.more » « less
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Abstract Despite its electron deficiency, boron can form multiple bonds with a variety of elements. However, multiple bonds between boron and main-group metal elements are relatively rare. Here we report the observation of boron-lead multiple bonds in PbB2O–and PbB3O2–, which are produced and characterized in a cluster beam. PbB2O–is found to have an open-shell linear structure, in which the bond order of B☱Pb is 2.5, while the closed-shell [Pb≡B–B≡O]2–contains a B≡Pb triple bond. PbB3O2–is shown to have a Y-shaped structure with a terminal B = Pb double bond coordinated by two boronyl ligands. Comparison between [Pb≡B–B≡O]2–/[Pb=B(B≡O)2]–and the isoelectronic [Pb≡B–C≡O]–/[Pb=B(C≡O)2]+carbonyl counterparts further reveals transition-metal-like behaviors for the central B atoms. Additional theoretical studies show that Ge and Sn can form similar boron species as Pb, suggesting the possibilities to synthesize new compounds containing multiple boron bonds with heavy group-14 elements.
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Abstract The crystal structure, electron energy-loss spectroscopy (EELS), heat capacity, and anisotropic magnetic and resistivity measurements are reported for Sn flux grown single crystals of orthorhombic Pr2Co3Ge5(U2Co3Si5-type,
Ibam ). Our findings show thato -Pr2Co3Ge5hosts nearly trivalent Pr ions, as evidenced by EELS and fits to temperature dependent magnetic susceptibility measurements. Complex magnetic ordering with a partially spin-polarized state emerges nearT sp= 32 K, with a spin reconfiguration transition nearT M= 15 K. Heat capacity measurements show that the phase transitions appear as broad peaks in the vicinity ofT spandT M. The magnetic entropy further reveals that crystal electric field splitting lifts the Hund’s rule degeneracy at low temperatures. Taken together, these measurements show that Pr2Co3Ge5is an environment for complexf state magnetism with potential strongly correlated electron states. -
A s a c om pl e men t t o da ta d edupli cat ion , de lta c om p ress i on fu r- t he r r edu c es t h e dat a vo l u m e by c o m pr e ssi n g n o n - dup li c a t e d ata chunk s r e l a t iv e to t h e i r s i m il a r chunk s (bas e chunk s). H ow ever, ex is t i n g p o s t - d e dup li c a t i o n d e l t a c o m pr e ssi o n a p- p ro a ches fo r bac kup s t or ag e e i t h e r su ffe r f ro m t h e l ow s i m - il a r i t y b e twee n m any de te c ted c hun ks o r m i ss so me po t e n - t i a l s i m il a r c hunks , o r su ffer f r om l ow (ba ckup and r es t ore ) th r oug hpu t du e t o extr a I/ Os f or r e a d i n g b a se c hun ks o r a dd a dd i t i on a l s e r v i c e - d i s r up t ive op e r a t i on s to b a ck up s ys t em s. I n t h i s pa p e r, w e pr opo se L oop D e l t a t o a dd ress the above - m e n t i on e d prob l e m s by an e nha nced em b e ddi n g d e l t a c o m p - r e ss i on sc heme i n d e dup li c a t i on i n a non - i n t ru s ive way. T h e e nha nce d d elt a c o mpr ess ion s che m e co m b in e s f our key t e c h - ni qu e s : (1) du a l - l o c a li t y - b a s e d s i m il a r i t y t r a c k i n g to d e t ect po t e n t i a l si m il a r chun k s b y e x p l o i t i n g both l o g i c a l and ph y - s i c a l l o c a li t y, ( 2 ) l o c a li t y - a wa r e pr e f e t c h i n g to pr efe tc h ba se c hun ks to a vo i d ex t ra I/ Os fo r r e a d i n g ba s e chun ks on t h e w r i t e p at h , (3) c a che -aware fil t e r to avo i d ext r a I/Os f or b a se c hunk s on t he read p at h, a nd (4) i nver sed de l ta co mpressi on t o perf orm de lt a co mpress i o n fo r d at a chunk s t hat a re o th e r wi se f o r b i dd e n to s er ve as ba se c hunk s by r ew r i t i n g t e c hn i qu e s d e s i g n e d t o i m p r ove r es t o re pe rf o rma nc e. E x p e r i m e n t a l re su lts indi ca te t hat L oop D e l t a i ncr ea se s t he c o m pr e ss i o n r a t i o by 1 .2410 .97 t i m e s on t op of d e dup li c a - t i on , wi t hou t no t a b l y a ffe c t i n g th e ba ck up th rou ghpu t, a nd i t i m p r ove s t he res to re p er fo r m an ce b y 1.23.57 t i m emore » « less