Initial decarbonylation of C~MOO~~(CO)~~[~~-~~-C(O)CH~TO~] (4; Cp = q5-c&, To1 = p-C,&,Me) with Me3NO/MeCN followed by reaction with dihydrogen gives the dihydride complex C~MOOS~(CO)~~(J~-H)2[p3-q2-C(0)CH2Tol] (5) in a quantitative yield. Thermolysis of 5 induces scission of the acyl C-O to afford the three isomeric hydridwoxwlidene compounds C~MOO~(CO)~~-H)(J~-O)~-CHCH,TO~) (6a-c).Complexes 6a,b are not chromatographically separable, and compound 6c is produced either by heating a mixture of 6a and 6b in toluene (100 "C) or by treating with hydrochloric acid. Compounds 4,5, and 6a-c have been isolated as crystalline solids and have been characterized by spectroscopic (infrared, mass, ' H and '9c NMR) data The molecular structure of compound 6c has been determined by a single-crystal X-ray diffraction study. Complex 6c crystallizes in the orthorhombic space grou Pmn2' with a = 12.438 weight 1118.9. Diffraction data were collected on a CAD4 diffractometer, and the structure was refined to R(F) = 6.0% and &(F) = 7.5% for 1236 data (Mo Ka radiation). The molecule is based upon a tetrahedral Moos3 core. Each osmium atom is coordinated to three terminal CO ligands, and the molybdenum atom is bonded to an q6-CsHs ligand. The p-oxo, p-alkylidene, and p-hydrido ligands bridge each edge of one of the Os-Os-Mo triangular faces. The pox0 and p-akylidene groups are disordered out of the crystallographic mirror plane which bisects the Moos3 core. The p-hydride ligand is believed to span the elongated Oe-Oa edge of the tetrahedron. The aryl moiety (CH,Tol) is dispoeed toward the p-oxo ligand, which clearly indicates that 6c is formed from a mixture of 68 and 6b by an apparent rotation of the palkylidene carbon. (7) A, b = 8.797 (2) A, c = 11.846 (4) A, V = 1296 (1) A3, and D(calcd) = 2.87 g cm-1: for 2 = 2 and molecular Introduction Acyl ligands have been widely discussed as potential surface intermediates in hydracarbon chain growth during Fischer-Tropech reactions.2 Reduction of the acyl ligands
Diaqua(3,6,13,4,0 118 ,0 712 ]docosane)zinc]dichloride reacts with sodium cyanate to yield zinc hemichloride sesquiisocyanate (3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0 118 ,0 7l2 ]docosane) trihydrate, [Zn(L)(NCO)] + [(CI) 05 (NCO) 05 ]--3H 2 O [monoclinic P2,/n, a = 10.530 (3), b = 9.315(2), c =27.188(3) Α, β = 92.58(1)°, V= 2664.1(9) A 3 , Z = 4], whose five-coordinate zinc atom shows square pyramidal-ZnN 5 coordination. The nitrogen atoms of the tetraaza macrocycle comprise the basal plane of the coordination polyhedron around the zinc atom. The dichloride reacts with sodium nitrite to yield a 1/1 complex with zinc chloride nitrite. The crystal structure of this complex, formulated as [Zn(L)(CI) 05 (NO 2 ) 05 ] + [(CI) 05 (NO 2 ) 05 ]" [triclinic P-1, a = 7.992(1), b = 8.769(1), c = 9.024(6) Α, α = 86.36(2), β = 74.99(3), γ = 81.12(1)°, V = 603.4(4) A 3 , Z= 1], features both square-pyramidal ZnN s as well as square-pyramidal ZnCIN 4 zinc atoms. IntroductionInorganic zinc(ll) complexes of macrocyclic polyamines have been used as models for zinc-containing active sites in enzymes such as carbonic anhydrase (CA) and carboxypeptidases [1-3], The best structural and chemical model for CA is the complex with the triaza macrocycle 1,5,9-triazacyclododecane [4]; the pK a (in water) of the complex, which possesses a [Zn-OH]' unit, is 7.3, which is almost that of CA itself. Models based on tetraaza macrocycles such as 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadecane-1(17),2,11,13,15-pentaene [5] (pK a = 8.7 [6]) and 1,4,7,10-tetraazacyclododecane [7] (pK a = 8.0 [4]) have also been examined. The CA-inhibitor [8] thiocyanate anion binds to the zinc atom through its nitrogen end in the zinc isothiocyanate complex of 1,5,9-triazacyclododecane [/NH(CH 2 ) 2 NH(CH 2 ) 3 NH(CH 2 ) 3 /]; the zinc atom shows trigonal-bipyramidal coordination [9], On the other hand, the zinc dichloride dihydrate complex of 3, 14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0 118 ,0 712 ]docosane has the zinc atom in an octahedral environment; the metal atom is coordinated to two water molecules in [Zn(L)(H 2 0) 2 ] + 2[Clj" [10]. As the tetraaza macrocycle is larger than the triaza macrocycle, its four nitrogen atoms are able to arrange themselves form a square plane around the zinc atom. This complex when treated with sodium cyanate furnishes the zinc hemichloride sesquiisocyanate complex of the macrocycle, whose crystal structure is detailed in this report. This report also describes the structure of the product that is obtained when sodium nitrite is used in place of sodium cyanate in the analogous reaction; the structure has been erroneously reported as the zinc dinitrite complex [11]·
Abstract. In this paper, we investigate chemical hyperstructures of chemical reactions for iron and indium using hyperstructure theory.
The complex [Zn(L)(N0 2 ) 2 ] (1) (L: 3,14-dimethyl-2,6,13,17-tctraazatricyclo[14,4,0" 8 ,0 7,2 ]docosane) has been synthesized and characterized by X-ray crystallography. 1 crystallizes in the triclinic system, space group PI, a = 7.992 (1)Ä, b = 8.769(1)Ä, c = 9.024(6)A, a= 86.36(2)° , >9= 74.99(3)° , r= 81.12° , V= 603.4(4) A 3 , Ζ = 1, R = 0.088. R w = 0.198. The coordination of the zinc atom is a distorted octahedral geometry with bonds to the four nitrogen atoms of macrocycle and to the axial nitrogen atoms of the nitrite group.
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