Francisco Cervantes-Lee

Some mixed-ligand complexes of copper(II) with drugs of the quinolone family and (NN) donors. Crystal structure of [Cu(phen)(Cnx)(H2O)]NO3 · H2O

Abstract The synthesis of eight new mixed-ligand complexes of Cu(II) of the type [Cu(NN)(Antb)]X is reported, where NN is 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy), Antb is the anion of cinoxacin (Cnx) or oxolinic acid (Oxo), both drugs of the quinolone family. The crystal structure of [Cu(phen)(Cnx)(H 2 O)NO 3 · H 2 O is presented and discussed. The results here reported together with those previously reported for the complex [Cu(phen)(Nal)(H 2 O)]NO 3 · 3H 2 O and preliminary crystal data for the complex [Cu(bipy)(Oxo)]NO 3 · H 2 O, suggest that all the quinolone type drugs behave in a similar way as ligands under equivalent conditions.

Synthesis, structure, and reactivity of the permethylated decasilane (Me3Si)3SiSiMe2SiMe2SiMe3)3

Abstract The reaction between ClMe 2 SiSiMe 2 Cl and two equivalents of (Me 3 Si) 3 SiLi · 3THF resulted in a 40% yield of (Me 3 Si) 3 SiSiMe 2 SiMe 2 Si(SiMe 3 ) 3 , I . I crystallized in space group P 1 , a = 9.229(2) A , b = 9.312(2) A , c = 13.709(3) A , α = 104.15(2)°, β = 91.35(2)°, γ = 114.64(2)° . The internal SiSi bond lengths ((Me 3 Si) 3 SiSiMe 2 ) ( B ) and Me 2 SiSiMe 2 ) ( C ) are equivalent at 237.5(1) pm and 237.4(2) pm, respectively, and marginally longer than the terminal Me 3 SiSi bonds A which are in range 234.5(1)–236.1(2) pm. The Me 3 SiSiSiMe 2 angle of 115.3(1)° and Me 3 SiSiSiMe 2 angle of 117.1(1)° are the major structural deformations that reflect the steric complexity of the molecule. Photochemical irradiation of I in CCl 4 leads to predominant cleavage of the central SiSi bond C with minor cleavage of bond B ; photochemistry in hexane is more indiscriminate, both B and C were homolytically cleaved but silylene eliminations and secondary reactions also occurred. Treatment with Li or MeLi led to cleavage of SiSi bonds B and C . In the case of Li, predominant cleavage of B was observed (> 90%), whereas with MeLi cleavage took place at bond C (> 90%).

Structural and Magnetic Properties of the Topologically Novel 2-D Material Cu9F2cpa)6: A Triangulated Kagome - Like Hexagonal Network of Cu(II) Trimers Interconnected by Cu(II) Monomers

Abstract Cu9F2(cpa)6 xH2O (cpa = carboxypentonic acid) has been synthesized, and characterized by x-ray diffraction. It is isomorphous with the CI and Br congeners. Two coordinatively different Cu(II) ions comprise the unit cell: six Cutrimer (square pyramidal) and three Cumonomer (elongated octahedra). The six Cut ions form two exchange coupled trimeric clusters. Each of these trimers is bridged to three Cum sites; each Cum is connected to two trimers. The extended lattice is a hexagonal network with trimers at the vertices and Cum ions along the edges. Magnetic field-dependent magnetic susceptibility studies in the range 1.7 – 300 K demonstrate that the compound has a magnetic ground state which is highly field dependent at lower temperatures (< 20K). The interconnected triangulation suggests spin frustation. Theoretical results for this type of lattice are unknown, but analogies can be drawn to the Kagome lattice.

Crystal and molecular structures of the adducts of tri-p-tolyltin chloride, bromide and iodide with 4,4′-bipyridine

The structures of the three adducts [(p-tolyl)3SnX]2·4,4′-bipyridine (XCl, Br, I), have been established by X-ray diffraction techniques. The complexes are monoclinic, space group P21/c and Z=2. The cell parameters are: a=13.262(2), b=11.382(2), c=17.029(2) A and β=110.050(11)° for XCl; a=13.103(3), b=11.351(2), c=17.607(4) A and β=110.050(16)° for XBr; a=12.867(3), b=11.389(4), c=18.496(4) A and β=110.050(11)° for XI. The complexes are binuclear with a bridging 4,4′-bipyridine. The tin is in a trigonal bipyramidal environment with the p-tolyl groups on the equator and the X atom and an N of the bipyridine on the axis. The SnN bond distances are 2.668(3), 2.653(3) and 2.655(7) A, for XCl, Br and I, respectively. The SnX bond distances are 2.452(2), 2.691(1) and 2.830(1) A, for XCl, Br and I, respectively.

Supramolecular self-assembly involving cooperative use of dative coordinate, secondary and hydrogen bonding in solid [(Me3Sn)3 (μ-OH)2]+Br-

Abstract Trinuclear Sn3(μ-OH)2 moieties formed through coordinate dative bonds are associated into chains through secondary Sn⋯Br− interactions and further self-assembled in a three-dimensional network through O–H⋯Br− hydrogen bonds.

Synthesis and characterization of new germylferrocenyl, germylferrocenophane and polymeric germyleneferrocenylene systems

Abstract New germanium-bridged [1]ferrocenophanes Fe(η5-C5H4)2GeClR (1), (R=Me (1a), t-Bu (1b), Ph (1c)) were prepared by the reaction of Fe(η5-C5H4Li)2·TMEDA (TMEDA=tetramethylethylenediamine) with the corresponding chlorogermanes, RGeCl3 (R=Me, t-Bu, Ph). Ring-opening addition of HCl to 1c resulted in the formation of (η5-C5H4)Fe(η5-C5H5)GeCl2Ph (2) which was reacted with dilithioferrocene·TMEDA to form Fe(η5-C5H4)2FcPhGe (3). All complexes were characterized by 13C and 1H NMR, and the structure of Fe(η5-C5H4)2GeClPh was determined by single-crystal X-ray diffraction analysis and exhibits a dihedral angle between the planes of the cyclopentadienyl rings of 18.4°. Cyclic voltammetric analysis of 1a, 1b, and 1c in CH2Cl2 revealed that each ferrocenophane exhibits a reversible, one-electron oxidation, at a higher oxidation potential than that of ferrocene. The voltammogram of 3 shows two reversible redox processes, one for the ferrocenophane moiety and a second for the pendant ferrocene group. Thermal ring-opening of 3 produced good yields of the corresponding polymer [Fe(η5-C5H4)2FcPhGe]n.

The reaction between ferrocenyllithium and trimethylacetylchloride to form either trimethylacetylferrocene or 1,1′-bis(ferrocenyl)-2,2′-dimethylpro

Abstract The addition of ferrocenyllithium, FcLi, to trimethylacetylchloride, Me 3 CCOCl, yields trimethylacetylferrocene, FcCOCMe 3 , (I), in 77% yield, wh The single crystal structural analysis of the α-ferrocenylcarbinol (II) shows that it forms discrete cyclic dimers, with the component molecules held

Pentamethyldisilylmethyl derivatives of the transition metals, LMCH2SiMe2SiMe3 [LM = (η5-C5R5)M(CO)nn−, M = Fe, W, R = H, Me, n = 2, 3; (η5-C9H7)Fe(CO)2−; (η5-C5 H5)2MCl−, M = Ti, Zr, Hf]

Abstract Pentamethyldisilylmethyl derivatives of the transition metals have been synthesized, LMCH2SiMe2SiMe3 [LM = (η5-C5R5) M(CO)n−, M = Fe, W, R = H, Me, n = 2, 3; (η5-C9H7)Fe(CO)2−; (η5-C5H5) 2MCl−, M = Ti,Zr,Hf]. The cyclopentadienylcarbonyl complexes are photochemically labile with respect to rearrangement to LM-SiMe2 CH2SiMe3 and are also subject to base-induced migration to the cyclopentadienyl ring to form (η5-Me3SiCH2SiMe2C5H4) derivatives. The titanium, zirconium and hafnium complexes exhibit neither property; the only compound isolated from the photochemical treatment of these complexes being Me3SiSiMe3. Structural analyses of (η5-C5H5)W(CO)3 CH2SiMe2SiMe3 and its phosphine-substituted rearrangement product, (η5-C5H5)W(CO)2 (PPh3)SiMe2CH2SiMe3, are presented.

Organometalloidal derivatives of the transition metals: XXVII. Chemical and structural investigation of (ferrocenylacyl)germanes

Abstract (Ferrocenylacyl)germanes, (η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )COGeR 3 (R 3 = Me 3 (I), Ph 3 (II)) have been synthesized and their physical and structural properties investigated, both spectroscopically and via single crystal X-ray analysis. Basicity measurements, via H-bonding to phenol, indicate that I and II are less basic than their silicon analogs, a feature corroborated by infrared and structural analysis. Thus, the v (CO) frequencies for I and II at 1594 and 1596 cm −1 are approximately 18 cm −1 higher than the corresponding acylsilanes, and the CO bond lengths of 1.223 A are shorter than the silicon analogs, 1.231 A.

Photochemistry of bridged disilyldiiron complexes (SiMe2)[(η5-C5H4)Fe(CO) 2SiMe2SiMe2R]2, R=Me, Ph

Photochemical irradiation of the new bimetallic disilyliron complexes (SiMe 2 )[(η 5 -C 5 H 4 )Fe(CO) 2 SiMe 2 SiMe 2 R] 2 , R=Me, Ph, results in silylene elimination chemistry, as observed for the mono-metallic analogs, resulting in the formation of complexes (SiMe 2 )[(η 5 -C 5 H 4 )Fe(CO) 2 SiMe 2 R] 2 . The intermediate silyl(silylene) complexes can be intercepted with HMPA. Apart from a very reactive minor product that we have been unable to identify at this time, the proximity of the two transition metal centers has little impact upon the observed chemistry.