46 research outputs found
Análisis comparativo del uso de las tecnologías de la información y comunicación (TIC), en la gestión empresarial de los hoteles ubicados en la ciudad de Estelí, Nicaragua entre los años 2008 y 2016
La presente investigación está dirigida al análisis de las Tecnologías de Información y Comunicación (TIC) en la gestión hotelera de los hoteles de la ciudad de Estelí, utilizando como referente un estudio realizado en 2008 y comparando resultados con el año 2016, es un estudio de tipo cuantitativo, se aplicaron 19 encuestas a gerentes, administradores de los hoteles y entrevistas para complementar los análisis estadísticos. Como resultado se encontró que hay cambios significativos en la implementación de nuevas tecnologías como: la incorporación de nuevos equipos tecnológicos (hardware), e incremento de programas (software) específicos para hoteles. El 30% de los encuestados afirmó que la principal limitante es la falta de capacitación y el 28% indica que los altos costos para incorporar las TIC, encontrando diferencia en las dificultades entre los dos años. La hipótesis planteada se acepta en un 84% las TIC han provocado cambios en la gestión empresarial y el uso de tecnología está dirigido al marketing de los hoteles a través del internet. Se proponen seis líneas estratégicas para la mejora del uso de las TIC
«Малобюджетний» маркетинг
В умовах сьогоднішньої економічної кризи, яка зачепила всі вітчизняні підприємства, та постійного зниження української національної валюти актуальними стають питання пошуку способів економії коштів. Вирішенням таких проблем може стати «мало бюджетний» маркетинг, який допоможе розвиватися підприємству з використанням мінімальної кількості ресурсів.
«Малобюджетний» маркетинг – це маркетингові інструменти залучення й утримання клієнтів, які припускають мінімальні витрати, а іноді можна взагалі обійтися без бюджету
From Five to Five: Titanium Ketimine Complexes with Monoaza-butadiene η<sup>4</sup>‑Coordination Mode and Hidden η<sup>2</sup>‑Imine Reactivity
In the reactions
of LTiCl<sub>3</sub> (L: Cp*, Cp), Mg, and PhNC(<i>p</i>-tolyl)<sub>2</sub> (<b>1</b>) the formation of η<sup>4</sup>-ketimine complexes Cp*Ti(Cl)(η<sup>4</sup>-PhNC(<i>p</i>-tolyl)<sub>2</sub>) (<b>2a</b>) and CpTi(Cl)(η<sup>4</sup>-PhNC(<i>p</i>-tolyl)<sub>2</sub>) (<b>2b</b>) are observed. Their “nonclassic” five-membered
titanium monoazabutadiene envelope coordination modes, involving one
of the <i>p</i>-tolyl substituents, is confirmed by single
crystal X-ray diffraction analysis of <b>2b</b>. In reactions
of <b>2</b> with aldehydes, ketones, alkynes, carbodiimides,
isocyanates, isothiocyanates, and imines five-membered titanacycles
are formed in a regioselective manner. This behavior is in agreement
with a hidden η<sup>2</sup>-imine reactivity. All reaction products
are fully characterized, including single crystal X-ray diffraction
studies. For the PhCCH insertion products (<b>4b</b>, <b>4c</b>) the formation of Ti–C(Ph) units are observed.
By insertion of the isocyanate CyNCO the formation of a Ti–N
bond in <b>6a</b> is preferred in comparison to the insertion
of the isothiocyanate PhNCS, where a Ti–S bond is formed (<b>7a</b>). By reacting <b>2a</b> with aldimine PhNC(H)(<i>p</i>-tolyl) the nonsymmetric titanaimidazolidine derivative <b>8a</b> is formed by subsequent ketimine–aldimine coupling.
By derivatization of <b>2a</b> with LiN(Me)Cy the formation
of a the titanadihydropyrrole <b>9a</b> is observed, caused
by a 1,3-<i>H</i>-shift. <b>2</b> appears to be inert
toward a broad range of terminal olefins. Reacting <b>2a</b> with allyl ethyl ether results in a spontaneous ether cleavage reaction
to <b>10a</b>
Activation of 7‑Silanorbornadienes by N‑Heterocyclic Carbenes: A Selective Way to N‑Heterocyclic-Carbene-Stabilized Silylenes
The synthesis of
hydridosilylenes Ter(H)Si: <b>3a</b> (Ter:
2,6-bis(2,4,6-trimethylphenyl)phenyl) and Ter*(H)Si: <b>3b</b> (Ter*: 2,6-bis(2,4,6-tri<i>iso-</i>propylphenyl)phenyl)
stabilized by the N-heterocyclic carbene (NHC) ImMe<sub>4</sub> is
reported. The synthesis of stabilized hydridosilylenes <b>3</b> was accomplished by a previously unknown NHC-induced fragmentation
of silanorbornadiene derivatives. Structural studies of the stabilized
silylenes <b>3</b> and of its Fe(CO)<sub>4</sub> complex <b>12</b> accompanied by a theoretical analysis of their bonding
situation indicate that stabilized silylenes such as <b>3</b> can be regarded as neutral silyl anion equivalents. A computational
investigation of the reaction course indicate a virtual one-step reaction
between the NHC and the silanorbornadiene. A theoretical assessment
of the scope and limitations of this reaction suggests that it is
general and can be used also for the synthesis of other carbene analogues
such as germylenes and phosphinidenes
Formation of δ‑Lactones by Cerium-Catalyzed, Baeyer–Villiger-Type Coupling of β‑Oxoesters, Enol Acetates, and Dioxygen
Formation of δ-lactones is
observed when cyclopentanone-2-carboxylates
are converted in a cerium-catalyzed reaction with α-aryl vinyl
acetates under oxidative conditions. The products of this transformation
possess a 1,4-dicarbonyl constitution together with a quaternary carbon
center. Atmospheric oxygen is the oxidant in this process, which can
be regarded as ideal from economic and ecological points of view.
Further advantages of this new C–C coupling and oxidation reaction
are its operational simplicity and the application of nontoxic and
inexpensive CeCl<sub>3</sub>·7 H<sub>2</sub>O as precatalyst.
This so far unprecedented reaction is proposed to proceed via 1,2-dioxane
derivatives, which decompose under formation of an oxycarbenium cation
in a Baeyer–Villiger-type pathway. This mechanistic picture
is supported by the observation that electron-rich (donor substituted
or heteroaromatic) enol esters give higher yields than electron deficient
congeners. Apart from 1,4-diketones and α-hydroxylated β-oxoesters
formed as byproducts, the yields of δ-lactones range from moderate
to good (up to 74%)
Sequential Multicomponent Reactions and a Cu-Mediated Rearrangement: Diastereoselective Synthesis of Tricyclic Ketones
A novel
Cu-mediated rearrangement reaction based on bisamides containing
a thiazolidine substructure opens the possibility for diastereoselective
synthesis toward a tricyclic annulated and bridged heterocyclic system.
The required precursors are easily synthesizable by a two-step synthetic
pathway using the concept of sequential multicomponent reactions,
i.e. the Asinger and Ugi reactions. Due to this synthesis strategy,
a number of unique tricyclic heterocycles, characterized by high diversity,
are synthesized in an effective manner
Zwitterionic d<sup>0</sup> Metal Complexes [(Cy<sub>2</sub>N)<sub>3</sub>M]<sup>+</sup>[(μ-Me)B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>]<sup>−</sup> (M = Ti, Zr, Hf) Derived from Tris(dicyclohexylamido)methyl Metal Precursors
The synthesis and
characterization of tris(dicyclohexyl)amido hafnium
complexes ClHf(NCy<sub>2</sub>)<sub>3</sub> (<b>1-Hf</b>) and
MeHf(NCy<sub>2</sub>)<sub>3</sub> (<b>2-Hf</b>) are presented.
The reactions of the group 4 derivatives of this compound class (MeM(NCy<sub>2</sub>)<sub>3</sub>; M = Ti (<b>2-Ti</b>), Zr (<b>2-Zr</b>), Hf (<b>2-Hf</b>)) with B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> are investigated. Their reactions with strong Lewis acids
lead to the first examples of zwitterionic group 4 complexes employing
three amido ligands at the electrophilic metal center ([(Cy<sub>2</sub>N)<sub>3</sub>M]<sup>+</sup>[(μ-Me)B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>]<sup>−</sup>). The solid-state structures of
all of the betaines (<b>3-Ti</b>, <b>3-Zr</b>, <b>3-Hf</b>) are presented and compared. In all homologues the methyl group
is abstracted by the Lewis acid but remains in interaction with the
electron-deficient metal center, resulting in a linearly bridging
methyl group. The M···C distances of <b>3-M</b> are elongated by 0.25 Å (av) in comparison to <b>2-M</b>
Activation of 7‑Silanorbornadienes by N‑Heterocyclic Carbenes: A Selective Way to N‑Heterocyclic-Carbene-Stabilized Silylenes
The synthesis of
hydridosilylenes Ter(H)Si: <b>3a</b> (Ter:
2,6-bis(2,4,6-trimethylphenyl)phenyl) and Ter*(H)Si: <b>3b</b> (Ter*: 2,6-bis(2,4,6-tri<i>iso-</i>propylphenyl)phenyl)
stabilized by the N-heterocyclic carbene (NHC) ImMe<sub>4</sub> is
reported. The synthesis of stabilized hydridosilylenes <b>3</b> was accomplished by a previously unknown NHC-induced fragmentation
of silanorbornadiene derivatives. Structural studies of the stabilized
silylenes <b>3</b> and of its Fe(CO)<sub>4</sub> complex <b>12</b> accompanied by a theoretical analysis of their bonding
situation indicate that stabilized silylenes such as <b>3</b> can be regarded as neutral silyl anion equivalents. A computational
investigation of the reaction course indicate a virtual one-step reaction
between the NHC and the silanorbornadiene. A theoretical assessment
of the scope and limitations of this reaction suggests that it is
general and can be used also for the synthesis of other carbene analogues
such as germylenes and phosphinidenes
Hafnocene-based Bicyclo[2.1.1]hexene Germylenes – Formation, Reactivity, and Structural Flexibility
2,5-Disilylsubstituted
germole dianions <b>1</b> react with
hafnocene dichloride to give hafnocene-based bicyclo[2.1.1]hexene
germylenes <b>3</b>. Their formation proceeds via hafnocene-germylene
complexes <b>2</b> that were identified by NMR and UV spectroscopy.
Germylenes <b>3</b> are stabilized by homoconjugation between
the empty 4p(Ge) orbital and the π-bond of the innercyclic C<sup>2</sup>C<sup>3</sup> double bond. This interaction can be
understood as σ<sup>2</sup>, π-coordination of the butadiene
part to the dicoordinated germanium atom that leaves the 16e<sup>–</sup> hafnocene moiety electronically unsaturated. We demonstrate that
this new class of germylenes might serve as ligand to a variety of
low-valent transition-metal complexes. The structure of the germylene
ligand in complexes with Fe(0), Ni(0), and Au(I) and in reaction products
with N-heterocyclic carbenes showed an intriguing structural flexibility
that allows to accommodate different electronic situations at the
ligating germanium atom. The origin of this structural adaptability
is the interplay between the topological flexible unsaturated germanium
ring and the hafnocene group
Zwitterionic d<sup>0</sup> Metal Complexes [(Cy<sub>2</sub>N)<sub>3</sub>M]<sup>+</sup>[(μ-Me)B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>]<sup>−</sup> (M = Ti, Zr, Hf) Derived from Tris(dicyclohexylamido)methyl Metal Precursors
The synthesis and
characterization of tris(dicyclohexyl)amido hafnium
complexes ClHf(NCy<sub>2</sub>)<sub>3</sub> (<b>1-Hf</b>) and
MeHf(NCy<sub>2</sub>)<sub>3</sub> (<b>2-Hf</b>) are presented.
The reactions of the group 4 derivatives of this compound class (MeM(NCy<sub>2</sub>)<sub>3</sub>; M = Ti (<b>2-Ti</b>), Zr (<b>2-Zr</b>), Hf (<b>2-Hf</b>)) with B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> are investigated. Their reactions with strong Lewis acids
lead to the first examples of zwitterionic group 4 complexes employing
three amido ligands at the electrophilic metal center ([(Cy<sub>2</sub>N)<sub>3</sub>M]<sup>+</sup>[(μ-Me)B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>]<sup>−</sup>). The solid-state structures of
all of the betaines (<b>3-Ti</b>, <b>3-Zr</b>, <b>3-Hf</b>) are presented and compared. In all homologues the methyl group
is abstracted by the Lewis acid but remains in interaction with the
electron-deficient metal center, resulting in a linearly bridging
methyl group. The M···C distances of <b>3-M</b> are elongated by 0.25 Å (av) in comparison to <b>2-M</b>