What Should One Know About the Croatian Chemical Nomenclature?

Načinjen je pregled najčešćih pogrešaka i zabluda vezanih uz hrvatsku kemijsku nomenklaturu. Objašnjena je razlika između nomenklature i nazivlja. Za kemijske elemente selenij, telurij, titanij i uranij ne bi trebalo rabiti zastarjela imena selen, telur, titan i uran. Jedan kemijski spoj može imati više ispravnih kemijskih imena. Treba razlikovati posvojne pridjeve izvedene iz imenâ kemijskih elemenata (npr. ugljikov, aluminijev, platinin) od gradivnih pridjeva izvedenih iz imenâ njihovih elementarnih tvari (npr. ugljični, aluminijski, platinski). Pri pisanju kemijskih imena treba paziti na pravila o uporabi razmaka i spojnice, a treba voditi računa i o pravilnoj uporabi kurziva. U hrvatskom jeziku prefiksi koji u supstitucijskoj nomenklaturi označuju halogene supstituente nisu identični prefiksima koji u koordinacijskoj nomenklaturi označuju halogene ligande.An overview of the most common mistakes and misconceptions concerning Croatian chemical nomenclature is presented. The difference between nomenclature and terminology is clarified. The chemical elements selenium, tellurium, titanium and uranium should not be named (in Croatian) by antiquated names selen, telur, titan and uran. Possessive adjectives derived from the names of chemical elements (e. g. ugljikov, aluminijev, platinin) should be distinguished from material adjectives derived from the names of their elementary substances (e. g. ugljieni, aluminijski, platinski). When writing chemical names, one should take care of the rules of the use of hyphens and spaces, as well as of the correct use of italic font. In Croatian, prefixes denoting halogen substituents in the substitution nomenclature differ from those denoting halogen ligands in the coordination nomenclature

Quasicrystals – Discovery, Structure and Properties

Kvazikristali su krutine čije strukture mogu posjedovati kristalografski nedopuštene rotacijske simetrije, primjerice 5. reda i ne posjeduju translacijsku invarijantnost, koja je karakteristična za klasične kristale. Svojstva im se bitno razlikuju od onih klasičnih kristala. Usprkos tomu što su metali, slabi su vodiči električne struje i topline te su tvrdi i krti. Strukture im se mogu opisati kao kvaziperiodične. Matematički je opis kvaziperiodičnosti prethodio otkriću kvazikristala, te je time bitno olakšao proučavanje i tumačenje njihovih struktura i svojstava. U ovome je radu dan pregled najvažnijih rezultata i spoznaja o kvazikristalima i kvaziperiodičnosti.Quasicrystals are solid materials the structures of which can have crystallographically forbidden symmetries, e.g. of the fifth order, and do not have the translational invariance charactistic for classical crystals. Their properties are quite different from those of classical crystals. Although all being metals, they are poor conductors of heat and electricity and are hard and brittle. Their structures can be described as quasiperiodic. The mathematical description of quasiperiodicity predates the discovery of quasicrystals and has greatly facilitated the study and the interpretation of the quasicrystals’ structures and properties. This paper provides an overview of the most basic results of the study of quasicrystals and quasiperiodicity

Benzyl Dihydrazone versus Thiosemicarbazone Schiff Base: Effects on the Supramolecular Arrangement of Cobalt Thiocyanate Complexes and the Generation of CoN6 and CoN4S2 Coordination Spheres

In this study, we examine the coordination chemistry of benzyl dihydrazone and thiosemicarbazone Schiff bases featuring different chelation modes, steric bulk, and reactivities towards cobalt(II) thiocyanate. The tetradentate benzyl dihydrazone ligands coordinate to the Co(SCN)2 fragment to form CoN6 coordination spheres (1–3), whereas the thiosemicarbazone ligands provide CoIII complexes featuring CoN4S2 coordination spheres (4 and 5) and charge-balancing anions {SCN– and [Co(SCN)4]2– for 4 and 5, respectively}. Hirshfeld surface (HS) analysis revealed a substituent effect that results in an increasing number of H···H contacts in the order –H < –CH3 < –Ph (1–3, respectively). The H bonding in 4 and 5 as well as the associated energies were computed by the DFT approach, and these interactions appear to be crucial for the formation of the supramolecular systems. The DFT study also suggested that the H-bonded dimers in 5 are examples of the recently described “antielectrostatic” H bonds. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Benzyl Dihydrazone versus Thiosemicarbazone Schiff Base: Effects on the Supramolecular Arrangement of Cobalt Thiocyanate Complexes and the Generation of CoN6 and CoN4S2 Coordination Spheres

In this study, we examine the coordination chemistry of benzyl dihydrazone and thiosemicarbazone Schiff bases featuring different chelation modes, steric bulk, and reactivities towards cobalt(II) thiocyanate. The tetradentate benzyl dihydrazone ligands coordinate to the Co(SCN)2 fragment to form CoN6 coordination spheres (1–3), whereas the thiosemicarbazone ligands provide CoIII complexes featuring CoN4S2 coordination spheres (4 and 5) and charge-balancing anions {SCN– and [Co(SCN)4]2– for 4 and 5, respectively}. Hirshfeld surface (HS) analysis revealed a substituent effect that results in an increasing number of H···H contacts in the order –H < –CH3 < –Ph (1–3, respectively). The H bonding in 4 and 5 as well as the associated energies were computed by the DFT approach, and these interactions appear to be crucial for the formation of the supramolecular systems. The DFT study also suggested that the H-bonded dimers in 5 are examples of the recently described “antielectrostatic” H bonds. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Pb⋯X (X = N, S, I) tetrel bonding interactions in Pb(II) complexes: X-ray characterization, Hirshfeld surfaces and DFT calculations

Four new Pb(ii) complexes of nicotinoylhydrazone and picolinoylhydrazone-based ligands and three different anionic co-ligands (acetate, thiocyanate and iodide) have been synthesized and characterized by structural, analytical and spectroscopic methods. The ligands coordinate to the Pb(ii) metal center in a tridentate fashion via two nitrogen and one oxygen donor atoms either in mono-deprotonated or in neutral forms. Single-crystal X-ray crystallography reveals that the molecular complexes aggregate into larger entities depending upon the anion coordinated to the metal centre. The Pb(ii) center is hemidirectionally coordinated and, consequently, it is sterically ideal for establishing tetrel bonding interactions. Consequently, in the crystal structures of all the complexes, the Pb participates in short contacts with nitrogen, iodide or sulphur atoms. These contacts are shorter than the sums of the van der Waals radii and larger than the sums of the covalent radii, therefore they can be defined as non-covalent tetrel bonding interactions. They interconnect the covalently bonded units (monomers or dimers) into supramolecular assemblies (1D infinite chains and 3D structures). Hirshfeld surface analysis and fingerprint plots have been used to analyse the contribution of contacts involving the Pb atom. We have analysed the interesting supramolecular assemblies observed in the solid state of all four complexes by means of DFT calculations and characterized them using Bader's theory of atoms-in-molecules. © 2018 The Royal Society of Chemistry

Pb⋯X (X = N, S, I) tetrel bonding interactions in Pb(II) complexes: X-ray characterization, Hirshfeld surfaces and DFT calculations

Four new Pb(ii) complexes of nicotinoylhydrazone and picolinoylhydrazone-based ligands and three different anionic co-ligands (acetate, thiocyanate and iodide) have been synthesized and characterized by structural, analytical and spectroscopic methods. The ligands coordinate to the Pb(ii) metal center in a tridentate fashion via two nitrogen and one oxygen donor atoms either in mono-deprotonated or in neutral forms. Single-crystal X-ray crystallography reveals that the molecular complexes aggregate into larger entities depending upon the anion coordinated to the metal centre. The Pb(ii) center is hemidirectionally coordinated and, consequently, it is sterically ideal for establishing tetrel bonding interactions. Consequently, in the crystal structures of all the complexes, the Pb participates in short contacts with nitrogen, iodide or sulphur atoms. These contacts are shorter than the sums of the van der Waals radii and larger than the sums of the covalent radii, therefore they can be defined as non-covalent tetrel bonding interactions. They interconnect the covalently bonded units (monomers or dimers) into supramolecular assemblies (1D infinite chains and 3D structures). Hirshfeld surface analysis and fingerprint plots have been used to analyse the contribution of contacts involving the Pb atom. We have analysed the interesting supramolecular assemblies observed in the solid state of all four complexes by means of DFT calculations and characterized them using Bader's theory of atoms-in-molecules. © 2018 The Royal Society of Chemistry