CO AS π-ACID or Pi-Acceptor Ligand (Urdu/Hindi/English) скачать в хорошем качестве

CO AS π-ACID or Pi-Acceptor Ligand (Urdu/Hindi/English)

#ChemQuest #Teaching #InorganicChemistry-II Pi acid ligands are one that is able to accept a large amount of electron density from the metal atom into its own empty pi or pi* orbital are known as pi acid or pi acceptor ligands. The intensity of crystal field splitting energy is increased by this form of interaction and are thus known as strong filed ligands. Carbon monoxide is an example of a pi-acid ligand (CO). Due to empty pi orbitals and a good sigma donor, CO is a good pi acceptor or Lewis acid. In the case of CO, the ligand sigma donates to an empty d-orbital while bonding to a metal and the filled d-orbitals of the metal donate to CO’s empty pi* orbitals, back donating. When a carbon atom is attached directly with the central metal atom, then metal carbonyls are formed. In these metals – carbonyls, the metal and the carbon bond M – C bond contains both sigmaσand piπcharacters. As we know a sigma bond is the basis for a pi – bond. The metal and the carbon sigma bond is formed by the donation of the lone pair of electrons of the carbonyl (CO) ligand into the vacant d – orbital of the metal. Now, the back bonding occurs and a pi – bond is formed as, this lone pair of electron from filled d – orbital of the metal – carbon bond goes into the vacant anti – bonding π∗ orbital of the carbonyl ligand. This interaction creates a synergic effect that creates a strong bond. Also, the intensity of the crystal field splitting also increases due to the strengthened interactions. So, as the electron is donated into the π∗ and πorbitals, and then accepted by the same (CO) ligand, therefore it is called as pi – acid ligands. Hence, carbon monoxide (CO) is a pi – acid ligand as it donates and then accepts the lone pair of electrons from the d – orbital of the metal. In chemistry, π backbonding, also called π backdonation, is when electrons move from an atomic orbital on one atom to an appropriate symmetry antibonding orbital on a π-acceptor ligand. It is especially common in the organometallic chemistry of transition metals with multi-atomic ligands such as carbon monoxide, ethylene or the nitrosonium cation. Electrons from the metal are used to bond to the ligand, in the process relieving the metal of excess negative charge. Compounds where π backbonding occurs include Ni(CO)4 and Zeise's salt. IUPAC offers the following definition for backbonding: A description of the bonding of π-conjugated ligands to a transition metal which involves a synergic process with donation of electrons from the filled π-orbital or lone electron pair orbital of the ligand into an empty orbital of the metal (donor–acceptor bond), together with release (back donation) of electrons from an nd orbital of the metal (which is of π-symmetry with respect to the metal–ligand axis) into the empty π*-antibonding orbital of the ligand.