Density Functional Theory implemented in ADF 2012.01 was applied to authenticate the relative spatial displacements of the two metals and the surrounding CO groups in nine bi-nuclear transition metal carbonyls. A number of NMR parameters namely Chemical Shifts of the metals, the carbon and the oxygen species (δ M ,δ 13C, δ 17O), their Total NMR Shielding Tensors (σ M , σ 13C ,σ 17O ) along with their four paramagnetic [paramagnetic (b^) tensor, paramagnetic (u^) tensor, paramagnetic (s^) tensor and paramagnetic gauge tensor] and two diamagnetic [diamagnetic core tensor and diamagnetic valence tensor] contributions were obtained. These parameters [δ 13C, δ 17O, σ 13C and σ17O] were compared with the Coordination Shifts [Δδ13C]. The Effective Spin Hamiltonian (H^) of the two metals and all the bonded carbon atoms were calculated. In none of these carbonyls, the two metals or any two COs were both spatially and magnetically equivalent. In the eight metal carbonyls, both the metals were spatially equivalent. But, there were many spatially equivalent CO groups. Again, when the perturbing species was the first metal and responding species was the spatially equivalent second metal or vice versa, their k and j sets possessed the same values. Also, for CO groups directly attached to one metal and their spatially equivalent CO s attached to the second metal, the k and j values of 13C had same values. It classified all the (3n-6) fundamental bands of these carbonyls into four types according to their IR- / Raman- activity. Their NMR results corroborated well with the reported vibration spectral (IR/Raman) results in confirming their π – acid character. Lastly, the optimization and thermal parameters of these carbonyls were also calculated.

Density Functional Theory implemented in ADF 2012.01 was used to know about the relative spatial displacements of the three/four metals and the 12 surrounding CO groups in the 5 poly-nuclear transition metal carbonyls. A number of NMR parameters namely Chemical Shifts of the metals, the carbon and the oxygen species (δ M, 13δ C, δ17O), their Total NMR Shielding Tensors (σ M, σ 13C, σ17O) along with their four paramagnetic [paramagnetic (b^) tensor, paramagnetic (u^) tensor, paramagnetic(s^) tensor and paramagnetic gauge tensor] and two diamagnetic [diamagnetic core tensor and diamagnetic valence tensor] contributions were obtained. These parameters [δ 13C, δ 17O, σ 13C and σ17O] were also compared with the Total Coordination Shifts [Δδ13CT and Δδ17OT], the atomic electron valence density (integrated)/ L value of oxygen and the charges on both oxygen and metal atoms. The Effective Spin Hamiltonian (H^) of the metals and the carbon atoms were calculated from their k and j values. In none of these carbonyls, the three/four metals and any two among the 12COs were both spatially and magnetically equivalent. Of course, many metals and CO groups were found to be spatially equivalent. When the perturbing species was the first metal and the responding species was the spatially equivalent other metal /s or vice versa, their sets of k and j values remained to be the same. Similarly, for CO groups directly attached to one metal and the spatially equivalent CO groups attached to the other metal /s, the sets of k and j values of 13C nuclei remained to be the same. It classified all the (3n-6) fundamental bands of the carbonyls into four types according to their IR-/ Raman- activity. The NMR studies corroborated well with the results already known from their IR/Raman studies in confirming the π – acid character of the carbonyls. Some optimization and thermal parameters of these carbonyls were also calculated.

The necessity for having an efficient medium access control (MAC) protocol is highly obvious with the emergence of wireless sensor networks (WSNs). The MAC protocol has increasingly been significant in advancing the performance of WSNs. In this paper, a low duty cycle, energy-efficient and mobility-based Boarder Node Medium Access Control (BN-MAC) hybrid protocol is introduced for WSNs that controls overhearing, idle listening and congestion issues by preserving energy over the WSNs. Further, the BN-MAC hybrid protocol handles the scalability and mobility of nodes using the pheromone termite (PT) analytical model. BN-MAC leverages the features of contention and schedule-based MAC protocols. The contention encompasses the novel semi-synchronous approach that helps obtain faster access to the medium. The schedule-based part helps reduce the collision and overhearing problems. \n The idle listening control (ILC) model is embedded within the BN-MAC that administers the nodes to go to sleep after performing their tasks to saves additional energy. The least distance smart neighboring search (LDSNS) model is used to determine the shortest and most efficient path in a one-hop neighborhood. \nEvaluation of the BN-MAC is conducted using network simulator-2 (ns2), then compared its quality of service (QoS) parameters with other known hybrid MAC protocols including X-MAC, Zebra medium access control (Z-MAC), mobility-aware SMAC (MS-MAC), advertisement-based MAC (A-MAC), Adaptive Duty Cycle SMAC (ADC-SMAC) and Mobile Sensor (MobiSense) MAC protocols.