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We show that a simple, reversible, P–P bond cleavage/coupling transformation in a well-defined mononuclear Ir(κ1-R2P-PR2) complex is possible under ambient conditions.

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The one‐step synthesis (33 % isolated yield) of a novel bicyclic diphosphane, [P(CH2)2NC6H4(4‐NMe2)]2, P−P(NMe2), from the reaction of [P(CH2OH)4]Cl and H2NC6H4(4‐NMe2) in methanol is described. Surprisingly, P−P(NMe2) displays excellent air/solution stability (towards H2O, CH3OH) and can also function efficiently as a bridging ligand. Hence reaction of P−P(NMe2) with [Pd(μ−Cl)(η3‐allyl)]2 (η3‐allyl=C3H5, C4H7) or [Pd(μ−Cl)(κ2−C9H12N)]2 affords the singly‐bridged complexes {Pd(Cl)(η3‐allyl)}2{μ‐P−P(NMe2)} 1 a/1 b and {Pd(Cl)(κ2−C9H12N)}2{μ‐P−P(NMe2)} 1 c whereas treatment with [MX2(η4‐cod)] (M=Pd, Pt; X=Cl, Br, I, Me; η4‐cod=cycloocta‐1,5‐diene) gave (MX2)2{μ‐P−P(NMe2)}2 2 a–e in high yields. Protonation of 2 a–d with HBF4 ⋅ OEt2 gave the corresponding dimethylammonium salts 3 a–d. Single crystal X‐ray studies have been undertaken on P−P(NMe2), 1 b, 2 a, 2 b ⋅ 2CDCl3, 2 d, 2 e, 3 a ⋅ 12CD3CN and 3 b ⋅ 12CD3CN. The P−P bond lengths in free/coordinated P−P(NMe2) remain similar across all compounds studied here and no M ⋅⋅⋅ M contacts were observed within the planar M2P4 ring. In 3 a/3 b the BF4− anion displays a unique secondary interaction with the inorganic six‐membered M2P4 core.

Over the last decade, unmanned aerial vehicles (UAVs) with antenna arrays have usually been employed for the enhancement of wireless communication in millimeter-wave bands. They are commonly used as aerial base stations and relay platforms in order to serve multiple users. Many beamforming methods for improving communication quality based on channel estimation have been proposed. However, these methods can be resource-intensive due to the complexity of channel estimation in practice. Thus, in this paper, we formulate an MIMO blind beamforming problem at the receivers for UAV-assisted communications in which channel estimation is omitted in order to save communication resources. We introduce one analytical method, which is called the analytical constant modulus algorithm (ACMA), in order to perform blind beamforming at the UAV base station; this relies only on data received by the antenna. The feature of the constant modulus (CM) is employed to restrict the target user signals. Algebraic operations, such as singular value decomposition (SVD), are applied to separate the user signal space from other interferences. The number of users in the region served by the UAV can be detected by exploring information in the measured data. We seek solutions that are expressible as one Kronecker product structure in the signal space; then, the beamformers that correspond to each user can be successfully estimated. The simulation results show that, by using this analytically derived blind method, the system can achieve good signal recovery accuracy, a reasonable system sum rate, and acceptable complexity.